Protecting window‐size female American lobster,Homarus americanus,to increase egg production     

Robert MacMillan  Michel Comeau  Manon Mallet 《新西兰海洋与淡水研究杂志》2013,47(1):525-536

A new conservation measure aimed at protecting the larger broodstock (females with a carapace length between 115 and 129 mm, i.e., window‐size females, WSF) to enhance egg production was implemented in 2003 for the American lobster (Homarus americanus) fishery in the southern Gulf of St. Lawrence, Canada. To assess the effectiveness of this new measure, a tagging project was carried out between 2004 and 2007 in the Hillsborough Bay area with the collaboration of local harvesters. Based on a single mark‐recapture Petersen model, the estimated catch rates of WSF not carrying eggs under the abdomen in the study area varied between 40% and 53%. The catch‐per‐unit‐effort (animals per 100 traps) of both berried (egg‐bearing) and non‐berried WSF increased from 0.2 to 0.8 and 1.0 to 1.6, respectively, between 2004 and 2007. Based on the estimated number of non‐berried WSF in the population observed during the spring fishery between 2004 and 2007, the potential total egg production for WSF was estimated at 1.1 billion in the study area. From this total, 515 million eggs would have been produced by WSF directly protected by the conservation measure, i.e., females that would have been harvested if not for the new regulation. Finally, the contribution of berried WSF to the annual egg production in the study area increased from 4% to 23% between 2003 and 2007 based on the at‐sea sampling programme and the fecundity curve. WSF that represented 10% of the total berried female population in 2007 contributed 23% of the annual egg production. Hence, the protection of WSF seems to be an effective conservation measure to increase egg production based on the catch‐per‐unit‐effort and egg production.  相似文献   

Observations of temperatures in some Rotorua district lakes     

J. Irwin 《新西兰海洋与淡水研究杂志》2013,47(4):591-605

A preliminary study has been made of temperatures in some of the lakes of the Rotorua district, in the North Island of New Zealand. Seasonal and diurnal variations are discussed. Two main thermal structure types are present. One, in which stratification is irregular or absent, is present in lakes that are relatively shallow and large in area, and the other, in which there is thermal Stratification from early summer to early winter, is present in lakes that are comparatively deep and large in area or else of medium depth and size.  相似文献   

大菱鲆(Scophthalmus maximus)繁殖期卵子和卵巢液中磷酸酶活性变化及其与受精率相关性   总被引：1，自引：0，他引：1  

贾玉东  孟振  刘新富  高淳仁  牛华欣  雷霁霖 《海洋与湖沼》2013,44(6):1530-1535

以大菱鲆为实验材料,研究其繁殖周期内卵子和卵巢液中磷酸酶活性变化规律及其与受精率相关性。结果显示：在大菱鲆繁殖周期内,卵子碱性磷酸酶和酸性磷酸酶活性呈相反的变化趋势,且排卵中期卵子碱性磷酸酶和酸性磷酸酶活性分别显著低于和高于早期和晚期（P＜0.05）,而卵巢液中碱性磷酸酶和酸性磷酸酶活性呈同卵子中相反的变化趋势;此外卵子碱性磷酸酶和酸性磷酸酶及卵巢液酸性磷酸酶活性同受精率显著相关（P＜0.05）。以上结果表明,大菱鲆卵子和卵巢液中碱性磷酸酶和酸性磷酸酶活性同受精率存在着显著相关性,其活性变化在一定程度上反映卵子质量优劣,可作为评判卵子质量辅助指标。  相似文献   

Cyclonic eddies reveal Oegopsida squid egg balloon masses in the Agulhas Current,South Africa     

《African Journal of Marine Science》2013,35(2):239-246

In 2005, 2006, 2007 and 2011, distinct Oegopsida squid egg masses were observed by scuba divers on the narrow southern KwaZulu-Natal (KZN) shelf in depths of 35–50 m off the coastal resorts of Park Rynie, Pumula and Port Edward, South Africa. In 2006, larvae in the egg balloons were sampled. DNA barcoding (i.e. cytochrome c oxidase subunit 1 sequencing) linked the larvae to the genus Lycoteuthis, a group commonly found on the continental slope of the Agulhas Bank and the west coast of South Africa. In all cases, the sightings were concomitant with low water temperatures of 14–18 °C, indicative of shelf edge upwelling. Historical ship-collected CTD data show these cooler waters to originate from a depth of 100–180 m on the KZN continental slope. Complementary satellite imagery revealed the cooler water and discoveries of the egg balloons to be coincident with cold core cyclonic eddies embedded in the shoreward boundary of the Agulhas Current. The temperature data suggest that these egg balloons, in the absence of cyclonic eddy activity, would normally be found in the current on a density surface at a depth of ～130 m where velocities are typically around 100 cm s^–1.  相似文献   

厦门港中华哲水蚤卵型研究     

杨青  曹文清  林元烧  桂月  李少菁 《海洋学报》2007,29(5):117-122

对厦门港中华哲水蚤(Calanus sinicus)的卵型进行观察和研究,获得主要结果如下:(1)厦门港中华哲水蚤仅存在一种基本卵型,属于无鞘卵,但卵表面具有透明、柔软的胞膜(blister),胞膜呈褶皱结构;(2)胞膜可因外力而脱落,但胚胎仍可以正常发育;(3)在实验室水温为16~22℃条件下,受精卵均可正常孵化与发育;(4)胞膜的厚度有一定的变化,它随着水温的升高有减小的趋势.卵型分析与孵化实验均证实:厦门港中华哲水蚤不存在休眠卵(dormant egg)或滞育卵(diapause egg).  相似文献   

Fecundity variation in Icelandic summer-spawning herring and implications for reproductive potential   总被引：2，自引：0，他引：2  

Oskarsson  Guthmundur J.; Taggart  Christopher T. 《ICES Journal of Marine Science》2006,63(3):493-503

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几种动物精卵识别机制     

刘慧慧  李太武  苏秀榕 《海洋湖沼通报》2004,200(1):16-21

动物受精是指两性配子细胞相结合生成合子的过程,亲代通过受精将遗传物质传给子代,它是衔接亲代与子代的桥梁,保持了物种的延续.精卵识别是受精的起始步骤,是指配子细胞通过各自表面的受精蛋白--糖蛋白类物质的特异性相互作用识别并结合,完成受精过程.本文着重介绍目前研究比较清楚的小鼠、猪、海胆和鲍等的精卵识别机制,比较了哺乳动物和无脊椎动物之间的联系和差别,进一步说明不同动物通过各自性细胞表面的糖蛋白完成精卵识别过程,并由相应糖蛋白的不同组成和结构决定了该识别过程的特异性.  相似文献   

Sub-Lethal Effects of Elevated Concentration of CO<Subscript>2</Subscript> on Planktonic Copepods and Sea Urchins   总被引：2，自引：0，他引：2  

Haruko Kurihara  Shinji Shimode  Yoshihisa Shirayama 《Journal of Oceanography》2004,60(4):743-750

Data concerning the effects of high CO₂ concentrations on marine organisms are essential for both predicting future impacts of the increasing atmospheric CO₂ concentration and assessing the effects of deep-sea CO₂sequestration. Here we review our recent studies evaluating the effects of elevated CO₂ concentrations in seawater on the mortality and egg production of the marine planktonic copepod, Acartia steueri, and on the fertilization rate and larval morphology of sea urchin embryos, Hemicentrotus pulcherrimus and Echinometra mathaei. Under conditions of +10,000 ppm CO₂ in seawater (pH 6.8), the egg production rates of copepods decreased significantly. The survival rates of adult copepods were not affected when reared under increased CO₂ for 8 days, however longer exposure times could have revealed toxic effects of elevated CO₂ concentrations. The fertilization rate of sea urchin eggs of both species decreased with increasing CO₂ concentration. Furthermore, the size of pluteus larvae decreased with increasing CO₂ concentration and malformed skeletogenesis was observed in both larvae. This suggests that calcification is affected by elevated CO₂ in the seawater. From these results, we conclude that increased CO₂ concentration in seawater will chronically affect several marine organisms and we discuss the effects of increased CO₂ on the marine carbon cycle and marine ecosystem. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

An application of the annual egg production method to estimate the spawning biomass of cod (Gadus morhua L.), plaice (Pleuronectes platessa L.) and sole (Solea solea L.) in the Irish Sea   总被引：1，自引：0，他引：1  

Armstrong  M. J.; Connolly  P.; Nash  R. D. M.; Pawson  M. G.; Alesworth  E.; Coulahan  P. J.; Dickey-Collas  M.; Milligan  S. P.; O'Neill  M. F.; Witthames  P. R.; Woolner  L. 《ICES Journal of Marine Science》2001,58(1):183-203

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超远缘鱼类—斑马鱼和泥鳅—受精卵的激光融合   总被引：2，自引：0，他引：2  

张闻迪  赵白  姚纪花  邹建华  王秋 《中国海洋大学学报(自然科学版)》1992,(3)

利用激光诱导方法对不同科鱼类,鲤科(Cyprinidae)的斑马鱼(Brachydanio Rerio)和鳅科(Cobitidae)的大鳞副泥鳅(Paramisgurnus dabryanus Sauvage)受精卵进行的融合实验结果表明:不同科间的鱼类受精卵可以融合并继续存活发育,有的可发育至初孵仔鱼。但是,其融合、发育表现出与亲缘关系较近的鱼卵的融合、发育有较大的差异。  相似文献