黄海中部夏季鳀鱼卵、仔稚鱼分布与早期生长特征

Distribution and early growth characteristics of anchovy eggs， larvae and juveniles in the central Yellow Sea in summer

摘要:

鳀（Engraulis japonicus）是黄海海域重要的捕捞对象，也是蓝点马鲛（Scomberomorus niphonius）等大型鱼类的主要饵料。探究鳀早期生活史阶段的分布及生长特征，是深入了解鳀补充机制的重要基础。基于2019年夏季黄海中部断面（119.7°E~123.5°E，35.5°N~36.5°N）调查数据，探究了鳀鱼卵、仔稚鱼的分布特征；分析比较了5种分布模型，选取Tweedie GAM模型研究了鳀鱼卵、仔稚鱼分布与环境因子的关系；基于鳀仔稚鱼耳石微结构分析，估算了鳀仔稚鱼的日龄和体长组成，逆推孵化日期，构建幂函数早期生长方程。结果显示，2019年夏季在山东半岛南部35.5°N断面海域形成鳀鱼卵的密集分布区，仔稚鱼密集分布区为123.5°E、35.5°~36.5°N纵向断面海域。盐度对鱼卵、仔稚鱼的分布都有显著影响，最适盐度为30~32；温度仅对鱼卵的分布有显著影响，最适温度为23~26 ℃。本研究共鉴定和分析211尾鳀仔稚鱼的日龄，体长为4~24 mm，优势体长组为12~14 mm，日龄为12~40 d，优势日龄组为18~20 d；耳石增长率为3.08~5.90 μm/d，其变化趋势在2个航次间差异显著，这可能与月份间的温度差异有关。本研究为鳀资源的早期生长和补充机制提供了科学依据。

Abstract:

Anchovy（Engraulis japonicus）is an important fishing target in the Yellow Sea， and it is also the main prey for large fishes such as Japanese-Spanish mackerel.Exploring the distribution and early growth characteristics of anchovy is important for understanding of the recruitment mechanism.In this study， based on the survey data of the cross-section in the central Yellow Sea in the summer of 2019， the relationship between the distribution of eggs， larvae and juveniles and environmental factors was investigated using Tweedie GAM model. Furthermore， based on the otolith microstructure analysis， the daily age and body length composition of larvae and juveniles were estimated， and the early growth equation of power function was constructed by extrapolating the hatching date.The results showed that in the summer of 2019， a dense distribution area of anchovy eggs occurred in the line section of 35.5°N in the south of Shandong Peninsula， and the dense distribution area of larvae and juveniles occurred in the area of 35.5°N-36.5°N along 123.5°E longitudinal sections.Salinity has a significant effect on the distribution of anchovy eggs， larvae and juveniles， the optimum salinity range was 30-32，on the other hand， the water temperature only has a significant effect on the distribution of anchovy eggs， and the optimum temperature range was 23-26 ℃.Analysis of daily otolith increment for 211 larvae and juveniles showed that the range of body length was 4-24 mm with the dominant length group of 12-14 mm， the age range was 12-40 days with dominant age group of 18-20 days， and the otolith growth rate ranged from 3.08 μm/d to 5.90 μm/d.The variation pattern in the daily otolith growth rate of larvae and juveniles was different between samples in July and August， which might be related to the difference in the water temperature between different months.This study provides scientific basis for the early growth and recruitment mechanism of anchovy resources.