南沙群岛中北部重要岛礁鱼类资源调查

1998年4月和1999年5月,采用手钓、延绳钓和流刺网作业在南沙群岛的渚碧、南薰、东门、美济、赤瓜、永署和华阳等7座珊瑚礁水域进行了2个航次的鱼类资源调查。累计投入的捕捞努力量分别为手钓357钩·时、延绳钓4220钩、流刺网19750m,单次作业努力量手钓6～18钩·时、延绳钓40～480钩、流刺网40～2400m。捕获鱼类180种,渔获量1860尾1540.4kg,其中手钓102种1225尾196.8kg,延绳钓36种82尾1234.7kg,流刺网70种553尾108.9kg。按岛礁平均,渔获率和单位捕捞努力量渔获量(CPUE)手钓为351.1尾·(100钩·时)-1、51.9kg(100钩·时)-1,延绳钓为2.6尾·(100钩)-1、39.0kg·(100钩)-1,流刺网为51.4尾·(1000m)-1、7.5kg·(1000m)-1。礁坪区流刺网的渔获率和CPUE为170.3尾·(1000m)-1、23.1kg·(1000m)-1,均高于礁缘浅水区和礁缘深海区。捕获的主要经济种类有鲨鱼、裸胸鳝、石斑鱼、笛鲷、裸颊鲷、鹦嘴鱼和隆头鱼科鱼类等。华阳和永暑礁鱼类资源比较丰富,具有较高的开发潜力;东门、美济和南薰礁次之,也有一定的生产价值;赤瓜和渚碧礁基本没有开发价值。     

南沙群岛礁盘手钩钓活鱼试验报告

我国南沙群岛远离祖国大陆，处于热带区域，岛、礁、洲230多座。其礁岛生态环境独特，生物种类多样。而且水质不受任何污染影响，南沙群岛水生生物具有高品位商品经济价值，如绘科、后科、衡钢利、龙虾等种类。珊瑚礁盘浅水域生物群体小、生物量低，难以提供为规模性的渔业开发利用。为探索一种既可合理利用经济鱼类资源，获取良好的经济效益，又保护好生态环境以持续性发展的捕捞手段，我们于1999年3月8日～5月12日首次组织海南省琼海市渔民的一艘刺网渔船，以单艇手钓作业方式，进行一个航次的钩钓活鱼捕捞及活鱼保存的试验（试验期间，渔…     

西沙群岛重要珊瑚礁海域鱼类区系

根据1998年5月、1999年5月和2003年5月在西沙群岛北礁、永兴岛、琛航岛、华光礁、浪花礁、金银岛、东岛和玉琢礁等8个岛礁的调查资料,研究了西沙群岛岛礁水域的鱼类区系。在8个岛礁共捕获鱼类48科261种,其中礁栖性鱼类占78.93%,在8个岛礁广泛分布的鱼类只有33种,各礁区之间种类的相似度不超过41%,因此,种类多样性高和相似度低是该区域鱼类区系的2个主要特征。与南沙岛礁(1998～1999)延绳钓、刺网和手钓以及南沙群岛西南陆架区(1991)、南海北部海域等底拖网鱼类相比较,物种相似度分别为34.0%、5.1%和6.8%。     

南海主要珊瑚礁(鱼旨)科鱼类的组成与分布

1998年3~5月和1999年5~6月,采用手钓、延绳钓和刺网3种作业方式在西沙的浪花礁、华光礁、琛航岛、永兴岛、北礁和南沙的渚碧礁、南薰礁、东门礁、美济礁、赤瓜礁、永署礁、华阳礁等12座珊瑚礁水域进行了2个航次的鱼类资源调查,捕获科鱼类6属25种,渔获量计942尾256.4kg;其中在南沙调查区捕获6属22种,共641尾205.5kg,优势种依次为尾纹九棘鲈、蜂巢石斑鱼、六角石斑鱼、黑边石斑鱼;在西沙调查区捕获6属14种,共301尾50.9kg,优势种依次为尾纹九棘鲈、六角石斑鱼、黑边石斑鱼、蜂巢石斑鱼,同时分析了主要种类尾纹九棘鲈、六角石斑鱼和蜂巢石斑鱼的生物学特征。     

南海美济礁瀉湖区鱼类优势种和生物多样性的长期变化

珊瑚礁鱼类是诊断和修复退化珊瑚礁新方法的关键组分。为了解环境变化和人类活动胁迫下南海典型珊瑚礁鱼类组成和多样性的演变趋势, 本研究根据 1998—2018 年美济礁瀉湖区鱼类手钓和刺网调查数据, 对南海美济礁瀉湖区鱼类种类组成、优势种和物种多样性指数的长期变动进行研究。结果表明, 与 1998—1999 年相比, 2012— 2018 年美济礁瀉湖区鱼类组成和优势种更替明显, 鹦嘴鱼科(Scaridae)、刺尾鱼科(Acanthuridae)、蓝子鱼科(Siganidae) 等具有重要生态功能的鱼类消失或明显减少; 优势种数目下降, 但其优势度显著增加, 第 1 优势种的相对优势度和所有优势种的平均优势度均明显增加; 1998—2018 年采集单位鱼类种类数所需的捕捞努力量和样本量均明显稳定增加; 手钓努力量增加对相应物种多样性指数增加有明显影响, 刺网努力量增加对多样性指数增加影响不明显; 刺网采样方式评估美济礁鱼类物种多样性比手钓采样方式更稳健; 基于刺网鱼类样本, 与 1999 年 5 月相比, 2016— 2018 年美济礁瀉湖区鱼类物种多样性极显著降低。结论认为, 人类捕捞和美济礁有效生境面积下降而导致的生态系统承载力下降是鱼类种类或丰度减少及多样性降低的主要原因。为促进南海美济礁鱼类资源恢复和保护, 建议及时采取措施保护其资源, 改善栖息地质量。     

南沙群岛礁盘区手钩钓鱼及保活试验

选用木质刺网渔船一艘，以单艇手钓作业方式，在南沙群岛礁盘区域进行为期５４天（一个航次）的手钩钓鱼及活鱼保存试验。钓捕结果表明，南沙群岛礁盘区域经济鱼类种类较多，钓获量大，手钓作业的经济效益及生态效益显著，是值得推广的一种捕鱼生产方式。     

中沙、南沙群岛礁盘深水域中下层鱼类资源开发利用技术研究

我国中沙、南沙群岛礁盘众多，海域广阔，渔业资源丰富，是刺网和钓钩深水捕捞作业的理想渔场。近三年来，海南省琼海市渔民应用定置刺网渔具探捕了中沙、南沙群岛礁盘60－140米深中下层水域鱼类资源状况，获取第一手资料。经初步整理分析结果，本文报告此水域中下层鱼类种类组成及资源状况，共记录了鱼类种类有116种，分隶于13目30科属和甲壳类3种。渔获物总上网率为63.81kg／1000m，其中，软骨鱼类为51．00kg／100m，硬骨鱼类为1280kg／1000m。不同网目大小的三种定置刺网，以大网目三层定置利网的渔获量最佳，渔获率为94．23kg/1000m，捕…     

海南岛东岸、南岸浅水礁区近10年珊瑚礁鱼类种类分布及多样性探讨

根据2004—2013年海南岛东岸、南岸浅水礁区珊瑚礁鱼类监控数据,利用截线样条法、分类学多样性指数、相对丰富度及相似性指数等方法技术对海南岛东岸、南岸浅水礁区珊瑚礁鱼类种类组成及生物多样性进行研究。结果显示,海南东岸、南岸浅水礁区近10年调查珊瑚礁鱼类共计6目32 科64属130种,其中鲈形目居绝对优势;珊瑚礁鱼类密度大致呈现由南向北逐渐递减的趋势;科级多样性平均值为4.41,属级多样性指数平均值为3.09,标准化的G-F指数平均值为0.30;鲈形目珊瑚礁鱼类相对丰富度占有绝对优势,相对丰富度较高的6个科分别为雀鲷科、隆头鱼科、蝴蝶鱼科、天竺鲷科、四齿鲀科及玻甲鱼科;珊瑚礁鱼类在目级极为相似,相似性指数在0.86～1之间;科、属、种级相似性指数较低,均在0.5以下,通过Jaccard's种类相似性指数分析,海南岛东岸、南岸珊瑚礁鱼类种类较多,物种丰富。珊瑚礁鱼体长范围6～10 cm区间的数量最多,其次为0 ～5 cm区间,21～40 cm区间的珊瑚礁鱼类在浅水礁区分布极少。本研究通过对海南岛东岸、南岸浅水礁区珊瑚礁鱼类近10 a的种类分布及多样性进行探讨,旨在为海南岛珊瑚礁生态系统及珊瑚礁鱼类保护与研究提供基础数据及理论依据。     

我国渔船捕捞装备的发展方向与重点

捕捞装备主要是围绕渔船作业方式来匹配的。目前国内渔船的作业主要是：拖网、围网、流网、张网、延绳钓、鱿钓等作业方式。拖网以底拖网为主，围网以中小型围网为主，流网和张网以群众性渔船为主，延绳钓以金枪鱼延绳钓和延绳笼为主，鱿钓主要以远洋作业为主。其中大型流刺网和底拖网对渔业资源的破坏较严重，应限制数量或逐渐淘汰。     

枸杞岛近岸3种生境鱼类群落组成及岩礁区底栖海藻对鱼类群落结构的影响

2005年—2006年及2010年5—6月对枸杞岛近岸岩礁生境分布的底栖海藻进行观测和潜水采样,发现岩礁生境潮下带底栖海藻组成模式分以大型底栖海藻铜藻为优势种和以孔石莼等小型藻类为优势种两类。2009年2月—2010年1月利用组合刺网对枸杞岛海域岩礁、沙地和贻贝筏式养殖区3种生境的鱼类进行了逐月采样,通过采用方差分析、聚类和非度量多维标度等统计分析手段发现:(1) 岩礁生境鱼类以底栖趋礁杂食性为主,沙地生境鱼类以中下层洄游肉食性为主,贻贝筏式养殖区生境鱼类大型个体占优;(2) 岩礁生境鱼类多样性较高,大型底栖海藻生长的岩礁生境中鱼类群落组成较小型底栖海藻生长的岩礁生境稳定。前者为枸杞岛近岸优势种群繁衍提供有利条件,对鱼类幼体和小型个体有诱集作用,为鱼类捕食者提供更多样化的食物选择,鱼类群落较稳定;后者易受外界鱼类迁移的影响,个体数量和生物量月间差异大。     

A role for partially protected areas on coral reefs: maintaining fish diversity?

• 1. Completely banning fishing from coral reefs is now accepted to have significant benefits for marine biodiversity and in many cases, fisheries. However, the benefits of regulating fishing on coral reefs, by restricting the methods used, or the total amount of fishing, are less well understood, even though such regulations are much more likely to be supported by fishermen.
• 2. This study assesses whether banning illegal, destructive fishing methods and reducing the numbers of fishermen visiting from outside an area benefits a coral reef fishery, despite unregulated fishing by local fishermen using non‐destructive methods.
• 3. The abundance, biomass, mean length, and species richness of nine commercially important fish families are compared across ten independent patch reefs inside and outside the 470 km² Menai Bay Conservation Area in Zanzibar, Tanzania.
• 4. Even after taking into account the effect of differences in habitat and the distance between reefs, 61% (±19.7%) more fish species were found in regulated than unregulated reefs. Fish abundance, biomass, and length were not affected, suggesting that banning destructive fishing may improve biodiversity, but that further regulations may be required to improve fish stocks.Copyright © 2011 John Wiley & Sons, Ltd.

     

Fish stock assessment of the northern New Caledonian lagoons:1 – Structure and stocks of coral reef fish communities

Lagoon fish in New Caledonia are mainly caught by artisanal fisheries and subsistence fishing. Reef fish are the major component of this catch. The present study aimed at estimating these reef fish standing stocks and at finding the main factors influencing the distribution of these fish. Sampling of 904 stations was stratified according to three zones (north, east and west) and three reef types (barrier, intermediate and fringing). Fish communities exhibited strong heterogeneity in their distribution, showing higher biomass (maximum of 447 g·m^–2) and total standing stock (43 000 tonnes) in the north zone than in the east and west zones. Similarly, observed patterns were dependent on reef types: higher biomass and total standing stock being observed on barrier reefs than on intermediate or fringing reefs. The total standing stocks, which were about 65 000 t, were mainly composed of herbivorous fish families such as the Acanthuridae and Scaridae. The differences in the patterns of distribution of species, individuals and standing stocks between reef types may be explained by variations in terrestrial influences and reef morphology, whereas differences among zones were most likely due to accessibility of fishing areas and fishing pressure. The latter is almost non-existent in the north zone, which can thus be considered to be almost unexploited commercially. This most likely explains the high proportion, 77 %, of long-lived species in the biomass of this zone. The results might have implications in management of reefs elsewhere in the South Pacific, for which similar data are only scarcely available.     

Relative importance of habitat and fishing in influencing reef fish communities across seventeen Pacific Island Countries and Territories

Reef fish assessments were undertaken in 17 Pacific islands to describe the status of finfish resources in 63 villages where fishing is mainly artisanal. Surveys were performed by recording the number and size of edible fish species and benthic composition. Fishing impact was described through six proxies representing level of catch, alternative incomes, degree of commercial catch and country economic development derived from a simultaneous socioeconomic assessment. The relative importance of broadly defined habitat (geographical location, island and reef type, substrate composition) and fishing impact in controlling the distribution of fish trophic groups, families and species was measured through multivariate analysis. The extreme faunistic diversity was shown by the large variation in fish density (difference of up to an order of magnitude) and fish biomass (displaying a 20‐fold difference across the region). Herbivores were dominant in the eastern part of the region, at what we classified as complex islands and at islands with small lagoon and at coastal reefs, while carnivores were dominant at oceanic islands and atolls and at outer reefs. Specific habitat associations were shown for Scaridae, Acanthuridae, Siganidae, Balistidae, Lethrinidae, Lutjanidae and Serranidae. Relative importance and size decrease of several fish families (Mullidae, Scaridae, Lutjanidae and Serranidae) were related to high fishing impact. Acanthuridae and Lethrinidae appeared to have a role as opportunistic groups in impacted sites. The relative impact from fishing and habitat on fishes accounted for, respectively, 20 and 30% of variance, demonstrating the effect of human impacts even at such large scale and taking into account only limited fishing impact variables.     

南沙群岛重点岛礁潟湖微型浮游动物的群落结构与摄食

潟湖是岛礁生物多样性演变的重要环境场,在岛礁水生态系统的物质循环和能量流动中发挥重要作用,而微型浮游动物的生态功能研究是解析南沙群岛岛礁水域潟湖生态系统初级生产力组成、流向、能量流动效率的重要研究内容之一。实验通过对南沙群岛重点岛礁渚碧礁、美济礁与永暑礁潟湖表层水域中微型浮游动物与生态环境调查,研究了其群落结构及其与环境因子的关系,并通过稀释培养实验研究了微型浮游动物的摄食压力。结果显示,调查水域共发现微型浮游动物20种,总丰度的范围为320～1 460个/L,以无壳纤毛虫丰度最高。无壳纤毛虫在渚碧礁潟湖西部水域（ZB-1）丰度最高,砂壳纤毛虫峰值则出现在永暑礁潟湖中部水域（YS-3）,桡足类幼体丰度最大值出现在美济礁潟湖北部水域（MJ-2）。聚类分析结果显示,3个岛礁潟湖中部区域的微型浮游动物群落相似度较高,溶解氧是影响群落结构的最重要因素,特别是对MJ-3站位影响最为突出。摄食实验结果显示,3个岛礁潟湖水域浮游植物生长率为0.22～1.36 d^-1;微型浮游动物摄食率范围为0.22～0.60 d^-1,微型浮游动物每天约摄食浮游植物现存量的...     

Fish assemblages associated with artificial reefs of concrete aggregates or quarry stone offshore Miami Beach,Florida, USA

Few studies have compared the suitability of different artificial reef construction materials in terms of their efficacy in acquiring diverse faunal assemblages. We compared the fishes associated with 12 co-located reefs constructed of limestone quarry boulders, concrete-gravel aggregate, or concrete-tire aggregate (four of each substrate) in 7 m of water, 200 m offshore Miami Beach, Florida, USA. All 12 reefs were deployed 100 m apart the same day in two lines of six. The four quarry stone reefs consist of a pile of 50 boulders each. The remaining eight reefs, of concrete-gravel aggregate and concrete-tire aggregate, were each constructed with 25 1.5 m edge and 25 1.2 m edge tetrahedron modules. Every two months from October 1998 to February 2001, SCUBA divers recorded fish species, abundance, and length, as well as spiny lobster, Panulirus argus, abundance. One hundred and forty-six species of fishes were recorded during the study period. The abundance and species richness of fish on each treatment exhibited a significant (p<0.05) seasonal variation with summer months having the greatest numbers and winter the lowest. There was no significant difference in total fish or spiny lobster abundance or fish biomass amongst the three reef types (p>0.05). Likewise, multi-dimensional scaling of Bray-Curtis dissimilarity indices did not indicate clustering of fish assemblages by reef type. Comparison of pre-deployment fish counts from the reef sites and neighboring hard bottom and jetty with counts from the same sites two years post-deployment indicate the artificial reefs increased both fish abundance and richness in the local area.     

The effects of epibenthic communities on reef fishes in the northern Gulf of Mexico

Abstract  Reef fishes were compared between artificial reefs with ( n  =   20) and without ( n  =   20) epibenthic communities in the northern Gulf of Mexico. Artificial reefs were built in June 2003; half were coated with copper-based paint to prevent epibenthic community development. Reefs were surveyed by SCUBA divers to estimate fish abundance in the autumn and winter 2003 and spring 2004. Total fish abundance and abundance of red snapper, Lutjanus campechanus (Poey), and gray triggerfish, Balistes capriscus Gmelin, were significantly ( P  ≤   0.05) higher on reefs with epibenthic communities. In the spring 2004, the abundance of belted sandfish, Serranus subligarius (Cope), the size of red snapper and community measures of diversity and evenness were significantly ( P  ≤   0.05) greater on unpainted reefs. These significant differences provide evidence that reef fishes were positively affected by the presence of epibenthic organisms that probably provided increased food resources.     

Comparison of three standardised fish sampling methods in 14 alpine lakes in Austria

Abstract Standardised fishing methods using gillnets (EN 14575), electric fishing (EN 14011) and hydroacoustics (WI 00230244 CEN enquiry) to estimate species composition, abundance, biomass and size distribution were compared in 14 alpine lakes >50 ha. More fish species were detected using benthic gillnets (mean = 72.7%) than electric fishing (mean = 59.5%) and pelagic gillnets (mean = 29.6%). For all but two lakes, additional information from a local fisheries manager was required to obtain a complete list of species. Biomass data generated by standardised gillnetting and hydroacoustic surveys were not fully comparable, but a positive correlation was found. Gill netting and hydroacoustics both indicated a nearly fishless habitat below 75 m, which confirmed the maximum required fishing depth according to the European Standard EN 14757. Size distributions obtained from gillnet and hydroacoustic surveys differed statistically for large fish (>40 cm). Each standardised method reflected typical shortcomings. The European standard (EN 14757) should be amended for pelagic fish habitat in deep alpine lakes to include sampling effort corresponding to water volume, and additional gillnets with larger mesh sizes (e.g. 70 mm). Furthermore, the electric fishing standard (EN 14011) should be extended to incorporate requirements of lake fish sampling.     

Macroalgal meadow habitats support fish and fisheries in diverse tropical seascapes

Canopy‐forming macroalgae can construct extensive meadow habitats in tropical seascapes occupied by fishes that span a diversity of taxa, life‐history stages and ecological roles. Our synthesis assessed whether these tropical macroalgal habitats have unique fish assemblages, provide fish nurseries and support local fisheries. We also applied a meta‐analysis of independent surveys across 23 tropical reef locations in 11 countries to examine how macroalgal canopy condition is related to the abundance of macroalgal‐associated fishes. Over 627 fish species were documented in tropical macroalgal meadows, with 218 of these taxa exhibiting higher local abundance within this habitat (cf. nearby coral reef) during at least one life‐history stage. Major overlap (40%–43%) in local fish species richness among macroalgal and seagrass or coral reef habitats suggest macroalgal meadows may provide an important habitat refuge. Moreover, the prominence of juvenile fishes suggests macroalgal meadows facilitate the triphasic life cycle of many fishes occupying diverse tropical seascapes. Correlations between macroalgal canopy structure and juvenile abundance suggests macroalgal habitat condition can influence levels of replenishment in tropical fish populations, including the majority of macroalgal‐associated fishes that are targeted by commercial, subsistence or recreational fisheries. While many macroalgal‐associated fishery species are of minor commercial value, their local importance for food and livelihood security can be substantial (e.g. up to 60% of landings in Kenyan reef fisheries). Given that macroalgal canopy condition can vary substantially with sea temperature, there is a high likelihood that climate change will impact macroalgal‐associated fish and fisheries.