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More than 4000 settled lobster juveniles produced in Galicia
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In all three participating AquaReg regions, the European clawed lobster is a highly prized and gastronomically appreciated marine resource. However, the reported lobster landings have declined during the last decades, perhaps most dramatically in Galicia.
The AquaReg lobster sub-project puts focus on this matter and three European regions join forces to try to find solutions that can help on this matter.
The AquaReg lobster sub-project is a regional cooperation with the aim to produce lobster juveniles at a practical |
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Vieving a mother lobster with juveniles |
and economical cost that is acceptable. In the autumn 2004 it was extremely difficult even to obtain egg-bearing females in Galicia as broodstock for this project.
Releases of artificially raised lobster juveniles provide an alternative action that could contribute to re-establishment or enhancement of the regional lobster stocks. However, one of the key problems in this context is the lack of an effective methodology for production of juveniles. The purpose of the AquaReg project "A regional development strategy for stock enhancement of clawed lobsters" is to exchange knowledge and transfer technology between the regions to develop an improved methodology for producing viable lobsters juveniles for release into the sea.
Over the last year, there has been an active knowledge and technology transfer between the Martin Ryan Institute in Ireland, the Norwegian Institute for Nature Research in Norway and IGaFA in Spain. This work has involved a workshop, practical demonstrations and intensive assistance in the design, construction and operation of a production unit for settled lobster juveniles at IGaFA, Illa de Arousa, Galicia. On basis of methods developed at the University of Maine in the US by Dr. Brian Beal, the lobster hatchery has been constructed in a transportable container, thus being the first mobile lobster hatchery ever been built. Under optimal conditions, the hatchery can have a capacity for producing more than 10,000 settled lobster juveniles per year.
When lobster eggs hatch, the larvae that are released are free-swimming and they drift with the seawater currents as do other planctonic organisms. During this free-swimming period of their life cycle, they molt or shed their shells three times before they metamorphose and change into juvenile lobsters that settle on the seabed. This spring almost 4,400 of such settled juveniles were produced for training purposes, and for studies investigating optimization of on-growing methodology. After preliminary trials, the survival from hatching to settlement was very high, with an exceptional maximum survival at more than 90%.
Settled European lobsters are only 1.5 to 2 cm long, and are therefore extremely vulnerable to predation if they are released directly into the sea. For this reason, it is important to rear the lobsters until they reach a length of 4-5 cm before they are released to increase their chances of survival.
Currently, trials involving a variety of ways of rearing lobster juveniles are ongoing, and preliminary results indicate that survival and growth in the initial phases of the most promising on-growing methods is good. These trials are, however, in an early phase and require further refinement and optimization based on results being obtained during this summer will take place during the coming year. It is hoped that an additional outcome to this project will be a greater appreciation for the need to effectively manage lobster stocks and thereby improve landings.
For more information about this project, see www.aquareg.com.
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