Journal of Aquatic Ecology

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Study was conducted to determine some biological characteristics and population dynamic of Platycephalus indicus were studied during one year from May 2011 to March 2012 in the coastal waters of Bandar Abbas. A total of 1106 samples were collected. Also, each month 35 fish was chosen and transferred to the laboratory for evaluation of spawning season. The ages of 279 specimens were determined by sectioned otoliths. The ages of the females were estimated to be between 1 to more than 7,while the ages of the males were from 1 to more than 4.The relationship between weight and length (Total length) can be expressed as W=0.004L3.16 35 for male and W = 0.0042L3.1293 for female. This equation indicates that keeled mullet has allometric growth. The values for natural mortality (M) resultant coefficient were M = 0.886 year-1 for females and 0.736 year-1 for males, and the estimated Z values were 1.43 year-1 for females and 1.62 year-1 for males. These ages were then ®tted to the von Bertalanffy growth equations. Equations obtained were Lt = 43.4 (1-exp(-0.45 (t +0.32))) for males, and Lt = 63 (1-exp(-0.50(t + 0.30))) for females.

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This study aimed to assess the ecological status of Khamir, Tiyab and Jagin creeks and the impact of human activities on the studied ecosystems using AMBI biological indicator. During the study period, 165 macro-benthos taxa belong to seven phyla including Annelids (65 taxa), Mollusca (65 taxa), Arthropods (28 taxa), Echinoderms (3 taxa), Hydrozoans (2 taxa), Nemertea (1 taxon) and Nematoda (1 taxon) were identified. For the total abundance, Polychaeta showed the richest taxonomic feature with 62 species, contributed 37.57% of the total abundance. The average values of AMBI in the four seasons ranged from 1.12±0.09 (spring) to 5.08±0.15 (autumn). The highest values occurred at station 6 (spring, 4.12±0.81; summer, 5.01±0.56; autumn, 5.08±0.15; winter, 4.42±0.38), and the lowest values occurred at stations 7 (spring, 1.12±0.09; summer, 1.24±0.07), and 1 (autumn, 1.25±0.07; winter, 1.33±0.24). Results from ecological status of studied creeks using AMBI index throughout the year showed that Khamir creek classified as "slightly polluted" to "moderately polluted", Tiyab creek classified as "slightly polluted" to "heavily polluted" and Jagin creek classified as "slightly polluted". The findings of this study revealed that the AMBI index is suitable for separation of areas with less impacted by human activities from areas affected by these activities and could be used as a robust management tool for monitoring programs.

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In the present study, the effect of different concentrations of hormone ethinyl estradiol was investigated on microalgae Cheatoceros muelleri. Seven different concentrations (250, 500, 1000, 1500, 1750, 2000, and 2500 μg/l) of the hormone were measured by a replicate control treatment. Factors including the size of chlorophyll a, specific growth coefficient, and protein content were measured in microalgae C. muelleri. The results showed that at concentrations of 250 and 500 μg/l, growth rate and chlorophyll a content in hormone-treated samples increased significantly compared to the control. In contrast, more protein was observed at the concentration of 250 μg/l than in the control group in microalgae. The results of this study showed that increasing the treatment period in most concentrations had a significant effect on growth inhibition and in some cases caused the growth of microalgae. Higher concentrations of the hormone also affected the growth inhibition, chlorophyll amount, and protein contents of C. muelleri.
 

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Sediment samples were collected from 8 sites in the northern areas of Qeshm Island, Iran to determine the total and partial concentrations of heavy metals including copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd), and Iron (Fe), in February 2016. A combination of nitric acid and perchloric acid was used to determine the total concentrations and sequential extraction method was used to analyze the partial concentrations of different geochemical parts of the sediment. Metal concentrations were measured by flame atomic absorption spectrometry. Contamination factor (CF), pollution load indices (PLI), enrichment factor (EF), geoaccumulation index (Igeo), risk assessment code (RAC) and potential ecological risk (PER) were calculated to determine the ecological risk. The results showed that the concentrations of heavy metals were Fe>Ni>Pb>Cu>Cd, respectively. The results of sequential extraction showed that Cd (25.98%) and Cu (21.40%) had the highest bioavailability among the other heavy metals. Most of each element was in the part of reducible (Fe-Mn oxide bound) (F3) and residual (F5). According to the RAC, only Cu and Cd were identified as high-risk at Station 5, and for other stations and other metals, the results showed low, medium or no risk. Evaluation of enrichment factor showed significant contamination for most of the metals tested, including Cd, Ni and Pb, which confirms the results from other indices. Finally, it can be said that the results of various indices that have been measured in relation to the mentioned heavy metals, showed that these elements have low to moderate pollution in the study area.

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The study conducted in June 2022 at Azini Lagoon aimed to assess trace element concentrations within sediment and Telescopium telescopium species. Thirty T. telescopium gastropod specimens were collected from sediment surfaces, alongside six sediment samples acquired using a plastic shovel. Analysis revealed a sequence of metals in sediment samples: Fe ˃ Ni ˃ V ˃ Pb ˃ Cd, while T. telescopium muscle tissue exhibited: Fe ˃ Pb ˃ Ni ˃ V ˃ Cd. Notably, average concentrations of nickel, lead, vanadium, and iron in surface sediments surpassed those found in T. telescopium (P≤0.05). Conversely, no significant difference was observed in cadmium concentration between sediment and T. telescopium (P≥0.05). Moreover, sediment bioaccumulation of elements was computed to be lower than one, indicating insignificant element bioaccumulation in sediment, except for cadmium, which exceeded this threshold. Enrichment values for the mentioned elements, excluding nickel, suggested no enrichment in the region's surface sediments. Additionally, calculated land accumulation values for all elements in Azini Lagoon sediments indicated a non-contaminated state, implying that these elements hadn't induced specific pollution in the area.

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This study assessed the concentrations of heavy metals—lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), and cadmium (Cd)—in the muscle tissue of Pomadasys stridens (Forsskål, 1775). A total of 60 fish specimens were collected in 2021 (year 1400 in the Iranian calendar) from two coastal locations in Hormozgan Province: Bandar Lengeh and Bandar Tiyab (30 samples from each). Biometric data, including total length and weight, were recorded prior to laboratory analysis. Muscle tissues were dried and subjected to chemical digestion, and metal concentrations were measured using atomic absorption spectrophotometry (AAS) with a graphite furnace. Results indicated significant biometric differences between the two locations, with fish from Bandar Tiab being larger than those from Bandar Lengeh. Significant differences (p < 0.05) in lead and zinc concentrations were also observed between the two sites. Overall, the concentration of all metals—except lead—was higher in samples from Bandar Tiyab. Compared to international standards and similar studies, the contamination levels suggested a low risk associated with consuming P. stridens from these regions. Additionally, no significant correlation was found between fish size (length and weight) and heavy metal accumulation.