Iranian Journal of Ichthyology

Feeding characters of Alburnus sellal (Family: Leuciscidae) in the Little Zab River, western Iran

2023-12-25T13:07:05+00:00

The feeding characteristics of Alburnus sellal in the Little Zab River, west Azarbaijan Province, Iran were studied from November 2021 to October 2022. The specimens were collected and anesthetized in 1% clove oil, fixed in 10% buffered formalin, and transferred to the laboratory. The average condition factor for males and females was 0.85 showing a significant difference between different months in both sexes (P<0.05). The average length and weight for all specimens were 11.36±1.95cm and 11.8±7.14g, respectively. The average length of gut (RLG) for all fish was 0.65±0.11 during the year. The mean RLG in different months showed significant differences (P<0.05). The highest Gastrosomatic index value was recorded in January and those lowest in August and showed significant differences in different months (P<0.05). A total of 34 empty stomachs were observed amongst the 95 specimens and there were significant differences in different months (P<0.05). This species is an omnivorous fish that mainly consumes aquatic insects, aquatic plants, algae, diatoms, and organic decay material with modest feeding throughout the year.

Habitat suitability projections for the Black Pomfret (Parastromateus niger) under climate change: an ensemble modeling approach

2023-11-06T11:02:01+00:00

Marine ecosystems are under serious threat from climate change, which can alter species distributions, biodiversity patterns, community structure, and ecosystem functioning by affecting temperature, acidification, and current patterns. Species distribution models (SDMs) are a useful tool for ecologists to link species’ fundamental niches with environmental conditions and project potential distribution shifts under climate change scenarios. This study modeled current and future habitat suitability for the black pomfret (Parastromateus niger) using an ensemble SDM with 1,396 occurrence records and environmental data layers (depth, temperature, salinity, currents). Six algorithms (MAXENT, GAM, GLM, RF, ANN, MARS) with ensemble approach modeled species distribution under current and future semi-optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios for both 2050s and 2100s. Models were evaluated by AUC, TSS and Cohen’s Kappa indices. According to the results, future range changes under all optimistic and pessimistic scenarios were negative. These results reveal prospective climate change impacts on the geographic range of P. niger, providing a valuable basis for science-based adaptation initiatives aimed at ensuring long-term sustainability of populations. Localized conservation and global mitigation policies are urgently needed to sustain P. niger and reliant human communities into the future. Habitat modeling supports climate-resilient management strategies for threatened marine species.

Forecasting the catch of the stocks of Persian sturgeon (Acipenser persicus Borodin 1897) in the southern shores of the Caspian Sea using DB-SRA and dynamic model

2023-12-10T05:45:59+00:00

This study aims to analyze the fishing trend and predict the future catch of Persian sturgeon (Acipenser persicus) stocks by DB-SRA and dynamic models in the southern shores of the Caspian Sea. The results showed that, according to the size of the initial population in 2018, equal to 153 spicemens (mean weigth 30kg); assuming a constant rate of catch from the population equivalent to 0.2 per year (half of the current catch); until the next 30 years (2050), the amount of catching of Persian sturgeon will increase until the stocks of this species have the ability to fully restore themselves. While assuming the current catch rate, there has been a sharp decrease in the catch of fish in the southern shores of the Caspian Sea; it is estimated that the stocks of this type of sturgeon fish will be extinct by 2050.

Distribution pattern of total mercury (T-Hg) in muscle, liver and spleen of Pike (Esox lucius) in Anzali wetland, Caspian Sea

2023-11-18T14:28:32+00:00

The present study aimed to investigate the bioaccumulation of total mercury (T-Hg) in dorsal muscle (edible tissue), liver, and spleen of pike (Esox lucius) from Anzali Lagoon, Iran. Acceptable monthly intakes (AMI) were measured based on FDA criteria. Sampling were carried out using gillnet and electro-shocker from July 2020 to July 2021. In addition, 78 specimens (age range 1-5 yr; total length: 10-58^cm; weight: 12-1560g.) were collected. Samples were analyzed by LECO AMA254. The measurements were conducted according to the following procedures: drying time 70s, decomposition time 120 s at 600°C in an oxygen atmosphere, and waiting time 50s. The same procedure was used with a blank sample. Each series was preceded by measuring the form of T-Hg in the certified reference material according to ASTM standard NOD-6722 with three standard reference material; SRM 1633b, 2709 SRM and 2711 SRM in three replications. Accuracy degree ranged from 95.5 to 105%. Detection limits was 0.001 mg/kg in dry weight. The min and max of T-Hg in dorsal muscles were ranged between 0.2 and 1.2ppm. The min T-Hg significantly increased with age increased (P<0.05). T-Hg concentration in muscles were significantly higher than liver and spleen (P<0.05) and higher in females than males (P<0.05). T-Hg distribution pattern in tissues was as follows: muscle> liver> spleen (P<0.05). AMI estimates for women, men, teenager and children as 270, 320, 125, and 59g, respectively.

Chlorpyrifos induced oxidative stress responses and alteration of acetylcholinesterase activity in the olfactory organ of freshwater minor carp, Labeo bata

2024-01-24T11:19:57+00:00

The sub-lethal toxicity of Chlorpyrifos on selected oxidative stress biomarkers (malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), and reduced glutathione (GSH)) and acetylcholinesterase (AChE) activity was examined in the olfactory organ of Labeo bata under sub-lethal exposures. Chlorpyrifos (CPF) was administered at predetermined exposure concentrations (21.93 and 36.54µg/L) and monitored on days 15 and 30 of the experimental periods. The experimental groups showed significantly higher values (P<0.05) of MDA, SOD, CAT, GST and GPx in CPF exposed fish compared to control. AChE and GSH were significantly lower in exposed fish. In general, biomarker depictions indicate that CPF exposures are capable of inducing stress-specific effects at the biochemical and physiological levels negatively impacting the overall health and longevity of such animals.

DNA Barcoding of venomous stonefish (Pseudosynanceia melanostigma) from the Persian Gulf

2024-01-13T08:48:22+00:00

Stonefish (Pseudosynanceia melanostigma), a species of the family Synanceiidae, which is considered the most venomous fish and a source of potential pharmaceuticals, is found in the muddy bottoms of the shallow waters of the Persian Gulf. This study presents the first barcode sequences of P. melanostigma in global gene databases from the Persian Gulf. The specimens were identified based on morphological characteristics as well as DNA barcoding based on the COI gene. The present record of this species as a reference in gene databases adds to our knowledge of the biodiversity of fish globally and could be used as an effective tool in the future for the accurate identification of fish at any stage of the life cycle or even for the identification of this species in other regions.