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Naití A. Morales Maike Heidemeyer Robert Bauer Sebastian Hernández Enzo Acuña Simon Jan van Gennip Alan M. Friedlander Carlos F. Gaymer 《水产资源保护:海洋与淡水生态系统》2021,31(2):340-355
- Marine protected areas (MPAs) are becoming a widely used tool for the conservation of biodiversity and for fishery management; however, most of these areas are designed without prior knowledge of the basic ecological aspects of the species that they are trying to protect.
- This study investigated the movement of two top predators: the Galapagos shark, Carcharhinus galapagensis, and the yellowtail amberjack, Seriola lalandi, in and around the Motu Motiro Hiva Marine Park (MMHMP) using MiniPAT satellite tags to determine the effectiveness of this MPA for the protection of these species.
- The Galapagos sharks (n = 4) spent most of their tag deployment periods inside the MMHMP. However, high intraspecific variability was observed in their movement dynamics. Daily individual maximum movements ranged from 17 to 58 km and the maximum distance from Salas y Gómez Island, the only emergent island within the MMHMP, ranged from 31 to 139 km.
- The maximum linear distance travelled for a female juvenile Galapagos shark (152 cm total length) was 236 km, which is greater than the maximum distance previously documented for juveniles of this species (<50 km).
- For the yellowtail amberjack (n = 1), 91% of the satellite geolocations were within the MMHMP, with a maximum daily distance travelled of 6 km. The maximum distance travelled between points was 111 km and the maximum distance from Salas y Gómez Island was 62 km.
- All archival tagged fish spent most of their time at depths of <50 m and never left the epipelagic zone. Daytime versus night-time differences were pronounced in all individuals but showed high interindividual variability.
- This study provides a baseline on the movement of these two top predators in the MMHMP and provides valuable insights for the creation of MPAs in the region and elsewhere.
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Yellapu Srinivas Anant Pande Swapnali Gole P.V.R. Prem Jothi K. Madhu Magesh Sameeha Pathan Sohini Dudhat Rukmini Shekar Chinmaya Ghanekar Devanshi Kukadia Jeyaraj Antony Johnson Samrat Mondol Kuppusamy Sivakumar 《水产资源保护:海洋与淡水生态系统》2021,31(4):818-829
- India plays a significant role in dugong conservation by having the largest population within South Asia. The status of dugongs in India is largely unknown due to a paucity of reliable ecological data. This study generated mitochondrial control region sequences from ~10% of dugong individuals from existing populations within India. Furthermore, data generated in this study were compared with the global data to assess genetic lineages, population structure, and genetic diversity of Indian populations.
- Multiple analyses suggest that the Indian dugong populations are part of a single genetic cluster, comprising South Asia, North-west Indian Ocean, and South-west Indian Ocean populations. Despite small population size, they retain high genetic diversity with unique mitochondrial DNA haplotypes within South Asia. Within India, novel haplotypes are observed from all dugong habitats sampled, with overall high haplotype diversity (0.85 ± 0.04) but low nucleotide diversity (0.005 ± 0.001). Indian populations exhibit genetic differentiation with higher within-population variance (63.41%) than among populations (36.59%). Two of the haplotypes observed in India are shared with Sri Lanka, implying genetic connectivity between these populations.
- The genetic data from Indian dugong populations provide critical insights into the identification of dugong corridors and important dugong conservation zones in India. We suggest site-specific interventions, including the creation of new marine protected areas and boundary reorganization and expansion of other existing protected areas, to ensure population connectivity. In addition, simultaneous efforts towards seagrass meadow restoration, reduction of dugong mortalities, and community participation in dugong conservation are recommended for population recovery of this threatened marine herbivore.
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1993年6~8月,“北斗”号渔业资源调查船在白令海阿留申海盆区进行了狭鳕资源声学调查及渔场环境调查。应用本航次调查资料,本文阐述了调查海区温度、盐度及溶解氧分布特征,并分析了狭鳕分布和移动与理化环境的关系。结果表明:(1)阿留申海盆区为大面积低温水所覆盖,水温在10℃以下。温盐水平分布特征为公海区低温高盐,调查区的其余水域则为高温低盐。溶解氧水平分布比较均匀,表层溶氧含量在10mg/L左右;(2)温跃层位于25米和50米之间,一强冷水团控制着100米到200米左右的水层,其水温在3℃以下。盐度随深度增加而增加,溶解氧随深度的增加而降低;(3)狭鳕当年生幼鱼主要分布在海盆水系和东大陆架水系的混合区内,100米层幼鱼密集区水温在3~5℃,盐度在32.9~33.1,溶解氧在8~9mg/L;(4)夏季狭鳕成鱼主要在冷水团范围以内垂直移动,200米层成鱼密集区水温为3~4℃,盐度为33.2~33.6,溶解氧为6~8mg/L。 相似文献
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Coastal kelp forest ecosystems provide important habitats for a diverse assemblage of invertebrates, fish and marine top-predators such as seabirds and sea mammals. Although kelp is harvested industrially on a worldwide scale little is known about the multi-trophic consequences of this habitat removal. We investigated how kelp fisheries, which remove feeding and nursery grounds of coastal fish, influence local food webs and the availability of food to a marine top predator, the great cormorant (Phalacrocorax carbo). We conducted experimental harvesting of the canopy-forming kelp (Laminaria hyperborea) during a 3 year period (2001-2003) in an area at the coast of Central Norway while synoptically monitoring fish occurrence and cormorant foraging parameters. Our results demonstrate that cormorants preferentially foraged within kelp-forested areas and performed significantly more dives when feeding in harvested versus un-harvested areas suggesting lower foraging yield in the former case. In kelp areas that were newly harvested the number of small (<15 cm) gadid fish was 92% lower than in un-harvested areas. This effect was persistent for at least 1 year following harvest. To our knowledge, this is the first time that the ecological consequences of kelp harvesting have been tested at a multi-trophic level. The results presented strongly suggest that kelp harvesting affects fish abundance and diminishes coastal seabird foraging efficiency. Kelp fisheries are currently managed in order to maximize the net harvest of kelp biomass, and the underlying effects on the ecosystems are partly ignored. This study calls for re-assessment of such management practices. 相似文献
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R.A. Stillman J.J. Moore M.D. Murphy K.R. Vanstaen W.G. Sanderson 《Biological conservation》2010,143(11):2617-2630
We use an individual-based model to assess the conservation objectives for knot Calidris canutus L. and oystercatcher Haematopus ostralegus L. on the Burry Inlet Special Protection Area (SPA), UK. Population monitoring has identified a decline in oystercatcher numbers, but cannot determine whether this is due to a decline in site quality. Long term data on cockle stocks show that the biomass of the large-sized cockles consumed by oystercatcher declined after 2004, whereas a similar decline was not observed in the smaller cockles consumed by knot. The model postdicts that during the winters of 2005/2006 to 2008/2009 the site was unable to support the number of oystercatcher present at the time it was designated (i.e. the SPA population). Large cockle biomass remained low during 2009/2010, but increases in mussel biomass meant that the model postdicted that the site could support the SPA population of oystercatcher. Knot food supplies remained high during most years, except 2008/2009 during which the model postdicted that the SPA population could not be supported. The model postdicted that the stock reserved for oystercatchers after shellfishing needed to be 2-4 times the amount consumed by the birds in order to support the bird population. We recommend that where necessary, the conservation objectives of waterbirds should be assessed using a combination of thorough population size and behaviour monitoring to identify sites with population declines, and individual-based modelling on these sites to determine whether reduction in site quality may contribute to the site-specific population decline. 相似文献
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The preliminary results of a study of the endemic giant tortoise population of Aldabra Atoll in the Indian Ocean (Geochehne gigantea Schweigger) are briefly described. Their number would appear to have increased dramatically since the turn of the century to their present level of some 141 000 individuals. Crude estimates of mortality and reproductive rates are also given. 相似文献