Age, growth, and reproduction of the bitterling (Paracheilognathus imberbis) in a shallow Chinese Lake

Age, growth, and reproduction of the bitterling, Paracheilognathus imberbis (Gunther), in Niushan Lake were studied between 1998 and 1999. Annuli on the scales were clear and could be used as valid indicators of age. The population of the fish comprised only one age group. The growth rate of males was markedly greater than that of females. The fish were multiple spawners, reaching maturity in the second year. Minimum size for males at maturity was 32.9 mm in total length and 0.30 g in weight; for females, the minima were 41.0 mm and 0.73 g. During the breeding season, both sexes exhibited secondary sex characteristics, and the ratio of males to females was 1: 1.04 (n = 104). The size of mature eggs averaged 3.12 mm in length by 1.03 mm. in width. Fecundity per female for one age group ranged from 38 to 189 eggs, with an average of 93 eggs (n = 80).

青岛近海六种海产鱼染色体组型的比较研究

采用活体注射秋水仙碱制备鱼类肾细胞染色体、PHA肌肉注射制备肾细胞染色体和鱼类早期胚胎制备染色体等多种方法。以空气干燥法制片Giemsa染色，对鲻鱼Mugil cephalus Linnaeus、真鲷Pagrosomus major（Temminck et Schlegel）、黑鲷Sparus macrocephalus（Basilewsky）、黑鮶Sebastes schlegeli （Hilgendorf）、石鲽Kareius bicoloratus （Basilewsky）、牙鲆Paralichthys olivaceus （Temminck et Schlegel）等分属四目、五科的六种海产鱼的染色体组型进行了考察和分析。研究结果表明：1、一般活体注射秋水仙碱制备海产鱼肾细胞染色体方法的有丝分裂指数虽然略低于PHA制备肾细胞染色体方法的有丝分裂指数。但它是最快最简便且很有效的方法，利用鱼类早期胚胎制备海产鱼染色体标本的方法也很有效，但要受到生物季节的限制。2、通过对六种海产鱼染色体组型分析得到，鲻鱼为48条端部着丝点染色体；真鲷的二倍体2n=48，有1对亚端部着丝点染色体。其余全部为端部着丝点染色体；黑鲷的二倍体2n=48。有3对中部着丝点染色体。2对亚中部着丝点染色体，其余全部为端部着丝点染色体。黑鮶的二倍体2n=48，有1对中部着丝点染色体，其余全部为端部着丝点染色体，石鲽的二倍体2n=48。全部为端部着丝点染色体；牙鲆的二倍体2n=48，全部为端部着丝点染色体。本文还对鱼类染色体的多态现象以及染色与进化的关系进行了讨论。

Life history cycles of flatfish species in the Bohai Sea, China

This paper provides basic information on the general ecology and life history cycles of various flatfish species in the Bohai Sea, China. The species studied are Paralichthys olivaceus (Temminck & Schlegel), Cleisthenes herzensteini (Schmidt), Eopsetta grigorjewi (Herzenstein), Verasper variegatus (Temminck & Schlegel), Pleuronichthys cornutus (Temminck & Schlegel), Pseudopleuronectes yokohamae (Gunther), Pseudopleuronectes herzensteini (Jordan & Snyder), Kareius bicoloratus (Basilewsky), Zebrias zebra (Bloch), Cynoglossus semilaevis Gunther, Cynoglossus abbreviatus (Gray) and Cynoglossus joyneri Gunther. Information on reproduction, eggs and larval distribution, growth and adult abundance is presented. Based on the biology and ecology of these flatfish, artificial enhancement of the commercial species in the Bohai Sea is discussed.