الفهرس 
Ecological parametersOnly 14 pages are availabe for public view
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Abstract
Organisms that are associated with the bottom are collectively known as
”BENTHOS”. Bottom-living fishes may also be considered as a part of the benthos.
Truly benthic organisms are opposed to demersal species which temporarily come to the
bottom in being sessile and relatively inactive. Moreover, benthic organisms differ from
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planlctonic ones in their adaptation for association to a substrate.
Benthic animals may be described on the basis of their position in the sediments in
relation to the surface, their size, and also to their feeding type. Infauna are animals that
live within the sediments. They may move freely through the interst.itia1 spaces between
sedimentary particles, or they may build burrows or tubes. Epifauna may be attached
(sessile) or capable of movement at or on the sediment surface. Many of the species
comprising this group are mobile and frequently enter the water column (Parsons et. al.,
1984). The macrobenthic fauna comprise a diversity of animals such as annelids,
arthropods, n~olluscs, bryozoa which encrusts sea-weeds and others. Deposit-feeding
benthic communities are dominated by macro-invertebrates that ingest organic debris
and assimilate the attendant microorganisms (Fenchel 1972).