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Assessments of fisheries by‐catch on marine megafauna are important for developing effective management strategies. For sea turtles, impacts may be evident in nesting population trends, but generally only after a lag, as turtles are slow to mature. We examined 850 loggerhead turtle (Caretta caretta) by‐catch samples collected over 14 years throughout the western North Atlantic to identify source nesting populations. We identified proportions of turtles from 19 distinct management units (MUs), using mitochondrial DNA and mixed stock analysis, considering population size. We found a significant split in the distribution of small versus large loggerheads to the north and south of Cape Hatteras, North Carolina (latitude 35°N). North of Cape Hatteras, large turtles came from south‐east Florida (SEFL; 44% ± 15%) and the northern United States (33% ± 16%) MUs, while south of Cape Hatteras, the major contributors were Central East Florida (52% ± 20%) and south‐east Florida (SEFL; 41% ± 20%). Small turtles in the north came from Central East Florida (64% ± 14%), and in the south, south‐east Florida had the highest representation (56% ± 25%). There was little contribution from Mediterranean and Cape Verde populations, indicating low risk from western North Atlantic by‐catch to MUs in the Mediterranean. Understanding where threats may impact source populations is important, particularly for larger size turtles, as these individuals have the highest reproductive value. These findings allow more informed threat assessments to be conducted for loggerhead turtles considering spatial and demographic structure.

Although sea turtles have received substantial focus worldwide, research on the immature life stages is still relatively limited. The latter is of particular importance, given that a large proportion of sea turtle populations comprises immature individuals. We set out to identify knowledge gaps and identify the main barriers hindering research in this field. We analyzed the perceptions of sea turtle experts through an online survey which gathered their opinions on the current state of affairs on immature sea turtle research, including species and regions in need of further study, priority research questions, and barriers that have interfered with the advancement of research. Our gap analysis indicates that studies on immature leatherback Dermochelys coriacea and hawksbill Eretmochelys imbricata turtles are lacking, as are studies on all species based in the Indian, South Pacific, and South Atlantic Oceans. Experts also perceived that studies in population ecology, namely on survivorship and demography, and habitat use/behavior, are needed to advance the state of knowledge on immature sea turtles. Our survey findings indicate the need for more interdisciplinary research, collaborative efforts (e.g. data-sharing, joint field activities), and improved communication among researchers, funding bodies, stakeholders, and decision-makers. Fil: Wildermann, Natalie E.. Florida State University; Estados Unidos Fil: Gredzens, Christian. Florida State University; Estados Unidos Fil: Avens, Larisa. National Ocean And Atmospheric Administration; Estados Unidos Fil: Barrios Garrido, Héctor A.. Universidad del Zulia; Venezuela. Florida State University; Estados Unidos Fil: Bell, Ian. Aquatic Species Program. Conservation And Biodiversity Operations Branch; Australia Fil: Blumenthal, Janice. Cayman Islands Department Of Environment; Islas Caimán Fil: Bolten, Alan B.. University of Florida; Estados Unidos Fil: McNeill, Joanne Braun. National Ocean And Atmospheric Administration; Estados Unidos Fil: Casale, Paolo. Università degli Studi di Pisa; Italia Fil: Di Domenico, Maikon. Universidade Federal do Paraná; Brasil Fil: Domit, Camila. Universidade Federal do Paraná; Brasil Fil: Epperly, Sheryan P.. National Ocean And Atmospheric Administration; Estados Unidos Fil: Godfrey, Matthew H.. North Carolina Wildlife Resources Commission; Estados Unidos. University of North Carolina; Estados Unidos. University of Duke; Estados Unidos Fil: Godley, Brendan J.. University of Exeter; Reino Unido Fil: González Carman, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Hamann, Mark. James Cook University; Australia Fil: Hart, Kristen M.. United States Geological Survey; Estados Unidos Fil: Ishihara, Takashi. Sea Turtle Association of Japan; Japón. Suma Aqualife Park; Japón Fil: Mansfield, Kate L.. University Of Central Florida; Estados Unidos Fil: Metz, Tasha L.. No especifica; Fil: Miller, Jeffrey D.. No especifica; Fil: Pilcher, Nicolas J.. Marine Research Foundation; Malasia Fil: Read, Mark A.. Great Barrier Reef Marine Park Authority; Australia Fil: Sasso, Christopher. National Ocean And Atmospheric Administration; Estados Unidos Fil: Seminoff, Jeffrey A.. National Ocean And Atmospheric Administration; Estados Unidos Fil: Seney, Erin E.. University Of Central Florida; Estados Unidos Fil: Williard, Amanda Southwood. University of North Carolina; Estados Unidos Fil: Tomás, Jesús. Universidad de Valencia; España Fil: Vélez Rubio, Gabriela M.. Universidad de la República; Uruguay. Karumbé Ngo; Uruguay Fil: Ware, Matthew. Florida State University; Estados Unidos Fil: Jessica L. Williams. Tartarugas para o Amanhã; Mozambique Fil: Wyneken, Jeanette. Florida Atlantic University; Estados Unidos Fil: Fuentes, Mariana M. P. B. Florida State University; Estados Unidos

Fisheries that operate at large spatial scales and with high intensity have the potential to impact highly migratory species, and it is important to characterize threats to specific breeding populations of these species. We used many‐to‐many mixed‐stock analysis (MSA) (n = 408) and microsatellite assignment testing (n = 397) to determine source populations for leatherback turtles (Dermochelys coriacea) caught as bycatch in the U.S. pelagic longline fishery from 2002 to 2012 in the western North Atlantic. Within the United States, we had bycatch samples from the majority of statistical fishing areas: Gulf of Mexico (GOM), Northeast Distant (NED), Caribbean (CAR), Florida East Coast (FEC), Mid Atlantic Bight (MAB), Northeast Coastal (NEC), South Atlantic Bight (SAB) and Sargasso (SAR). We determined the proportions of turtles from each of nine nesting stocks in the Atlantic in each of the sampled areas. These nesting stocks included Brazil, Costa Rica, Florida, Trinidad, French Guiana, St. Croix, Ghana, Gabon, and South Africa. The MSA revealed that the NED had a lower relative proportion of turtles from Costa Rica than other areas and that the GOM had the highest relative proportion of turtles from Costa Rica. No turtles were assigned to the African rookeries, lending further evidence that turtles from that region forage elsewhere and therefore may not be affected by western North Atlantic fisheries. This work contributes to the ongoing assessment of threats to leatherback turtles in the Regional Management Unit (RMU) of the western North Atlantic, and draws attention to the disproportionate number of turtles from Costa Rica being caught in the Gulf of Mexico; Costa Rica is one of the only populations in the northern Atlantic that is not experiencing significant increases in nest numbers. This approach should be useful in determining population‐specific threats to other highly migratory protected species that may depend on segregated foraging areas either within or among species.

Circle hooks have become a standard requirement in many commercial longline fisheries in the united states, and are used increasingly worldwide. Circle hooks, when compared to J-hooks, are thought to reduce bycatch without significantly decreasing (and possibly increasing) catch of most target species. Circle hook offset and baiting technique are also thought to influence bycatch and mortality of species of concern, such as sea turtles and billfishes. We compared non-offset circle hooks to those with a 10° offset and single or threaded baiting techniques in the united states atlantic and gulf of mexico pelagic longline fishery. Offset and/or baiting techniques were compared within sets targeting one of three species independently: swordfish, Xiphias gladius linnaeus, 1758, yellowfin tuna, Thunnus albacares (bonnaterre, 1788), and bigeye tuna, Thunnus obesus (lowe, 1839). Most comparisons of catch and bycatch did not differ between gears or techniques. In swordfish-directed sets, we found a 46% decline in catch of atlantic sailfish when using 18/0 non-offset circle hooks single baited with mackerel compared to 18/0 10° offset circle hooks with threaded mackerel. In yellowfin tuna sets, single baiting significantly decreased target catch by 22% and escolar catch by 28%, compared to threaded baiting. We detected no significant effect of any of the offset or baiting treatments on the bycatch of sea turtles and most other species of concern due to the rarity of capture events. We conclude, in part, that bycatch mitigation research in other fisheries with larger detrimental population level impacts to species of concern may potentially yield greater conservation benefits.

Research was conducted in 2002 and 2003 by noaa's national Marine fisheries service, southeast fisheries science center, to investigate changes in hook design and bait type to reduce the bycatch of sea turtles on pelagic longlines in the western north atlantic ocean. The effectiveness of 18/0-20/0 circle hooks and 10/0 Japanese tuna hooks with squid (Illex spp.) and mackerel bait (Scomber scombrus linnaeus, 1758) was evaluated against the industry standard 9/0 J-hooks with squid bait with respect to reducing sea turtle and shark interactions while maintaining swordfish (Xiphias gladius linnaeus, 1758) and tuna (Thunnus spp.) catch rates. In total, 973,734 hooks were deployed during the study. Individually, circle hooks and mackerel bait significantly reduced both loggerhead [Caretta caretta (linnaeus, 1758)] and leatherback [Dermochelys coriacea (vandelli, 1761)] sea turtle bycatch. The combination of 18/0 circle hooks with mackerel bait was even more effective for loggerhead sea turtles and had a significant increase in swordfish catch by weight. The combination 18/0 circle hooks with squid bait resulted in a significant decrease in the swordfish catch and a significant increase in the catch rate of blue shark [Prionace glauca (linnaeus, 1758)] , bluefin tuna [Thunnus thynnus (linnaeus, 1758)], and albacore tuna [Thunnus alalunga (bonnaterre, 1788)]. With all hook types, mackerel bait resulted in a significant decrease in blue shark, bigeye tuna [Thunnus obesus (lowe, 1839)], and albacore tuna, but significantly increased the catch of porbeagle [Lamna nasus (bonnaterre, 1788)] and shortfin mako (Isurus oxyrinchus rafinesque, 1810).

Experiments were conducted on the grand Banks of the north Atlantic ocean during 2002-2003 to evaluate the effect of circle hooks and mackerel bait on pelagic longline catches and bycatch, and compare the treatments to the industry standards at the time. Circle hooks were 18/0, and both non-offset and 10° offset were used as separate treatments and compared to the 9/0 J-hook control hooks with 10°-30° offset. Bait treatment was mackerel (Scomber scombrus linnaeus, 1758), which was compared to the squid control (Illex spp.). We analyzed the effects of hook (one J- and two circle hooks), bait (mackerel and squid), temperature, soak time, and animal length on anatomical hooking location for seven fish species and two sea turtle species. We also analyzed the effects of the same variables, inclusive and exclusive of hooking location, on the odds of boating a dead fish. We found that hook was one of the most important variables in predicting anatomical hooking location, and that soak time and hook and/or anatomical hooking location were important in predicting the odds of observing a dead animal boatside. The importance of the other variables differed by species, and for several species no models were significant for predicting hooking location or for predicting observed mortality.

Because incidental capture in pelagic longline fishing gear potentially kills or injures thousands of sea turtles annually, solutions to reduce the frequency and mortality rate of these interactions are critical conservation priorities. Understanding factors that affect post-hooking mortality rates remains an important component to evaluating the population-level impact of these interactions. Post-release mortality may be dependent upon the nature of the interaction (hooking location and/or entanglement) and amount of gear remaining at release. Hooking location can impact the ability of the crew to remove gear, as deeply ingested hooks cannot be removed safely. We examined the effects of hook type (circle vs J-hooks), offset (degrees), and other factors on hooking location in leatherback, Dermochelys coriacea (Vandelli, 1761), and loggerhead, Caretta caretta (linnaeus, 1758), sea turtles incidentally captured from 2000 to 2010 using fishery observer data. Significant differences in hooking location in loggerheads were observed between offset J-hooks and non-offset and 10° offset circle hooks; loggerheads were most often mouth/beak hooked with circle hooks, whereas most had swallowed offset J-hooks. Greater offsets appear to increase the frequency of deeply ingested hooks. Leatherback sea turtles were predominately externally hooked regardless of hook type, but mouth hookings occurred significantly more often on non-offset (0°) circle and J-hooks than on 10° offset circle hooks. When combined with outreach and education on careful release protocols, the use of circle hooks may increase post-interaction survival by modifying hooking location and facilitating maximum gear removal.

Loggerhead sea turtles Caretta caretta have been listed as threatened under the US Endangered Species Act since 1978, and a change in their listing status to endangered was recently under consideration. Estimates of adult population size are needed to evaluate population status, but include a number of uncertainties. A point estimate of loggerhead population size based on a nest count fails to convey the range of our uncertainty in the estimated number of indi- viduals in a population. We developed distributions of adult female loggerhead subpopulation sizes for 5 subpopulations of the western North Atlantic, and for the western North Atlantic popu- lation as a whole. Distributions were derived by re-sampling from available nest counts (2001�2010) and data on breeding interval, survival and clutch frequency, each affecting the extrapolation of nest numbers to adult females. Our best estimate for the western North Atlantic adult female loggerhead population was 38 334 (SD = 2287) adult females. Confidence limits on estimates for the individual subpopulations ranged from a high of 45 058 adult females for Penin- sular Florida to a low of 258 adult females in the Dry Tortugas. To reduce uncertainty in population estimates, research needs to focus on quantifying breeding interval and clutch frequency, espe- cially in the less-studied subpopulations.

Declines in sea turtle populations worldwide have been attributed in part to incidental capture in hook and line fisheries. Methods to reduce turtle bycatch and mortality must strike a bal- ance between bycatch reduction and target species retention if they are to gain acceptance from fish- ers. To investigate potential bycatch reduction measures, we examined the effects of hook size, bait type, baiting technique, and animal size on the frequency of loggerhead sea turtles Caretta caretta ingesting a baited hook during controlled trials. Results indicated that as hook size increased, the likelihood for deep ingestion decreased. Smaller turtles were less likely to swallow larger hooks. Tur- tles were less likely to swallow hooks baited with sardines than with squid and single-baited rather than threaded baits. Results are likely due to differences in bait texture, hook shielding effects, and turtles' behavioral differences. We suggest that fishing with large hooks, using finfish instead of squid, and using single-baited instead of threaded baits might reduce deep ingestion rates of hooks by loggerheads as large as 65 cm in standard straight carapace length (notch to tip).

Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water tem- perature, region, bottom depth, and target species are all significant predictors of the number of log- gerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit.

Sea turtles captured in pound nets during the autumn and early winter in the Pamlico- Albermarle Estuarine Complex, North Carolina, USA, were sampled 1995-1997 and 2001-2003 to monitor trends in catch rates during their autumn emigration from the temperate sounds. Juvenile loggerhead turtles Caretta caretta were the most frequent species encountered, followed by green turtles Chelonia mydas and Kemp's ridley turtles Lepidochelys kempii. Several different subpopula- tions with origins throughout the western North Atlantic were represented on these foraging grounds. The catch rates of loggerhead turtles increased significantly at a rate of 13% yr -1 . Despite annual increases in the major contributing nesting beach populations in excess of 10% yr -1 , we did not detect a trend in catch rates for either green or Kemp's ridley turtles, perhaps due to low statisti- cal power. There was a significant increase in size of loggerhead turtles over time. We also detected a significant difference in annual size distributions of green and Kemp's ridley sea turtles, but there was no discernable pattern. We conclude that long-term studies on the sea turtles' foraging grounds, at multiple sites, are needed to monitor the status of sea turtle populations.

Because sex is determined by incubation temperatures in sea turtles and immature animals are not sexually dimorphic externally, circulating levels of testosterone measured with radioimmunoassay (RIA), in conjunction with laparoscopies, have been used to estimate sex ratios. From September to December 1995 to 1997, and from June to December 1998 to 2002, we sampled blood from 1106 juvenile loggerhead sea turtles (Caretta caretta) incidentally captured in pound nets set in Core and Pamlico Sounds, North Carolina to measure testosterone levels. Laparoscopies of 89 of these turtles revealed a sex ratio of 2.1F:1M, similar to other juvenile loggerhead populations along the southeastern coast of the USA. Laparoscopies demonstrated that testosterone levels correctly identified males during summer months (water temperatures .23 C), but were unreliable during late autumn/winter months (water temperatures #16 C). During the summer months, females (n 5 201) exhibited testosterone concentrations with an upper limit of 239.0 pg/ml, and males (n 5 69) exhibited a lower limit of 372.0 pg/ml, for a sex ratio of 2.9F:1.0M. We recommend that verification of the RIA should be conducted by laparoscoping a subset of turtles sampled in all sex ratio studies. In addition, this verification should be conducted at several different times throughout the year to evaluate any possible seasonal effects on testosterone concentrations.

We estimated summer abundance of juvenile Loggerhead Turtles at our study site in Core Sound, NC with a Horvitz-Thompson type estimator, which uses count data and recapture probability to estimate abundance. Abundance ranged from 192 (95% CI = 88–1047) to 633 (95% CI = 219–1047) turtles over the six years of this study. These results provide preliminary estimates of juvenile Loggerhead Turtle abundance during the summer in Core Sound.

The sex of young sea turtles is difficult to determine because they lack externally dimorphic characteristics and heteromorphic sex chromosomes, yet internal dimorphic morphology is defined at hatching. We tested the reliability of nine internal gonad and accessory duct characteristics to identify the sex of 558 posthatchling loggerhead sea turtles accurately. We modified existing laparoscopic procedures, previously used to classify the sex of larger sea turtles and other turtle species, for use in posthatchlings. Here we describe our approach and quantify the reliability of our morphological criteria. Sex was verified by histological examination of gonadal biopsies from a subset of the turtles. We noted seasonal shifts in early gonadal structure so that some characters which were reliable in the summer and fall were not reliable other times of the year. Thus, we confined the analysis to the six characters that were reliable year round: gonad shape, paramesonephric duct size, gonad size, paramesonephric duct lumen presence, paramesonephric duct mobility, and gonad attachment. Using discriminant analyses of the biopsy and morphological data, we found high correlations between sex from tissue biopsies and these six morphological characters; this analysis misclassified just 2% of the animals with histological verification. Applying the classification functions to animals without histology and comparing those results to our visual classification resulted in 2% reclassification. The analysis reclassified animals that we or the histology correctly identified that had both female-like and male-like characters. Our method provided accurate identification of sex in very young sea turtles. This methodology enables sex ratio assessments in early life stages, which are critical to species recovery efforts. Additionally, sex assignment data are basic to our understanding of patterns and processes directing dimorphic changes of the gonads and their ducts.

Population growth and annual survival of juvenile loggerhead turtles Caretta caretta were investigated in North Carolina using mark-recapture techniques. Lack of fit of the models employed caused us to reject the obtained estimates and led us to suspect that many loggerhead turtles were transient in the study area. We estimated apparent survival and the proportions of residents and transients. Transients represented approximately 75% of newly captured individuals captured at our study site. When transients were taken into account, apparent survival of residents increased from between 0.36 and 0.74 to 0.81. Our study highlights the need to consider the presence of transients when interpreting the results of loggerhead monitoring studies.

Although significant amounts of research have been dedicated to increasing the knowledge of the life history of green turtles (Chelonia mydas), large gaps exist in our understanding of juvenile migratory behavior. These gaps can be filled by genetic studies of foraging ground aggregations. Using mitochondrial DNA markers and Bayesian analyses, samples (n = 106) from a foraging aggregation in North Carolina indicated that animals from the east coast of the United States (54%) and Mexico (27%) dominate the composition with the remainder coming from other Caribbean and Atlantic nesting aggregations. These findings prompted a reanalysis of 4 regional foraging aggregations using Bayesian mixed stock analysis, analysis of molecular variance, and diversity measures. Significant regional population structure between northern and southern foraging aggregations in the Caribbean was detected (phiST = 0.27, P = 0.000) in addition to significant nesting aggregation structure (phiST = 0.87, P = 0.000). Haplotype diversity levels were highest at foraging aggregations located within the confluence of major current systems. These findings indicate that both currents and behavior have strong influences on the composition of foraging aggregations. In addition, our results provide evidence of juvenile homing to regional foraging grounds and highlight the difficulties of separating historical and current effects on recruitment patterns at foraging locations.

Health status of a total of 57 loggerhead sea turtles (Caretta caretta; 42 migratory and 15 residential turtles) was analyzed using body condition and hematologic parameters. A subset of 18 juvenile migratory loggerhead sea turtles in the fall of 1997 and 15 residential turtles in the summer of 2000 were analyzed for barnacle epibiota. The migratory group had significantly higher red blood cell counts and percent heterophils and significantly lower percent lymphocyte and absolute eosinophil counts, as well as significantly lower plasma concentrations of calcium, sodium, chloride, potassium, glucose, alkaline phosphatase, and anion gap. Many of these variations may be because of physiology of migration. A positive association between turtle weight and hematocrit was detected and may be because of larger turtles diving for longer periods of time. There were no significant differences of epibiota load, health of the turtles, or condition index between turtles captured during the two events.

Changes in hook design and bait type were investigated as measures to reduce the bycatch of sea turtles on pelagic longlines in the western North Atlantic Ocean. Specifically, the effectiveness of 18/0 circle hooks and mackerel (Scomber scombrus) bait was evaluated with respect to reducing sea turtle interactions and maintaining swordfish (Xiphias gladius) and tuna (Thunnus spp.) catch rates. Individually, circle hooks and mackerel bait significantly reduced both loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtle bycatch. Circle hooks also significantly reduced the rate of hook ingestion by the loggerheads, potentially reducing postrelease mortality. The combination of circle hooks and mackerel bait was even more effective for loggerhead turtles and had no negative effect on swordfish catch. These modifications in fishing methods, in conjunction with tools developed to remove hooks and line from the turtles, significantly reduced the capture rate of sea turtles and potentially the post-hooking mortality of those that were caught and did not negatively impact the primary target species catch rate. In addition, these mitigation measures have the potential to reduce mortality of sea turtles and other bycatch species worldwide.

Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (ΦST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats.

Genetic markers have proven useful for determining which sea turtle rookeries contribute to a particular feeding ground. This information is especially relevant when management concerns include anthropogenic mortality of feeding cohorts, and the suspected presence of endangered populations. One such feeding habitat is the Pamlico–Albemarle Estuarine Complex in North Carolina, which was established as an index area in 1995 to monitor population-specific recovery of sea turtles. Pound nets in the study area were surveyed at random from September–December (1995–1997) to enumerate incidental captures of sea turtles as an index of sea turtle abundance. In this study, we estimated the rookery origins of this feeding cohort using both maximum likelihood and Bayesian based stock analysis programs and compare and contrast these different methodologies. The Bayesian methods appear to yield more realistic estimates of percent contribution to the feeding cohort when information regarding relative population sizes was used. Subsequently, we tested for temporal variation in the frequency of mitochondrial DNA haplotypes and resulting estimates of contribution over a 3-year time span. Mixed stock analysis of the combined data indicated that 80 of the individuals originated from the south Florida nesting population, 12 were from the northeast Florida to North Carolina nesting population, 6 from Yucatan, Mexico, and 2 from other rookeries. Although statistically significant shifts in haplotype frequencies were not observed between the three annual sampling periods, estimates of composition indicated subtle differences in the contributions to this foraging area over the sampling period.

To investigate site fidelity and homing behavior in juvenile loggerheads (Caretta caretta, L.), a mark-recapture study spanning four years (1998–2001) was conducted in Core Sound, N.C., USA. Each year of the study, approximately half of the turtles captured were tagged and released near the capture sites (n=207), while the remaining turtles were displaced 15–20 km and released (n=198). Loggerheads in both groups were recaptured in equal proportions near the original capture sites and many individuals were also recaptured in subsequent years. These data imply that juvenile loggerheads often returned to their capture sites following displacement, because if turtles dispersed randomly or remained near their release sites, then fewer displaced turtles should have been caught again. Moreover, because turtles migrate out of North Carolina sounds each winter, turtles recaptured at the same locations in different years evidently returned to specific sites following long migrations. To further investigate homing behavior, a small number of displaced turtles (n=28) were tracked using radio telemetry following their release. Although transmitters detached from most turtles within a few days, analyses of initial headings showed strong orientation in the direction of the capture site. In addition, four turtles successfully tracked for longer periods of time all returned rapidly to the vicinity of the capture location and remained in the area. Taken together, the results of this study indicate that juvenile loggerheads exhibit fidelity to specific areas during summer months and possess the navigational abilities to home to these areas following forced displacements and long-distance migrations.

The risk of mortality to sea turtles with increasing trawl tow time was assessed in two seasons, summer and winter. Tows of 10 min or less had negligible mortality in both seasons while intermediate tow times resulted in rapid escalations in mortality before reaching a plateau of high mortality. Mortality increased more quickly in winter than in summer.

A directional sonic telemetry system in small embayment, seagrass, and channel habitats in Core Sound, North Carolina was evaluated. We compared point location estimates calculated after correcting for system bias in three different ways: using test station (i.e. known location transmitting–receiving stations) angle errors, and using a within test site and an among test site mean angle error estimate. Estimates are necessary because, when tracking an animal, system bias cannot be corrected for using test station angle errors. In addition, telemetered animals may move beyond test areas or into different habitats. We found no significant difference (P>0.05) among point location estimates, suggesting that a within or an among mean angle error was an acceptable estimate. Choosing the appropriate angle error estimate must be done carefully because both presented limitations. A within test site mean angle error was the more conservative approach, avoiding biases caused by significant (P 97% of the seagrass habitat in Core Sound. Although the majority (80%) of the polygons are small (

Until the turn of the century the inshore waters of North Carolina harbored populations of sea turtles large enough to support a commercial fishery. Based on a 4- to-5-year record of sighting reports by the public, interviews of recreational fishermen, and records kept by commercial fishermen the waters continue to provide important developmental habitats for loggerhead, green, and Kemp's ridley sea turtles. Leathertback and hawksbill sea turtles infrequently entered the inshore waters. Reports from the public and commercial fishermen indicated that sea turtles were present offshore North Carolina all year and were present in inshore waters April through December. Sea turtles were encountered most frequently in the Atlantic Ocean, but seasonal encounters in some inshore waters, such as Core and Pamlico Sounds, often were greater. In early May large numbers of leatherbacks were sighted in the ocean and moved northward along the beach. Reported sightings of leatherbacks declined markedly by late June. Based on incidental captures by commercial fishermen loggerhead turtles were the most numerous species in Pamlico and Core Sounds (80%), followed by green (15%) and Kemp's ridley sea turtles (5%). Most captured turtles were immature, and all were released alive. The abundance of immature sea turtles in North Carolina inshore waters serves to emphasize that southeast U.S. estuaries are important habitats for these threatened and endangered species. This recognition supported the decision of the U.S. National Marine Fisheries Service to extend the requirement for turtle excluder devices in shrimp trawls to inshore areas during the entire year, full implementation of these requirements was achieved by December 1994. Las aguas costeras de Carolina del Norte (EEUU) acogieron poblaciones de tortugas marinas lo suficientemente grandes como para sostener una pesqueria comercial hasta principios de siglo. Basados en 4 a 5 anos de registros de reportes de avistamiento por et publico, entrevistas a pescadores deportivos, y registros mantenidos por pescadores comerciales, es posible inferir que las aguas continuan proveyendo importantes habitats de desarrollo para las tortugas marinas cahuama, verde y lora de Kemp. Las tortugas marinas laud y de carey entraron en las aguas costeras en forma poco frecuente. Los reportes del publico y pescadores comerciales indicaron que las tortugas marinas estaban presentes en las aguas de alta mar frente a las costas de Carolina del Norte todo et ano y se encontraban en las aguas costeras entre abril y diciembre. Las tortugas fueron encontradas mas frecuentemente en et Oceano Atlantico, pero los encuentros estacionales en algunas aguas costeras, tales como los Estrechos de Core y Pamlico, fueron en muchos casos, mayores. A principios de Mayo se avistaron grandes numeros de tortugas laud en el oceano las cuales se movian en direcion al norte a lo largo de la costa. Los avistamientos de tortugas laud reportados declinaron marcadamente hacia finales de Junto. En base a las capturas incidentales por pesqueros comerciales se puede inferir que las tortugas cahuama fue la especie mas abundante en los Estrechos de Pamlico y Core (80%), seguidas de las tortugas verdes (15%) y las tortugas loras de Kemp (5%). La mayoŕia de las tortugas capturadas eran inmaduras y todas fueron liberadas con vida. La abundancia de tortugas marinas inmaduras en las aguas consteras de Carolina del Norte sirven para enfatizar que los estuarios del sudeste de los Estados Unidos son habitats importantes para estas especies amenazadas y en peligro. Estos reconocimientos fundamentaron la decision de extender el requerimiento de dispositivos de exclusion de tortugas en la pesca de arrastre del langostino hacia las areas costeras todo el ano; una implementacion completa de estos requerimientos fue alcanzada en diciembre de 1994.

Over the past 3 decades, the status of sea turtles and the need for their protection to aid population recovery have increasingly captured the interest of government agencies, non-governmental organisations (NGOs) and the general public worldwide. This interest has been matched by increased research attention, focusing on a wide variety of topics relating to sea turtle biology and ecology, together with the interrelations of sea turtles with the physical and natural environments. Although sea turtles have been better studied than most other marine fauna, management actions and their evaluation are often hindered by the lack of data on turtle biology, human-turtle interactions, turtle population status and threats. In an effort to inform effective sea turtle conservation a list of priority research questions was assembled based on the opinions of 35 sea turtle researchers from 13 nations working in fields related to turtle biology and/or conservation. The combined experience of the contributing researchers spanned the globe as well as many relevant disciplines involved in conservation research. An initial list of more than 200 questions gathered from respondents was condensed into 20 metaquestions and classified under 5 categories: reproductive biology, biogeography, population ecology, threats and conservation strategies. © Inter-Research 2010.

As sea turtles migrate along the Atlantic coast of the USA, their incidental capture in fisheries is a significant source of mortality. Because distribution of marine cheloniid turtles appears to be related, in part, to sea surface temperature (SST), the ability to predict water temperature over the continental shelf could be useful in minimizing turtle-fishery interactions. We analyzed 10 yr of advanced very high resolution radiometer (AVHRR) SST imagery to estimate the proportion of 18 spatial zones, nearshore and offshore of Hatteras, North Carolina, USA (35° N), to north of Cape Sable, Nova Scotia (44° N), at temperatures >10 to 15°C, by week. Detailed examples for 11°C, the temperature employed by some management actions in the study area, and for 14°C, the lowest tem- perature at which turtles were sighted by some studies in the area, demonstrate a predictable pattern of rapid warming in March and April, followed by rapid cooling in October and November, with nearshore waters warming more rapidly than those offshore. Of those loggerhead turtles Caretta caretta that stranded, were sighted, or were incidentally captured between Cape Hatteras, North Carolina, and Cape Cod, Massachusetts, those at lower latitudes occurred when 25% or more of the area reached a water temperature of 11°C, while those in the northern zones did not occur until 50% or more of the area had reached a water temperature of 14°C. This analysis provides a means of pre- dicting marine cheloniid turtle presence, which can be helpful in regulating fisheries that seasonally interact with turtles.

We evaluated accuracy and precision of a directional sonic telemetry system and 2 positioning systems to study sea turtle (Cheloniidae) use of estuarine habitat in Core Sound, North Carolina. Accuracy and precision of location estimates affect the power of statistical tests for use of habitat studies and define the amount of movement that can be reliably measured. Angle errors associated with the sonic system averaged −2.5° ± 5.67 (SD) for a 95% error arc of ± 11.34° (range −17−12°). We obtained 45 location estimates after correcting 90 bearings for bias. Location errors (E), obtained from stationary positions at 400-1,200 m, ranged from 14.6 to 281.0 m with a median of 75.6 m. The 90 and 95% confidence areas for these data were 11.1 and 21.2 ha, respectively. Location error varied (P < 0.01) WITH GEOMETRIC MEAN DISTANCE (D g ) between receivers and transmitters. Areal measures of confidence obtained at the D g 500-600 m were the smallest (2.1-2.8 ha) among 3 distance intervals within 500-1,200 m. Attained levels of accuracy and precision were adequate to determine turtle movement and distribution in relation to selected fisheries activities, but of limited value for use of habitat studies. Inaccurate position estimates of monitoring platforms (e.g., boats) also affect location estimates. Precision of position estimates of a stationary boat anchored at a known location (i.e., channel marker) were poor, averaging 62 m, when obtained from Long Range Navigation System (LORAN). In contrast, positions obtained from Differential Global Positioning System (DGPS) varied by 3 m. The DGPS did not affect (P = 0.94) location estimation. Average difference between estimates using known location coordinates and those obtained from DGPS was 0.56 with a 95% confidence interval of ± 1.29 m. We recommend that DGPS be used when evaluating sea turtle use of habitat. The DGPS was more accurate than LORAN and was unaffected by geography

We have examined the relationship between the abundance of juvenile spot {Leiostomas xanthurus) in the nursery areas along the western boundary of Pamlico Sound, North Carolina, and the circulation patterns in the Sound. Juvenile fish abundance data are related to wind measurements taken two to three weeks prior to the fish sampling program. When the wind has a significant eastward component, i.e., from the nursery areas toward the inlets during the period preceding the sampling program, juvenile spot are relatively abundant compared with periods when the wind is not in that direction. Our numerical model of circulation in Pamlico Sound indicates that this wind field produces surface currents towards the east, and near-bottom currents towards the nursery areas, i.e., towards the west. The near-bottom currents are driven by the pressure-gradient forces associated with the set up of sealevel in the down-wind direction. It is postulated that the bottom-seeking juvenile spot ride these favorable bottom currents across the sound from the inlets to the nursery areas.

Sea turtle populations disperse widely across oceans and migrate between terrestrial nesting habitat and distant feeding and developmental habitats. Understanding population stock structure is important for accurately assessing threats such as mortality from fishery bycatch and for defining specific demographic units of conservation concern. We compared 775 bp mtDNA control region haplotypes from 389 juvenile loggerhead turtles sampled as bycatch in the US pelagic longline fishery in the western North Atlantic Northeast Distant (NED) region to haplo- type frequencies observed in 23 genetically distinct nesting stocks representing the 4 distinct pop- ulation segments (DPSs) that have been identified throughout the Atlantic Ocean and Mediterran- ean Sea. We used Bayesian mixed-stock analysis to produce stock composition estimates for juvenile loggerhead turtles that use pelagic habitat in the central North Atlantic. We found that nearly all of the loggerheads caught in NED waters belonged to the Northwest Atlantic DPS (mean = 99.2%), with the majority coming from the large eastern Florida rookeries (mean = 84.0%). We also detected contributions from the western Florida rookeries (mean = 11.7%) and Mexico (mean = 3.5%) but found little evidence of contributions from the rookeries of the South Atlantic, Northeast Atlantic, or Mediterranean DPSs. These results will help improve specific threat assessments and are relevant to ongoing development of conservation plans that are aligned to the recent DPS listings for loggerheads.

Since the 1950’s the population structure of the Atlantic menhaden,Brevoortia tyrannus, has undergone dramatic changes. High rates of fishery exploitation during the 1960’s resulted in a drastic decline in the breadth of the age structure and numbers of spawning aged fish. The stock recovered under continued exploitation during the 1970’s in spite of these unfavorable conditions. Hence, the length and age at first spawning, the seasons and areas of spawning, and the potential number of ova produced as a function of length were reexamined during the 1978, 1979, and 1981 fishing seasons. No changes were detected in the reproductive biology of Atlantic menhaden. The size at first spawning, areas, and season of spawning were similar to results of previous studies. The minimum fork length of potential spawners was 180 mm. Few age-1 fish were mature but most females were mature at age-2. Analysis of the ovaries collected along the coast indicated some spawning occurred in the spring, a limited amount occurred in the summer, and most spawning occurred during the fall and winter. There was high intra-and interyear variability in the relationship between length and potential number of ova produced, and regression coefficients encompassed values from two previous studies, each based on a single fishing year. Data from this and the previous studies were combined and equally weighted to generate a representative predictive equation for the potential number of ova spawned as a function of length: eggs = 2563e0.0150(FL).