Abstract:本文根据1993年7—8月和1994年8月西北太平洋柔龟渔场调查资料。分析柔鱼渔场与水温因子的关系。归纳出六种不同的海况类型(暖水团型，表温分布密集型，表温分布舌状型，黑潮前峰区型，黑潮型和亲潮型)。调查表明8月份日渔获量(CPUE，kg／天)与0—100m(△T1，℃)和0—50m(△T2，℃)的水温差成正比，关系式分别为CPUE=-1213 314△T1和CPUE=-880 365△T2。柔龟渔场的形成主要取决于表层等温线密集、暖水团存在以及温跃层的形式。这为发展西北太平洋柔龟钓生产和寻找渔场提供科学的决策依据。

Abstract:In this paper the results of the fishing improvement test for the octopus trawlnet operated by Chinese fishing vessels in the West Sahara waters were conducted. The results showed that it is possible to improve net per formance and make it more adaptable to the behaviour of octopus by modifying some dimensions and parameters of the net.The improvement design included expanding main dimension of the net, such as net length, net mouth circumference, lengths of both headrope and groundrope, increasing the weight of the groundrope, and changing the length and distribution of three tickler chains in order to improve the property of the spreading, bottom-touching stability, fish-guiding of the net and disturbance of the tickler chains.The new-designed net has been operated in the Waters from July 17th to December llth, l993. Both the production and output value all incereased more than 17%.The results of this test indicated some important considerations, to which more attention should be paid in further improving trawlnet performance.

Abstract:Two methods for rearing fingerling of large-mouth black bass, Mcropterus salmoides with natural prey and supplementing natural prey with feed rnixture were described in this paper. The larvae have significant selectivity to zooplankton in its different developmental stages. The finerling with yolk and oil droplet preferred to feed on rotifera and nauplius as it was 5. 4-6. 8mm in length. It turned to feed on cladocera and copepodid as it grew to 8.1 -20. 0mm. And it began to feed on cladocera and copepoda as it was 21. 3- 30.3mm in length. In that period, the larvae also fed on feed mixture. The proportion of feed mixture in the digestive tract of the fish increased with the growth in body length- Dialy increase in boby length and body weight was 1. 23mm and 20. 35mg respectively after 20 days of rearing with natural prey while they were 1. 43mm and 24. 69mg respectively in the group fed with supplementing natural prey with feed mixture. As for growth performance, the latter is higher than the former. It showed that there is singificant difference between these two rearing practices, by t-test (t=3.19>t0.05 (2. 101). The results implied that feed mixture can be supplementary with natural prey,and it will improve the survival of the fingerling and enhance the growth significantly.

Abstract:RNA and DNA concentration of grass carp, silver carp, big head carp and blunt snout bream at different developmental stages (fry, one-year and two-year old) were measured. Changes of RNA/DNA ratio accorded with the tested fish growth. Ther fore,RNA/DNA ratio could be as an indicator for evaluating-the fish growth at fingerling stage.

Abstract:Blood of livestock is rich in crude protein. Extrusion processing may increase the protein digestibility (PD). Blood is much more difficult than starch ingredient to extrude, which determines the sl)ecial design of the extruder. Based on the theoritical analysis and experimental results, the special design for structure and size of the extrusion system, which helps technicians to solve the technique and technological problems, is reviewed in this paper.

Abstract:拖网渔具必须适应渔场和捕捞对象的特征，这对提高渔获效果是十分重要的。本文对几内亚渔场所使用的48．78×56．64m六片式拖网的规格和主要性能参数作了具体分析，并对网衣配置、装配工艺和几个部位的工艺性处理作了详细的说明。通过生产实践和与其它几种网型的比较，证明了该种类型的拖网的优越性，以期对今后的渔业生产有所帮助。