Coral Recruitment and Regeneration on a Maldivian Reef 21 Months after the Coral Bleaching Event of 1998     

Karen Loch  Wolfgang Loch  Helmut Schuhmacher  Wolf R. See 《Marine Ecology》2002,23(3):219-236

Abstract. This paper describes the quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998. The detailed data, collected in March 1999 and March 2000, comprise survival, new recruitment and regenerates. They were obtained in 6 transects laid out randomly on the reef flat, on 22 Acropora tables on 6 sites at the reef edge and on 39 Porites lobata blocks and 1 Diploastrea heliopora colony. The present cover of living zooxanthellate corals is reduced to ca. 2 – 5 % of its previous state. Acroporidae and Pocilloporidae were practically wiped out, while Poritidae survived partly and Agariciidae (esp. Pavona) are now the dominant group. New settlements on dead Acropora tables were mainly Agariciidae, followed by Acroporidae and Pocilloporidae. Regenerates on Porites were pronounced and the apparent yearly increase in mass was about threefold that of Diploastrea, which is 3 – 4 mm per year. The influence on reef ecology in terms of coral substrate and species, possible sources of larvae, change of guilds in reef builders, other species and the prospect for further development of the reef, with respect to growth versus erosion, is discussed.  相似文献   

Sublittoral seaweed communities on natural and artificial substrata in a high-latitude coral community in South Africa     

L Gersun  JR Hart  GW Maneveldt  JJ Bolton 《African Journal of Marine Science》2016,38(3):303-316

Coral mortality may result in macroalgal proliferation or a phase shift into an alga-dominated state. Subtidal, high-latitude western Indian Ocean coral communities at Sodwana Bay on the KwaZulu-Natal coast, South Africa, have experienced some mortality because of warm-water anomalies, storms and other causes, but the response of the macroalgae is unknown. We investigated the abundance and diversity of benthic algae on different hard natural substrata (dead digitate, brain and plate corals and beach rock) on Two-Mile Reef, Sodwana Bay. We also compared algal communities colonising ceramic, marble and pretreated ceramic tiles placed on the reef for six months. We identified 95 algae (14 Chlorophyta, 11 Phaeophyceae, 69 Rhodophyta and one cyanobacterium). Assemblages on natural and artificial substrata were dominated by the brown alga Lobophora variegata (Lamouroux) Womersley ex Oliveira and non-geniculate corallines (Rhodophyta, Corallinaceae). Cluster and ordination analyses revealed that the algae showed no affinity for particular substrata, whether natural or artificial. Algal cover was occasionally higher on rougher tiles and crustose corallines were significantly more abundant on marble than ceramic tiles. Two-Mile Reef had 23.1% dead and 48.4% live scleractinian coral cover, where dead corals were colonised indiscriminately by many small algal species, but there was no evidence of algal proliferation. The results provide a baseline for monitoring this high-latitude reef system.  相似文献   

A study of coral reef resilience and implications of adaptive management and rehabilitation in Khanh Hoa Province, Vietnam     

VO Si Tuan  HUA Thai Tuyen  PHAN Kim Hoang 《海洋学报(英文版)》2019,38(1):112-117

The Province of Khanh Hoa, Vietnam, is located in the western South China Sea and boasts a shoreline of 385 km and many islands. Previous studies have indicated the extreme diversity and abundance of coral reefs in its waters as compared with other coastal provinces of Vietnam. A study on the resilience of coral reefs against increased surface water temperature and anthropogenic impact is conducted at 19 reef sites in 2015. At each site, a series of parameters (e.g., coral covers, genus diversity, and coral recruitment, substratum heterogeneity, depth, water exchange level, and sediment deposit and water temperature) are measured quantitatively or semi-quantitatively. The measured data are rated based on the relationship between the parameter values and coral susceptibility; the consideration that reef health reflects the biological capability to adapt to environmental changes and the recruitment potential if bleached; and positive or negative influences of physical factors in the mitigation of thermal stress and protecting corals from bleaching. A cumulative analysis enables researchers to divide the studied reefs into four categories based on varying levels of reef health to support resilience, recovery, and vulnerability in the case of increased water temperature. Relevant management interventions for each category and other supporting activities are suggested to enhance management effectiveness and to plan the rehabilitation of coral reefs for biodiversity conservation and touristic development, taking into account the involvement of related stakeholders.  相似文献   

Low reproductive success for copepods during a bloom of the non‐aldehyde‐producing diatom Cerataulina pelagica in the North Adriatic Sea     

Adrianna Ianora  Raffaella Casotti  Mauro Bastianini  Christophe Brunet  Giuliana D’Ippolito  Francesco Acri  Angelo Fontana  Adele Cutignano  Jefferson T. Turner  Antonio Miralto 《Marine Ecology》2008,29(3):399-410

Egg production rates and/or hatching success in the copepods Acartia clausi, Calanus helgolandicus and Temora longicornis were negatively affected by a late spring (May–June 2003) phytoplankton bloom in the North Adriatic Sea, dominated mainly by the large diatom Cerataulina pelagica. Highest total concentrations of 3.3·10⁴ cells·ml^?1 were located in the vicinity of the Po River, which also corresponded to the area where the highest numbers of phaeophorbides were measured (0.779, 0.528 and 0.419 μg·l^?1, respectively, compared to an average of the remaining stations of 0.183 ± 0.049 SD), suggesting some grazing on the bloom. Phytoplankton biomass in terms of carbon was dominated by diatoms, representing on average 42% of total phytoplankton carbon and more than 80% at several stations. Cerataulina pelagica, Cyclotella spp., Chaetoceros spp. and small unidentified centric diatoms dominated the diatom community numerically but C. pelagica was by far the dominant diatom in terms of carbon due to its large cell size. This species represented more than 60% of the diatom biomass at nine of the 14 stations sampled, and was absent only at one station, which was the most offshore station sampled during the cruise. Although polyunsaturated aldehydes (PUAs) were not detected, other oxylipins which are hydroxy and keto derivatives of eicosapentaenoic and docosahexaenoic acids that affect copepod reproduction were found in these samples. Hence, we can attribute the negative impact of diatoms not only to PUAs, as previously believed, but also to these compounds. This is the first direct evidence of the presence of oxylipins other than PUAs in marine blooms dominated by diatoms.  相似文献   

Welcome mats? The role of seagrass meadow structure in controlling post-settlement survival in a keystone sea-urchin species     

Patricia Prado  Javier Romero  Teresa Alcoverro 《Estuarine, Coastal and Shelf Science》2009

Processes acting on the early-life histories of marine organisms can have important consequences for the structuring of benthic communities. In particular, the degree of coupling between larval supply and adult abundances can wield considerable influence on the strength of trophic interactions in the ecosystem. These processes have been relatively well described in rocky systems and soft-sediment communities, and it is clear that they are governed by very different bottlenecks. Seagrass meadows make interesting study systems because they bear structural affinities to both soft sediments as well as rocky substrates. We examined the early-life history of Paracentrotus lividus, one of the dominant herbivores in Mediterranean seagrass meadows, to identify the drivers of population dynamics in this species. We measured spatial and temporal variability in sea urchin post-settlement in 10 Posidonia oceanica meadows in the North-Western Mediterranean over a period of two years, and compared the numbers with the one-year old cohort a year later (i.e. the new population recruitment) as well as between successive size–age groups. Urchin post-settlers differed substantially between meadows but were present in both years in all meadows surveyed, suggesting that larval supply was not limiting for any of the studied sites. However, in six of the studied meadows, the one-year cohort of urchins was absent in both years, indicating that post-settlement processes strongly affected urchins in these meadows. In contrast, in four of the studied meadows, there was a strong coupling between post-settlers and one-year cohort individuals. These meadows were structurally different from the others in that they were characterised by an exposed matrix of rhizomes forming a dense seagrass mat. This mat apparently strongly mediates post-settlement mortality, and its presence or absence dictates the successful establishment of urchin populations in seagrass meadows. As the population aged, the relationship between size–age groups decreased evidencing the action of other processes. Yet, these results indicate that differences in physical structure are a vital bottleneck for sea urchin populations in seagrass meadows. Exploring the interaction between ecosystem structure and early-life history may provide a broader and more unified framework to understand the dynamics of a range of benthic habitats, including rocky substrates, soft sediments and seagrass meadows.  相似文献   

Climatic regimes and the recruitment rate of anchoveta, Engraulis ringens, off Peru   总被引：2，自引：0，他引：2  

Sandra M. Cahuin  Luis A. Cubillos  Miguel iquen  Rubn Escribano 《Estuarine, Coastal and Shelf Science》2009,84(4):591-597

The recruitment rate of Peruvian anchoveta, Engraulis ringens, was studied to test the hypothesis that long-term environmental variation (regime shifts) had a significant impact on density-dependent processes governing the anchovy recruitment during the period 1963–2004. On the basis of previous defined regimes and turning points for the Humboldt Current System, we identified two groups of years for increased recruitment of anchoveta (1963–1971 and 1986–2004), and one unfavorable period (1972–1985). A common intercept and significantly different slopes were found when the recruitment rate was plotted as a function of the spawning stock biomass during those groups of years, suggesting that density-dependent effects on recruitment were affected during different climate regimes. The favorable (unfavorable) regime was characterized by higher (lower) zooplankton volumes, and with a higher frequency of colder (warmer) waters. Dome-shaped relationships between recruitment rate, spawning stock biomass and SST, were detected with a Generalized Additive Model for the favorable regime. Thus, recruitment could be explained by non-linear effects of environmental variables. Ultimately, climatic regimes are affecting the density-dependent effects on recruitment of anchoveta and the mechanisms involved may be associated with changes in the carrying capacity of the spawning habitat of anchoveta off Peru, which in turn are related with the effects of cold and warm regimes.  相似文献   

Fish trapping experiments in Northern New Zealand waters     

James Crossland 《新西兰海洋与淡水研究杂志》2013,47(3):511-516

Fish trapping experiments were carried out during 1973–75 along the north‐east coast of the North Island. The most effective trap type was the Z‐trap. Two sizes of Z‐trap were tested. Better results were obtained with the larger ones, which had an overall mean catch rate of 8.4 fish/trap day. The catch rate varied widely between areas, bottom types, and seasons. Best results were obtained in summer in depths greater than 20 m.  相似文献   

Can dynamite-blasted reefs recover? A novel, low-tech approach to stimulating natural recovery in fish and coral populations     

Raymundo LJ  Maypa AP  Gomez ED  Cadiz P 《Marine pollution bulletin》2007,54(7):1009-1019

Throughout Southeast Asia, blast fishing creates persistent rubble fields with low coral cover and depauperate fish communities. We stabilized a 20-year-old rubble field in a Marine Protected Area in the Philippines, using plastic mesh and rock piles in replicated 17.5m(2) plots, thereby increasing topographic complexity, fish habitat, and recruitment substrate surface area. Multivariate analysis revealed fish community shifts within the rehabilitated area from that characteristic of rubble fields to one similar to the adjacent healthy reef within three years, as measured by changes in fish abundance and body size. Coral recruitment and percent cover increased over time, with 63.5% recruit survivorship within plots, compared with 6% on rubble. Our low-cost approach created a stable substrate favoring natural recovery processes. Both rehabilitation and the elimination of poaching were integral to success, emphasizing the synergism between the two and the need to incorporate both when considering mitigation.  相似文献   

海南铜鼓岭国家级自然保护区海域珊瑚的分布及其健康状况评价   总被引：1，自引：0，他引：1  

李元超  陈海洲  郑新庆  王道儒 《台湾海峡》2014,(4):539-545

沿铜鼓岭国家级自然保护区海岸南北两侧沿岸布设8个站位,采用断面监测法调查了珊瑚的种类多样性、覆盖率、死亡率和补充量等指标,并利用健康指数（CI）评估了铜鼓岭珊瑚礁生态系统的健康状况和遭受环境压力的程度.本次调查共发现铜鼓岭造礁石珊瑚11科23属40种,软珊瑚8种,造礁石珊瑚和软珊瑚覆盖率分别为13.8%和19.4%,该海域珊瑚礁生态系统保存较为完好和健康.铜鼓岭珊瑚的覆盖率呈现明显的空间分布特征,北侧珊瑚覆盖率为0.1%～9.8%之间,远低于南侧的水平（8.1%～66.1%）.从珊瑚补充量来看,铜鼓岭北侧珊瑚的恢复能力基本为零,而铜鼓岭以南的区域可以有0.4个/m^2珊瑚新个体.通过比较2006年以来珊瑚种类、覆盖率、死亡率、补充量、健康指数等方面的调查数据,认为铜鼓岭保护区的珊瑚礁生态系统得到有效保护,珊瑚礁生态系统处于健康状态.  相似文献   

Otolith Microstructure Analysis Reveals Different Growth Histories of Japanese Sardine (Sardinops melanostictus) in the Oyashio Waters     

LIU Chunlin  ZHANG Chi  TIAN Yongjun  WANG Liangming  LIN Longshan  LI Yuan  WATANABE Yoshiro 《中国海洋大学学报(英文版)》2022,21(1):236-242

After decades of low year classes,the stock of Japanese sardine(Sardinops melanostictus)has begun to recover since the mid-2000s.The hatch dates and otolith growth rates of age-0 juvenile sardine,which were collected in the subarctic Oyashio waters in autumn 2018,were determined from an otolith microstructure analysis.The sardines were hatched from late January to late April,while mostly in February and March.The otolith growth rate increased continuously up to 60 d after hatching and thereafter de-creased.The revealed growth rate in a crucial growth period is faster than that reported for juvenile sardines collected in the 1990s,which is coincided with the recent recovery trend of the sardine stock.Two groups with different hatch dates,growth histories,and migration routes were identified using unsupervised random forest clustering analysis.They were considered inshore and offshore migration individuals in accordance with recent researches.In the offshore group,a high proportion of sardine juveniles hatched late and grew faster in the Kuroshio-Oyashio transitional waters,a finding consistent with the hypothesis of growth-rate-dependent re-cruitment.This finding on the population composition and growth rate of juvenile sardine in the Oyashio waters can be a basis for an improved prediction of their survival and provides us with valuable information on the recruitment processes of this stock during the period of stock recovery.  相似文献