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Spatial distributions, migratory routes and overwintering behaviour of English Channel cuttlefish (Sepia officinalis) from individual electronic tracking - MF0232

Description
Global landings of cephalopods (cuttlefish, squid and octopus) have increased dramatically over the last 50 years as the importance of cephalopods to the global market has developed. The English Channel cuttlefish (Sepia officinalis) fishery is a shared resource dominated by French and U.K. fishing fleets and has become an increasingly important component of the industry. However, despite the recent increased interest and landings there exists no directed cuttlefish management: no total allowable catch is allocated and no minimum legal size is applied. The lack of management may be particularly problematic because cuttlefish are targeted both on their coastal spawning grounds, in their pre-adult stage and in offshore, deep-water sites. Exploitation of individuals from important life stages (juveniles, spawning adults) and across diverse habitats that may comprise much of their distributional range during an individual’s lifetime, identifies a need for basic information of their spatial behaviour and population structure.

The proposed research will address this knowledge gap directly by attaching electronic ‘lifetime’ archival tags by a novel method to individual juvenile and adult cuttlefish to resolve their migratory routes, overwintering areas and seasonal distribution in the English Channel, which is arguably the most important fishery area for this species. Individual cuttlefish down to 10 cm mantle length will be tagged enabling a large portion of a cuttlefish’s life to be tracked with tags that will record movement data for up to 1 year. Because the new tagging method developed by us attaches the tag to the cuttlebone itself, we will recover tags not only from individuals caught via the fishery, but following natural mortality when cuttlebones float ashore after death. Our pilot work has confirmed the feasibility of these tag retrieval methods.


The results of this research will provide the first data available on the long-term movements, habitats and distributions of cuttlefish in the English Channel. Determining migratory routes, overwintering areas, spawning site fidelity and changing seasonal distributions will contribute to assessing the spatial overlap through time of this population with fishing vessels from the UK and France. This will enable evaluation of where aggregations of cuttlefish are likely to be throughout the annual cycle and hence contribute to estimates of the likely levels of exploitation faced by different components of the population. The results will feed into potential spatial/temporal management measures required for this species, and in assessing the need to protect inshore spawning habitats, such as seagrass beds.
Objective
The aim of the proposed research is to determine the longer term movements (incl. migratory routes), behaviour and seasonal distribution patterns of common cuttlefish Sepia officinalis in the western English Channel.

The specific objectives are to:

(1) Attach long-term electronic data-logging (archival) tags to individual cuttlefish (n = 100; size classes 1 and 2) wild-caught in a key area of the fishery in the western English Channel.

(2) Promote awareness of the research to stakeholders and potential retrievers of the tags.

(3) Analyse tag data to estimate horizontal movements of Sepia over seasonal scales for identifying seasonal spatial distributions, migratory routes, overwintering areas and for assessing the potential for fidelity to spawning habitat.

(4) Identify activity patterns from tag-recorded vertical movement data to define behaviour patterns associated with particular habitats and the timing of movements in relation to environmental factors (e.g. sea temperature).

(5) Evaluate the role of movements and behaviour on population structuring of Sepia at the larger scale.

(6) Dissemination of outputs of the research to fisheries managers, fishers and policy makers.
Project Documents
• EVID4 - Final project report : MF0232 Evid 4 Evidence Project Final Report   (314k)
• EXE - Executive Summary : MF0232 Executive Summary   (220k)
• TPS - Two Page Summary : MF0232 two page summary Final   (156k)
Time-Scale and Cost
From: 2012

To: 2013

Cost: £94,852
Contractor / Funded Organisations
Marine Biological Association
Keywords
Marine              
Shellfish Water              
Fields of Study
Marine Fisheries