Identification, diversity and distribution patterns of fish larvae in Khark & Kharko Coralline Islands ecosystem – Persian Gulf, by GIS method

Khark & Kharko Islands are the last Northern point for fringing coral reefs in Iranian side of the Persian Gulf. These Coralline habitats are the Protected Area and Wildlife Refugees with the total area of 2400 ha which located in the territory of Bushehr Province. This research carried out during 2006-2007 with monthly sampling from 12 stations, which selected around Islands and inshore waters with maximum depth of 20 meter. Sampling was conducted using by Bongo-Net plankton sampler with 500μ of mesh size. Totally, 1808 specimen from 45 family fish larvae was identified in studied area, including: 21 coralline fish larva families and 24 shore fish larvae such as pelagic and demersal fishes which some of them known as indicator, sentinel or endemic species for coral reef ecosystems. The results was shown that coral reef diversity in coral reefs (Khark & Kharko Islands) is more than other habitats such as estuary and river mouth, creeks, mangrove forest sites, and off shore water of the Persian Gulf and Oman Sea Iranian side. Among Identified families, Clupeidae, Blenniidae, Sillaginidae, Atherinidae and Tripterygiidae; with more abundance were dominant families in studied area. The pick of fish larvae abundance family were estimated in spring. There were significant differences between seasonally abundance and sub areas, but there were not significant differences in diversity indexes between Khark and Kharko stations with coastal stations (p< 0.05). The mean abundance of fish larvae were estimated 18.7083 larvae under 10m² of sea surface, and the mean diversity indexes and evenness were estimated 0.7135 and 0.565342 consequently, that was showed the area is under ecological stress for fish larvae, and wasn’t stable. Therefore, from the ecological point of view, only some of the fish larvae groups as like Clupeidae were dominant. Thus, they were the main cause of the fish larvae abundance change in studied area. Due to geographical location of Khark and Kharko Islands and among the environmental parameters, Its seems that the condition of sea current is the main cause for present or absent and distribution patterns of fish larvae in area. Abundance of fish larvae in west of Islands was higher than eastern parts in the spring. But this condition will be reversed in eastern part of Island and several coastal stations, so that the Islands surrounding clock wise current to cause fish larvae distribution patterns.

The possible identification and introduction of metallothionein in Persian Sturgeon (Acipenser persicus)

Due to anthropogenic activities, toxic metals still represent a threat for various marine organisms. Metallothionein (MT) and cadmium concentration in gills, liver, and kidney tissues and cadmium partitioning in soluble (cytosol) and insoluble fractions of mentioned tissues of Persian sturgeon (Acipenser persicus) were determined following exposure to sub-lethal levels of waterborne cadmium (Cd) (50, 400 and 1000 μg L-1) after 1, 2, 4 and 14 days. The increases of MT from background levels in comparison to controls were 4.6-, 3-, and 2.8-fold for kidney, liver, and gills, respectively after 14 days. The matallothionein concentration in liver was in the range of 56.89-168.44 μgL-1 and for kidney and gills, 39.78-189.30 and 28.15-91.20 μgL-1, respectively. The results showed that MT level change in the kidney is time and concentration dependent. Also, cortisol measurement revealed elevation at the day 1 of exposure and that followed by MT increase in the liver. Cd concentrations in the cytosol of experimental tissues were measured and the results indicated that Cd levels in the cytosol of liver, kidney, and gills increased 240.71-, 32.05-, and 40.16-fold, respectively 14 days after exposure to 1000 μgL-1 Cd. The accumulation of Cd in cytosol of tissues is in the order of liver > gills > kidney. Spearman correlation coefficients showed the MT content in kidney is correlated with Cd concentration, the value of which is more than in liver and gills. Thus, kidney can be considered as a tissue indicator in Acipenser persicus for waterborne Cd contamination. Also, tissue metal accumulations (gills, liver, kidney and muscle) in Persian sturgeon (Acipenser persicus) were compared following exposure to sublethal levels of waterborne Cd (50, 400 and 1000 μg L-1) after periods of 1, 2, 4 and 14 days. Meanwhile, the trends of Cd concentration increase in different tissues during the exposure periods and concentrations were modelled as equations. The obtained results indicate that at the end of 4 and 14 days of exposure, total tissue cadmium concentration followed the pattern: liver> gill> kidney> muscle. Calculation of bioconcentration factor (BCF) after 14 days exposure showed that at low and high concentrations, highest BCFs were found in kidney and liver, respectively. According to the results, the accumulation capacity of muscle was the lowest at all exposure concentrations. The hematological parameters including osmolarity, total protein, cortisol and glucose of plasma were measured, too. Total protein of plasma was in the range of 416.90-1068.10 mg dl-1 plasma.Total protein decreased not significantly (P≥0.05) after exposure to Cd. Cortisol increased after 1 day exposure that followed by significant (P≤0.05) elevation of glucose. The range of cortisol was very vast and it was determined between 0.03 to 16.21 ng mL-1. The content of plasma osmolarity was in the range of 282.33-294.20 mOsmol L-1.Osmolarity of treated fish plasma showed no significant decrease (P≥0.05). Total protein in gills, liver, and kidney showed that at high concentrations of metal, protein content decreased significantly (P≤0.05) in the liver after 4 and 14 days exposure. Thus, total protein of liver and glucose of plasma can be used as general biomarkers of exposure to Cd. Also, the metallothionein and cadmium were measured in gills, kidney and liver of 8 wild Persian sturgeon caught in coast of Guilan Province. According to the results, the concentration of metallothionein was in the range of 45.87-154.66 microgram per liter with the maximum and minimum concentrations in liver and gills, respectively. The trend of cadmium concentration in cytosol of tissues was: liver> kidney> gills. The results of Spearman correlation test showed that there was a significant positive correlation between metallothionein and cadmium in cytosol of liver (r2= 0.850, p≤ 0.01). In the kidney, the correlation between cadmium and metallothionein was significantly positive (r2= 0.731, p≥ 0.05). But there was not such significant correlation in the gills (p≥ 0.05).