Report of the Benchmark Workshop on Flatfish Species and Anglerfish (WKFLAT), 1–8 March 2012, Bilbao, Spain.
|Ref.||ICES CM 2012/ACOM:46. 283 pp.|
|Sponsor||CIEM / ICES|
|Abstract||WKFLAT 2012 met from 1st to 8th March 2010 at AZTI Derio (Bilbao) Spain. The meeting was chaired by Joanne Morgan (Canada) and ICES co-ordinator was Rob Scott (UK). Rick Methot (USA) and Paul Nitschke (USA) participated in the meeting as invited external experts. A total of 25 participants from nine countries were in at-tendance. Stakeholder representatives were in attendance for part of the meeting.
The main goals and objectives of the meeting were to compile and evaluate data sources for stock assessment, investigate assessment models suitable to provide in-formation on stocks status and to update the relevant stock annexes of seven stocks as necessary. These included a number of anglerfish stocks (Anglerfish (Lophius piscato-rius) (Divisions VIIb–k and VIIIabd), Anglerfish (Lophius budegassa) (Divisions VIIb–k and VIIIabd), Anglerfish (Divisions IIa and IIIa, Subarea IV and Subarea VI), Angler-fish (L. piscatorius) (Divisions VIIIc and IXa), Anglerfish (L. budegassa) (Divisions VIIIc and IXa)), Sole in Division VIIe and Megrim in Divisions VIIb–k and VIIIabd. For each stock the preferred stock assessment method was determined and the stock an-nexes updated with the agreed procedures for generating and collating the input data to the stock assessment and the methods for estimating and forecasting stock status. In addition issues related to ageing and stock structure of anglerfish were discussed.
Part of the problem with producing acceptable assessment models for anglerfish was data quality and a lack of knowledge of some of the basic biological processes for these species. There is a lot of uncertainty about maturity, sex ratio, growth, and length frequencies of the catch and there needs to be an improvement in these data.
The main results of the meeting stock were:
Use of ageing in anglerfish assessments: The use of illicia based ageing was not war-ranted for either species. For Lophius piscatorius the studies of growth of Landa et al. (2012) should be used as the basis for length based assessments. For anglerfish in Divisions IIa and IIIa, Subarea IV and Subarea VI, ageing based on otoliths exists and age based assessments could be considered for this stock if the internal consistency of the age composition of the data were examined in more detail and sensitivity to growth assumptions considered. Further growth and (ageing) age validation studies taking sex into account are required.
Anglerfish stock structure: There is no clear biological evidence to support the man-agement and assessment units as they are now. Tagging experiments and other stock structure studies are encouraged to determine if the migratory rate between areas is low enough not to impair the assessment models that consider the current stocks as isolated populations with little movement.