Notes on the Bathypelagic Fauna of the Seas Around South Africa

The preliminary results of a study of the endemic giant tortoise population of Aldabra Atoll in the Indian Ocean (Geochehne gigantea Schweigger) are briefly described. Their number would appear to have increased dramatically since the turn of the century to their present level of some 141 000 individuals. Crude estimates of mortality and reproductive rates are also given.     

捕捞压力和气候变化对东海马面纯渔获量的影响

为了研究捕捞压力和气候变化对东海马面纯（Navodon spp．）渔获量的影响,对1976年～2006年的东海马面纯渔获量进行了分析。东海马面纯渔获量可划分成因捕捞效应所产生的趋势变化和因气候变动所导致的渔获量变动,前者可用Fox模型来拟合。Fox模型拟合结果显示,东海马面纯渔获量与捕捞努力量显著相关（P〈0．01）。移除捕捞压力增长引起的变化趋势后,其渔获量变动与热带气旋影响指数、东海海表温度、东海冬季季风和黄海夏季季风呈显著正偏相关（P〈0．03）,与热带气旋影响指数、黄海冬季季风及长江流域和东海沿岸降雨呈显著负偏相关（P〈0．03）。根据捕捞努力量和气候变量对东海马面纯渔获量进行拟合,结果显示,拟合的渔获量与实际渔获量显著相关（R=0．91,P〈0．01）,说明捕捞压力和气候变化显著影响东海马面纯渔获量的变动。此外,由于未来气候的变化,东海马面鲍渔获量可能出现更大波动。     

The large‐scale stocking of young anadromous whitefish (Coregonus lavaretus) and corresponding catches of returning spawners in the River Tornionjoki,northern Baltic Sea

Stocking and fishing effort are two important potentially conflicting factors in fish stock management that require appropriate assessment to ensure a sustainable fishery. In the River Tornionjoki, which discharges into the northern Baltic Sea, a summer‐ascending whitefish, Coregonus lavaretus L., stock has long been a target by traditional dipnet fishing. Enhancement stocking of young whitefish started in the River Tornionjoki in the 1970s after a collapse in catches, with millions of age‐0 whitefish stocked annually in the river, but after about three decades, the stocking rates were considerably reduced. As a result, dipnet catches of whitefish in the Kukkolankoski Rapids rose simultaneously, peaking in the 1980s and 1990s, and then subsequently decreased. There was a significant positive correlation between stocking intensity and catch, both in weight and in numbers, revealing a strong relationship between whitefish releases and dipnet catch. Changes in gillnet fishing effort in the sea affected dipnet catches in weight as well as in mean size of captured whitefish. When the combined effect of stocking and gillnet effort was evaluated, only stocking significantly affected dipnet catches.     

山东半岛南部沿岸中国对虾放流数量对秋汛产量的影响

根据１９８３～１９９８年山东半岛南部沿海对虾放流增殖结果,对秋汛对虾产量与放流数量之间的关系进行了研究。结果表明：秋汛对虾产量随放流数量的增加而增加,二者呈Ｙ＝３６３．７＋１２６．４Ｘ相关关系（ｒ＝０．９１８）。     

硇洲岛周围水域虾拖网虾渔获组成

根据2005年渔业资源监测船生产调查资料和现场取样数据,运用数理统计方法分析了虾拖网虾渔获组成、生物学特征以及月份变化等。结果表明:硇洲岛周围水域虾拖网捕获的虾类主要是沿岸性底栖虾类,渔获中优质虾种少,幼虾比例高,墨吉明对虾、日本囊对虾、哈氏仿对虾是虾拖网渔业的主捕虾种,虾渔获组成存在明显的月份变化。为合理利用虾类资源和促进虾渔业可持续发展,应根据虾类特性开发适宜广东沿海虾拖网的选择性捕捞技术,减少幼虾兼捕量。     

Importance of the River Teviot to Atlantic salmon, Salmo salar, rod catches in the River Tweed, Scotland

Abstract  The body mass distributions and variations in abundance of the spring and autumn catches of Atlantic salmon, Salmo salar L., were compared between fisheries above and below the confluence of the rivers Tweed and Teviot, Scotland. Significant differences between the distributions were found over three periods, one in spring and two in autumn, when salmon catches were high. Correlations were found between abundance trends for periods when distributions were similar or dissimilar. Abundance of salmon returning to the River Teviot was proportional to the main river. However, its population structure differed when abundances were high, suggesting different survival strategies. It appears that changes in the numbers returning to the river were resultant of changes in the marine rather than freshwater environment.     

卡死克对草地天敌昆虫通缘步甲的影响

试验研究了卡死克对通缘步甲成虫的急性致死毒性及田间撒施卡死克毒饵后对其种群数量消长的影响。室内口腔灌喂250ppm浓度的卡死克药液2μl／头后的第1～15天，灌药组与灌清水组的存活率均在70～90％，统计结果无显著差异，说明药剂对该步甲元急性致死毒性。在毒饵撒施后的7～17天，采用陷阱诱捕法调查对通缘步甲田间种群数量的影响，结果表明：处理区与对照区的日均诱捕数量为28．3和28．5头，两区间的差异并不显著。卡死克既不杀伤草地上游猎捕食的通缘步甲又能有效控制蝗虫种群数量的增长，使其能够发挥控制害虫的作用。通缘步甲发生数量大，与蝗虫种群消长有跟随现象，是一种值得研究保护利用的优势天敌种类。     

长江靖江段沿岸似鳊的时间格局及生长特征

为了解长江下游沿岸似鳊（Pseudobrama simoni）的种群变动及生长状况,研究了2002-2009年间在靖江沿岸用定置张网采集的每月2次或3次共237份渔获物样本。结果表明：237份样本共有鱼类73 960尾、409 256.23 g。其中似鳊4 253尾、39 618.05 g,分别占总渔获量的5.75%和9.68%。平均每样本19尾、180.08 g,最高达145尾、1714.6 g。时间格局分析表明,似鳊月渔获重量呈非平稳的随机过程,对2002-2009年的月渔获重量进行ARIMA建模拟合,建立了方程为 (1－0.387B)（1－B¹²）lny_t=（1－0.555B¹²）e_t的ARIMA（1,0,0）（0,1,1）₁₂的预测模型,该模型对2003-2009年的预测精度达83.21 %～93.90%。对2005年采集的全部个体作性别、年龄和生长特征分析,显示似鳊的雌雄性比为1∶2.3。雄性有1～3龄3个年龄组,雌性只有1～2龄2个年龄组,年龄结构明显低于姚江和钱塘江种群。雄性的Von bertalanffy生长方程为：体长L_t=147.17×［1－e^{－0.1648×(t+3.2036)}］,体重W_t=44.36×［1－e^{－0.1648×(t+3.2036)}］^2.785;推算的渐近体长L_∞为147.17 mm,渐近体重W_∞为44.36 g。     

赣江峡江至南昌段鱼类资源现状

为了解赣江中下游的鱼类资源现状,在2009年6月至2010年6月,分别于丰水期、平水期和枯水期对赣江峡江至南昌段的干流及2条支流共10个点的鱼类资源进行了3次调查。调查结果表明,该流域内共发现记录鱼类90种(亚种),隶属6目16科60属,以鲤形目为主,鲶形目与鲈形目的居中,鲱形目、合鳃鱼目和颌针鱼目极少;且优势种类主要为鲤(Cyprinus carpio Linnaeus)、鲫(Carassiu auratus)、黄颡鱼(Pelteobagrus fulvidraco Richardson),江湖洄游性鱼类(如青鱼Mylopharyngodon piceus、草鱼Ctenopharyngodon idellus、鲢Hypophthalmichthys molitrix、鳙Aristichthys nobilis等)数量大量减少,而一些江海洄游性鱼类和珍稀鱼类(如中华鲟Acipenser sinensis、鯮Luciobrama macrocephalalus、鲥Macrura reevesii等)在此次调查中没有发现。与历史资料相比,赣江峡江至南昌段水域的鱼类种类组成变化较大,资源量明显降低,小型化趋势明显。     

达里湖鲫和东北雅罗鱼捕捞群体资源量和合理捕捞量的估算

由各龄组Ｐ／Ｂ系数和残存率估算出达里湖鲫和东北雅罗鱼可捕捞群体的资源量分别为６０～６７万ｋｇ和４５万ｋｇ，并指出目前捕捞量应以４０～４５万ｋｇ为宜，如资源恢复，可保持在６０～７０万ｋｇ的高产水平。