Trawl sampling of small pelagic fish off Angola: effects of avoidance, towing speed, tow duration, and time of day   总被引：1，自引：1，他引：0  

Misund  O. A.; Luyeye  N.; Coetzee  J.; Boyer  D. 《ICES Journal of Marine Science》1999,56(3):275-283

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不同条件延缓未受精卵激活对鱼类细胞电融合的影响     

吴滟傅洪拓  龚永生何新龙 熊贻伟 《广东海洋大学学报》2006,26(6):1-4

泥鳅未受精卵先在合成卵巢液、郝氏液中分别浸泡15、20、30min．然后再受精孵化，统计发育情况，结果表明，合成卵巢液可有效延缓未受精卵遇水后被激活的时间，郝氏液对延缓未受精卵被激活也有一定作用，但效果比合成卵巢液差。用合成卵巢液配制不同浓度胰酶处理受体卵进行细胞电融合实验．胰酶质量浓度为5mg／mL时．融合卵发育至囊胚期的比例比对照组（郝氏液）高2％．统计分析表明该差异是显著的（P〈0．05）；但发育至原肠期及孵出期的比例则与对照组无显著差异。胰酶质量浓度为2和1mg／mL时．融合卵发育到各阶段的比例均低于对照组，统计分析表明两者的差异是显著的（P〈0．05）。研究表明，溶液种类、胰酶浓度等对电融合卵的发育有明显的影响，但延缓受体卵的激活时间并不能提高电融合卵的出苗率。用郝氏液配制的2mg／mL的胰酶溶液处理受体卵，可获得较高比例的融合鱼。  相似文献   

Trophic structure of mesopelagic fishes in the Gulf of Mexico revealed by gut content and stable isotope analyses          下载免费PDF全文

Jennifer P. McClain‐Counts  Amanda W. J. Demopoulos  Steve W. Ross 《Marine Ecology》2017,38(4)

Mesopelagic fishes represent an important component of the marine food web due to their global distributions, high abundances and ability to transport organic material throughout a large part of the water column. This study combined stable isotope (SIAs) and gut content analyses (GCAs) to characterize the trophic structure of mesopelagic fishes in the North‐Central Gulf of Mexico. Additionally, this study examined whether mesopelagic fishes utilized chemosynthetic energy from cold seeps. Specimens were collected (9–25 August 2007) over three deep (>1,000 m) cold seeps at discrete depths (surface to 1,503 m) over the diurnal cycle. GCA classified 31 species (five families) of mesopelagic fishes into five feeding guilds: piscivores, large crustacean consumers, copepod consumers, generalists and mixed zooplanktivores. However, these guilds were less clearly defined based on stable isotope mixing model (MixSIAR) results, suggesting diets may be more mixed over longer time periods (weeks–months) and across co‐occurring species. Copepods were likely important for the majority of mesopelagic fishes, consistent with GCA (this study) and previous literature. MixSIAR results also identified non‐crustacean prey items, including salps and pteropods, as potentially important prey items for mesopelagic fishes, including those fishes not analysed in GCA (Sternoptyx spp. and Melamphaidae). Salps and other soft‐bodied species are often missed in GCAs. Mesopelagic fishes had δ¹³C results consistent with particulate organic matter serving as the baseline organic carbon source, fueling up to three trophic levels. Fishes that undergo diel vertical migration were depleted in ¹⁵N relative to weak migrators, consistent with depth‐specific isotope trends in sources and consumers, and assimilation of ¹⁵N‐depleted organic matter in surface waters. Linear correlations between fish size and δ¹⁵N values suggested ontogenetic changes in fish diets for several species. While there was no direct measure of mesopelagic fishes assimilating chemosynthetic material, detection of infrequent consumption of this food resource may be hindered by the assimilation of isotopically enriched photosynthetic organic matter. By utilizing multiple dietary metrics (e.g. GCA, δ¹³C, δ¹⁵N, MixSIAR), this study better defined the trophic structure of mesopelagic fishes and allowed for insights on feeding, ultimately providing useful baseline information from which to track mesopelagic trophodynamics over time and space.  相似文献   

乐清湾口海域春、秋季鱼类种类组成和数量分布   总被引：1，自引：0，他引：1  

闫丽娜  叶深  李德伟  周青松  谢旭  郑基  程郡  俞存根 《海洋与湖沼》2013,44(4):1062-1067

根据2012年4月(春季)、10月(秋季)在乐清湾口的大小门岛海域开展拖网渔业资源调查所获得的鱼类数据, 用渔获率作为鱼类资源数量分布的指标, 对乐清湾口调查海域的鱼类种类组成、区系特点、数量分布等进行了分析。结果表明, 乐清湾口海域春、秋两季共获得并鉴定出的鱼类有49种, 隶属于10目26科,其中以鲈形目最多, 有20种, 占鱼类总种数的40.8%; 鲱形目次之, 有9种, 占鱼类总种数的18.4%; 优势种有龙头鱼和刀鲚; 数量是秋季较多且分布较均匀; 根据鱼类适温性可将该海域的鱼类分为暖水性和暖温性2种适温类型, 其中暖水性种类占55.1%; 同时, 根据其生态习性, 可分为河口性、沿岸性和近海性3种生态类群。  相似文献   

Diadromy and longitudinal patterns of upstream penetration of freshwater fish in Taranaki,New Zealand     

Michael K. Joy  Ian M. Henderson  Russell G. Death 《新西兰海洋与淡水研究杂志》2013,47(3):531-543

Diadromous fish species dominate the New Zealand freshwater fish fauna and make up 15 of the 17 native fish species found on the Taranaki Ring Plain. Trajectories of occurrence in relation to elevation and distance from the sea are described for 11 diadromous and 2 non‐diadromous species using data from the New Zealand Freshwater Fish Database and data collected over the summer of 1997/ 98. Distinctive distributions were found for most of the species related to their differing migratory strategies and abilities. The species were ranked based on components of these trajectories to compare their penetrative ability. Comparison of the ranking methods used revealed they produced similar results. The ranking of the 11 diadromous species in Taranaki relative to each other revealed similar rankings to those for the same species from the West Coast of the South Island. The non‐migratory native fish, Cran's bully (Gobiomorphus basalis), was not found on the western side of the mountain. This distribution is thought to be the result of the local extinction of non‐migratory species in high gradient or unstable streams.  相似文献   

Comparative embryogenesis of Australian and South African viviparous clinid fishes (Blennioidei,Teleostei)     

《African Journal of Marine Science》2013,35(3):381-397

The study follows the embryogenesis of 16 species of viviparous clinid fishes (Clinidae, Teleostei), from the Cape south coast of South Africa and from Australia, with comparative remarks on the development of juveniles in oviparous species. The sperm intromitted into the female duct fertilise the eggs within the follicles. The embryos then develop in individual follicles, nourished by nutrients derived from the mother, until they are mature for release. During the reproductive season in the South African genera Clinus and Muraenoclinus, the female's ovaries harbour eggs and embryos at various stages of development, whereas in species of the Australian genera Heteroclinus and Cristiceps, most embryos in each ovary are at an approximately equal stage of development. The ovaries of the studied species fall into two groups: species of Heteroclinus and Cristiceps that produce numerous small eggs, and species of Clinus and Blennophis that produce fewer, larger eggs. As a consequence, Heteroclinus spp. and Cristiceps spp. bear and release high numbers of smaller embryos, of c. 10-13 mm long, whereas others (e.g. Clinus superciliosus, C. cottoides) bear fewer embryos, of up to 22 mm long. The organogenesis of various organs is described, with particular emphasis on chondrification and ossification. The onset of gut, sensory organ and skeletal development in Heteroclinus and related species occurs in embryos of 2.5-3.0 mm, whereas in Clinus spp. organ development starts in 5.0-6.0 mm embryos, and occurs in parallel both in the head capsule and at the caudal ends. Consequently, the pace of embryogenesis in the studied Australian small-egg species is faster in several aspects, and their embryos at the time of release are smaller than those of the large-egg species. The developmental sequences and related phenomena are discussed.  相似文献   

江西古生代鱼类   总被引：1，自引：0，他引：1  

刘亚光 《江西地质》1997,11(2):5-13

江西是古生代鱼类发育的重要地区之一。所获鱼类化石既有无颌类，又有丰盛的有颌类。前者之代表性属种是产在赣北志留纪地层的中华盔甲鱼和修水多鳃鱼；后者以胴甲类为主，产在中、晚泥盆世地层中，代表性属类有沟鳞鱼、星鳞鱼、浆鳞鱼、湖南鱼和江西鱼等。本文首次系统地介绍了各种鱼的主要特征、产地层位、生存环境等。  相似文献   

Population Structure of Blennius incognitos BATH 1968 (Pisces: Teleostei: Blen-niidae) during the Reproductive Period with Comments on Age and Growth of Small Benthic Littoral Fishes     

Kurt  Kotrschal Alfred  Goldschmid 《Marine Ecology》1981,2(3):225-240

Abstract. Length frequency distribution, condition factor and parasite infection of Blennius incog-nitus from three different areas near Rovinj, Yugoslavia have been investigated. Differences between considered parameters in three populations of B. incognitus have been found and discussed. Fishes were aged by otolith reading. Mean life span, growth rate, sex ratio and a sexual dimorphism in body size were noted in this littoral blenny. Our findings are discussed and compared with data on comparable littoral fishes.  相似文献   

The effects of fishing on demersal fish communities of the Scotian Shelf   总被引：1，自引：5，他引：1  

Zwanenburg  K. C. T. 《ICES Journal of Marine Science》2000,57(3):503-509

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南海鱼类寄生粘孢子虫──Ⅱ．篮子鱼两极虫与尖吻鲈尾孢虫两新种     

吴灶和  吴建平  华鼎可 《热带海洋学报》1994,(3)

篮子鱼两极虫，新种Ｍｙｘｉｄｉｕｍｓｉｇａｎｕｍｓｐ．ｎｏｖ．寄生于篮子鱼Ｓｉｇａｎｕｓｓｐ．胆囊。孢子缝面观菱形，正面观椭圆形。孢子表面具有６条条纹。孢子长１１．４μｍ，宽６．９μｍ；极囊直径３．３μｍ；囊间距２．８μｍ。尖吻鲈尾孢虫，新种Ｈｅｎｎｅｇｕｙａｌａｔｅｓａｓｐ．ｎｏｖ寄生于尖吻鲈Ｌａｔｅｓｃａｌｃａｒｉｊｅｒ鳃部。孢子呈倒梨形。孢子长８．９μｍ，宽５．７μｍ，厚４．９μｍ；极囊长２．８μｍ，宽１．８μｍ；尾长１６．０μｍ。  相似文献