"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:; Internet: Currently out of print, but available here



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.



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:

Organising Comittee


E. Moksness (Norway)

International Scientific Committee:

Chairman: B.R. Howell (UK)

D.M. Bartley (FAO)
Y. Harache (France)
S. Kitada (Japan)
J. Bell (Solomons Island)
T.Hecht (South Africa)
K.M. Leber (USA)
H. Lee Blankenship (USA)
J.Holt (USA)
P.C. Rothlisberg (Australia)
L.P Hansen (Norway)
M.Kaeriyama (Japan)
J. Støttrup (Denmark)
A. Hallenstvedt (Norway)
H. Kanno (Japan)
T. Svåsand (Norway)

Local Organising Committee:

Chairman : J Borthen (Norway)

R. Helljesen (Norway)
M. Nødtvedt (Norway)
T. Svåsand (Norway)


Key note speakers

Session 1: Theoretical basis for stock enhancement

Session 2: Methods/factors influencing success

Session 3: Measuring success

Session 4: Impacts of stock enhancement

Session 5: Management of enhanced stocks

Session 6: Case studies