فصلنامه بوم شناسی آبزیان
سال سیزدهم شماره 2 (پیاپی 49، پاییز 1402)

In light of limited biological data, particularly concerning the dietary habits of four-lined terapon fish (Pelates quadrilineatus), a comprehensive study was conducted. A total of 140 fish samples were gathered from various points along the Makkoran coast, including the Chabahar fish market and catch unloading centers in Chabahar, Ramin, and Tis. The investigation aimed to delineate their seasonal feeding patterns from the onset of summer 2019 until the conclusion of spring 2020. The findings revealed the average total length and weight of the fish to be 18.51±4.13 cm and 82.30±16.71 grams, respectively. Moreover, the average relative length of the intestine and stomach fullness/emptiness stood at 0.52% and 49.29%, respectively, indicating the species' carnivorous nature and moderate feeding tendencies. Notably, gastro-somatic index, feeding intensity, and condition factor during autumn were significantly lower than in other seasons, with averages of 1.48±0.24, 95.34±25.11, and 0.72±0.068, respectively (p<0.05). Assessment of food preference and relative importance unveiled mollusks and crustaceans as primary dietary components, with copepods, polychaetes, and fish identified as secondary sources for this species. Among mollusks and crustaceans, the gastropod and hermit crab held the greatest significance, accounting for 41% and 42% of the P. quadrilineatus' diet, respectively. Overall, the feeding indicators suggest that this species thrives as a carnivorous fish, exhibiting moderate feeding habits and favorable living conditions in the coastal waters of Makkoran

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.

The study delved into bacteriocins, peptides with antibacterial properties, originating from select lactic acid bacteria. Isolating 18 such bacteria from Liza klunzingeri's intestine, their potential in bacteriocin production against food pathogens was assessed. Crude bacteriocins from 7 isolates exhibited the ability to inhibit food pathogens via an agar spot test. Notably, bacteriocins derived from LK5 and LK12 isolates displayed a broader inhibitory spectrum against the pathogens under study. Further analysis revealed that the studied bacteriocins were susceptible to proteolytic enzymes, leading to complete degradation. However, these bacteriocins retained their antibacterial potency when subjected to diverse detergents, pH variations, and temperature fluctuations. Genetic analysis via the 16S rRNA gene identified LK5 and LK12 as strains of Lactobacillus plantarum, with similarity percentages of 98.55% and 99.46%, respectively. The findings highlight L. Klunzingeri's intestinal bacterial flora as a promising source for isolating bacteriocin-producing bacteria. Specifically, bacteriocins derived from L. Plantarum LK5 and L. Plantarum LK12 showcase potential as biological preservatives within the food industry, warranting further exploration.

The study aimed to assess temporal and spatial variations in the population of polychaetes, a significant invertebrate group in deep-sea ecosystems, across the northern waters of the Persian Gulf and the Oman Sea. Sampling occurred from fall 2018 to winter 2020, covering regions in Hormozgan, Bushehr, Sistan and Baluchestan, and Khuzestan. A total of 115 stations were surveyed, utilizing 0.1 square meters and a 500 μm sieve (repeated thrice) to collect bed sediments within the depth range of 12 to 90 meters. Within this study, 35 species/genus of polychaetes were identified in the waters of the Persian Gulf and the Oman Sea. Notably, Flabelligra sp., Manayunkia aestuarina, and Glycinde sp. exhibited the highest abundance, with Flabelligra sp. and M. aestuarina serving as indicator species in both regions. The provinces of Sistan and Baluchestan and Bushehr displayed the highest Shannon diversity and species richness, recording 3.592 and 6.998, respectively. Comparing these findings with prior reports revealed a reduction in the diversity of identified polychaete species in the Persian Gulf. This decline could stem from various factors such as habitat damage due to fishing equipment, and the incidence of contaminants. Continual research and database establishment for time series analysis could significantly aid researchers, authorities, and environmental advocates in comprehending the health status of the Persian Gulf and the Oman Sea. Such efforts would facilitate environmental monitoring and pollution prevention measures, contributing to the preservation of these ecosystems

Aquatic and semi-aquatic plants are vital components of aquatic ecosystems, contributing significantly to their ecological balance. This study focused on the analysis of marginal plants along the Arvandroud, conducting seasonal samplings with 1 x 1 square meters and 3 repetitions at each station across two periods: summer 2015 and winter 2016. The collected samples underwent pressing for herbarium studies. The survey identified 25 plant species spanning 11 families. Among these, 5 were monocotyledonous, encompassing Poaceae and Cyperaceae, while 18 were dicotyledonous, including Lamiaceae, Capparaceae, Fabaceae, Asteraceae, Convolvulaceae, Apocynaceae, Amaranthaceae, Tamaricaceae, and Polygonaceae. Notably, the dominant marginal plants observed during summer were Phragmites australis (Cav.) Trin. Ex. Steudel and Cyperus longus L., while in winter, it was Phragmites australis, Cyperus longus, and Senecio glaucus L. Phragmites australis emerged as the dominant species based on its density across both seasons. Principal Component Analysis (PCA) revealed the influential environmental factors affecting these plants, with sediment particles, total organic matter, salinity, and electrical conductivity identified as the most significant. Interestingly, plant density was higher in winter compared to summer, highlighting seasonal variations in plant distribution along the Arvandroud.

The study aimed to examine the chronic toxicity effects of oxytetracycline (OTC) and florfenicol (FLO) antibiotics, commonly used in shrimp farms, on the growth performance, chlorophyll a content, and total protein of Chaetoceros muelleri microalgae. C. muelleri, initially at a density of 4,000 cells per milliliter, underwent exposure to oxytetracycline at doses of 7.43 milligrams per liter and florfenicol at 5.20 milligrams per liter for 12 days. Subsequent assessments focused on growth metrics, chlorophyll a content, and total protein. The findings highlighted a significant reduction in the growth, chlorophyll a content, and protein synthesis of C. muelleri following exposure to both OTC and FLO antibiotics (p < 0.05). Moreover, the study revealed that FLO exhibited higher toxicity toward C. muelleri compared to OTC. The observed decline in growth, chlorophyll a content, and protein synthesis in C. muelleri under OTC and FLO exposure could be attributed to the inhibitory impact of these antibiotics on cellular respiration and protein synthesis pathways.

The study aimed to assess the impact of Glycyrrhiza glabra extract on IGF, TNF, and lysozyme gene expression in Cyprinus carpio. Fish, averaging 9.08±0.05 grams, were distributed across 12 tanks and subjected to three levels of G. glabra extract (0, 0.5, 1, and 2 %) over a 56-day feeding period. Results at the study's conclusion revealed that G. glabra extract notably enhanced growth factors, including final weight (FW), weight gain (WG), and specific growth rate (SGR). The most significant growth was evident in fish fed 2% of the extract, displaying substantial differences compared to both the control and other treatments (P<0.05). Treatment with 2% also demonstrated the lowest Feed Conversion Ratio (FCR), indicating efficient feed utilization. Regarding gene expression, the study found an upregulation of the IGF gene in fish treated with 2% of G. glabra extract compared to the control group. TNF gene expression showed its highest levels in fish fed 0.55 of the extract, while lysozyme gene expression exhibited notable differences specifically in the 2% treatment. Overall, the findings suggest that G. glabra extract positively influences growth by enhancing IGF gene expression and supporting the immune system in C. carpio.