珠江流域草鱼和鲢单位捕捞努力量渔获量时空分布特征及温度影响

文章采用随机等距抽样,调查了2016—2018年珠江流域9个采样点共计90艘船每天的渔获物产量及销售额。采用kruskal检验、广义加性模型和时间序列分析对草鱼(Ctenopharyngodon idellus)和鲢(Hypophthalmichthys molitrix)的单位捕捞努力量渔获量(Catch per unit effort,CPUE)时空变动特征及温度影响进行分析。结果显示,珠江流域草鱼和鲢产量在总渔获中占比分别为(6.6±8.1)%和(4.4±5.0)%,销售额占比分别为(6.0±8.2)%和(2.5±2.6)%;草鱼和鲢CPUE分别为(5.5±7.3)kg·(艘·月)?1和(5.6±10.3)kg·(艘·月)?1。草鱼和鲢CPUE在珠江中上游江段显著高于河口区域(P<0.05),与温度呈显著正相关关系(P<0.01),其时间变动主要受禁渔期影响;草鱼CPUE年际变化呈上升趋势,而鲢呈下降趋势。与历史数据相比,草鱼和鲢在渔获物中的质量占比均有明显增加,这可能主要得益于增殖放流和禁渔期制度。

Spatio-temporal patterns of CPUE of grass carp and silver carp and effect of temperature on CPUE in Pearl River basin

We investigated the production and economic benefits of grass carp(Ctenopharyngodon idellus)and silver carp(Hypophthalmichthys molitrix)in the Pearl River basin by using the method of isometric random sampling.A total of 90 vessels were daily surveyed from nine locations from 2016 to 2018.The kruskal test,generalized additive model and time series analysis were used to analyze the spatial and temporal patterns of CPUE(Catch per unit effort)of grass carp and silver carp and to explore the effect of temperature on the CPUE.The results show that the biomass of grass carp and silver carp attributed(6.6±8.1)%and(4.4±5.0)%respectively,to the total catches in the Pearl River basin,and produced(6.0±8.2)%and(2.5±2.6)%economic benefit of the total income.In addition,the CPUE was(5.5±7.3)and(5.6±10.3)kg·(vessel·month)?1,respectively.The CPUE of two species was significantly higher in the middle and upper reaches than that in the estuary area(P<0.05).The temporal variations in CPUE of grass carp and silver carp were mainly effected by closed season.Temperature had a significant positive effect on the CPUE of both species(P<0.01).The CPUE of grass carp and silver carp showed an increasing and decreasing trend with year,respectively.By contrast with the historical data,the biomass of both carps increased obviously in the past decade.The increasing production of grass carp and silver carp observed in this study might be largely benefited from proliferation and release as well as closed season.