© Krzysztof Skora, Hel Marine Station

Accidental entanglement in fishing gear is generally considered the most serious threat to cetacean populations in the ASCOBANS area. Every year, thousands of animals are trapped in fishing nets, preventing them from coming up to the surface to breathe. Due to their inshore distribution and benthic feeding habits, harbour porpoise populations are especially vulnerable to bycatch in set net fisheries, in particular trammel nets and set gillnets. Other gear types, such as pelagic trawl fisheries targeting tuna, bass and hake and fisheries using very high vertical opening (VHVO) trawls are of concern in the North East Atlantic especially with regard to other cetacean species, such as common dolphins.

ASCOBANS has long recognized bycatch as the most significant threat to the small cetacean populations in the Agreement Area and resolutions addressing this problem have been passed repeatedly at Meetings of the Parties. These resolutions address the monitoring programmes and mitigation measures required in order to understand the situation and reduce mortality of cetaceans.

A working group on bycatch has been established by the Advisory Committee. More information on the tasks of the Group and its reports can be found here. Bycatch is also one of the major points of discussion in the regional working groups on the harbour porpoise action plans under ASCOBANS, namely the Jastarnia Group and the North Sea Group.

There is no comprehensive information on the bycatch of cetaceans in EU waters. Almost all of the EU gillnet fisheries in the North Sea are conducted without bycatch monitoring programmes, and no recent estimates of total porpoise bycatch (or that of any other marine mammal) exist. Regular updates of the status of knowledge are prepared by the International Council for the Exploration of the Sea (ICES) Working Group on Bycatch of Protected Species (WGBYC), and in ICES assessments and advice (available on the ICES website). The available data indicates, however, that the annual bycatch rate for harbour porpoises in all parts of the Agreement Area is significantly above the 1.7% limit for total anthropogenic removal (which includes bycatch as well as other human-induced causes of mortality) set by ASCOBANS. This means that bycatch rates alone are already likely to cause a population decline, which means that the objective of the Agreement to achieve a favourable conservation status for small cetaceans is most likely not being met. Besides the population impacts, bycatch is also a major animal welfare concern, as animals that became entangled suffer injuries while desperately trying to free themselves and eventually asphyxiate.

Also the Convention on Migratory Species, under which ASCOBANS was concluded, gives bycatch a high priority, and the Conference of the Parties has passed a number of resolutions on the subject (see e.g. Res.9.18 and Res.10.14). The Scientific Council has an Appointed Councillor for Bycatch, who not only provides expert advice on the matter but also takes the lead in liaison with RFMOs and the monitoring of relevant research and technological developments.


Recommendations of ASCOBANS on the Requirements of Legislation to Address Monitoring and Mitigation of Small Cetacean Bycatch

The European Union has acknowledged bycatch as the most serious threat and adopted a number of regulations introducing mitigation measures with the aim of reducing bycatch, such as phase out of driftnets in the Baltic Sea, introduction of the widespread use of pingers and others. In particular Regulation (EC) 812/2004 sets down measures concerning incidental catches of cetaceans in European fisheries.

Noting that “the Commission shall no later than 31 December 2015 review the effectiveness of the measures laid down in this Regulation and accompany this review with an overarching legislative proposal for ensuring the effective protection of cetaceans”, the ASCOBANS Advisory Committee in 2014 (AC21) concluded that an expert workshop should be held, involving the relevant stakeholders (EU, fisheries organizations, scientists, etc.) in order to develop the position of ASCOBANS on the legislation required to address small cetacean bycatch and monitoring. The main aim of the workshop was to produce a report with clear and detailed recommendations of requirements for revised/new legislation. 

The two-day workshop was held in Bonn, Germany, from 21-23 January 2015. The report of the meeting, including its recommendations, is available as AC22/Inf.4.1.a.  Upon request of the Jastarnia Group (JG11, Stralsund, Germany, 10-11 March 2015), the relevant ASCOBANS working groups (Baltic Sea, North Sea, Atlantic and Bycatch) were then given opportunity to provide their views on the recommendations of this workshop (Annexes 3-7 of the report).  A statement combining the views of three of the working groups is available as AC22/Inf.4.1.b.

Using this additional input, as well as taking into account the recommendations of the workshop on “Further Development of Management Procedures for Defining the Thresholds of Unacceptable Interactions”, held in London, UK, on 10 July 2015, a revised version was presented to the 22nd Advisory Committee Meeting (AC22/Doc.4.1.b). In subsequent discussions, it was further refined and on 30 October 2015 the result of these processes was transmitted to the European Commission.  The recommendations are available here.


ASCOBANS Conservation Objectives and “Unacceptable Interactions”

The ASCOBANS Conservation and Management Plan, under the heading “Habitat conservation and management” coins the term “unacceptable interaction”, which has triggered extensive work under the Agreement, especially in the 1990s.

Two resolutions passed in 2000 (Resolution 3.3 on Incidental Take of Small Cetaceans) and 2006 (Resolution 5.5 on Incidental Take of Small Cetaceans), both still extant, set out the key conclusions reached in this process:

a)     “the aim of ASCOBANS can be interpreted as "to restore and/or maintain biological or management stocks of small cetaceans at the level they would reach when there is the lowest possible anthropogenic influence"” (Res.3.3)

b)     “a suitable short-term practical sub-objective” “to restore and/or maintain stocks/populations to 80% or more of the carrying capacity” (Res.3.3)

c)      “the general aim should be to minimise (i.e. to ultimately reduce to zero) anthropogenic removals within some yet-to-be-specified time frame, and that intermediate target levels should be set” (Res.3.3 and Res.5.5)

d)     “defines, for the present, according to the most recent scientific information "unacceptable interactions" as being, in the short term, a total anthropogenic removal above 1.7 % of the best available estimate of abundance” (Res.3.3)

e)     “underlines the intermediate precautionary objective to reduce by-catches to less than 1% of the best available population estimate” (Res.3.3 and Res.5.5)

f)      “if available evidence suggests that a population is severely reduced, or in the case of species other than the harbour porpoise, or where there is significant uncertainty in parameters such as population size or by-catch levels, then "unacceptable interaction" may involve an anthropogenic removal of much less than 1.7 %” (Res.3.3.)

In 2013, the United Kingdom presented AC20/Doc.3.1.2 Societal decisions required for the determination of safe bycatch limits for harbour porpoise, common dolphin and bottlenose dolphin, which noted that the ASCOBANS conservation objective “to allow populations to recover to and/or maintain 80% of carrying capacity in the long term” stands, but requires some key policy decisions in order to become fully applicable.  In particular, ‘society’ should decide on parameters scientists should use, such as:

·       Whether the conservation objective should be met on average or some other percentage of the time (>50%)

·       The timeframe over which it should be applied (e.g. 100 years, 200 years, another period)

·       The spatial areas to which the procedure is to be applied (i.e. appropriate management units)

A working group was formed in order to assist the Advisory Committee in addressing these questions.  In 2014, AC21 decided to hold two workshops, the first of which was to develop a shared understanding on the use of thresholds/environmental limits and took place on 10 July 2015 in London, United Kingdom (“Part I”, see the report as AC22/Inf.4.1.c). The key outcomes of this workshop are also reflected in the recommendations sent to the European Commission referred to above.

AC22 agreed the terms of reference for the next workshop, which will be announced on this website in due course.


ASCOBANS Workshop on Remote Electronic Monitoring with Regards to Bycatch of Small Cetaceans

The main aim of the workshop, held on 2 October 2015, was to develop best practice guidance on the use of cameras on boats for bycatch monitoring. Participants discussed challenges and ways to overcome them with respect to topics such as stakeholder involvement, acceptance by fishermen, practical and technical issues of installation, data processing etc. The report and recommendations are available here.