舟山渔场针乌贼(Sepia andreana)的生物学特性及其渔场分布变迁

BIOLOGY AND RESOURCE OF CUTTLEFISH SEPIA ANDREANA IN ZHOUSHAN FISHING AREA

采用海洋生物资源调查研究方法,进行了舟山渔场针乌贼生物学特征及其渔场分布变迁的研究。结果表明,针乌贼胴长范围为98—178mm、平均为143.1mm,体重范围为119.4—733.7g、平均为403.8g,卵巢成熟度以4、5期为主、分别占总雌体数的36.92%和24.62%、怀卵数为77—745egg/female,摄食强度范围为0—4级,以0—1级为主,雌性摄食强度高于雄性;胴长与体重的关系为Y=-41.0709-0.5718X+0.0255X2,内壳长与胴长的关系为Y=0.8709+1.0124X,卵巢重与胴长的关系为Y=124.3780+1.4004X;历史上主要分布在北方海区的针乌贼,近几年来逐步在舟山渔场出现,并且渔获数量有不断增加的趋势,渔场分布发生了变迁。

Cuttlefish Sepia andreana usually lives in northern part of Chinese maritime, However, it was found recently in Zhoushan fishing area in the East China Sea, and its population had been increasing constantly, This research is to better understand the reason in biology and the resource change of the species. The cuttlefish samples were collected three times from Zhoushan Shenjiamen market in Feb, ,March and April 2004, respectively. The biological characteristics of the species, including community composition, growth rate,reproduction,and ingestion were studied statistically. The results were analyzed with SPSS. The mean size of S, andreana was 143.1 mm in a range of 98 to 178mm. No significant difference was found between male and female in body length, shell length, and shell weight, except the total weight. The sex ratio of female to male was 1 ： 0.58. Close correlation in power function was found between the body weight and body length in three groups of male, female and mixed ones, and significant linear relationships were found between shell length and （body length and body weight）, and between shell weight and body weight. The gonad weight showed a significant linear relationship with the nidamental gland weight,body length and body weight. Quantification in this study showed that since 1980＇s S. andreana had been fished in Zhoushan fishing area year-round, but it＇s the catch had been increasing. We inferred that three reasons were responsible for the increase. 1） Global climatic change caused water temperature variation southward-shifting isotherm by which the species distributed closely;2）Continuous fishing has caused the change in ecological succession, creating gaps in ecological niche; 3 ） Coastal constructions and buildings resulted in marine hydrological change in coastal areas, which influenced the conditions of sea flow, salinity and nutrition for plankton and ultimately for higher-lever marine creatures. Detail research and regulation implementation are important to protect the species. As a new resource in Zhoushan fishing area,S, andreana must be protected and used wisely. Future regulation should specify the spawning ground, proper fishing quantity and season in favor of sustainable use of this resource.