三峡库区香溪河支流放流滤食性鱼类后理化特征的比较研究

从2010年4月至2012年12月对香溪河支流7批次放流滤食性鱼类苗种1 468万尾,对放流前与放流后的水域理化因子特征进行常规监测.结果显示,放流滤食性鱼种后总氮(TN)、氨氮(NH4-N)、亚硝酸盐氮(NO2-N)、硝酸盐氮(NO3-N)、总磷(TP)、正磷酸盐磷(PO4-P)、化学耗氧量(COD)、叶绿素a要明显低于放流前,投放苗种前平均值分别为3.10 mg/L、0.421 mg/L、0.048 mg/L、2.869 mg/L、0.549 mg/L、0.299 mg/L、16.563 mg/L、26.447 mg/m3;放流鱼种后平均值分别为2.20 mg/L、0.065 mg/L、0.022 mg/L、1.643 mg/L、0.495 mg/L、0.155 mg/L、10.465 mg/L、6.608 mg/m3.放流前支流营养化TLI为67.0、放流后为56.4,香溪河支流水域呈轻度富营养化(TLI＞53).为生态修复调控水华发生建议香溪河支流水域每年放流滤食性鱼类苗种.     

Dams in the Amazon: The importance of maintaining free-flowing tributaries for fish reproduction

1. Free-flowing tributaries are important for the maintenance of fish diversity in dammed systems. In relation to the reproduction of fish species, the role of a free-flowing tributary was evaluated and compared with that of a dammed tributary downstream of large dams in the Madeira River, one of the main tributaries of the Amazon River.
2. Two hypotheses were tested: (i) the densities of the ichthyoplankton differ between the dammed and the free-flowing tributaries; and (ii) the free-flowing tributary contributes a greater diversity of fish larvae species to the assemblage structure of the main stem than the dammed tributary.
3. Fish eggs and larvae were sampled at five sites: one in each tributary (Jamari – dammed – and Machado – free-flowing) and three in the main stem (Madeira River), upstream and downstream from the mouth of each tributary.
4. Fitted Bayesian models showed that the densities both of eggs and larvae were more than twice as high in the free-flowing tributary than in the dammed tributary. The results also indicated that the free-flowing tributary makes a major contribution to the fish assemblage structure of the Madeira River, whereas the dammed tributary does not have a significant influence on the main stem assemblage structure.
5. The results demonstrate the importance of conservation and maintenance not only of the Machado River but also of other free-flowing tributaries in dammed basins, especially those basins with high biodiversity, such as the Amazon. Moreover, this study helps inform the decision-making process regarding the location of new dams, which is critical in fish diversity conservation.

     

几种近海底层鱼类和中上层鱼类隐蔽伪装色的比较

为了探明近海不同生态类型鱼类隐蔽伪装色的差异,研究了6种中上层鱼类和5种底层鱼类的隐蔽伪装色,结果表明:无论近海中上层鱼类(包括大甲鲹Megalaspis cordyla、斑■Hemiramphus far、五条■Seriola quinqueradiata、竹■鱼Trachurus japonicus、蓝圆鲹Decapterus maruadsi、蓝点马鲛Scomberomorus niphonius)还是近海底层鱼类(海鳗Muraenesox cinereus、斑尾复虾虎鱼Synechogobius ommaturus、带鱼Trichiurus japonicus、单角革鲀Aluterus monoceros、龙头鱼Harpadon nehereus),黑色素细胞和黄色素细胞均为背部多腹部少,差异显著;相比近海底层鱼类,近海中上层鱼类背腹部体色差异更加明显,中上层鱼类黑色素细胞和黄色素细胞差异更大;虹彩细胞在背腹部皮肤中都存在,而近海底层鱼类的腹部主要为虹彩细胞;红色素细胞在近海底层鱼类中很少存在,但在中上层鱼类中较多。上述结果显示,鱼类背部体色的深浅主要与皮肤中黑色素细胞和黄色素细胞的数量有关,腹部体色的形成主要与虹彩细胞的多少有关。     

三峡库区鱼类环境和污染状况

三峡库区的自然环境适合于多种鱼类的生长,库区水质表现一定的季节变化,水体中大肠杆菌和铜等超标;鱼体内主要污染物为Ｃｄ,Ｃｒ,Ａｓ等,但未超标,食用品质较好;鱼样外周血红细胞微 ０．８２‰－４．２８‰,表明水质对鱼体细胞具诱变作用。     

Relationships between macro‐epibenthic communities and fish on the shelf grounds of the western Mediterranean

• 1. The present study characterizes the macro‐epibenthic assemblages, and the relationships between demersal species and benthic habitats on the shelf trawl fishing grounds off the Balearic Islands (western Mediterranean).
• 2. The data used were collected during experimental bottom trawl surveys from 2002 to 2005. A total of 157 samples from 38–255 m depth were analysed.
• 3. Three macro‐epibenthic assemblages were identified in both the shallow (at 38–91 m) and deep shelf (90–255 m). Macroalgae bathymetric distribution was identified as the main factor explaining the segregation between shallow and deep shelf assemblages.
• 4. Two especially sensitive habitats were identified: maërl and crinoid beds; a third habitat was identified as Peyssonnelia beds, which represented the highest biomass on the whole shelf, with a similar species richness to the maërl beds. On the deep shelf, crinoid beds represented the highest biomass.
• 5. Habitat type had a significant effect on the distribution of demersal commercial species, most of them being more abundant in the two sensitive habitats mentioned and in the Peyssonnelia beds. Some species showed size‐specific habitat preferences.
• 6. Fisheries management in the area should take into account the resilience of these benthic habitats, and their importance from both ecological and sustainable fisheries management perspectives.

Copyright © 2008 John Wiley & Sons, Ltd.     

贵州省主要经济鱼类种类及开发应用前景

对贵州省主要经济鱼类种类和资源量进行调查,基本掌握了贵州省主要经济鱼类有34种.其中,鲤科鱼类22种,占64.7%;鲿科鱼类5种,占14.7%;鲶科、鮨旨科及鳢科鱼类各2种,各占5.9%;长臀鮠科鱼类1种,占2.9% .主要分布于乌江、赤水河、沅江、北盘江、红水河、柳江等水系.主要土著名特优经济鱼类资源年产量1 977t.目前,国内对翘嘴鲌、鲤、鲫、大口鲇、鲇、黄颡鱼、瓦氏黄颡鱼、长吻鮠、斑鳜、乌鳢和月鳢11种鱼类的研究已较成熟;对中华倒刺鲃、白甲鱼、瓣结鱼、华鲮、唇鲮、昆明裂腹鱼、四川裂腹鱼、岩原鲤、鲤、鲫、斑鳠、长臀鮠和大鳍鳠13种鱼类开展了养殖和繁殖研究,并取得了一些突破;适宜进行开发的鱼类有中华倒刺鲃、白甲鱼、华鲮、昆明裂腹鱼、四川裂腹鱼、岩原鲤、斑鳠、长臀鮠和长吻鮠等.     

浙江南部外海底层渔业资源量与可捕量的评估

2006年5月、8月、11月和2007年2月,对浙江南部外海渔场使用底拖网进行渔业资源调查．据其资料,使用扫海面积法估算浙江南部外海底层渔业资源量以及可捕量．结果表明：采集并鉴定的种类共416种,现存资源量为442525．89t,使用Camida估算模式和简化估算模式得到总可捕量分别为238077．32t和214625．06t．鱼类、甲壳类和头足类的资源平均密度及现存资源量分别为2374．68kg／km2和271225．74t、451．08kg／km2和51520．47t、875．17kg／km2和99957．98t．为防止资源盲目开发及资源衰退,浙江南部外海拖网捕捞结构宜进行控制和调整．     

六片式拖网在几内亚渔场的适用性

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。     

鱼类脲酶比活力研究

通过对鲤、团头鲂、鲫、草鱼、乌鳢、革胡子鲶、黄鳝、鲢和鳙9种食性不同的鱼的脲酶比活力进行比较，结果显示：食性与脲酶比活力存在一定的相关性。草食性与滤食性的草鱼和鲢、鳙脲酶比活力明显高于其他几种鱼，肉食性与杂食性鱼脲酶比活力明显要低。9种鱼脲酶主要分布在前肠和中肠，后肠脲酶比活力很低，与前、中肠相比存在显著差异。     

远东拟隆头鱼的物种厘定及重新描述

远东拟隆头鱼Pseudolabrus eoethinus(Richardson,1846)曾为日本拟隆头鱼P.japonicus(Houttuyn,1782)的同物异名。由于这2种拟隆头鱼外部形态十分相似,导致其分类上的误鉴,目前部分文献中仍存在同物异名。本文对采自福建沿海的远东拟隆头鱼标本重新进行了形态描述,并与日本拟隆头鱼进行了形态学比较研究,发现两者间存在明显的形态差异。远东拟隆头鱼头部具1条自口角稍前向后经眼下缘伸达胸鳍基部的弧状纹线,侧线鳞孔纹为2次二分叉状,背鳍起点前鳞片数为8,背鳍鳍棘间无黑斑等特征,可与日本拟隆头鱼(头部纹线较为平直、后端不达胸鳍基部,侧线鳞孔纹为3次以上二分叉状,背鳍起点前鳞片数为5,背鳍第3-6鳍棘间具有1黑斑)相区别。