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.     

海州湾人工鱼礁海域鱼类和大型无脊椎动物群落组成及结构特征

为了解人工鱼礁区鱼类和大型无脊椎动物的数量变动及群落扰动情况,于2003、2004、2005和2007年采用底拖网对人工鱼礁区及邻近对照区进行了调查。结果表明:海州湾人工鱼礁区调查共鉴定鱼类和大型无脊椎动物96种,其中鱼类和节肢类是人工鱼礁区游泳生物的主要种类,分别占55.21%和35.42%,而软体类与棘皮类则分别占7.29%和2.08%。鱼礁区的生物种类数、生物量、丰富度和多样性指数除了呈现明显的季节变化外,年平均生物种类数、生物量、丰富度和多样性均高于对照区,鱼礁增殖效果明显。此外,通过ABC曲线分析发现:除投礁后第4年的鱼礁区春季和秋季外,投礁前和投礁后第1年、第2年的鱼礁区以及对照区各季节的鱼类和大型无脊椎动物群落结构都处于一个扰动状态。     

Global trajectories of the long-term decline of coral reef ecosystems

Degradation of coral reef ecosystems began centuries ago, but there is no global summary of the magnitude of change. We compiled records, extending back thousands of years, of the status and trends of seven major guilds of carnivores, herbivores, and architectural species from 14 regions. Large animals declined before small animals and architectural species, and Atlantic reefs declined before reefs in the Red Sea and Australia, but the trajectories of decline were markedly similar worldwide. All reefs were substantially degraded long before outbreaks of coral disease and bleaching. Regardless of these new threats, reefs will not survive without immediate protection from human exploitation over large spatial scales.     

基于DIDSON的水库鱼类资源探测与时空分析

为获取上海市陈行水库鱼类时空分布特征，分别于2019年4月17日、8月15日和11月13日，采用双频识别声呐（Dual-frequency Identification Sonar，DIDSON）对陈行水库进行鱼类资源探测，利用ECHOVIEW水声数据处理软件构建鱼类目标分析模型，开展鱼类目标的提取与计数，分析并绘制鱼类资源密度的水平和垂直分布图，揭示水库鱼类数量和时空分布特征。结果表明：1）陈行水库中小型鱼类（其体长<0.6 m）居多，占比达80.9 %；2）春季至秋季库区鱼类体长逐渐增加，密度不断增大，数量和总重量也在增加；3）水平空间尺度上，库区鱼类个体主要集聚在水库南部，夏季分布相对集中，秋季相对分散；4）垂直空间尺度上，库区鱼类主要分布在水深2～6 m区间，占比达84.85 %，春季鱼类分布平均水深为3.89 m，夏季为4.34 m，秋季为5.12 m，库区鱼类垂直分布随季节有向底层移动趋势。本文所研究的水声探测方法和鱼类目标分析模型，为类似的鱼类资源调查分析工作提供了有益参考，探测结果为水库采取合理的鱼类资源管理提供了依据。     

人工鱼礁的环境功能与集鱼效果

人工鱼礁是用于改善海域生态环境，建设渔场和增养殖场的人工设施。人工鱼礁投放到海中后，使周围海域的流、光、音、底质等非生物环境发生变化，这种变化又引起生物环境的变化，使水生生物量增大，从而形成良好的渔场或增养殖场，焦鱼效果也非常明显。本文作者综述了人工鱼礁的环境功能和焦鱼效果，并分析了今后人工鱼礁研究的发展趋势，特别是人工鱼礁在海洋生态环境改造方面的应用前景。     

Local replenishment of coral reef fish populations in a marine reserve

The scale of larval dispersal of marine organisms is important for the design of networks of marine protected areas. We examined the fate of coral reef fish larvae produced at a small island reserve, using a mass-marking method based on maternal transmission of stable isotopes to offspring. Approximately 60% of settled juveniles were spawned at the island, for species with both short (<2 weeks) and long (>1 month) pelagic larval durations. If natal homing of larvae is a common life-history strategy, the appropriate spatial scales for the management and conservation of coral reefs are likely to be much smaller than previously assumed.     

Detection, pursuit, and overgrowth of tropical gorgonians by milleporid hydrocorals: perseus and medusa revisited

Encounters leading to competitive interactions between colonies on coral reefs are to some extent accidents of patterns of recruitment and growth. In contrast, colonies of Millepora spp. actively detect nearby arborescent gorgonians and subsequently redirect growth in order to contact and overgrow them. Detection is dependent on water flow over the two colonies.     

Climate change,human impacts,and the resilience of coral reefs

The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.     

Bushmeat hunting, wildlife declines, and fish supply in West Africa

The multibillion-dollar trade in bushmeat is among the most immediate threats to the persistence of tropical vertebrates, but our understanding of its underlying drivers and effects on human welfare is limited by a lack of empirical data. We used 30 years of data from Ghana to link mammal declines to the bushmeat trade and to spatial and temporal changes in the availability of fish. We show that years of poor fish supply coincided with increased hunting in nature reserves and sharp declines in biomass of 41 wildlife species. Local market data provide evidence of a direct link between fish supply and subsequent bushmeat demand in villages and show bushmeat's role as a dietary staple in the region. Our results emphasize the urgent need to develop cheap protein alternatives to bushmeat and to improve fisheries management by foreign and domestic fleets to avert extinctions of tropical wildlife.     

Projecting coral reef futures under global warming and ocean acidification

Many physiological responses in present-day coral reefs to climate change are interpreted as consistent with the imminent disappearance of modern reefs globally because of annual mass bleaching events, carbonate dissolution, and insufficient time for substantial evolutionary responses. Emerging evidence for variability in the coral calcification response to acidification, geographical variation in bleaching susceptibility and recovery, responses to past climate change, and potential rates of adaptation to rapid warming supports an alternative scenario in which reef degradation occurs with greater temporal and spatial heterogeneity than current projections suggest. Reducing uncertainty in projecting coral reef futures requires improved understanding of past responses to rapid climate change; physiological responses to interacting factors, such as temperature, acidification, and nutrients; and the costs and constraints imposed by acclimation and adaptation.     

北部湾中北部海域鱼类群落的季节变化特征

【目的】明确北部湾中北部海域鱼类群落种类组成、密度分布及多样性指标等参数的时空演变特征,为后续开展北部湾海域鱼类群落结构长时间序列变化和时空分布规律研究积累基础资料,同时为该海域渔业资源的可持续开发利用及科学管理提供参考依据。【方法】分别于2016年2月（冬季）、5月（春季）、8月（夏季）和11月（秋季）,在北部湾中北部沿岸海域采用底拖网方式进行4航次渔业资源调查,采用面积法计算各季节的鱼类资源生物量和丰度,依据Pinkas相对重要性指数（IRI）确定鱼类群落结构中的优势种,并通过Shannon-Weiner多样性指数（H' ）、Pielou均匀度指数（J' ）和Margalef丰富度指数（D）分析各调查站位的鱼类群落结构多样性。【结果】北部湾中北部近岸海域4个季节共渔获鱼类152种,隶属于15目55科96属,均为暖水性或暖温性种类。北部湾中北部海域的鱼类资源生物量和丰度分布不均匀,但二者的变化趋势基本一致,表现为春夏季的生物量和丰度均明显高于秋冬季。北部湾中北部海域各季节鱼类的H'在1.952~2.590,其排序为夏季>春季>秋季>冬季;J'在0.481~0.699,各季节排序为春季>夏季>秋季>冬季;D以夏季最高（3.114）、冬季最低（2.303）,各季节排序为夏季>秋季>春季>冬季。北部湾中北部海域各季节的鱼类资源优势种（IRI≥1000.00）存在明显差异,其中春季有3种、夏季有5种、秋季有4种、冬季有2种;二长棘鲷（Parargyrops edita）为4个季节鱼类资源的共有优势种,褐菖鲉（Sebastiscus marmoratus）是春季和冬季鱼类资源的共有优势种,鹿斑鲾（Secutor ruconius）是夏季和秋季鱼类资源的共有优势种。【结论】北部湾中北部海域鱼类资源时空变化明显,群落多样性指数较历史水平偏低,鱼类资源处于过渡开发状态,且鱼类资源优势种更替的总体趋势表现为k选择种类被r选择种类所替代。鱼类资源季节变动与鱼类洄游习性、海水温度变化及伏季休渔制度等因素有关。     

Spatial and temporal stability of soil phosphate concentration and pasture dry matter yield

Several methods are described that could be used by a farm manager to define the spatial and temporal stability within a field from a series of yield maps. A quantitative analysis of soil phosphate concentration and pasture dry matter yield data over 4 years (2004–2007) were investigated to identify the spatial and temporal stability in a 6 ha pasture field. The data were combined into two maps that characterize the spatial and temporal variation recorded over the 4 years. The two maps were then combined to create a single map with five management classes, each with different characteristics that can have an impact on the way the field is managed. These categories are: high yielding and stable, high yielding and moderately stable, low yielding and stable, low yielding and moderately stable and unstable. The unstable class represents 83 and 93% of the total area with regard to soil phosphate concentration and pasture dry matter yield, respectively. Results from this study show that the significant temporal stability found cancels out over time, leaving a relatively homogenous map of spatial variation. The implication of the findings is that each pasture field should be managed according to the current year’s conditions. These results also justify a further study that evaluates the soil phosphorous dynamics under Mediterranean conditions.     

东北地区近50年地表干湿状况的变化趋势

利用1955～2004年我国东北地区46个测站降水和气温资料,通过5日滑动平均法,确定≥10℃的界限日期,并计算界限时期内的积温值,用积温值与同一时期的降水量的比值表示干燥度,分析了东北地区每10年干湿状况的时空分布规律及变化趋势。结果表明,东北地区的干湿状况具有明显的时空变化特征,总体而言,东北地区近50年干湿状况呈变干的趋势。     

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.     

Interocean differences in size and nutrition of coral reef sponge populations

Sponges consume an order of magnitude more organic matter on Caribbean coral reefs than on the Great Barrier Reef. This rate of consumption is attributed to Caribbean sponge biomass being five to six times greater than that on the Great Barrier Reef, on average, and to the absence in the Caribbean of phototrophic sponges, which are a feature of clean water regions of the Great Barrier Reef. The long temporal and spatial separation of the Atlantic and Pacific oceans has resulted in the evolution of dissimilar sponge faunas, with Caribbean sponges being heterotrophic, whereas many Great Barrier Reef sponges rely on nutritional input from photosynthetic symbionts.     

长江如皋江段仔稚鱼资源现状调查分析

【目的】调查长江如皋江段仔稚鱼资源现状,探索仔稚鱼物种组成、生态类型、群落特征及仔稚鱼丰度时空特征,为长江近河口段仔稚鱼资源监测提供基础数据。【方法】采用鱼类早期资源调查方法对仔稚鱼进行采样调查,将仔稚鱼样品在Olympus SZX 16体视解剖镜下进行种类鉴定,对部分形态特征残缺难以辨认及不确定种类的仔稚鱼进行细胞色...     

Night-Shocker: Predatory Behavior of the Pacific Electric Ray (Torpedo californica)

Diving observations off Santa Barbara, California, indicate that Pacific electric rays (Torpedo californica) enter inshore reefs at night and actively prey on fish with the aid of powerful electric discharges.     

Pleistocene sea levels from raised coral reefs of haiti

The elevations and ages of a sequence of three uplifted Pleistocene coral reefs on the Northwest Peninsula of Haiti have been determined. With the assignment of a sea level of +6 meters (relative to the present day) at 130,000 years before present and constant uplift of the reefs, the data indicate that sea level stood -10 and -13 meters at 108,000 and 81,000 years before present, respectively. These results are in substantial agreement with those reported for Barbados and New Guinea and support the hypothesis of constant uplift for each area. Sea level data from raised reefs indicate that the interglacial marine oxygen isotope oscillations during oxygen isotope stage 5 are a result of 30 percent ice volume effects and 70 percent temperature effects.     

Toxicity in sponges and holothurians: a geographic pattern

Toxicity in sponges and holothurians is inversely related to latitude and may reach 100 percent for holothurians in high-diversity coral reefs. Evidence from approximately 700 experiments and from underwater observations suggests that predation by fish has resulted in natural selection for noxious and toxic chemical compounds in species within these taxa.     

近海中上层柔性浮鱼礁设计与应用

当前我国海洋牧场建设、栖息地改造主要通过底层鱼礁进行,从产生营养物质上升流、饵料场和产卵场及生物链的角度未充分利用整个水体空间,导致效能不能发挥到最佳。为解决这一问题,针对我国东海近海海域海况和生物特性研发了能与底层人工鱼礁协同工作的中上层浮鱼礁。从改善流场、自身体积保持等角度设计了四层网格式柔性浮式鱼礁,进行了浮力、重力及抗浪流能力的校核计算,确定了锚系技术方案及水下效果监控方法。在象山港海洋牧场进行了布放,实际效果测试表明所设计的浮鱼礁可以有效改善区域流场,在最高潮和最低潮时均可保持竖直方向的拉伸状态,最大潮流速度时倾斜角度不超过20度,现场多批次调查及水下视频监控效果显示所研发的鱼礁能够与底层鱼礁协同工作,投放2个月后有鱼类稳定地出现在浮鱼礁周围,取得了良好的效果。