南海北部近海竹荚鱼资源密度的概率分布型特征

竹荚鱼(Trachurusjaponicus)是中国南海北部近海主要渔获物之一,其空间分布具有非均匀性。根据2014—2017年南海北部近海两个周期(2014—2015年为第1周期, 2016—2017年为第2周期)的底拖网调查数据,以单位捕捞努力量(catchperuniteffort,CPUE)表征资源密度,采用柯尔莫可洛夫-斯米洛夫检验(Kolmogorov-Smirnov,K-S test)探索了11种概率分布特征。结果表明,南海北部陆架区竹荚鱼不具明显的概率分布特征,而北部湾海域竹荚鱼资源密度服从对数正态分布型且第二周期较第一周期更为显著。同时,采用基于对数正态理论模型法(对数正态模型与Delta模型)与调查设计法(均值法)对该海域进行资源密度估值比较,发现基于对数正态理论模型更切合竹荚鱼资源密度结构分布特征,而在对数正态理论模型中Delta模型法更适用于该物种资源密度估值。

The probability distribution of the jack mackerel (Trachurus japonicus) density in the offshore of the northern South China Sea

The jack mackerel (Trachurus japonicus) is one of the main catches in the northern South China Sea, and its spatial distribution is non-uniform. According to the two cycles of bottom trawl survey data in the northern South China Sea from 2014 to 2017 (2014-2015 is the first cycle, 2016-2017 is the second cycle), resource density is characterized by the catch per unit effort (CPUE). The Kolmogorov-Smirnov test (K-S test) was used to explore 11 probability distribution features. The results showed that the continental shelf area of the northern South China Sea had no obvious probability distribution, while the jack mackerel resource density in the Beibu Gulf obeys the lognormal distribution pattern, and the second cycle is more significant than the first cycle. At the same time, using a lognormal theory model (lognormal model and delta model) and an investigative design method (arithmetic method) to compare the estimation of the resource density within a certain area, we found that the lognormal model is more fit to describe the distribution characteristics of the density structure of jack mackerel, and the delta model is more suitable to estimate the jack mackerel resource density.