选择抗生素类渔用药物的注意事项(中)

药物散剂。在药物中添加一定比例的乳糖、酵母粉等成为药物散剂。

选择抗生素类渔用药物的注意事项(上)

投药的标准量 1.根据水产动物重量计算标准用药量虽然在水产动物养殖的实际生产中，计算标准用药量有各种方法，但是，只有根据水产动物的体重计算标准用药量，才是正确的方法。这是因为在现代水产动物养殖生产中，为了获得较高的经济效益，需要经常对养殖的水产动物按规格进行选择，将规格相同的个体饲养在一起，因此，即使对于实施群体饲养的水产动物，其个体间的摄食量也不会有太大的差异。

中国近海鱼类生活史型与生态学参数地理变异

根据1985—1986年东海北部近海调查材料及其它有关文献,对43种鱼计74个种群或群体的生活史选择型及其生态学参数进行了比较研究。结果表明,分布于我国近海的主要鱼类大多偏于r选择型。此外,对r—K选择鱼种的资源特征反其对捕捞的反应作了阐述。各鱼种的种群生态学参数在种间和空间分布上均表现出地理变异。

中国海洋渔业资源(一)

Ⅰ.渤、黄、东、南诸海渔业生物群落生态特征 我国海域系一典型陆缘海,由此决定了我国海洋渔业资源数量有限和渔业规模不可能太大的格局。其渔业生物群落的存在形式是:以渤海和黄海区的黄海槽我国一侧斜坡。

论南海高度洄游鱼类资源合作保护机制

南海有着丰富的渔业资源,分布着大量的高度洄游性鱼类,但随着沿海国捕鱼量的增加和环境的破坏,南海渔业资源正逐年减少,南海各沿海国进行合作保护南海高度洄游性鱼类不仅是经济全球化和区域经济一体化的要求,也是维护我国主权的表现,我国有必要重视南海高度洄游性鱼类资源的合作开发与保护。文章结合南海高度洄游鱼类合作保护的必要性和现实情况,提出了缔结多边条约、建立合作组织、实施休渔制度等措施以保护南海高度洄游性鱼类资源的建议。

马蹄泉水库渔业生产配套技术

水库面积30亩,实行二配套二结合的技术路线,采取以牧草为基础的综合利用方式,1989—1991年共生产鱼苗8830万尾,夏花108万尾,1龄鱼种11.96万尾,商品鱼15206.5kg,盈利9.05万元。年亩均盈利1005.33元,投入产出比1:2.93。

渤海海洋资源的开发与持续利用

渤海是我国一个半封闭的内海,海域面积7.7×104km2,具有丰富的海洋生物资源、海洋油气资源、海盐资源、滩涂资源、港口与滨海旅游资源等。随着对渤海海洋资源的开发,已形成了海洋渔业、海洋油气开采业、海洋运输业、滨海旅游、沿海造船和海盐业等海洋经济产业部门。通过对渤海海洋资源评估、对海洋资源开发及海洋经济增长、海洋产业部门结构特征以及当前渤海存在的海洋环境污染等问题进行分析研究,并应用层次分析法(AHP)对渤海海洋资源开发利用提出了重点与发展方向,明确了环渤海地区的海洋经济是以利用资源为主的资源型经济。由此提出了渤海海洋资源持续利用的对策。

Species composition and diversity of pelagic fishes based on a longline fishery catch in the North Pacific Ocean

Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collected by an onboard scientific observer during a commercial longline fishing trip.The species richness and Shannon-Wiener diversity index of fish assemblages in the northern area were slightly higher than those in the southern area,although these differences were not significant(t test,P.0.05).Non-parametric multidimensional scaling and analysis of similarities indicated that there were significant differences in fish assemblages between the two areas(P,0.01).

Significant Effects of Fishing Gear Selectivity on Fish Life History

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

Are the fish of the upper and lower Mekong interconnected?

The Mekong supports one of the richest inland fisheries in the world, with many of the fish migrating long distance to spawn. Little is known about the fisheries and migration strategies of the Upper Mekong whilst it is supposed that many fish species move between the Lower and Upper Mekong. Most likely, natural fish migration in the river has been altered by dam construction across the mainstream of the Upper Mekong. In this paper, the interconnectivity of fish species between different sections of the Mekong and negative impacts of dams on migratory fish are studied. Of the 162 fish species in the Upper Mekong and the 869 species in the Lower Mekong, 61 species are common. Results show that there is no significant difference at order level between the UM and LM. Similarity coefficients are used to evaluate interconnectivity at species, genus and family levels among four different sections of the Upper Mekong with each other and with the Lower Mekong as a whole. The highest similarity is found between the middle and lower reach of the Upper Mekong at species and genus levels and the middle and upper reach at family level. Of the eight cascade dams, Mengsong Dam in planning is considered as the biggest threat to migratory fish from the Lower Mekong and should be particularly concerned.

Variation in the distribution of wintering anchovy Engraulis japonicus and its relationship with water temperature in the central and southern Yellow Sea

In the present study,we investigated a shift in the spatial distribution of wintering anchovy(Engraulis japonicus)and its relationship with water temperature,using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea,during 2000–2015.Our results indicate that the latitudinal distribution of wintering anchovy varied between years,but there was no consistent pattern in the direction of change(north or south).Wintering anchovy did not move northward with increasing water temperature.However,the latitudinal distribution of wintering anchovy correlated well with 10°C and 11°C isotherms.The results of both a one-step and a two-step generalized additive model indicated that water temperature was associated with both presence and biomass of wintering anchovy.This paper is the fi rst to systematically examine the relationship between anchovy distribution and water temperature using a variety of techniques.All the fi ndings confi rm the impact of water temperature on wintering anchovy distribution,which has important implications for the continued management of the anchovy resource and the enhancement of marine fi shery resources in the Yellow Sea,especially as the climate changes.However water temperature only partly explains the species distribution of anchovy,and stock characteristics also aff ect fi shery distribution.Therefore,other factors should be considered in future research.

Length-weight relationships for six freshwater fish species in Iran

The aim of this study is to report the length-weight relationship parameters （a and b） for some economically important fish species from Iranian freshwaters. The length-weight relationships （LWR） are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR （W=aL^b） vary between 2.985 and 3.543. The LWR with high correlation coefficient （r^2） is significant for all the species. These parameters axe of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.

Fishery Biology of Jumbo Flying Squid Dosidicus gigas off Costa Rica Dome

The jumbo flying squid(Dosidicus gigas) population was surveyed with the help of Chinese squid jigging vessels off the Costa Rica Dome(4°–11°N, 90°–100°W) in 2009 and 2010. The daily catch of D. gigas in the two survey cruises ranged from 0 to 5.5 t and was mostly obtained from the areas bounded by 6°–9°N and 91°–94°W and by 6°30′–7°30′N and 96°–97°W. The sea surface temperature in the areas yielding the most catch ranged from 27.5 to 29℃. The sex ratio of the total catch was 3.75:1(female: male). The mantle length of the squid ranged from 211 to 355 mm(male) and from 204 to 429 mm(female) with an average of 297.9 and 306.7 mm, respectively. In the relationship of the mantle length(mm) and body weight(g) of the squid, there was no significant difference between sexes. The female and male were at a similar maturity, and most individuals are maturing or have matured with a few females being spent. The size(mantle length) and age at the first sexual maturity were 297 mm and 195 d in females, and less than 211 mm and 130 d in males, respectively. Most of the sampled stomachs(70.6%) had no food remains. The major preys of the squids were fish, cephalopods and crustaceans, with the most abundant Myctophum orientale and D. gigas. The preys in more than 65% of the non-empty sampled stomachs evidenced the cannibalism of D. gigas. The results improved current understanding of the fishery biology of D. gigas off the Costa Rica Dome, which may facilitate the assessment and management of relative fishery resources.

Some Fishery Biology of Molluscivorous Catfish, Heficophagus leptorhynchus in Thailand

The molluscivorous catfish, Helicophagus leptorhynchus is an economic fish in Thailand, but the fish is poorly know. This paper is a review of some biology support data for aquaculture and fisheries. The fish distributed in Mekong-Chaophraya Basin. The spawners migrate to upstream in early flood season for spawning. After hatching, the fish larva migrating in downstream and the juvenile fish move in deep pool of Mekong Basin on dry season. Adult fish live in downstream and large tributary. The fish is omnivorous and bottom feeder. Spawning season of the fish is May-July. Gillnetting and beach seine fisheries are main the catfish＇s fisheries in Thailand and the catfish＇s fisheries season in Mekong River began on January-July.

排污对长江口夏季渔业水环境影响

上海市工业废水和生活污水排入长江口水域,污染了长江口水环境。本文根据1990年8月长江口区现场观测部分资料,介绍长江口夏季水体pH值、溶解氧、营养盐和部分微量金属在不同区域的分布情况。在此基础上,分析上海市排污对长江口渔业水环境影响的主要原因。

九龙江北溪供水桥闸建设过鱼设施必要性分析

该文根据九龙江北溪供水桥闸建设前和近年的渔类资源调查情况,对比分析九龙江受桥闸影响河段建闸前后鱼类资源分布特点,探讨北溪供水桥闸建设运行对九龙江鱼类资源的影响。分析表明,北溪供水桥闸建设运行后,九龙江受桥闸影响河段鱼类种类和分布范围均明显减小。北溪供水桥闸建设过鱼设施对保护九龙江河口的鱼类资源及水生态平衡具有重要意义,建议在北溪供水桥闸下游南北港建设过鱼设施,恢复鱼、蟹的洄游通道。