Lifetime glucocorticoid profiles in baleen of right whale calves: Potential relationships to chronic stress of repeated wounding by Kelp Gulls

Baleen tissue accumulates stress hormones (glucocorticoids, GC) as it grows, along with other adrenal, gonadal and thyroid hormones. The hormones are deposited in a linear fashion such that a single plate of baleen allows retrospective assessment and evaluation of long-term trends in the whales´ physiological condition. In whale calves, a single piece of baleen contains hormones deposited across the lifespan of the animal, with the tip of the baleen representing prenatally grown baleen. This suggests that baleen recovered from stranded carcasses of whale calves could be used to examine lifetime patterns of stress physiology. Here we report lifetime profiles of cortisol and corticosterone in baleen of a North Atlantic right whale ("NARW" - Eubalaena glacialis) calf that died from a vessel strike, as well as four southern right whale ("SRW" - Eubalaena australis) calves that were found dead with varying severity of chronic wounding from Kelp Gull (Larus dominicanus) attacks. In all five calves, prenatally grown baleen exhibited a distinctive profile of elevated glucocorticoids that declined shortly before birth, similar to GC profiles reported from baleen of pregnant females. After birth, GC profiles in calf baleen corresponded with the degree of wounding. The NARW calf and two SRW calves with no or few gull wounds had relatively low and constant GC content throughout life, while two SRW calves with high numbers of gull wounds had pronounced elevations in baleen GC content in postnatal baleen followed by a precipitous decline shortly before death, a profile suggestive of prolonged chronic stress. Baleen samples may present a promising and valuable tool for defining the baseline physiology of whale calves and may prove useful for addressing conservation-relevant questions such as distinguishing acute from chronic stress and, potentially, determining cause of death.Fil: Ajó, Alejandro A. Fernández. Northern Arizona University; Estados UnidosFil: Hunt, Kathleen E.. Northern Arizona University; Estados UnidosFil: Uhart, Marcela María. University of California at Davis; Estados UnidosFil: Rowntree, Victoria. University of Utah; Estados UnidosFil: Sironi, Mariano. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Instituto de Conservación de Ballenas; ArgentinaFil: Marón, Carina Flavia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Instituto de Conservación de Ballenas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Martino, Matias. Southern Right Whale Health Monitoring Program; ArgentinaFil: Buck, Charles Loren. Northern Arizona University; Estados Unido

Fatty acids and stable isotopes (13C, 15N) in southern right whale Eubalaena australis calves in relation toage and mortality at Peninsula Valdes, Argentina

Baleen whales accumulate fat reserves during the summer to sustain reproduction while fasting in the winter. The southern right whale Eubalaena australis population that calves off Península Valdés, Argentina, experienced high calf mortality events from 2003 to 2013 and poor nutritional states of mothers could be a contributing cause. Previous studies found that the population’s reproductive success is influenced by prey availability. Mothers unable to build sufficient fat reserves or feeding on prey with different nutritional value may fail to meet the demands of lactation. Milk is the only source of nutrients and energy for calves at Valdés, so their fatty acids (FAs) and stable isotopes should reflect their mother’s diet and feeding-ground locations. Here, we compared FA profiles and C and N stable isotopes of dead calves with those of living calves to evaluate the potential impact of maternal nutrition on calf survival. We found no differences in the FA composition of blubber in dead and living calves, indicating similar maternal diets. Likewise, the isotopic values of living and dead calves imply that their mothers had similar foraging ranges. However, FA composition was greatly affected by calf length, indicating effects of calf age and duration of nursing. These findings suggest that mothers of dead calves did not feed on different diets or feeding grounds compared to mothers of living calves. Future research should further assess the overall health and body condition of the Valdés southern right whale calves.Fil: Marón, Carina Flavia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Conservación de Ballenas; ArgentinaFil: Budge, Suzanne M.. Dalhousie University Halifax; CanadáFil: Ward, Robert E.. Utah State University; Estados UnidosFil: Valenzuela, Luciano Oscar. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Departamento de Arqueología. Laboratorio de Ecología Evolutiva Humana (Sede Quequén); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: Di Martino, Matías. Programa de Monitoreo Sanitario Ballena Franca Austral; ArgentinaFil: Ricciardi, Marcos. Instituto de Conservación de Ballenas; ArgentinaFil: Sironi, Mariano. Instituto de Conservación de Ballenas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecológica; Argentina. Programa de Monitoreo Sanitario Ballena Franca Austral; ArgentinaFil: Uhart, Marcela. Programa de Monitoreo Sanitario Ballena Franca Austral; Argentina. University of California; Estados UnidosFil: Seger, Jon. University Of Utah. Department Of Biology; Estados UnidosFil: Rowntree, Victoria J.. University Of Utah. Department Of Biology; Estados Unidos. Instituto de Conservación de Ballenas; Argentina. Programa de Monitoreo Sanitario Ballena Franca Austral; Argentina. Whale Conservation Institute/Ocean Alliance; Estados Unido

The recovery of North Atlantic right whales, Eubalaena glacialis, has been constrained by human-caused mortality

North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and since then they have been in decline. We assessed the extent to which the relatively slow increase demonstrated by NARW was intrinsic, and how much could be due to anthropogenic impacts. In order to do so, we first compared calf counts of three populations of Southern right whales (SRW), E. australis, with that of NARW, over the period 1992–2016. By this index, the annual rate of increase of NARW was approximately one-third of that of SRW. Next we constructed a population projection model for female NARW, using the highest annual survival estimates available from recent mark–resight analysis, and assuming a four-year calving interval. The model results indicated an intrinsic rate of increase of 4% per year, approximately twice that observed, and that adult female mortality is the main factor influencing this rate. Necropsy records demonstrate that anthropogenic mortality is the primary cause of known mortality of NARW. Anthropogenic mortality and morbidity has limited the recovery of NARW, and baseline conditions prior to their recent decline were already jeopardizing NARW recovery.The North Atlantic Right Whale Catalog is maintained with support from ongoing contracts from NOAA Fisheries. J.B. has been funded since at least 1993 by various Australian Government Environment Agencies, since 2015 the National Environment Marine Sciences Program, Marine Diversity Hub. K.F. thanks the Island Foundation for support during the collection of the South African aerial survey data between 2012 and 2015. Various institutions funded the South African aerial surveys over the data collection period, including Moby Dick Rum, Exclusive Trust, the Island Foundation, the National Research Foundation, members of the Offshore Petroleum Association of South Africa and the International Whaling Commission. The Brazilian Right Whale Catalog have been supported by several companies through funding to Projeto Baleia Franca, in particular PETROBRAS Brazilian Oil Company and Santos Brasil Company. V.R. thanks the many individuals and non-profit organizations who funded the 47 years of aerial surveys of the Argentine right whales, in particular Sarah Haney for her support in many of our lean years. V.R.’s research permits were issued annually by the Direccio´n de Fauna y Flora Silvestre and the Subsecretarı´a de Turismo y A ´ reas Protegidas of Chubut Province, Argentina.http://rsos.royalsocietypublishing.orgam2019Mammal Research InstituteZoology and Entomolog

Pacific Ocean–wide profile of CYP1A1 expression, stable carbon and nitrogen isotope ratios, and organic contaminant burden in sperm whale skin biopsies

This paper is not subject to U.S. copyright. The definitive version was published in Environmental Health Perspectives 119 (2011): 337-343, doi:10.1289/ehp.0901809.Background: Ocean pollution affects marine organisms and ecosystems as well as humans. The International Oceanographic Commission recommends ocean health monitoring programs to investigate the presence of marine contaminants and the health of threatened species and the use of multiple and early-warning biomarker approaches. Objective: We explored the hypothesis that biomarker and contaminant analyses in skin biopsies of the threatened sperm whale (Physeter macrocephalus) could reveal geographical trends in exposure on an oceanwide scale. Methods: We analyzed cytochrome P450 1A1 (CYP1A1) expression (by immunohistochemistry), stable nitrogen and carbon isotope ratios (as general indicators of trophic position and latitude, respectively), and contaminant burdens in skin biopsies to explore regional trends in the Pacific Ocean. Results: Biomarker analyses revealed significant regional differences within the Pacific Ocean. CYP1A1 expression was highest in whales from the Galapagos, a United Nations Educational, Scientific, and Cultural Organization World Heritage marine reserve, and was lowest in the sampling sites farthest away from continents. We examined the possible influence of the whales’ sex, diet, or range and other parameters on regional variation in CYP1A1 expression, but data were inconclusive. In general, CYP1A1 expression was not significantly correlated with contaminant burdens in blubber. However, small sample sizes precluded detailed chemical analyses, and power to detect significant associations was limited. Conclusions: Our large-scale monitoring study was successful at identifying regional differences in CYP1A1 expression, providing a baseline for this known biomarker of exposure to aryl hydrocarbon receptor agonists. However, we could not identify factors that explained this variation. Future oceanwide CYP1A1 expression profiles in cetacean skin biopsies are warranted and could reveal whether globally distributed chemicals occur at biochemically relevant concentrations on a global basis, which may provide a measure of ocean integrity.Funding was provided by National Institute of Environmental Health Sciences grant P42-ES-0469, Superfund Basic Research Program grant P42ES007381, NOAA Sea Grant NA86RG0075 R/B-162, and the Ocean Alliance

Stable isotopes (δ15N, δ13C, δ34S) in skin reveal diverse food sources used by Southern right whales Eubalaena australis

Skin samples collected from living Southern right whales (SRWs) off Península Valdés, Argentina, show a wide range of stable isotope values (δ15N, δ13C, δ34S). These were compared to the isotopic signatures of euphausiids and copepods from different areas across the Southwestern South Atlantic and the Atlantic sector of the Southern Ocean. Our results suggest that that this population of SRWs uses at least 3 distinct food sources. Each food source May represent a single feeding ground or a combination of feeding grounds with different prey species distributions. Individual whales pursue foraging strategies that vary substantially in the amounts of time they spend in different feeding grounds along their migratory paths. The 3 grounds that appear to contribute most to the diets of Península Valdés SRWs correspond to areas previously documented in the log books of whaling ships: the Patagonian Shelf, South Georgia and the waters of the Polar Front. It is possible that additional feeding areas are also currently being used in the South Atlantic. Age and sex classes differ isotopically, but these differences could be caused by biomechanical or physiological characteristics rather than by age- and sex-specific specialization in different feeding areas.Fil: Valenzuela, Luciano Oscar. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Departamento de Arqueología. Laboratorio de Ecología Evolutiva Humana (Sede Quequén); ArgentinaFil: Rowntree, Victoria. University Of Utah. Department Of Biology; Estados UnidosFil: Sironi, Mariano. Instituto de Conservación de Ballenas; ArgentinaFil: Seger, Jon. University Of Utah. Department Of Biology; Estados Unido

Global climate drives southern right whale (Eubalaena australis) population dynamics

Sea surface temperature (SST) time-series from the southwest Atlantic and the El Niño 4 region in the western Pacific were compared to an index of annual calving success of the southern right whale (Eubalaena australis) breeding in Argentina. There was a strong relationship between right whale calving output and SST anomalies at South Georgia in the autumn of the previous year and also with mean El Niño 4 SST anomalies delayed by 6 years. These results extend similar observations from other krill predators and show clear linkages between global climate signals and the biological processes affecting whale population dynamics