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Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.

Sea turtle bycatch in commercial fisheries is a serious global problem. An estimated 250,000 loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles are taken each year as incidental catch by the pelagic longline fishing industry. Studies have examined various deterrents for their potential to repel sea turtles from the vicinity of fishing operations; visual deterrents such as shark models/silhouettes and gillnet illumination have shown the most promise. However, given the difficulty of directly observing sea turtle behavior in the wild, laboratory trials are crucial for characterizing the sea turtle response to shark models. The present study examined the response of 42 captive-reared juvenile loggerhead sea turtles to a shark model in a controlled laboratory setting. Loggerheads exhibited defensive behavior toward the shark model, taking significantly more time to bite squid bait beneath the shark model than that for squid beneath a control object (sphere) and bare squid...

The in-water status of green turtles (Chelonia mydas) in the northwestern Gulf of Mexico has received comparatively little attention in the management and conservation of this species in US waters. We addressed this void via entanglement netting surveys at 3 estuarine areas (Lavaca-Matagorda Bay, the Aransas Bay complex, and the lower Laguna Madre [LLM]) to assess trends in the relative abundance, distribution, and size composition of green turtles in Texas inshore waters during 1991–2010. Overall catch per unit effort (CPUE) in the LLM (1.5 turtles/km-hr) was significantly higher than that observed in the other 2 estuaries and corresponded to general climate patterns and seagrass areal coverage along the Texas coast. Yearly CPUE of green turtles from the LLM exhibited a significant exponential increase from 1991 to 2010, despite variability in capture rate during recent years. Mean straight carapace length (SCL) of green turtles was statistically similar across the 3 study areas and indicative o...

Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr) and SSMs (53.3 to 68.3 cm straightline carapace length (SCL)) estimated using the "rapprochement" skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp's ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends.

The Kemp's ridley sea turtle Lepidochelys kempii is recovering from declines that reduced nesting from a single-day estimate of 10 000 to 40 000 females in 1947 to

Three trials comprised of 4, 16, and 8 captive-reared juvenile loggerhead sea turtles ( Caretta caretta ) were run for 164, 134, and 213 d, respectively, to evaluate platform terminal transmitter (PTT) attachment methods. Power-Fast® epoxy-only (PF-only) and Power-Fast®/Sonic-Weld® epoxy putty (PF/SW) protocols were tested in each trial, and the latter trials also included experimental, less-rigid methods incorporating 1.5 and 3.0 mm neoprene. Protocols were modified slightly for the latter trials compared to those of the first, utilizing coarser sandpaper for site preparation and discarding initial “squeezes” of epoxy. Despite a low average growth rate (0.012 cm/d), three of four PTTs were shed from the loggerheads in Trial 1. All PTTs remained attached in Trial 2 after an average straight carapace length (SCL) increase of 3.4 cm (0.024 cm/d), suggesting that protocol modifications improved upon Trial 1 methods. One 3.0-mm neoprene attachment and a PF-only attachment were shed during Trial 3 after SCL increases of 3.7 and 5.4 cm, respectively. The other six PTTs remained attached after an average SCL increase of 9.6 cm (0.045 cm/d), but significant gaps occurred along the perimeters of the three remaining non-neoprene attachments. Two neoprene attachments became loose along the edges while their centers remained secure, suggesting that carefully-applied neoprene attachments may be beneficial for tracking smaller, faster-growing sea turtles.

The threat that exposure to organohalogen (OH) contaminants poses to endangered populations of Kemp’s ridley ( Lepidochelys kempii ) and green sea turtles ( Chelonia mydas ) is not well understood, partly because few OH data are available. Blood samples from live juvenile and sub-adult L. kempii ( n = 46) and C. mydas ( n = 9) from the Gulf of Mexico and from L. kempii from the southeastern US coast ( n = 3) were extracted using microwave-assisted extraction, and analyzed by large volume injection gas chromatography–mass spectrometry for 85 polychlorinated biphenyls (PCBs), 25 organochlorine pesticides (OCPs) and 27 polybrominated diphenyl ethers (PBDEs). Plasma chemistries, hematology and immune responses were also assessed. Concentrations of ΣPCBs (geometric mean, range: 3190 pg g −1 , 227–21 590 pg g −1 blood), ΣDDTs (geometric mean, range: 541 pg g −1 , 161–4310 pg g −1 blood) and OCPs in L. kempii from the Gulf were comparable to those reported in L. kempii from the Atlantic. ΣPBDEs were detected in all samples (geometric mean, range: 146 pg g −1 , 19.5–1450 pg g −1 blood), with PBDE 47, 99, 100, 153 and 154 being the predominant congeners. ΣPCBs, ΣDDTs and Σchlordanes were one order of magnitude lower in green turtles, and ΣPBDE concentrations were lower by half due to trophic level differences. L. kempii from the southeast USA had higher percentages of highly chlorinated PCBs indicating exposure to Aroclor 1268. Blood urea nitrogen was positively correlated to Σchlordanes, and ΣPCBs were inversely correlated to creatine phosphokinase in L. kempii . These data help establish baseline contaminant concentrations in live L. kempii and C. mydas .

Increased nesting by the critically endangered Kemp's ridley sea turtle Lepidochelys kempii at Rancho Nuevo, Mexico has been complemented by commencement and growth of nesting in Texas, USA. Six female Kemp's ridleys were fitted with satellite transmitters after nesting on the upper Texas coast during 2005 and 2006 and subsequently tracked for 20 to 153 d. Two were con- firmed nesting a second time on Galveston Island, whereas satellite tracks of these and 2 other females suggested that each nested a total of 3 times on the upper Texas coast within a season. Five of the females showed fidelity to nearshore waters off Galveston Island during their respective nest- ing seasons, and all 4 ridleys tracked after the nesting season established foraging areas on the con- tinental shelf of Louisiana. One female stranded dead on Galveston Island 20 d after transmitter deployment. Fidelity of these nesters to the upper Texas coast, along with apparent increases in nest- ing activity in the region, warrant establishment of sea turtle management schemes comparable to those utilized in south Texas. Potential threats posed by urbanization, tourism, and in-water activities along the upper Texas coast should be addressed by federal, state, and local authorities, whereas increased nesting may also present opportunities for educational outreach and responsible eco- tourism.

The Kemp's Ridley (Lepidochelys kempii) is one of the most endangered sea turtles in the world, and it possesses temperature-dependent sex determination (TSD). Sex ratios produced under TSD can vary widely and can affect the reproductive ecology of a population. Therefore, sex ratios produced from TSD are of ecological and conservation interest. The current study validated and utilized a testosterone radioimmunoassay (RIA) to examine the sex ratio of juvenile Kemp's Ridleys inhabiting the waters near Steinhatchee, Florida. Testosterone levels were measured in blood samples collected from juvenile Kemp's Ridleys captured over a three-year period. Results of this study indicate that a significant female bias (approximately 3.7:1) occurs in the aggregation of juvenile Kemp's Ridleys inhabiting the waters near Steinhatchee.

Blood samples were collected from 58 wild Kemp's ridley sea turtles (Lepidochelys kempii) to examine the physiological effects of capture in entanglement nets. Captured turtles were placed in holding tanks or in-water cages to examine whether the postcapture holding protocol influenced the time course of recovery of blood homeostasis. Lactate concentrations at capture were 4.5 ± 0.3 and 3.5 ± 0.3 mmol/L (mean ± SE) for L. kempii assigned to the in-water-cage and holding-tank treatments, respectively. Turtles held in holding tanks for 1 h exhibited a significant increase in lactate concentration over capture levels, whereas lactate concentrations in the cage-held animals did not change. Lactate concentrations declined to less than 1.0 mmol/L by 6 and 10 h post capture for turtles in the in-water-cage and holding-tank treatments, respectively. Plasma norepinephrine (NE) and epinephrine (E) concentrations at capture were substantially elevated above base-line levels reported in the literature for comparably ...

Swimming performance of Kemp's ridley sea turtles Lepidochelys kempi (Garman) was evaluated over a 6-month period to determine whether an exercise regine increased swimming capacity in captive reared turtles. Three experimental treatments included: (1) turtles exercised twice weekly and exposed to a weekly stamina test; (2) turtles subjected only to a weekly stamina test; and (3) non-exercised controls exposed to a single stamina test at the end of the study. No statistically significant difference in swimming capacity was detected between treatments 1 and 2, although treatment 1 turtles achieved higher performance levels than those from treatment 2. However, treatment 1 turtles exhibited fewer breaths/min (BRM) and foreflipper strokes/min (FSM) during stamina tests than did treatment 2 turtles. In contrast, control turtles (treatment 3) were unable to achieve the minimum swimming performance level. These results indicate that the swimming performances of exercised turtles significantly improved during captive rearing. The possible effects of an exercise regime on post-release survival potential are discussed.

Laparoscopies were performed on 225 hawksbill turtles (Eretmochelys imbricata) following nesting emergences on Milman Island, northern Great Barrier Reef, Australia during the 1992–1995 summer seasons. New recruits (first time breeders) made up between 9.8% and 14.3% of the nesting population across 4 summer seasons. Remigrants were not significantly larger or heavier than recruits, indicating that females nesting for the first time do not necessarily recruit to a nesting population at the smallest sizes. Further investigations are required to determine if the summer recruitment rate is reflective of the entire nesting population, which nests year-round.

Tag recoveries from four adult female hawksbill turtles, Eretmochelys imbricata, tagged on the Great Barrier Reef, Australia, are reported. Hawksbill turtles on breeding migrations move between Australia and neighbouring countries including Vanuatu, Solomon Islands, Papua New Guinea and Indonesia. Migratory distances between foraging areas and nesting beaches ranged from 368 to 2425 km. A review of data from tag recoveries, genetic analysis and satellite telemetry indicates that adult female hawksbill turtles often exhibit migratory behaviour parallelling that of other marine turtle species. This study refutes the myth that hawksbill turtles remain resident at reefs associated with their nesting beaches.

Immunoblots of interphotoreceptor matrix preparations from 20 species belonging to six vertebrate classes were probed with antibodies against bovine interstitial retinol-binding protein (b-IRBP). Each preparation displayed an immunoreactive protein band. In the Osteichthyes, the apparent Mr of this band was 67,600 +/- 2,700 (mean +/- SD, n = 8). In two of the Osteichthyes, the band was resolved into a closely spaced doublet. Including previously published data for five mammals and one amphibian, species from the other classes (Chondrichthyes, one species; Amphibia, four species; Reptilia, one species; Aves, one species; Mammalia, nine species) had IRBPs with Mr that averaged 2.0 times that of the Osteichthyes, namely 134,200 +/- 8,600 (mean +/- SD, n = 17). Frog IRBP was very similar to mammalian IRBP in terms of its immunohistochemical distribution (determined with rabbit anti-frog IRBP antibodies), its molecular weight (sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel-filtration chromatography), retinol- and concanavalin A-binding ability, and because it was synthesized and secreted in vitro by the isolated retina but not by the pigmented layers of eye. Goldfish IRBP apparently binds exogenous (3H)-retinol but does not bind concanavalin A and has about half the Mr of frog IRBP. The occurrence of IRBP-like proteins cross-reacting with anti b-IRBP antibodies in the interphotoreceptor matrix of all six major vertebrate classes is consistent with the hypothesis that IRBP is an important element in the vertebrate visual cycle.

A survey of sportfishing activity at the P. H. Robinson Generating Station discharge into Galveston Bay, Texas was taken from 21 October 1968 through 8 November 1969. During 108 daily checks, 1,063 fishermen were interviewed and 2,635 fish counted. Fishing activity was related to season and temperature of the heated effluent. Maximum fishing pressure and largest catches occurred during the period December 1968 through April 1969 and November 1969 when discharge water temperatures and flow rates were minimum. Lowest angling activity and catch rates were recorded from June through September 1969 when water temperatures approached 40 C in the upper part of the fishing area. Atlantic croaker, Micropogon undulatus; sea catfish (hardhead), Arius felis; sand seatrout, Cynoscion arenarius; black drum, Pogonias cromis; red drum, Sciaenops ocellata; and spot, Leiostomus xanthurus, in order of decreasing abundance, accounted for 96.7% of the fish counted during the study. Seine, trawl, and trammel net data ...