Working Group on Bycatch of Protected Species (WGBYC)

Sara Bonanomi, Maurice W. Clarke, Bram Couperus, Christian von Dorrien, Peter Evans, Ruth Fernandez, Nicole Hielscher, Katarzyna Kamińska, Allen Kingston, Sven Koschinski, Finn Larsen, Ana Marçalo, Hélène Peltier, Carlos Pinto, Maris Plikshs, Guðjón Már Sigurðsson, Adam Wozniczka

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Six Terms of Reference (ToRs; Annex 2) were addressed during the meeting through plenary and subgroups. The 2019 report is structured in the same order as the ToRs. Contributions to ToRs were requested in advance of the meeting and all data submissions were requested via a formal WGBYC/ICES data call (Annex 7). The data call requested data on fishing effort, monitoring effort and protected species (marine mammals, seabirds, reptiles and fish) bycatch incidents in 2017. Of the 24 countries contacted, 20 responded to the data call. Many countries continue to submit data late (one-third) and the quality of the data submissions is variable. The data call referred to bycatch of fish, as per the list provided in Table 1D of the Commission Implementing Decision (EU) 2016/1251 adopting a Multiannual Union Programme (EU-MAP); however, WGBYC this year reviewed this list to create a priority fish bycatch list since many of the species on D1 are commercially caught and other scientific bodies, e.g. ICES expert groups, carry out assessments for these. Member States (MS) reports on the implementation of Regulation 812/2004 during 2017 were reviewed. Most MS continue to monitor protected species bycatch using fisheries observers conducting sampling under the Data Collection Framework (DCF); only a few countries have a dedicated bycatch observer programme. With the upcoming repeal of Regulation 812/2004 in 2019, WGBYC will in future receive its data from monitoring under EU-MAP. Monitoring of smaller vessels (<15m) in the European fleet has to date generally been poor, and sampling designs under EU-MAP need to ensure representative coverage of relevant metiers for protected species bycatch. In 2017, bycatch records from the datacall included 148 cetaceans (5 species); 63 seals ( 4 species), 528 birds (22 species); 97,816 elasmobranchs (49 species) and 15 turtles (2 species) .. Equivalent data from non-EU countries was also received from the USA and Iceland. MS’s compliance with the pinger requirements of Regulation 812/2004 is difficult to gauge from the submitted reports, as there are reporting inconsistencies and in-complete information. Only the UK appears to comply fully and reported that all relevant vessels are equipped with “DDD” pingers used under a derogation and there is active enforcement in place. But in general, there has been little progress in the mitigation of cetacean bycatch and the effectiveness of pingers appears to vary between with fishing metiers and geographical areas. WGBYC completed Bycatch Risk Assessments (BRA) for harbour porpoise and grey seals in the Celtic Seas (CS) and Greater North Sea (NS) ecoregions. Data were pooled from 2015-2017 and minimum and maximum bycatch rates extrapolated using 2017 fishing effort data for nets, bottom trawls and pelagic trawls. Bycatch rates of both species were highest in nets in both ecoregions; however, French data also included a high number of seal bycatch incidents in bottom trawls, but these records could not be verified during the meeting. The percentage mortality of the grey seal population in the CS and NS ecoregions due to bycatch was estimated at 1.5 - 2.8%. For harbour porpoise, in the NS between 0.33 - 0.59% in nets, and in the CS between 0.29 - 0.8% in nets and bottom trawls combined; both of these estimates are below the ASCOBANS 1.7% threshold defining unacceptable levels of interaction and below the 1% precautionary environmental limit. However, ICES ecoregions are arbitrary and are unlikely to reflect true population structure of harbour porpoise; the working group therefore conducted a further BRA using the latest definition of a Celtic Sea subpopulation and this suggested that levels of mortality in 2017 due to bycatch may be between 2.12 - 5.57% of that subpopulation. This demonstrates the importance of assessing population level impacts at appropriate spatial scales. It also worth noting that most of the observation data comes from DCF monitoring which likely biases bycatch rates downward. Additional estimates of harbour porpoise and common dolphin bycatch mortality based on stranding data were also presented for the North Sea and Bay of Biscay/English Channel as WGBYC continue to assess the performance of those methods for estimating by-catch levels. For the first time, WGBYC prepared comprehensive summaries of elasmobranch and seabird data from 2017, and calculated lower and upper confidence intervals around the bycatch rates using the available monitoring data. For both taxa, the main focus was placed on species of higher perceived conservation concern. Access to monthly fishing effort data was considered an important prerequisite for usefully extrapolating seabird bycatch data because of the seasonality in bycatch rates (driven by seasonality in seabird distribution and behaviours). Calculated confidence intervals around seabird bycatch rates were wide; though precision levels could be improved upon in future by generating multi-annual bycatch rates in or-der to utilise more data. Elasmobranch bycatch was very common in all ecoregions. The range of bycatch rates presented highlight those species, gears and areas where bycatch may be a particular concern; the data also contribute usefully to a more general scientific understanding of the distribution and abundance of some elasmobranch species. WGBYC has made considerable progress forming relationships with other ICES expert groups; the relationship established with WGEF should help facilitate the work of both groups going forward. WGBYC also undertook a review of the risk assessment being used by the Regional Coordination Groups to develop regional sampling plans under EU-MAP. An exercise comparing levels of dedicated bycatch monitoring versus DCF monitoring effort in North Atlantic fishing grounds, high-lighted the trivial amount of dedicated PS monitoring days undertaken in 2017. In the North Sea for example, there were just 22 days of dedicated bycatch monitoring compared to 1829 days monitoring under the DCF. WGBYC conducted a comparative analysis of the 2017 effort data contained within the WGBYC database with equivalent data from the ICES Regional Database. Significant differences were highlighted between the datasets from individual countries, gear and vessel size categories. Neither database was consistently better than the other, however, reliance solely on the RBD as the source of fishing effort data in future would require that all countries submit data to it in a usable format for WGBYC bycatch assessments (e.g. the UK’s submission to the RBD could not be used in the comparative analysis because the UK did not provide effort to the RDB as “days at sea” which is not currently a mandatory field. Historically “days at sea” has been the common metric provided through Regulation 812/2004 reports and thus enables pooling of national datasets to estimate overall bycatch rates. WGBYC has collated bycatch monitoring and fishing effort data since 2005. To date, the requests for these data and the required reporting format have gradually evolved. This presents challenges to using the entire dataset as data from the early years are not fully compatible with more recent years. WGBYC began the process of making the entire dataset usable this year but this requires further work. However, this is an invaluable exercise that will maximise the value of the dataset by providing a significant time series of data which will enable the group to look at inter-annual trends in bycatch rates by metier and area. This ongoing process will also identify core fields and data needs that will be required in future data calls and from the RDB, to ensure ongoing compatibility. It is of paramount importance to the work of WGBYC that the transition from using data from Regulation 812/2004 data collection and data storage structures can be accommodated in the RDB (and upcoming RDBES) so that the full time series is maintained and available for analysis.
Original languageEnglish
PublisherInternational Council for the Exploration of the Sea (ICES)
Number of pages171
Publication statusPublished - 2019
SeriesICES Scientific Report


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