Parasites of recruiting coral reef fish larvae in New Caledonia

Recruiting coral reef fish larvae from 38 species and 19 families from New Caledonia were examined for parasites. We found 13 parasite species (Platyhelminthes: Monogenea, Cestoda and Trematoda) but no acanthocephalan, crustacean or nematode parasites. Over 23% of individual fish were infected. Didymozoid metacercariae were the most abundant parasites. We conclude that most of the parasites are pelagic species that become ‘lost’ once the fish larvae have recruited to the reef. Larval coral reef fish probably contribute little to the dispersal of the parasites of the adult fish so that parasite dispersal is more difficult than that of the fish themselves.     

The southwestern Atlantic reef fish fauna: composition and zoogeographic patterns

The Brazilian coast, the Caribbean and the tropical South Atlantic oceanic islands reef ichthyofauna separated into two major clusters: (1) the western Atlantic continental margin and Bermuda, further divided into (1a) the western North Atlantic, and (1b) the Brazilian coast; and (2) the South Atlantic oceanic islands, also divided in (2a) the Brazilian offshore islands, and (2b) Ascension and St Helena. Species geographic ranges suggest the recognition of only two western Atlantic zoogeographic provinces for tropical marine shore fishes. A Brazilian Province, including the offshore localities of Atol das Rocas, Fernando de Noronha, Trindade and St Paul's Rocks, and an expanded West Indian Province that includes Bermuda. Ascension and St Helena should be regarded as a separated Central Atlantic Province.     

临海东矶海域人工鱼礁大型底栖动物群落的早期发育

为养护渔业资源和修复受损海岸带生态系统,人工鱼礁通常被投放至沿岸海域的海底,为海洋生物提供新的栖息地。于2022年5月(投放后10个月)和10月(投放后15个月)调查了临海东矶人工鱼礁大型底栖动物群落,分析了不同礁龄间大型底栖动物种类组成、密度、生物量和群落结构的差异。两次调查共记录到5类17种大型底栖动物,优势种为猫爪牡蛎Talonostrea talonata和侧花海葵Anthopleura sp.。礁体投放10个月后大型底栖动物群落的平均密度和平均生物量分别为(3519±289)个/m²和(3657±273)g/m²,15个月后平均密度和平均生物量分别为(10056±1858)个/m²和(8300±2045)g/m²,15个月的密度和生物量均显著高于10个月的(P>0.05)。不同礁龄间大型底栖动物群落结构具有显著性差异(Globe R=0.573, P=0.029),导致群落结构差异的物种主要是曲膝薮枝螅Obelia genicutata、侧花海葵、褐蚶Didimarca tenebricum、丽核螺Tritonoharpa leali、双纹须蚶Barbatia bistrigata和疣荔枝螺Thais clavigera。礁体投放10个月后和15个月后人工鱼礁附着猫爪牡蛎的平均密度分别为(2075±37)个/m²和(2194±397)个/m²,不同礁龄间没有显著性差异(P>0.05)。发现临海东矶人工鱼礁表面分布有低物种丰度和高密度的大型底栖动物群落,并发育成为以猫爪牡蛎为造礁种的人工牡蛎礁。     

海洋生物礁类型、生态功能及其生态修复

海洋生物礁是由具有造礁能力的海洋生物聚集而成的一种三维礁体结构,其形成改变了海底地貌、增加了不同尺度上的地形复杂性,为其他海洋生物提供了栖息地并维持了生物多样性。近年来,由于自然因素和人为因素影响,海洋生物礁受到了严重威胁,已成为海洋生态保护和修复领域的重要研究对象。综述了海洋生物礁的类型、生态功能及其生态修复的研究进展。根据形成海洋生物礁的优势造礁生物种类,将海洋生物礁分为海藻礁、海绵礁、刺胞动物礁、贝类礁和多毛类礁,其优势造礁生物分别是珊瑚藻和仙掌藻、钙质海绵和硅质海绵、造礁珊瑚、牡蛎、龙介虫。目前国内对海洋生物礁的全面了解相对较少,主要集中在珊瑚礁和牡蛎礁。海洋生物礁的生态功能主要有海岸防护、提供栖息地、净化水体、固碳作用和能量耦合等。全球变暖和海洋酸化等全球气候变化以及海洋污染、破坏性渔业捕捞、海岸工程、水产养殖和敌害生物等自然和人为因素对海洋生物礁构成了严重威胁。海洋生物礁的生态修复方法分为两类：在退化生物礁区投放造礁生物逐渐成礁,投放人工礁体补充造礁生物逐渐成礁。针对海洋生物礁保护和修复的需要,提出下一步应加强海洋造礁生物生态特征、海洋造礁生物种群丧失因素和海洋生物礁保护与...     

大型海藻在珊瑚礁退化过程中的作用

随着全球范围珊瑚礁的退化,大型海藻在珊瑚礁区的覆盖度呈增多的趋势。大型海藻的大量生长,妨碍了珊瑚的生长、繁殖、恢复等过程。概括起来,大型海藻对珊瑚生长、繁殖及恢复过程所产生的不利影响主要包括:(1)大型海藻通过与珊瑚竞争空间和光照而影响珊瑚生长;(2)大型海藻与珊瑚直接接触时,通过摩擦作用及释放化感物质而影响珊瑚生长;(3)大型海藻的大量生长打破了珊瑚与海藻的竞争平衡,珊瑚为应对大型海藻的入侵而把用于生长和繁殖的能量转移到组织修复与防御上,进而造成珊瑚繁殖能量的减少;(4)大型海藻通过影响珊瑚幼虫的附着及附着后的存活率,而阻碍珊瑚群落的发展;(5)海藻还能通过富集沉积物、释放病原体及扰乱珊瑚共生微生物的生长等而间接影响珊瑚生长。明确的竞争机制有利于研究海藻与珊瑚的相互作用过程。在总结前人对海藻与珊瑚的竞争机制研究的基础上,把两者的竞争机制划分成物理机制、化学机制、微生物机制三大类,物理机制是研究得比较透彻的竞争机制,而化学机制与微生物机制则需要更深入的研究,是当前研究的热点。目前,我国对珊瑚礁中底栖海藻与珊瑚的相互作用研究甚少;鉴于此,对底栖海藻功能群的划分类型以及三大类型底栖海藻对珊瑚的作用特点做了简要介绍,并对珊瑚礁退化的现状和退化珊瑚礁区内海藻的表现做了概述。在此基础上,再综述国外关于大型海藻对珊瑚的影响研究进展,指出我国应该加强对南海珊瑚礁区大型海藻的种类分布及丰富度等的调查,评价大型海藻对南海珊瑚礁的影响现状;并结合生理学、分子生物学技术和生态学研究手段,在细胞与分子水平上探索海藻对珊瑚的影响机制,以期为珊瑚礁生态系统的保护提供参考。     

江苏海门蛎岈山牡蛎礁生态现状评价

基于2013—2014年间的生态调查结果,评价了江苏海门蛎岈山牡蛎礁的生态现状。无人机航拍结果显示,江苏海门蛎岈山分布有750个潮间带区牡蛎礁斑块,总面积约为201519.37 m2;与2003年相比,海门蛎岈山牡蛎礁面积约下降了38.8%。活体牡蛎的平均盖度约为66%,2013年5和9月熊本牡蛎Crassostrea sikamea的平均密度分别为(2199±363)个/m2和(2894±330)个/m2。2013年5月海门蛎岈山熊本牡蛎种群的平均肥满度(CI)和性腺指数(GI)分别为(9.76±0.95)%和(1013±82)mg/g,均显著低于浙江象山港养殖的熊本牡蛎种群(P0.05)。海门蛎岈山熊本牡蛎的单倍体多样性和核苷酸多样性指数分别为0.119和0.00028,均高于长江口野生种群和浙江象山港养殖种群。海门蛎岈山熊本牡蛎种群受到尼氏单孢子虫(Haplosporidium nelson)的轻度浸染,其感染率(17.2%)低于浙江象山港养殖群体(47.3%)。泥沙沉积和人类捕捞是江苏海门蛎岈山牡蛎礁面临的主要胁迫因子,今后牡蛎礁恢复的重点是增加附着底物的数量。     

雷州半岛灯楼角珊瑚礁的生态特征与资源可持续利用

分布于雷州半岛西南部灯楼角的珊瑚礁,自海向陆可分为6个生态带,已鉴定出现代活石珊瑚(Scleractinia) 13科2 5属39种3未定种。该珊瑚礁位于热带北缘,附近人口密集,它的发育受自然因素和人类活动双重制约。气候方面,近4 2 a来的温度总体上升有利于本区珊瑚礁的发育,而台风活动对本区珊瑚礁可能有负面的影响;人类活动对本区珊瑚礁的影响表现为旅游业的快速发展与保护行动滞后威胁珊瑚礁、渔业和养殖业影响珊瑚礁、作为建筑材料使用而破坏珊瑚礁等3个方面。作为一种重要的海洋生态资源,本区珊瑚礁若得以科学保护,将具有广阔的可持续利用前景     

Community structure and diet of roving herbivorous reef fishes in the Abrolhos Archipelago, south-western Atlantic

Community structure and diet of roving herbivorous reef fishes were analysed in 13 study sites around the five islands of the Abrolhos Archipelago, north-eastern Brazil (17°58' S; 38°42' W). This area has been part of the Abrolhos Marine National Park since 1983. Abundances and diets of fishes within the families Scaridae, Acanthuridae and Kyphosidae were compared among groups of sites differing in benthic community structure and exposure regime. The abundance of roving herbivorous fishes was higher in shallower sites than in deeper sites. At all study sites, observations of total herbivorous reef fish community structure revealed that 64% of fishes were acanthurids, 33% were scarids and only 4% were kyphosids. This pattern was predominant in all study sites. The majority of fishes examined in this study had the bulk of their diet based on both algae (35–90%) and detritus (35–65%). Among groups of algae, filamentous algae were the most commonly consumed as the majority of roving herbivorous fishes in Abrolhos feed as scrapers and excavators. The exceptions were the kyphosids, which had a diet consisting primarily of macroalgae (mainly Phaeophyta), and Acanthurus coeruleus that consumed mainly turf algae and very little detritus. The data collected indicate that roving herbivorous fishes in the Abrolhos Archipelago are more abundant at calm sites where detritus and delicate algae, their major food resources, are more abundant. The results presented here, along with underwater observations, suggest that the abundance and diet of these three fish families are associated with substratum cover.     

Environmental controls on the global distribution of shallow‐water coral reefs

Aim Elucidating the environmental limits of coral reefs is central to projecting future impacts of climate change on these ecosystems and their global distribution. Recent developments in species distribution modelling (SDM) and the availability of comprehensive global environmental datasets have provided an opportunity to reassess the environmental factors that control the distribution of coral reefs at the global scale as well as to compare the performance of different SDM techniques. Location Shallow waters world‐wide. Methods The SDM methods used were maximum entropy (Maxent) and two presence/absence methods: classification and regression trees (CART) and boosted regression trees (BRT). The predictive variables considered included sea surface temperature (SST), salinity, aragonite saturation state (Ω_Arag), nutrients, irradiance, water transparency, dust, current speed and intensity of cyclone activity. For many variables both mean and SD were considered, and at weekly, monthly and annually averaged time‐scales. All were transformed to a global 1° × 1° grid to generate coral reef probability maps for comparison with known locations. Model performance was compared in terms of receiver operating characteristic (ROC) curves and area under the curve (AUC) scores. Potential geographical bias was explored via misclassification maps of false positive and negative errors on test data. Results Boosted regression trees consistently outperformed other methods, although Maxent also performed acceptably. The dominant environmental predictors were the temperature variables (annual mean SST, and monthly and weekly minimum SST), followed by, and with their relative importance differing between regions, nutrients, light availability and Ω_Arag. No systematic bias in SDM performance was found between major coral provinces, but false negatives were more likely for cells containing ‘marginal’ non‐reef‐forming coral communities, e.g. Bermuda. Main conclusions Agreement between BRT and Maxent models gives predictive confidence for exploring the environmental limits of coral reef ecosystems at a spatial scale relevant to global climate models (c. 1° × 1°). Although SST‐related variables dominate the coral reef distribution models, contributions from nutrients, Ω_Arag and light availability were critical in developing models of reef presence in regions such as the Bahamas, South Pacific and Coral Triangle. The steep response in SST‐driven probabilities at low temperatures indicates that latitudinal expansion of coral reef habitat is very sensitive to global warming.