Community structure and biogeography of shore fishes in the Gulf of Aqaba,Red Sea

Shore fish community structure off the Jordanian Red Sea coast was determined on fringing coral reefs and in a seagrass-dominated bay at 6 m and 12 m depths. A total of 198 fish species belonging to 121 genera and 43 families was recorded. Labridae and Pomacentridae dominated the ichthyofauna in terms of species richness and Pomacentridae were most abundant. Neither diversity nor species richness was correlated to depth. The abundance of fishes was higher at the deep reef slope, due to schooling planktivorous fishes. At 12 m depth abundance of fishes at the seagrass-dominated site was higher than on the coral reefs. Multivariate analysis demonstrated a strong influence on the fish assemblages by depth and benthic habitat. Fish species richness was positively correlated with hard substrate cover and habitat diversity. Abundance of corallivores was positively linked with live hard coral cover. The assemblages of fishes were different on the shallow reef slope, deep reef slope and seagrass meadows. An analysis of the fish fauna showed that the Gulf of Aqaba harbours a higher species richness than previously reported. The comparison with fish communities on other reefs around the Arabian Peninsula and Indian Ocean supported the recognition of an Arabian subprovince within the Indian Ocean. The affinity of the Arabian Gulf ichthyofauna to the Red Sea is not clear. Received in revised form: 2 November 2001 Electronic Publication     

胶州湾海域鱼类群落种类组成及多样性

为了解胶州湾海域鱼类群落结构特征,根据2016—2017年间对胶州湾海域进行的4个航次底拖网调查数据,采用相对重要性指数、生态多样性指数和典范对应分析(canonical correspondence analysis,CCA)、非线性多维标度排序(non-metric multidimensional scaling,NMDS)等方法分析了胶州湾海域鱼类群落的种类组成和多样性特征。结果表明:调查共采集到鱼类46种,隶属2纲10目30科41属,以硬骨鱼纲鱼类为主(45种,97.83%)。其中,鲈形目(Perciformes)最多(22种,47.83%),其次是鲉形目(Scorpaeniformes),占15.22%。种类数季节变化明显,以夏季最高,23种;秋季最低,16种。优势种组成以赤鼻棱鳀(Thryssa kammalensis)、褐菖鲉(Sebastiscus marmoratus)、褐牙鲆(Paralichthys olivaceus)、大泷六线鱼(Hexagrammos otakii)、许氏平鮋(Sebastes schlegeli)和矛尾鰕虎鱼(Chaeturichthys stigmatias)等鱼类为主。多样性分析显示,鱼类物种多样性存在明显的季节差异。多样性指数(H′)季节变化范围为1.668—2.453,以夏季最高,春季最低;均匀度指数(J′)季节变化范围为0.577—0.808,以秋季最高,春季最低;丰富度指数(D′)季节变化范围为2.431—3.123,以冬季最高,秋季最低。典范对应分析表明,水温、盐度、水深和pH是影响胶州湾海域鱼类群落物种组成的主要环境因子,且水温和pH是影响鱼类群落结构及多样性时空变化的主要因子。与历史调查资料相比,由于人类活动对胶州湾生态系统的干扰,鱼类群落结构发生了较大变化,优势种组成更替明显,多样性水平降低,鱼类群落结构趋向简单化。     

东海大陆架鱼类群落的空间结构

根据1997～2000年东海大陆架水深30～200米海域4个航次的底拖网调查资料,运用多元分析(聚类分析和非度量多维标度(NMDS))、SIMPER以及BIO-ENV方法分析了东海鱼类群落的空间格局以及与非生物环境因子之间的关系。结果表明,东海大陆架海域鱼类群落在空间上可分为3个群落类型,分别为东海近海群落、东海大陆架外缘群落以及这两个群落之间的东海大陆架混合群落。东海大陆架鱼类群落的种类组成沿着水深梯度的变化明显,每种鱼类均有一定的水深范围。不同的流系具有不同的温盐特征,影响了鱼类的分布及其洄游,从而控制了不同鱼类群落类型的种类组成。东海大陆架鱼类群落类型中,大陆架外缘群落类型各调查季节在空间分布和种类组成上相对稳定,而东海近海群落类型和东海大陆架混合群落类型在夏季融合在一起,其它季节保持各自的空间结构。同时东海陆架区只在一种群落类型中出现的鱼类相对较少,多数鱼类同时出现在两个群落类型中或3个群落类型中,但是它们相对较集中的区域明显不同,在不同群落类型中的生物量和出现频率有很大的差异,这些鱼类在其不同的生长发育阶段由于对海洋环境的不同需求,它们根据繁殖或摄食需求而在东海陆架区范围内洄游以寻找最适的海洋环境,因此对3个群落类型定义是相对的,很难严格确定一个永久的鱼类群落地理区域,以形成相互隔离的鱼类群落,而且鱼类群落之间的边界随着季节不同发生变化。     

长山列岛邻近海域鱼类群落种类组成和多样性时空变化

为了解黄、渤海生态系统交错带长山列岛邻近水域鱼类群落种类组成和多样性,根据2016年10月,2017年1月、5月及8月进行的鱼类资源底拖网调查数据,应用相对重要性指数、物种多样性指数、k优势度曲线等方法,研究了长山列岛邻近海域鱼类群落种类组成、物种多样性时空变化及其与环境因子的关系。结果表明: 该海域共计捕获鱼类77种,以温水性、底层、洄游性鱼类为主,优势种组成季节变化明显,春季、冬季主要优势种为黄鮟鱇,夏季以日本鲭、鳀等中上层鱼类为主。全年共计出现洄游性鱼类46种,季节间物种迁移指数均在100以上,其中秋季物种迁移指数最大。鱼类群落物种丰富度指数在春季最高、Shannon多样性指数和均匀度指数在秋季最高。夏季物种丰富度指数与表层水温呈显著负相关;冬季物种丰富度指数与水深、底层水温呈极显著正相关,Shannon多样性指数与底层水温呈极显著正相关。长山列岛邻近海域作为黄、渤海两大生态系统的交错带,鱼类群落表现出高物种多样性、洄游种多以及明显的时空异质性。     

An Analysis of Artificial Reef Fish Community Structure along the Northwestern Gulf of Mexico Shelf: Potential Impacts of “Rigs-to-Reefs” Programs

Artificial structures are the dominant complex marine habitat type along the northwestern Gulf of Mexico (GOM) shelf. These habitats can consist of a variety of materials, but in this region are primarily comprised of active and reefed oil and gas platforms. Despite being established for several decades, the fish communities inhabiting these structures remain poorly investigated. Between 2012 and 2013 we assessed fish communities at 15 sites using remotely operated vehicles (ROVs). Fish assemblages were quantified from standing platforms and an array of artificial reef types (Liberty Ships and partially removed or toppled platforms) distributed over the Texas continental shelf. The depth gradient covered by the surveys (30–84 m) and variability in structure density and relief also permitted analyses of the effects of these characteristics on fish richness, diversity, and assemblage composition. ROVs captured a variety of species inhabiting these reefs from large transient piscivores to small herbivorous reef fishes. While structure type and relief were shown to influence species richness and community structure, major trends in species composition were largely explained by the bottom depth where these structures occurred. We observed a shift in fish communities and relatively high diversity at approximately 60 m bottom depth, confirming trends observed in previous studies of standing platforms. This depth was also correlated with some of the largest Red Snapper captured on supplementary vertical longline surveys. Our work indicates that managers of artificial reefing programs (e.g., Rigs-to-Reefs) in the GOM should carefully consider the ambient environmental conditions when designing reef sites. For the Texas continental shelf, reefing materials at a 50–60 m bottom depth can serve a dual purpose of enhancing diving experiences and providing the best potential habitat for relatively large Red Snapper.     

Dominance determines fish community biomass in a temperate seagrass ecosystem

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combine surveys of natural fish communities (conducted in July and August 2016) with morphological trait data to examine relationships between biodiversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54°N, 130°W). We employ both taxonomic and functional trait measures of diversity to investigate whether ecosystem function is best predicted by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we find that fish community biomass is maximized when taxonomic richness and functional evenness are low, and in communities dominated by species with particular trait values, specifically those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is often positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.     

Fish functional diversity as an indicator of resilience to industrial fishing in Patagonia Argentina

The relationship between fish functional diversity and fishing levels at which its baselines shift is important to identify the consequences of fishing in ecosystem functioning. For the first time, the authors of this study implemented a trait-based approach in the Argentine Patagonian Sea to identify the vulnerability and spatiotemporal changes in functional diversity of fish assemblages incidentally captured by a trawling fleet targeting the Argentine red shrimp Pleoticus muelleri (Spence Bate, 1888) between 2003 and 2014. The authors coupled seven fish trophic traits to a reconstructed fish assemblage for the study area and by-catch and evaluated changes in fish species richness and four complementary functional diversity measures (functional richness, redundancy, dispersion and community trait values) along with fishing intensity, temporal use, latitudinal location and depth of fishing grounds, and vessel length. Resident fishes larger than 30 cm in length, with depressed and fusiform bodies, intermediate to high trophic levels, and feeding in benthic, demersal and midwater areas were vulnerable to by-catch. In addition, fish assemblages exhibited a low functional trait redundancy, likely related to species influxes in a biogeographic ecotone with tropicalisation signs. Significant increases in fish trait richness and dispersion poleward and deep suggested new functional roles in these grounds, matching trends in community body size, reproductive load, maximum depth and trophic level. Finally, a temporal increase in fish species and functional trait removal in fishing grounds led to trait homogenisation since 2003. The authors identified that tipping points in temperate fish functional trait diversity showed the importance of trait-based approaches within ecosystem-based fisheries management.     

Biophysical factors affecting the distribution of demersal fish around the head of a Submarine Canyon off the Bonney Coast, South Australia

We sampled the demersal fish community of the Bonney Canyon, South Australia at depths (100–1,500 m) and locations that are poorly known. Seventy-eight species of demersal fish were obtained from 12 depth-stratified trawls along, and to either side, of the central canyon axis. Distributional patterns in species richness and biomass were highly correlated. Three fish assemblage groupings, characterised by small suites of species with narrow depth distributions, were identified on the shelf, upper slope and mid slope. The assemblage groupings were largely explained by depth (ρw = 0.78). Compared to the depth gradient, canyon-related effects are weak or occur at spatial or temporal scales not sampled in this study. A conceptual physical model displayed features consistent with the depth zonational patterns in fish, and also indicated that canyon upwelling can occur. The depth zonation of the fish assemblage was associated with the depth distribution of water masses in the area. Notably, the mid-slope community (1,000 m) coincided with a layer of Antarctic Intermediate Water, the upper slope community (500 m) resided within the core of the Flinders Current, and the shelf community was located in a well-mixed layer of surface water (<450 m depth).     

Hierarchical spatial structure of stream fish colonization and extinction

Spatial variation in extinction and colonization is expected to influence community composition over time. In stream fish communities, local species richness (alpha diversity) and species turnover (beta diversity) are thought to be regulated by high extinction rates in headwater streams and high colonization rates in downstream areas. We evaluated the spatiotemporal structure of fish communities in streams originally surveyed by Burton and Odum 1945 (Ecology 26: 182–194) in Virginia, USA and explored the effects of species traits on extinction and colonization dynamics. We documented dramatic changes in fish community structure at both the site and stream scales. Of the 34 fish species observed, 20 (59%) were present in both time periods, but 11 (32%) colonized the study area and three (9%) were extirpated over time. Within streams, alpha diversity increased in two of three streams but beta diversity decreased dramatically in all streams due to fish community homogenization caused by colonization of common species and extirpation of rare species. Among streams, however, fish communities differentiated over time. Regression trees indicated that reproductive life‐history traits such as spawning mound construction, associations with mound‐building species, and high fecundity were important predictors of species persistence or colonization. Conversely, native fishes not associated with mound‐building exhibited the highest rates of extirpation from streams. Our results demonstrate that stream fish colonization and extinction dynamics exhibit hierarchical spatial structure and suggest that mound‐building fishes serve as keystone species for colonization of headwater streams.     

人为干扰对溪流鱼类功能多样性及其纵向梯度格局的影响

溪流鱼类多样性沿着河流纵向梯度的空间分布规律已得到大量报道, 但这些研究大多聚焦基于物种组成的分类α多样性, 而有关分类β多样性和功能多样性的纵向梯度分布规律及其对人类干扰的响应研究较少。本文以青弋江上游3条人为干扰程度不同的河源溪流为研究区域, 比较研究了人为干扰对溪流鱼类功能α和β多样性及其纵向梯度分布格局的影响。结果显示, 人类干扰改变了河源溪流鱼类功能多样性的纵向梯度格局——由线性变化变为二项式分布。此外, 我们发现, 人为干扰导致土著种被本地入侵种取代, 且较强的土地利用和水污染排放可能增大环境的不连续性, 而群落周转和嵌套变化往往取决于环境的变化。尽管功能β多样性由嵌套成分主导, 但周转成分占比相对于人为干扰较小的溪流而言明显增加。人为干扰显著改变了受干扰溪流鱼类的物种组成和功能多样性, 且功能多样性的纵向梯度格局在不同的多样性指标上存在差异。本研究强调, 在评估人为干扰下多样性的变化时, 需要从多方面考虑, 包括空间尺度和多样性指标等。     

Evaluating functional diversity conservation for freshwater fishes resulting from terrestrial protected areas

相似文献   

Habitat specialization in tropical continental shelf demersal fish assemblages

The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304) collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1-10 m depth), down the fore reef slope to the reef base (10-30 m depth) then across the adjacent continental shelf (30-110 m depth). Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased. The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category) were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of connected habitats through which fish can migrate.     

Macroecology of a host-parasite relationship

The larvae of freshwater mussels are obligate ectoparasites on fishes while adults are sedentary and benthic. Dispersal of mussels is dependent on the movement of fish hosts, a regional process, but growth and reproduction should be governed by local processes. Thus, mussel assemblage attributes should be predictable from the regional distribution and abundance of fishes. At a broad spatial scale in the Red River drainage, USA, mussel species richness and fish species richness were positively associated; maximum mussel richness was limited by fish richness, but was variable beneath that constraint. Measured environmental variables and the associated local fish assemblages each significantly accounted for the regional variation in mussel assemblages. Furthermore, mussel assemblages showed strong spatial autocorrelation. Variation partitioning revealed that pure fish effects accounted for 15.4% of the variation in mussel assemblages; pure spatial and environmental effects accounted for 16.1% and 7.8%, respectively. Shared variation among fish, space and environmental variables totaled 40%. Of this shared variation, 36.8% was associated with the fish matrix. Thus, the variation in mussel assemblages that was associated with the distribution and abundance of fishes was substantial (> 50%), indicating that fish community structure is an important determinant of mussel community structure. Although animals commonly disperse plants and, thus, influence the structure of plant communities, our results show a strong macroecological association between two disparate animal groups with one strongly affecting the assemblage structure of the other.     

Three ecological factors influencing riverine fish diversity in the Shubuto River system,Japan: habitat capacity,habitat heterogeneity and immigration

A major goal of stream ecology is to identify environmental gradients that shape riverine communities. We examined the relative importance of three ecological factors that have been hypothesized to influence a longitudinal pattern of fish diversity: habitat capacity, heterogeneity and immigration of diadromous fishes. Field surveys were carried out in the entire network of the Shubuto River system, Hokkaido, Japan. A hierarchical partitioning approach revealed that distance from the sea, a proxy for immigration potential of diadromous fishes, had the greatest explanatory capacity, by which 24.9 % of variation in fish species richness was explained. Habitat capacity (approximated by catchment area) was also identified as a significant predictor of fish diversity, whereas habitat heterogeneity brought little improvement to the model performance. These results reflect the fish fauna of the Shubuto River system, in which diadromous fishes are dominant in both abundance and species richness.     

嘉陵江中游蓬安段鱼类群落功能多样性研究

研究调查了蓬安段2014—2019年洪水期 (6、7和8月)和枯水期 (11、12和1月)渔获物, 用11项鱼类功能性状类型结合蓬安段鱼类群落结构特点来分析该江段鱼类群落功能多样性在洪、枯期上的变化及与水环境的关系。研究结果表明, (1)2014—2019年洪水期的物种丰富度指数、辛普森多样性指数、Pielou均匀度指数和香浓威纳指数均高于枯水期; (2)SIMPER分析显示, 大鳍鳠Mystus macropterus、子陵吻鰕虎鱼Ctenogobius giurinus、似鳊Pseudobrama simoni、黄颡鱼Pelteobagrus fulvidraco、鳜Siniperca chuatsi、蛇 Saurogobio dabryi、飘鱼Pseudolaubuca sinensis、鲫Carassius auratus、黄尾鲴Xenocypris davidi和? Hemiculter leucisculus是造成洪水期与枯水期鱼类群落结构变化的主要差异贡献种; (3)各年份洪水期的功能丰富度FRic、功能离散度FDiv、功能散布度FDis和二次熵指数Rao及2015、2016和2017年的功能均匀度指数FEve均显著高于枯水期(P<0.05), 表明枯水期鱼群落的抵抗力稳定性和恢复力稳定性显著低于洪水期, 即枯水期水生生态系统功能较脆弱; (4)鱼类群落功能多样性与水环境因子存在显著相关关系, 但不同时期的功能多样性指数与环境因子相关性程度则呈现较大差异, 表明功能多样性是鱼类群落结构和各水环境因子综合作用的结果。     

Diversity,Abundance and Community Structure of Benthic Macro- and Megafauna on the Beaufort Shelf and Slope

Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009–2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf ( 100 m) where they tended to be sparse and the slope where they were relatively abundant. The macrofauna principally comprised polychaetes with nephtyid polychaetes dominant on the shelf and maldanid polychaetes (up to 92% in relative abundance/station) dominant on the slope. The megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station) dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness ( diversity) and diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and diversity was explained by confounding factors: location (east-west), sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal diversity across the depth gradient.     

Patterns in the distribution of freshwater fishes in rivers of Central Western Ghats, India and their associations with environmental gradients

The community ecology of freshwater fishes in four river systems (Sharavati, Aghanashini, Bedti and Kali) of the central Western Ghats (India) has been studied for the first time. Patterns of fish species distributions were analysed and important stream and environmental parameters determining the species richness and composition of this region were identified. Upstream--downstream trends in species richness and diversity as well as changes in stream characteristics were studied using univariate correlation analyses. Preliminary analyses on changes in species composition and feeding guilds showed the presence of a gradual species turnover along the stream gradient. There were associated changes in the major feeding guild compositions, with a higher proportion of insectivore and algivore/herbivore composition in the upper reaches shifting to a predominance of omnivores and carnivores downstream. Pearsons product--moment correlation analyses along with stepwise multiple regression analyses identified stream depth and altitude as the important parameters determining species richness. Canonical correspondence analysis was performed to study species associations with environmental parameters. The analysis showed a strong species environmental correlation to the CCA axes, a high significance for the CCA axis 1 as well as for the overall test. The plots of the species and site scores on the CCA axes showed a clear segregation of species based on their relations with environmental and stream properties. This study is an important step in our understanding of the community structure of fish species of these rivers and would be helpful in future efforts on the conservation of aquatic communities and their habitats.     

基于环境DNA宏条形码技术的北京地区鱼类多样性调查和外来鱼种入侵风险评估

[目的]调查北京地区鱼类多样性和群落分布及评估外来鱼种的入侵风险.[方法]选取北京地区水库、湖泊和河流3种水体类型共33个采样点,于2020年6月10—17日开展水生态监测,利用环境DNA宏条形码技术对各样点的鱼类多样性和群落结构进行监测和分析,对目前北京地区水生态系统中本地鱼种和外来鱼种进行分类汇总,并评估典型外来入...     

Community structure of deep-sea demersal fish in the North Aegean Sea (northeastern Mediterranean)

The spatial structure and seasonal changes of the demersal fish assemblages on the continental shelf (100–200 m) and upper slope (200–500 m) in the North Aegean Sea (Northern Aegean and Thracian Seas, northeastern Mediterranean, Greece) were analysed. Seasonal experimental trawl surveys, carried out from summer 1990 to autumn 1993, provided a total of 151 demersal fish species. Analysis of 259 bottom trawls showed the existence of four groups associated with the continental shelf and the upper slope; each group was dominated by a small number of species. The bathymetric distribution of the species, established using measures of the centre of gravity and habitat width, revealed that most of the species had a wide distributional range within the study area, although a few were restricted to the greatest depths. Density, biomass, species richness and diversity decreased significantly with depth, and were also indicative of distinctive characteristics between these fish assemblages. Mean fish weight exhibited two different trends: a bigger-deeper phenomenon at the continental shelf and a smaller-deeper phenomenon at the upper slope. The variability in assemblage structure was determined mainly by depth and, to a lesser extent, by season and geographical location. For some species, results suggest a pattern of gradual species replacement along the depth gradient coupled with ontogenetic habitat shifts.