Where have the Fin whales gone? Absence from Biscay feeding grounds alarms watchers

A crossing of the Bay of Biscay usually spots 50-100 Fin whales, but they have seen less than 5 this year. Photo credit Marinelife.

Alarm bells ringing for fin whale absence

September 2009. Two leading whale and dolphin research charities, Marinelife and Organisation Cetacea(ORCA), are concerned that the annual summer migration of Fin Whales into the eastern Bay of Biscay has failed to materialise this year, raising wider concerns for the health of this important ecosystem.

Marinelife, through its project the Biscay Dolphin Research Programme (BDRP) and ORCA have been researching whales and dolphins in the Channel and Bay of Biscay for many years and each year they have recorded a two phase immigration of Fin Whales into the Bay of Biscay, where they spend the spring and summer months feeding on schooling fish and krill. During the late autumn, the Fin whales leave Biscay and spend the winter elsewhere. Whilst further research is needed to prove where they migrate to, the Irish Whale and Dolphin Group (IWDG) have been recording Fin whales off of southern Ireland during late autumn and winter for a number of years, suggesting a westerly movement.

Marinelife chairman and wildlife officer Clive Martin said: "We are concerned that the Fin whales have not yet returned to Biscay this year in their usual high numbers. They initially arrived in small numbers in May but, their numbers have not increased through July and August as has been recorded in previous years."

Normally 50 -100 Fin whales normally seen
Clive Martin went onto say: "At this time of year, on a return crossing from Portsmouth to
Bilbao on P&O's Pride of Bilbao we would normally see 50 - 100 Fin whales, yet on the last few crossings, we have been seeing less than 5."

Low numbers of Fin whales have also been recorded by the Portuguese marine mammal organisation CEMMA (Coordinadora para o Estudio dos Mamíferos Mariños). Dylan Walker from ORCA has also contacted other whale and dolphin researchers working in the Atlantic to determine if Fin whales are being seen elsewhere in higher than normal numbers.

Fin whales are usually much more common in the Bay of Biscay. Photo credit Marinelife.

Biscay important feeding ground for Fin whales
Biscay appears to be an important feeding ground for Fin whales and their absence rings alarm bells for both BDRP and ORCA as this could be an indication of losses in fish stocks and other food sources due to over-fishing, or ecosystem disturbance due to climate change. BDRP previously raised concerns with the EU fisheries commission about low dolphin numbers in Biscay in 2007 which coincided with the continued failure of the anchovy fishery which, according to the EU fisheries commission, still remains in a state of collapse and is showing no signs of recovery, prompting the EU Fisheries commission to implement a long term conservation policy to safeguard the future sustainability of the anchovy fishery in Biscay.

Marinelife Research Director Dr Tom Brereton commented: "Our ongoing research in Biscay and our partnership with other European research organisations through ARC, allows us to very quickly identify short term and longer term changes in whale and dolphin distribution. This absence of Fin Whale at a time of year when their numbers have previously been high could simply indicate a late arrival or usage of a richer feeding ground elsewhere this year, but could equally signal issues with fish stocks in Biscay."

BDRP and ORCA will continue to monitor the Biscay Fin whale population with the hope that they are just late arriving this year. Their ongoing long-term monitoring work is vital in helping to understand year round habitat usage and the extensive database of sightings information is a valuable resource for the designation of protected areas for marine wildlife and to assess climate change impacts on biodiversity.