Ontogenetic movements of juvenile blacktip reef sharks: evidence of dispersal and connectivity between coastal habitats and coral reefs

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Frameworks for marine conservation — non‐hierarchical approaches and distinctive habitats

• 1. Conservation efforts have traditionally been directed to ‘flagship’ species (whales, seals, migratory birds, etc.) that capture public attention. Often these flagship species occupy distinctive habitats. Distinctive habitats appear to be distinguished because of anomalous physical structures and unique oceanographic processes occurring within them, whereas representative habitats are not notable in this way. Distinctive habitats are found in areas of various physical anomalies described primarily by temperature, chlorophyll and topography.
• 2. Several different kinds of distinctive habitats can be defined by their anomalous physical structures and oceanographic and biological processes. Species diversity may be either higher or lower in distinctive than in representative habitats. Distinctive habitats predominantly belong to a class of environments called ‘ergoclines’, and are typically associated with elevated resources at some ‘trophic level’.
• 3. These elevated resources may be either the product of true production (i.e. they are generated (in situ), or they are the product of physical accumulation due to circulation mechanisms. These processes lie at the heart of the ecology of distinctive habitats, and are fundamental to maintenance of ecosystem health, ecological integrity, distributions, abundances and recruitment of species, patterns of animal migrations, and potential or actual fisheries yields.
• 4. Conservation strategies need to examine the relationships between distinctive and representative habitats and species diversity. A strategy, leading from studies on flagship or other focal species, could have several advantages. It should rejuvenate the inherent appeal and significance of ‘species’ approaches to marine conservation, provide a rationale for human interest and a new foundation for examination of marine ecological interactions. It would also require a novel synthesis of relationships between ‘species’ and ‘spaces’ approaches to marine conservation by asking how we can take the best advantage of both approaches, rather than seeing them as in conflict.

Copyright © 2002 John Wiley & Sons, Ltd.     

Prioritizing localized management actions for seagrass conservation and restoration using a species distribution model

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枸杞岛海藻场优势种鱼类群体特征及其在不同生境中的差异

为了解枸杞岛岩礁不同底栖海藻分布的海藻场区域鱼类优势群体组成和分布特征,于2009年2月—2010年2月对枸杞岛海藻场和沙地生境的鱼类进行了逐月采样,对其中的鱼类优势种群组成、生物学特征和摄食规律作了比较。结果表明,以大型底栖海藻铜藻为优势种和以孔石莼等小型底栖海藻为优势种的海藻场鱼类全年优势种皆为褐菖鲉、斑头鱼和黄姑鱼。褐菖鲉群体具有近岸活动频繁、群体低龄和小型化、丰度年间变化大的特点,通过性成熟提前、雌性比例远高于雄性、摄食对象多样化的方式应对生存压力,维持对整个群体的补充。斑头鱼和黄姑鱼群体都具有低龄化现象,群体补充主要受洄游群体影响。3种鱼类因生活习性和摄食对象的不同,表现出个体间的生长差异。同时,由于发育不同阶段的食性转化、体型变化和来自上层捕食者的捕食压力,褐菖鲉和黄姑鱼会随着发育阶段的变化,表现出对不同生境的选择利用。斑头鱼食性较为稳定,其活动区域由主要的摄食对象麦秆虫所主导,主要栖息于海藻场生境。     

Geophysical approaches to the classification,delineation and monitoring of marine habitats and their communities

• 1. If marine environments are to be systematically protected from the adverse effects of human activities, then identification of the types of marine habitats and the communities they contain, and delineation of their boundaries utilizing a consistent classification is required. Human impacts on defined communities can then be assessed, the ‘health’ of these communities can be monitored, and marine protected areas can be designated as appropriate.
• 2. Schemes to classify habitats at local and regional scales, according to their geophysical properties, may identify different factors as determinants, and/or use them in different sequences in a hierarchical classification. We examined the reasons for these differences in local and regional applications of a global concept, and argue that a common set of factors could be applied in a defined and defensible sequence to produce a common hierarchy of habitat types among geographic regions.
• 3. We show how simple mapping and GIS techniques, based on readily available data, can lead to the identification of representative habitat types over broad geographic regions. We applied a geophysical framework first to the entire Canadian coastline and second to the Scotian Shelf of Atlantic Canada to establish broad scale marine natural regions and ‘seascapes’, respectively. This ecosystem level approach — which defines representative habitat types — is a fundamental prerequisite for many purposes. It can form the basis for further analyses including: definition of community types from habitat — community relationships; evaluation of the potential roles of focal species in marine conservation; evaluation of candidate marine protected areas; definition of unaffected reference areas against which the effects of human activities can be gauged; guidance for water quality monitoring studies; management of marine resources.

Copyright © 2003 John Wiley & Sons, Ltd.     

Predictive mapping for management and conservation of seagrass beds in North Carolina

An Erratum has been published for this article in Aquatic Conservation: Marine and Freshwater Ecosystems 12(2), 2002 577

• 1. This research extends techniques of predictive mapping from their application in terrestrial environments to marine landscapes by investigating the relationship between seagrass and hydrodynamics in Core Sound, North Carolina, USA.
• 2. An empirically derived logistic multiple regression model and a Boolean logic suitability model were used to produce several predictive map products, including: susceptibility of seagrasses to storms, probability of seagrass cover, and suitability of areas for restoration of seagrasses. A visual comparison between these maps and conventional seagrass polygon maps allows for a discussion of ‘field’ versus ‘object’ mapping, and the ramifications for management based on different cartographic techniques.
• 3. The predictive method used here showed that only a small portion (19%) of the seagrass bed in the study area would be expected to have a high probability of seagrass coverage. The majority of the seagrass habitat in the study area was predicted to have less than 50% probability of seagrass cover. In addition, 16% of the nearly 2000 ha of seagrass within the study area were predicted to be highly susceptible to acute storm events. Moreover, using a conservative set of site selection criteria, only 7% of the study area encompassed by seagrass habitat was predicted to have a high probability of successful restoration if injured.
• 4. This method provides for an inexpensive way to scale‐up from high‐resolution data to a coarser scale that is often required for conservation and management.

Copyright © 2001 John Wiley & Sons, Ltd.     

Implications of nutrient enrichment for the conservation and management of seagrass Zostera muelleri meadows

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The importance of bare marine sedimentary habitats for maintaining high polychaete diversity and the implications for the design of marine protected areas

• 1. Bare intertidal sedimentary habitats have received relatively little attention compared with their neighbouring vegetated habitats. An ecological comparison of benthic faunal assemblages inhabiting tropical intertidal seagrass beds and bare sediments has been made to assess the faunal similarity between the two habitats in south‐east Asia.
• 2. The poorly developed taxonomy of most invertebrate taxa in the region precluded the full identification of many faunal groups. Only the polychaetes — which accounted for 76% of all the macrofaunal organisms collected — were identified to the lowest possible taxonomic level, yielding 177 nominal species belonging to 35 families. Ecological analyses suggested that although each habitat had a distinct polychaete assemblage, there were few differences between habitats based on a range of calculated assemblage diversity metrics.
• 3. Further analyses were applied to the data to test the performance of three strategies for optimizing the selection of sites for inclusion in potential marine protected areas. Strategies were based either on the total number of species, the number of rare or endemic species, or on the level of species richness (used as a surrogate for community structure).
• 4. All three strategies consistently captured above average numbers of species at most levels of conservation intensity. The merits of each strategy are considered in turn.

Copyright © 2009 John Wiley & Sons, Ltd.     

Seasonal distribution of the Indo-Pacific humpback dolphins: Implications for coastal habitat management

1. Organisms utilize suitable habitat patches wherein they optimize fitness. For marine megafauna such as cetaceans, foraging is generally the explanation for their utilization distribution. However, an explicit link between cetaceans' distribution and spatio-temporal pattern of food resource is usually lacking.
2. The Indo-Pacific humpback dolphin (Sousa chinensis; VU listed in the IUCN Red List) inhabits the coastal waters from south-east China to eastern India. Seasonal distribution of the humpback dolphin was explored in the northern Beibu Gulf, China. Sightings of the humpback dolphin were systematically collected at monthly intervals from 2012 winter till 2018 spring and used to derive distribution patterns from kernel density estimates. Satellite remotely sensed net primary productivity (NPP) and bathymetry were used to present oceanographic characteristics in the study region.
3. Seasonal variations were observed in oceanographic characteristics and spatial distribution of the humpback dolphin. Although the core distribution area of the humpback dolphin showed seasonal expansion and contraction, it had consistently higher NPP and shallower depth than the survey range throughout the seasons.
4. Our findings indicate a clear profile of these two oceanographic characteristics (i.e. NPP and bathymetry) in the humpback dolphin's core distribution area. Food resource utilization could play an important role in the humpback dolphin's distribution within the study site. The seasonal dynamics imply that not only food abundance, but also efficiency in accessing/capturing the prey may affect distribution of the humpback dolphin.
5. In the study site, human activities that can change regional topography and productivity of the coastal water through land reclamation, dredging, sand mining and bottom trawling, should be mitigated, regulated or avoided. Proactive conservation should incorporate catchment management of the main rivers to address potential sediment and nutrient load into the estuary to protect local habitat configuration in terms of NPP and bathymetry.

     

Seasonal changes in distribution and abundance of euphausiids in the coastal area of north-eastern Japan

ABSTRACT:   Seasonal changes in distribution and abundance of euphausiids off south-eastern Hokkaido (41°−43°N), Sanriku (38°−41°N), and Joban (36°−38°N) were investigated using cylindrical-conical nets every two months from March 1997 to February 1998. Twenty-six species of seven genera of euphausiids occurred during the survey. Among them, subarctic-transitional Euphausia pacifica was the most abundant throughout the year in coastal waters, as their relative contribution to the total abundance of euphausiids was 89–92%. This species occurred in each coastal water throughout the survey and was abundant from winter to early summer (February–June) off Sanriku and Joban and in autumn in south-eastern Hokkaido. Thysanoessa inspinata occurred off south-eastern Hokkaido and Sanriku throughout the survey, mainly in spring (April) but rarely occurred off Joban. Three other subarctic Thysanoessa species occurred mainly off south-eastern Hokkaido from winter to spring. Conversely, warm- and transitional-water epipelagic species occurred exclusively off Sanriku and Joban in autumn. The characteristics of seasonal distributional patterns of euphausiids are discussed in relation to the spatial and temporal changes of oceanographic conditions and several predators off north-eastern Japan.     

广东沿岸牡蛎体Cd含量及时空分布特点

根据 198 9～ 1997年广东沿岸 12个采样点近江牡蛎 (CrassostrearivularisGould)体Cd的测定数据和有关历史资料 ,分析了广东沿岸牡蛎体Cd含量与时空分布特点。所有牡蛎体样品均检出Cd ,含量为( 0 .0 8～ 7.81)× 10 - 6,总平均值为 1.92× 10 - 6。粤东与粤西沿岸除个别样品外 ,绝大部分Cd含量均远低于评价标准 ,而珠江口沿岸样品的超标率则达到 2 5%。牡蛎体Cd含量的空间分布呈珠江口 >粤西 >粤东。1989～ 1997年 ,牡蛎体Cd含量的年际变化呈双峰分布 ,次高值和最高值分别出现在 1992年和 1995年 ,其余年份虽有波动 ,但无显著差异。     

The application of biogeographical zonation and biodiversity assessment to the conservation of freshwater habitats in Great Britain

1. Twelve biogeographical zones for freshwater habitats in Great Britain were derived, using detrended canonical correspondence analysis of data on climate, relief, geology, soils and land use, in conjunction with occurrence data for more than 300 native freshwater species. 2. The taxonomic groups used were aquatic macrophytes, dragonflies, freshwater molluscs, amphibians and selected leeches, water beetles and crustaceans. The computer database of the Institute of Terrestrial Ecology's Biological Records Centre was used as the principal source of species data. 3. Within each of the 12 biogeographical zones, 10×10 km square ‘hotspots’ for species richness and rarity were identified. 4. The significance of this work for the conservation of freshwater habitats and species in Great Britain is discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Using aerial photography for identification of marine and coastal habitats under the EU's Habitats Directive

• 1. Implementation of the E.U. Habitats Directive requires information on the distribution, abundance and area covered by the habitats listed in Annex I of the Directive.
• 2. In Finland, 21 of these habitats occur in marine and coastal areas. The demand for spatial information of these habitats is increasing, so rapid and relatively inexpensive mapping methods are needed.
• 3. This study examines the identification of 15 habitats using high altitude black and white aerial photographs. Our goal was to find out how well these habitats could be identified using these types of photographs. We used a test group of 34 persons who were given only brief instructions on how to identify the habitats prior to the test. Their results were compared to a set of field data from an archipelago area at the entrance of the Gulf of Finland, in August 1999 and autumn 2000.
• 4. The test group identified sandy beaches, lagoons, submerged sandbanks and cliffs with an accuracy of 82%, 71%, 66% and 65%, respectively. The main reasons for these high accuracy percentages were apparently the high contrast and/or easy delineation of the habitat from the surrounding areas.
• 5. Reefs, wooded dunes and submerged reefs were identified with an accuracy of 39%, 44% and 45%, respectively. The remaining habitats were less precisely identified, apparently due to their small size or poor contrast to the surrounding areas.
• 6. High altitude aerial photographs are shown to be a useful tool for identifying several of these habitats and can be used as a complement to field mapping methods, GIS methods and other remote sensing techniques. The use of high altitude photographs for monitoring change is discussed.

Copyright © 2002 John Wiley & Sons, Ltd.     

南麂列岛海洋自然保护区的虾类种类组成和数量分布

根据2013年11月、2014年2月、5月、9月在南麂列岛海洋自然保护区开展渔业资源调查所获得的虾类调查资料,将生物量作为虾类资源分布的数量指标,对南麂列岛海洋自然保护区的虾类种类组成、数量分布、优势种变化,及其与环境因子的关系等进行了研究。结果如下:(1)调查海域共鉴定出虾类25种,隶属于9科17属,虾类生物量各季节由高到低依次为夏季(32358.0 g)、秋季(13033.0 g)、冬季(3938.6 g)、春季(3635.6 g);(2)虾类数量分布季节变化明显,且岛礁区偏外的开阔海域虾类生物量比较高;(3)不同季节优势种更替较显著,春季优势种为日本鼓虾、鲜明鼓虾和细巧仿对虾,夏季优势种为哈氏仿对虾和中华管鞭虾,秋季优势种为中华管鞭虾、细巧仿对虾和哈氏仿对虾,冬季的优势种为细巧仿对虾、脊尾白虾、鲜明鼓虾和日本鼓虾;(4)水深对虾类生物量分布影响明显,各季节虾类生物量与环境因子相关性关系变化较大。结论认为,南麂列岛调查海域的虾类种类以季节性的广温广盐性种类为主;主要优势种生物量夏秋两季明显高于冬春两季,可能是因为大量虾类冬春季离开该海域去其他海域越冬繁殖,而到了夏秋季则回到该海域产卵、育肥和栖息;在夏、秋、冬季沿岸区虾类生物量高于岩礁区,可能因为虾类一般生活于有利于索饵、成长的泥沙底质沿岸区;优势种更替显著与主要优势种生长周期与虾类个体大小特征有关;南麂列岛海域虾类生物量与环境因子关系复杂与该海域多变的温度盐度、复杂区系特点有关;虾类生物量分布随水深变化分布明显,这主要是由于调查海域主要优势种虾类活动范围与水深有关。     

Spatial and temporal diversity of fish captured by light traps in various habitats in coastal waters in the oldest marine protected area in Vietnam and its implications for conservation

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温台渔场3种经济鱼类体长频次分布与采样量间关系的比较

为了量化和比较温台渔场3种经济鱼类体长频次分布与实际收集的观测样本之间的关系,本研究基于收集的样本体长信息能够反映研究区域鱼种真实的体长组成信息这一假设,根据春、夏两季在温台渔场采集的3种经济鱼类(小黄鱼、银姑鱼和龙头鱼)的体长数据,利用计算机模拟方法设计了不同的样本量方案.利用均方差异值(mean square di...     

基于渔业调查的利文斯顿岛西南部2012年秋冬季南极大磷虾体长时空分布

基于南极磷虾渔业科学观察员收集的南极大磷虾(Euphausia superba)体长数据,将研究区域划分成经纬度10'×10'小尺度单元,分析了利文斯顿岛西南部水域2012年秋冬季南极大磷虾体长分布的时空特征。结果表明,10个单元的平均体长范围为35.3～51.0 mm,其中最小体长为23.1 mm,最大体长为61.0 mm,各单元间体长分布存在显著性差异。由秋末转至冬初,南极大磷虾平均体长及优势体长范围均呈逐渐减小趋势。14～16时和22～24时南极大磷虾个体较小,而4～6时、8～10时以及20～22时的南极大磷虾则以大个体为主。一半以上(72%)的样本分布于40～80 m水层。80 m以深水层,南极大磷虾个体均大于38 mm。随着海区水深的增加,南极大磷虾平均体长逐渐减小,且南极大磷虾体长组成在不同水深海区呈现不同的分布模式。     

东海北部近海夏季虾类组成及其数量分布

依据2007年7月和2008年6月东海北部近海(123°~124°30′E、30°~32°N)桁杆拖虾定点调查资料,对夏季东海北部近海虾类资源的种类组成、数量分布特征进行了研究分析。夏季该水域共出现虾类18种,隶属于7科11属。其中6月份的优势种有鹰爪虾(IRI=7 485)、葛氏长臂虾(IRI=2 121)、脊腹褐虾(IRI=819.1)和戴氏赤虾(IRI=765.5),7月份的优势种有鹰爪虾(IRI=5 637)、葛氏长臂虾(IRI=451.1)、须赤虾(IRI=3 184)和戴氏赤虾(IRI=868.7)。夏季东海北部近海虾类资源群体重量密度分布主要呈现中部较少而东西两端分布较多的态势,不同优势种类的分布特征不同,鹰爪虾分布于整个调查海域,底温为12.1~21℃,底盐为31.1~34.6;脊腹褐虾主要分布于调查海域的东北部,底温为12.1~18℃,底盐为31~32。     

Size influences the spatial distribution and fish‐aggregating device use of five Mediterranean fish species

Abstract Fish‐aggregating devices are floating objects used worldwide to improve pelagic fishery yield. Fish‐aggregating devices use the natural attraction exerted by floating objects on juveniles and adults of both pelagic and demersal fish. In this study, it was hypothesised that fish change their degree and type of interaction with moored floating objects depending on size. This is because fishes in early life stage remain close to floating objects, using them as a shelter, but as they grow they move further away from floating objects spending their time swimming to seek food. To test this hypothesis, the spatial distribution and habitat use of five Mediterranean fish species were quantified. The results enabled the hypothesis to be accepted for all species, except Balistes carolinensis Gmelin. For this species, a shelter from predator model was applicable, but for the other species, the generalised meeting point model was more adaptable.     

环境与摄食对山东省近海鱼礁区不同体长许氏平鲉分布的影响

为研究环境与摄食因素对人工鱼礁区不同体长许氏平鲉分布的影响,采用2017—2018年山东省近岸3处鱼礁区环境和渔业资源的调查数据,利用变异系数CV均值将样本的体长分为10组,每组体长间隔为33 mm,并使用Bray-Curtis相似性指数比较不同海域许氏平鲉体长组成的相似性;运用去趋势对应分析(DCA)、典范对应分析(CCA)分析各环境要素对不同体长组许氏平鲉分布的影响;运用胃含物分析法分析许氏平鲉的食物组成。结果显示,西霞口与长岛鱼礁区样本体长组成相似性指数为70.66%,前三岛鱼礁区与西霞口鱼礁区、长岛鱼礁区的相似性指数较低,分别为54.94%和59.46%;大体长(299～365mm)许氏平鲉的分布与水深、水质指数(WQI)和化学需氧量(COD)相关性较大,喜好水深较深、营养丰富的水域;小体长(35～200 mm)许氏平鲉喜好水深较浅,水质好的水域。大体长(200～365 mm),高龄(2～3龄)的个体主要摄食鱼类、虾类和蟹类,优势饵料为鱼类(IRI为65.94%);小体长(35～200 mm),低龄(0～1龄)的个体主要摄食虾类和蟹类,优势饵料为虾类(IRI为45.69%)。研...