Joan Giménez

PCB pollution continues to impact populations of orcas and other dolphins in European waters

Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (nu2009=u2009929) or biopsied (nu2009=u2009152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB “hotspots” for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.

As main meal for sperm whales: Plastics debris

Marine debris has been found in marine animals since the early 20th century, but little is known about the impacts of the ingestion of debris in large marine mammals. In this study we describe a case of mortality of a sperm whale related to the ingestion of large amounts of marine debris in the Mediterranean Sea (4th published case worldwide to our knowledge), and discuss it within the context of the spatial distribution of the species and the presence of anthropogenic activities in the area that could be the source of the plastic debris found inside the sperm whale. The spatial distribution modelled for the species in the region shows that these animals can be seen in two distinct areas: near the waters of Almería, Granada and Murcia and in waters near the Strait of Gibraltar. The results shows how these animals feed in waters near an area completely flooded by the greenhouse industry, making them vulnerable to its waste products if adequate treatment of this industrys debris is not in place. Most types of these plastic materials have been found in the individual examined and cause of death was presumed to be gastric rupture following impaction with debris, which added to a previous problem of starvation. The problem of plastics arising from greenhouse agriculture should have a relevant section in the conservation plans and should be a recommendation from ACCOBAMS due to these plastics and sperm whales high mobility in the Mediterranean Sea.

Discrimination of stable isotopes in fin whale tissues and application to diet assessment in cetaceans

RATIONALEnIn stable isotope research, the use of accurate, species-specific diet-tissue discrimination factors (i.e., Δ(13)C and Δ(15)N) is central to the estimation of trophic position relative to primary consumers and to the identification of the dietary sources of an individual. Previous research suggested that the diet of fin whales from the waters off northwestern Spain is overwhelmingly based on krill, thus permitting reliable calculation of discrimination values in this wild population.nnnMETHODSnAfter confirming that the stable isotope ratios (δ(13)C and δ(15)N values) in muscle from 65 aged fin whales remained constant through age classes (4-65 years), the signatures were determined in muscle, bone protein, skin, liver, kidney, baleen plates and brain, as well as food (krill), from a subset of individuals to calculate discrimination factors. Signatures were determined by means of elemental analysis isotope ratio mass spectrometry (EA-IRMS) using a ThermoFinnigan Flash 1112.nnnRESULTSnThe isotopic values remained constant regardless of age. The mean Δ(15)N values between krill and whale tissues ranged from 2.04 in bone protein to 4.27‰ in brain, and those of Δ(13)C ranged from 1.28 in skin to 3.11‰ in bone protein. This variation was consistent with that found in other groups of mammals, and is attributed to variation in tissue composition and physiology.nnnCONCLUSIONSnBecause discrimination factors are relatively constant between taxonomically close species, the results here obtained may be reliably extrapolated to other cetaceans to improve dietary reconstructions. The skin discrimination factors are of particular relevance to monitoring diet through biopsies or other non-destructive sampling methods. The large difference in bone protein discrimination factors from those of other tissues should be taken into consideration when bone collagen is used to determine trophic level or to assess diet in paleodietary isotopic reconstructions.

Isotopic evidence of limited exchange between Mediterranean and eastern North Atlantic fin whales

RATIONALEnThe relationship between stocks of fin whales inhabiting the temperate eastern North Atlantic and the Mediterranean Sea is subject to controversy. The use of chemical markers facilitates an alternative insight into population structure and potential borders between stocks because the two areas present dissimilar isotopic baselines.nnnMETHODSnBaleen plates, composed of inert tissue that keeps a permanent chronological record of the isotopic value of body circulating fluids, were used to investigate connectivity and boundaries between the stocks. Values were determined by continuous flow isotope ratio mass spectrometry.nnnRESULTSnStable isotopes confirm that, while the two subpopulations generally forage in well-differentiated grounds, some individuals with characteristic Atlantic values do penetrate into the Mediterranean Sea up to the northernmost latitudes of the region. As a consequence, the border between the two putative subpopulations may be not as definite as previous acoustic investigations suggested. The discriminant function obtained in this study may assist researchers to use baleen plate isotopic data to assign the origin of fin whales of uncertain provenance.nnnCONCLUSIONSnThis study strengthens the stock subdivision currently accepted for management and conservation while recognizes a low level of exchange between the Mediterranean and temperate eastern North Atlantic subdivisions.

δ15N value does not reflect fasting in mysticetes.

The finding that tissue δ15N values increase with protein catabolism has led researchers to apply this value to gauge nutritive condition in vertebrates. However, its application to marine mammals has in most occasions failed. We investigated the relationship between δ15N values and the fattening/fasting cycle in a model species, the fin whale, a migratory capital breeder that experiences severe seasonal variation in body condition. We analyzed two tissues providing complementary insights: one with isotopic turnover (muscle) and one that keeps a permanent record of variations in isotopic values (baleen plates). In both tissues δ15N values increased with intensive feeding but decreased with fasting, thus contradicting the pattern previously anticipated. The apparent inconsistency during fasting is explained by the fact that a) individuals migrate between different isotopic isoscapes, b) starvation may not trigger significant negative nitrogen balance, and c) excretion drops and elimination of 15N-depleted urine is minimized. Conversely, when intensive feeding is resumed in the northern grounds, protein anabolism and excretion start again, triggering 15N enrichment. It can be concluded that in whales and other mammals that accrue massive depots of lipids as energetic reserves and which have limited access to drinking water, the δ15N value is not affected by fasting and therefore cannot be used as an indicatior of nutritive condition.

Identifying key habitat and seasonal patterns of a critically endangered population of killer whales

ruth esteban, philippe verborgh, pauline gauffier, joan gime’nez, isabel afa’n, ana can~adas, pedro garci’a, jose luis murcia, sara magalha~es, ezequiel andreu and renaud de stephanis CIRCE, Conservation Information and Research on Cetaceans, C/Cabeza de Manzaneda 3, Algeciras-Pelayo, 11390 Cadiz, Spain, GEMA, Grupo de Ecologia Marina Aplicada, Estacion Biologica de Donana, CSIC; C/Americo Vespucio, s/n, 41092, Isla de la Cartuja, Sevilla, Spain, LAST, Laboratorio de SIG y Teledeteccion, Estacion Biologica de Donana, CSIC; C/Americo Vespucio, s/n, 41092, Isla de la Cartuja, Sevilla, Spain, Alnilam Research and Conservation, Candamo 116, 28240 Hoyo de Manzanares, Madrid, Spain, ANSE Asociacion de Naturalistas del Sureste Plaza Pintor Jose Maria Parraga, 11, Bajo, 30002, Murcia, Spain, MAR ILIMITADO Porto da Baleeira de Sagres, 8650-368 Sagres, Portugal, TURMARES (Turismo Maritimo del Estrecho), Avd/Alcalde Juan Nunez 3, 11380 Tarifa, Cadiz, Spain

Bioaccumulation and biomagnification of classical flame retardants, related halogenated natural compounds and alternative flame retardants in three delphinids from Southern European waters

Occurrence and behaviour of classical (PBDEs) and alternative (HNs, HBB, PBEB, DBDPE and HBCD) flame retardants, together with naturally produced MeO-PBDEs, were studied in short-beaked common dolphin (Delphinus delphis), bottlenose dolphin (Tursiops truncatus) and long-finned pilot whale (Globicephala melas) in two sampling locations from Southern European waters. PBDEs, Dec 602, Dec 603, DP, α-HBCD and two MeO-PBDEs were detected in all three species. ∑PBDEs were between 17 and 2680 ng/g lw; ∑HNs were between 1.1 and 59 ng/g lw; α-HBCD levels ranged between 3.2 and 641 ng/g lw; ∑MeO-PBDEs were between 34 and 1966 ng/g lw. Bottlenose dolphins were the most contaminated species and some individuals could present health risk for endocrine disruption since levels found were above the reported threshold (1500 ng/g lw). Stable isotope analysis was used to evaluate the biomagnification capacity of these compounds. PBDEs, MeO-PBDEs and Dec 602 showed a significant positive correlation with trophic position.

Mobbing-like behavior by pilot whales towards killer whales: a response to resource competition or perceived predation risk?

Interspecific interactions can be based on positive or negative outcome. Within antagonist interactions, predation refers to a predator attacking and feeding on a prey while competition is an interaction where individuals compete for a common resource. Worldwide distributions of long-finned pilot whales and killer whales rarely overlap, and they are not known to feed on the same preys. However, in this study, we described the interactions between long-finned pilot whales and killer whales in the Strait of Gibraltar. The former was seen pursuing away the latter in all observations. The main hypotheses for the cause of these interactions are predation or competition. To test both hypotheses, movement patterns and isotopic niches of both species were investigated in the Strait of Gibraltar through satellite tagging and stable isotopes, respectively. Satellite tracks showed no overlap between one tagged pilot whale and one tagged killer whaler’s distributions during 21xa0days. Similarly, Euclidian distances between centroids of Bayesian standard ellipse areas of carbon and nitrogen stable isotopes were significantly different from zero, showing different isotopic niches for each species. This shows that no competition for the resources should exist between both species in the Strait of Gibraltar and that they do not feed on each other, suggesting that the interactions would not be related to predation. A possible historical presence of marine mammal-eating killer whales in the area, today disappeared, could explain the antipredator defense mobbing-like behavior of pilot whales observed in the Strait.

Maternal kinship and fisheries interaction influence killer whale social structure

The primary prey of killer whales (Orcinus orca) in the Strait of Gibraltar is the bluefin tuna (Thunnus thynnus). All killer whales observed in this area hunt tuna by chasing individual fish until they become exhausted and can be overcome. However, a subset of pods also interact with a dropline tuna fishery which has developed since 1995. Here, we investigated the social structure within and among social units (pods). Our data suggested that social structure was shaped by maternal kinship, which appears to be a species-specific trait, but also by foraging behavior, which is less common at the intra-population level. At the start of the study, only one cohesive pod interacted with the fishery, which during the course of the study underwent fission into two socially differentiated pods. Social structure within these two fishery-interacting pods was more compact and homogenous with stronger associations between individuals than in the rest of the population. Three other pods were never seen interacting with the fishery, despite one of these pods being regularly sighted in the area of the fishery during the summer. Sociality can influence the spread of the novel foraging behaviors and may drive population fragmentation, which, in this example, is already a critically small community. Observations of social changes in relation to changes in foraging at the earliest stages of diversification in foraging behavior and social segregation may provide insights into the processes that ultimately result in the formation of socially isolated discrete ecotypes in killer whales.

Biopsy wound healing in long-finned pilot whales (Globicephala melas)

CONSERVATION and management of natural systems often require biological research so that decisions can be based on scientific evidence ([Tracy and Brussard 1996][1]). Most biological research with application to conservation requires fieldwork, and fieldwork on animals involves a variety of