Mediterranean Fin Whales Research Articles

Targeting fin whale conservation in the North-Western Mediterranean Sea: insights on movements and behaviour from biologging and habitat modelling.

Biologging and habitat modelling are key tools supporting the development of conservation measures and mitigating theeffects of anthropogenic pressures on marine species. Here, we analysed satellite telemetry data and foraging habitat preferences in relation to chlorophyll-a productivity fronts to understand the movements and behaviour of endangered Mediterranean fin whales (Balaenoptera physalus) during their spring-summer feeding aggregation in the North-Western Mediterranean Sea. Eleven individuals were equipped with Argos satellite transmitters across 3 years, with transmissions averaging 23.5 ± 11.3 days. Hidden Markov Models were used to identify foraging behaviour, revealing how individuals showed consistency in their use of seasonal core feeding grounds; this was supported by the distribution ofpotential foraging habitat. Importantly, tracked whales spent most of their time in areas with no explicit protected status within the study region. This highlights the need for enhanced time- and place-based conservation actions to mitigate the effects of anthropogenic impacts for this species, notably ship strike risk and noise disturbance in an area of exceptionally high maritime traffic levels. These findings strengthen the need to further assess critical habitats and Important Marine Mammal Areas that are crucial for focused conservation, management and mitigation efforts.

Song Notes and Patterns of the Mediterranean Fin Whale (Balaenoptera physalus) in the Ionian Sea

The Mediterranean fin whale emits two types of 20-Hz calls, known as “classic” and “backbeat”, that can be produced in irregular series or in patterned sequences called songs. The analysis of songs is recognized as a meaningful approach to study baleen whales and can be used to investigate populations’ identities. Mediterranean fin whale songs have been studied previously, but only in the western Mediterranean Sea. This work describes the structure of the songs recorded in the Ionian Sea. The inter-note intervals and the alternation of 20-Hz note types were considered to assess the occurrence of recurring patterns. Differences between patterned songs and irregular sequences were also investigated. Acoustic data were sampled continuously for about 10 months by the cabled observatory NEMO-SN1, deployed at 2100 m depth, 25 km offshore Catania; 28 call sequences were isolated and 10 of these were classified as either patterned songs or irregular sequences. Significant differences were observed in the spectral features of classic notes between songs and irregulars; four-note patterns were found repeatedly over different months, indicating a regular structure in detected songs. This work establishes a reference to interpret Mediterranean fin whale songs, and to assess the acoustic behavior of the population.

Fin whales (Balaenoptera physalus) summering in the Ligurian Sea: distribution, encounter rate, mean group size and relation to physiographic variables

This paper investigates the distribution of Mediterranean fin whales (Balaenoptera physalus) between 1990-99 in the recently-established Pelagos Sanctuary for the Conservation of Mediterranean Marine Mammals. During the study period, 870 days were spent at sea, surveying a total of 73,046km, totalling 540 sightings of fin whales. Mean yearly whale encounter rates showed no significant differences in the first five years, but then steadily decreased between 1995-99. The highest encounter rates and largest mean aggregation size (mean=2.12; SD=1.32; SE=1.15) were in summer 1995 and the mean aggregation size throughout the study period was 1.75 (mode=1; SD=1.11; SE=0.05). Differences in mean aggregation size were significant between years, but not months. This is likely to be related to prey availability and to patchiness of plankton distribution. Generalised Linear Models were used to relate fin whale distribution to physiographic variables (mean, range and standard deviation of depth and slope, and distance from the nearest coast). Water depth was the most significant variable in describing fin whale distribution, with more than 90% of sightings occurring in waters deeper than 2,000m. This study demonstrates the deep water preference of fin whales in this area, emphasises the crucial role that this part of the western Ligurian Sea plays in the ecology of Mediterranean fin whales and provides recommendations for conservation and management measures in the area.

Estimating the impact of ship strikes on the Mediterranean fin whale subpopulation

The Mediterranean fin whale (Balaenoptera physalus) subpopulation is under threat from collisions with ships. Given the international dimension of the issue, the French, Italian, Monegasque and Spanish governments have proposed a Particularly Sensitive Sea Area (PSSA), i.e., a management zone of the International Maritime Organization (IMO), in which mandatory and voluntary protective measures can be implemented. Defining the risk and its impact at the subpopulation level is required to improve the chances of an IMO acceptance for such a proposal. While previous research partially succeeded in defining the collision risk, its impact on the subpopulation has not been thoroughly evaluated, especially at the spatial scale of the envisioned PSSA. Our study uses the carcass recovery approach to estimate the number of deadly collisions within the proposed PSSA. We then assess the probability that this number exceeds three management rules: Potential Biological Removal (PBR), Alert Reference Point (ARP) and Critical Reference Point (CRP). These management rules describe thresholds beyond which (a) the incidental mortality may prevent the recovery of the population within 100 years (PBR), (b) there is a cause for concern about incidental mortality (ARP), and (c) there is a critical need to lower the incidental mortality (CRP). We conclude that mortality from collisions alone is in excess of PBR. Taking into account confirmed and suspected collisions in strandings in calculations, the collision mortality exceeds ARP; this threshold being considered unacceptable by some international organisations. Additionally, there is almost a 35% chance that the mortality due to ship strikes exceeds the CRP, likely resulting in a population decline. The probability of anthropogenic mortality exceeding CRP is 60% if we include the fishery-related mortality in stranding (i.e., taking into account the total incidental mortality from bycatch and ship strikes). The PSSA proposal could use our approach to estimate the impact of collisions and assess the effectiveness of implemented protective measures. However, it is important to highlight that the IMO process for establishing a PSSA is lengthy, and our findings show that immediate action is required, as there is a high probability that the ship strike and fishery mortality is beyond the critical threshold fixed by the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic area (ACCOBAMS).

Abundance of fin whales (Balaenoptera physalus) in the north‐western Mediterranean Sea, using photo‐identification and microsatellite genotyping

AbstractThe Mediterranean fin whale population, Balaenoptera physalus, is resident, with almost no exchanges with the Atlantic population. The entire population was estimated at 1300 or 13,300 individuals by a recent project depending on the platform used. This disparity shows the importance of long‐term monitoring with a unique protocol of survey. Capture‐recapture approaches using dorsal photographs and genetic identity collections over a 10 years period were used to estimate the abundance of the north‐western Mediterranean fin whale. We identified 332 individuals using photographs and 470 using genotypes, with a total of 546 individuals identified between 2008 and 2019, when some whales were double‐marked. The inter‐annual percentage of recapture varied between 15% and 17% respectively for genotypes and photographs methods. Using Cormack‐Jolly‐Seber models, the abundance of fin whales in the north‐western Mediterranean is estimated at 1295 individuals (95% CI: 1116–1474) with a survival probability of 0.945 (95% CI: 0.690–0.993) from genotypes. Abundance estimates from combined collections (photographs and genotypes) and corrected photograph estimates were similar to the genetic ones. Future studies might prioritize the genetic approach which is the least biased and with a narrower confidence interval. The genetic abundance estimates show relative stability over time, when compared to 1990 estimates, and should be included in future conservation actions.

Analysis of environmental, social, and anthropogenic factors as potential drivers of breaching behavior in the Mediterranean fin whale

AbstractBreaching is frequently reported for many large cetacean species, but this behavior is considered very rare in fin whales (Balaenoptera physalus). Fin whales are regularly observed in the Mediterranean Sea, and they perform seasonal concentration/dispersal movements throughout this basin. This study aimed to investigate the influence that environmental parameters, social factors, and anthropogenic disturbance may have on breaching behavior in fin whales to deepen the understanding of these displays. Fin whale sightings were collected between 2012 and 2020 within the Fixed Line Transect Monitoring Network along the ferry route from Italy to Spain, crossing the mid‐latitudes of the western Mediterranean Sea. Breaching events were analyzed with respect to season, chlorophyll concentration, sea state, group size, fin whale frequency, distance between a breaching event and the closest whales, distance from the observation platform, and maritime traffic. During the study, breaching events were recorded 27 times over 721 fin whale sightings (3.74%), with a higher frequency during summer and fall (>4.96%) compared to spring (1.77%); no events were observed during winter. The most significant variables were distance from the observation platform as an inhibitory factor and distance between whales, possibly related to socialization and communication.

Nothing is as it seems: genetic analyses on stranded fin whales unveil the presence of a fin-blue whale hybrid in the Mediterranean Sea (Balaenopteridae)

The fin whale Balaenoptera physalus is a large rorqual species occurring worldwide, mainly in temperate and subpolar zones. In contrast to many baleen whales, not all the fin whale populations show the same model of migration. In fact, migratory behaviours of this latter species range from long seasonal migration between high and low latitudes to a complete non-migratory behaviour. A resident fin whale population was described in the Mediterranean Sea, which is also frequented by North Atlantic individuals entering through the Strait of Gibraltar in winter to feed. Between 2020 and 2021 three individuals initially identified as fin whales died along the Tyrrhenian coasts (Mediterranean Sea, Italy). Their mitochondrial DNA control region (mtDNA CR) was analysed and compared to fin whale haplotypes previously described in North Atlantic Ocean and Mediterranean Sea to identify their geographical origin. Our results show that two individuals most likely belong to the Mediterranean fin whale population, while an individual was recognised as a putative fin-blue whale hybrid (Balaenoptera physalus x Balaenoptera musculus) with a North Atlantic origin. The discovery of the first fin-blue whale hybrid in the Mediterranean Sea was confirmed by the analysis of a biparentally inherited marker, the α-lactalbumin (α-lac) nuclear gene, demonstrating that the morphological analysis alone does not allow to correctly identify hybrids, especially if intermediate characters of both parental species are not clearly distinguishable.

Cost-effectiveness of measures to reduce ship strikes: A case study on protecting the Mediterranean fin whale

Collisions between ships and whales can pose a significant threat to the survival of some whale populations. The lack of robust and holistic assessments of the consequences of mitigation solutions often leads to poor compliance from the shipping industry. To overcome this, several papers support a regulatory approach to the management of whale-ship collisions through the International Maritime Organization (IMO), the UN agency responsible for maritime affairs. According to the IMO risk assessment approach, in order to compare the costs of implementing mitigation solutions and their benefits, there is a need for a well-defined risk evaluation criterion. To define such a criterion for whales, we have used an ecological-economic framework based on existence values and conservation objectives. As an illustration, we have applied our framework to the Mediterranean fin whale (Balaenoptera physalus) population and determined the cost of averting a whale fatality as a proxy for the societal benefits. More precisely, we have estimated the ‘Cost of averting a Mediterranean fin whale fatality’ of 562,462 (in 2017 US dollars); this corresponds to 637,790 USD when converted to 2021 US dollars. The societal benefits of solutions that reduce the risk to whales could therefore be weighed against the costs of shipping companies to implement such measures. This could lead to assessments that are more transparent and the introduction of mandatory measures to reduce ship strikes.

Skin distress associated with xenobiotics exposure: An epigenetic study in the Mediterranean fin whale (Balaenoptera physalus).

The phenotypic plasticity of many organisms is mediated in part by epigenetics, the heritable changes in gene activity that occur without any alterations to DNA sequence. A major mechanism in epigenetics is the DNA methylation (DNAm). Hypo- and hyper-methylation are generalized responses to control gene expression however recent studies have demonstrated that classes of contaminants could mark specific DNAm signatures, that could usefully signal prior environmental exposure. We collected skin and blubber from 6 free-ranging fin whale (Balaenoptera physalus) individuals sampled as a part of a previous published study in the northern Mediterranean Sea. Genomic DNA extracted from the skin of the fin whales and levels of contaminants measured in the blubber of the same individuals were used for DNAm profiling through reduced representation bisulfite sequencing (RRBS). We tested the hypothesis that differences in the methylation patterns could be related to environmental exposure to contaminants and load in the whale tissues. The aims of this study were to determine the DNAm profiles of the methylation contexts (CpGs and non-CpGs) of differently contaminated groups using the RRBS, and to identify potential contaminant exposure related genes. Amount and proportion of methylcytosines in CpG and non-CpG regions (CHH and CHG) was very similar across the 6 samples. The proportion of methylcytosines sites in CpG was n=32,682, the highest among all the sequence contexts (n=3216 in CHH; n=1743 in CHG). The majority of the methylcytosine occurred in the intron regions, followed by exon and promoter regions in CpG, CHH and CHG. Gene Ontology results indicated that DNAm affected genes that take place in cell differentiation and function in cutaneous, vascular and nervous systems. The identification of cellular response pathways allows a better understanding of the organism biological reaction to a specific environmental challenge and the development of sensitive tools based on the predictive responses. Eco-epigenetics analyses have an extraordinary potential to address growing issues on pollution biomonitoring, ecotoxicity assessment, conservation and management planning.

Parasitological and pathological findings in fin whales Balaenoptera physalus stranded along Italian coastlines

Mediterranean fin whales Balaenoptera physalus face many threats to their conservation, including both anthropogenic and natural issues. There are few records of the parasitic fauna of this species in this geographical area. To partially fill in this gap of knowledge, we investigated the presence and potential impact of parasitic diseases in Mediterranean fin whales. Seven animals stranded along Italian coastlines between 2006 and 2015 were submitted for necropsy and parasitological examination. The protozoan parasite Toxoplasma gondii was detected in 1 fin whale and, for the first time in mysticetes, it was successfully genotyped as a type II strain with 15 microsatellite markers. One crustacean (Pennella spp.) and 4 helminth taxa (Crassicauda boopis, Ogmogaster antarcticus, Tetrabothrius ruudi and Bolbosoma sp.) were detected and morphologically identified. Different degrees of ectoparasitism by adult P. balaenoptera were recorded. Immature stages of Pennella sp. were also detected in 2 animals and are described here for the first time in cetaceans. Infestation by C. boopis was confirmed or suspected in 5 cases. Parasitic thrombi, involving renal veins and caudal vena cava, and fibrosis of renal parenchyma were associated with C. boopis and likely resulted in some degree of renal dysfunction. Larval nematodes were found within foci of mesenteric endarteritis. Further research to evaluate the prevalence of this potentially fatal endoparasitosis in Mediterranean fin whales is warranted.

Satellite tagging of Mediterranean fin whales: working towards the identification of critical habitats and the focussing of mitigation measures

Mediterranean fin whales comprise a genetically distinct population, listed as Vulnerable (VU) in the IUCN Red List. Collisions with vessels are believed to represent the main cause of human-induced mortality. The identification of critical habitats (including migration routes) incorporating satellite telemetry data is therefore crucial to develop focussed conservation efforts. Between 2012 and 2015 thirteen fin whales were equipped with satellite transmitters, 8 in the Pelagos Sanctuary (although two ceased within two days) and 5 in the Strait of Sicily, to evaluate movements and habitat use. A hierarchical switching state-space model was used to identify transiting and area-restricted search (ARS) behaviours, believed to indicate foraging activities. All whales undertook mid- to long-distance migrations, crossing some of the world’s busiest maritime routes. Areas where the animals predominantly engaged in ARS behaviour were identified in both study areas. The telemetry data were compared with results from ecosystem niche modelling, and showed that 80% of tagged whale positions was near (<7 km) the closest suitable habitat. The results contribute to the view that precautionary management should include establishment of a coordinated and dynamic basin-wide management scheme; if appropriate, this may include the establishment of protected areas by specific regional Conventions.

Isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic)

The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly in deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology.The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic).δ13C and δ15N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea.δ13C and δ15N values ranged from −20.4 to −17.1‰ and from 5.9 to 8.9‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences.One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts.

Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus)

Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990–‘92 and the 2006–‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells.

Mysticete migration revisited: are Mediterranean fin whales an anomaly?

Abstract The generally accepted model of Mysticete whale migration is that most individuals undertake seasonal migrations between high and low latitudes. Although numerous exceptions have been described in the literature, the traditional model remains unexamined. This paper represents the first ‘official’ challenge to the traditional model of Mysticete migration. We set out to review the current state of knowledge on the Mediterranean fin whale migratory pattern, and to examine whether the small, resident population in the Mediterranean is an anomaly within the framework of the traditional model of Mysticete migration. We investigated the prevalence of alternative migratory strategies among the Mysticete whales, reviewing the migratory habits of the Mediterranean fin whales and those of other fin whale and baleen whale populations. We reach three main conclusions. First, the seasonal behaviour of the resident Mediterranean fin whales is highly dynamic, and a decade of research has not clarified prevailing uncertainties regarding migration patterns. Second, migration strategies similar to those observed in the Mediterranean fin whales are commonly seen in other populations of baleen whales. Third, the traditional model of whale migration is too simplified to describe the repertoire of Mysticete migratory behaviours accurately. We argue that the paradigm of baleen whale migration warrants further scrutiny to account for more complex movement strategies. We suggest that Mysticete migration should be thought of as a continuum of different strategies that have evolved in the face of different selective pressures. Instead of representing an exception to the rule, the resident Mediterranean fin whales may in fact fall towards one end of a larger spectrum of migratory behaviours. A greater knowledge of ecological factors, reproductive patterns, and local adaptations will be needed to understand the evolutionary mechanisms behind the diversity of migratory habits.

Fin Whales, Balaenoptera physalus: At Home in a Changing Mediterranean Sea?

Abstract 1. The relationship of Mediterranean fin whales ( Balaenoptera physalus ) to their Atlantic conspecifics has puzzled zoologists for centuries. Recent data indicate the occurrence of two distinct populations, one resident in the Mediterranean Sea and the other a seasonal visitor to the western Mediterranean from the northeastern North Atlantic Ocean. 2. Resident Mediterranean fin whales are nomadic opportunists that have adapted to exploit localised mesoscale hotspots of productivity that are highly variable in space and time. These appear to be fairly widespread across the region during winter, whereas in summer favourable feeding habitat is dramatically reduced, concentrating mostly in the western Ligurian Sea and Gulf of Lion. This prompts a reinterpretation of the movement pattern of resident fin whales, based on a contraction/dispersion hypothesis caused by seasonal variability in available feeding habitat, as opposed to a pattern of migrations occurring along defined directions as is common in other Mysticetes. 3. Calving peaks in autumn but has been observed year-round throughout the Mediterranean, suggesting that resident fin whales engage in breeding activities whenever favourable physiological conditions occur. It can be assumed that the Mediterranean environment, which is relatively forgiving in comparison to oceanic habitats, combined with negligible predation pressure and high potential for sound-mediated socialisation due to the region's relatively small size, might have provided year-round resident fin whales an extended and more flexible calendar of breeding and feeding opportunities. 4. Considering the Mediterranean fin whales’ small and possibly decreasing population size, low survival rate and the high pressure from many threats deriving from human activities such as vessel traffic, noise, chemical pollution and likely climate change, their status raises considerable concern and conservation measures should be urgently implemented.

Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily, Central Mediterranean Sea.

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.

Pb Isotopic Compositions of Fin Whale Baleen Plates – A Clue to Unravel Individual Migrations between the Atlantic Ocean and the Mediterranean Sea?

To assess Mediterranean fin whale ecology and impacts of environmental changes, Pb content and isotopic composition were measured on baleen plates of fin whales stranded on Mediterranean and Bay of Biscay coasts. Pb contents of fin whale baleen plate reflect that of their diet and thus of the dissolved Pb content of the upper 200 meters of the surface ocean. Using Pb isotopes, baleen plates allow reconstituting the evolution of anthropogenic Pb pollution and showing that stranded Mediterranean fin whales constitute a specific population that is resident of the Mediterranean Sea with occasional migrations to the Atlantic Ocean.

A network approach to migratory whale conservation: Are MPAs the way forward or do all roads lead to the IMO?

The objective of this paper was to analyse the challenges and prospects of regional MPA networks as an effective tool for the protection of wide-ranging cetaceans, focusing on the potential of the Specially Protected Areas of Mediterranean Importance (SPAMI) network initiative to contribute to the conservation of the Mediterranean fin whale (Balaenoptera physalus). One of the main threats to this vulnerable population is mortalities through ship strikes. It is argued that a SPAMI network does not have the potential to effectively reduce the threat of ship strikes on a firm legal, scientific and political basis, particularly given uncertainty over fin whale seasonal movements. Instead, an alternative sectoral approach to landscape-scale protection is discussed. Building on examples from North America, it is proposed that a wider spatial scale threat-based approach should be adopted, and that a regional network of restrictions of shipping activities through the International Maritime Organisation (IMO) will more effectively reduce the risk of ship–whale strikes. This is also more consistent with the ecosystem approach, since the emphasis is on ecological scales that cross administrative boundaries, even though it is within a single sector. It is concluded that mechanisms exist to address the challenges of implementing such an approach, and that sectoral measures through the IMO represent an important way forward for improving the conservation prospects for Mediterranean fin whales.

Large filter feeding marine organisms as indicators of microplastic in the pelagic environment: The case studies of the Mediterranean basking shark (Cetorhinus maximus) and fin whale (Balaenoptera physalus)

The impact of microplastics (plastic fragments smaller than 5 mm) on large filter feeding marine organisms such as baleen whales and sharks are largely unknown. These species potentially are ingesting micro-litter by filter feeding activity. Here we present the case studies of the Mediterranean fin whale (Balaenoptera physalus) and basking shark (Cetorhinus maximus) exploring the toxicological effects of microplastics in these species measuring the levels of phthalates in both species. The results show higher concentration of MEHP in the muscle of basking shark in comparison to fin whale blubber. These species can be proposed as indicators of microplastics in the pelagic environment in the implementation of Descriptor 8 and 10 of the EU Marine Strategy Framework Directive (MSFD).

Stable isotope analysis of baleen reveals resource partitioning among sympatric rorquals and population structure in fin whales

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 479:251-261 (2013) - DOI: https://doi.org/10.3354/meps10231 Stable isotope analysis of baleen reveals resource partitioning among sympatric rorquals and population structure in fin whales Conor Ryan1,*, Brendan McHugh2, Clive N. Trueman3, Richard Sabin4, Robert Deaville5, Chris Harrod6,7, Simon D. Berrow1,8, Ian O?Connor1 1Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland 2Marine Institute, Rinville, Oranmore, County Galway, Ireland 3Ocean and Earth Science, University of Southampton, National Oceanography Centre, European Way, Southampton SO14 3ZH, UK 4Vertebrates Group, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK 5UK Cetacean Strandings Investigation Programme, Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK 6School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Queen’s University Belfast, Belfast BT9 7BL, UK 7Instituto de Investigaciones Oceanológicas, Universidad de Antofagasta, Avenida Angamos 601, Antofagasta, Chile 8Irish Whale and Dolphin Group, Merchant’s Quay, Kilrush, County Clare, Ireland *Email: conor.ryan@iwdg.ie ABSTRACT: Stable isotope analysis is a useful tool for investigating diet, migrations and niche in ecological communities by tracing energy through food-webs. In this study, the stable isotopic composition of carbon and nitrogen in keratin was measured at growth increments of baleen plates from 3 sympatric species of rorquals (Balaenoptera acutrostrata, B. physalus and Megaptera novaeangliae), which died between 1985 and 2010 in Irish and contiguous waters. Bivariate ellipses were used to plot isotopic niches and standard ellipse area parameters were estimated via Bayesian inference using the SIBER routine in the SIAR package in R. Evidence of resource partitioning was thus found among fin, humpback and minke whales using isotopic niches. Highest δ15N values were found in minke whales followed by humpback, and fin whales. Comparison between Northeast Atlantic (Irish/UK and Biscayan) and Mediterranean fin whale isotopic niches support the current International Whaling Commission stock assessment of an isolated Mediterranean population. Significantly larger niche area and higher overall δ15N and δ13C values found in fin whales from Irish/UK waters compared to those sampled in adjacent regions (Bay of Biscay and Mediterranean) suggest inshore foraging that may be unique to fin whales in Ireland and the UK. Isotopic profiles support spatial overlap but different foraging strategies between fin whales sampled in Ireland/UK and the Bay of Biscay. Stable isotope analysis of baleen could provide an additional means for identifying ecological units, thus supporting more effective management for the conservation of baleen whales. KEY WORDS: Diet · Isotopic niche · Foraging · Stock discrimination · Northeast Atlantic · Bayesian analysis Full text in pdf format PreviousNextCite this article as: Ryan C, McHugh B, Trueman CN, Sabin R and others (2013) Stable isotope analysis of baleen reveals resource partitioning among sympatric rorquals and population structure in fin whales. Mar Ecol Prog Ser 479:251-261. https://doi.org/10.3354/meps10231 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 479. Online publication date: April 08, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.