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REDFISH
Population structure, reproductive strategies and demography of redfish (genus Sebastes) in the Irminger Sea and adjacent waters (ICES V, XII AND XIV; NAFO 1)

The present internationally-developed proposal aims to increase the fragmentary and preliminary biological knowledge about commercially-exploited golden and deep sea redfish stocks (Sebastes marinus L. and S. mentella Travin) in the Irminger Sea and adjacent waters, within the frame of an agreed four-year research programme. As a multidisciplinary project, it has been designed to jointly investigate unsolved problems in the field of stock de-limitation, reproductive strategies and demography respectively, as three separate tasks. A total of 16 scientists and six technicians from the German federal research centre for fisheries (coordination, EU-Germany), Institute of Marine Research (EU-Spain), Marine Research Institute (Iceland), Institute for Marine Research (Norway) and the University of Bergen (Norway) will collaborate and contribute to the various analyses.

Objectives
Two commercially-exploited redfish species occur in the Irminger Sea and adjacent waters: golden redfish (Sebates marinus, Linnaeus 1758), and deep sea redfish (Sebastes mentella, Travin 1951), which are currently treated as three management units straddling European, Faeroes, Icelandic and Greenlandic EEZs, as well as international waters. They are defined as golden redfish and deep sea redfish on the continental slopes, and as oceanic redfish in the pelagic Irminger Sea waters. The pelagic occurrences of redfish below 500 m and the 'giants' of the Reykjanes Ridge remain unidentified. This project is divided into three work packages:
1) population structure
2) reproductive strategies
3) abundance and demography.

Work Package 1 focuses on the species and population structure and the identification of possible distinct gene pools of the redfish occurrences in the Irminger Sea and adjacent waters. The identification and delimitation of the self-sustaining stock units is the prerequisite and basis for any management action in accordance with the FAO 'Code of Conduct for Responsible Fisheries' (Food and Agriculture Organisation) and the UN Agreement on 'Straddling and Highly Migratory Fish Stocks'. Recently, the annual exploitation rates exceeded 200 000 tons although knowledge is lacking about the recruitment processes or migration patterns of different life stages. At present, there is only preliminary information available about the species and population structure for Sebastes marinus and deep-sea S. mentella inhabiting the shelves and continental slopes off Greenland, Iceland, the Faeroes and even the pelagic water column above 2 000 m depth. For larvae and juveniles, even the discrimination of species is doubtful. Preliminary information suggests the existence of various distinct gene pools but this is based on a limited material in terms of temporal coverage as well as the size groups investigated. It is therefore very important to intensify the genetic investigations before any firm conclusions can be drawn.
A variety of methods is proposed to enlighten the redfish population structure. Sub-work package 1.1 deals with the classical morphometric and meristic stock identification approach while sub-work package 1.2 is designed to identify morphometric differences from the otolith shapes and to track the recruitment by comparative analyses of the elemental contents in the central otolith region (nucleus). Sub-work package 1.3 uses a variety of molecular genetic markers such as isozymes and other proteins, DNA based methods such as microsatellites, amplified fragment length polymorphisms (AFLP), nuclear DNA and mitochondrial DNA genes, to study the population structure and the species identification.

Work Package 2 will investigate the reproductive strategies of the ovoviviparous S. marinus and S. mentella in the Irminger Sea and adjacent waters by species and stock. The task will also consider ecological consequences due to the longevity of redfish and the maternal care for their embryos. Sub-work package 2.1 aims at a description of the variation in sexual maturation in time and space. By means of histological techniques, the length at first maturation (maturity ogive) and reproductive cycles will be identified. The expected variation in reproductive processes between areas and seasons will be compared with the environmental effects and findings of the population structure analyses (from work package 1). Sub-work package 2.2 deals with the estimation of female fecundity during four different stages of the ovary development. Size and age effects on female fecundity as well as egg and larvae condition will be investigated. Precise information is expected on the amount of larvae released by the females and ecological background comparing the results with oviparous and short-lived species.

Changes in abundance, structure and productivity of the three commercially exploited redfish management units will be monitored.

Progress to Date
Due to the high diversity of the project tasks, detailed descriptions of the various sub-work packages' proceedings can be found on the project's website (www.redfish.de) in the 'project deliverables' section. This summary highlights important results obtained and outlines the consistency of the proceedings with the technical annex of the project. In general, the consortium has reported good progress in accomplishing the work tasks. In some cases, the predefined goals have even been exceeded. During the third year of the project, most of the consortium's activities were focused on completing the material and collecting data through great efforts. The former is considered finalised in all sub-work packages.

The consortium held its third project meeting in Vigo (Spain) at the Institute of Marine Research, 19-23 February 2002. The report of the meeting is available on the project's website (www.redfish.de), which is also frequently consulted for information and data exchange (1 800 visits per year), due to its wide relevance. Various sub-work package proceedings and detailed coordination were presented during the project meeting. Important achievements included the agreement and creation of databases holding all individual properties and measurements of redfish analysed across the relevant sub-work packages: the redfish survey data (www.redfish.de/project/files/) and the commercial fishery data (www.hafro.is/~steini/Frontpage_eu_32.htm). By the end of the reporting year, the individual redfish database contained data on 10 518 redfish sampled from locations all over the North Atlantic (and even the Pacific in a few cases), with varying contributions from the sub-work packages.

Results
In accordance with the technical annex, some of the sub-work packages' coordinators were able to describe their first results, or report on completed deliverables and milestones. These are all available on the website, on either the public access or consortium-restricted areas. The highlights of the various sub-work packages are also available on this site.

Classified in FISHERIES AND AQUACULTURE

Scientist responsible for the project

Mr HANS-JOACHIM RÄTZ
PALMAILLE 9
22767 Hamburg
Germany - DE

Phone: +49 49 38905169
Fax: +49 40 38905263
E-mail: hans-joachim.raetz@ish.bfa-fisch.de

References

Project ID QLRT-1999-01222
Organisation Federal Research Centre for Fisheries
Area 5.1.2
Start date 01 January 2000
Duration (months) 48
Total cost 5 799 840 €
Total EC contribution   2 864 992 €
Status Ongoing
Web address of the project   http://www.redfish.de

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