Application of biotic indices in assessing the ecological quality status of Bahrekan estuary (Persian Gulf)

The aim of present study was to examine the macro invertebrates as an assessment tool for characterization of the state of Bahrekan estuary in Persian Gulf, by using different biotic indices. An investigation on benthos was carried out during autumn 2008 to summer 2009 in the Bahrekan estuary (Persian Gulf). In order to identify and assess the benthic community structure, seasonal sampling was done from 21 stations with three replicates using van veen grab (./285 m2). The ecological indices, such as (AMBI, BI and Bentix), Shannon-Wiener index (H'), species richness (S) were applied to the available benthic species data, and evaluated comparatively. The grain size of sediments and total organic matter as essential factors in distribution and population diversity of macrobenthos communities were also analysed. According to the results, 17 groups of macrobenthos were identified. Out of 111 genus/species identified in this study, Gastropoda was the dominate group (79.8%), followed by Bivalvia (5.5%). Pyrgohydrobia sp. belonged to gastropoda was dominant in all of seasons. The results showed that all of the stations are characterized as muddy bottom and Bahrekan estuary are classified in slightly to moderate pollution status.

Morphology of the zoeal stages of Hexapus sexpes fabricius, 1798 (decapoda, brachyura, hexapodidae) reared in the laboratory

Abstract: The present information is based on the study of the zoeal stages of Hexapus sexpes. A single ovigerous female of Hexapus sexpes was collected from the North West Persian Gulf (29 degrees 56'14"S, 49 degrees 0288"W) in April 2009. Female was maintained in aquarium containing natural sea water at 25 degrees C until the eggs hatched. The present study describes the zoeal stages of Hexapus sexpes. A complete description and illustration of larval features is provided and a comparison with closely related species (Spiroplax spiralis and Lambdophallus anfractus) showing known larval development is presented. The zoeal stages of H sexpes are very similar to that of L. anfractus. The zoeal of two species, however, could separate by the number of setae on the maxillule and maxilla.

Applying Benthic Index of Biotic Integrity in a soft bottom ecosystem in North of the Persian Gulf

In this study, the Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI) was selected in an attempt to describe ecological health of soft bottom channels (Khowr-e Musa) in North of the Persian Gulf. Most of study area was found to be in degraded or severely degraded conditions. B-IBI scores were ranged between 1 and 3.86. Comparison ofmacrobenthos abundance and organic content between two developmental periods showed significant difference (p < 0.05). After the establishment and development of petrochemical industries, the abundance of macrofauna decreased (809 to 239 individuals m(-2)) and organic content increased leading to organic enrichment (15.3 to 22.4%). Three new sources of organic matter were found to be important namely industrial waste, sewage and mangrove litter. After 1999 about 6 millions Avicennia marina tree were planted near petrochemical zone in the area. Study area changed rapidly in the last decade and region is under severely anthropogenic impacts. The present study showed that Khowr-e Musa is under both natural stress and anthropogenic impacts and two main impacts could be attributed to the organic enrichment and to the dredging. Choice of suitable management plans and metric controls could help to the salvage of the largest tidal channel complex in Persian Gulf.

The food habit of Epinephelus coioides (Hamilton, 1822) in Khuzestan coastal waters (Persian Gulf)

During January 2000 to March 2001, a large number of Epinephelus coioides species was captured in main fishing areas of Khuzestan province namely, Busafe-Liphe and Bahrakan, North of Persian Gulf. The stomach contents of 394 individuals were analysed, in which 226 individuals had contained (trace-full) stomachs while 168 individuals had empty stomachs. The percentages of CV in males were more than in females. Seventy three percent of stomachs contained fish 11% crab; 8.8% shrimp; 3.9% squid; 1.7% gastropod and 0.4% bivalves. The intensity of feeding in monthly sampling periods and length groups did not show a clear trend. The results of Fp index showed 73% for fish; crab 11%; shrimp 8.8%; squid 3.9%; gastropod 1.7 and 0.4% for bivalvia. Similar pattern of feeding was observed using CN index. The main food items for E. coioides were fish followed by crabs and accidental food items were shrimp, squid, gastropods and bivalvia.