胶州湾菲律宾蛤仔生态容量评估及其碳汇功能

胶州湾是我国重要的菲律宾蛤仔(Ruditapes philippinarum)养殖基地,为探究湾内菲律宾蛤仔的生态容量及其碳汇功能,本研究采用Ecopath模型法评估了胶州湾菲律宾蛤仔的生态容量,并利用Ecosim模块动态分析了菲律宾蛤仔生物量扩大对胶州湾生态系统结构与功能特征的潜在影响,同时估算了胶州湾菲律宾蛤仔个体及种群水平的碳收支情况。结果显示,胶州湾菲律宾蛤仔的生态容量为239.9 t/km2,虽然整体水平尚未达到生态容量,但局部养殖区域已远超出了菲律宾蛤仔的生态容量;当胶州湾菲律宾蛤仔生物量从当前增加至生态容量时,生态系统总流量、容量、优势度和循环指数分别提高了16.0%、3.9%、47.1%和103.0%,而熵值降低了10.4%,表明此时生态系统具有更高的成熟度与稳定性,但菲律宾蛤仔生物量扩大至生态容量10倍时会对生态系统产生不利影响甚至崩溃;菲律宾蛤仔个体在1个养殖周期内约摄取3 310.1 mg C,其中约46.2%的碳沉降至海底,约13.2%的碳通过收获移出,如按菲律宾蛤仔生物量达到生态容量时计算,胶州湾每年将有1.5万t碳以生物沉积形式沉降至海底,有0.6万t碳以收获形式移出。研究结果为指导菲律宾蛤仔增养殖产业的健康可持续发展、阐明菲律宾蛤仔的碳汇功能提供了理论依据与数据支撑     

Habitat variability in young-of-the-year winter flounder, Pseudopleuronectes americanus, in Maine estuaries

The Magnuson-Stevens Fishery Conservation and Management Act defines essential fish habitat (EFH) as “the waters and substrate necessary to fish for spawning, breeding, feeding, and growth to maturity” and the protection of nursery areas has become a key element in US Federal fisheries management. Distribution and abundance by habitat for age-0, young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, were compared for 28 Maine estuaries to help define essential fish habitat for this life history stage. The Maine coast was divided into three broad geographic zones based upon geological features and sampled over 5 consecutive years; during April–November of 2000 in the Mid-coast, in 2001 and 2002 along the Southwest coast and in 2003 and 2004 along the Eastern Maine coast. One beam trawl (2.0 m width, 3 mm mesh) sample was collected in one to four habitats in estuaries: eelgrass (Zostera marina), kelp (Laminaria longicruris), drift algae (Phyllophora sp.) and unvegetated sand/mud. Fish were sampled every 2 weeks, April–November 2000–2004. Abundance of YOY winter flounder was greatest in Mid-coast estuaries between Casco and Penobscot Bays and was significantly lower in Southwest and Eastern estuaries. Abundance was similar across all four habitats in Mid-coast estuaries in 2000. In the other years, YOY were found in higher abundance in eelgrass relative to other habitats. A logistic regression model based on nearshore habitat characteristics was developed to predict the distribution of this species along the three broad geological zones of the Maine coast with the physical and biological variables most important in discriminating between habitats with and without individual fish identified. This logistic regression model correctly classified winter flounder 72.4% of the time based on the year, zone, the physical habitat variables (temperature, salinity, depth) and the presence–absence of submerged aquatic vegetation (eelgrass, kelp or algae). These results indicate that the type of habitat most important to YOY winter flounder varies among estuaries and EFH for this species and life stage must be defined with care.     

Depth matters for bivalve culture in integrated multitrophic aquaculture (IMTA) and other polyculture strategies under non-eutrophic conditions

Bivalve cultivation, in single cultivation or in polyculture (including integrated multitrophic aquaculture; IMTA), is generally limited to eutrophic waters. We carried out a modeling study to test if, under meso- and oligotrophic conditions, depth could be a key factor for bivalve productivity associated to IMTA and other polyculture strategies. We applied the model Farm Aquaculture Resource Management (FARM) at three strata of the water column in two coastal fish farm areas in the Mediterranean Sea, using water column variables sampled seasonally to estimate the potential mussel production. According to FARM, mussel production was high in both areas and, in some cases, almost doubled when mussels were cultured below 25-m depth compared to shallower levels. Phytoplankton abundance is expected to notably influence mussel production compared to particulate organic matter. Thus, in meso- and oligotrophic stratified waters, where chlorophyll maximum is relatively deep, depth can be a key factor for the productivity of mussel cultivation. The obtained results could help to maximize the production of suspension-feeding bivalve cultivation and, therefore, the expansion and development of sustainable aquaculture in non-eutrophic marine waters.     

Goods and services of extensive aquaculture: shellfish culture and nutrient trading

Bivalve shellfish play an important role in top-down control of primary symptoms of eutrophication. This short-circuits the process of organic decomposition and promotes an enhancement of underwater light climate, improved oxygenation of bottom water, and restoration of submerged aquatic vegetation. This review analyses this ecosystem service as a potential actor in watershed-level nutrient credit trading programmes and explores the possibilities of implementation of such programmes in Europe. We examine the different components of the issue, including the eutrophication status of European coastal waters, legal and management instruments, and the use of mathematical models at both the ecosystem and farm scales to evaluate the potential removal of nitrogen by cultivated shellfish such as oysters, mussels, and clams. The annual European bivalve shellfish production of over 700,000 metric tons is estimated to generate a nitrogen removal of 46,800 t year^?1, equivalent to 14 × 10⁶ population equivalent, and a minimum value of 507 × 10⁶ €. We discuss future directions for this topic in Europe, drawing from ongoing research in the USA and elsewhere, in the light of the twin challenges of European aquaculture expansion and implementation of EU directives.     

Long‐term stability of eelgrass fish assemblages in two highly developed coastal estuaries

Changes in fish assemblages were tracked in representative eelgrass (Zostera marina L.) beds within two estuaries on the urbanised coast of southern California, USA, San Diego Bay and Mission Bay, from 1987 to 2010. Assemblages were sampled twice yearly (spring and summer) at day and night using beach seines. Assemblage stability was examined over time along with changes in assemblage structure across time of day and season, including the influence of temporally variable abiotic variables. Only the occasionally occurring fish, those present in <70% of samples, in Mission Bay appeared to be shifting to a new assemblage. Although season and sampling time significantly affected assemblages, correlations with abiotic factors were low. Given the long history of urban development of these estuaries, community shifts may have occurred prior to the onset of sampling, giving the appearance of stability. Alternatively, eelgrass habitat may be providing a refuge from long‐term disturbances.     

Seasonal effects of clams (Panopea generosa) on eelgrass (Zostera marina) density but not recovery dynamics at an intertidal site

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Don't go breaking apart: Anthropogenic disturbances predict meadow fragmentation of an endangered seagrass

1. Although it is well established that human activities are linked to the loss of seagrasses worldwide, the influence of anthropogenic disturbances on the habitat fragmentation of seagrass meadows is less understood. This information is essential to identify how humans are modifying seascapes and what disturbances pose the greatest risk to seagrasses, which is pertinent given the rapid urbanization occurring in coastal areas.
2. This study examined how the habitat fragmentation of an endangered seagrass Posidonia australis varied in relation to several anthropogenic disturbances (i.e. human population, marine infrastructure, terrestrial run-off and catchment land-usage) within 10 estuaries across 620 km of coastline in New South Wales, Australia.
3. When comparing between estuaries, the fragmentation of P. australis meadows was significantly greater in estuaries adjacent to highly populated metropolitan centres – generally in the Greater Sydney region. At sites within estuaries, the density of boat moorings was the most important predictor of habitat fragmentation, but there was also evidence of higher fragmentation with increased numbers of jetties and oyster aquaculture leases.
4. These results suggest that the fragmentation of seagrass meadows will become more pervasive as the human population continues to grow and estuarine development increases. Strategies to mitigate anthropogenic disturbances on seagrass meadow fragmentation could include prohibiting the construction of boat moorings and other artificial structures in areas where seagrasses are present or promoting environmentally friendly designs for marine infrastructure. This knowledge will support ongoing management actions attempting to balance coastal development and the conservation of seagrasses.

     

Effects of off‐bottom shellfish aquaculture on winter habitat use by molluscivorous sea ducks

• 1. Shellfish farming is an expanding segment of marine aquaculture, but environmental effects of this industry are only beginning to be considered.
• 2. The interaction between off‐bottom, suspended oyster farming and wintering sea ducks in coastal British Columbia was studied. Specifically, the habitat use of surf scoters (Melanitta perspicillata) and Barrow's goldeneyes (Bucephala islandica), the most abundant sea duck species in the study area, was evaluated in relation to natural environmental attributes and shellfish aquaculture.
• 3. The extent of shellfish farming was the best‐supported habitat variable explaining variation in surf scoter densities, and the only habitat attribute from the considered set that was a strong predictor of Barrow's goldeneye densities. In both cases, the findings indicated strong positive relationships between densities of sea ducks and shellfish aquaculture operations. These relationships are presumably the result of large numbers of wild mussels (Mytilus trossulus) that settle and grow on aquaculture structures and are preferred prey of these sea ducks.
• 4. Previous work has shown that aquaculture structures provide good conditions for recruiting and growing mussels, including refuge from invertebrate predators, which in turn provides higher densities of higher quality prey for sea ducks than available in intertidal areas. This offers a rare example in which introduction of an industry leads to positive effects on wildlife populations, which is particularly important given persistent declines in numbers of many sea ducks.

Copyright © 2008 John Wiley & Sons, Ltd.     

Nitrogen loading alters seagrass ecosystem structure and support of higher trophic levels

• 1. Anthropogenic‐derived nutrient inputs to coastal environments have increased dramatically worldwide in the latter half of the 20th century and are altering coastal ecosystems. We evaluated the effects of nitrogen loading on changes in macrophyte community structure and the associated fauna of a north temperate estuary. We found that a shift in primary producers from eelgrass to macroalgae in response to increased nutrient loading alters habitat physical and chemical structure and food webs. As nitrogen load increased we found increased macroalgal biomass, decreased eelgrass shoot density and biomass, decreased fish and decapod abundance and biomass, and decreased fish diversity.
• 2. The central importance of macroalgae in altering eelgrass ecosystem support of higher trophic levels is evident in the response of the ecosystem when this component was manipulated. Removal of macroalgae increased eelgrass abundance and water column and benthic boundary layer O₂ concentrations. These changes in the physical and chemical structure of the ecosystem with lower macroalgal biomass resulted in higher fish and decapod abundance and biomass.
• 3. Both a ¹⁵N tracer experiment and the growth of fishes indicated that little of the macroalgal production was immediately transferred to secondary consumers. δ¹⁵N values indicated that the most abundant fishes were not using a grazing food web based on macroalgae. Fish tended to grow better and have a greater survivorship in eelgrass compared to macroalgal habitats.
• 4. Watershed‐derived nutrient loading has caused increased macroalgal biomass and degradation and loss of eelgrass habitat, thus reducing the capacity of estuaries to support nekton.

Copyright © 2002 John Wiley & Sons, Ltd.     

Genetic diversity and connectivity patterns of harvested and aquacultured molluscs in estuaries from Asturias (northern Spain). Implications for management strategies

Estuaries are among the most important habitats of coastal areas. However, they are significantly affected by human activities worldwide, threatening their resources and the commercial uses depending on them. Fisheries and aquaculture are some of the main factors affecting the estuarine ecosystems today. In this work, we pursue the aims of genetically identifying the cultured and harvested oyster and razor clam species inhabiting Asturian estuaries (Eo, Ribadesella and Villaviciosa) and describing the genetic diversity and patterns of genetic connectivity between those species in these estuaries. The results revealed the almost complete dominance of the introduced Crassostrea gigas as the species that supports the oyster's production in Asturias with a striking diversity of gene pools in wild environments (Ría de Villaviciosa and Ribadesella) which significantly exceeds the diversity found in the hatcheries seeds commonly used for culturing. Moreover, we detected two different species of Ensis sp. inhabiting the Asturian estuaries: Ensis ensis inside Ría del Eo and Ensis directus, an invasive species, in Ría de Villaviciosa. Significant genetic differentiation between estuaries for the exotic oyster C. gigas and also for the native razor clam Solen marginatus were found. These results suggest Asturian estuaries are not a single management unit for some species and thus prevention must be taken for avoiding intentional or human‐mediated translocations among them. Biodiversity monitoring for discovering newcomer invasive species, measures for environmental recovery of these ecosystems and strict controls to avoid increasing of harvesting pressures are also a necessity to improve the management of these relevant ecosystems.     

河口水域鱼类生境质量评价方法研究进展

河口水域是鱼类重要的栖息生境, 在渔业资源的可持续发展中占据重要地位。开展河口水域生境质量的评价研究, 对了解河口水域的生境功能现状以及提供科学管理依据具有重要意义。本文对河口水域鱼类生境质量评价的研究方法及应用进展进行综述, 主要集中在 3 个方面: (1)基于鱼类数量分布特征: 通过鱼类的数量分布特征与环境因子之间的相关关系, 探究鱼类物种的适宜生境分布格局; (2)基于鱼类生存表现特征: 筛选鱼类生活史各阶段的生存表现特征指标, 对不同功能类型的生境进行质量评价; (3)基于鱼类的群落结构特征: 通过构建鱼类群落评价指数, 对河口水域鱼类生境质量进行综合评价。对河口水域鱼类生境质量的评价研究有助于深入了解河口渔业生态功能的变化机制, 并可为合理管控河口沿岸的人类活动、研发河口水域生境质量监测预警技术、科学开展河口生境保护和修复工作提供理论依据。     

Evaluation of carrying capacity for shrimp pond culture with integrated bioremediation techniques

The integrated multi‐trophic aquaculture (IMTA) is a semi‐artificial habitat optimization ecosystem by co‐culture species from multiple trophic levels, in which farm waste produced by species of a higher trophic level is a nutrition source for species of a lower trophic level. However, in system construction it is essential to distinguish the roles of aquaculture organisms from different trophic levels and optimize the aquaculture capacity allocation. With this objective, a carrying capacity evaluation model for shrimp culture with integrated bioremediation techniques was developed, and the efficiency to repair the aquaculture pond environment was evaluated. Scenario simulations were conducted to assess the shrimp culture capacity for optimal economic and ecological benefits. The sensitivity analysis of the model indicated that changes in bivalve biomass had no significant impacts on the concentration of total nitrogen (TN) in the system, and macroalgae were more sensitive to the changes in TN than biofilters did. In conclusion, 1,500,000 Litopenaeus vannamei co‐cultured with 15,000 kg Crassostrea gigas and 1,125 kg Gracilaria lemaneiformis per hectare would bring maximum integrated benefit, and the use of integrated bioremediation techniques can make shrimp pond culture a virtuous cycle incorporating both production and restoration.     

Recruitment and Commercial Seed Procurement of the Blue Mussel Mytilus edulis in Maine

A thorough understanding of recruitment in the blue mussel is necessary if the new industry is to maximize seed procurement without impinging upon other fisheries. Larval appearance is a relatively precise event in Maine, cued to early summer water temperature of 10–12 C and, apparently, full moon spawning events. Mussel larvae are more abundant on the flood tides indicating inshore and estuarine retention, although this retention relates to the morphometry and relative energy of the system. Webb Cove, a wide embayment with maximum sample station current velocity of 0.2 m/s, showed a random ebb tide vs. flood tide larval distribution; the narrow, long Damariscotta River estuary with 0.35 m/s current velocity showed a two-fold flood tide larval enhancement and the Jordan River with 1.5 m/s current velocities showed up to a 14-fold flood tide enhancement of mussel larvae and bysally drifting juveniles. Thus certain Maine estuaries may act as larval traps, providing areas of concentrated settlement and seed abundance. Primary setting normally begins with a large initial pulse in June followed by one or more secondary pulses throughout the summer. Secondary settlement (reattachment of bysally drifting juveniles) occurs at lower levels throughout the year, especially in late July and early August. Maximum attachment of larvae and juveniles occurs during periods of maximum current velocity. Extensive eelgrass beds at the mouths of some estuaries (i.e., Jordan River) may be the sites of extensive primary and secondary setting. Great Eastern Mussel Farms, the industry component, guided by these studies, is testing the deployment of live and shell mussel cultch to develop and optimize a new seed procurement system.     

Land‐based and climatic stressors of mangrove cover change in the Auckland Region,New Zealand

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才女虫属复合体的研究进展

才女虫属复合体（Polydora Complex）是典型的底质摄食者,多数种类栖居于潮间带、海湾、河口等近岸水域。其中一些种类是贝类上常见的多毛类寄生虫,能够钻入贝类的壳内营寄生生活,阻碍宿主的生长发育,感染严重时会导致贝类的大量死亡,是严重危害贝类养殖业发展的主要寄生虫类之一。文章从才女虫属复合体的形态分类、分子系统发育、栖居习性、生殖方式、幼体发育等5个方面综述才女虫属复合体的研究现状以及未来趋势。     

Fatty Acid Composition of U.S. West Coast Albacore Tuna (Thunnus alalunga) and the Effects of Canning and Short-Term Storage

ABSTRACT

Changes in the fatty acid composition of 13 bled and blast-frozen U.S. West Coast albacore tuna (Thunnus alalunga) were determined following custom-canning and 5 weeks of canned storage. In accordance with typical custom-canning procedures, no additional packing materials were used, and the product did not undergo a precooking step. Raw albacore tuna was found to be rich in n-3 polyunsaturated fatty acids (PUFAs), with an average of 9.1% (% wt of total fatty acids) EPA and 33.8% DHA. Canning and short-term storage did not cause major fluctuations in the fatty acid profiles of the albacore tuna, with no significant changes in the total fractions of saturated fatty acids (30–31%), monounsaturated fatty acids (19%), PUFAs (50%), or n-3 PUFAs (46–47%). On a tissue weight basis, U.S. West Coast albacore tuna was found to contain high levels of total n-3 PUFAs, with 3.3 g/100 g tissue in raw tuna and 4.0–4.1 g/100 g tissue in products that were canned and stored for 5 weeks.     

<Emphasis Type="Italic"> Xenostrobus securis </Emphasis>(Lamarck, 1819) (Mollusca: Bivalvia): first report of an introduced species in Galician waters

The presence of the non-indigenous species, the black-pygmy mussel Xenostrobus securis, is reported here for the first time in an intense shellfish farming area off Galicia (NW Spain). Very high concentrations of this mytilid bivalve have colonized estuarine waters located at the inner part of the Ria de Vigo. The invasive role of X. securis is discussed in the context of the wide ecological tolerance of the species and the recent finding of settlements of this species on numerous colonies of the economically-important blue mussel Mytilus galloprovincialis. The mode of introduction of the black-pygmy mussel is also discussed in relation to human management activities.     

A spatially explicit, individual-based model to assess the role of estuarine nurseries in the early life history of North Sea herring, Clupea harengus

Herring (Clupea harengus) enter and remain within North Sea estuaries during well‐defined periods of their early life history. The costs and benefits of the migrations between offshore spawning grounds and upper, low‐salinity zones of estuarine nurseries are identified using a dynamic state‐variable model, in which the fitness of an individual is maximized by selecting the most profitable habitat. Spatio‐temporal gradients in temperature, turbidity, food availability and predation risk simulate the environment. We modeled predation as a function of temperature, the optical properties of the ambient water, the time allocation of feeding and the abundance of whiting (Merlangius merlangus). Growth and metabolic costs were assessed using a bioenergetic model. Model runs using real input data for the Scheldt estuary (Belgium, The Netherlands) and the southern North Sea show that estuarine residence results in fitter individuals through a considerable increase in survival probability of age‐0 fish. Young herring pay for their migration into safer estuarine water by foregoing growth opportunities at sea. We suggest that temperature and, in particular, the time lag between estuarine and seawater temperatures, acts as a basic cue for herring to navigate in the heterogeneous space between the offshore spawning grounds at sea and the oligohaline nursery zone in estuaries.     

Fine‐scale habitat partitioning of Chilean and Peale's dolphins and their overlap with aquaculture

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