In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested ...to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nesting in Florida and (ii) examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1) a seasonal continental shelf-constrained migratory pattern along the northeast U.S. coastline, (2) a non-breeding residency in southern foraging areas and (3) a residency in the waters adjacent to the breeding area. Isotopic variability in both δ(13)C and δ(15)N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well δ(13)C and δ(15)N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61%) of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Determining patterns of migratory connectivity for highly-mobile, wide-ranging species, such as sea turtles, is challenging. Here, we combined satellite telemetry and stable isotope analysis to ...estimate foraging locations for 749 individual loggerheads nesting along the east central Florida (USA) coast, the largest rookery for the Northwest Atlantic population. We aggregated individual results by year, identified seven foraging hotspots and tracked these summaries to describe the dynamics of inter-annual contributions of these geographic areas to this rookery over a nine-year period. Using reproductive information for a subset of turtles (n = 513), we estimated hatchling yields associated with each hotspots. We found considerable inter-annual variability in the relative contribution of foraging areas to the nesting adults. Also reproductive success differed among foraging hotspots; females using southern foraging areas laid nests that produced more offspring in all but one year of the study. These analyses identified two high priority areas for future research and conservation efforts: the continental shelf adjacent to east central Florida and the Great Bahama Bank, which support higher numbers of foraging females that provide higher rates of hatchling production. The implementation of the continuous-surface approach to determine geographic origins of unknown migrants is applicable to other migratory species.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To critically review the status of the green sea turtle (Chelonia mydas) using the best available scientific studies as there is a prevailing view that this species is globally endangered and its ...marine ecosystem functions compromised. Ogasawara (Japan), Hawaii (USA), Great Barrier Reef (Australia), Florida (USA), Tortuguero (Costa Rica). We compiled seasonal nesting activity data from all reliable continuous long-term studies (> 25 years), which comprised data series for six of the world's major green turtle rookeries. We estimated the underlying time-specific trend in these six rookery-specific nester or nest abundance series using a generalized smoothing spline regression approach. Estimated rates of nesting population increase ranged from c. 4-14% per annum over the past two to three decades. These rates varied considerably among the rookeries, reflecting the level of historical exploitation. Similar increases in nesting population were also evident for many other green turtle stocks that have been monitored for shorter durations than the long-term studies presented here. We show that six of the major green turtle nesting populations in the world have been increasing over the past two to three decades following protection from human hazards such as exploitation of eggs and turtles. This population recovery or rebound capacity is encouraging and suggests that the green turtle is not on the brink of global extinction even though some stocks have been seriously depleted and are still below historical abundance levels. This demonstrates that relatively simple conservation strategies can have a profound effect on the recovery of once-depleted green turtle stocks and presumably the restoration of their ecological function as major marine consumers.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The brain and adrenal are critical control centers that maintain body homeostasis under basal and stress conditions, and orchestrate the body's response to stress. It is noteworthy that patients with ...stress-related disorders exhibit increased vulnerability to mental illness, even years after the stress experience, which is able to generate long-term changes in the brain's architecture and function. High levels of glucocorticoids produced by the adrenal cortex of the stressed subject reduce neurogenesis, which contributes to the development of depression. In support of the brain-adrenal connection in stress, many (but not all) depressed patients have alterations in the components of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis, with enlarged adrenal cortex and increased glucocorticoid levels. Other psychiatric disorders, such as post-traumatic stress disorder, bipolar disorder and depression, are also associated with abnormalities in hippocampal volume and hippocampal function. In addition, hippocampal lesions impair the regulation of the LHPA axis in stress response. Our knowledge of the functional connection between stress, brain function and adrenal has been further expanded by two recent, independent papers that elucidate the effects of stress on brain and adrenal stem cells, showing similarities in the way that the progenitor populations of these organs behave under stress, and shedding more light into the potential cellular and molecular mechanisms involved in the adaptation of tissues to stress.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In highly mobile philopatric species, defining the scale of natal homing is fundamental to characterizing population dynamics and effectively managing distinct populations. Genetic tools have ...provided evidence of regional natal philopatry in marine turtles, but extensive sharing of maternally inherited mitochondrial control region (CR) haplotypes within regions (< 500 km) often impedes identification of population boundaries. Previous CR-based analyses of Florida (USA) green turtle Chelonia mydas nesting sites detected at least 2 populations, but the ubiquity of haplotype CM-A3.1 among southern rookeries decreased the power to detect differentiation. We reassessed population structure by sequencing the mitochondrial microsatellite (short tandem repeat, mtSTR) in 786 samples from 11 nesting sites spanning 700 km from Canaveral National Seashore through Dry Tortugas National Park. The mtSTR marker subdivided CM-A3.1 into 12 haplotypes that were structured among rookeries, demonstrating independent female recruitment into the Dry Tortugas and Marquesas Keys nesting populations. Combined haplotypes provided support for recognition of at least 4 management units in Florida: (1) central eastern Florida, (2) southeastern Florida, (3) Key West National Wildlife Refuge, and (4) Dry Tortugas National Park. Recapture data indicated female nesting dispersal between islands < 15 km apart, but haplotype frequencies demonstrated discrete natal homing to island groups separated by 70 km. These isolated insular rookeries may be more vulnerable to climate change-mediated nesting habitat instability than those along continental coasts and should be monitored more consistently to characterize population status. Broader application of the mtSTR markers holds great promise in improving resolution of stock structure and migratory connectivity for green turtles globally.
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The first offshore wind energy auction in Germany led to a striking result. The average award price was 0.44 ct/kWh and even more interesting, 3 out of 4 awarded projects had a strike price of 0.0 ...ct/kWh. That implies that those projects will only receive the actual wholesale market price for electricity as revenue. Although there has been a strong decline in costs of offshore wind projects, such a result is still surprising. We analyzed this result auction-theoretically and showed how the auction design and the market environment can explain part of the outcome. However, another aspect of the explanation is the high risk that the awarded bidders take regarding the future development of both the project costs and the wholesale market price.
The onset of spring, noted by the timing of wildlife migratory and breeding behaviors, has been occurring earlier over the past few decades. Here, we examine 15 years of loggerhead sea turtle, ...Caretta caretta, nesting patterns along a 40.5 km beach on Florida's Atlantic coast. This small section of beach is considered to be the most important nesting area for this threatened species in the western hemisphere. From 1989 to 2003, the annual number of nests fluctuated between 13 000 and 25 000 without a conspicuous trend; however, based on a regression analysis, the median nesting date became earlier by roughly 10 days. The Julian day of median nesting was significantly correlated with near‐shore, May sea surface temperatures that warmed an average of 0.8°C over this period. This marine example from warm temperate/subtropical waters represents another response of nature to recent climate trends.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Obesity has become an epidemic problem in western societies, contributing to metabolic diseases, hypertension, and cardiovascular disease. Overweight and obesity are frequently associated with ...increased plasma levels of aldosterone. Recent evidence suggests that human fat is a highly active endocrine tissue. Therefore, we tested the hypothesis that adipocyte secretory products directly stimulate adrenocortical aldosterone secretion. Secretory products from isolated human adipocytes strongly stimulated steroidogenesis in human adrenocortical cells (NCI-H295R) with a predominant effect on mineralocorticoid secretion. Aldosterone secretion increased 7-fold during 24 h of incubation. This stimulation was comparable to maximal stimulation of these cells with forskolin$(2 \times 10^{-5}\>M)$. On the molecular level, there was a 10-fold increase in the expression of steroid acute regulatory peptide mRNA. This effect was independent of adipose angiotensin II as revealed by the stimulatory effect of fat cell-conditioned medium even in the presence of the angiotensin type 1 receptor antagonist, valsartan. None of the recently defined adipocytokines accounted for the effect. Mineralocorticoid-stimulating activity was heat sensitive and could be blunted by heating fat cell-conditioned medium to 99° C. Centrifugal filtration based on molecular mass revealed at least two releasing factors: a heat sensitive fraction (molecular mass >50 kDa) representing 60% of total activity, and an inactive fraction (molecular mass <50 kDa). However, the recovery rate increased to 92% when combining these two fractions, indicating the interaction of at least two factors. In conclusion, human adipocytes secrete potent mineralocorticoid-releasing factors, suggesting a direct link between obesity and hypertension.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Migratory animals spend different periods of their lives in widely separated and ecologically different locations; their experiences from one activity/period/site (e.g., foraging) can dramatically ...affect their success during another (e.g., breeding). Carry-over effects reflect the influence of foraging quality on reproductive behaviors of migratory species, such as nesting loggerhead sea turtle (Caretta caretta), which vary greatly in body size and reproductive parameters. We investigated carry-over effects on 330 loggerheads nesting at the Archie Carr National Wildlife Refuge (Melbourne Beach, Florida), one of the largest aggregations in the Western Hemisphere, using telemetry, stable isotope analysis and reproductive parameters. We assigned foraging locations used during the non-breeding period with discriminant function analysis and determined the relative contributions to different foraging regions from 2007 to 2012. Foraging regions significantly influenced female body size and fecundity. Loggerheads foraging southeast of the nesting beach in the vicinity of the Bahamas and Florida Keys laid larger clutches and had a shorter breeding frequency. On average, 47 % (±3 % SE) of the females foraged year-round in this area, while 33 % (±4 % SE) resided on the Southwest Florida continental shelf south of Tampa Bay and 18 % (±2 % SE) undertook seasonal migrations and foraged north of Cape Hatteras, North Carolina. Relative contributions to the foraging areas did not change over the 6-year period. The northern foraging area consistently contributed the fewest females despite being the most productive oceanographic region suggesting a trade-off between foraging area productivity and distance to the nesting beach. We reaffirm that the isotopic approach can be used to interpret trends in abundance at nesting beaches and demographic parameters affecting those trends. Understanding geospatial linkages and relative importance of foraging areas is critical to fostering appropriate management and conservation strategies for migratory species.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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