+publisher:"Texas A&M University" +contributor:("Biggs, Douglas")

Texas A&M University

1. Smultea, Mari Ann. Behavioral Ecology of Cetaceans in the Southern California Bight.

Degree: PhD, Marine Biology, 2016, Texas A&M University

URL: http://hdl.handle.net/1969.1/157036

► A behavioral ecology perspective on cetaceans in the Southern California Bight (SCB) can contribute to science-based adaptive management in the context of expanding anthropogenic activities.… (more)

▼ A behavioral ecology perspective on cetaceans in the Southern California Bight (SCB) can contribute to science-based adaptive management in the context of expanding anthropogenic activities. Objectives were to (1) identify behaviors associated with habitat resource selection, (2) evaluate species differences related to body size, group size, and group cohesion, and (3) determine temporal behavioral patterns. Cetacean aerial surveys (87,735 km) were conducted in 2008-2013 in all months except December. Locations and behavioral data were recorded for blue whales (Balaenoptera musculus), fin whales (B. physalus), gray whales (Eschrichtius robustus), Risso’s dolphins (Grampus griseus), common bottlenose dolphins (bottlenose; Tursiops truncatus), and common dolphins (Delphinus delphis and D. capensis). Response variables (occurrence, behavioral state, group size, group cohesion) were analyzed relative to the explanatory variables calf presence, bottom depth, shore distance, slope, aspect, time of day, Julian day, season. Resource Selection Function (RSF) modeling predicted probability of habitat use relative to resource availability and behavioral state by contrasting environmental characteristics at locations of cetaceans and randomly selected points (n=35,167). During medium/fast travel, relative probability of habitat use by fin whales was highest in deep and eastern waters (p<0.05) of the San Nicolas and San Diego basins. Risso’s dolphins selectively (p<0.05) used nearshore waters more than expected relative to availability, especially San Clemente Island, and habitat use differed by behavioral state (rest/slow travel, medium/fast travel; p<0.05). Bottlenose dolphins selectively used (p<0.05) nearshore shallow waters more frequently than available, particularly near Santa Catalina Island. Behaviors varied by species, not solely by body size. Larger whales (blue, fin) and dolphins (Risso’s, bottlenose) occurred in smaller, less cohesive groups and were more likely to occur alone. Species-specific group size was larger with calf presence; cohesion was higher during peak reproductive seasons (calving/mating). Time of day influenced behavioral state in nocturnal-feeding Risso’s and common dolphins, which were less cohesive and more inactive (mill/rest/slow travel) near midday. Spatiotemporal variation in cetacean distribution may reflect short-term changes in reproductive condition, resource availability, and anti-predator behavior. Applications of this behavioral ecology perspective are discussed relative to management opportunities within the framework of protecting areas, endangered species, and species-specific sensitive time periods. Advisors/Committee Members: Wuersig, Bernd (advisor), Packard, Jane (committee member), Biggs, Douglas (committee member), Rooker, Jay (committee member).

Subjects/Keywords: Cetacean; behavior; California; dolphin; whale; conservation; adaptive management

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APA (6^th Edition):

Smultea, M. A. (2016). Behavioral Ecology of Cetaceans in the Southern California Bight. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/157036

Chicago Manual of Style (16^th Edition):

Smultea, Mari Ann. “Behavioral Ecology of Cetaceans in the Southern California Bight.” 2016. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/157036.

MLA Handbook (7^th Edition):

Smultea, Mari Ann. “Behavioral Ecology of Cetaceans in the Southern California Bight.” 2016. Web. 17 Jan 2021.

Vancouver:

Smultea MA. Behavioral Ecology of Cetaceans in the Southern California Bight. [Internet] [Doctoral dissertation]. Texas A&M University; 2016. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/157036.

Council of Science Editors:

Smultea MA. Behavioral Ecology of Cetaceans in the Southern California Bight. [Doctoral Dissertation]. Texas A&M University; 2016. Available from: http://hdl.handle.net/1969.1/157036

Texas A&M University

2. Martin, Lindsay Margaret. Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea.

Degree: MS, Oceanography, 2016, Texas A&M University

URL: http://hdl.handle.net/1969.1/157125

► There are many species of the genus Sargassum distributed in tropical and subtropical waters but only two, S. natans and S. fluitans, have an entirely… (more)

▼ There are many species of the genus Sargassum distributed in tropical and subtropical waters but only two, S. natans and S. fluitans, have an entirely pelagic life cycle and offer ecologically-supportive structures of different forms in otherwise nutrient-poor environments. Sargassum represents a keystone species supporting relatively high levels of biodiversity which is required for the maintenance of the health and resilience of a unique ecosystem currently facing many anthropogenic pressures. While studied for years, no simultaneous comparisons have been performed between the three regions in which Sargassum is most commonly found: the Gulf of Mexico, Caribbean, and Sargasso Sea. Dip-net Sargassum samples and associated macrofauna were collected from these three regions during the Spring/Summer of 2015 to examine differences in Sargassum species, structure, and faunal distribution. An unusually large abundance of the rare form S. natans VIII was seen in all three regions in addition to the more common forms of S. natans I and S. fluitans III. Isolated clumps and rows of Sargassum were equally common in all three regions while mats were comparatively rare. Sargassum from the Gulf, Caribbean, and Sargasso Sea shared five common (frequency >10%) species. Differences in the physical forms of Sargassum forms had a marked effect on fauna diversity and abundance. In all three regions, fewer individuals and species were found on the broad-leafed, less compact S. natans VIII than on the denser S. natans I and S. fluitans III. The majority of these species are benthic-like species that physically require the Sargassum substrate (unlike most fish), and therefore likely avoid loose S. natans VIII which offers less surface area and protection from predators. This study identifies the differences in macrofauna abundance and diversity between varieties of Sargassum and highlights the potential for dramatic community assemblage changes that could result from largescale Sargassum blooms and species shifts. Advisors/Committee Members: Biggs, Douglas (advisor), Knap, Anthony (committee member), Wells, RJ David (committee member), Siuda, Amy NS (committee member).

Subjects/Keywords: Sargassum; community; fauna; Atlantic; Gulf of Mexico; Sargasso Sea; Caribbean; algae

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APA (6^th Edition):

Martin, L. M. (2016). Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/157125

Chicago Manual of Style (16^th Edition):

Martin, Lindsay Margaret. “Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea.” 2016. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/157125.

MLA Handbook (7^th Edition):

Martin, Lindsay Margaret. “Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea.” 2016. Web. 17 Jan 2021.

Vancouver:

Martin LM. Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea. [Internet] [Masters thesis]. Texas A&M University; 2016. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/157125.

Council of Science Editors:

Martin LM. Pelagic Sargassum and Its Associated Mobile Fauna in the Caribbean, Gulf Of Mexico, and Sargasso Sea. [Masters Thesis]. Texas A&M University; 2016. Available from: http://hdl.handle.net/1969.1/157125

Texas A&M University

3. Smith, Kerri. Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador.

Degree: MS, Marine Biology, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11033

► A study was conducted using data compiled from two sources to test the hypothesis that killer whales display seasonal variability in their occurrence in the… (more)

▼ A study was conducted using data compiled from two sources to test the hypothesis that killer whales display seasonal variability in their occurrence in the Galapagos Marine Reserve (GMR), Ecuador. Three questions arise from this hypothesis: 1) do killer whale sightings display temporal variability; 2) are sightings spatially associated with resources; and 3) if sightings are spatially associated with resources, does the spatial association change temporally? I combined and evaluated two sets of GMR killer whale sighting data (n=154) spanning a twenty-year time frame collected via opportunistic sightings by an observer network and shipboard line-transect surveys. I tested for a (a) correlation between the total annual sightings and bi-annual seasonality (upwelling versus non-upwelling); (b) correlation between the total annual sightings and the Multivariate El Nino Southern Oscillation Index (MEI); (c) correlation between sightings, the MEI, and seasonality; (d) spatial association between sightings and resources; and (e) spatial change in sightings with seasonality. Sightings were roughly equally distributed between non-upwelling (56%) and upwelling seasons (July-December). No direct correlation was found between sightings and the MEI. Sightings occurred more often than expected by chance during the peak upwelling months of August-November when the MEI was within one standard deviation of the average (binomial z=2.91, p<0.05). Sightings were spatially associated with areas of high chlorophyll a values (binomial z=4.46, p<0.05), pinniped rookeries (binomial z=6.03, p<0.05), and areas with high combined resource value (binomial z=5.36, p<0.05). The spatial distribution of sightings did not shift with seasonality, with the exception that sightings occurred less often than expected in areas of low combined resource value during the upwelling period (binomial z=-3.17, p<0.05). Though variability in observer effort should be considered when evaluating these data, these results do not suggest a strong pattern of seasonal occupancy or that killer whales are responsive to El Nino Southern Oscillation events. Further research is needed to determine if killer whales in the GMR comprise a single resident population, multiple resident and transient populations, or if killer whales observed in the GMR are part of a population inhabiting the eastern tropical Pacific region, which visit the area at various times. Advisors/Committee Members: Biggs, Douglas C. (advisor), Packard, Jane M. (advisor), Wursig, Bernd (committee member), Grant, William E. (committee member).

Subjects/Keywords: Killer whale; Galápagos, El Niño; Temporal; Spatial

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APA (6^th Edition):

Smith, K. (2012). Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11033

Chicago Manual of Style (16^th Edition):

Smith, Kerri. “Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador.” 2012. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11033.

MLA Handbook (7^th Edition):

Smith, Kerri. “Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador.” 2012. Web. 17 Jan 2021.

Vancouver:

Smith K. Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11033.

Council of Science Editors:

Smith K. Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11033

Texas A&M University

4. O'Hern, Julia. Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population.

Degree: PhD, Oceanography, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/148305

► Five line transect surveys for marine mammals were conducted offshore of mainland Ecuador and the Galápagos Islands from 2008-2011. These data were used in conjunction… (more)

▼ Five line transect surveys for marine mammals were conducted offshore of mainland Ecuador and the Galápagos Islands from 2008-2011. These data were used in conjunction with MODIS (Moderate Resolution Imaging Spectroradiometer) observations of ocean color and sea surface temperature (SST) to assess spatial and temporal relationships between surface oceanographic features and cetacean distribution within the Eastern Equatorial Pacific (EEP). Results from this study indicated that oceanographic processes affected cetacean distribution on inter-annual, seasonal, and weekly to monthly time scales. The spatial scales on which these processes affect cetacean distribution are small, the smallest associations being found at 4 km2 bin sizes, as well as 9 km2 and 36 km2 bin sizes. By utilizing ocean color and SST data from the MODIS instrument and analyzing variability of these parameters in addition to average concentration, cetacean distribution within the region was related to the locations of frontal boundaries. Cetaceans were grouped into two categories based on the trophic level and relative depths at which they forage. Cetaceans feeding nearer the ocean surface and lower on the trophic scale were generally found in cooler waters of higher average chlorophyll concentration and elevated variability. Those cetaceans feeding higher on the trophic scale and lower in the water column (mesopelagic and bathypelagic depths) were sighted within relatively warmer waters of reduced temperature variability near areas of high chlorophyll variability (though less variable and lower in average chlorophyll than surface feeding cetaceans), with little spatial and temporal lag between peak surface chlorophyll concentration and cetacean presence. The EEP is a biologically productive region with many competing economic and environmental interests. Ecuador is home to one of the largest artisenal fishing fleets in South America, and entanglement of various cetacean species has been a known issue for several decades (Félix and Haase, 2006; Castro and Rosero, 2010). Seismic exploration, shipping, and tourism are also found on the busy waterways surrounding both mainland Ecuador and the archipelago. The results of this study provide additional insight into the mesoscale processes affecting the distribution and habitat use of cetaceans within the EEP and South American waters and to support ongoing ecosystem management efforts. Advisors/Committee Members: Biggs, Douglas C (advisor), Mullin, Keith (committee member), Slowey, Niall (committee member), Filippi, Anthony (committee member), Würsig, Bernd (committee member).

Subjects/Keywords: equatorial Pacific; fronts; ocean color; Cetacean

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APA (6^th Edition):

O'Hern, J. (2012). Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/148305

Chicago Manual of Style (16^th Edition):

O'Hern, Julia. “Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population.” 2012. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/148305.

MLA Handbook (7^th Edition):

O'Hern, Julia. “Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population.” 2012. Web. 17 Jan 2021.

Vancouver:

O'Hern J. Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/148305.

Council of Science Editors:

O'Hern J. Cetacean Distribution in Ecuador: Spatial and Temporal Relationships between Ocean Fronts and the Apex Predator Population. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/148305

Texas A&M University

5. MacKay, Mithriel. Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA.

Degree: PhD, Marine Biology, 2015, Texas A&M University

URL: http://hdl.handle.net/1969.1/155581

► Occurrence patterns and social behaviors of North Atlantic humpback whales (Megaptera novaeangliae) (NAHW) wintering off Puerto Rico were investigated to examine the relationship of this… (more)

▼ Occurrence patterns and social behaviors of North Atlantic humpback whales (Megaptera novaeangliae) (NAHW) wintering off Puerto Rico were investigated to examine the relationship of this area to the aggregation wintering off the Dominican Republic. I described winter occurrence, movement and association patterns, and the relationship of group associations with bathymetric features in Mona Passage, immediately west of Puerto Rico. Data were collected from boat, land, and aerial surveys from 2011 to 2014. Acoustic data were collected with hydrophones deployed from a small vessel and units mounted to the sea floor, to determine the presence of singers (males). Photo-identification of individuals was used to describe intermixing of whales between higher latitudes and the study area. Social behaviors were described between intra- and inter-specific associations. A pilot study was conducted January-March 2011 from land platforms using scan sampling. In 2012, boat-based data collection and aerial reconnaissance were added. A total of 240.9 hours vessel, 13.0 hours aerial, and 303.6 hours land observations were conducted over 165 days. One hundred ninety-seven groups of humpback whales were observed with N = 331 individuals: 91 (46.2%) singletons, 67 (34%) dyads, 17 (8.6%) mother-calf pairs, 8 (4.1%) in competitive breeding groups, 8 (4.1%) mother-calf-escort groups, and 6 (3.1%) mixed-species associations. Group associations were not random. A multinomial linear regression model supported group composition and behaviors were correlated with “hotspots” associated with four bathymetric features. Dyads and surface active groups were dispersed among features in deeper water. Singletons were observed further from a shelf edge, while singing males were closely associated with a shelf edge. Mother-calf pairs occurred nearshore in shallow water moving offshore when accompanied by an escort. Identification photos matched against the NAHW catalog indicated movement between most feeding grounds and throughout the West Indies. It is important to continue and expand this study in Puerto Rico to monitor long-term population changes, and as a means of predicting where human activity overlaps with NAHW occurrence, especially due to possible U.S. delisting of NAHW as endangered. Advisors/Committee Members: Würsig, Bernd G (advisor), Rooker, Jay R (committee member), Biggs, Douglas C (committee member), Marshall, Christopher D (committee member), Pearson, Heidi C (committee member).

Subjects/Keywords: Humpback whale; Megaptera novaeangliea; Puerto Rico; North Atlantic; breeding grounds; habitat use; occurrence patterns; migration

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APA (6^th Edition):

MacKay, M. (2015). Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/155581

Chicago Manual of Style (16^th Edition):

MacKay, Mithriel. “Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA.” 2015. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/155581.

MLA Handbook (7^th Edition):

MacKay, Mithriel. “Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA.” 2015. Web. 17 Jan 2021.

Vancouver:

MacKay M. Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA. [Internet] [Doctoral dissertation]. Texas A&M University; 2015. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/155581.

Council of Science Editors:

MacKay M. Occurrence Patterns and Social Behaviors of Humpback Whales (Megaptera novaeangliae) Wintering off Puerto Rico, USA. [Doctoral Dissertation]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/155581

6. Drake, Aaron C. Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading.

Degree: MS, Ocean Engineering, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10095

► Extreme hurricane events of the past decade are responsible for several drag embedment anchor (DEA) mooring failures of mobile offshore drilling platforms stationed within the… (more)

▼ Extreme hurricane events of the past decade are responsible for several drag embedment anchor (DEA) mooring failures of mobile offshore drilling platforms stationed within the Gulf of Mexico. A proposed failure mechanism is caused by out-of-plane loading. The current status of DEA holding capacity is based on empirical design charts and does not include the effects of out-of-plane loading. Experimental modeling using a 1:10 scale generic DEA was performed at the Haynes Coastal Engineering Laboratory at Texas A & M University to examine the effects of out-of-plane load conditions. Instrumentation and specialized devices were constructed to measure the anchor's trajectory through a representative sample of Gulf of Mexico clay with average un-drained shear strength of 0.764 kPa (16 psf). The sediment basin allowed for drag distances of 4.87 m (16 ft) and an embedment depth of 1.37 m (4.5 ft). The measurements included pitch and roll of the anchor and line tension measured at the shank pad-eye. The variables modeled were fluke angle settings of 22°, 36° and 50°. The initial towline angle was varied from a minimum of 5° to upwards of 20°. Surface out-of-plane angles of 45° and 90° and embedment loading of 15°, 30° and 45° were examined. Curves of the ultimate holding capacity with respect to the out-of-plane towline angle and ultimate embedment depth were developed as functions of out-of-plane loading angles. Analysis of the rate effect indicates that a 46 percent increase in towing velocity causes an average 3 percent increase of holding capacity. The 50° fluke angle embeds an average of 0.7 fluke lengths deeper and has a holding capacity of 0.73 units greater than the 36° setting. The surface out-of-plane tests have a 5.1 percent reduction in holding capacity as the out-of-plane load angle increases from 45° to 90°. For all one fluke length initial towing distance tests, the ultimate holding capacity increases and the ultimate embedment depth decreases as the out-of-plane towing angle increases from 15° to 45°. The three fluke length initial towing distance tests indicate a contrasting trend, in that as the out-of-plane tow angle increases, both the ultimate holding capacity and ultimate embedment depth decrease. Advisors/Committee Members: Aubeny, Charles P. (advisor), Randall, Robert E. (advisor), Biggs, Douglas C. (committee member).

Subjects/Keywords: drag embedment anchors; DEA; model testing; In plane loading; out of plane loading; breakout

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APA (6^th Edition):

Drake, A. C. (2011). Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10095

Chicago Manual of Style (16^th Edition):

Drake, Aaron C. “Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading.” 2011. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10095.

MLA Handbook (7^th Edition):

Drake, Aaron C. “Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading.” 2011. Web. 17 Jan 2021.

Vancouver:

Drake AC. Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading. [Internet] [Masters thesis]. Texas A&M University; 2011. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10095.

Council of Science Editors:

Drake AC. Experimental Modeling and Laboratory Measurements of Drag Embedment Anchors Subjected to In-Plane and Out-Of-Plane Loading. [Masters Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10095

7. Lee, Olivia Astillero. Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia.

Degree: PhD, Wildlife and Fisheries Sciences, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9144

► I examined the population trends of northern fur seals (Callorhinus ursinus) using an age-specific metapopulation model that allowed migration between rookeries. Mortality and birth rates… (more)

▼ I examined the population trends of northern fur seals (Callorhinus ursinus) using an age-specific metapopulation model that allowed migration between rookeries. Mortality and birth rates were modified to simulate future population trends. I also examined the early migratory behavior and habitat associations of pups from Bering Island (BI), Russia. I instrumented 35 pups with Mk10-AL satellite tags and stomach temperature telemeters which provided diving, foraging and location data. I hypothesized that some aspects of pup behavior from the stable BI population differed from the behavior of pups from the unstable Pribilof Islands (PI). The population model revealed that emigration did not contribute significantly to the current PI population decline. However, large source populations contributed significantly to population growth in newly colonized rookeries. A stabilization of the PI population was predicted with a 10 to 20 percent reduction in both juvenile and adult female mortality rates. The diving behavior of pups showed a general progression towards longer and deeper dives as pups aged, particularly between 1600 – 0400 (local time), that was similar to PI pup behavior. However, unlike pups from the PI, I found three main diving strategies among BI pups: 1) shallow daytime divers (mean depth = 3.56 m), 2) deep daytime divers (mean depth = 6.36 m) and 3) mixed divers (mean depth = 4.81 m). The foraging behavior of pups showed that most successful ingestion events occurred between 1600 – 0400, with successful ingestion events lasting 25.36 plus/minus 27.37 min. There was no significant difference among the three strategies in the depth of successful foraging dives. I also examined the foraging search strategies in adult females and pups. Both pups and adults conducted Levy walks, although pups foraged in smaller patches (1 km scales). Using a logistic model to determine habitat associations, I found that pup locations were positively correlated with increasing chlorophyll a concentrations, distances from shore, and sea surface temperatures, and were negatively correlated with depth. There was no significant relationship between all pup locations and the regions (peripheries or centers) or types (cyclonic or anti-cyclonic) of eddies, but ingestion event locations were related to mesoscale eddy peripheries. Advisors/Committee Members: Davis, Randall (advisor), Wursig, Bernd (committee member), Gelwick, Frances (committee member), Biggs, Douglas (committee member).

Subjects/Keywords: northern fur seal pup; Callorhinus ursinus; foraging behavior; migration; diving behavior; population model; habitat

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APA (6^th Edition):

Lee, O. A. (2012). Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9144

Chicago Manual of Style (16^th Edition):

Lee, Olivia Astillero. “Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia.” 2012. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9144.

MLA Handbook (7^th Edition):

Lee, Olivia Astillero. “Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia.” 2012. Web. 17 Jan 2021.

Vancouver:

Lee OA. Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9144.

Council of Science Editors:

Lee OA. Early Migratory Behavior of Northern Fur Seal (Callorhinus ursinus) Pups from Bering Island, Russia. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9144

8. Horne, Courtney Leigh. Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico.

Degree: MS, Oceanography, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9057

► Mass coral spawning represents a nutrient input to coral reef systems that for Pacific reefs has been shown to stimulate pelagic and benthic processes. If… (more)

▼ Mass coral spawning represents a nutrient input to coral reef systems that for Pacific reefs has been shown to stimulate pelagic and benthic processes. If phytoplankton in the water column over the reef are able to utilize this annual nutrient input, this could potentially alter phytoplankton biomass and community composition, in what is normally a very oligotrophic system. Sampling was performed at East Flower Garden Bank (EFGB), Gulf of Mexico during May, July, and August 2009. The annual coral spawning event occurred there August 11-14, 2009. Samples were collected morning and evening at three depths and analyzed for nutrients, chlorophyll a, accessory pigments, phytoplankton species composition, and carbon, hydrogen, and nitrogen (CHN). During spawning, only small changes in nutrient concentrations were detected. Dissolved inorganic nitrogen (DIN) peaked on the second day of spawning and N:P ratio was highest on 5/28, likely due to particularly phosphate concentration. Chl a biomass was significantly different between sample dates and the biomass increased steadily throughout the spawning period. The contribution of different phytoplankton classes to total chlorophyll a was determined using known pigment algorithms. Prokaryotes were the dominant class across the entire sampling period with 60-80 percent abundance. Trichodesmium spp. was the dominant genus throughout the study and genus specific changes per sample date were seen. On 8/11 and 8/13 two genera contributed the majority of chl a (Trichodesmium spp. and Ceratium spp.; Cylindrotheca spp. and Trichodesmium spp., respectively). Abundance showed variability during spawning with a peak at 11 cells/ml on 8/12. The high abundance of Trichodesmium spp. could indicate N limitation is alleviated at the Flower Garden Banks (FGB). Current literature on coral spawning is limited to studies performed in the Great Barrier Reef, with assessment areas close to a major shoreline. Genera found at EFGB were similar to those found in other reef systems. It cannot be determined if nutrient input increased diversity, as diversity was high prior to spawning as well. Greater increase in available forms of nitrogen would have likely been found several days post major spawning. The FGB were a unique system to study, as they are coral reefs, but are located 200 km offshore. This study provided a snapshot into phytoplankton dynamics as a result of spawning. Changes across the short time scale were seen in biomass and community composition. Advisors/Committee Members: Rowe, Gilbert (advisor), Biggs, Douglas (committee member), Quigg, Antonietta (committee member).

Subjects/Keywords: Phytoplankton; coral spawning; Flower Garden Banks

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APA (6^th Edition):

Horne, C. L. (2012). Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9057

Chicago Manual of Style (16^th Edition):

Horne, Courtney Leigh. “Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico.” 2012. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9057.

MLA Handbook (7^th Edition):

Horne, Courtney Leigh. “Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico.” 2012. Web. 17 Jan 2021.

Vancouver:

Horne CL. Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9057.

Council of Science Editors:

Horne CL. Phytoplankton Responses to Mass Coral Spawning in the Flower Garden Banks, Gulf of Mexico. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9057

9. Adair, Robert Fletcher. Estimating production and cost for clamshell mechanical dredges.

Degree: MS, Ocean Engineering, 2005, Texas A&M University

URL: http://hdl.handle.net/1969.1/1536

► Clamshell dredges are used around the United States for both navigational and environmental dredging projects. Clamshell dredges are extremely mobile and can excavate sediment over… (more)

▼ Clamshell dredges are used around the United States for both navigational and environmental dredging projects. Clamshell dredges are extremely mobile and can excavate sediment over a wide range of depths. The object of this thesis is to develop a methodology for production and cost estimation for clamshell dredge projects. There are current methods of predicting clamshell dredge production which rely on production curves and constant cycle times. This thesis calculates production estimation by predicting cycle time which is the time required to complete one dredge cycle. By varying the cycle time according to site characteristics production can be predicted. A second important component to predicting clamshell dredge production is bucket fill factor. This is the percent of the bucket that will fill with sediment depending on the type of soil being excavated. Using cycle time as the basis for production calculation a spreadsheet has been created to simplify the calculation of production and project cost. The production calculation also factors in soil type and region of the United States. The spreadsheet is capable of operating with basic site characteristics, or with details about the dredge, bucket size, and region. Once the production is calculated the project cost can be determined. First the project length is found by dividing the total amount of sediment that is to be excavated by the production rate. Once the project length is calculated the remainder of the project cost can be found. The methods discussed in this thesis were used to calculate project cost for 5 different projects. The results were then compared to estimates by the government and the actual cost of the project. The government estimates were an average of 39% higher than the actual project cost. The method discussed in this thesis was only 6% higher than the actual cost. Advisors/Committee Members: Randall, Robert (advisor), Edge, Billy (committee member), Biggs, Douglas (committee member).

Subjects/Keywords: Mechanical; Clamshell; Dredge; Production; Cost

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APA (6^th Edition):

Adair, R. F. (2005). Estimating production and cost for clamshell mechanical dredges. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/1536

Chicago Manual of Style (16^th Edition):

Adair, Robert Fletcher. “Estimating production and cost for clamshell mechanical dredges.” 2005. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/1536.

MLA Handbook (7^th Edition):

Adair, Robert Fletcher. “Estimating production and cost for clamshell mechanical dredges.” 2005. Web. 17 Jan 2021.

Vancouver:

Adair RF. Estimating production and cost for clamshell mechanical dredges. [Internet] [Masters thesis]. Texas A&M University; 2005. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/1536.

Council of Science Editors:

Adair RF. Estimating production and cost for clamshell mechanical dredges. [Masters Thesis]. Texas A&M University; 2005. Available from: http://hdl.handle.net/1969.1/1536

10. Dahood, Adrian D. Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand.

Degree: MS, Wildlife and Fisheries Sciences, 2010, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-452

► In Kaikoura, New Zealand dusky dolphins (Lagenorhynchus obscurus) are economically and ecologically important. However, more information on key habitat requirements is needed to develop an… (more)

▼ In Kaikoura, New Zealand dusky dolphins (Lagenorhynchus obscurus) are economically and ecologically important. However, more information on key habitat requirements is needed to develop an effective management plan for them. I use systematic shore-based observations and tour operator gathered boat-based observations and review night-time foraging observations to explore dusky dolphin occurrence and movement patterns. I discuss possible influence of prey on these patterns. From January to December 2006, I conducted crepuscular observations from three clifftop stations. With these geospatial data I examined occurrence, mean speed, and linearity over seasonal, diel, and tidal temporal scales. From October 1995 to November 2006 tour guides recorded GPS locations for over 5,000 dusky dolphin groups, allowing me to examine seasonal occurrence patterns. For both datasets I quantified occurrence patterns relative to depth, distance from the Kaikoura Canyon, and distance from shore. I reviewed the three studies conducted on dusky night foraging behavior in Kaikoura. I explore the effects of seasonal and lunar-scale changes in night-time light levels on dusky dolphin foraging behavior. Duskies exhibited seasonal and diel, but not tidal occurrence and movement patterns. Dolphins were found farther offshore, in deeper water, and travelling faster in winter and approaching sunset. The areas of highest sightings density were associated with the Kaikoura Canyon, and shifted almost entirely into the canyon in winter and approaching sunset. Dolphins made sharper turns during summer. Dolphins were, on average, closer to the Kaikoura Canyon than to shore. Seasonal occurrence patterns described by tour operator data agreed with those described by geospatial data collected by shorebased observers. Duskies exhibited flexible foraging behavior and appeared to use both seasonal and lunar phase specific tactics. Night-time light levels appeared to influence dusky foraging behavior, possibly through changes in prey behavior. Prey availability and behavior patterns appeared to influence dusky occurrence and movement patterns. The dolphins' affinity for the Kaikoura Canyon may reflect a strategy to maximize access to prey. Advisors/Committee Members: Würsig, Bernd (advisor), Biggs, Douglas C. (committee member), Winemiller, Kirk O. (committee member).

Subjects/Keywords: Dolphin; Habitat Use; GIS; Night Foraging

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APA (6^th Edition):

Dahood, A. D. (2010). Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-452

Chicago Manual of Style (16^th Edition):

Dahood, Adrian D. “Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand.” 2010. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-452.

MLA Handbook (7^th Edition):

Dahood, Adrian D. “Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand.” 2010. Web. 17 Jan 2021.

Vancouver:

Dahood AD. Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand. [Internet] [Masters thesis]. Texas A&M University; 2010. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-452.

Council of Science Editors:

Dahood AD. Dusky dolphin (Lagenorhynchus obscurus) occurrence and movement patterns near Kaikoura, New Zealand. [Masters Thesis]. Texas A&M University; 2010. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-452

11. Duncan, Roxanne. Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools.

Degree: MS, Oceanography, 2012, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11881

► East Pacific green sea turtles, Chelonia mydas, play ecologically important roles in marine habitats which range from grazing (and thus regularly "mowing") algae and seagrass… (more)

▼ East Pacific green sea turtles, Chelonia mydas, play ecologically important roles in marine habitats which range from grazing (and thus regularly "mowing") algae and seagrass beds to cycling nutrients between the ocean and land. However, these important grazers have been hunted to ecological extinction in some places for their eggs, meat, and skin. The conservation initiative for the survival of sea turtles requires the protection of their primary habitats in conjunction with a decrease in their interaction with humans. One way these objectives can be met is through the creation of species distribution maps (SDMs). For this thesis, a SDM was created from a generalized additive model used to identify major feeding areas for East Pacific green turtles residing in the Galapagos Islands. The input for the model was green turtle sighting locations during a June 2010 marine life observation survey and remotely sensed values of four oceanographic parameters obtained from satellite sensors (Bathymetry, Sea Surface Temperature, Chlorophyll a, and Current Speed). Line transects of intertidal and subtidal shoreline regions of the islands of Isabela, San Cristobal, and Floreana were also completed, to describe similarities and differences in macroalgal abundance between the locations. A generalized additive model (GAM) explained 56% of the data's null deviance and had a true positive rate of 0.83. The corresponding species distribution map indicated that East Pacific green sea turtles prefer to forage in warm, low chlorophyll a, slow moving waters at depths mostly less than 250m throughout the archipelago. ANOVA analyses showed that macroalgal abundance was statistically different (p-value < 0.01) between the islands of San Cristobal and Isabela. The line transects analysis also documented that red algae was the most prominent phyla at the sites and that the macroalgal abundance did not vary much between months June 2010 and April/May 2011. With these results, potential foraging areas for East Pacific green turtles can be identified and protected. Future studies will be focused on the collection of macroalgae from coastal areas outlined in the SDM and the interactions between green turtles and their competitors and/or predators. This information can be used to validate the areas delineated by the model and to further the understanding of the spatial-temporal effects on macroalgal abundance. Advisors/Committee Members: Biggs, Douglas (advisor), DiMarco, Steven (committee member), Filippi, Anthony (committee member).

Subjects/Keywords: East Pacific Green Turtle; MGET; Galapagos Islands

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APA (6^th Edition):

Duncan, R. (2012). Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11881

Chicago Manual of Style (16^th Edition):

Duncan, Roxanne. “Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools.” 2012. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11881.

MLA Handbook (7^th Edition):

Duncan, Roxanne. “Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools.” 2012. Web. 17 Jan 2021.

Vancouver:

Duncan R. Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11881.

Council of Science Editors:

Duncan R. Development of a Species Distribution Model for the East Pacific Green Sea Turtle using Ecological Geoprocessing Tools. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11881

12. Olivier, Paul. Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia.

Degree: PhD, Marine Biology, 2015, Texas A&M University

URL: http://hdl.handle.net/1969.1/155177

► A key objective of the National Marine Fisheries Service recovery plan for Steller sea lions (SSL – Eumetopias jubatus) is to protect critical habitats. Doing… (more)

▼ A key objective of the National Marine Fisheries Service recovery plan for Steller sea lions (SSL – Eumetopias jubatus) is to protect critical habitats. Doing so relies in part on knowledge of SSL ecology based on time-depth data, at-sea dive locations and post-trip dietary analyses. I used data from animal-borne video and data recorders (VDRs) attached to lactating SSL at Lovushki Island, Russia to improve our knowledge by: 1) classifying dives based on three-dimensional swim paths and foraging success, 2) quantifying rates at which prey were encountered and consumed, and 3) testing whether a giving up rule, shown to be applicable to phocids, could similarly benefit SSL. I identified five dive types: shallow and deep foraging dives, opportunistic foraging dives, a group of unique dives with no consistent behaviors, and non-foraging dives. I found that discrimination between foraging and non-foraging dives was possible with time-depth data alone, but relied on the assumption that time spent swimming horizontally between the descent and ascent represented swimming at the seabed. I also concluded that SSL at Lovushki were consuming enough prey to satisfy their estimated nutritional requirements. To determine if lactating SSL at Lovushki Island could improve foraging success by incorporating a giving up rule into their foraging strategy I: 1) identified how dive duration varied according to foraging success and 2) constructed a simulation model to simulate the foraging behaviors and habitats of SSL. SSL did not appear to employ a giving up rule when foraging. This was supported by simulation results which showed that using a giving up rule may not allow SSL to markedly improve foraging success. My research provided the first descriptions of the submerged foraging behaviors of SSL derived from three-dimensional swim paths and video recorded observations of foraging success. Results improved our knowledge of how SSL utilize the marine resources available to them and demonstrated the benefits of deploying VDRs on SSL. VDR deployments at other locations would increase the geographic resolution at which protection measures could be designed by improving our ability to identify and protect resources based on local foraging behaviors and success rates. Advisors/Committee Members: Davis, Randall (advisor), Andrews, Russel (committee member), Biggs, Douglas (committee member), Grant, William (committee member), Wursig, Bernd (committee member).

Subjects/Keywords: Foraging; Ecology; Steller sea lion

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APA (6^th Edition):

Olivier, P. (2015). Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/155177

Chicago Manual of Style (16^th Edition):

Olivier, Paul. “Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia.” 2015. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/155177.

MLA Handbook (7^th Edition):

Olivier, Paul. “Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia.” 2015. Web. 17 Jan 2021.

Vancouver:

Olivier P. Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia. [Internet] [Doctoral dissertation]. Texas A&M University; 2015. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/155177.

Council of Science Editors:

Olivier P. Foraging Ecology of Lactating Steller Sea Lions (Eumetopias jubatus) at Lovushki Island, Russia. [Doctoral Dissertation]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/155177

13. Fletcher, William Wallerich. Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico.

Degree: MS, Oceanography, 2005, Texas A&M University

URL: http://hdl.handle.net/1969.1/2694

► During the Northeastern Gulf of Mexico Chemical and Hydrography study (NEGOM-COH), nine oceanographic cruises were fielded during the spring, summer and fall seasons from November… (more)

▼ During the Northeastern Gulf of Mexico Chemical and Hydrography study (NEGOM-COH), nine oceanographic cruises were fielded during the spring, summer and fall seasons from November 1997 to August 2000. Surface chlorophyll-? fluorescence, salinity, and temperature data were logged once a minute from the R/V Gyre and subsurface chlorophyll-? fluorescence, salinity, temperature, and nutrients were profiled when the ship stopped to make stations. Each cruise occupied 94-98 stations, partitioned among 11 cross-margin transects of water depths between 10 m to 1000 m. Overall chlorophyll-? abundance within the study area is forced by the amount of freshwater discharge. Seasonal and interannual differences are largely determined by the monthly mean streamflow for the major rivers within the NEGOM area, particularly the Mississippi River. However, an important forcing function for transport of river water to the outer continental shelf and slope is the periodic presence of anticyclonic slope eddies. Especially when these slope eddies were centered south and east of the Mississippi River delta, they entrained and so redistributed low salinity green water to a wider area within the NEGOM region than could be predicted by mean monthly streamflow alone. The mean surface chlorophyll-? concentrations, and in particular the distribution of relatively high surface chlorophyll-? concentrations off-shelf, were strongly dependent upon entrainment of freshwater by these slope eddies, especially during the three summer cruises. Interannual variability in the summertime entrainment of low salinity green water was driven by summer-to-summer differences in sea surface height (SSH) of the slope eddy(s), and in how far they extended on margin. Satellite observations of ocean color showed that freshwater entrainment by anticyclonic eddies persisted for a temporal scale of several weeks each summer. Satellite-derived surface chlorophyll-? concentrations were positively correlated with in situ measurements of surface chlorophyll-?, with greatest agreement between satellite and ship measurements of surface chlorophyll-? at concentrations <1.5 mg/m3. Because subsurface chlorophyll-? concentrations were often elevated at depths greater than the first optical depth, satellite measurements of chlorophyll-? concentration generally underestimated integrated chlorophyll-? standing stocks within the euphotic zone. Advisors/Committee Members: Biggs, Douglas C. (advisor), Guinasso, Norman L. (advisor), Roelke, Daniel L. (committee member), Pinckney, James L. (committee member).

Subjects/Keywords: chlorophyll; gulf of mexico; riverine input

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APA (6^th Edition):

Fletcher, W. W. (2005). Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/2694

Chicago Manual of Style (16^th Edition):

Fletcher, William Wallerich. “Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico.” 2005. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/2694.

MLA Handbook (7^th Edition):

Fletcher, William Wallerich. “Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico.” 2005. Web. 17 Jan 2021.

Vancouver:

Fletcher WW. Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico. [Internet] [Masters thesis]. Texas A&M University; 2005. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/2694.

Council of Science Editors:

Fletcher WW. Seasonal and interannual differences in surface chlorophyll stocks and integrated water column chlorophyll stocks in the northeastern Gulf of Mexico. [Masters Thesis]. Texas A&M University; 2005. Available from: http://hdl.handle.net/1969.1/2694

14. Kaltenberg, Amanda May. 38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico.

Degree: MS, Oceanography, 2005, Texas A&M University

URL: http://hdl.handle.net/1969.1/1387

► A hull-mounted 38-kHz phased-array acoustic Doppler current profiler (ADCP) was used to acoustically survey the continental margin of the northern Gulf of Mexico (GOM) during… (more)

▼ A hull-mounted 38-kHz phased-array acoustic Doppler current profiler (ADCP) was used to acoustically survey the continental margin of the northern Gulf of Mexico (GOM) during 6 cruises in 2002-2003. This is the first backscatter survey with a 38-kHz ADCP in the Gulf of Mexico. ADCPs have been used as a proxy to measure the volume backscatter return from plankton in the water column, however previous studies were restricted to the upper 200 to 300 meters due to the relatively high frequency of operation (150-300 kHz) of the transducers. In addition to measuring deep water current velocities, the 38-kHz phased-array ADCP can measure Relative Acoustic Backscatter Intensity (RABI) as deep as 1000 meters. The daytime depth of the main deep scattering layer at 400 to 500 meters was resolved, and locally high backscatter intensity can be seen down to 800 meters. The objectives were to determine how to analyze RABI from the instrument to resolve scattering layers, and then to seek secondary deep scattering layers of potential prey species below the main deep scattering layer, from 600 to 800 meters in the feeding range for Gulf of Mexico sperm whales. Based on RABI from the 38-kHz ADCP, secondary DSLs in sperm whale diving range were more commonly recorded over the continental shelf than in the deep basin region of the Gulf of Mexico. The daytime depths of migrating plankton showed variation depending on physical circulation features (cyclone, anticyclone, proximity to Mississippi river, and Loop Current) present. Vertical migrations compared between concurrently running 38 and 153-kHz ADCPs showed an overlap of acoustic scatterers recorded by the two instruments, however the 153-kHz instrument has much finer vertical resolution. Vertical migration rates were calculated and simultaneous net tow samples from one of the cruises was used to compare abundance estimates by the two methods. Advisors/Committee Members: Biggs, Douglas C. (advisor), DiMarco, Steven F. (advisor), Wormuth, John H. (committee member), Horning, Markus (committee member).

Subjects/Keywords: acoustic survey; acoustics; 38-kHz ADCP; ADCP; deep scattering layers; diel vertical migration; sperm whales

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APA (6^th Edition):

Kaltenberg, A. M. (2005). 38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/1387

Chicago Manual of Style (16^th Edition):

Kaltenberg, Amanda May. “38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico.” 2005. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/1387.

MLA Handbook (7^th Edition):

Kaltenberg, Amanda May. “38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico.” 2005. Web. 17 Jan 2021.

Vancouver:

Kaltenberg AM. 38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico. [Internet] [Masters thesis]. Texas A&M University; 2005. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/1387.

Council of Science Editors:

Kaltenberg AM. 38-kHz ADCP investigation of deep scattering layers in sperm whale habitat in the northern Gulf of Mexico. [Masters Thesis]. Texas A&M University; 2005. Available from: http://hdl.handle.net/1969.1/1387

15. Belonovich, Olga Andreevna. Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca).

Degree: PhD, Wildlife and Fisheries Sciences, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9320

► The northern fur seal (NFS) population on the Pribilof Islands (PI) is currently declining while the population on the Commander Islands (CI which includes Bering… (more)

▼ The northern fur seal (NFS) population on the Pribilof Islands (PI) is currently declining while the population on the Commander Islands (CI which includes Bering and Medny Islands) is stable. The reasons for the different population trajectories remain unknown. Comparing differences in behavioral ecology and predation pressure between these two populations could provide an explanation. This study examined lactating NFS female behavior to determine: 1) summer foraging patterns (trip duration, trip direction, dive depth) of animals from two nearby rookeries on Bering Island, 2) winter migration from Medny and Bering Islands relative to patterns of ocean productivity, and 3) the potential impact of killer whale predation on population dynamics. Data were collected from 2003 to 2010 using visual observations and telemetry. Twenty-one satellite transmitters, 29 time-depth recorders and 17 geolocation recorders were deployed. Shore-based observations of killer whale predation and photo-identification were conducted near the CI rookeries in 19992010. During lactation, both mean foraging trip duration and mean maximum diving depth (3.4 plus/minus 1.3 days and 17.7 plus/minus 6.8 m, respectively) for NFS adult females (n = 28) did not significantly change among years. Although foraging areas of NFS from the two rookeries on Bering Island overlapped, the mean direction of travel from Severo-Zapadnoe rookery was significantly (p<0.01) different compared with Severnoe rookery. The foraging patterns suggested that these females had a reliable food source that did not change despite potential environmental changes or the effects of fisheries. During their winter migration, NFS females from the CI traveled to the Transition Zone Chlorophyll Front (32° N-42° N) in the North Pacific Ocean. Their winter migration routes and the location of overwinter foraging areas were positively correlated with high ocean productivity (near surface chlorophyll a concentration). Over 82 percent (n=17) of these females spent 38 months near the eastern coast of Hokkaido, Japan and followed the coastal high productivity areas on their way back to the CI. Transient killer whales in groups of 2-12 individuals were repeatedly observed preying mostly on NFS males during the summer. The simulation model showed little impact on population dynamics as long as male fur seals were the primary prey. However, if the number of killer whales increased or they changed their diet to include females and pups, then the NFS population on the CI could decline. The winter migration of NFS from CI and PI are similar. Lactating NFS from the PI exhibit greater summer foraging effort (longer average trip duration and bout duration; greater number of deep dives) compared with females from the CI. Advisors/Committee Members: Davis, Randall (advisor), Würsig, Bernd (advisor), Grant, William (committee member), Packard, Jane (committee member), Biggs, Douglas (committee member), Andrews, Russel (committee member).

Subjects/Keywords: northern fur seals; telemetry; foraging trips; winter migrations; killer whales predation; the Commander Islands

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APA (6^th Edition):

Belonovich, O. A. (2011). Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca). (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9320

Chicago Manual of Style (16^th Edition):

Belonovich, Olga Andreevna. “Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca).” 2011. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9320.

MLA Handbook (7^th Edition):

Belonovich, Olga Andreevna. “Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca).” 2011. Web. 17 Jan 2021.

Vancouver:

Belonovich OA. Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca). [Internet] [Doctoral dissertation]. Texas A&M University; 2011. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9320.

Council of Science Editors:

Belonovich OA. Northern Fur Seals (Callorhinus ursinus) of the Commander Islands: Summer Feeding Trips, Winter Migrations and Interactions with Killer Whales (Orcinus orca). [Doctoral Dissertation]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9320

Texas A&M University

16. Lundquist, David Jeffrey. Behavior and movement of southern right whales: effects of boats and swimmers.

Degree: MS, Wildlife and Fisheries Sciences, 2007, Texas A&M University

URL: http://hdl.handle.net/1969.1/5909

► Guidelines for sustainable swim-with tourism for large whales are not welldeveloped, as researchers have focused on delphinids. Nations that signed the Convention on Biological Diversity… (more)

▼ Guidelines for sustainable swim-with tourism for large whales are not welldeveloped, as researchers have focused on delphinids. Nations that signed the Convention on Biological Diversity at the Earth Summit in Rio de Janeiro in 1992 are obligated to consider sustainable use principles when allowing new ecotourism activities, yet the fast-growing worldwide swim-with-whales industry is lacking the research needed to create successful management guidelines that can be implemented by local communities. From September to November of 2005 and July to October of 2006, I collected movement and behavioral state data for southern right whales in proximity of swimmers at PenÃÂnsula ValdÃÂ©s, Argentina. Whales were observed before, during, and after a series of directed interactions with swimmers. I quantified the behavioral and movement effects relative to group composition of whales (mother/calf pairs, juveniles or adult/mixed groups) and activity level of swimmers. Group composition had a significant effect on the response of whales to swimmers. Swimmer activity level did not substantially affect the reaction of whales. Resting and socializing activities significantly decreased and traveling activities significantly increased when boats approached and when swimmers entered the water. Resting and socializing bout length in the presence of swimmers decreased to less than a third of the length of bouts when swimmers were not present. Whales swam faster, reoriented more often, and followed a less linear path during interactions. Effects were greater for mother/calf pairs than juveniles, while mixed adult/juvenile groups showed no significant changes in behavior or movement. The initial reaction of whales to the approach of the boat and the entry of swimmers into the water was a good predictor of the magnitude of effects on the behavior and movement patterns of the whale. Increased levels of activity are a concern for the whales that are resting and not feeding in this area. To provide quality resource management guidelines for this activity, additional research is needed to determine long-term effects of boat and swimmer activities on the behavior of whales. It is also important to obtain energetic data for right whales to determine the magnitude of impacts. Advisors/Committee Members: Wursig, Bernd (advisor), Biggs, Douglas (committee member), Davis, Randall (committee member).

Subjects/Keywords: Southern Right Whale; Tourism; swim-with-whale; Eubalaena australis; Peninsula Valdes; whalewatching

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lundquist, D. J. (2007). Behavior and movement of southern right whales: effects of boats and swimmers. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/5909

Chicago Manual of Style (16^th Edition):

Lundquist, David Jeffrey. “Behavior and movement of southern right whales: effects of boats and swimmers.” 2007. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/5909.

MLA Handbook (7^th Edition):

Lundquist, David Jeffrey. “Behavior and movement of southern right whales: effects of boats and swimmers.” 2007. Web. 17 Jan 2021.

Vancouver:

Lundquist DJ. Behavior and movement of southern right whales: effects of boats and swimmers. [Internet] [Masters thesis]. Texas A&M University; 2007. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/5909.

Council of Science Editors:

Lundquist DJ. Behavior and movement of southern right whales: effects of boats and swimmers. [Masters Thesis]. Texas A&M University; 2007. Available from: http://hdl.handle.net/1969.1/5909

Texas A&M University

17. Azzara, Alyson Julie. Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior.

Degree: MS, Oceanography, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-1173

► This research was carried out in support of fieldwork in the Gulf of Mexico in summers 2004 and 2005 as part of the multidisciplinary Sperm… (more)

▼ This research was carried out in support of fieldwork in the Gulf of Mexico in summers 2004 and 2005 as part of the multidisciplinary Sperm Whale Seismic Study (SWSS). Important aspects of SWSS research include oceanographic habitat characterization and studies of sperm whale foraging and diving patterns. During the SWSS 2005 cruise, acoustic volume backscatter data were collected using a 38 kHz ADCP for comparison with XBT, MODIS ocean color data, and whale dive profiles extrapolated from analysis of towed passive acoustic hydrophone array recordings of whale vocalizations. This unique data set, collected from a cyclonic eddy, was compared with non-upwelling conditions surveyed in the western Gulf and the Mississippi Canyon in summer 2004. My focus was to examine the relationship between acoustic backscatter intensity from the deep scattering layer (DSL; usually 400-600 m deep) and the depths to which whales dived. The results of the study investigate differences in DSL characteristics between divergent zones and non-divergent zones, and examine connections relating to variations in sperm whale dive patterns. The analysis of 38 kHz ADCP data showed that there were significant differences in some characteristics of the main DSL dependent on time of day. There were no significant differences in characteristics of the main DSL between divergent and non-divergent areas or between 2004 and 2005. The comparison of the 38 kHz ADCP and the 70 kHz Simrad echosounder data yielded a relationship of 4 ADCP counts for every 1 dB of Sv. This relationship was a promising start to a potential calibration for the ADCP instrument. Lastly, the analysis of localized sperm whale dive profiles identified three basic dive profiles; Deep (> 800 m), Mid-water dives to DSL depths (500 - 800 m) and Shallow (<500 m). The analysis also showed that whale dive behavior did not change based on time of day or location. It showed that whales are diving above the DSL as well as through and below, however these dives are independent of differences in DSL characteristics. Advisors/Committee Members: Biggs, Douglas (advisor), DiMarco, Steven (advisor), Quigg, Antonietta (committee member), Thode, Aaron (committee member).

Subjects/Keywords: Deep scattering layer; Gulf of Mexico; Sperm Whale

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Azzara, A. J. (2009). Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1173

Chicago Manual of Style (16^th Edition):

Azzara, Alyson Julie. “Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior.” 2009. Masters Thesis, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-1173.

MLA Handbook (7^th Edition):

Azzara, Alyson Julie. “Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior.” 2009. Web. 17 Jan 2021.

Vancouver:

Azzara AJ. Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior. [Internet] [Masters thesis]. Texas A&M University; 2009. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1173.

Council of Science Editors:

Azzara AJ. Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior. [Masters Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1173

Texas A&M University

18. Soliman, Yousria Soliman. Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants.

Degree: PhD, Oceanography, 2009, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-1356

► In five summer cruises during the period 2000-2004, seventy-four box cores were collected from eleven locations from the Mississippi Canyon (480- 2750m, northern Gulf of… (more)

▼ In five summer cruises during the period 2000-2004, seventy-four box cores were collected from eleven locations from the Mississippi Canyon (480- 2750m, northern Gulf of Mexico), and an adjacent transect (336-2920) to understand the community structure and trophic function of amphipods and for measuring the bioaccumulation of polycyclic aromatic hydrocarbons, (PAHs). Amphipods were discovered to be an important component of the macrofauna of the Mississippi Canyon (40 % of the total faunal abundance). Seventy two species, belonging to nineteen families, were collected from the study area with 61 species from the canyon and only 38 species from the non-Canyon transect. The head of the canyon (480m) was dominated by dense mats (15,880 ind/m2) of a new amphipod (Ampelisca mississippiana). The logarithm of the amphipod abundance decreased linearly with depth. The species diversity (H`) exhibited a parabolic pattern with a maximum at 1100m. The differences in amphipod abundances and biodiversities were correlated with the variation in the amount of available organic matter. The depression in diversity in the canyon head is thought to be competitive exclusion resulting from the dominance by A.mississippiana, but the high species richness is presumed to be a function of the structural complexity of the canyon. Annual secondary production of A. mississippiana was 6.93 g dry wt m-2, based on size-frequency method and corresponding to an estimated univoltine generation from a regression model. The production/biomass ratio (P/B) was 3.11. Production of this magnitude is comparable to shallow marine ampeliscids but are high for the depauperate northern Gulf of Mexico. The effect of the organic contaminants and the bioavailability to the amphipods was determined through measuring the bioaccumulation of the PAHs. The distribution of PAHs in sediments was different from the distribution in the organisms suggesting preferential uptake/depuration or uptake from pore or bottom waters. The average bioaccumulation factor (4.36 ± 2.55) and the biota sediment accumulation factor (0.24±0.13) for the total PAHs by the ampeliscids were within the range reported for other benthic invertebrates. The average bioaccumulation factors were highest for dibenzothiophenes (up to 132) and alkylated PAHs and lowest for parent high molecular weight PAHs. Advisors/Committee Members: Rowe, Gilbert T (advisor), Wade, Terry L. (advisor), Wicksten, Mary K. (committee member), Biggs, Douglas C. (committee member).

Subjects/Keywords: Organic; Canyon; Amphipods

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Soliman, Y. S. (2009). Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1356

Chicago Manual of Style (16^th Edition):

Soliman, Yousria Soliman. “Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants.” 2009. Doctoral Dissertation, Texas A&M University. Accessed January 17, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-1356.

MLA Handbook (7^th Edition):

Soliman, Yousria Soliman. “Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants.” 2009. Web. 17 Jan 2021.

Vancouver:

Soliman YS. Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1356.

Council of Science Editors:

Soliman YS. Amphipods of the deep Mississippi Canyon, northern Gulf of Mexico: ecology and bioaccumulation of organic contaminants. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1356

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