摘要
近海游泳动物的调查可以丰富生物多样性数据库,摸清渔业资源现状及变化趋势,并为当地渔业的有效管理提供基础数据支撑。为了解闽东近海游泳动物种类组成、密度及群落结构等特征,本研究于2021年春季(4月)和秋季(10月)在该海域布设8个站位进行游泳动物底拖网调查,应用相对重要性指数(index of relative importance,IRI)、多样性指数、数量生物量比较曲线(abundance biomass comparison curve,简称ABC曲线)、非度量多维标度(non-metric multidimensional scaling,NMDS)、相似性百分比分析(similarity percentage analysis,SIMPER)及生物-环境变量相关性(biota-environment matching,BIOENV)等方法,分析了游泳动物的物种多样性及群落特征。结果显示两个季度共捕获游泳动物147种,春季优势种表现出小型低值的特点,而秋季优势种则以经济价值较高的种类为主,其中龙头鱼(Harpadon nehereus)是唯一一种在春秋两季均占优势的种类(IRI>4,000)。春季的游泳动物物种数显著低于秋季(P<0.05)。基于质量计算的Shannon-Wiener多样性指数(H’BW)在春季显著低于秋季(P<0.05),且春季游泳动物种间亲缘关系较近,平均分类差异指数较低。游泳动物密度中,春季平均尾数密度和平均质量密度分别为16.9×10^(3)±14.5×10^(3)ind./km^(2)和474.0±362.0 kg/km^(2),极显著低于秋季的240.8×10^(3)±178.6×10^(3)ind./km^(2)和2,587.5±1,495.5 kg/km^(2)(P<0.01)。春季鱼类幼体尾数比例极显著低于秋季(P<0.01)。ABC曲线表明,游泳动物群落受到中等甚至严重干扰,且秋季尤为严重。游泳动物群落结构表现出极显著的春秋季差异(P<0.01),与群落结构相关性最高的环境因子组合为温度和溶解氧(r=0.548,P<0.01)。本研究揭示了闽东近海游泳动物平均质量密度在经历2017年低值后目前恢复到2007年的水平。春秋季调查分别在伏季休渔期前后开展,如果能做到长期和持续的跟踪调查,可以为今后休渔期成效的评估提供依据。
Aim:Nekton surveys in coastal waters can enrich our understanding of species diversity,assess the status of local fishery resources and variations in their trends,and provide the fundamental data that needed for effective management.The aim of this study was to understand nekton species composition,density,and community structure in coastal waters of eastern Fujian Province.Methods:Bottom trawl surveys were conducted at eight stations in coastal waters of eastern Fujian Province to collect nekton samples in spring(April)and autumn(October)of 2021.Fishes,crustaceans and cephalopods were identified to species level if possible.The index of relative importance(IRI),Shannon-Wiener diversity index based on number(H'N)and weight(H'BW),taxonomic diversity indices(taxonomic diversity,Δ;taxonomic distinctness,Δ*;average taxonomic distinctness,Δ+;variation in taxonomic distinctness,Λ+)and densities(i.e.abundance and biomass)were calculated.The proportions of the number of juvenile fishes were estimated based on length measurements and the lengths at fish sexual maturation were obtained from Fishbase(www.fishbase.org).Abundance biomass comparison curve(ABC curve)of nekton and different taxonomic groups(fishes,crustaceans and cephalopods)were also evaluated.Non-metric multidimensional scaling(NMDS),similarity percentage analysis(SIMPER),and biota-environment matching(BIOENV)were used to describe the characteristics of the nekton community structure and the relationships with five environmental factors(temperature,dissolved oxygen,salinity,pH and water depth).The differences in the nekton community between spring and autumn were also tested statistically.Results:A total of 147 nekton species,including 82 fishes,57 crustaceans,and 8 cephalopods,were collected.Eleven dominant species(IRI≥500)were identified,including Harpadon nehereus,which had the highest IRI values(IRI>4,000)in both spring and autumn,and was the only species that dominated in both seasons.The dominant species were generally small-sized and low-valued in spring,and large-sized and high-valued in autumn.The Shannon-Wiener diversity index based on weight(H'BW)in spring was significantly lower than that of autumn(P<0.05).The low average taxonomic distinctness(Δ+)in spring indicated that the taxonomic relationship of nekton species was closely associated.The average densities of nekton were 16.9×10^(3)±14.5×10^(3) ind./km^(2) and 474.0±362.0 kg/km^(2) in spring,which were significantly lower than those in autumn(240.8×10^(3)±178.6×10^(3) ind./km^(2) and 2,587.5±1,495.5 kg/km^(2))(P<0.01).The number of nekton species,the H'BW and the proportions of the number of juvenile fishes in spring were significantly lower than those in autumn(P<0.05).ABC curves suggested that the nekton communities in coastal waters of eastern Fujian Province were under a disturbed-even stressed-condition,especially in autumn.The nekton community structure was significantly distinct between spring and autumn(P<0.01).The community structure was closely related to the combination of temperature and dissolved oxygen factors according to the BIOENV results(r=0.548,P<0.01).Conclusion:This study revealed that the number of nekton species in coastal waters of eastern Fujian Province was relatively high,irrespective of only two seasonal surveys,compared to other coastal areas in Fujian.Based on comparisons of the average density and the average body weight of nekton in 2007-2021 in the same area or other waters of Fujian,the fishery resources in coastal waters of eastern Fujian Province showed a positive trend.As these surveys were conducted before and after the national summer fishing moratorium,long-term monitoring can be applied to evaluate the effectiveness of the fishing moratorium regulation in the future.
作者
刘彩莲
许庆
王林龙
邢衍阔
宋稼豪
林柏岸
康斌
刘敏
Cailian Liu;Qing Xu;Linlong Wang;Yankuo Xing;Jiahao Song;Baian Lin;Bin Kang;Min Liu(College of Ocean and Earth Sciences,Xiamen University,Xiamen,Fujian 361102;Fisheries College,Ocean University of China,Qingdao,Shandong 266003)
出处
《生物多样性》
CAS
CSCD
北大核心
2023年第7期111-127,共17页
Biodiversity Science
基金
国家自然科学基金(41976091)。
关键词
福建海域
游泳动物
群落结构
多样性
密度
伏季休渔
Fujian waters
nekton
community structure
diversity
density
summer fishing moratorium