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Full-Text Articles in Life Sciences
Photo-Identification Methods Reveal Seasonal And Long-Term Site-Fidelity Of Risso’S Dolphins (Grampus Griseus) In Shallow Waters (Cardigan Bay, Wales), Marijke N. De Boer, Josephine Clark, Mardik F. Leopold, Mark P. Simmonds, Peter J.H. Reijnders
Photo-Identification Methods Reveal Seasonal And Long-Term Site-Fidelity Of Risso’S Dolphins (Grampus Griseus) In Shallow Waters (Cardigan Bay, Wales), Marijke N. De Boer, Josephine Clark, Mardik F. Leopold, Mark P. Simmonds, Peter J.H. Reijnders
Mark P. Simmonds, OBE
A photo-identification study on Risso’s dolphins was carried out off Bardsey Island in Wales (July to September, 1997-2007). Their local abundance was estimated using two different analytical techniques: 1) mark-recapture of well-marked dolphins using a “closed-population” model; and 2) a census technique based on the total number of iden-tified individual dolphins sighted over the study period. The mark-recapture estimates of 121 (left sides; 64 - 178, 95% CI; CV 0.24) and 145 dolphins (right sides; 78 - 213, 95% CI; CV 0.24) closely matched the census technique estimates (population size of 90 - 151). It was found that the dolphins …
Interactions Between Short-Beaked Common Dolphin (Delphinus Delphis) And The Winter Pelagic Pair-Trawl Fishery Ff Southwest England (Uk), Marijke N. De Boer, James T. Saulino, Mardik F. Leopold, Peter J.H. Reijnders, Mark P. Simmonds
Interactions Between Short-Beaked Common Dolphin (Delphinus Delphis) And The Winter Pelagic Pair-Trawl Fishery Ff Southwest England (Uk), Marijke N. De Boer, James T. Saulino, Mardik F. Leopold, Peter J.H. Reijnders, Mark P. Simmonds
Mark P. Simmonds, OBE
During offshore and onshore studies (2004 to 2009), the interactions between pair-trawls and short-beaked common dolphins (Delphinus delphis) were studied to better understand the impact of bycatch. A ‘hotspot’ area where pair-trawls overlapped with high dolphin abundance was identified. We made comparisons between boat-based data collected in absence and presence of pair-trawlers. The relative abundance and group-size of dolphins was significantly higher in the presence of pair-trawlers. Dolphins were observed associating with towing and hauling procedures. Significantly, more carcasses occurred in areas with hauling-activity than those without. Body-temperatures obtained from carcasses found near operating pair-trawlers indicated that bycatch mostly occurred …
Seagrasses In The Age Of Sea Turtle Conservation And Shark Overfishing, Michael Heithaus, Teresa Alcoverro, Rohan Arthur, Derek A. Burkholder, Kathryn A. Coates, Marjolijn J. A. Christianen, Nachiket Kelkar, Sarah A. Manuel, Aaron Wirsing, W. Judson Kenworthy, James W. Fourqurean
Seagrasses In The Age Of Sea Turtle Conservation And Shark Overfishing, Michael Heithaus, Teresa Alcoverro, Rohan Arthur, Derek A. Burkholder, Kathryn A. Coates, Marjolijn J. A. Christianen, Nachiket Kelkar, Sarah A. Manuel, Aaron Wirsing, W. Judson Kenworthy, James W. Fourqurean
HCAS Student Articles
Efforts to conserve globally declining herbivorous green sea turtles have resulted in promising growth of some populations. These trends could significantly impact critical ecosystem services provided by seagrass meadows on which turtles feed. Expanding turtle populations could improve seagrass ecosystem health by removing seagrass biomass and preventing of the formation of sediment anoxia. However, overfishing of large sharks, the primary green turtle predators, could facilitate turtle populations growing beyond historical sizes and trigger detrimental ecosystem impacts mirroring those on land when top predators were extirpated. Experimental data from multiple ocean basins suggest that increasing turtle populations can negatively impact seagrasses, …
A Mitogenomics View Of The Population Structure And Evolutionary History Of The Basking Shark Cetorhinus Maximum, Kimberly A. Finnegan
A Mitogenomics View Of The Population Structure And Evolutionary History Of The Basking Shark Cetorhinus Maximum, Kimberly A. Finnegan
HCNSO Student Theses and Dissertations
The basking shark, Cetorhinus maximus, has historically been a target of international fisheries, leading to well-documented declines in parts of its global distribution. Currently, the basking shark is listed as globally ‘Vulnerable’ and regionally ‘Endangered’ (North Pacific and Northeast Atlantic) on the IUCN Red List of Threatened Species, rendering the species an international conservation priority. Here, we assessed the global matrilineal genetic population structure and evolutionary history of the basking shark by completing the first whole mitochondrial genome sequence level survey of animals sampled from three globally widespread geographic regions: the western North Atlantic (n = 11), the …
Global Population Structure Of The Dusky Shark And Geographic Sourcing Of Shark Fins From Commercial Markets, Teagen K. Gray
Global Population Structure Of The Dusky Shark And Geographic Sourcing Of Shark Fins From Commercial Markets, Teagen K. Gray
HCNSO Student Theses and Dissertations
The dusky shark, Carcharinus obscurus, is a globally distributed, coastal-pelagic species subject to an apparent high level of exploitation. The International Union for the Conservation of Nature (IUCN) lists this species as “Vulnerable” globally, and “Endangered” within western North Atlantic and Gulf of Mexico waters due to an over 80% decline in this region, with no evidence of population recovery. The extensive exploitation of dusky sharks may partly be attributed to the high market value of its fins, but the contribution of individual dusky shark stocks to the fin markets is unknown. This knowledge would be helpful to detect …
Molecular Ecology Of Globally Distributed Sharks, Christine B. Testerman
Molecular Ecology Of Globally Distributed Sharks, Christine B. Testerman
HCNSO Student Theses and Dissertations
Many sharks have life history characteristics (e.g., slow growth, late age at maturity, low fecundity, and long gestation periods) that make their populations vulnerable to collapse due to overfishing. The porbeagle (Lamna nasus), bull shark (Carcharhinus leucas), great hammerhead (Sphyrna mokarran), and smooth hammerhead (S. zygaena), are all commercially exploited. The population genetic structure of these species was assessed based on globally distributed sample sets using mitochondrial control region (mtCR) sequences and/or nuclear markers. Complex patterns of evolutionary and demographic history were inferred using coalescent and statistical moment-based methods. All four species showed …
Concordance Between Phylogeographic And Biogeographic Boundaries In The Coral Triangle: Conservation Implications Based On Comparative Analyses Of Multiple Giant Clam Species, Timery S. Deboer, Maria Rio Abdon Naguit, Mark V. Erdmann, Maria Carmen A. Ablan-Lagman, Ambariyanto, Kent E. Carpenter, Abdul Hamid A. Toha, Paul H. Barber
Concordance Between Phylogeographic And Biogeographic Boundaries In The Coral Triangle: Conservation Implications Based On Comparative Analyses Of Multiple Giant Clam Species, Timery S. Deboer, Maria Rio Abdon Naguit, Mark V. Erdmann, Maria Carmen A. Ablan-Lagman, Ambariyanto, Kent E. Carpenter, Abdul Hamid A. Toha, Paul H. Barber
Biological Sciences Faculty Publications
Marine habitats are in decline worldwide, precipitating a strong interest in marine conservation. The use of biogeographic data to designate ecoregions has had significant impacts on terrestrial conservation efforts. However, classification of marine environments into ecoregions has only become available in the last several years, based on biogeographic data supplemented by geomorphology, ocean currents, and water temperatures. Here we use a comparative phylogeographic approach to test for concordant phylogeographic patterns in three closely related species of Tridacna giant clams across the Coral Triangle, the most biodiverse marine region in the world and one of the most threatened. Data from a …