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Natanson L.J.,National Oceanic and Atmospheric Administration | Adams D.H.,Florida Fish And Wildlife Conservation Commission | Winton M.V.,Coonamessett Farm Foundation | Maurer J.R.,Kachemak Bay Research Reserve
Transactions of the American Fisheries Society | Year: 2014

Age and growth estimates for the Bull Shark Carcharhinus leucas were derived from 121 vertebral centra collected from Bull Sharks (59.1-223.5 cm FL) between 1966 and 2010 in the western North Atlantic Ocean. Size at birth was confirmed with an additional 20 embryos (44.2-54.4 cm FL). The maximum age based on vertebral band pair counts was 25 (184 cm FL) and 27 (196 cm FL) years for males and females, respectively. The logistic and Gompertz growth models fitted the size-at-age data best for males and females, respectively. Based on previously published estimates of length at maturity, males mature at 15-17 years (176-185 cm FL) and females at 15 years (189 cm FL). Bull Sharks in the western North Atlantic Ocean and the Gulf of Mexico have similar growth rates and reach similar sizes at age. © American Fisheries Society 2014.

Grimm C.,Roger Williams University | Huntsberger C.,Coonamessett Farm Foundation | Markey K.,Roger Williams University | Inglis S.,University of Massachusetts Dartmouth | Smolowitz R.,Roger Williams University
Diseases of Aquatic Organisms | Year: 2016

The Atlantic sea scallop Placopecten magellanicus is an economically important species in the offshore fisheries on the east coast of the USA. Recently, animals collected from waters ranging from Massachusetts to Maryland have shown variably sized (up to 1 cm in diameter) orange nodular foci, predominantly in the adductor muscle tissue, but also in other organs. Histological evaluation of the nodular lesions showed rod-shaped bacteria that stain acid-fast positive and Gram-positive. PCR methodology was employed to identify the causative organism of the nodules as a Mycobacterium sp. using analysis of the partial 16S gene and the 16S-23S internal transcribed spacer region. Based upon genotypic findings, the causative bacterium fits well into the genus Mycobacterium. © Inter-Research 2016.

Patel S.H.,Drexel University | Morreale S.J.,Cornell University | Panagopoulou A.,ARCHELON | Bailey H.,University of Maryland Center for Environmental science | And 4 more authors.
Ecosphere | Year: 2015

While telemetry is an invaluable tool for tracking animal movement patterns, the data generated by this technique is often challenging to interpret. Here, we addressed this issue by developing a novel method, based on changepoint analysis, which incorporated both the horizontal and vertical movement metrics and compared this output to that from a switching state-space model (SSSM) that categorized behavior based on horizontal movement metrics. We deployed 20 satellite transmitters on postnesting loggerhead turtles at Rethymno, Crete, Greece between 2010 and 2011 to monitor their at-sea behavior. We used both models to identify behavioral changes, such as the switches from migration to foraging, and from foraging to overwintering. The satellite-tracked turtles exhibited three discrete migratory strategies, with 9 turtles migrating southwards to the coast of northern Africa, 6 turtles migrating northwards into the Aegean Sea, and 4 turtles remaining resident in the waters of Crete. The SSSM readily identified the switch from transiting to ARS behavior in most animals, but the CPA model was able to distinguish multiple modes and more subtle shifts in behavior corresponding with shifts from migration to foraging to overwintering behaviors. We have shown that by incorporating vertical movement metrics into the analysis of telemetry data, previously hidden shifts in behavior can be revealed. The resulting increase in ability to discern complex behavioral patterns of animals remotely will likely yield better management and conservation decisions for a wide array of organisms. © 2015 Patel et al.

Ceriani S.A.,Florida Fish And Wildlife Conservation Commission | Roth J.D.,University of Manitoba | Sasso C.R.,National Oceanic and Atmospheric Administration | McClellan C.M.,University of Exeter | And 10 more authors.
Ecosphere | Year: 2014

Stable isotope analysis can be used to infer geospatial linkages of highly migratory species. Identifying foraging grounds of marine organisms from their isotopic signatures is becoming de rigueur as it has been with terrestrial organisms. Sea turtles are being increasingly studied using a combination of satellite telemetry and stable isotope analysis; these studies along with those from other charismatic, highly vagile, and widely distributed species (e.g., tuna, billfish, sharks, dolphins, whales) have the potential to yield large datasets to develop methodologies to decipher migratory pathways in the marine realm. We collected tissue samples (epidermis and red blood cells) for carbon (δ13C) and nitrogen ((δ15N) stable isotope analysis from 214 individual loggerheads (Caretta caretta) in the Northwest Atlantic Ocean (NWA). We used discriminant function analysis (DFA) to examine how well δ13C and (δ15N classify loggerhead foraging areas. The DFA model was derived from isotopic signatures of 58 loggerheads equipped with satellite tags to identify foraging locations. We assessed model accuracy with the remaining 156 untracked loggerheads that were captured at their foraging locations. The DFA model correctly identified the foraging ground of 93.0% of individuals with a probability greater than 66.7%. The results of the external validation (1) confirm that assignment models based on tracked loggerheads in the NWA are robust and (2) provide the first independent evidence supporting the use of these models for migratory marine organisms. Additionally, we used these data to generate loggerhead-specific δ13C and (δ15N isoscapes, the first for a predator in the Atlantic Ocean. We found a latitudinal trend of δ13C values with higher values in the southern region (20-25°N) and a more complex pattern with (δ15N, with intermediate latitudes (30-35°N) near large coastal estuaries having higher (δ15N-enrichment. These results indicate that this method with further refinement may provide a viable, more spatially-explicit option for identifying loggerhead foraging grounds. Copyright: © 2014 Ceriani et al.

Siemann L.A.,Coonamessett Farm Foundation | Parkins C.J.,Coonamessett Farm Foundation | Smolowitz R.J.,Coonamessett Farm Foundation
ICES Journal of Marine Science | Year: 2015

Quantifying the distribution and abundance of the Atlantic sea scallop (Placopecten magellanicus) is a fishery management priority, and stock assessments increasingly rely on video surveys. Interpreting the results of these surveys requires understanding the inherent biases introduced as a result of target animal behaviour. Our study investigated the effect of artificial lights on the behaviour of Atlantic sea scallops during a video survey using a towed benthic sled. Swimming and stationary scallopswere counted in survey videos using event logging software. In addition, the locations, orientations, and swimming directions of the scallopswere noted in a subset of the videos. The proportion of scallops that swamwhen an artificial lightwas turned onwas significantly smaller than the proportion thatswamwhenthe lightwas off. Further analysis using a logistic model showed that only light state (off or on) predicted the likelihood of scallop swimming responses. Possible reasons for this unexpected behaviour are discussed, with a focus on the scallop visual system. © 2015 International Council for the Exploration of the Sea. All rights reserved.

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