共查询到20条相似文献，搜索用时 46 毫秒
1.
Yuichi Preslie Kikuzawa Tai Chong Toh Chin Soon Lionel Ng Shu Qin Sam Daisuke Taira Lutfi Afiq‐Rosli Loke Ming Chou 《Aquaculture Research》2018,49(6):2249-2255
In coral mariculture, growth is one of the most common ways to track success. However, numerous methods of monitoring coral growth make comparative studies challenging. A literature review of 39 studies from 1982 to 2017 indicated that the most predominant non‐invasive methods used were linear and areal measurement and these were evaluated for their accuracy using nursery‐reared corals. The monthly change in linear and areal growth rates of six coral species (n = 215), Pocillopora acuta, Hydnophora rigida, Merulina ampliata, Podabacia crustacea, Echinopora lamellosa and Platygyra sinensis were measured via photogrammetry. We tested whether the planar area of coral colonies can be estimated using three geometric formulas of linear measurements. Based on the literature review, the six types of measurement methods were namely linear, volume, weight, area, count of polyps/branches and calcification, in decreasing order of application. Our results showed that the change in area calculated by geometric mean diameter (GMD) formulas provided the most accurate estimation among the three formulas and was strongly correlated with planar area (R2 ≥ .60; p < .05) for all coral species, except E. lamellosa and Pl. sinensis. However, our findings suggest that it is not ideal to use geometric formulas to estimate the change in area. Instead, we posit that areal photogrammetry represents the simplest yet accurate non‐invasive method for rapid monitoring of extensive areas of corals in situ. Lastly, we discuss the recommendations and limitations for areal photogrammetry. 相似文献
2.
- 1. Coral reefs around the world have been deteriorating over decades owing to anthropogenic pressure. In the Caribbean recent rates of decline are alarming, particularly for coral reefs under high local human impact, many of which are severely degraded, although regions with lower direct anthropogenic influence seem less affected.
- 2. Little Cayman is a relatively undeveloped island, with less than 150 permanent residents. About 20% of its reefs have been protected by no‐take marine reserves since the mid‐1980s. We analysed the dynamics of coral communities around the island from 1999 to 2004 in order to test the hypothesis that a lack of major local anthropogenic disturbances is enough to prevent decline of coral populations.
- 3. Live hard coral coverage, coral diversity, abundance, mortality, size, and prevalence of disease and bleaching were measured using the Atlantic and Gulf Rapid Reef Assessment methodology (line transects) at nine sites. Despite the apparent undisturbed condition of the island, a 40% relative reduction of mean live coral coverage (from 26% to 16%, absolute change was 10%) was recorded in five years. Mean mortality varied from year to year from 23% to 27%. Overall mean diameter and height have decreased between 6% and 15% on average (from 47 to 40 cm for diameter, and from 31 to 29 cm for height).
- 4. The relative abundance of large reef builders of the genus Montastraea decreased, while that of smaller corals of the genera Agaricia and Porites increased. Disease prevalence has increased over time, and at least one relatively large bleaching event (affecting 10% of the corals) took place in 2003.
- 5. Mean live coral cover decline was similar inside (from 29% to 19%) and outside (from 24% to 14%) marine no‐take reserves. No significant difference in disease prevalence or clear pattern in bleaching frequency was observed between protected and non‐protected areas. It is concluded that more comprehensive management strategies are needed in order to effectively protect coral communities from degradation.
3.
Mineo Okamoto Satoshi Nojima Syuichi Fujiwara Yasuo Furushima 《Fisheries Science》2008,74(6):1245-1253
A ceramic coral settlement device (CSD) was developed to raise juvenile corals in situ in preparation for transplantation. The CSD is designed to be deployed in the water before mass spawning of corals, allowing
larvae to settle and grow on the CSD before it is fixed to the reef structure. CSDs were aggregated and fixed on 0.2-m2 frames (either 648 or 720 CSDs per frame) and deployed in the Sekisei Lagoon around the full moons of April and May in 2002.
Seven frames were collected in August 2002 and settled corals were counted in the laboratory. The maximum number of coral
colonies settled on CSDs in one frame was 617, with 94% belonging to the genus Acropora. The aggregated CSDs successfully functioned as a coral settlement substratum, with more appropriate arrangement of CSDs
on the frame, enabling greater exposure to sunlight and currents, which is expected to increase the amount of settlement. 相似文献
4.
To evaluate the effect of inexpensive cages made from concrete and bamboo on the skeletal extension rates of the scleractinian corals Acropora gomezi and Pavona cactus, fragments were cultured without cages, inside partial cages, and inside full cages with bamboo covers of two mesh sizes at different depths around Sambangan Island, Indonesia. An additional experiment was designed to assess the impact of shading by cages on skeletal extension. Linear extension rates of all fragments were measured over a period of four months. Culture inside cages led to significantly reduced extension rates of A. gomezi at both depths, while P. cactus only showed significantly reduced extension rates when cultured in full cages at greater depth. Caging lead to a significant increase in skeletal damage at both depths in A. gomezi, and at shallow depth in P. cactus. Shaded fragments of A. gomezi had much smaller extension rates (5 ± 1 mm/132 days, mean ± SE) than unshaded fragments (24 ± 1 mm/132 days) and sustained significantly more damage, while shaded fragments of P. cactus grew significantly better (15 ± 0 mm/132 days) than unshaded fragments (12 ± 0 mm/132 days) and sustained less damage, although the difference was not significant. The culture of coral fragments without cages may yield the best results. However, the choice of the optimal culture method will depend on the species to be cultured and the conditions encountered in the reef. 相似文献
5.
6.
Richard Thomas B. Pavia Janet S. Estacion 《Journal of the World Aquaculture Society》2019,50(1):219-230
Coral aquaculture is viewed as a sustainable method of providing colonies for use in the aquarium trade, pharmacological studies, and coral reef rehabilitation. The production of large, healthy specimens depends on providing conditions that mimic or surpass natural reef environments. Materials with a high degree of variability in physical and chemical properties are utilized as substrates in coral aquaculture, but until fragment–substrate interactions are isolated and independently studied, the possible inhibitory and facilitative effects of each material will remain unclear. To understand potential key roles that substrates can play in coral culture, a comparison was made about the role of various materials on fragment survival and growth. The experiment examined the interactions between isolates of a common scleractinian coral, Galaxea fascicularis, and six commonly used substrates (coral rock, terracotta, polyvinyl chloride, steel, rubber tire, and concrete) and how these affected survival and growth. No differences were observed in the survival, colony size, and polyp production of the resulting microcolonies. The results show that, for G. fascicularis, growth is not affected by substrate type. The results demonstrate the use of a wide variety of materials for the successful aquaculture of scleractinian corals. 相似文献
7.
K. Ley‐Cooper S. De Lestang B. F. Phillips E. Lozano‐Álvarez 《Fisheries Management and Ecology》2014,21(4):264-274
The Caribbean spiny lobster, Panulirus argus, Latreille, is the main source of income for the communities in the Sian Ka'an Biosphere Reserve Mexico. The fishery has recently been certified as sustainable by the Marine Stewardship Council provided that further stock assessment is carried out. A total of 379 lobsters were tagged in an unfished area offshore from the Bahía del Espíritu Santo fishing grounds to assess whether lobsters remained within these areas and were thus fully protected. The lobsters recaptured in the shallow area (5.3%) were sufficient to develop a multistate mark recapture model, which takes into account fishing and natural mortality, tag reporting rate and tag loss. This estimated that between 15 and 20% of all adult lobsters dwelling in the unfished area moved into the fishery and were subjected to exploitation. This study suggests that the offshore unfished area provides protection to the majority of the stock in this area while adding to and maintaining fishing yields within the inshore commercial fishery. 相似文献
8.
9.
10.
11.
三亚湾近10年pH的时空变化特征及对珊瑚礁石影响分析 总被引：1，自引：0，他引：1
文章对三亚湾近10年的海水酸碱度（pH）数据分析发现,三亚湾的pH变化范围表层为8,01—8．23,底层为8．01～8．24,平均为8．14。2001年后三亚湾水体pH呈现明显的下降趋势,从年平均的8．30以上下降到8．07,下降了0．2,大于全球平均海水酸化速度。从pH垂直分布来看,出现4种类型：1）上层pH小,下层pH大;2）上层和下层pH大,中层pH小;3）上层和下层pH小,中层pH大;4）上层、中层和下层pH出现明显的递减趋势。从pH的平面分布来看,不同季节pH的分布有一定的变化,但在河口区域,pH相对较小的趋势出现概率较大。珊瑚礁石溶钙试验表明,pH由7增加至8时,溶钙量约由12mg·L^-1呈指数下降至约1mg·L^-1,下降约91．67％。目前三亚湾pH仍然处于珊瑚礁正常生长的范围之内（8．0—8．3）,pH在一定程度的降低还未对珊瑚生长产生较大的负面影响。 相似文献
12.
13.
Fish landing data from the Mombasa Marine National Park (MNP) and a marine reserve exploited by various gears were studied over a 5‐yr period to determine the influence of the closed area and different gears in fisheries. The number fishing and boats per landing site was constant, but total and catch per unit effort progressively declined in all sites on an annual basis irrespective of the existence of a marine reserve, exclusion of the beach seines or use of gear. Differences between landing sites were most pronounced when analysed on a catch per area as opposed to the more standard catch per fisherman, suggesting compensation in human effort when catches decline. A marine reserve next to a closed area that excluded beach seines had the highest catch per area (5.5 kg ha?1 month?1) despite having the highest density of fishermen (0.07 ± 0.02 fishermen ha?1 month?1). The annual rate of decline in the catch was lower than the other sites at around 250 g day?1 compared with 310–400 g day?1 in the other sites. One landing site, which excluded beach seine landings for more than 20 yrs, had a high catch per area (～5.3 kg ha?1 month?1), but after experiencing a doubling in the effort of other gears (line, speargun and trap), the catch per fisherman and area were reduced. Environmental or habitat degradation and excessive effort remain the most likely explanation for the overall declines in catch from 1995 to 1999. Closed areas and beach seine exclusion have the potential to increase catch rates, but the first often reduces the total fishing area and possibly leads to a loss of total catch, at least on a time scale of less than 10 yrs. The exclusion of beach seines can lead to an increase in other gear types that can also cause reductions in catch. 相似文献
14.
Matthew S. Kendall John D. Christensen Christopher Caldow Michael Coyne Christopher Jeffrey Mark E. Monaco Wendy Morrison Zandy Hillis‐Starr 《水产资源保护:海洋与淡水生态系统》2004,14(2):113-132
- 1. A necessary component of implementing a successful marine reserve is the quantification of the biological resources that fall under its protection. Without such an initial assessment, the future effects of the reserve on the local habitat and biotic community cannot be quantified and will remain the subject of debate.
- 2. This study provides such a baseline assessment of fish diversity and habitat types within a recently enlarged marine reserve. Buck Island Reef National Monument, US Virgin Islands, was recently enlarged from approximately 4 km2 to over 76 km2. Areas of sand, seagrass, and hard‐bottom under protection were increased from 0.29 km2, 0.47 km2, and 1.96 km2 to 2.70 km2, 2.89 km2, and 18.30 km2 respectively when the Monument was expanded. A 53 km2 area of pelagic/deep‐water habitat with unknown bottom type is now also protected by the Monument.
- 3. Visual counts of fish within 25×4 m2 transects conducted during the day were used to assess fish community structure and habitat utilization patterns. Species richness, diversity, assemblage structure, and fish density were evaluated and compared among sand, seagrass, and hard‐bottom habitats. Hard‐bottom sites had over twice the mean species richness and diversity as sand and seagrass sites, and several times greater mean fish density.
- 4. Quantification of the fish community in pelagic and deep‐water habitats within the reserve is recommended to provide a more comprehensive assessment of the offshore areas of the reserve. Fish numbers, size, and diversity outside the reserve boundaries must also be evaluated to allow quantification of the effects of the marine reserve on the adjacent fish communities.
15.
16.
Comparison of invertebrate abundance in a seagrass bed and adjacent coral and sand areas at Amitori Bay,Iriomote Island,Japan 总被引：1，自引：0，他引：1
ABSTRACT: To examine whether or not reef-associated seagrass beds harbor abundant food resources for resident and visiting fishes, the invertebrate density and biomass in a seagrass bed were compared with those in adjacent coral and sand areas at Amitori Bay, Iriomote Island, Japan, in June 2002. The vegetation within the bed was dominated by Enhalus acoroides , the coral area comprising primarily Acropora spp. Epifaunal density was greater on the seagrass than on the corals, whereas biomass was greater on the latter. Tanaids, chironomid larvae, errant polychaetes, and gammaridean amphipods were dominant taxa on the seagrass; larger crustaceans, such as crabs and shrimps, being abundant on the corals. The density of infauna was greatest in the seagrass bed, followed by the coral and sand areas, whereas biomass was greatest in the coral area, followed by the seagrass bed and sand area. Each of the three habitats was dominated by harpacticoid copepods and errant polychaetes, although the density of each taxonomic group differed among the habitats. Important food items of seagrass bed fishes, such as harpacticoid copepods, gammaridean amphipods, errant polychaetes, and tanaids, were abundant in the seagrass bed, the density of each being greater than in the other two habitats. 相似文献
17.
ABSTRACT: Hermatypic (reef-building) corals harbor dinoflagellate endo-symbionts Symbiodinium spp. In studying gene expression in such symbiotic corals, problems arise regarding how to distinguish the coral and symbiont mRNA, and how to estimate their fractions in the mRNA population of the holobiont (symbiotic complex of the coral and Symbiodinium cells). In this study, these issues were addressed using juveniles of hermatypic coral Acropora tenuis in symbiosis with Symbiodinium cells of strain PL-TS-1. First, the guanine-cytosine (GC) contents were determined in expressed sequence tags (EST) from PL-TS-1 cells cultured in vitro and symbiont-free larvae of A. tenuis , and their average GC contents were found to be significantly different. The average GC content of the EST from the holobiont was much closer to that of A. tenuis larvae, suggesting that the majority (>90%) of mRNA isolated from the holobiont originated in the host. In protein-coding sequences, little overlap was observed between the GC-content distributions of PL-TS-1 cells and A. tenuis larvae. All of the coding sequences ( n = 59) found in the A. tenuis EST had GC contents below 0.5, whereas the GC content exceeded 0.5 in the majority (43/44) of coding sequences from the nuclear genome of PL-TS-1 cells. 相似文献
18.
- 1. This paper reports on the dynamics of the coral community structure at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, focusing on data collected before and after the summer typhoon seasons in 1997 to 1999. This period (1999) experienced the highest frequency of severe tropical cyclones to hit Hong Kong with one cyclone being the strongest to hit in the last 23 years (1984 to 2006).
- 2. This is part of a long‐term monitoring programme of subtropical coral communities that has been set up in AMW since May 1997 and AYW since May 1998 with nine fixed position 40 m long transects and 0.5 m × 0.5 m permanent quadrats laid at 5 m intervals along each transect. A total of 45 scleractinian coral species from 21 genera (12 families) was recorded, with 40 species in AMW and 32 species in AYW recorded at the beginning of the study.
- 3. Multidimensional scaling ordinations showed distinct spatial variations in the coral communities within and between sites. These variations were probably a result of the differential effects of the repeated cyclone impacts on the communities. Cyphastrea serailia, Goniopora lobata, Montipora peltiformis and Pavona decussata were the dominant species most strongly affected by cyclone impacts at AMW, experiencing a 6.2–16.2% loss of mean area cover during the study period. Some dominant species (e.g. P. decussata) in AYW also experienced a 6.5–14.3% loss of mean area cover within the same period.
- 4. Overall, these coral community structures appeared relatively stable and resistant to repeated physical disturbances. However, they may have low resilience towards more severe disturbances in the future. Preserving the resilience of coral communities/species in Tung Ping Chau should be one of the main goals of coral conservation strategies for the island.
19.
Nomie Jublier Frdric Bertucci Loïc Kver Orphal Colleye Laurent Ballesta Richard S. Nemeth David Lecchini Kevin L. Rhodes Eric Parmentier 《水产资源保护:海洋与淡水生态系统》2020,30(1):42-52
- Passive acoustic monitoring (PAM) is a non‐invasive technique that uses hydrophones to monitor populations and ecosystem dynamics. Although many applications of PAM have been developed in recent years, it has never been used to identify a calling marine species.
- The south pass of Fakarava Atoll, French Polynesia, hosts spawning events of many reef fish species, including the camouflage grouper Epinephelus polyphekadion, with a spawning aggregation abundance exceeding 17 000 individuals during the full moons of June and July.
- The current study aimed to use PAM to distinguish camouflage grouper sounds among the vocal activities of all fish recorded during the aggregation periods. Audio recordings analysis resulted in the identification of 29 sound types, some of which showed diel and lunar patterns.
- Temporal analysis of these sounds in relation to spawning activities allowed the identification of camouflage grouper calls. These calls can be described as a single pulse or a series of ‘boom(s)’ with a pulse duration of ~44 ms and a low dominant frequency of 103 ± 31 Hz. Video recordings show that the camouflage grouper produces the ‘booms’ to initialize spawner ascent and to promote synchronous gamete release into the water column.
- The study highlights for the first time that PAM can be used to identify the previously unknown sound of a fish species. Moreover, we can use it to understand the phenology of some biological activities for improving the resolution of fish biodiversity assessments.
20.
- the 2012 industry has a higher proportion of low and medium specialization visitors that have lower expectations and lower overall satisfaction, yet remain willing to return;
- the average per capita economic contribution of divers to the local economy and to dive companies declined by more than 30% by 2012;
- Andaman coast diving continued to grow in 2012, dominated by mass ‐ market tourism that had diversified into several niches;
- the results verify the use of the Wildlife Tourism Model as a tool to understand industry sustainability, and suggest further development of the model to capture the extension into specific, niche markets.