Nephrops in the Bay of Biscay and Iberian Waters (FU23-24), Demersal otter trawl

Nephrops norvegicus
Content last updated
23 January 2018
Stock
Nephrops in ICES Division VIIIa, b (FU23-24)
Management
EU
Stock Status
3 of 5
Moderate risk
Management
3 of 5
Moderate risk
Bycatch
4 of 5
High risk
Habitat
5 of 5
Very high risk

Stock status

3 of 5
Moderate risk

The status of the Nephrops stock in Division VIIIab (FU23-24) has been scored a moderate risk. The species has a low vulnerability score of 14/100 (Pauly and Palomares, 2014), and the stock size indicator from the most recent assessment shows a decline since 2016. However fishing mortality is estimated to be below FMSY reference point.

Management

3 of 5
Moderate risk

The management of Nephrops in Division VIIIa,b (FU23-24) has been scored a moderate risk. This is because management decisions are based on a data-limited stock assessment undertaken biennially for functional units 23-24 combined, landings of Nephrops have exceeded the advised catch in two out of the last ten years, and catch advice is provided for the entire Division which results in difficulties in managing fishing effort in multiple functional units with varying population trends. Surveillance is generally effective with adequate enforcement and compliance.

Bycatch

4 of 5
High risk

The bycatch in the demersal otter trawl fishery has been scored a high risk. This is because bycatch and discard rates are high in demersal otter trawls targeting Nephrops due to the small cod end mesh requirements of the target species. However, measures to reduce bycatch and discards in these fisheries have been the subject of much research over the years. This research has resulted in the introduction of technical measures to improve the selectivity of the fishing gear, which in turn have been implemented as a statutory requirement. Further measures, such as modified trawl designs, have been implemented on a non-statutory basis.  

Habitat

5 of 5
Very high risk

The habitat impact of the demersal otter trawl fishery has been scored a very high risk. This is because demersal otter trawls interact with seabed habitats resulting in abrasion and penetration from ground gear, sweeps and bridles. Some spatial overlap exists between fishing activities and areas colonised by benthic invertebrate communities, and no spatial management has been established to limit interactions between demersal otter trawls and vulnerable marine habitats.   Changes in the biodiversity of these areas have been associated with trawling. There is a process in place under the OSPAR convention and UK Marine Acts to avoid adverse impacts through the designation of Marine Protected Areas.