Discards monitoring in the Gillnet Sole Fishery

The Gillnet Sole Fishery Study Group started discards monitoring. Data were supposed to be collected in three different ways: Self-sampling, catch monitoring by means of onboard cameras (CCTV) and monitoring under the Data Collection Regulation

Data availability for the evaluation of stock status of species without catch advice: Case study: turbot (Psetta maxima) and Brill (Scophthalmus rhombus)

Several commercially important demersal fish stocks for the North Sea fisheries are classified as “category 11” in the light of the EU policy paper on fisheries management (17 May 2010, COM(2010) 241). For stocks in this category, there is no STECF (Scientific, technical and economic committee for fisheries ) management advice, due to the unknown status of the stocks. The reason for this is that the data and information available to perform analytical stock assessments are highly uncertain or lacking. This document describes existing data and options for collecting new data for the evaluation of the state of category 11 stocks. We focus on turbot and brill in the North Sea. Existing data from logbooks and the market sampling program can be used to estimate LPUE series used in age-based stock assessment methods, similar to other commercially important flatfish species such as plaice and sole. Landings Per Unit of Effort (LPUE) data of the Dutch beam trawl fleet > 221 kW were standardised for engine power and corrected for targeting behaviour as described below and graphically shown in Figure 3.2.1. The methods are similar to those used to analyse commercial LPUE data for North Sea plaice, described in Quirijns and Poos (2010). Landing rates (LPUE) by market category were calculated for the period 2002-2010. The corrected LPUE series indicate an increase in commercial LPUE for both species during the period 2002-2006. For turbot, the LPUE stays stable in the first five years, increases between 2006 and 2008, and decreases afterwards. The increase in brill LPUE is larger, and occurs throughout the study period. Compared to other commercially important flatfish species relatively few brill and turbot market samples are taken. This reduces the ability to track the cohorts in the LPUE series of the older ages which is a prerequisite for reliable stock assessment estimates. Also, the time series currently spans only 9 years. Collection of additional data may therefore be desirable. Expanding the BTS survey will provide industry independent data and would therefore give easily interpretable results. The option of an industry survey is also a good option if the survey is already being executed for sole and plaice. However, both options are costly. Therefore, the option of increasing the samples of turbot and brill at the auction is relatively easy and relatively inexpensive and therefore at present the most promising. The methods used for this document will not per definition be applicable for all category 11 species. For dab, flounder, lemon sole and tub gurnard, samples at the auctions are taken to collect biological data. For these species it may be possible to raise the data in a similar way as was done in this report to estimate the age composition of the stock. For other species (witch flounder, horse mackerel, silver smelt, red mullet and squid) there is no market sampling. For these species, other methods will have to be developed

Discards monitoring in the Gillnet Sole Fishery

The Gillnet Sole Fishery Study Group monitored discards since 2011. This document describes results from the self-sampling. No observer trips in the Dutch Sole Gillnet Fishing have taken place under the EU data collection framework (DCF). Under the DCF The Netherlands are obliged to sample ten gill net fishing trips. However, it is not specified which type of gill net fishing trips should be sampled, i.e. no target species is specified. In 2011 observers only went on board gill net trips in which cod was targeted. In 2012, up to November 2012, no observer trips were carried out in these fisherie

Kennisdocument rode poon, mulen inktvis

Van een aantal doelsoorten in de flyshootvisserij – rode poon, mul en inktvis – is weinig bekend over de ontwikkelingen in de bestanden en de vangsten. In dit kennisdocument wordt daarom de beschikbare informatie over deze soorten op een rij gezet. Hiervoor zijn Nederlandse visserijgegevens en surveygegevens gebruikt

Brede visie op duurzame visserij in de Waddenzee

Het Waddengebied is een uniek natuurgebied, de visserij is een belangrijke economische activiteit in dat gebied, wat vraagt om een visie voor de toekomst. In opdracht van het Regionaal College Waddengebied (RCW) (waarin zitting hebben: drie Waddenprovincies, de Waddengemeenten, de waterschappen langs de Waddenzee en het Rijk) is een visie voor het gebied opgesteld

Discards in fisheries - a summary of three decades of research at IMARES and LEI

Discards and the possible ecological and economic effects of discarding are a hot topic in discussions about sustainable fisheries. The perception of the effects of discarding differs between parties and it is influenced by the ecosystem functioning and the state of the species under consideration. This report provides an overview of the current scientific knowledge at IMARES and LEI about discard levels, effects, and discard reduction from an ecological, technical, economic and management perspective. The following Dutch commercial marine wild capture fisheries with active gear are considered: pelagic, beam trawl, otter trawl (demersal fish and nephrops) and shrimp fisheries

Staandwantvisserij op platvis en kabeljauw

In de staandwantvisserij gebruiken vissers netten die verankerd zijn op de bodem. De staandwantvisserij is een passieve visserij; vissen worden gevangen doordat ze verstrikt raken als ze erdoorheen proberen te zwemmen. Deze informatiebrochure gaat over de staandwantvisserij gericht op tong en de staandwantvisserij met grotere mazen gericht op kabeljauw of platvis. Er zijn ongeveer 60 (kleine) vaartuigen die zich bezighouden met deze visserijen

Fisheries Data Collection from September - December 2002

Vangst- en inspanningsgegevens van de commerciële vissersvloot kunnen worden gebruikt bij het verbeteren van bestandsbepalingen. De gegevens die tot nu toe zijn verzameld worden in 2003 gecorrigeerd voor factoren die het vangstsucces beïnvloeden zoals motorvermogen, weersomstandigheden, diepte enzovoorts. Ondanks de verminderde medewerking van vissers, functioneert de technische opzet van het project goed. Een grote hoeveelheid gegevens is reeds verzameld en zal erg bruikbaar zijn bij het ontwikkelen van het vangstsucces als indicator voor veranderingen in de visbiomassa

Memo: Naar een Rijke Visstand - Inventarisatie

Inventarisatie naar de bestaande kennis over (1) de huidige toestand van de visgemeenschap in de Waddenzee en Noordzeekustzone (2) alsmede naar het staande en toekomstige beleid relevant voor dit onderwerp

Inventory of current and future presence of non-wind sea use functions

In order to assess the suitability of locations on the Central and Southern North Sea for wind parks present sea use functions should also be taken into account. These sea use functions comprise shipping, oil and gas extraction, fisheries, cables and pipelines, military activities, sand extraction, radar interference and nature conservation. IMARES has collected data on these other sea use functions. Data was gathered from several national institutions, with a good deal of help from our project partners in identifying the best available sources