A fp7 Project: Management and Monitoring of Deep-sea Fisheries and Stocks wp2 – Template for Case Study Reports Case study 2 demersal deep-water mixed fishery Pascal Lorance, Ifremer, Nantes (coord.)
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- 3.7.2. What were the outcomes for the latest benchmark/update assessment and for all exploratory assessments
- Black scabbardfish in V, VI, VII, XII
- Portuguese dogfish and the leafscale gulper sharks
- 3.7.3. How could assessments be improved in terms of the data used and the methods used
- Portuguese dogfish and leafscale gulper shark
- 3.7.4. What additional data and information would be required
3.7. Quality control/peer review3.7.1. Were the assessments subjected to quality appraisal and/or peer review and if so how and by whom?Assessments are presented during the ICES expert group WGDEEP plenary session and reviewed by the experts attending the working group. After the expert group meeting, the ICES framework includes a review group which reviews all assessments carried out by the expert group. To used the outcome from the assessment to deliver a scientific advice for management there is an advice drafting group and a web conference. 3.7.2. What were the outcomes for the latest benchmark/update assessment and for all exploratory assessments?Roundnose Grenadier Vb, VI, VII, XIIbThis species presents major assessment challenges largely driven by: life history characteristics (long lived (ca. 60 years) and slow growing), changes in exploitation pattern resulting from changes in the geographical and depth distribution of trawl fisheries in relation to stock distribution, a lack of fisheries independent survey data, and discontinuity in the availability of time series discard data (fisheries on this stock generate high discards) and of age data. Abundance indices based on French trawl catch and effort logbook data are available but their use in assessments is problematic because of changes in spatial and depth distribution of fishing and also changes fleet composition/fishing power. Time series of length distribution data are available for French trawl landings. Time series haul by haul data on catch and effort by French trawlers, collected in collaboration with the industry, is now available from year 2000-2009. The members of the ICES Method Working group 2009 recommended not using any length or age based methods for roundnose rrenadier in Vb, VI, VII and XIIb but rather focusing on production models or effort based approaches such trends on effort using for example the industry haul by haul database. Another suggested approach is to develop a life-stage based model. One recurring criticism is also the use of SVPA for a long-lived species with only 19 years of data. The adopted assessment model at the ICES WKDEEP benchmark workshop was a Bayesian surplus production model (based on Pella Tomlinson biomass dynamic model). This approach, only considered as indicative of trends, was selected as it was considered as the most parsimonious approach with respect to the the lack of data and short time series. Black scabbardfish in V, VI, VII, XIISome alternative methods to stock assessments to estimate stock trends are necessary. Possible options for a benchmark include refining LPUE calculation from EU-Logbook data, use additional data. For this latter, the French tallybooks database seem to be an interesting opportunity as it is more accurate than EU logbooks, being haul by haul and including data on fishing depth (ICES WGDEEP, 2009). Greater forkbeardThis is a gadoid species and is considered to likely exhibit typical gadoid life history characteristics, although these are not known with any accuracy. Commercial landings are significant but this almost entirely a bycatch species taken in other fisheries. The stock depletion model presented at the ICES WKDEEP benchmark was considered exploratory. Portuguese dogfish and the leafscale gulper sharksLeafscale gulper sharks is long lived (up 60 years). There is no data on age of Portuguese dogfish but longevity is presumed similar. Length and age data are not available and historical landings data are not available by species (although in recent years the quality of landings data has improved). Haul by haul data from French trawlers fishing in Vb, VI and VII by species back to the mid 1990s were made available in 2008. No fishery for these species is currently not permitted but deep-water sharks are still taken as a bycatch of fishing for other species and are discarded. Due to the ban of landings of deep-waters sharks, data on catch are disrupted, only on-board observations and surveys will now provide data on these species. An exploratory model presented at the ICES WKDEEP benchmark is under development by IPIMAR. Surplus production model is considered as a potential candidate for leafscale gulper shark but not assessment has been carried out so far. 3.7.3. How could assessments be improved in terms of the data used and the methods used?Roundnose Grenadier Vb, VI, VII, XIIb
Black scabbardfish in V, VI, VII, XII
Greater forkbeard
Portuguese dogfish and leafscale gulper shark
3.7.4. What additional data and information would be required?Roundnose Grenadier Vb, VI, VII, XIIbFor roundnose grenadier, levels and size distribution of discards at the beginning of the fishery would be useful. Nevertheless, only limited archive data might be available Black scabbardfish in V, VI, VII, XIIThe time-series of LPUE from French tallybook allows assessing recent trends. It could be used in a surplus production model as for roundnose grenadier. Nevertheless, owing to the migratory behaviour of the species, fisheries occurring in ICES areas Vb, VI and VII does not exploit a full population but only one life stage (pre-adults) which recruit to the area and leaves it a few years later. The situation where fish recruit and leave the fishing ground it not unique to black scabbardfish in the context of DEPFISHMAN, the same might occur for Greenland halibut in Case Study 5, and this may be the case for a number of deep-water and not deep-water stocks and fisheries worldwide. How to assess fish abundance and manage fishery in such situations is an open question. Greater forkbeardThe ICES advices since 2006 state that fisheries on greater forkbeard should be accompanied by programmes to collect data. Sufficient data may provide basis to develop an assessment. However, it does not seem appropriate to try to rely upon fishery data. Catch and effort data may not be accurate for this species for the following reasons:
As a result, assessment based upon survey data might be considered for this species. The outcome of the FISBOAT project could be used to define an assessment method. Portuguese dogfish and leafscale gulper sharkOwing to the current zero TAC only on-board observation data and survey data will be available in future years. It seems unrealistic to assess the age composition of the catch of these species as there is currently no method for age estimation of Portuguese dogfish and, although consistent with other biological knowledge and age observed for other sharks species, age estimation of leafscale gulper shark is not validated. Length distribution of the (discarded) catch should be collected. Nevertheless, is has not been observed that the length distribution reacted to exploitation for these species. Therefore, mainly abundance indices for on-board observations and surveys should be used to assess trends in abundance of deep-water sharks. Directory: lib -> exe exe -> Homework Problem Set 3 Solution I. Reading Assignment exe -> System Modeling Assessment & Roadmap wg exe -> Artemis-2011-1 decision and platform support for model‐based eVolutionary development of Embedded systems Date of preparation exe -> Date: January December 2011 Java 5 Language psm for dds (dds-java) exe -> Notes on bcd by N. Toge (Jan. 5, 2005) Instrumentation and Control General exe -> Case Study 3 Report – Black scabbardfish in ixa exe -> 1 Beneficiaries (Partner Description) exe -> Pre-requisites exe -> Suggested (Sample) Research Project Topics (Fall 2010) Download 2.38 Mb. Share with your friends:
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