Optimising commerical practices and developing aquaculture techniques for the Norway lobster (Nephrops norvegicus) fishery
Cowing, Daniel Mark
Thesis or dissertation
- © 2017 Daniel Mark Cowing. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
The Nephrops norvegicus (referred to as Nephrops) fishery is regarded as one of the most important fisheries around the UK, yet data suggest that landings are declining. The role of hatcheries for other crustacean species has proved useful for stock enhancement and aquaculture. Nephrops larviculture has been relatively unsuccessful, with low survival to post larval stages. This thesis comprises four studies aimed at developing key stages that are important for optimising fishing related practices and the development of aquaculture for this species. In chapter 3, the social behaviour of adult Nephrops is examined in conjunction with physiological parameters. The findings indicate that the behavioural interactions have a physiological cost that is associated with the sex and size of the individual and the opponent. The findings are useful for developing fishing practices and broodstock holding and highlight the complexity of correlating physiological parameters with social stress. In chapter 4, a method for sedating and anaesthetising Norway lobster is investigated and successfully identified. Key behaviours are related to sedation stages as well as to several tested dosages. These techniques could be used to lower stress in Norway lobster during transport and handling. In chapter 5, several diets and feeding frequencies are examined for their potential in increasing larval survival and growth. The highest survival and growth were found in the enriched Artemia diets, with a continuous feeding frequency. Larvae fed on wild zooplankton had lower survival and delayed growth, especially for stage 1 larvae. The addition of probiotics yielded promising results in terms of better survival and less variation when compared to an enriched Artemia diet alone. Survival of larvae was increased to ~40% which is an improvement on previous findings and suggests further investigation for optimising larviculture techniques. In chapter 6, the behaviour of post larvae around an adult burrow and an alternative habitat is investigated. The post larvae showed a preference for entering the burrow when it was unoccupied, but would show vigilant behaviour when it was occupied. The post larvae would also find shelter in alternative habitats such as cobbles, which could be a promising application in future release protocols for this species. The results from the thesis demonstrate that Nephrops aquaculture for stock enhancement can currently take place, and that techniques for holding and transporting broodstock can be improved.
- School of Environmental Sciences, The University of Hull
- Johnson, Magnus
- Qualification level
- Qualification name
- 6 MB