Proceedings

"Stock Enhancement and Sea Ranching", ISBN 0 85238 246 4, January 1999
Eds: B.R. Howell (UK), E. Moksness (Norway) and T. Svåsand (Norway)
Publisher : Fishing News Books, Blackwell Science ltd.Osney Mead, Oxford OX2 0EL,United Kingdom.Tel: +44 1865 206206;Fax: +44 1865 206026; E-mail: fnb@blacksci.co.uk; Internet: Currently out of print, but available here

Background

Most populations of marine animals of commercial and recreational value to mankind appear to be limited by natural variations in the supply of juveniles. Critical habitat for spawning and early life stages for many marine and coastal species has been degraded or lost as a result of pollution, coastal development and other human activities. As a result, the carrying capacity of many marine habitats for juvenile and adults of many marine species is seldom reached. In addition, recruitment overfishing has prevented many populations from replenishing themselves quickly. Together, these phenomena produce circumstances where marine habitats do not support as many fish as they could. Tighter controls on fishing are only part of the answer to sustainable, increased production from marine habitats. The effects of natural recruitment limitation can only be overcome by stock enhancement, i.e. the release of cultured juveniles to augment natural populations.

Stock enhancement and sea ranching has been practiced for decades for a wide variety of marine fish and invertebrate species in Japan, and for salmonids. The lessons from these experiences, and the recent advent of a variety of techniques, have encouraged fisheries scientists and managers worldwide to consider the use of stock enhancement to increase the productivity of existing fisheries, to create new fisheries, and to restore those that are no longer viable.

Apart from the programes in Japan, and those on salmonids, vigorous projects are now underway on cod in Norway, striped mullet in Hawaii, red drum in Texas, white seabass in California, scallops in New Zealand, shrimp in China and sturgeons in the Caspian Sea, to mention just a few. Many more projects are on the drawing boards.

Stock enhancement of marine species and salmonids is not straight-forward, however, largely because of their complex life cycles and the potential for wide dispersal from release sites. In view of these problems, the increased interest in stock enhancement of marine fisheries, and the potential of hatchery release as a management tool, it is time for a comprehensive appraisal of the benefits and effects of stock enhancement and sea ranching. Questions abound: Are hatchery-reared fry fit for release in the wild? How should fry be released to maximise their survival? How can the contribution of released fry to wild stocks be measured? Is stock enhancement cost-effective? Do hatchery releases affect the genetic structure of wild conspecifics? If so, how can this be minimised? Does enhancement increase the risk of transmitting diseases to wild stocks? Will enhancement result in increased competitive and predatory interactions with other species? Who will have rights to exploit enhanced stocks?

Many of these issues have been on the agendas of major fisheries and aquaculture conferences in recent years. However, the presentation of information, and debate, at these conferences has been limited by the time available. The First International Symposium on Stock Enhancement and Sea Ranching has been organised to provide a major forum dedicated to discussion of stock enhancement by scientists and managers from around the world. The Symposium will enable participants to learn from the collective global experience and to develop rigorous, responsible approaches to assessing the merits of stock enhancement. Future symposia will be reconvened every four years to keep scientists and managers abreast of developments in the field.

Objective

The main objective is to bring scientists and managers together to exchange knowledge about the processes and consequences of stock enhancement and sea ranching, and to identify the most important priorities for future research.

The organisers invite papers on stock enhancement and sea-ranching that contribute to knowledge of the application, cost-benefit and ecological impact of these fisheries management measures. Contributions on marine fish, crustacea and molluscs, and salmonids are welcome. Papers should make a contribution in one of the following areas:

• the fitness of hatchery-reared juveniles for life in the wild,
• strategies for tagging and releasing juveniles into the wild and measuring their contribution to fisheries,
• ecological and genetic interaction between wild and enhanced populations of fish, crustacea and molluscs, including introduction and transplantation of non-native species or genetically modified organism (GMO),
• risks of introducing diseases and parasites,
• method of assessment, monitoring, and management of populations such as density effect and carrying capacity,
• economic viability of stocking programes,
• the decision-making process, i.e. to use, or not to use, enhancement as a management tool,
• right of access issues: who has the right to harvest an enhanced resource? what problems are likely to occur?
• organisation models.

Organising Comittee

Convener:

E. Moksness (Norway)

International Scientific Committee:

Chairman: B.R. Howell (UK)

Local Organising Committee:

Chairman : J Borthen (Norway)

Key note speakers

• Introductory lecture Alain Laurec (EC): Can the conditions for a successful enhancement or sea ranching be defined.
  

Session 1: Theoretical basis for stock enhancement

• Peter J. Doherty (Australia): Recruitment limitation as the theoretical basis for stock enhancement
  
• Eskild Kirkegaard (Denmark): Stock enhancement and sea ranching as an alternative to traditional management
  
• I-Chiu Liao (Taiwan): How can stock enhancement and sea ranching help sustain and increase coastal fisheries

Session 2: Methods/factors influencing success

• Kenneth M. Leber (USA): Experimental approach to stock enhancement in Hawaii
  
• Katsumi Tsukamoto* and Reiji Masuda (Japan): Cultured fish behaviour and quality

Session 3: Measuring success

• Shuichi Kitada (Japan): Effectiveness of Japan's stock enhancement programs: Current perspectives

Session 4: Impacts of stock enhancement

• Tom F. Cross (Ireland): Genetic considerations
  
• Jarl Giske* and Anne Gro Vea Salvanes (Norway): Carrying capacities and ecological considerations
  

Session 5: Management of enhanced stocks

• Abraham Hallenstvedt (Norway): Social, economic and access issus
  
• William Howarth and Cristina Lería* (FAO): Legal issues relating to stock enhancement and ocean ranching
  
• Koji Imamura (Japan): Promotion of stock enhancement and sea ranching program in Japan - Current status and issues

Session 6: Case studies

• Colin A. Bannister*, J. T. Addison and M. C. Bell (England): The European clawed lobster : hatchery-reared juveniles can survive in the wild, but can they contribute significantly to ranching, enhancement and fisheries management ?
  
• Devin M. Bartley (FAO): World-wide perspective
  
• Johann Bell (Solomon Islands): Restocking of giant clams in the Indo-Pacific
  
• Jean-Claude Dao (France): Scallop seabed cultivation in Europe
  
• Tor G. Heggberget (Norway): Sea ranching of Atlantic salmon in Norway - limitations and possibillities
  
• Peter C. Rothlisberg*, N. Preston, N. Loneragan, D. Die, I. Poiner (Australia): Approaches to reseeding penaeid prawns
  
• Terje Svåsand* Rolf Engelsen, Arne Kolbeinshavn, Tore S Kristiansen, Mariann Nødtvedt, Torstein Pedersen, Anne Gro Vea Salvanes (Norway): Cod enhancement in Norway - Evaluation of present results and further prospects