Growth and life history of the mesopelagic mysid Meterythrops microphthalma in the southern Japan Sea
Growth and life history of the mesopelagic mysid Meterythrops microphthalma in the southern Japan Sea
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日本海南部中层糠虾小眼甲鱼的生长和生活史
DOI：
10.1093/plankt/14.12.1767
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发表时间：
1992
影响因子：
2.1
通讯作者：
T. Ikeda
中科院分区：
文献类型：
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作者：
T. Ikeda
1986年6月、9月和12月在富山湾用MTD网和1987年4月在大和海隆附近的沃茨用Norpac网进行了采样，调查了中层糠虾Meteryhrops microphthalma的种群结构。队列分析表明，每个样本中有三到四个年龄组。用von Bertalanffy函数描述该鱼种的生长，BL=29.22（1-e0.2975（t-0.3619）;其中BL为体长（mm），t为时间（年）。繁殖是季节性的少年释放从女性的marsupium在2月中旬。雌性在第二年的冬天达到成熟和繁殖，并可能在第二年再次繁殖。窝卵数为9-23只。男性需要更多的时间来成熟（年龄：2岁以上），寿命比女性长。根据最大的标本估计寿命为雌性3年，雄性4年。估计终生死亡率为1.040年-1。从湿重，干重和灰分含量的测定，年轻的幼虫在袋较重，有更大的有机物含量比老幼虫或小少年。这表明幼虫发育所需的能量最初储存在胚胎中。在生活史ofM. microphthalma看到的一般特征与其他非洄游中层甲壳类动物的报道是一致的，除了这个物种的生长速度非常缓慢。食物丰富和温度在日本海南部的中层区是不可能的主要原因，这种缓慢的增长ofM. microphthalma。相反，它的缓慢增长可能与缺乏micronectonic捕食者和极低的生态位竞争，一个独特的功能，日本海的中层群落。
Samplings with MTD nets were made in June, September and December 1986 in Toyama Bay, and with Norpac nets in April 1987 in waters around Yamato Rise, and population structure of the mesopelagic mysidMeteryhrops microphthalmawas investigated. Cohort analyses indicated three to four age groups in each sample. Growth of this species was expressed well by von Bertalanffy function, BL=29.22 (1–e0.2975(t–0.3619); where BL is body length (mm) and t is time (years). Reproduction was seasonal with juvenile release from the female's marsupium in mid-February. Females reach maturity and breed in winter of the second year, and possibly breed again in the following year. The brood size was 9–23. Males take more time to mature (age: 2+year) and live longer than females. Estimated longevity based on the largest specimens is 3 years for females and 4 years for males. Estimated life-time mortality is 1.040 year−1. From the determination of wet weight, dry weight and ash content, younger larvae in the marsupium are heavier and have greater organic content than do older larvae or small juveniles. This suggests that the energy required for larval development is deposited initially in the embryos. General features seen in the life history ofM.microphthalmaare consistent with those reported for other non-migrating mesopelagic crustaceans, excepting for the very slow growth rate of this species. Food abundance and temperature in the mesopelagic zone of the southern Japan Sea are unlikely major causes for this slow growth ofM.microphthalma. Instead, its slow growth may be related to the lack of micronektonic predators and extremely reduced niche competition, a unique feature of the mesopelagic community of the Japan Sea.