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Balaenoptera physalus 

Scope: Mediterranean
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Balaenopteridae

Scientific Name: Balaenoptera physalus
Species Authority: (Linnaeus, 1758)
Infra-specific Taxa Assessed:
Regional Assessments:
Common Name(s):
English Fin Whale, Common Rorqual, Finback, Fin-backed Whale, Finner, Herring Whale, Razorback
French Baleine à nageoires, Baleine fin, Baleinoptère commune, Rorqual Commun
Spanish Ballena Aleta, Ballena Boba, Rorcual Común
Taxonomic Notes: The subspecific phylogeny of Fin Whales has not yet been fully elucidated, but some authors recognize a northern hemisphere subspecies B. p. physalus and a southern hemisphere subspecies B. p. quoyi which has a larger body size. Clarke (2004) proposed a pygmy subspecies B. p. patachonica Burmeister, 1865, but this is not widely accepted and no genetic analysis has been performed.

Assessment Information [top]

Red List Category & Criteria: Vulnerable C2a(ii) (Regional assessment) ver 3.1
Year Published: 2012
Date Assessed: 2010-04-20
Assessor(s): Panigada, S. & Notarbartolo di Sciara, G.
Reviewer(s): Perrin , W. & Taylor, L.
Justification:

The Red List assessment for the Mediterranean subpopulation of Fin Whale requires the following considerations:

  • The Mediterranean subpopulation, which is genetically distinct from fin whales in the Atlantic, contains fewer than 10,000 mature individuals;
  • The subpopulation experiences an inferred continuing decline in number of mature individuals;
  • All mature individuals are in one subpopulation.

No population estimate exists for the entire region. However, line-transect surveys in 1991 yielded Fin Whale estimates in excess of 3,500 individuals over a large portion of the western Mediterranean (Forcada et al. 1996), where most of the basin’s Fin Whales are known to live. It is reasonable to assume that a realistic estimate for the total basin would not exceed 5,000 individuals, so the threshold of 10,000 (for Vulnerable under criterion C) is met.

Human-induced mortality from vessel collisions and bycatch in fishing gear (Panigada et al. 2006), together with the potential effects of the disturbance caused by growing whale watching activities, lead to the inference that the subpopulation is declining. Fin Whales have been described as particularly abundant during the summer months in the Corso-Ligurian-Basin, which is considered their major feeding ground in the Mediterranean Sea. A sharp decrease in Fin Whale abundance has been observed in the Pelagos Sanctuary over the last decade, with estimates of 900 individuals reported from the western Ligurian Sea in 1992 (Forcada et al. 1995), declining to significantly lower numbers (N=147; CV=27.04%; 95% CI=86–250) in 2009 (Panigada and Lauriano pers. comm.). While the sharp decrease of Fin Whales in the Pelagos Sanctuary may be due to whales relocating elsewhere within the Mediterranean, their decrease in prime Fin Whale habitat must be addressed with precaution, and a population decline in the Mediterranean cannot be discounted at this time.

Fin Whales in the Mediterranean are a subpopulation based on the IUCN definition. Palsbøll et al. (2004) suggested an estimate of 0.33 migrant/year between Mediterranean and Atlantic). Genetic data from a sample of Fin Whales from the Mediterranean have not provided evidence for within-region subpopulation structure (Bérubé et al. 1998); Fin Whales, known as a highly mobile species, are thought to roam widely across the Mediterranean, and the assumption that they form a single subpopulation within the basin is the most parsimonious. Should future research reveal that Fin Whales in the Mediterranean are structured into western and eastern subpopulations, this would involve the splitting of the current subpopulation into two even smaller designatable units, possibly subjected to higher levels of vulnerability and threats.

Geographic Range [top]

Range Description:Fin Whales are regularly encountered throughout the western and central Mediterranean basins, with seasonal summer concentrations in highly productive portions of the Corsican, Ligurian and Tyrrhenian seas, where they apparently feed on a single euphausiid species, Meganyctiphanes norvegica (Orsi Relini et al. 1998). Limited evidence exists of similar feeding activities in the eastern Ionian Sea (Notarbartolo di Sciara et al. 2003). Seasonal (late winter) feeding aggregations of Fin Whales have also been observed recently in the Sicily Channel (Canese et al. 2006). Photo-identification data imply a high degree of site fidelity in fin whales summering in the Ligurian Sea (Zanardelli et al. 1998). Breeding and calving grounds have yet to be identified (Notarbartolo di Sciara et al. 2003). Fin Whales are extremely rare in the Adriatic and Aegean Seas and in the Levantine Basin.
Countries occurrence:
Native:
Algeria; Cyprus; Egypt; France; Gibraltar; Greece; Israel; Italy; Lebanon; Libya; Malta; Monaco; Morocco; Spain; Syrian Arab Republic; Tunisia; Turkey
FAO Marine Fishing Areas:
Native:
Mediterranean and Black Sea
Additional data:
Range Map:2478-3

Population [top]

Population:Forcada et al. (1996) estimated 3,583 fin whales (S.E. 967, 95% C.I. 2,130–6,027) in a large portion of the western Mediterranean in 1991, and Forcada et al. (1995) estimated 901 individuals (S.E. 196.1, %CV 21.77, 95% C.I. 591–1,374) in the Corsican-Ligurian-Provençal Basin in 1992. A survey carried out in the entire Pelagos Sanctuary area yielded an estimate of 715 individuals (%CV 31.2, 95% C.I. 421–1,215), with highest values in the Ligurian-Provencal area (Gannier 2006). Two aerial surveys organized in winter and summer 2009 in the whole Pelagos Sanctuary area yielded 0 and 17 fin whale sightings respectively, resulting in an estimate of Fin Whale abundance for the summer of 147 individuals (%CV=27.04; 95% CI=86–250) (Panigada and Lauriano, pers. comm.). This indicates that Fin Whales in this area may be less abundant than previously reported (Forcada et al. 1995, Gannier 2006).

A sharp decrease in fin whale abundance has been observed in the Pelagos Sanctuary over the last decade, with estimates of 900 individuals reported from the western Ligurian Sea in 1992 (Forcada et al. 1995), declining to significantly lower numbers (N=147; CV=27.04%; 95% CI=86–250) in 2009 (Panigada and Lauriano pers. comm.). While the sharp decrease of Fin Whales in the Pelagos Sanctuary may be due to whales relocating elsewhere within the Mediterranean, their decrease in prime Fin Whale habitat must be addressed with precaution, and a population decline in the Mediterranean cannot be discounted at this time.

Genetic analyses based on both mitochondrial and nuclear DNA indicated differences between the Mediterranean population, which is thought to be resident, and Fin Whales in Atlantic coastal waters of Canada, Greenland, Iceland and Spain (Bérubé et al. 1998). Further genetic analyses (Palsbøll et al. 2004) predicted that Mediterranean Fin Whales would prove to be largely resident in the basin, although limited but recurrent gene flow was detected in the data. Palsbøll et al. (2004) estimated the effective number of female migrants between the Mediterranean Sea and the Eastern North Atlantic to be 0.33 migrant/year, a value that is consistent with the IUCN definition for subpopulation (i.e., IUCN 2001) and fatty acid analysis, suggesting that Fin Whales summering in the Ligurian Sea may spend the winter in Spanish Atlantic waters, returning during spring and summer to the Mediterranean Sea (Ruchonnet et al. 2006).

No population estimates exist for the entire region. However, line-transect surveys yielded estimates of 3,583 Fin Whales (S.E. 967, 95% C.I. 2,130–6,027) over a large portion of the western Mediterranean in 1991 (Forcada et al. 1996) and 901 (S.E. 196.1, 95% C.I. 591–1,374) in the Corsican-Ligurian-Provençal Basin in 1992 (Forcada et al. 1995). Further line-transect survey effort in the same area yielded a strikingly consistent density estimate of 0.015 individuals km-2 (Gannier 1997).
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Fin Whales in the Mediterranean are most common in deep waters (400–2,500 m), but they can occur in slope and shelf waters as well, depending on the distribution of their prey (Gannier et al. 2002; Laran and Gannier 2008; Notarbartolo di Sciara et al 2003; Panigada et al. 2005, 2008). They favour upwelling and frontal zones with high zooplankton concentrations, their main prey in the region. Habitat-use results show that cetacean distribution in the western Ligurian Sea may change in response to climate variability, with fin whales avoiding areas with extreme sea-surface temperature (SST) values (different from the monthly average) (Azzellino et al. 2008).
Systems:Marine

Use and Trade [top]

Use and Trade: In the Mediterranean Sea, this species is not utilized.

Threats [top]

Major Threat(s): Although each impacting factor may not be seen as a major threat when considered alone, the cumulative effects of these in a semi-enclosed basin heavily affected by human presence (such as the Mediterranean) is interpreted in a precautionary manner to amount to potentially large and detrimental effects on both birth and death rates and might explain the observed localized decline.

Incidental mortality of Fin Whales in fishing gear (pelagic driftnets) is uncommon (Podestà and Magnaghi 1989) and its effect on the population is therefore considered low but not negligible (International Whaling Commission 1994).

Ship strikes also cause mortality and are a concern particularly in areas of heavy vessel traffic (Cagnolaro and Notarbartolo di Sciara 1992, Panigada et al. 2006, Weinrich et al. 2006). The increasing use of high-speed ferries requires further investigation in this regard.

Shipping noise and vessel disturbance, particularly from the unregulated whale watching that has recently begun in the area (Airoldi et al. 1999), is another source of concern. Other vessel traffic may cause additional acoustic stress. Seismic airguns can deter Fin Whales from feeding or breeding grounds (Castellote et al. 2009), with potential detrimental effects on the population.

There is no competition between Fin Whales and fisheries in the Mediterranean because in this region fin whales are almost exclusively planktophagous (Notarbartolo di Sciara et al. 2003).

Fossi et al. (2002, 2003) described high levels of contamination by organochlorines, trace elements and DDT metabolite values in Mediterranean Fin Whales, and suggested that their estrogenic and anti-androgenic effects may negatively influence the population. Fossi et al. (2007) presented evidence of endocrine disrupting chemicals (EDCs) in Fin Whale biopsy samples from the western Ligurian Sea, which may adversely affect the reproductive functions of these whales.

This subpopulation is largely dependent on euphausiids species, such as M. norvegica, N. couchii, for food (Notarbartolo di Sciara et al. 2003), which possibly are susceptible to climate changes. Therefore the potential effects of global climate change or ocean acidification on Fin Whales in the Mediterranean currently are unknown, but cannot be neglected and need further investigation.

Conservation Actions [top]

Conservation Actions: A large international protected area (approx. 90,000 km²), the Pelagos Sanctuary for Mediterranean Marine Mammals, was recently established and listed among Special Areas of Mediterranean Importance (SPAMIs) (Barcelona Convention SPA Protocol) and encompasses a key Fin Whale feeding area in portions of the Provençal, Corsican, Ligurian, Tyrrhenian and northern Sardinian Seas (Notarbartolo di Sciara et al. 2008). Whale-watching regulations are likely to be incorporated into national legislation in the near future.

The species is listed in Appendix I of CMS, in Appendix II of the Bern Convention, in Appendix I of CITES, and in Annex 2 of the Protocol on Specially Protected Areas and the Biological Diversity in the Mediterranean of the Barcelona Convention. For the present at least, Mediterranean Fin Whales are protected by the International Whaling Commission’s moratorium on commercial whaling that came into force in 1986.

Citation: Panigada, S. & Notarbartolo di Sciara, G. 2012. Balaenoptera physalus. The IUCN Red List of Threatened Species 2012: e.T2478A2787161. . Downloaded on 26 July 2017.
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