Natural Oyster Reefs Research Articles

江苏海门蛎岈山牡蛎礁生态现状评价

PDF HTML阅读 XML下载 导出引用 引用提醒 江苏海门蛎岈山牡蛎礁生态现状评价 DOI: 10.5846/stxb201510102048 作者: 作者单位: 农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,农业部东海与远洋渔业资源开发利用重点实验室 中国水产科学研究院东海水产研究所 上海,江苏海门蛎岈山国家级海洋公园管理处 江苏海门,江苏海门蛎岈山国家级海洋公园管理处 江苏海门,江苏海门蛎岈山国家级海洋公园管理处 江苏海门,江苏海门蛎岈山国家级海洋公园管理处 江苏海门,江苏海门蛎岈山国家级海洋公园管理处 江苏海门,江苏海门蛎岈山国家级海洋公园管理处 江苏海门 作者简介: 通讯作者: 中图分类号: 基金项目: 江苏海门蛎岈山国家级海洋公园管理处项目；中央级公益性科研院所（东海水产研究所）基本科研业务费项目（2014G01，2015M01）；国家公益性行业（农业）科研专项经费项目（201303047）；国家自然科学基金面上项目（31170508） Ecological status of a natural intertidal oyster reef in Haimen County, Jiangsu Province Author: Affiliation: Key Lab of East China Sea and Marine Fishery Resource Exploitation and Utilization, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Science, 200090, Shanghai, China,,,,,,,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要: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（P < 0.05）。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。 Abstract:Oyster reefs are important coastal habitats because they provide ecosystem services such as water filtration, habitat provision, shoreline stabilization, and nutrient retention. The Liyashan oyster reef is located inshore of the Dongzhao Port, Haimen County, Jiangsu Province, and it is a natural intertidal reef. The oyster reef supports abundant species and high fishery production, and it is a major spawning ground for the roughskin sculpin, Trachidermus fasciatus, which is listed as a second-grade state protection animal. However, there is limited information on the ecological status of the natural oyster reef. In this study, we mapped the reef footprint and monitored oyster populations (species, density, biomass, size-frequency, body condition, genetic diversity, and parasite infection) at the Liyashan oyster reef on the basis of field investigations conducted in 2013 and 2014 and compared the metrics to those of farmed oysters. Aerial photos obtained using an unmanned plane indicate that the natural oyster reef is composed of 750 intertidal reef patches, and the area of a patch ranges from 0.98 m2 to 16330 m2. The total area of the intertidal reef is approximately 0.201 km2. However, the aerial footprint of the natural reef has declined by approximately 39% in the past decade because of sedimentation. Mean cover for live oysters was 66%, and mean densities of the oyster Crassostrea sikamea were between 2199 and 2894 ind./m2. The percentage of oyster spats with respect to size-frequency distribution was greater in September than in May, showing high recruitment of oyster larvae in the summer. Mean flesh content, condition index, and gonad index of C. sikamea were (32.15±1.80)%, (9.76±0.95)%, and (600±116) mg/g, respectively. These values were significantly lower at the Liyashan natural oyster reef than at nearby aquaculture sites ((36.50±2.34)%, (15.24±1.04)%, and (1013±82) mg/g, respectively) in Xiangshan Bay, Zhejiang Province. Haplotype diversity and nucleotide diversity index of the C. sikamea population at Liyashan were 0.119 and 0.00028, respectively, and were greater than the values observed at the aquaculture sites. The oyster population had been slightly infected by the parasite Haplosporidium nelsoni, and the infection frequency (17.2%) was lower at the natural reef than at the aquaculture sites (47.3%). The natural oyster reef is rapidly degrading because of heavy sedimentation. The oyster population at the reef had lower body condition, greater genetic diversity, and lower gonad index and parasite infections than those at the aquaculture sites. To protect this important biogenic reef, greater restoration efforts should be initiated to promote the oyster population and reef functions by supplementing hard substrates. 参考文献 相似文献 引证文献

Maximizing oyster-reef growth supports green infrastructure with accelerating sea-level rise.

Within intertidal communities, aerial exposure (emergence during the tidal cycle) generates strong vertical zonation patterns with distinct growth boundaries regulated by physiological and external stressors. Forecasted accelerations in sea-level rise (SLR) will shift the position of these critical boundaries in ways we cannot yet fully predict, but landward migration will be impaired by coastal development, amplifying the importance of foundation species’ ability to maintain their position relative to rising sea levels via vertical growth. Here we show the effects of emergence on vertical oyster-reef growth by determining the conditions at which intertidal reefs thrive and the sharp boundaries where reefs fail, which shift with changes in sea level. We found that oyster reef growth is unimodal relative to emergence, with greatest growth rates occurring between 20–40% exposure, and zero-growth boundaries at 10% and 55% exposures. Notably, along the lower growth boundary (10%), increased rates of SLR would outpace reef accretion, thereby reducing the depth range of substrate suitable for reef maintenance and formation, and exacerbating habitat loss along developed shorelines. Our results identify where, within intertidal areas, constructed or natural oyster reefs will persist and function best as green infrastructure to enhance coastal resiliency under conditions of accelerating SLR.

Archaeological Site or Natural Marine Community? Excavation of a Submerged Shell Mound in Ninigret Pond, Rhode Island

ABSTRACTSubmerged shell midden sites and natural shell deposits can have similar characteristics and can be difficult to distinguish archaeologically. We excavated two test units from a large (at least 35 m×70 m) submerged shell mound in Fort Neck Cove in southern Rhode Island to assess whether it was natural or cultural in origin. This mound had been recognized as a potential archaeological feature as early as the 1970s. Excavation, radiocarbon dating, and subsequent laboratory analysis of excavated materials suggest that the mound was a natural oyster reef rather than a submerged archaeological site. No artifacts were found; there was no clear evidence for human modification of any shells; small species that would not have been targeted as food were present; and δ13C values of oyster shells from the mound were consistent with freshwater input into their growth environment, suggesting that they grew in an estuarine environment that did not exist prior to the inundation of the ponds. The stratigraphically oldest radiocarbon date we could obtain (430–190 cal BP, 2σ range), from 70 cm below the pond floor, placed deposition of shells at least 3,000 years after the inundation of the pond. The excavation methods that we used and the process of testing, irrespective of whether the feature is cultural, are valuable contributions to the methodological literature on submerged site archaeology and help provide insight for other researchers working to discern natural from cultural shell midden sites.

Provision of ecosystem services by human-made structures in a highly impacted estuary

Water filtration is one of the most important ecosystem services provided by sessile organisms in coastal ecosystems. As a consequence of increased coastal development, human-made shoreline structures (e.g., docks and bulkheads) are now common, providing extensive surface area for colonization by filter feeders. We estimate that in a highly urbanized sub-tropical estuary, water filtration capacity supported by filter feeding assemblages on dock pilings accounts for 11.7 million liters of water h−1, or ∼30% of the filtration provided by all natural oyster reef throughout the estuary. Assemblage composition, and thus filtration capacity, varied as a function of piling type, suggesting that the choice of building material has critical implications for ecosystem function. A more thorough depiction of the function of coastal ecosystems necessitates quantification of the extensive ecosystem services associated with human-made structures.

Biophysical Constraints on Optimal Patch Lengths for Settlement of a Reef-Building Bivalve

Reef-building species form discrete patches atop soft sediments, and reef restoration often involves depositing solid material as a substrate for larval settlement and growth. There have been few theoretical efforts to optimize the physical characteristics of a restored reef patch to achieve high recruitment rates. The delivery of competent larvae to a reef patch is influenced by larval behavior and by physical habitat characteristics such as substrate roughness, patch length, current speed, and water depth. We used a spatial model, the “hitting-distance” model, to identify habitat characteristics that will jointly maximize both the settlement probability and the density of recruits on an oyster reef (Crassostrea virginica). Modeled larval behaviors were based on laboratory observations and included turbulence-induced diving, turbulence-induced passive sinking, and neutral buoyancy. Profiles of currents and turbulence were based on velocity profiles measured in coastal Virginia over four different substrates: natural oyster reefs, mud, and deposited oyster and whelk shell. Settlement probabilities were higher on larger patches, whereas average settler densities were higher on smaller patches. Larvae settled most successfully and had the smallest optimal patch length when diving over rough substrates in shallow water. Water depth was the greatest source of variability, followed by larval behavior, substrate roughness, and tidal current speed. This result suggests that the best way to maximize settlement on restored reefs is to construct patches of optimal length for the water depth, whereas substrate type is less important than expected. Although physical patch characteristics are easy to measure, uncertainty about larval behavior remains an obstacle for predicting settlement patterns. The mechanistic approach presented here could be combined with a spatially explicit metapopulation model to optimize the arrangement of reef patches in an estuary or region for greater sustainability of restored habitats.

Habitat use of Intertidal Eastern Oyster (Crassostrea virginica) Reefs by Nekton in South Carolina Estuaries

ABSTRACT The majority of recent studies investigating the habitat value of intertidal oyster reefs have compared the nektonic assemblages on natural oyster reefs, salt marshes, mud bottom, and subtidal oyster shell habitats using methods that involve some degree of habitat disturbance. The current study used a novel, non-destructive sampling approach involving the deployment of a drop net around study plots to compare the nektonic assemblages associated with intertidal oyster reefs (natural and enhanced) with those of neighboring soft sediment habitats at 3 sites in South Carolina. At each site, the nektonic organisms collected on a reef plot were compared with those collected on an adjacent control plot lacking a structurally complex habitat. Nekton abundance was significantly higher on the reef plot compared with the control plot at all 3 sites. Nekton abundance also varied among seasons, with the greatest numbers occurring during summer compared with spring and fall. Notably, grass shrimp (Palaemonetes...

Do Small, Patchy, Constructed Intertidal Oyster Reefs Reduce Salt Marsh Erosion As Well As Natural Reefs?

One ecological service that oyster reefs provide is stabilization of shorelines through reduced wave energy and erosion from boat traffic, storms, and predominant wind direction. Additionally, increasing sedimentation can enhance the growth of emergent marsh vegetation which further stabilizes unconsolidated sediments. A 21 mo study of constructed (with only 30-35% coverage) and natural oyster reefs in 3 bayous in the Grand Bay National Estuarine Research Reserve (NERR) suggested constructed reefs benefit this retrograding deltaic ecosystem. The marsh edge adjacent to all constructed reefs was less eroded (mean = 0.043 m) than edges adjacent to natural reefs (mean = 0.728 m), although all natural and constructed sites, regardless of bayou, illustrated large variations in marsh edge growth. The marsh edge in constructed sites in one bayou retreated more than in the other bayous, most likely due to its coarser sediments, greater boat traffic, and its apparent higher energy location within the landscape. By the end of this study, the ecological function of constructed oys- ter reefs in all bayous, as measured by marsh edge erosion reduction, was equivalent or exceeded the function in nearby natural oyster reefs. The physical structure of the reef further served to reduce erosion and marsh loss and this approach may be useful for management of a retrograding deltaic estuarine ecosystem like the Grand Bay NERR.

Heat Shock Protein 70 Expression in Juvenile Eastern Oysters,Crassostrea virginica(Gmelin, 1791), Exposed to Anoxic Conditions

ABSTRACT Anoxic water events in conjunction with summer high temperatures are thought to be one of the causes of declines in natural oyster reefs on the eastern shore of Mobile Bay. Work is underway to determine whether tolerance to low oxygen can be selected for in hatchery-produced oysters. As a component of this work, the expression of heat shock protein 70 (HSP 70) was examined in control (normoxia) and anoxia-challenged juvenile oysters. Parental Eastern oysters, Crassostrea virginica were collected from 2 sites, Cedar Point Reef (CP), an area considered to have normoxic conditions, and White House Reef (WH), an area suspected to experience periodic anoxia. F1 generation oysters were produced from CP and WH parents that survived an anoxic exposure of 96 h. Control F1 generation oysters from both parental stocks not exposed to anoxia were also produced. The F1 generation oysters were subsequently exposed to anoxia or control normoxic conditions, and differences in expression of HSP 70 were examined. N...

AGE AND GROWTH OF WILD SUMINOE (CRASSOSTREA ARIAKENSIS, FUGITA 1913) AND PACIFIC (C. GIGAS, THUNBERG 1793) OYSTERS FROM LAIZHOU BAY, CHINA

Abstract Shell height at age estimates from Suminoe (Crassostrea ariakensis) and Pacific (C. gigas) oysters from a natural oyster reef in Laizhou Bay, China were compared with shell height at age estimates from triploid C. ariakensis of known age from the Rappahannock River, Virginia. C. ariakensis and C. gigas reach shell heights in excess of 76 mm (3 inches) within 2 years after settlement regardless of the source location. This fast growth appears to continue through at least age 4 or age 5 in wild individuals, because the growth trajectories for both species had not reached asymptotic height in the oldest individuals collected. Estimates of the asymptotic maximum height (SHmax) from fitted Von Bertalanffy (VB) growth models were greatest for Chinese C. ariakensis (244.0 mm, standard error of the mean [SE] 30.4) and near the maximum shell height (227.0 mm) measured at the time of collection. Maximum shell heights measured on live Chinese C. gigas (173.0 mm) and Rappahannock C. ariakensis (190.0 mm) wer...

HOW HABITAT DEGRADATION THROUGH FISHERY DISTURBANCE ENHANCES IMPACTS OF HYPOXIA ON OYSTER REEFS

Oysters are ecosystem engineers that create biogenic reef habitat important to estuarine biodiversity, benthic–pelagic coupling, and fishery production. Prevailing explanations for the dramatic decline of eastern oysters (Crassostrea virginica) during the last century overlook ecosystem complexity by ignoring interactions among multiple environmental disturbances. To explain oyster loss, we tested whether (1) mortality of oysters on natural oyster reefs varies with water depth (3 m vs. 6 m), (2) harvesting by oyster dredges reduces the height of oyster reefs, and (3) bottom-water hypoxia/anoxia and reduction in reef height through fishery disturbance interact to enhance mortality of oysters in the Neuse River estuary, North Carolina, USA. The percentage of oysters found dead (mean ± 1 sd) during a survey of natural reefs in May 1993 was significantly greater at 6-m (92 ± 10%) than at 3-m (28 ± 9%) water depth. Less than one season’s worth of oyster dredging reduced the height of restored oyster reefs by ∼30%. During stratification of the water column in summer, oxygen depletion near the seafloor at 6 m caused mass mortality of oysters, other invertebrates, and fishes on short, deep experimental reefs, while oysters and other reef associates elevated into the surface layer by sufficient reef height or by location in shallow water survived. Highly mobile blue crabs (Callinectes sapidus) abandoned burrows located in hypoxic/anoxic bottom waters but remained alive in shallow water. Our results indicate that interaction of reef habitat degradation (height reduction) through fishery disturbance and extended bottom-water hypoxia/anoxia caused the pattern of oyster mortality observed on natural reefs and influences the abundance and distribution of fish and invertebrate species that utilize this temperate reef habitat. Interactions among environmental disturbances imply a need for the integrative approaches of ecosystem management to restore and sustain estuarine habitat.

The Benthic Macrofauna Associated with the Oyster Reefs of the James River Estuary, Virginia, U.S.A.

AbstractProductive, natural oyster reefs within the James River estuary, were quantitatively sampled for associated macrofauna for a year. The 192 samples yielded 142 taxa. Mean faunal density on these reefs ranged from 5,757 to 57,857 m−2. Over 770/0 of the individuals collected belonged to 11 taxa. The number of species and informational diversity (H') decreased up the estuarine gradient.The quality of available shell surface was deemed important in determining density. The spatial heterogeneity provided by the shell surface allowed development of a densely populated, diverse faunal assemblage which differs from soft‐bottom assemblages principally in quantitative aspects. The assemblage is not spatially or temporally homogeneous and undergoes significant changes in community structure both seasonally and along the estuarine gradient.

Location of the Mississippi Sound Oyster Reefs as Related to Salinity of Bottom Waters During 1973-1975

The relationship of producing natural oyster reefs of Mississippi Sound to the salinity regime of bottom waters is investigated. Extreme and average conditions were extracted from data taken at 87 stations over a 21-month period from June 1973 through February 1975. With one exception, the producing reefs were subjected tosalinity minimums of 2.0 to 4.0 parts per thousand (ppt), maximums of 18.0 to 22.0 ppt, with avcragc conditions being between 10.0 and 16.0 ppt. Salinity-suitable areas in the Sound not now inhabited by oysters are described.