莱州湾芙蓉岛人工鱼礁区鰉资源分布特征及其与环境因子的相关性分析

Distribution characteristics of Liza haematocheila and its relationship with environmental factors in Furongdao artificial reef zones, Laizhou Bay, China

为研究环境因子对人工鱼礁区鰉分布的影响,实验以莱州湾芙蓉岛人工鱼礁区鰉为对象,根据2014—2017年春季和秋季礁区三重刺网调查数据,主要应用GAM模型研究了水温、盐度、pH、溶解氧、饵料生物和人工鱼礁等环境参数以及年份、月份对鰉单位捕捞努力量渔获量(CPUE)和各站位平均体长的影响。结果显示,春季礁区和非礁区CPUE差异不显著,秋季礁区CPUE高于非礁区,是非礁区的3.53倍。礁区和非礁区体长差异不显著。三因素方差分析表明,鰉CPUE受到年份、月份、人工鱼礁、年份和月份的交互作用影响,平均体长则主要受到年份的影响。Delta GAM模型表明,人工鱼礁和水温对CPUE影响显著,鰉在人工鱼礁区出现的概率大于非礁区,随着水温的升高,鰉出现的概率降低;CPUE呈现先升高后降低的趋势,并在8°C达到最高值;饵料浮游植物丰度和浮游动物丰度是影响鰉平均体长的关键因子,当硅藻丰度小于3×105个/m3时,鰉平均体长随硅藻丰度上升而下降,随后趋于稳定;鰉平均体长随浮游动物丰度增加而呈现降低趋势。研究表明,鰉主要分布在秋季水温较低时的人工鱼礁区,体长较大的鰉主要出现在硅藻丰度和浮游动物丰度较低的区域。

Abundance of Liza haematocheila has declined rapidly since the 1980 s in Bohai Sea,due to the increasing fishing pressure caused by the change of fishery methods.Furongdao artificial reefs(ARs),located in Laizhou Bay,has provided a good habitat for L.haematocheila,making it one of the major fish resources in the AR area.In order to explore the response of L.haematocheila to environmental factors,the effect of environmental factors,artificial reefs,food abundance on CPUE and mean standard length of L.haematocheila were analyzed using GAM model.L.haematocheila were collected by trammels survey of Furongdao ARs during 2014-2017.The results showed that there was no significant difference between average CPUE values of artificial reef area and natural area in spring(P=0.362),however,the CPUE in AR area is 3.53 times CPUE in the control area in the autumn.Three-way ANOVA showed that CPUE is significantly affected by year,month,artificial reefs and interaction effect of year and month(P<0.01).Average length was affected by year(P<0.01).Results of Delta GAM showed that the probability that L.haematocheila occurs was significantly influenced by temperature and whether the site is in the AR area.The probability of presence is higher in AR area than in the natural area.As temperature increases,probability of presence decreases.CPUE increases when temperature is below 8℃and then decreases.Mean standard length of L.haematocheila is influenced by abundance of Bacillariophyta and zooplankton.When abundance of Bacillariophyta is smaller than 3×10^5 cells/m^3,mean standard length decreases with the increase of the abundance of Bacillariophyta,and then tends to stabilize change.Mean standard length decreases with abundance of zooplankton rises.In conclusion,L.haematocheila is mainly distributed in the AR area at low temperature,and large fish is mainly distributed in the area with low abundance of Bacillariophyta and zooplankton.