North Spanish fisheries: discards, causes and reduction measures
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1
Instituto Español de Oceanografia, Centro Oceanográfico de Vigo, Spain
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2
Instituto Español de Oceanografía, Centro Oceanográfico de Murcia, Spain
It is widely accepted that discards are a waste of resources from the perspective of the exploited stocks and from a macro-economic human perspective. The European Union Commission, Parliament, and many stakeholders, are concerned that the current discarding levels in the fisheries under European jurisdiction are high. There is thus a strong commitment to reduce the discards of European fisheries by enforcing the landing obligation of the unwanted catch. The European Common Fisheries Policy (CFP) aim to eliminate the discards of managed species over the next few years.
In Iberian waters, some fishing fleets currently discard a significant proportion of their catch – up to 70% in weight for some trawler fleets. In the case of a discard-limiting regulation, these fleets would face the requirement to seriously alter their practices so as to reduce their discards. This can be achieved by reducing unwanted catches, by landing a larger proportion of the unwanted bycatch that is currently discarded, or by a combination of the two
The discard patterns in Iberian fisheries exhibit a high diversity across regions, countries, gear types, vessel sizes, and species, and that discards amounts, patterns, and composition, are determined by a multitude of interacting natural and human (economic and social) factors in a given place and time, and usually no simple explanation can suffice. The findings from several European Research Projects suggest that as discarding is in most cases an unavoidable consequence of a series of constraints on the fishing activities and production, managing discards implies taking account of the whole fishery management system.
The objetives of this work aims are to understand the patterns reasons for discarding in the North Spanish waters (ICES Divisions VIIIc and IXa) and to identify measures to eliminate discards.
The Spanish bottom trawl operating in the Northern and Western coastal waters (ICES Divisions VIIIc and IXa) is prosecuted by vessels with 28 m of average length. This fleet is composed of otter trawlers and pair trawlers.
“Baca” gear (OTB_DEF_>=55_0_0) target demersal species, standing out hake (Merluccius merluccius), megrims (Lepidorhombus boscii and L. whiffiagonis) and anglerfish (Lophius piscatorius and L. budegassa). Vessels from Galicia (A Coruña, Burela, Celeiro, Corme, Marin, Muros, Muxia, Ribeira, Vigo), Asturias (Avilés, Gijón) and Cantabria trawl for demersal species all year round on the continental shelf and upper slope from southern Bay of Biscay to northwest Spanish Iberian waters.
The pair bottom trawl fleet (PTB_MPD_>=55_0_0) target blue whiting (Micromesistius poutassou), hake and mackerel (seasonally). The fleet from 3 ports in Galicia (Ribeira, Celeiro y Burela) and Aviles (Asturias) operates on the continental shelf and upper slope of NW Spanish waters and Cantabrian Sea.
The main causes of discarding are two: fish discarded below the legal minimum landing size and discards that can be attributed to fishers’ responses to quota restrictions (including highgrading). The remainder of discards included species with low or no market value, which were not worth landing given the high value of the target species. To develop successful discard mitigation measures, it is necessary to better identify the reasons for discarding.
Over the past ten years several pilot projects aboard commercial vessels have tested selectivity trawl gears, including square meshes and changes on mesh size and geometry. The selectivity projects have been carried out by Instituto Español de Oceanografia (IEO) working together with fisheries companies and associations. Pilot projects set up the theoretical selectivity measures and selectivity trails have been conducted focus on square mesh, mesh netting geometry and mesh size able to balance the roundfish by-catch avoidance.
Most of the selectivity results have not been implemented. Only legal regulation on minimum mesh size have change gears. Due to the mixed nature of trawling fisheries the selectivity changes have limited efficacy and easy to use in practice. Fishermen do not want to use new fishing nets that may interfere or pose significant changes in their way of fishing and produce an unwanted efficacy on catching the target species but also bycatch of several valuable species.
Currently several temporal or permanent spatio closures exist in northwest Iberian waters and it will be difficult to reach an effective agreement to close new areas. Despite this, some progress could be expected using real-time closures to avoid high discarding areas, specially choke-species areas.
Acknowledgements
The authors acknowledge IEO SAP Program and REDDISC Project. This work was made within the LIFE + iSEAS Project eLIFE13 ENV/ES/000131).
Keywords:
Discards,
landing obligation,
Trawl Fishery,
bycatch,
Fisheries Management
Conference:
XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016.
Presentation Type:
Poster Presentation
Topic:
4. FISHERIES, AQUACULTURE AND BIOTECHNOLOGY
Citation:
Valeiras
J,
Abad
E,
Santos
M and
Bellido
J
(2016). North Spanish fisheries: discards, causes and reduction measures.
Front. Mar. Sci.
Conference Abstract:
XIX Iberian Symposium on Marine Biology Studies.
doi: 10.3389/conf.FMARS.2016.05.00198
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Received:
15 May 2016;
Published Online:
03 Sep 2016.
*
Correspondence:
PhD. Julio Valeiras, Instituto Español de Oceanografia, Centro Oceanográfico de Vigo, Vigo, 36390, Spain, xulio.valeiras@vi.ieo.es