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1.
    
  1. Cold‐water coral (CWC) ecosystems are long‐lived, slow‐growing and fragile, which makes them especially vulnerable to physical damage. In recent decades, CWCs have been severely threatened by fisheries, hydrocarbon extraction, pollution and other human activities.
  2. In the Mediterranean Sea, some investigations have been carried out on CWC ecosystems, mostly focused on their distributions within the central and eastern basins.
  3. Historical reports and fishermen's maps for the eastern Ligurian Sea (NW Mediterranean) from the 1960s document the occurrence of extensive banks of living CWC, mostly Madrepora oculata, between depths of 200 and 500 m.
  4. In 2013/2014, multibeam, side scan sonar (SSS) and remotely operated vehicle (ROV) surveys were carried out in that area, specifically in the Levante Canyon, to assess the occurrence, distribution and conservation status of CWC.
  5. The SSS and ROV showed numerous trawl tracks and small (10 cm high), dead, buried colonies at 300–500 m. Deeper, between 525 and 575 m, dense populations of living, 1 m high colonies of Madrepora oculata were found on the flanks of Levante Canyon. The deep sites showed colonies overturned or entangled by long‐line fishing activities.
  6. The discovery of new CWC banks not yet heavily damaged by fishing activities, suggests that urgent measures for conservation should be taken in the Mediterranean and worldwide. The present limitation of trawl‐fishing to above 1000 m depth, established by the General Fisheries Commission for the Mediterranean (GFCM) in 2005, seems to be ineffective, since CWCs are mostly located at less than 1000 m depth in the Ligurian Sea. A network of high‐seas/deep‐sea marine protected areas (MPAs) would favour a better strategy for protecting substantial areas of CWCs.
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2.
    
In a time of ever-increasing pressure on the coastal ocean and rising costs, the development of effective and efficient methods for assessing the health of marine ecosystems is becoming essential for continued conservation efforts. Taking advantage of technologies such as remotely operated vehicles (ROVs) may be a way of achieving this, but a quantitative check on the quality of ROV-derived data is necessary. Here, using coralline algae reefs (maerl beds) as a model habitat, we compared 3D seabed reconstructions obtained from structure-from-motion photogrammetry surveys from diver-held and ROV-mounted camera systems. We found that both approaches achieved satisfactory alignment and mm-scale resolution, allowing small-scale features and individual organisms in the maerl bed to be resolved. The higher quality camera system available to divers resulted in generally lower modelling errors, but the spatial extent of surveys was highly restricted. In contrast, although associated with a slightly higher error, we show that much larger areas can be surveys by ROVs—we reconstructed 11,285 m2 of seabed in just 400 min of ROV deployment time. Moving forward, we recommend that a hybrid survey approach is adopted: utilising ROV surveys for large-scale monitoring and diver surveys for higher detail insights that are informative for areas with highly complex and fine-scale morphologies (like coralline algae reefs). Here, even small changes in complexity can be indicative of habitat change, and associated species can be small in size so multiscale visual assessment is beneficial.  相似文献   

3.
    
  1. The characterization of benthic communities at the Burdwood Bank slope (≥200 m depth) is provided, comprising data from the marine protected area (MPA) Namuncurá II (created in December 2018), as well as from some deep bathyal surrounding areas in the Southwest Atlantic Ocean. This information was acquired during two research cruises with RV Puerto Deseado (Argentina) during 2016 and 2017.
  2. Marine animal forests were detected in the study area: coral gardens, mainly composed of alcyonaceans, were detected in the south and west of Burdwood Bank (MPA Namuncurá II) and neighbouring areas, whereas pennatulacean aggregations were detected in the north‐west of the plateau. The three‐dimensional structures of live but also dead corals provide substrate and refuge to many associated species. Benthic communities dominated by sponges were also recorded between 200 and 300 m in depth.
  3. Six sites that meet the characteristics of vulnerable marine ecosystems (VMEs) are reported.
  4. Conservation strategies applied to scarcely known austral Argentinean waters led to the establishment of a pioneer MPA (Namuncurá I). Following the management plan that aimed to establish the biodiversity of Namuncurá I and neighbouring areas, the area of protection has now been enlarged to include the southern slope of the bank (currently Namuncurá II), where marine animal forests were detected, at depths below 200 m. The data presented here provide empirical evidence to support the conservation value of the region.
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4.
    
  1. Marine managers are looking increasingly to marine protected areas (MPAs) to deliver benefits to fisheries; however, many of these MPAs have been established in order to address specific conservation objectives unrelated to fisheries management.
  2. This paper describes a small no‐take zone (NTZ) set up in the Clyde, Scotland, for conservation purposes, and examines its effect on the abundance of two commercially fished scallops, Pecten maximus and Aequipecten opercularis, 5 years after closure.
  3. Scallop fishing immediately outside the NTZ has continued since this closure, although at lower intensities, with overall landings in the Clyde and landings per unit area rising until 2013, suggesting a slight increase in regional abundance.
  4. There was neither a significant increase in adult scallop abundance within the NTZ nor evidence of the dispersal of adults into surrounding areas.
  5. Transient dynamics and the small size of the NTZ may have played a role in the lack of demonstrable scallop recovery. The practice of ‘selling’ small conservation MPAs in terms of meeting wider fisheries objectives is discussed in light of this result.
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5.
    
  1. Recently, several large marine protected areas (MPAs) have been established globally, and it is hoped that they will aid the recovery of populations of highly mobile, large pelagic species. Understanding the distribution of these species within MPAs is key to delivering effective management, but monitoring can be challenging over such vast areas of open ocean.
  2. Historical fisheries data, collected prior to MPA establishment, can provide an insight into the past distributions of target species. We investigated the spatial and temporal distribution of yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tuna catch using logbook data from the purse seine fishery in the British Indian Ocean Territory from 1996 to 2010, before it was established as an MPA in April 2010.
  3. Generalized additive models were used to predict tuna presence and relative abundance from fishing records in relation to temporal and environmental variables. Significant variables included sea salinity, temperature, and water velocity.
  4. Predictions from the models identified a distinct hotspot for large yellowfin tuna within the MPA, and areas of high predicted relative abundance of skipjack tuna. We recommend that these areas are used as focal points from which populations can be monitored and investigations into tuna residency time can occur, so that the effectiveness of the MPA in conserving highly mobile pelagic fish can be determined.
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6.
In 1997, the Bering Sea ecosystem, a productive, high-latitude marginal sea, demonstrated that it responds on very short time scales to atmospheric anomalies. That year, a combination of atmospheric mechanisms produced notable summer weather anomalies over the eastern Bering Sea. Calm winds, clear skies, and warm air temperatures resulted in a larger-than-normal transfer of heat to surface waters and the establishment of a shallow mixed layer. In spring, significant new production occurred below the shallow pycnocline over the Middle Shelf, depleting the subpycnocline nutrient reservoir that normally exists during summer. Following the depletion of nitrate and silicate from the system, a sustained (≥ 4 months) bloom of coccolithophores ( Emiliania huxleyi ) was observed – a phenomenon not previously documented in this region. Summer Middle Shelf Domain copepod concentrations were higher for some species in 1997 than in the early 1980s. Warmer surface water and lack of wind mixing also changed the basic distribution of hydrographic regimes on the south-eastern shelf and altered the strength and position of fronts or transition zones where apex predators seek elevated food concentrations. The Inner Front was well inshore of its normal position, and adult euphausiids (the primary prey of short-tailed shearwaters, Puffinus tenuirostris ) were unavailable at, and shoreward of, the front in autumn. High shearwater mortality rates followed the period of low euphausiid availability. Some, but not all, of these anomalous conditions re-occurred in 1998. These observations are another demonstration that the structure and function of marine ecosystems are intimately tied to forcing from the atmosphere. Alteration of climatological forcing functions, expressed as weather, can be expected to have large impacts on this ecosystem and its natural resources.  相似文献   

7.
    
  1. Detailed knowledge about the distribution of species in need of protection is required for the management of Marine Protected Areas, a major tool to reduce marine biodiversity loss. Such knowledge is deficient for most marine invertebrates.
  2. Axinella polypoides is a marine sponge included on the list of protected species by the Barcelona Convention (1976) and the Bern Convention (1987). This large and erect species has an important ecological role in habitat forming and benthic–pelagic coupling.
  3. Bathymetrical, geographical and ecological data over the last 60 years were collated from publications and reports, together with new surveys to assess the distribution and protection status in Liguria of A. polypoides. It identified a more widespread distribution than previously thought, which points at a general need for dedicated investigations on the occurrence of species that require protection.
  4. Bathymetrical distribution was trimodal, with peaks corresponding to different geomorphological settings: coastal cliff bases (around 38 m depth), inner shelf shoals (52 m) and rocks amidst coarse sediment on the outer shelf (79 m). Density was significantly greater at the shallowest depths. The species was mostly found in the coralligenous biocoenosis, in association with other characteristic species or forming a monospecific facies.
  5. On (sub)vertical cliffs, A. polypoides often exhibited an unusual cane shape, rather than the typical bushy morphology, thus causing confusion with the congeneric A. cannabina, a more southern species. Records of the latter in the Ligurian Sea therefore need confirmation.
  6. Only a minority (22.6%) of A. polypoides records were in Marine Protected Areas, the remainder being located in areas with no current environmental protection plans in place. While the occurrence of this species in MPAs remained stable over the decades, the only quantitative historical data available indicated that populations in non-protected areas were declining owing to anthropogenic impacts (fishing and anchoring).
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8.
海山是海底重要的生物栖息地类型之一,是研究海洋生物多样性的热点区域。黄鳍金枪鱼 (Thunnus albacares) 广泛分布于中西太平洋,具有极高的生态和经济价值,然而,鲜有关于海山及其相关特征对黄鳍金枪鱼资源丰度和分布影响的研究。基于2010—2021年中西太平洋渔业委员会 (Western and Central Pacific Fisheries Commission, WCPFC) 汇总的延绳钓和围网渔业数据结合海山特征数据,采用广义加性模型 (Generalized additive model, GAM) 分析两种不同捕捞方式的黄鳍金枪鱼单位捕捞努力量渔获量 (Catch per unit effort, CPUE) 与海山相关特征之间的关系。结果表明,中西太平洋两种渔业方式的黄鳍金枪鱼渔获量主要来源于海山区域,海山特征对两种渔业黄鳍金枪鱼的CPUE均产生了极显著性影响 (P<0.001)。在延绳钓渔业中,较高的CPUE出现在山顶深度、粗糙度、底面积和海山密度较小、坡度较缓的区域;而在围网渔业中,较高的CPUE则出现在粗糙度较小、山顶深度较大、底面积较大、较陡峭且密集的海山区域。研究探讨了中西太平洋海山特征对黄鳍金枪鱼不同群体的影响机制,为今后进一步探索黄鳍金枪鱼种群分布和资源丰度变化与海洋环境的关系提供了参考与新思路。  相似文献   

9.

10.
虾类是海洋生态系统功能群的重要组成部分,其生物量变化受到多重因素的影响。本研究在开展黄海和东海北部水域虾类白斑综合征病毒(white spot syndrome virus, WSSV)流行病学调查的基础上,利用梯度随机森林模型(gradient random forest model, GFM)和广义加性混合模型(generalized additive mixed models, GAMM),分析了2016—2018年间黄海和东海北部水域WSSV流行对虾类生物量的影响。分子检测结果显示,调查所获取的26种虾类中,11种被检测为WSSV阳性;2016、2017和2018年WSSV阳性采样站点的比率分别为48.40%、38.75%和21.74%,虾类样品中WSSV阳性检出比率分别为16.86%、9.60%和4.80%。GFM模型分析显示,解释变量“阳性样品数的对数(ln_posi)”对响应变量“虾类生物量的对数(ln_Abu)”的重要性最高。GAMM分析中,根据赤池信息准则(Akaike information criterion, AIC)最小原则筛选出的最优模型为：ln_Abu~WSSV阳性率(P_rate)+ln_posi+经度(Long),该模型中ln_posi和P_rate是影响虾类生物量的极显著相关因子,ln_Abu随着P_rate的升高而降低。研究表明,WSSV在黄海和东海北部水域虾类中流行,推测对该海域的虾类生物量存在影响。  相似文献   

11.
    
  1. Seagrasses such as Zostera marina L. play a key role in coastal ecosystems because of the ecological goods and services that they provide, enhancing biodiversity, productivity and carbon sequestration. Despite their ecological relevance, their distribution is, to date, insufficiently documented and it is estimated that only one‐quarter of their global extent is mapped.
  2. This study aims to develop a new method to accurately detect and map subtidal seagrass meadows, using Irish seagrass populations as a case study. This method consists of four steps: (i) the development of a species distribution model (SDM); (ii) the use of satellite‐derived images to visually appraise the potential presence and extent of seagrass beds; (iii) field surveys to validate the presence or absence of the seagrass; and finally (iv) the construction of an up‐to‐date detailed map of the seagrass distribution for the region under investigation.
  3. Results indicate that along the Irish coast, and in western regions in particular, the actual distribution of seagrass is considerably greater than is currently reported. Using the proposed method, 16 new regions occupied by seagrass in areas of interest in County Galway (Kilkieran Bay, Bertraghboy Bay, and Chasla Bay) were identified, accounting for a total of 267.92 ha, which increased the previously documented distribution in this area by 44.74%.
  4. In this study, we demonstrate the potential of this novel method to efficiently identify and map undocumented subtidal seagrass meadows. As seagrass habitats are under threat globally, the development of new mapping strategies is a critical contribution to current international efforts in seagrass monitoring and management.
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12.
    
The effect of different dietary levels of docosahexaenoic acid (DHA, 22:6w-3) on the corresponding composition of lipid classes of the eyes of sea bass, Dicentraxrchus labrax, larvae was studied using Artemia nauplii enriched with different products: oil emulsions, liposomes, a dry microalga and baker's yeast. DHA was found to be a major constituent of phosphatidylserine and phosphatidylethanolamine of visual tissues. The different DHA dietary levels were markedly reflected in the fatty acid composition of the lipid classes of eyes, suggesting a dose-dependent relationship between DHA in the food and in visual tissue lipids of sea bass larvae. The possible implications of this dietary effect are discussed.  相似文献   

13.
繁茂膜海绵的实验室养殖   总被引：4，自引：0，他引：4  
为了实现可控条件下海绵(marine sponge)的快速生长,获得海绵生物量,解决海绵药物开发的“药源供给不足”的瓶颈问题,本研究以大连周边黄渤海潮间带的繁茂膜海绵(Hymeniacidon perleve)为研究对象,进行室内养殖实验,在自行设计的水体循环和不循环养殖体系水族槽内观察繁茂膜海绵的原代和继代生长过程。海绵经历贴壁、旺盛生长、出芽、静止生长和枯萎5个生长阶段。“窝”型巢穴有利于海绵生长和繁殖。实验过程中观察到繁茂膜海绵以一种拖丝迁移的方式分散新的个体以实现繁殖。扁藻和硅藻可以作为海绵的饵料。平缓的水流有利于海绵的生长。温度是影响海绵生长的关键因素,在一定温度刺激下,海绵会从过冬状态下苏醒,开始生长。  相似文献   

14.
    
  1. Recent research demonstrates a critical and ongoing need for capacity building of marine protected area (MPA) practitioners in order to ensure effective management of MPAs and MPA networks that protect coastal and marine ecosystems. MPA capacity development needs are site and network specific, although commonly include leadership development, building shared goals across networks, understanding impacts and identifying appropriate management approaches, and building system‐wide monitoring and evaluation programmes.
  2. Designing capacity‐building programmes at the network scale can contribute directly to enhancing learning and social networking, sustaining and strengthening effective management of ecosystems, and improving coordinated network governance. Network‐wide capacity building amplifies the effect and availability of technical resources and expertise, lessons learned at different management scales, and collaborative decision‐making. The net result is shared capacity development across the network and improved functioning of multiple MPAs as a unit, all from a singular capacity‐building effort.
  3. In the spirit of contributing to the ongoing growth of the global social network of MPA practitioners, this paper shares observations from social MPA network building as part of recent MPA capacity building in the Philippines and Indonesia. These programmes deliver technical capacity and a participatory learning framework for participants to enhance their MPA social network and support long‐term implementation of gained knowledge and skills.
  4. Important elements in supporting successful network development through capacity‐building programming include:
    • comprehensive needs assessment;
    • strong collaborative partnerships for programme delivery;
    • clear learning objectives and intended long‐term results; and
    • strong and sustained political will at the local, national, and regional scales.
  5. Each MPA site, region, and capacity‐building programme is unique in structure and content, yet what all programmes have in common is that they build on the principles of trust and community building to create a locally relevant format and framework for the network to flourish.
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15.
    
  1. Oceanic marine protected areas (MPAs) that are close to the litter accumulation zones in the subtropical gyres receive large amounts of plastic litter, both as micro‐ and as macroplastics.
  2. The macro‐litter accumulating on the islands in the Easter Island Ecoregion (Rapa Nui and Salas y Gómez) can be traced back to the high seas industrial fishery operating in the South Pacific.
  3. Seabirds nesting in the MPAs in the South Pacific are affected by both microplastic ingestion and macroplastic in their nests, but there was no evidence of entangled birds.
  4. Conservation of seabirds (and other species) in these oceanic MPAs requires efficient measures to reduce plastic contamination in the ocean.
  5. Observations made in the South Pacific coincide with those from other oceanic MPAs, calling for global actions.
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16.

17.
Visual and chemical cues stimulate microdiet ingestion in sea bream larvae   总被引：1，自引：1，他引：1  
The aim of the present study was to investigate the mechanisms by which the presence of Artemia nauplii in the rearing medium stimulates the feeding behaviour of gilthead sea bream, Sparus auratus. Sea bream larvae were given a microdiet ad libitum in the complete absence or the presence of chemical or visual stimuli of Artemia nauplii in the following way. The larvae were offered a microdiet in containers in which they had only visual contact with the nauplii. Alternatively, larvae were given the microdiet in the presence of only the Artemia-rearing culture-medium, which served as a chemical stimulus. Finally, larvae were exposed to both stimuli: visual and chemical. The stimuli were given at different levels which were equivalent to Artemia concentrations ranging from 3 to 12 nauplii ml-1. The present study demonstrated that while 20-day old larvae fed at a rate of 2.78 mg larva-1 h-1 in the absence of Artemia stimuli, their feeding rate increased by 120%, to 6.3 mg larva-1 h-1 in the presence of both chemical and visual stimuli. The stimuli work synergistically with each other, where the additive effect of each of the stimuli given alone was smaller than the two stimuli given together. Artemia's chemical stimulation amounted to a 35% improvement in larval microdiet feeding rate as compared with the control. This stimulus could be attributed mainly to the presence of four metabolites that were found in abundance in the Artemia-rearing medium: betaine and the free amino acids, arginine, alanine and glycine. In conclusion, the results suggest that the feeding response of marine larvae on microdiets could be elicited by the presence of visual and chemical stimuli. The latter could be added to the larvae-rearing medium separately or possibly could be made to leach out of the microdiets as they are fed to the larvae.  相似文献   

18.
本研究于2018年9—11月在山东省青岛市薛家岛海域构建了包含鱼类网箱、马氏珠母贝(Pinctada martensi)和异枝麒麟菜(Eucheuma striatum)的多营养层次综合养殖(IMTA)模式,开展现场实验的同时,在室内测定了马氏珠母贝的摄食生理指标和异枝麒麟菜的营养盐吸收速率,对比分析了贝藻综合养殖对网箱养殖区的水质改善效果。结果显示,实验点马氏珠母贝壳高及特定生长率(SGR)均显著高于对照点,水层为0.50~0.62 m的马氏珠母贝平均壳高显著高于其他水层。实验点异枝麒麟菜的净增重显著高于对照点,水深为0.60~0.90 m的生长速率最高;在24.45℃条件下,马氏珠母贝对颗粒有机物(POM)的摄食率、吸收率和吸收效率均值分别为(4.13±0.77) mg/(h·ind.)、(1.04±0.24) mg/(h·ind.)和(25.00±2.51)%,均显著高于20.74℃实验组;在实验温度范围内,异枝麒麟菜对N、P、Si营养盐的吸收速率均随着温度升高呈先升高再降低的趋势,最高值出现在30℃。实验期间,马氏珠母贝摄食和吸收的POM分别为778.08和144.47 g,异枝麒麟菜吸收的N、P、Si总量分别为8.55、1.11和9.18 g,均高于对照点。研究表明,温度、养殖深度、POM及营养盐浓度是影响马氏珠母贝和异枝麒麟菜生长及生理代谢的主要因素。  相似文献   

19.
    
Fishing sustainably is a fundamental problem in tropical regions where diverse fisheries and scarce fisheries information challenges efforts to make reliable estimates and associated policies. To improve evaluations and decisions, we compared the predictions of six surplus production models calibrated using various permutations of fisheries‐dependent data with a benchmark model. The benchmark model was built from fisheries‐independent estimates of r and K, tested against rates of change in Kenyan reef fisheries and found to be accurate. Comparisons with the benchmark model were made with fisheries‐dependent equilibrium and non‐equilibrium models, fixing or not fixing r and K, pooled versus site averaged solutions, and rising, falling, and pooled fishing effort over time. Evaluations indicate high variability in MMSY predictions and notable overestimates of MMSY (~75%) and effort (~210%) for Fox and Schaefer equilibrium models. Non‐equilibrium models had high failure rates (~25%) but successful fits performed better and indicated smaller overestimates (16%) for site‐level evaluations. The Pella–Tomlinson model was most accurate (MMSY = 5.6 ± 0.60 (SD) tonnes/km2/year) and best‐fit r‐K relationships also aligned well with ecoregional data on K and short‐term yields. Future efforts are advised to pool site data, use conservative recruitment values (z = 0.8), and collect data across times of both rising and falling effort. Recommended methods and subsequent adjustments of the benchmark model should improve local and ecoregional scale MMSYs. The benchmark model was calibrated to estimate MMSY in fished seascapes, but to conserve species with slower life histories, we suggest modifications to limit MMSYs to between 1.8 and 3.2 tonnes/km2/year.  相似文献   

20.
南沙群岛西南部海域和北部湾口海域底层游泳动物多样性   总被引：2，自引：0，他引：2  
根据2012—2013年在南沙群岛西南部和北部湾口海域进行的秋季和春季两个航次的调查资料,分析了这两个区域游泳动物的种类组成,计算渔获种类的相对重要性指数(IRI)、Margalef种类丰富度指数(D)、Shannon-Weiner种类多样性指数(H′)、Pielou均匀度指数(J′)和资源密度。结果表明,南海调查海域春秋两个航次的渔获物中,共鉴定出游泳动物663种,隶属于4纲36目171科374属;其中鱼类为504种,占所有渔获种类的76.0%。优势种种数较少,且季节变化较大。春季游泳动物的多样性指数高于秋季,这主要是由于春季出现大量补充群体,并且有许多种类在秋季向较深海区移动所造成的。南沙群岛西南部海域游泳动物多样性指数高于北部湾口海域,这可能是由于南沙群岛西南部海域受水温和洋流的影响较大所造成的。目前,南海北部渔业资源处于过度捕捞状态,资源结构呈现小型化和低值化。对南北海域资源调查结果进行比较发现,南沙群岛西南部海域资源相对较好。应合理开发利用该海域渔业资源,同时加强物种多样性的保护工作。  相似文献   

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