الفهرس 
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Abstract
The Mediterranean Sea is one of the most highly precious seas in the world and comprises a massive set of coastal and marine ecosystems. Regarding to monitoring and study the biodiversity of benthic fauna inhabited the Egyptian Mediterranean. The present study investigated the community composition, distribution, status, origin, and seasonal variation of macrobenthic invertebrates. In addition, taxonomic study was established for two newly recorded species from the eastern Mediterranean coast of Egypt. 6.1. Recorded taxa ▪ The Macrobenthic fauna in the fishery trash was collected from 18 trawling net from different localities in the Egyptian Mediterranean coast from Damietta to Bardweel Lagoon along of 180 km from July 2016 to May 2017. ▪ Sorting of collected specimen has been taken in the laboratory of biodiversity and taxonomy of aquatic biota (TBAB), national institute of oceanography and fisheries (NIOF), Alexandria. ▪ A total of 95 taxa were logged, encompassing 91 species, 95 genera, 58 families, 32 orders, 16 classes and 7 phyla of benthic macroinvertebrates. ▪ The results showed that the recorded Phyla belonged to Porifera which represented by 4 species, Cnidaria which represented by and Conclusion 143 species, Annelida which represented by 3 species, Mollusca which represented by 37 species, Arthropoda which represented by 38 species, Bryozoa which represented by 3 species and Echinodermata which represented by 7 species. ▪ Twelve newly recorded species which divided as: - Three species of Porifera (Axinella verrucose, Axinella polypoids and Chondrilla nucula). - One species of Annelidan polycheate (Paramphinome jeffreysii). - Two species of Molluscan gastropod (Armina tigrine and Philine aperta). - Six species of Arthropodian crustacea (Metapenaeopsis barbata, Processa macrodactyla, Lysmata kempi, Alpheus inopinatus, Eurycarcinus integrifrons and Heterosaccus dollfusi). 6.2. Species richness of macrobenthic invertebrates during the period of study ▪ The species richness during summer (8-12 July) showed that Mollusca was the highest group where it represented by 20 species )44%( of recorded species, followed by Arthropod (Crustacea) 19 species (42%), Echinodermata and Bryozoa represented by 5% (2 species), while each of the Porifera and Annelida represented by 2% (1 species). ▪ The species richness during autumn (10-11 November) showed that Arthropod (Crustacea) was the highest group where it represented by 19 species (38%) of recorded species, followed by Mollusca 18 species (36%), followed by Echinodermata 5 species (10%), followed by Porifera 4 species (8%) while, each of Cnidaria and Annelida represented by 2 species (4 %). ▪ The species richness during winter (15 January and 2 February) showed that Arthropod (Crustacea) was the highest group where it represented by 21 species (60%) of recorded species, followed by Mollusca 12 species (34%) while, each of Echinodermata and Porifera represented by 1species (3%). ▪ The species richness during spring (21 May) showed that Arthropod (Crustacea) was the highest group where it represented by 13 species (62%) of recorded species, followed by Mollusca 5 species (24%) followed by Cnidaria by 2 species (9%) meanwhile, Porifera represented by 1species (5%). 6.3. Origin and status of recorded taxa The present study reported that 51 (54.8 %) of recorded macrobenthic invertebrate species were indigenous and 42 (45.2 %) of recorded species were alien species. Meanwhile, the native range of the recorded taxa was most commonly the North Atlantic Ocean (58.1%), followed by the Indo-Pacific (20.9%), then the Indian Ocean (7 %) and other small origin ratios. 6.4. Seasonal variation ▪ The total number of individuals sorted from 18 haul amounted to (8238 individual), whereas, the highest number of individuals per haul (1568 ind. /haul) was recorded for haul 15 during winter, meanwhile, the lowest number of individual (116 ind. /haul) was recorded for haul 8 during autumn. ▪ The maximum value of D- index was recorded during Autumn and the minimum value estimated during winter, moreover, the maximum value of equitability (J) was also recorded during autumn meanwhile, the minimum value estimated during winter. ▪ The maximum value of H- index was recorded during Autumn while the minimum value estimated during winter. Moreover, the maximum value of evenness (lnH/s) was estimated during spring and the minimum value also estimated during winter. ▪ The highest species richness value was recorded during autumn and the lowest value recorded in spring. Meanwhile, the highest abundant value was recorded in winter and the lowest value recorded during autumn. As well as the highest dominancy was recorded for winter followed by spring then summer and autumn. ▪ The most abundant phylum during the period of study was Arthropoda followed by Mollusca, Echinodermata and Porifera then the other groups. ▪ As a unique species the Mollusca was the most diverse (24 unique taxa identified over 18 hauls), followed by the Echinodermata (5 unique taxa), the Cnidaria (4 unique taxa), and then the Annelida (3 unique taxa) and only 2 unique taxa of Bryozoa were observed. ▪ The highest degree of similarity (74.80) was identified between haul 17 and haul 18. Meanwhile, the lowest similarity degree (2.16) was recorded between haul 8 and haul 14. ▪ Significant PERMANOVA (p=0.001) and non-significant PERMDISP (p=0 0.085) reflected that, there was a difference in the location of the samples (i.e. the average community composition) among seasons. Whereas, A relative grouping between spring and summer was visible at a similarity threshold of 48%. Therefore, samples taken at H5 in summer and H8 in autumn seemed to show more different community compositions than others. ▪ BEST analysis showed that the environmental variables that best explained or correlated with the patterns of biological data were depth and temperature. Furthermore, DistLM analysis revealed that the model including depth and temperature explained 30.62% of the variation of biological community data. In this model, both the two parameters contributed significantly. ▪ Canonical correspondence analysis (CCA) demonstrated a clear correlation between the abundance of macrobenthic invertebrates and each of water temperature, water salinity and depth. Whereas, the relatively small magnitude of salinity vector indicated that this parameter was not as strongly correlated to species composition as depth and temperature. In general, almost recorded species showed high fidelity to shallow water and high temperature. Meanwhile, few species showed fidelity to deep water.