摘要:

A great deal of research has been conducted during the last 3 decades on the essential fatty acid (EFA) requirements of fish. It has been clearly demonstrated that warmwater fishes, such as carp and eels, require both n‐6 and n‐3 fatty acids, whereas cold‐water fishes, like salmonids, require only n‐3 fatty acids. Considering seawater fish as a group, we find that among the n‐3 fatty acids, the effect of linolenic acid (LNA) as an EFA is lower compared with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Larval marine fish exhibit a distinct need for DHA. The EFA requirement of other aquatic animals, such as shrimp and mollusca, also have been investigated. There exists a wide variation in the EFA requirement patterns of aquatic animals.

ISSN:1064-1262    

DOI:10.1080/10641269709388592

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

This paper reviews the international literature on the natural enemies ofDreissenaspp. and discusses the biology and ecology of organisms known to be involved in their predation (176 species), parasitism (34 species), and competitive exclusion (10 species). Research on natural enemies, both in Europe and North America, has focused on predators, particularly birds (36 species) and fish (15 and 38 species eating veligers and attached mussels, respectively). Other field‐documented predation includes consumption of pelagic larvae by copepods and coelenterates, and consumption of attached mussels by leeches, crabs, crayfish, and rodents. Cannibalism of veligers by adult zebra mussels has also been reported. Ciliates and trematodes are the most commonly reported obligate parasites, with occasional records of suspected bacterial or ascetosporan infection. Mites, nematodes, leeches, chironomids, and oligochaetes have been observed to be associated symbiotically within the mantle cavity, but with few to no adverse effects. Organisms capable of competitively displacing zebra mussels from hard substrates include sponges, amphipods, algae, bryozoans, hydrozoan coelenterates, and other bivalve species (including interspecific competition amongDreissenaspp.).

ISSN:1064-1262    

DOI:10.1080/10641269709388593

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor