Localized dispersal and recruitment in great barrier reef corals: the helix experiment

To examine the problem of how far coral larvae disperse from their natal reef, coral recruitment densities were experimentally determined at distances up to 5 kilometers from a small, relatively isolated platform reef, Helix Reef, on the central Great Barrier Reef for 7 months. High concentrations of recruits, accounting for up to 40 percent of all recruitment, were found downstream of the reef in areas of high water residence time, suggesting that near-field(proximal) circulation has a profound influence on dispersal and recruitment of coral larvae. Coral recruitment declined logarithmically with distance from the reef, decreasing by an order of magnitude at radial distances of only 600 to 1200 meters. On an ecological time scale, advective dispersal of semipassive marine larvae with relatively short planktonic lives(minimally days) may be extensive, but success of recruitment is highly limited. Through evolutionary time, sufficient dispersal occurs to ensure gene flow to reef tracts hundreds or possibly thousands of kilometers apart. In the short term, however, coral reefs appear to be primarily self-seeded with respect to coral larvae.     

Connectivity and management of caribbean coral reefs

Surface current patterns were used to map dispersal routes of pelagic larvae from 18 coral reef sites in the Caribbean. The sites varied, both as sources and recipients of larvae, by an order of magnitude. It is likely that sites supplied copiously from "upstream" reef areas will be more resilient to recruitment overfishing, less susceptible to species loss, and less reliant on local management than places with little upstream reef. The mapping of connectivity patterns will enable the identification of beneficial management partnerships among nations and the design of networks of interdependent reserves.     

Episodic fluctuations in larval supply

The lack of a clear relationship between spawning output and recruitment success continues to confound attempts to understand and manage temporally variable fish populations. This relationship for a common reef fish is shown to be obscured by nonlinear processes in operation during the larval phase. Nonlinear responses of larval fish to their noisy physical environment may offer a general explanation for the erratic, often episodic, replenishment of open marine populations.     

惠东大星山人工鱼礁区渔业资源评价

为了对惠东人工鱼礁的投放进行评估以及观察对渔业资源的生物聚集效果,分别于2008年5月和2011年6月对惠东大星山人工鱼礁区进行了拖网和刺网的本底调查和跟踪调查。采用生物资源密度指数(D)、Margalef种类丰度指数(R)、Shannon-Winener多样性指数(H')、Pileou均匀度指数(J')来研究水域生物种群的多样性和资源密度。拖网调查结果表明,投礁后礁区游泳生物种类数、总资源密度、种类丰度指数、多样性指数均有明显的增加,分别为投礁前的1.321倍、2.070倍、1.012倍、1.084倍。刺网调查结果表明,投礁后礁区游泳生物种类数、总资源密度、种类丰度指数、多样性指数,分别为投礁前的2.571倍、7.976倍、2.399倍、2.667倍。投礁后礁区鱼蟹类成为主要的优势类群。这表明鱼礁投放后,对鱼类等的诱集效果显著,群落结构明显优化,礁区水域环境,明显改善。惠东大星山礁区的人工鱼礁增殖体系已基本形成。     

江门三号人工鱼礁集鱼效果初步评价

为了解江门三号人工鱼礁的投放对游泳生物的诱集效果,分别于2003年1月和2008年9月对江门三号人工鱼礁区进行了拖网和刺网的本底调查和跟踪调查.采用生物资源密度指数(D)、Margalef种类丰度指数(R)、Shannon-Winener多样性指数(H′)、pileou均匀度指数(J＇)来研究水域生物的资源密度和种群多...     

元宝山南方红豆杉克隆种群生长型研究

以广西元宝山的南方红豆杉无性系种群为研究对象,对其克隆分株的数量、形态特征(分株高度、基径、间隔物长度、分株位移)等进行调查分析,采用一个连续统指数对克隆构型进行定量描述,进而分析了克隆生长型与种群更新的关系.结果表明不同样地中南方红豆杉克隆分株的形态特征有差异,分株平均高度和基径为2.45m和6.2cm.克隆构型指数在0.6～0.87之间,变化范围较大,说明元宝山南方红豆杉无性系种群的克隆构型在不同的生境中有较大变化.采用的克隆构型指数能较好的描述南方红豆杉无性系的克隆构型特征,用指数描述的结果与形态学性状判断的结果具有一致性.元宝山的南方红豆杉种群更新包括种子更新和分株更新,自然状态下以分株更新为主.趋于"游击型"的南方红豆杉分株更新占优势,种子更新形成的幼苗很少见到;趋于"密集型"的南方红豆杉种子更新的比例增大.     

A general model for designing networks of marine reserves

There is debate concerning the most effective conservation of marine biodiversity, especially regarding the appropriate location, size, and connectivity of marine reserves. We describe a means of establishing marine reserve networks by using optimization algorithms and multiple levels of information on biodiversity, ecological processes (spawning, recruitment, and larval connectivity), and socioeconomic factors in the Gulf of California. A network covering 40% of rocky reef habitat can fulfill many conservation goals while reducing social conflict. This quantitative approach provides a powerful tool for decision-makers tasked with siting marine reserves.     

开口比变化对人工鱼礁流场效应影响的评价

针对人工鱼礁周围复杂的流场效应进行的研究已经较为成熟,然而对于不同开口比的人工鱼礁对流场效应影响的系统评价并未提出。针对一组不同开口比的人工鱼礁进行数值模拟,提出关于人工鱼礁流场效应影响的评价体系,并对不同开口比的人工鱼礁的流场效应进行全面评价。评价结果认为开口单体人工鱼礁优于不开口的实心鱼礁,但开口不应过大,在单孔鱼礁情形下,开口比为0.04时流场效应最优。     

Calcium carbonate production of the mare incognitum, the upper windward reef slope, at enewetak atoll

Corals and algal pavement produce calcium carbonate more slowly on the windward reef slope of Enewetak Atoll than on the reef flat despite the high standing crop of reef-building organisms on the slope. The capacity of reefs to remain at or near sea level is therefore not determined primarily by growth on the seaward slope.     

Caribbean reef development was independent of coral diversity over 28 million years

The relationship between natural variations in coral species diversity, reef development, and ecosystem function on coral reefs is poorly understood. Recent coral diversity varies 10-fold among geographic regions, but rates of reef growth are broadly similar, suggesting that diversity is unimportant for reef development. Differences in diversity may reflect regional differences in long-term biotic history in addition to environmental conditions. Using a combination of new and published fossil and stratigraphic data, we compared changes in coral diversity and reef development within the tropical western Atlantic over the past 28 million years. Reef development was unrelated to coral diversity, and the largest reef tracts formed after extinction had reduced diversity by 50%. High diversity is thus not essential for the growth and persistence of coral reefs.     

獐子岛深水人工鱼礁区大泷六线鱼生长特性研究

为评估獐子岛深水人工鱼礁区大泷六线鱼Hexagrammos otakii的生长特性及其资源变动情况,利用Von Bertalanffy生长方程分析了该海域大泷六线鱼体长与体质量的关系式、生长方程、各项生长参数和生长特征变化情况,运用FISATⅡ软件评估了鱼礁区大泷六线鱼的可捕资源量,分析了投放人工鱼礁对大泷六线鱼生长特性及资源量的影响,并提出了大泷六线鱼渔业资源可持续发展管理措施及资源合理利用的建议。结果表明:人工鱼礁区大泷六线鱼的平均体长和体质量随年份的增加基本呈上升趋势,优势体长组和优势体质量组随年份的增加均呈递增趋势,优势体长组为161~200 mm,优势体质量组为81~120 g;体质量生长的拐点年龄为3.75 a,种群生物量增长的临界年龄为3.73 a,总瞬时死亡率为0.483/a;根据体长股分析法,计算出鱼礁区(800 hm~2)大泷六线鱼可捕资源量为1571.6 t(约196.4 g/m~2)。研究表明,合理的捕捞限制应为3.73 a,最小不低于3 a,对体长小于281.6 mm、体质量小于273.7 g的大泷六线鱼应予以保护。     

双层十字翼型人工鱼礁流场效应的数值模拟

本文基于Ansys Fluent平台,采用湍流模型中的大涡模拟方法（large eddy simulation, LES）对双层十字翼型人工鱼礁四种子礁的流场效应进行了数值模拟,采用比混凝土体积法分析其背涡流体积、上升流体积、向上水体输运通量等流场效应数据,得到双层十字翼型鱼礁的最优礁体构造,以期为人工鱼礁的设计和选型提供科学依据。结果表明：双层十字翼型鱼礁加顶板对流场效应并无增益,上升流和背涡流相对体积变小;侧板结构对礁体的上升流和背涡流效应有明显的增益,上升流和背涡流相对体积逐渐变大,全侧板D型礁体的上升流和背涡流效应最强,上升流相对体积可达无侧板B型礁体的13.50~25.48倍,背涡流相对体积达1.40~1.61倍;向上水体输运通量约在一倍礁高处达到最大值,约在两倍礁高处降为最大值的1/2左右。迎流角度的改变,对D型礁体流场效应的影响无显著差异,表明本型礁体对自然海域的潮流流向有很好的适应性。     

沉降对多孔方型人工鱼礁流场效应影响的数值模拟

礁体沉降作为人工鱼礁投放后普遍产生的现象,对人工鱼礁周围流场会产生影响。为研究多孔方型人工鱼礁不同沉降情况下流场效应的变化,采用计算流体动力学(Computational fluid dynamics,CFD)技术,利用Fluent软件模拟在固定来流流速为0.8 m/s时,5种不同沉降程度下单体鱼礁周围的流场情况。结果显示:与无沉降时(初始状态)相比,在沉降程度为20%时,上升流最大高度降低约1.0 m,最大上升流流速增大约0.015 m/s,侧向流速增大区域(大于来流速度)扩大至1.5倍左右,同时礁体背流面透水区域增大,背涡流区域沿水流方向移动约2 m,礁体周围流场情况一定程度上变得更加复杂;在沉降程度为40%时,上升流流速最大值与初始状态相比减少约为0.010 m/s,侧向流增大区域基本一致,此时礁体背流面透水区变化较大,有形成一个逆时针涡旋的趋势;当沉降程度达到60%时,礁体周围流场效应开始明显下降,上升流最大高度相较于初始状态降低约3.2 m,上升流最大流速降低约0.600 m/s,侧向流速增大区域与壁面间距缩短约0.4 m,背涡流区域有消失的迹象;在沉降程度达到80%时,礁体流场效应基本丧失。研究表明,对于多孔方型人工鱼礁,在沉降程度40%以内,人工鱼礁仍然能够发挥着较好的流场效应;礁体在沉降程度达到60%时,礁体周围流场复杂程度相较于初始状态有明显损失,之后随着沉降深度增加,礁体流场效应逐渐消失。     

镂空型人工鱼礁流场效应的数值模拟研究

应用CFD软件对中空结构梯形台鱼礁和方型鱼礁在非定常流作用下的三维流场进行了数值模拟,揭示了两类鱼礁形成的上升流、背涡流的规模和强度,分析了单体鱼礁和组合鱼礁的流场差异。数值模拟结果表明:梯形台鱼礁上升流区最大速度约为来流速度的0.58~0.67倍、上升流区平均速度约为来流速度的0.15~0.19倍、而上升流区的最大高度为礁体高度的2.12~2.49倍,背涡流区平均速度约为来流速度的0.35~0.36倍、背涡流区的最大宽度约为礁体宽度的1.40~1.61倍、组合鱼礁背涡流区的最大长度约为礁体高度的4.06~4.17倍;方型鱼礁上升流区最大速度约为来流速度的0.56~0.61倍、上升流区平均速度约为来流速度的0.15~0.17倍、而上升流区的最大高度为礁体高度的2.22~2.63倍,背涡流区平均速度约为来流速度的0.30~0.35倍、背涡流区的最大宽度约为礁体宽度的1.75~2.00倍、组合鱼礁背涡流区的最大长度约为礁体高度的3.90~4.06倍。从流场调控效果来看,在相同模拟工况下,选择方型鱼礁比梯形台鱼礁能够更好地发挥鱼礁的环境资源修复功能。     

Acanthaster: effect on coral reef growth in panama

Analysis of data on coral abundance and growth, and the population size (26 individuals per hectare) and feeding rate of Acanthaster indicates that Pocillopora reefs on the Pacific coast of Panama are undergoing vigorous growth in the presence of this predator. Prediction of the effects of a population increase in Acanthaster to plague proportions (2.5 times that presently observed) suggests that reefs could still maintain a positive growth. However, Acanthaster at ten times the present population density would lead to rapid destruction of reefs. It is argued that coral destruction due to Acanthaster represents only one of several factors affecting coral reef progression.     

Homeward sound

Despite spending weeks at sea as larvae, potentially scattered over many kilometers, young coral reef fish find suitable settlement habitat and in some cases return to their natal reefs. We report that some dominant families of larval reef fish use the sounds made by fish and shrimp resident on reefs to help them locate and settle on reefs and that some fish groups use specific components of the reef sound to guide their behavior. These findings could offer potential for active management of reef fisheries.     

广东省澄海莱芜拟建礁区建礁可行性研究

根据2003年5月广东省澄海菜芜拟建人工鱼礁区海域和对比区海域本底调查所获资料,从水文、水质、底质、生物环境等方面分析了在拟建礁区建礁的优越性。结果表明,莱芜拟建人工鱼礁区海域水深8.5-11.0m,海面波高小于1m,拟建礁区相对于对比I墨具有明显的建礁优越性：流速较平缓,投礁后礁体所受到的波流影响较小、稳定性较强;拟建礁区的海水透明度高于对比区,更适合营光合作用的浮游生物和礁体附着生物生长;各站位pH值的平面分布和垂直分布都比较均匀;海水质量基本达到国家二类海水水质标准;表层沉积物类型主要为细砂、粘土-砂质粉砂、粉砂质砂和粘土质粉砂,属于硬质底质泥沙底,可减缓礁体投放下沉时的冲击力,投礁后礁体稳定性较强;浮游植物、浮游动物和底栖生物的栖息密度和生物多样性均高于同期调查的对比区;拟建礁区游泳生物的栖息密度明显比对比区高;鱼卵仔鱼数量较多;拟建礁海域以前是良好的渔场,附近无工业废水排放。因此,在澄海菜芜拟建礁区建礁是可行的。     

Dimethylsulfoniopropionate as a foraging cue for reef fishes

Coral reefs resemble islands of productive habitats where fishes aggregate, forage, and spawn. Although it has been suggested that some reef fishes use biogenic chemicals as aggregation cues, specific chemicals have not been identified. Dimethylsulfoniopropionate (DMSP), a secondary metabolite of many marine algal species, is released during foraging by higher-order consumers. DMSP has been studied intensively for its role in oceanic sulfur cycles and global climate regulation, but its ecological importance to marine fishes is unknown. We present evidence that planktivorous reef fishes will aggregate to experimental deployments of DMSP over coral reef habitats in the wild.     

不同结构模型礁对许氏平鲉幼鱼的诱集效果

用鱼类行为学方法,观测了许氏平鲉Sebastes schlegeli幼鱼在水槽内无模型礁和有模型礁条件下的行为反应,并统计分析了PVC材质的5种结构模型礁对许氏平鲉幼鱼的聚集率。结果表明:水槽中无模型礁的条件下,标志区(模型礁设置区)的许氏平鲉聚集率为0,许氏平鲉选择光线较弱区域栖息;放入模型礁的条件下,5种模型礁均对许氏平鲉具有明显的诱集作用,群体重心在礁体周围移动,标志区对鱼的聚集率为56.7%~90%。方差分析结果表明:5种模型礁对许氏平鲉的诱集作用无明显差异,许氏平鲉对不同模型礁均表现出明显的趋集反应。     

铅直二维定常流中人工鱼礁流场效应的数值实验

以定常来流海域为例,利用数值实验方法,定量探讨了具有自由水面的海域中人工鱼礁单体对流场的影响。考虑嵊泗鱼礁投放区的流速、水深的调查结果,来流速度Uin、水深H分别取为0.7 m/s、20 m。在鱼礁为实心方体的情况下,在渔礁迎流面产生上升流背流面产生涡流;上升流域的规模、强度随着礁高增大而增大,而上升流面积的平均产量与边际产量随礁高先增后减,在礁高水深比r=0.1时上升流效应最佳;背涡流域的规模也随着礁高增大而增大,其面积的平均产量随礁高先增后减,在r=0.1时达到极值。