Europe and Central Asia
2 May 2016

Running against the clock to save Europe’s most threatened seabird

The Balearic Shearwater is difficult to study as its breeding grounds are often inaccessible. Photo: Ricardo Guerreiro
By Marguerite Tarzia

Seabirds are currently recognised as one of the most threatened groups of birds. Within Europe, one species is particularly at risk of extinction: the Critically Endangered Balearic Shearwater.

Although its migration occurs along the highly populated Atlantic coast (including to Portugal, France and southern UK), this long lived seabird has been notoriously difficult to study, especially since its breeding grounds on the Spanish Balearic Islands are often inaccessible. Ten years ago, the alarm was raised by scientists with a study predicting that the species was on track to become extinct in approximately 40 years. In 2004, the population was estimated to only number 2.000 breeding pairs.

Predation of eggs and chicks by invasive predators such as rats was known to occur, however it was the very low survival of adult birds that was suspected as the main cause of the species’ spiralling descent towards extinction.

Apart from predation by cats in certain colonies, it was suggested by scientists and SEO/BirdLife (BirdLife in Spain) that the main cause of adult deaths was the accidental capture in fishing gear bycatch. Scientific information was lacking, however to directly link bycatch to population declines.

Sporadic bycatch of the species has been recorded on many occasions, with the most problematic gear being demersal longlines (using long fishing lines with baited hooks along the sea floor to catch fish) in the Spanish Mediterranean. SPEA (BirdLife in Portugal) identified that birds were also being caught in other fishing gears during their Atlantic migration.

Since 2004 there have been a number of initiatives, both in Spain and internationally, to try and reverse the population trend of this species. These include an International Species Action Plan (compiled by SEO/BirdLife and BirdLife International), the identification of marine Important Bird and Biodiversity Areas (IBAs; and their subsequent protection as Natura 2000 sites), tracking and mapping of migratory movement and management of invasive predators at colonies.

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But most of these advances have occurred only on paper; conservation action on the ground has been very weak. Consequently, the population of the Balearic Shearwater continued to decline.

In March 2016, a new study on the demography of the species was published, the result of a collaborative effort between research institutions and with the involvement of SEO/BirdLife. The paper provided an updated estimate of the population and its long term survival. Currently estimating a population of 20.000-30.000 individuals, the equivalent of over 7.000 pairs of breeding birds, and using over 30 years of monitoring data, the research predicted that extinction is likely to occur in ~60 years.

This might look as an alarmist prediction, but in fact it’s very conservative: although the model assumes a breeding population of over 7,000 breeding pairs, counts on the ground (though subject to biases) suggest a lower figure, around 3.200 pairs.

This doesn’t mean the Balearic Shearwater has improved its conservation status or increased in numbers. Rather it shows an improvement in the techniques to estimate and model the population’s viability. Giving us very little time to reverse this trend and prevent the species’ extinction, this paper provides scientific evidence that it is the bycatch of adult birds that is leading to the steep population decline.

Aware of the urgent need to understand the episodic nature of the bycatch of this species, SEO/BirdLife and BirdLife International (through the generous support of Fondation Segré) began working with the fleet of vessels fishing along the Catalan coast (in the same area as the Balearic Shearwater foraging grounds).

The Seabird Task Force, a team of seabird bycatch experts, began working in 2014 to understand the reasons why birds were caught at certain times and not others, and to improve solutions alongside the fishing fleet.

Our focus during 2016 is to understand the specific way in which the fishing gear works, and the reasons why it is catching seabirds. Following this, we will try to adapt known solutions for the fishing vessels to reduce, and hopefully eliminate, bird bycatch. This work coincides with EU-wide efforts to better record seabird bycatch and implement mitigation measures (such as changes to gear and scaring devices).

If viable solutions are put in place, with the support from both the fishing industry and the government, there is hope for a possible way forward to protect this species into the future. 

Stichting BirdLife Europe gratefully acknowledges financial support from the European Commission. All content and opinions expressed on these pages are solely those of Stichting BirdLife Europe. The European Commission is not responsible for any use that may be made of the information it contains.