东太平洋不同海区茎柔鱼渔业生物学的初步研究

根据我国鱿钓船多年在秘鲁、智利和哥斯达黎加外海生产调查所采集的茎柔鱼样本,对3个不同作业海区茎柔鱼渔业生物学特性进行比较分析。研究表明,秘鲁、智利和哥斯达黎加外海茎柔鱼胴长范围分别为209～1 149 mm、166～837 mm和204～429 mm,优势胴长分别为250～400 mm、300～450 mm和250～350 mm,对应的渔获物中雌雄性比平均值分别为3.87∶1、2.50∶1、3.75∶1。根据胴长组成以及性成熟,认为秘鲁外海存在大型、中型和小型3个群体,智利外海以中型群体为主体并存在少量的大型群体,哥斯达黎加外海以小型群体为主体并存在少量的中型群体。秘鲁和智利外海茎柔鱼体重与胴长关系式的生长参数b值为3.06～3.17,而哥斯达黎加外海为2.57～2.63。秘鲁和智利外海茎柔鱼性腺成熟度均以Ⅰ级和Ⅱ级为主,而哥斯达黎加外海则以Ⅱ、Ⅲ和Ⅳ级为主。各月间摄食等级差异变化较为显著,但基本上以0～2级为主体。研究表明,3个海区茎柔鱼种群结构和生物学特性总体上有所差异。研究亮点:首次对秘鲁、智利和哥斯达黎加外海3个不同作业海区茎柔鱼渔业生物学特性进行比较分析,研究认为秘鲁外海存在大型、中型和小型3个群体,智利外海以中型群体为主体并存在少量的大型群体,哥斯达黎加外海以小型群体为主体并存在少量的中型群体。生长参数存在差异,各月间摄食等级差异变化较为显著。研究表明,3个海区茎柔鱼种群结构和生物学特性总体上有所差异。

Comparison of fishery biology for Dosidicus gigas from three different areas in the Eastern Pacific Ocean

According to the sampled squid,Dosidicus gigas,collected from the fishing and survey by Chinese squid fishing boats for many years off EEZ of Peru,Chile and Costa Rica,the biological characteristics of D.gigas form three different fishing areas are compared.The results indicated that their mantle lengths of D.gigas off EEZ of Peru,Chile and Costa Rica ranged from 209 to 1 149 mm,from 166 to 837 mm and from 204 to 429 mm respectively,their dominant mantle lengths were 250-400 mm,300-450 mm and 250-350 mm accordingly,and their average sex ratio in the catch were 3.87∶1,2.50∶1 and 3.75∶1 respectively.Based on the mantle length composition and sexual maturity,it is suggested that three groups including large-sized,medium-sized and small-sized groups that existed off EEZ of Peru,the main medium-sized group and a small group of large-sized group are distributed off EEZ of Chile,and the main small-sized group and a small amount of medium-sized groups existed off EEZ of Costa Rica.Off waters of Peru and Chile,the value of growth parameters for the relationship between body weight and mantle length reached 3.06-3.17,while off waters of Costa Rica the value is 2.57-2.63.Off waters of Peru and Chile,the maturity stage of D.gigas mainly composed of stage Ⅰ and stage Ⅱ,while off waters of Costa Rica stages Ⅱ,Ⅲ and Ⅳ are dominant.The changes in monthly feeding level have significant difference,but the levels from 0 to 2 are the main.It is concluded that the population structures and biological characteristics of D.gigas in the three fishing areas have a difference as a whole.