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摘要
This three year field investigation consisted of three discrete experiments, examining six potential sites for rearing the European lobster (Homarus gammarus) around the Cornish coast (U.K.). Sea-based container culture (SBCC) systems were deployed, varying site, year, depth, shelter and pre-fouling, to test effects on growth and survival of juvenile H. gammarus. Site and depth were examined between May-August 2011 at two sites off the South coast. One estuarine (River Fal: RF) and one sea-based (St. Austell Bay: SA) site were assessed with containers suspended at either 2 or 8 m depth. Greatest survival was found at the SA site (56%) compared to RF (25%), with the greatest growth (specific growth rate: SGR 3%, live weight gain: LWG 0.4 g and carapace length gain: CLG 4.5 mm) also achieved at SA. Depth did not affect juvenile development. Between May and August 2012, one estuarine (Fowey: F) and two sea-based (SA and St. Mawes: SM) sites on the south coast were selected to assess the effect of site and shelter. SM showed the highest survival (93%). Growth and survival were not affected by the presence of a shelter. From August to December 2013, three sites off the north and south coasts were selected to assess the effect of site, depth, pre-fouling and feed availability. Sea-based (Port Quin Bay: PQ, Wave Hub: WH and SA) sites were assessed, with containers submerged at either 3 or 10 m above the sea bed (PQ 7-14 m, WH 42-49 m depth at chart datum). Survival did not significantly differ between sites (61-86%), but growth at the PQ site (LWG 0.7 g; carapace length gain: CLG 6.1 mm) was significantly greater than at all other sites (LWG 0.3-0.4 g; CLG 2.5-3.6 mm). Depth did not affect juvenile development. Pre-fouling reduced growth at all sites. Feed availability varied between sites with PQ showing the greatest taxonomical units. Variations between years were also shown between 2011 and 2013 at the SA site. SBCC systems show potential for culturing H. gammarus juveniles compared to hatchery controls (survival <= 46%), acting as a transition step between hatchery rearing and release for stocking purposes. The importance of site selection and between year variations is highlighted as important factors to consider for larger scale assessment of aquaculture potential. Statement of relevance: This work presents the culmination of three discrete studies between 2011 and 2013 that investigated the use of sea based container culture (SBCC) systems for rearing European lobster (H. gammarus) juveniles at various sites around South West England. This is a relatively novel field and the first study of its kind to consider sites around the South West of England and also to quantitatively assess potential feed species. The main findings of this work identify the importance of site selection, deployment and container structure. With an ever increasing demand for protein, there needs to be efforts to relieve pressure on natural fishing stocks. This study not only highlights the potential for SBCC to provide improved stock enhancement processes but also discusses the potential for aquaculture of this currently unexploited species. Juvenile culture is one of the bottlenecks for the development of lobster culture due to high unit cost of production, high mortality rates due to cannibalism within intensive culture systems and long development times, and as such we feel that this work is extremely timely and relevant. This manuscript will not only contribute to the understanding of how SBCC systems can be employed, but also adds to our understanding of the requirements of the species. Therefore, this work is of significant interest to those involved in the culture of lobsters and marine animals generally.
- 出版日期2015-11-1
