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نتیجه جستجو - Benthic fauna

تعداد مقالات یافته شده: 2
ردیف عنوان نوع
1 Comparability between box-corer and epibenthic-sledge data on higher taxon level: A case study based on deep-sea samples from the NW Pacific
مقایسه پذیری بین جعبه هسته و داده های سورتمه کششی در سطح تاکسون بالاتر: یک مطالعه موردی بر اساس نمونه های در اعماق دریا از NW اقیانوس آرام-2020
The vastness and difficult accessibility of the deep sea, together with the previous thought that it harboured no life, has hampered research in this environment until the nineteenth century, when the exponential discovery of new species was rapidly combined with the development of new gears to explore the deep-sea fauna. Nevertheless, apparatuses developed in the twentieth century are still used to sample benthic organisms nowadays. Among them, box corers (BC) and epibenthic sledges (EBS) are the most common ones applied in macrofaunal studies. In this study, the comparability between these two gears from samples collected at the deep NW Pacific was tested by means of non-permutational ANOVA. Using uni- and multivariate analyses, we tested whether significant differences could be found between gears using the univariate indices: high taxa richness, total abundance, evenness, estimated number of taxa, and Shannon diversity; and the multivariate indices: total abundance, presence|absence, and relative abundance. Results indicate that both gears can be comparable when evenness, estimated number of taxa, and Shannon diversity (univariate indices) are used, as well as relative abundances based on the multivariate data matrix. This means that data derived from the EBS can be used in a quantitative way, for e.g. in an ecological context, up to a certain extent. On the other hand, significant differences between BC and EBS were found for total abundance and species richness. This could be a result of the bigger amount of sediment the EBS collects together with a larger sampled area by this gear, consequently leading to a higher amount of organisms and taxa sampled. Moreover, despite the interchangeability between these two gears was possible for some indices at higher taxa level, caution should be taken into account when comparing data for other deep-sea areas and at species level.
Keywords : Benthic fauna | Kuril-Kamchatka Trench | deep-sea gears | sampling techniques | ecological indices
مقاله انگلیسی
2 Assessment and management of the North Brazil Shelf Large Marine Ecosystem
ارزیابی و مدیریت از شمال برزیل فلات بزرگ دریایی-2017
The North Brazil Shelf is a Large Marine Ecosystem (LME) that extends from the Caribbean Sea, in Central America, to the Parnaiba River in Brazil, and includes six countries. The area is dominated by the runoff of large rivers, including the Amazon and Orinoco, and by the intense disturbance of sediment transport, tides and currents. The sea bed is formed mainly by mud in shallow water, and by sand, mud, and gravel in deeper water. In terms of its biological productivity, this LME can be considered oligotrophic, with stratified habitats. The main source of nutrients of the euphotic layer is the local rivers and mangroves. Primary production has been limited by light and rising temperatures in recent years, factors associated with a decrease in marine primary productivity. However, the benthic fauna is very rich and unique, but poorly known. More than 500 fish species have been recorded in this LME. Demersal fish and shrimp are the main fishery resources in coastal and continental shelf waters. Fisheries account for more than 600 million USD a year with a considerable diversity of methods and scales ranging from very small to industrial. Seafood consumption is moderate to high in the local countries. Climate changes, dam building, deforestation, pollution, overfishing, tourism and aquaculture are the main threats to ecosystem productivity and habitat quality. Socioeconomic data are scant for this LME. Development is concentrated near the cities and mouths of rivers. Traditional commu nities in the coastal areas are culturally diverse, but invariably characterized by very low socioeconomic conditions. The Gross Domestic Product of the local countries ranges from 7,500 USD per capita in Guyana to 32,600 USD per capita in Trinidad and Tobago. Profound problems of governability are common to all six countries, and mean governance indicators reflect poor performances in all cases. The main issues are an absence of effective rule of law, political stability, and control of corruption. Fisheries are characterized by increasing effort and an absence of sustainability. Most of the fishery stocks are either fully or over exploited. This scenario can only be rectified by investments in marine protected areas and scientific research, as well as the increased participation of fishers in the development and implementation of management strategies and regulations.
Keywords: Fisheries | Governance | Ecosystem Based Management
مقاله انگلیسی
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