摘要:

World cultured shrimp production increased from 0.4 million metric tons (MMT) in 1990 to about 0.8 MMT in 1999, or about 25 to 30% of total shrimp supply. Increased production was well below 1.2 MMT predicted 10 years earlier. The primary reason for this shortfall was shrimp disease, which effected shrimp yields worldwide. The most serious diseases were viral, for which there are still few certain solutions. As a result of shrimp disease problems, pond culture practices changed to reduce disease incidence. These changes included: use of specific pathogen free (SPF) and specific pathogen resistant (SPR) shrimp seed; reduced or zero water exchange during pond growout; shrimp culture at inland locations away from coastal influences; use of water recycling and reuse growout systems; development of biosecure systems to prevent disease access during shrimp's entire culture cycle; development of probiotics and immunostimulants to reduce disease susceptibility; and genetic selection and improvements through closed, life-cycle culture. In addition, environmental awareness and concerns about shrimp culture sustainability became increasingly important with the informed public during the 1990s. This included concerns about habitat degradation and destruction, reduced biodiversity, and exotic shrimp introductions. Herein we review developments with these culture innovations and environmental issues that have occurred during the last 10 years.

ISSN:1064-1262    

DOI:10.1080/10641260091129215

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Estimates of the standing stock of Antarctic krill (Euphausia superba) have ranged from less than 100 million tons to over a billion tons. While considerable uncertainty is associated with these estimates, the fishery on Antarctic krill has the potential to be among the largest in the world. The harvest of Antarctic krill is currently managed by the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), part of the Antarctic Treaty system. In this review, we examine the political context and management approach of CCAMLR; we review the current understanding of natural controls on population growth of the resource; and we discuss future options for CCAMLR. We conclude that the political foundation for the CCAMLR mandate of an “ecosystem approach to management” is sound; that substantial progress has been made toward interpreting and implementing the Convention; and that environmental factors may exert a substantial influence on krill recruitment and population growth. We also note that the current fishery in the southwest Atlantic sector of the Southern Ocean (ca. 100,000 tons per year) is small compared with the precautionary limit established for this area by CCAMLR (1,500,000 tons per year), but fishing effort concentrated near colonies of land-breeding krill predators may pose a threat; that improvements to the current krill yield model are warranted; and that uncertainty regarding the character of natural variability in krill abundance and regarding the future development of the krill fishery act to obscure a strategic vision for CCAMLR. We discuss the likelihood of future scenarios and the appropriate options for CCAMLR, and we suggest a general outline for the development of a management scheme based on ecosystem process monitoring. We conclude with a comment regarding the value of a conservation ethic in the face of uncertainty.

ISSN:1064-1262    

DOI:10.1080/10641260091129224

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor