الفهرس 
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Abstract
The present study aims to determine the presence
and diversity of the species composition of macroinvertebrate fauna: Cnidaria, Crustacea, Mollusca and
Echinodermata inhabiting the mangrove ecosystem
(Avicennia marina) at Nabq and Ras Mohamed
Protectorates, South Sinai. Moreover, the distribution,
status, overall abundance, seasonal variations, Population
Density, Species Richness, zonation, and similarity in
faunal composition between the different studied sites are
also considered. The specimens of the present work are
collected seasonally (summer, autumn, winter and spring)
from five mangrove swamps, one from Ras Mohamed
protectorate and the other four swamps from Nabq
protectorate named Gharqana, Arwashia, El-Manqata and
Abu Zubad.The present study showed the following results:
1- Ecological Parameters of Ras Mohamed and Nabq
Protectorates:
Water temperature fluctuated between 21–23°C in
winter and 29.5–33°C in summer. Changes in air
temperature followed the same pattern but are slightly
higher than water temperature in autumn, winter and
spring but lower in summer. Approximately there is
slightly a change in the pH values of water in mangrove
swamps ranged between 7.5 – 8.3 in summer and winter,
respectively. Seasonal changes in the concentration of
dissolved oxygen in the studied sites indicate that it
ranged between (5.4 – 7.3) mg/L. The minimum value is
recorded in summer and the maximum value is recorded
in winter. Changes in salinity are observed; it ranged
between 39.04 ppt. in winter and to 51.48 ppt. in summer.
During the present study, three types of habitats at
mangrove ecosystem: rocky, sandy and muddy habitats are accommodated different species of macroinvertebrates.
2- Macro-Invertebrates of Mangrove Ecosystem in Ras
Mohamed and Nabq Protectorates, South Sinai:
The list of the recorded macro-invertebrate species
comprised 122 species belonging to 97 genera, 59
families, 16 orders: Rhizostomeae, Decapoda,
Archaeogastropoda, Basommatophora, Cephalaspidea,
Heterobranchia, Heterostropha, Littorinimorpha,
Mesogastropoda, Neogastropoda, Arcoida, Mytiloida,
Pterioida, Veneroida, Chitonida and Ophiurida, six
classes: Scyphozoa, Malacostraca, Gastropoda, Bivalvia,
Polyplacophora and Ophiuroidea and four phyla:
Cnidaria, Crustacea, Mollusca and Echinodermata.
Mollusca have the highest number of species,
being 108 species (88.6%) belonging to 86 genera and 50
families: 69 species of Gastropoda, 38 species of
Bivalvia and one species of Polyplacophora. Crustacea is the second group, it is represented by 11 species (9%)
belonging to 9 genera and seven families, of which nine
species of Brachyura and two species of Anomura.
Phylum Echinodermata comes after Mollusca and
Crustacea, it represented by two species (1.6%) belonging
to one genus. The lowest number of recorded species is
belonging to phylum Cnidaria and represented by one
species (0.8%).
3- Occurrence Pattern of Macro-invertebrates in
Mangrove Ecosystem of Ras Mohamed and Nabq
Protectorates:
The number of macro-invertebrate species is
different with different mangrove sites. El-Gharqana site
in Nabq Protectorate has the highest number of species,
(92 species: 75 genera and 51 families). Abu Zubad site
is next in order and representing by 67 species (58 genera
and 37 families), followed by El-Manqata site (57
species: 50 genera and 35 families) and finally Arwashia
site has the lowest number of recorded species, (49 species: 43 genera and 35 families). The number of
macro-invertebrates species recorded from Ras Mohamed
is 55 species (46 genera and 32 families).
The status of the recorded species in such specific
habitat is markedly variable from phylum to another. For
Cnidaria and Echinodermata, the abundant species
constituted 100% at Nabq Protectorate. For Crustacea,
the abundant species constituted 72.7%. In contrast, 9.1%
and represented by one species is considered common and
the other species are rare (18.2%) at Nabq Protectorate.
On the Other hand, at Ras Mohamed Protectorate the
abundant species constituted 85.7% of the total number of
crustaceans and 14.3% represented by one species is
considered common. The molluscan species exhibit the
same pattern as in case of crustacean species; the number
of abundant species is 32 (29.9%). However, the common
species represented by 18.7% and (51.4%) considered
rare at Nabq Protectorate. Whilst, at Ras Mohamed
Protectorate the abundant species constituted 41.7% of the total number of Molluscan species, 18.7% is common
species and 39.6% is considered rare species.
A total of 29087 specimens of all species are collected
from the different sites during the present survey. Out of them
21910 specimens (75.3%) are Mollusca, 6792 specimens
(23.3%) are Crustacea, 257 specimens (0.9%) are Cnidaria and
128 specimens (0.5%) are Echinodermata.
The macro-invertebrate groups exhibit a marked seasonal
variation in their occurrence in the mangrove sites at Ras
Mohamed and Nabq Protectorates. During summer, the highest
number of species is recorded, being 90 species, of which one
species of Cnidaria, 11 species of Crustacea, 76 species of
Mollusca and two species of Echinodermata. The number of
species is declined during autumn and winter to 88 species (one
cnidarian, ten crustaceans and 77 molluscans) for the autumn,
and (one cnidarian, nine crustaceans, 76 molluscans and two
echinoderms) for the winter. During spring, the lowest number
of species is recorded, being 76 species, of which one species of Cnidaria, nine species of Crustacea, 64 species of Mollusca and
two species of Echinodermata.
The population density (number of individuals/m2) of
macro-invertebrate species in different seasons is represented in
mangrove sites of Ras Mohamed and Nabq Protectorates.
The richness value of macro-invertebrate species in Ras
Mohamed Protectorate is minimum in summer and maximum in
autumn. On the other hand, at Nabq Protectorate the minimum
richness value recorded at Arwashia in winter and maximum
value recorded at El- Gharqana in winter.
Mangrove communities of the five mangrove sites include
faunal assemblage of many species. Some groups exhibit clear
zonation in distribution (crabs and molluscs), others are just
visitors but the majority is resident in the mangrove.
The highest similarity of species is shown between
macro-invertebrates of El- Gharqana and Abu Zubad sites, being
69.18 %. Whereas, the lowest similarity is recorded between
Arwashia and Abu Zubad, being 48.28%. The other indices varied from 52.48% between El- Gharqana and Arwashia to
66.67 % between Ras Mohamed and El- Gharqana..