Aquaculture Vol. 164 (1-4) pp. 3-21
Recent developments in penaeid broodstock and seed production technologies: improving the outlook for superior captive stocks

Craig L. Browdy
Waddell Mariculture Center, POB 809, , Bluffton, SC 29910, USA
Abstract:    Pond culture of marine shrimp currently accounts for about 30% of world supply and production continues to expand. The future success of shrimp farming will depend upon increasing supplies of healthy, high quality seed for stocking ponds. In many areas, fry are still collected from the wild for stocking into ponds. To stabilize seed supplies and expand to new areas, hatchery production technologies have improved slowly over the past 20 years. Challenges associated with disease control and reducing reliance on natural feeds are being met through research efforts in the private and public sectors. Improved hygiene and biosecurity, development of probiotics and immunostimulants and improvement of artificial feeds promise better postlarval fitness while reducing cost and improving reliability of production. However, much of this production continues to rely on nauplii derived from wild gravid spawners collected at sea. Although techniques for captive maturation and spawning have been well defined, serious gaps remain in the basic understanding of the hormonal control of reproduction, the process of vitellogenesis in penaeid shrimp and the mechanical and physiological processes involved in fertilization. Presently, in areas with readily available indigenous stocks of species of choice, there is a generally accepted perception among hatchery managers and growers that performance of nauplii and postlarvae derived from wild matured spawners is superior to captive matured or pond reared animals. As we approach the 21st century, wild stocks are facing increasing pressure and shrimp farming continues to expand into new areas, away from traditional sources of wild seed. New viral disease epidemics continue to arise and spread quickly across entire regions, significantly impacting industry viability. Research and development efforts aimed at closing the life cycle of several commercially important species are underway. While significant limitations remain, encouraging results illustrating the potential for disease control, disease resistance and improved growth have been reported. The development of healthy, genetically improved shrimp stocks represents a tremendous economic opportunity while potentially improving the outlook for long term industry sustainability. The present paper is a review of recent developments in penaeid broodstock and seed production technologies focusing on current limitations while defining the significant potential offered by emerging developments. © 1998 Elsevier Science B.V. All rights reserved.

Aquaculture Vol. 164 (1-4) pp. 23-47
Penaeid genetics and biotechnology

^a J.A.H. Benzie
^a , Australian Institute of Marine Science and Cooperative Research Centre for Aquaculture, P.M.B. 3, , Townsville, M.C. QLD 4810, Australia
Abstract:    The application of biotechnology to penaeid prawn aquaculture is increasing in importance. Early doubts that such approaches were unnecessary, given the crude state of development of the prawn aquaculture industry, have been replaced by the recognition that sophisticated molecular approaches will be required to tackle key problems of disease recognition and control, and to achieve higher production through the development of domesticated strains. Progress in penaeid genetic and biotechnological research has been slow because of a lack of knowledge on fundamental aspects of their biology. However, data is beginning to emerge from research projects started in the last decade, and is likely to increase rapidly in the next 10 years. Highly variable markers have been developed that allow the genetic variation in prawn stocks to be assessed, even in highly inbred cultured lines. The extent to which growth rate is under genetic control has now been assessed in some species using rigorous experimental designs to estimate heritabilities. Highly sensitive techniques that allow the isolation and characterisation of very small quantities of peptides are being used to investigate the endocrine control of reproduction, and work has begun on the isolation and characterisation of genes that play an important role in growth and reproduction. Greater attention is being paid to developing cell lines for prawns, and to the development of molecular probes for the identification of pathogens. These tools will provide a basis for a more detailed description of the penaeid prawn genome, for understanding disease resistance, and for developing effective control of reproduction and the development of disease free or disease resistant domesticated lines. © 1998 Elsevier Science B.V. All rights reserved.