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1.
Young green turtles (Chelonia mydas) spend their early lives as oceanic omnivores with a prevalence of animal prey. Once they settle into neritic habitats (recruitment),
they are thought to shift rapidly to an herbivorous diet, as revealed by studies in the Greater Caribbean. However, the precise
timing of the ontogenic dietary shift and the actual relevance of animal prey in the diet of neritic green turtles are poorly
known elsewhere. Stable isotopes of carbon, sulfur and nitrogen in the carapace scutes of 19 green turtles from Mauritania
(NW Africa), ranging from 26 to 102 cm in curved carapace length (CCLmin), were analyzed to test the hypothesis of a rapid
dietary shift after recruitment. Although the length of residence time in neritic habitats increased with turtle length, as
revealed by a significant correlation between turtle length and the δ13C and the δ34S of the scutes, comparison of the δ15N of the innermost and outermost layers of carapace scutes demonstrated that consumption of macrophytes did not always start
immediately after recruitment, and turtles often resumed an animal-based diet after starting to graze on seagrasses. As a
consequence, seagrass consumption did not increase gradually with turtle size and animal prey largely contributed to the diet
of turtles within the range 29–59 cm CCLmin (76–99% of assimilated nutrients). Seagrass consumption by turtles larger than
59 cm CCLmin was higher, but they still relied largely on animal prey (53–76% of assimilated nutrients). Thus, throughout
most of their neritic juvenile life, green turtles from NW Africa would be better classified as omnivores rather than herbivores.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
MATTHEW E. WOLAK GEORGE W. GILCHRIST VICTORIA A. RUZICKA DANIEL M. NALLY RANDOLPH M. CHAMBERS 《Conservation biology》2010,24(5):1268-1277
Abstract: Juvenile growth rate and adult body size are important components of life‐history strategies because of their direct impact on fitness. The diamondback terrapin (Malaclemys terrapin) is a sexually dimorphic, long‐lived turtle inhabiting brackish waters throughout the Atlantic and Gulf coasts of the United States. In parts of its range, terrapins face anthropogenically imposed mortality: juveniles of both sexes inadvertently enter commercial crab traps and drown. For adult females, the carapace eventually grows large enough that they cannot enter traps, whereas males almost never reach that critical size. We compared age structure, carapace dimensions, growth curves, and indices of sexual dimorphism for a Chesapeake Bay population of terrapins (where mortality of turtles is high due to crab traps) with contemporary terrapins from Long Island Sound and museum specimens from Chesapeake Bay (neither group subject to commercial crab traps). We also calculated the allochronic and synchronic rates of evolutionary change (haldanes) for males and females to measure the rate of trait change in a population or between populations, respectively. We found a dramatic shift to a younger male age structure, a decrease in the length of time to terminal female carapace size, a 15% increase in female carapace width, and an increase in sexual dimorphism in Chesapeake Bay. In a new twist, our results implicate a fishery in the selective increase in size of a reptilian bycatch species. These sex‐specific changes in life history and demography have implications for population viability that need to be considered when addressing conservation of this threatened turtle. 相似文献
3.
Leatherback turtles, Dermochelys coriacea, are highly migratory, spending most of their lives submerged or offshore where their feeding habits are difficult to observe.
In order to elucidate the foraging ecology of leatherbacks off Massachusetts, USA, stable isotope analyses were performed
on leatherback tissues and prey collected from 2005 to 2009. Stable isotope ratios of nitrogen and carbon were determined
in whole blood, red blood cells, blood plasma, muscle, liver, and skin from adult male, female, and subadult leatherbacks.
Isotopic values were analyzed by body size (curved carapace length) and grouped by sex, and groups were tested for dietary
differences. Gelatinous zooplankton samples were collected from leatherback foraging grounds using surface dip nets and stratified
net tows, and prey contribution to leatherback diet was estimated using a two-isotope Bayesian mixing model. Skin and whole
blood δ13C values and red blood cell δ15N values were correlated with body size, while δ13C values of red blood cells, whole blood, and blood plasma differed by sex. Mixing model results suggest that leatherbacks
foraging off Massachusetts primarily consume the scyphozoan jellyfishes, Cyanea capillata and Chrysaora quinquecirrha, and ctenophores, while a smaller proportion of their diet comes from holoplanktonic salps and sea butterflies (Cymbuliidae).
Our results are consistent with historical observations of leatherback turtles feeding on scyphozoan prey in this region and
offer new insight into size- and sex-related differences in leatherback diet. 相似文献
4.
Time-depth recorders were attached to immature hawksbills (Eretmochelys imbricata Linnaeus, 1766) residing at the northwestern cliffs of Mona Island, Puerto Rico. Data on diving profiles obtained from four turtles of 32.0 to 53.4 cm straight carapace length revealed strong similarities in behavioral patterns. During daylight hours, turtles were active an average 8.4 h per day, surfacing 3.6% of the time. Length of foraging dives correlated with turtle size, with mean durations ranging from 8.6 to 14.0 min. Foraging dives, with a mean depth of 4.7 m, were associated with feeding on encrusting sponges. At night, turtles were mostly inactive, surfacing 1.8% of the time and with individual mean submergence intervals of between 30.4 and 37.1 min. From the surfacing behavior of turtles making deep and long dives, it is inferred that dives were aerobic, with the turtles making use of oxygen stores in addition to that of the lung. 相似文献
5.
Dietary information obtained from stomach contents can provide a wealth of information on an animal’s ecology. Where animals
are cryptic, such as the post-hatchling life history stage of a sea turtle, the ecological insight that dietary analyses can
provide, may be otherwise unobtainable. Investigations into post-hatchling turtle stomach contents have found planktonic organisms,
dominated by pelagic molluscs and crustaceans, hydrozoans, Sargassum and fish eggs. The nature of these dietary organisms provides evidence for the widely accepted hypothesis that, with the
exception of the flatback turtle (Natator depressus), the post-hatchling stage of a sea turtle’s life history is pelagic and oceanic. As the majority of studies that have investigated
the stomach contents of post-hatchling sea turtles have been conducted on loggerhead turtles (Caretta caretta) in the northern Atlantic and Pacific Oceans, insight derived from dietary investigations into post-hatchling ecology is
biased. This study investigates the diet of post-hatchling green turtles (Chelonia mydas) and loggerhead turtles in the southwest Pacific Ocean. Stomach contents were obtained from 55 green and loggerhead post-hatchling
turtles that had stranded or been consumed by Coryphaena hippurus. Our findings demonstrate that loggerhead and green post-hatchlings in the southwest Pacific share similar feeding ecology
and feed on a variety of neustonic items that are indicative of an oceanic and pelagic existence. The dietary items consumed
by both species investigated belong to similar taxonomic groups as those found in previous studies with species level distinctions
occurring owing to the different geographical location. 相似文献
6.
草甘膦暴露可能对某些水生动物具有致死及亚致死毒性,但未见有涉及龟鳖类动物的行为毒理学的研究报道。用不同浓度草甘膦铵盐处理孵化中的乌龟卵来检测草甘膦暴露对其胚胎发育、孵出幼体大小、翻身能力以及空间学习能力的影响。结果表明,2~2 000 mg·L~(-1)浓度范围内的草甘膦铵盐暴露并不会影响乌龟卵孵化成功率、胚胎发育速率以及孵出个体的体质量和翻身时间,但对孵出幼体的空间学习能力产生一定影响。较高浓度的草甘膦铵盐暴露会导致孵出幼体的觅食时间延长、觅食过程中的运动距离增大。因此,胚胎期草甘膦铵盐暴露可能对乌龟孵出幼体的后续生长和存活有一定的负面效应。 相似文献
7.
C. JOSH DONLAN DANA K. WINGFIELD LARRY B. CROWDER CHRIS WILCOX 《Conservation biology》2010,24(6):1586-1595
Abstract: Little is known about how specific anthropogenic hazards affect the biology of organisms. Quantifying the effect of regional hazards is particularly challenging for species such as sea turtles because they are migratory, difficult to study, long lived, and face multiple anthropogenic threats. Expert elicitation, a technique used to synthesize opinions of experts while assessing uncertainty around those views, has been in use for several decades in the social science and risk assessment sectors. We conducted an internet‐based survey to quantify expert opinion on the relative magnitude of anthropogenic hazards to sea turtle populations at the regional level. Fisheries bycatch and coastal development were most often ranked as the top hazards to sea turtle species in a geographic region. Nest predation and direct take followed as the second and third greatest threats, respectively. Survey results suggest most experts believe sea turtles are threatened by multiple factors, including substantial at‐sea threats such as fisheries bycatch. Resources invested by the sea turtle community, however, appear biased toward terrestrial‐based impacts. Results from the survey are useful for conservation planning because they provide estimates of relative impacts of hazards on sea turtles and a measure of consensus on the magnitude of those impacts among researchers and practitioners. Our survey results also revealed patterns of expert bias, which we controlled for in our analysis. Respondents with no experience with respect to a sea turtle species tended to rank hazards affecting that sea turtle species higher than respondents with experience. A more‐striking pattern was with hazard‐based expertise: the more experience a respondent had with a specific hazard, the higher the respondent scored the impact of that hazard on sea turtle populations. Bias‐controlled expert opinion surveys focused on threatened species and their hazards can help guide and expedite species recovery plans. 相似文献
8.
The growing demand for fish around the world is an immediate threat to marine megafauna that are unintentionally captured in commercial and artisanal fishery operations. Bycatch mitigation strategies, such as turtle excluder devices, circle hooks, and net illumination, have successfully reduced this risk in some fisheries. We explored the effectiveness of gillnet illumination to reduce sea turtle captures in 2 artisanal fisheries (Mankoadze and Winneba, Ghana) under normal fishing conditions. We first quantified sea turtle bycatch in Ghana's artisanal gillnet fishery from 15 boats for 12 months. We then quantified catch of targeted species and sea turtle bycatch from 20 boats for 15 months (7427 net sets). For 10 of these boats, we placed a Centro Economy green light (1 LED) at each 10-m interval on the net. We also quantified target catch and sea turtle bycatch from 30 boats for 8 months (2250 net sets). In 15 of these boats, a Centro Deluxe green light (3 LEDs) was installed at 15-m intervals. Boats with economy lights and those with deluxe lights both exhibited an 81% decrease in sea turtle captures (W = 1, p < 0.001, n = 20; W = 215, p < 0.001, n = 30, respectively) compared with control boats without lights. Illuminated nets resulted in fewer turtle catches for leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), and green sea turtles (Chelonia mydas) (p < 0.05 for all species). Target catch (mass) (W = 53, p = 0.853 n = 20; W = 76, p = 0.449, n = 23) and value (W = 50, p = 1, n = 20; W = 69, p = 0.728, = 23) were not different across treatments. Our study affirms net illumination can reduce capture rates of 3 species of sea turtles, including the imperiled leatherback. Gear modification methods can successfully reduce bycatch if they are affordable and have broad applications for multiple species in different fisheries. 相似文献
9.
Skeletochronological analysis of Kemp’s ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtle humeri and scleral ossicles was conducted to (1) describe the characteristics of scleral ossicles in these species,
(2) determine whether the scleral ossicles contain annually deposited skeletal growth marks and (3) evaluate the potential
for skeletochronological analysis of ossicles to obtain age data for size classes and species of sea turtles whose humeri
exhibit prohibitive amounts of growth mark resorption. Humeri, entire eyes, and/or individual scleral ossicles were collected
from stranded, dead sea turtles that were found along the coasts of Florida, North Carolina, Virginia, and Texas, USA. Samples
were taken from a total of 77 neritic, juvenile Kemp’s ridleys ranging from 21.1 to 56.8 cm straightline carapace length (SCL),
as well as two Kemp’s ridley hatchlings. For loggerheads, samples were obtained from 65 neritic juvenile and adult turtles
ranging from 44.7 to 103.6 cm SCL and ten hatchlings. Examination of the ossicles revealed the presence of marks similar in
appearance to those found in humeri. The number of marks in the ossicles and humeri of individual juvenile Kemp’s ridleys
for which both structures were collected (n = 55) was equivalent, strongly indicating that the marks are annual. However, in large juvenile and adult loggerhead turtles
(n = 65), some significant resorption of early growth marks was observed, suggesting that although ossicles might be useful
for skeletochronological analysis of small juveniles, they may not provide a reasonable alternative to humeri for obtaining
age estimates for older loggerhead sea turtles. 相似文献
10.
Françoise Henry Céline Mahfouz Alice Delegrange Lucie Courcot 《Chemistry and Ecology》2017,33(4):271-280
Mercury (Hg) in fish can present a potential risk to wildlife and human consumers. Mercury levels were determined in 12 fish species and 2 invertebrate species from the French coast of the Eastern English Channel collected in June and November 2012. Total mercury concentrations in the muscle tissues ranged between 0.04 and 1.63 µg g-1 (d.w.). Dab and sandeel displayed a significant positive correlation between Hg concentrations and fish length. Seasonal differences in Hg concentrations were observed for dab and shrimp. The lesser weever showed significantly higher concentrations of Hg (0.97 ± 0.34 µg g-1 d. w.) than all other species. Gobies and sprat, which had the smallest size, showed significantly lower concentrations than herring, whiting, pout and sardine. Among the considered species, flatfish such as dab, flounder, plaice and sole displayed intermediate levels of Hg. In the present study, the fish age expressed as specimen length seems to be one of the major factors governing Hg contents in muscle tissues. Finally, mercury concentrations in commercial fish from the Eastern English Channel were below the levels fixed by the European Union for total mercury in edible parts of fish products. 相似文献
11.
The effect of the tumour-forming disease, fibropapillomatosis, on the somatic growth dynamics of green turtles resident in
the Pala’au foraging grounds (Moloka’i, Hawai’i) was evaluated using a Bayesian generalised additive mixed modelling approach.
This regression model enabled us to account for fixed effects (fibropapilloma tumour severity), nonlinear covariate functional
form (carapace size, sampling year) as well as random effects due to individual heterogeneity and correlation between repeated
growth measurements on some turtles. Somatic growth rates were found to be nonlinear functions of carapace size and sampling
year but were not a function of low-to-moderate tumour severity. On the other hand, growth rates were significantly lower
for turtles with advanced fibropapillomatosis, which suggests a limited or threshold-specific disease effect. However, tumour
severity was an increasing function of carapace size—larger turtles tended to have higher tumour severity scores, presumably
due to longer exposure of larger (older) turtles to the factors that cause the disease. Hence turtles with advanced fibropapillomatosis
tended to be the larger turtles, which confounds size and tumour severity in this study. But somatic growth rates for the
Pala’au population have also declined since the mid-1980s (sampling year effect) while disease prevalence and severity increased
from the mid-1980s before levelling off by the mid-1990s. It is unlikely that this decline was related to the increasing tumour
severity because growth rates have also declined over the last 10–20 years for other green turtle populations resident in
Hawaiian waters that have low or no disease prevalence. The declining somatic growth rate trends evident in the Hawaiian stock
are more likely a density-dependent effect caused by a dramatic increase in abundance by this once-seriously-depleted stock
since the mid-1980s. So despite increasing fibropapillomatosis risk over the last 20 years, only a limited effect on somatic
growth dynamics was apparent and the Hawaiian green turtle stock continues to increase in abundance. 相似文献
12.
The nesting season of the green turtle, Chelonia mydas on Wan-An Island, Peng-Hu Archipelago, Taiwan extended from early June to early October in both 1992 and 1993. Turtles nested on 9 of the 11 beaches on the island. The average inter-nesting interval was 14.9 d. A close relationship between the first reemergence time and the tidal cycle was found in the present study. The mean straight carapace length of the adult female was 96.6 cm. Female turtles produced from one to nine egg clutches; the average clutch size was 113 eggs. The mean egg size was 46.9 mm in diameter and 22.7 g in weight. The average incubation period was 49.3 d. The sediment characteristics of the beaches on the island are well within the incubation requirements for green turtle nesting. The average hatching success was 70%, but was lower in the artificial nest. The average size for hatchlings was 46.9 mm in straight carapace length and 22.7 g in body weight. The health of the hatchling is influenced by the adult female size, the nesting depth and the precipitation during incubation. 相似文献
13.
F. Bentivegna F. Valentino P. Falco E. Zambianchi S. Hochscheid 《Marine Biology》2007,151(5):1605-1614
Previous studies have shown that loggerhead sea turtles (Caretta caretta), monitored by satellite telemetry, complete long-distance migration between the western and eastern Mediterranean basins
following a seasonal pattern. This study investigated if these migration routes may be influenced by surface currents by superimposing
the tracks of three loggerhead turtles (curved carapace length >55 cm), migrating from the western to the eastern Mediterranean
basin, on Lagrangian data of current developed into pseudo-eulerian speed fields. The average travel speed of the turtles
was 1.6 km h−1 and did not depend on the current speed or direction. We observed a connection between surface currents and the turtles’
migration routes, although not a conclusive one. These observations show that neritic stage loggerhead turtles conduct migration
in two distinct alternate phases: the first characterized by high and constant speed of travel both when swimming with or
against currents and the second typified by low travel speeds and a good concurrence between the trailed routes and the course
of the currents. These two phases corresponded to two types of movements, one where the turtle migrates actively to reach
a specific destination (either neritic foraging, wintering or nesting ground) and the other, where the turtle drifts with
the mesoscale current and forages pelagically. It seemed thus, that the influence of currents on a turtle’s movements depends
on the turtle’s momentary behaviour and location of residence. 相似文献
14.
Before populations of green turtles (Chelonia mydas) were severely reduced by human overexploitation, the seagrass Thalassia testudinum was intensively grazed by green turtles in the Caribbean. To explore how nutrient composition of T. testudinum pastures responds to intense grazing pressure, we simulated green turtle grazing in 15 plots (each 3 m × 3 m) for 16 months
in the central Bahamas. Comparisons of clipped plots with 15 adjacent control (unclipped) plots revealed that simulated grazing
resulted in significantly higher energy, nitrogen, phosphorus, lignin, cutin, and condensed tannin content in blades in clipped
plots, but sediment organic content was not affected. By continually re-cropping blades in grazing plots, turtles ingest young,
actively growing blade tissue with higher energy, nitrogen, and phosphorus concentrations. Our 16-month clipping trial did
not generate the expected decline in nutrient content in T. testudinum blades under intensive grazing. However, significant decreases in nitrogen and organic matter reserves in rhizomes, with
declines apparent after 16 and 11 months, respectively, indicate that nutrient content of blades and/or blade productivity
may decline under continued clipping. 相似文献
15.
The species composition, catch and mortality rates of sea turtles captured incidentally by the tiger prawn fishery on Australia's northern coast in 1989 and 1990 were estimated by monitoring the fishery's catch. In 1990, the delayed rate of mortality from damage was estimated and the size composition was measured. Five species of turtles were captured: the flatback (Natator depressa, 59% of the total), loggerhead (Caretta caretta, 10%), olive ridley (Lepidochelys olivacea, 12%), green turtle (Chelonia mydas, 8%) and hawksbill (Eretmochelys imbricata, 5%). The turtle catches varied with water depth: the highest catch rates (0.068±0.006 turtles per trawl) were from trawls in water between 20 and 30 m deep, relatively few turtles (10%) were captured in water deeper than 40 m (25% of trawls). Catch rates varied with time of year: the highest catch rates were 0.098 (±0.013) turtles per trawl in winter. There was no significant difference in the overall catch rate (2= 0.047; p=0.8111; df=1) but a significant difference in mortality rate (2= 3.99; p<0.05; df=1) between the two years. The incidence of capture in the commercial fishery was 0.051 (±0.003) turtles per trawl towed for about 180 min, with 0.007 (±0.001) turtles per trawl drowning in the nets. There were no significant differences in the catch and mortality rates between the two years for any of the turtle species except the loggerhead, which had a significantly (2 = 11.029; p=0.0013; df=1) lower catch rate in 1990 (0.002±0.001 turtles per trawl) than in 1989 (0.008±0.002 turtles per trawl), and a significantly higher mortality in 1990 (33%) than in 1989 (19%). Catch rates and mortality varied between the species: the flatback had the highest catch rate (0.030±0.002 turtles per trawl) but the lowest mortality (10.9%); the loggerhead had a catch rate of 0.005±0.001 turtles per trawl, and high mortality (21.9%); the olive ridley had a catch rate of 0.006±0.001 turtles per trawl and a low mortality (12.5%); the green turtle's catch rate was 0.004±0.001 per trawl and mortality 12.0%; the hawksbill had the lowest catch rate (0.002±0.001 turtles per trawl) but highest mortality (26.4%). Based on the fishing effort (27 049 d for 1989 and 25 746 d for 1990), we estimate that 5 503 (±424) turtles were caught and returned to the sea in 1989 and 5 238 (±404) in 1990, of which 567±140 drowned in 1989 and 943±187 in 1990. In 1990, an estimated 25% of all captured turtles suffered some non-lethal damage; an estimated 21% of turltes were captured comatose and 4% were injured. We conclude that, considering other threats, trawl-induced drowning is not the major impact on turtle populations in northern Australia, but that measures to reduce drowning and delayed mortality would be desirable. 相似文献
16.
During 1955–2003, flipper tags were attached to 46,983 green turtles and ten turtles were fitted with satellite transmitters at Tortuguero, Costa Rica. Eight satellite-tracked turtles stayed within 135 km of the beach and probably returned to nest after release. The internesting area is more extensive than previously documented. Post-nesting migration routes of satellite-tracked turtles varied. Seven turtles swam close to the coast and three turtles swam through oceanic waters before moving toward nearshore areas. Sea surface height anomaly maps indicate that oceanic movements were consistent with the southwestern Caribbean gyre. Circling and semi-circling turtles could have been disoriented but submergence and surface times suggest they may have been feeding in Sargassum sp. concentrations. Rapid post-nesting migrations (mean 2.2 km hr−1) ended on benthic feeding grounds in shallow waters (<20 m) off Belize (n=1), Honduras (n=1) and Nicaragua (n=8). The spatial distribution of migration end points (n=10) and tag returns (n=4,669) are similar. Fishermen in Nicaragua target green turtles along migratory corridors and on foraging grounds. Management efforts are urgently needed in Nicaragua, particularly in the high-density feeding areas south and east of the Witties (N14°09 W82°45). The proximity of foraging grounds to the nesting beach (mean 512 km) may permit female turtles to invest more energy in reproduction and hence the Tortuguero population may have greater potential for recovery than other green turtle nesting populations. Recovery of the Tortuguero green turtle population will benefit countries and marine ecosystems throughout the Caribbean, especially Nicaragua. 相似文献
17.
We present data spanning approximately 100 years regarding the spatial and temporal occurrence of marine turtle sightings
and strandings in the northeast Atlantic from two public recording schemes and demonstrate potential signals of changing population
status. Records of loggerhead (n = 317) and Kemp’s ridley (n = 44) turtles occurring on the European continental shelf were most prevalent during the autumn and winter, when waters were
coolest. In contrast, endothermic leatherback turtles (n = 1,668) were most common during the summer. Analysis of the spatial distribution of hard-shell marine turtle sightings and
strandings highlights a pattern of decreasing records with increasing latitude. The spatial distribution of sighting and stranding
records indicates that arrival in waters of the European continental shelf is most likely driven by North Atlantic current
systems. Future patterns of spatial-temporal distribution, gathered from the periphery of juvenile marine turtles habitat
range, may allow for a broader assessment of the future impacts of global climate change on species range and population size. 相似文献
18.
Katia Ballorain Stéphane Ciccione Jérôme Bourjea Henri Grizel Manfred Enstipp Jean-Yves Georges 《Marine Biology》2010,157(12):2581-2590
We investigated the habitat use in green turtles exploiting a 13-ha multispecific seagrass meadow at Mayotte Island, south-western
Indian Ocean. A phyto-ecological survey shows the occurrence of eight seagrass species, dominated by Halodule uninervis and Syringodium isoetifolium, distributed according to four distinct seagrass communities along the depth gradient. Direct underwater censuses show that
green turtles occurred all over the meadow. Yet when community relative surface area was taken into account green turtles
preferentially frequented the most seaward, biomass-richer S. isoetifolium-dominated community, suggesting that green turtles compensate for their intrinsically nutrient-poor herbivorous diet. Additionally,
smaller (<80 cm standard curved carapace length, SCCL) individuals also preferentially occurred in the most shoreward H. univervis-dominated community where no larger (>80 cm SCCL) individuals were sighted, suggesting habitat use is indicative of diet
selection and may reflect size-specific food requirements and physiology. 相似文献
19.
A.S. Al-Akel H.F. Alkahem Al-Balawi F. Al-Misned Z. Ahmad E.M. Suliman 《毒物与环境化学》2013,95(10):1865-1878
The influence of dietary copper (Cu) exposure on accumulation, growth, and hematological parameters was investigated in Cyprinus carpio after sub-chronic ingestion of 0, 250, 500, 750 or 1000?mg?kg?1 for 60 days. The profile of Cu accumulation among tissues in C. carpio was dependent on the exposure period and Cu concentration. Liver of C. carpio was the predominant storage tissue and the order of Cu accumulation in tissues was liver?>?intestine?> gill?>?kidney?>?muscle. Cu concentration at >125?mg?kg?1 reduced growth rate, and was inversely related to growth. The RNA?:?DNA ratios were not affected by exposure and there was no correlation between growth rate and RNA?:?DNA ratio in liver and muscle. There were no significant effects of exposure on blood parameters except for magnesium. Cu exposure time and dose increased the serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic-pyruvic transaminase (SGPT) activity levels. 相似文献
20.
This study is the first report of post-nesting migrations of loggerhead sea turtles (Caretta caretta) nesting in Sarasota County (Florida, USA), their most important rookery in the Gulf of Mexico (GOM). In total, 28 females
(curved carapace length CCL between 82.2 and 112.0 cm) were satellite-tracked between May 2005 and December 2007. Post-nesting
migrations were completed in 3–68 days (mean ± SD = 23 ± 16 days). Five different migration patterns were observed: six turtles
remained in the vicinity of their nesting site while the other individuals moved either to the south-western part of the Florida
Shelf (n = 9 turtles), the Northeast GOM (n = 2 turtles), the South GOM (Yucatán Shelf and Campeche Bay, Mexico, and Cuba; n = 5 turtles) or the Bahamas (n = 6 turtles). In average, turtles moved along rather straight routes over the continental shelf but showed more indirect
paths in oceanic waters. Path analyses coupled with remote sensing oceanographic data suggest that most of long-distance migrants
reached their intended foraging destinations but did not compensate for the deflecting action of ocean currents. While six
out of seven small individuals (CCL < 90 cm) remained on the Florida Shelf, larger individuals showed various migration strategies,
staying on the Florida Shelf or moving to long-distance foraging grounds. This study highlights the primary importance the
Western Florida Shelf in the management of the Florida Nesting Subpopulation, as well as the need of multi-national effort
to promote the conservation of the loggerhead turtle in the Western Atlantic.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献