Characterising reef fish populations and habitats within and outside the US Virgin Islands Coral Reef National Monument: a lesson in marine protected area design

Abstract  Marine protected areas are an important tool for management of marine ecosystems. Despite their utility, ecological design criteria are often not considered or feasible to implement when establishing protected areas. In 2001, the Virgin Islands Coral Reef National Monument (VICRNM) in St John, US Virgin Islands was established by Executive Order. The VICRNM prohibits almost all extractive uses. Surveys of habitat and fishes inside and outside of the VICRNM were conducted in 2002–2004. Areas outside the VICRNM had significantly more hard corals, greater habitat complexity, and greater richness, abundance and biomass of reef fishes than areas within the VICRNM. The administrative process used to delineate the boundaries of the VICRNM did not include a robust ecological characterisation of the area. Because of reduced habitat complexity within the VICRNM, the enhancement of the marine ecosystem may not be fully realised or increases in economically important reef fishes may take longer to detect.     

The effect of a closed area and beach seine exclusion on coral reef fish catches

Fish landing data from the Mombasa Marine National Park (MNP) and a marine reserve exploited by various gears were studied over a 5‐yr period to determine the influence of the closed area and different gears in fisheries. The number fishing and boats per landing site was constant, but total and catch per unit effort progressively declined in all sites on an annual basis irrespective of the existence of a marine reserve, exclusion of the beach seines or use of gear. Differences between landing sites were most pronounced when analysed on a catch per area as opposed to the more standard catch per fisherman, suggesting compensation in human effort when catches decline. A marine reserve next to a closed area that excluded beach seines had the highest catch per area (5.5 kg ha^?1 month^?1) despite having the highest density of fishermen (0.07 ± 0.02 fishermen ha^?1 month^?1). The annual rate of decline in the catch was lower than the other sites at around 250 g day^?1 compared with 310–400 g day^?1 in the other sites. One landing site, which excluded beach seine landings for more than 20 yrs, had a high catch per area (～5.3 kg ha^?1 month^?1), but after experiencing a doubling in the effort of other gears (line, speargun and trap), the catch per fisherman and area were reduced. Environmental or habitat degradation and excessive effort remain the most likely explanation for the overall declines in catch from 1995 to 1999. Closed areas and beach seine exclusion have the potential to increase catch rates, but the first often reduces the total fishing area and possibly leads to a loss of total catch, at least on a time scale of less than 10 yrs. The exclusion of beach seines can lead to an increase in other gear types that can also cause reductions in catch.     

Structures,dynamics and stability of reef fish assemblages in non‐reefal coral communities in Hong Kong,China

• 1. A detailed study on the spatial and temporal patterns of reef fish assemblages associated with non‐reefal coral communities at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, China, was carried out using an underwater visual census method from January 1998 to December 1999.
• 2. The study identified a total of 106 species (76 genera in 39 families) of fish in the study sites, in which 88 species were recorded in AMW and 78 species in AYW. Seasonal patterns in the abundance and species richness of all reef fishes and most of the frequently encountered families/trophic groups in both study sites were observed. Seasonal fluctuation of macroalgae, the influence of recruitment of larvae, and the possible seasonal variation in the behaviour of fish may all contribute to these observed seasonal patterns.
• 3. Multidimensional scaling (MDS) ordinations demonstrated that there were spatial variations in the fish community structures within and between sites. Such spatial patterns were possibly related to the spatial variation of the coral community structures in the study sites. The ordinations also showed that the fish community structures in the study sites were not seasonally stable. Such temporal instability of the fish community structures may be partly due to habitat isolation among the fish communities around the island.
• 4. These results imply that preservation and enhancement of habitat connectivity of the coral communities should be one of the main conservation strategies for the reef fish communities of Tung Ping Chau, and those of Hong Kong in general. This strategy may be equally applicable to other non‐reefal coral communities elsewhere around the world.

Copyright © 2008 John Wiley & Sons, Ltd.     

Human‐induced gradients of reef fish declines in the Hawaiian Archipelago viewed through the lens of traditional management boundaries

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Lessons from the past: the collapse of Jamaican coral reefs

Since Pre-Columbian times, humans have exploited Jamaican marine ecosystems with significant consequences for flora and fauna. This study focuses on the history of reef fish exploitation in Jamaica, from first human occupation to the present day, to determine how past fishing activities contributed to subsequent declines in the coral reef ecosystem. The pattern of declining reef fish populations was nonlinear. Reef fish first declined in prehistoric times but then potentially recovered, following genocide of the native human population. Reduced fishing pressure lasted until the mid-19th century. At that time, depletion of reef fish populations again occurred with a precipitous decline from the 1850s to the 1940s. The final shift from relatively abundant to overfished marine fauna corresponded to subtle changes in fish trap design as well as development of recreational fishing. Government subsidies throughout the second half of the 20th century exacerbated the declines. This analysis shows that local artisanal fisheries with relatively low levels of effort and seemingly subtle shifts in technology can significantly impact the coral reef ecosystem and that declines occurred decades to centuries before modern ecological studies began. This research shows how historical analysis can be a powerful tool to minimize shifted baselines and establish realistic targets for recovery and sustainable management of marine ecosystems.     

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。     

南沙群岛重要珊瑚礁水域鱼类资源数量分布

1998年3—5月和1999年5—6月．采用手钓、延绳钓和流刺网3种作业方式在南沙群岛的渚碧、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。结果表明,7座珊瑚礁水域不同作业方式的鱼类资源相对丰盛度差别较大,其中刺网以永暑礁最高,手钓以华阳礁最高,延绳钓以南薰礁最高;同时．刺网和手钓不同水深区域鱼类资源的相对丰盛度也不相同．其中刺网以11～30m区域最高．手钓以10m以浅和51～80m区域较高;分析认为,造成礁区之间鱼类相对丰盛度差异的主要原因不是初级生产力．而是生态环境因素,主要是礁盘形态和大型海藻的数量。另外．各礁区水域的优势类群有明显不同．这主要与洞穴的大小和数量、大型海藻及珊瑚的种类和数量等生物和非生物环境有关。     

A spatio‐temporal long‐term assessment on the ecological response of reef communities in a Caribbean marine protected area

1. Coral reef biodiversity is rapidly decreasing as a result of the loss of coral cover, which modifies the structure and functioning of the ecosystem. Understanding how coral reef communities respond in space and over the long term is essential in order to implement management strategies and reduce the effects of biodiversity loss on coral reefs.
2. Fish, coral, and algae communities were used as indicators to evaluate changes in coral reef systems. The variation of these communities was studied in a marine protected area composed of three management zones in Cozumel Coral Reef National Park in Quintana Roo, Mexico, over a period of 11 years (2004–2014). The following parameters were monitored annually: (i) total fish density; (ii) fish trophic group densities; (iii) species richness and three fish diversity indices; (iv) relative scleractinian coral cover; and (v) relative macroalgae cover.
3. In the years in which coastal development, such as the construction of a marina, took place, an increase in the abundance of territorial herbivorous and planktivorous fish was observed. As the coral recovered, macrocarnivores and sessile benthic invertivores were re‐established, whereas scraper herbivores showed no changes in the period of study in any of the three management zones.
4. Coral cover recovery showed rapid phase‐shift reversal (phase‐shift, macroalgae dominance over coral) in the three zones. Even though the fish density and coral cover recovered, the diversity indices of each fish trophic group exhibited a reduction in the three management zones over time.

     

西沙群岛七连屿礁栖鱼类物种和分类多样性

为探讨以西沙群岛七连屿（16°55''N~17°00''N,112°12''E~112°21''E）为代表的典型小尺度范围内珊瑚礁生态系统的物种组成及分类多样性,本文以20世纪70年代、2018—2019年南海七连屿鱼类调查资料为基础,总结七连屿礁栖鱼类物种组成,并利用分类学多样性指数和（科级）多样性测度指数对七连屿珊瑚礁鱼类物种组成及分类多样性进行研究。结果显示,七连屿海域礁栖鱼类隶属于8目33科70属175种,其中鲈形目（Perciformes）鱼类占绝对优势,占比81%;平均分类差异指数（Δ⁺）约为54.19,分类差异变异指数（低于东海陆架、大亚湾和渚碧礁;其G-指数）平均值为3.09,标准化的F-指数、指数综合来看,七连屿礁栖性鱼类物种多样性较高,且其科、属的分布在历史上较为合理,但2018—2019年科属多样性显著降低,建议对其及时予以保护。     

Larger biomass of targeted reef fish in no‐take marine reserves on the Great Barrier Reef,Australia

• 1. An expansion of no‐take marine reserve zones of Australia's 348 000 km² Great Barrier Reef (GBR) Marine Park from 4.6% to 33.4% of the park area is proposed in 2004. However, limited evidence currently exists that no‐take marine reserves on the GBR have increased abundance of reef fish targeted by fisheries. This study provides such evidence for inshore reefs of the GBR.
• 2. Underwater visual surveys were used to estimate the effect of no‐take reserves on abundance of species targeted by hook‐and‐line fisheries around the Palm, Whitsunday and Keppel Islands, spanning 600 km of the length of the GBR. The reserves had been zoned ‘no fishing’ for 14 yr.
• 3. Densities of Plectropomus spp. and Lutjanus carponotatus, both targeted by fisheries, were much higher in protected zones than fished zones in two of the three island groups. Plectropomus spp. were 3.6 and 2.3 times more abundant in protected than fished zones of the Palm and Whitsunday island groups. L. carponotatus were 2.3 and 2.2 times more abundant in protected zones than fished zones of the Whitsunday and Keppel island groups.
• 4. The biomasses of Plectropomus spp. and L. carponotatus were significantly greater (3.9 and 2.6 times respectively) in the protected zones than fished zones at all three island groups.
• 5. Legal minimum sizes of Plectropomus spp. and L. carponotatus are ?38 cm and 25 cm TL respectively. There were significantly higher densities and biomasses of Plectropomus spp. >35 cm TL (density: 3.8 times; biomass: 5.1 times) and L. carponotatus >25 cm TL (density: 4.2 times; biomass: 5.3 times) in protected zones than fished zones at all three island groups.
• 6. No significant difference in abundance between protected and fished zones was found for two species not captured by fisheries (Siganus doliatus and Chaetodon aureofasciatus), and there were no significant differences in benthic characteristics between protected and fished zones.
• 7. Results suggest that no‐take marine reserves have increased stock biomass of targeted fish species on inshore GBR reefs.

Copyright © 2004 John Wiley & Sons, Ltd.     

The influence of bottom type and shelf position on biodiversity of tropical fish inside a recently enlarged marine reserve

• 1. A necessary component of implementing a successful marine reserve is the quantification of the biological resources that fall under its protection. Without such an initial assessment, the future effects of the reserve on the local habitat and biotic community cannot be quantified and will remain the subject of debate.
• 2. This study provides such a baseline assessment of fish diversity and habitat types within a recently enlarged marine reserve. Buck Island Reef National Monument, US Virgin Islands, was recently enlarged from approximately 4 km² to over 76 km². Areas of sand, seagrass, and hard‐bottom under protection were increased from 0.29 km², 0.47 km², and 1.96 km² to 2.70 km², 2.89 km², and 18.30 km² respectively when the Monument was expanded. A 53 km² area of pelagic/deep‐water habitat with unknown bottom type is now also protected by the Monument.
• 3. Visual counts of fish within 25×4 m² transects conducted during the day were used to assess fish community structure and habitat utilization patterns. Species richness, diversity, assemblage structure, and fish density were evaluated and compared among sand, seagrass, and hard‐bottom habitats. Hard‐bottom sites had over twice the mean species richness and diversity as sand and seagrass sites, and several times greater mean fish density.
• 4. Quantification of the fish community in pelagic and deep‐water habitats within the reserve is recommended to provide a more comprehensive assessment of the offshore areas of the reserve. Fish numbers, size, and diversity outside the reserve boundaries must also be evaluated to allow quantification of the effects of the marine reserve on the adjacent fish communities.

Copyright © 2004 John Wiley & Sons, Ltd.     

Effects of fisheries management on fish communities in the floodplain lakes of a Brazilian Amazonian Reserve

Abstract –  We compared fish abundance, diversity and species composition between lakes open (fished) and closed (no-take) to fishing activities in Mamirauá Sustainable Development Reserve in the Central Brazilian Amazon, in order to investigate potential influences of the common-based management. We sampled 1483 fishes from 70 species through gillnet fishing during the low-water season, in seven fished and seven no-take lakes. Contrary to expected, the mean values for abundance, size, diversity and species-richness of fish did not differ between fished and no-take lakes. There was no difference between fished and no-take lakes considering only the abundance of the 14 fish species more intensely targeted by fishermen. However, the abundance of an important commercial fish, the tambaqui ( Colossoma macropomum ) was higher in no-take lakes. Such data from a rapid assessment may be useful to monitor this and other fishery co-management schemes.     

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%。     

西沙群岛珊瑚礁海域鱼类分类学多样性

为评价南中国海西沙群岛珊瑚礁海域鱼类分类学多样性和更好地保护其鱼类,根据西沙群岛珊瑚礁海域鱼类物种组成的历史资料对西沙群岛及其16座岛礁的珊瑚礁水域鱼类物种数目、平均分类差异指数和16座岛礁的G-F多样性指数作了分析。结果显示,西沙共记录鱼类661种,隶属于25目、93科、305属。其中,永兴岛(351种),华光礁(173种),东岛(160种)记录鱼类物种数目较多。西沙鱼类平均分类差异指数(Δ⁺)约为60.2,各岛礁的Δ⁺与物种数目无关。中建岛、晋卿岛、玉琢礁等岛礁鱼类平均Δ⁺显著低于西沙鱼类Δ⁺。西沙鱼类Δ⁺小于陆架和河口区鱼类Δ⁺,说明珊瑚礁海域鱼类亲缘关系比陆架和河口区域的都要接近,此外大尺度上,一般纬度越低,中国海洋鱼类Δ⁺越小。但G-F多样性测度各指数由物种数目的大小决定,一般物种数目较大的岛礁G-F多样性各指数也相对较高,而R_G-F指数更适合该海域鱼类多样性的测度。以石岛为例初步探讨了G-F指数为负的原因,一是物种数目较少,二是多样性测度的关键函数Y=-XLnX并不是单调函数所致;物种数目较大的岛礁如永兴岛、华光礁、东岛等应该成为西沙珊瑚礁海域鱼类保护的重点区域。     

发展海洋牧场构建“蓝色粮仓”

为了探明人工鱼礁对局地潮汐动力等因素的影响规律和机制,根据2016年7月东山海人工鱼礁区内外2个站位的25 h连续观测流速和水位数据,结合数值模拟方法,分析了广东惠州东山海人工鱼礁区建成后对礁区及周边海域潮汐动力等造成的影响。基于数值模拟,对建礁前后模拟结果对比分析获得了潮汐潮流等因子的变化情况。结果显示,模型模拟结果与实测值吻合良好;人工鱼礁区建成后对研究区域的潮汐调和常数和潮汐特性几乎没有影响;人工鱼礁区的部分分潮潮流椭圆会改变方向和转向,礁区外则几乎没有影响;建礁后礁区内部余流方向改变不大,礁区整体余流呈减小趋势;礁区附近水平流场改变明显,但对礁区外部影响范围有限,礁区迎流面有明显上升流,大潮涨急时刻底层上升流最大可达1.2 cm·s^–1,礁区后部则出现下降流。     

马鞍列岛人工鱼礁区鱼卵与仔稚鱼的群落结构

为了解人工鱼礁投放对鱼卵和仔稚鱼分布的影响,于2018年1月(冬季)、4月(春季)、7月(夏季)和10月(秋季)利用大型浮游生物网在马鞍列岛海洋牧场开展了4个航次的水平拖网调查。根据鱼卵、仔稚鱼的种类组成、数量分布等群落结构特征,对投礁区和未投礁区鱼卵、仔稚鱼的资源分布进行研究。结果显示,2018年在马鞍列岛海洋牧场共采集鱼卵5 642粒、仔稚鱼1 013尾,隶属于10目21科49种。鱼卵优势种为龙头鱼、短吻红舌鳎和小黄鱼;仔稚鱼的优势种为褐菖鲉、花鲈和小公鱼属未定种。投礁区和未投礁区鱼卵仔稚鱼的优势种种类组成基本一致,但是群落结构差异显著,投礁区各个季节的多样性指数、丰富度指数及均匀度指数均高于未投礁区,与未投礁区差异显著,且春季投礁区的生物多样性最高。聚类分析显示,春季鱼卵、仔稚鱼群落结构最为稳定,冬季群落结构最简单,夏、秋两季相似度较高,群落结构更复杂。研究表明,马鞍列岛海洋牧场人工鱼礁的投放对鱼卵、仔稚鱼具有一定的聚集和庇护作用,温度(T)、盐度(S)、水体浑浊度(Turb.)等海洋物理环境因子对鱼卵、仔稚鱼分布影响显著。     

人工鱼礁生态诱集技术的机理及研究进展

人工鱼礁是用于营造海洋牧场、调控和优化海洋生态环境、增殖渔业资源的人工设施。人工鱼礁所形成的环境可以作为鱼类良好的栖息、庇护和产卵场所,有利于鱼类的生存和繁殖,因此对鱼类具有良好的诱集效应。本文从多个角度论述了人工鱼礁生态诱集技术的机理以及鱼类行为和生态诱集技术的研究进展,探讨了目前人工鱼礁生态诱集技术研究所面临的问题和主要发展方向,旨在为我国沿海人工鱼礁建设提供一定的理论基础。     

Profile of the Marine Aquarium Fish Trade in Hong Kong

A market survey and review of government statistics were carried out to establish imports and exports of marine ornamental fishes into and out of Hong Kong, and to examine the local trade in terms of volume, value and species composition. Official government import figures for marine aquarium fishes were available from 1984 to 1991 and from 1997 and 1998. When compared with net imports, export and re-export volumes over the 15-year period were small, indicating that most imports entered the local market, or were exported unrecorded. The market survey of marine aquarium shops in Hong Kong was carried out between August 1996 and January 1997. From this survey, an annual estimate of 957,563 coral reef fish was calculated for the local trade, valued at HK$57,453,780, with a mean retail price of HK$60 per fish. These figures account for an estimated 2–3% of the global value and volume of marine aquarium fish trade, according to 1992 figures and, compared with government figures, indicate that official declarations of imports are underreported by at least 2–3 fold. A total of 342 marine aquarium fish species, from 49 families, were recorded with about 60% belonging to the families Labridae, Chaetodontidae, Pomacanthidae and Pomacentridae. It was estimated that a large proportion of the trade was in juvenile fishes and almost all fish were less than 10cm in standard length. It was common to see fishes in poor condition, species hard to maintain in captivity, or those listed for conservation concern, on sale. There are no regulations for local traders of live marine fishes other than those relating to either protected species or animal welfare. Licensing of traders in marine fishes could be introduced under existing Hong Kong legislation if fishes were to be re-classified as animals. This is strongly recommended as a step towards regulating and managing the trade in Hong Kong.