MethodologyScientific basisData and methods
Insufficient data are available to perform an analytical stock assessment. Data analyses are based on trends in landings, commercial cpue data, and biological knowledge.
Information is the same as in 2006 and 2007, with updated landings data and survey data from VIa. Preliminary lpue data are available for IXa in 2008 (Figures 18.104.22.168 and 22.214.171.124).Data and methods
Data from the French fishing industry has been used in the data analyses (Figure 126.96.36.199).Uncertainties in assessment and forecast
Landings data on these species remain very problematical. For many countries, data are only available for combined deepwater (“siki”) sharks. Many countries continue to report landings in generic categories such as “various sharks nei”. Retrospective splitting of the data into species categories could result in inconsistencies.
Fishery-independent data covers only a small area and a short time-series.Comparison with previous assessment and advice
There is no information that changes the perception of the stock since last year.
Experimental assessments using production and depletion models were conducted by ICES in 2000 and 2002. In 2000, the combined stock of these species in Subareas V, VI, and VII was estimated to be depleted, below Upa
and possibly below Ulim
. In 2002, additional data were incorporated, and the strong decline in stock abundance was still evident. In 2002, upward trends in French trawler cpue were reported. Evidence available in 2006 showed that this trend was due to a movement of the fishery to new grounds within Subareas V and VI and did not reflect changes in stock abundance.