The velvet swimming crab fishery is a relatively recent development in Ireland and the UK. The collapse of the traditional fishery in the Mediterranean in the 1980’s enabled this previous pest species to become a commercially significant sector in Northern Ireland. Now the second most important commercial fishery species in Northern Ireland, recent declines in catch have caused concern among local fishermen and industry. Limited information currently exists on current velvet crab populations and trends in fishery catch in Northern Ireland. To provide initial baseline information, studies of fishery catch detailed size discrepancies between Strangford Lough and the Irish Sea. Larger, heavier crabs were consistently landed in Strangford Lough. Berried crabs were mostly found in winter and spring, which is also the peak fishery season. Histological techniques were employed to adapt a newly published method to directly determine age in crustaceans. These studies have paved the way for future research in this area, suggesting that decalcifying eyestalks is an ineffective approach in preparing eyestalk sections, and recommends alternative methods. Known to be a species vulnerable to overfishing and sensitive to the stress of capture and transport, current measures made by fishermen to alleviate stress during capture were found to be ineffective. Crabs kept on a flow through system showed reduced signs of stress. Handling was found to cause a stress response in berried females, and it is suggested that handling of these animals is reduced as much as possible. Reducing stress and maximising survival of berried females will greatly enhance recruitment to populations. Overall, this investigation aimed to provide baseline information on velvet crab fishery catch and ensure sustainable practice in Northern Ireland. This study presents results which can be used to develop management policies and inform fisheries elsewhere.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:727396 |
| Date | January 2017 |
| Creators | Hinchliff, Laura |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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