Iranian Journal of Ichthyology
Volume:9 Issue: 3, Sep 2023

To understand the bioaccumulation of trace metals in greater lizardfish, Saurida tumbil in Iraqi marine water, fish were monthly collected from May 2021 to April 2022. Heavy metals, including Pb, Ni, Fe, Co, and Cu in surface water, food web, and fish tissues were analyzed. The food of S. tumbil included three fish, crustacea, and squid. Surface water Pb and Fe concentrations were higher during the year, ranging from 10.5±2.83 to 19.98±3.69μg/L and 24.77±2.99 to 29.08±2.67μg/L, respectively. The concentration of heavy metals in different food webs showed that Fe and Pb were higher in fish, Cu was higher in fish and shrimp, and Co was highest in squid. The highest concentration of heavy metals (Pb, Ni, Fe, Co, and Cu) in lizard fish tissues was found in the summer. The food web was responsible for the greatest accumulation of Pb and Ni, in the tissues of lizard fish during summer and winter, whereas seawater was responsible for the greatest accumulation of other trace metals (Fe, Co, and Cu). Heavy metal accumulation in tissues of greater lizardfish concerning seawater was on the order of Ni>Fe>Co>Cu>Pb, regarding the food web, it was in the order of Pb>Ni>Fe>Cu>Co. The results indicated that seawater is responsible for Ni, and Fe accumulation in greater lizardfish tissues, and the food web is responsible for Pb and Ni accumulation. Depending on the mineral, metal concentrations in food or water can be used to predict metal concentrations in fish tissues.

The aim of this work is to study some biological features of the near-bottom morpho-ecological group (MEG) of Baikal omul, Coregonus migratorius, which spawns in the rivers of the Posolskiy Sor Bay. The fish were collected using nets set from the Posolskiy Sor Bay, Lake Baikal in the first half of September 2019-2020. A total of 116 spawners, including 54 females and 62 males were collected. During the study, the morphology and fecundity of the reproductive gild of Baikal omul in the deep-sea MEG was studied. The results showed an increase in weight indices and absolute individual fecundity. A significant increase in the length and weight of the fish were observed showing that fecundity increases with age. There were increases in average weight, total length, most body height, and absolute individual fecundity (AIF) from those reported before.

The Spanner barb, Barbodes lateristriga , a Cyprinid, lives as a benthopelagic in the clear mountain streams with rocks and boulders beds, frequently found below waterfalls. This species was previously recorded from Southern Thailand; Malay Peninsula, Singapore and Borneo. In this study, we report from Bangka Island, Indonesia. The Bangka Islands are located on the Sundaland, which has a quite high biodiversity. The specimens of B. lateristriga were taken from the Menumbing Hill River, Bangka Island, Indonesia and then identified morphologically and molecularly. The molecular identification was carried out using the DNA barcoding method and the standardized cytochrome c oxidase subunit I (COI) gene. The results of molecular analysis revealed that specimens of the Bangka Islands are B. lateristriga with a similarity level of up to 100%. This is also confirmed by the results of phylogenetic tree analysis where samples from the Bangka Islands clustered in the same group as B. lateristriga found in the Genbank.

Siamese fighting fish (Betta splendens) is originated from Southeast Asia and one of Indonesia’s most profitable exports commodity. However, scientific studies on Siamese fighting fish chromosomes remain limited. Chromosomal information is very useful for disclosing the diversity and genetic relationships of animals and provides clues to the most appropriate conservation measures for a species. Moreover, affordable chromosome visualization procedures are also a main concern for animal research. This research aims to determine the optimal chromosome preparation time, the best method for observing prometaphase, and the chromosomal characteristics of different types of betta fish based on their diploid numbers. The results showed that the optimal time for chromosome preparation is between 07:00 am and 12:00 pm and that the best method for observing chromosomes is the splash method from Kligerman and Bloom modified by soaking samples in colchicine for 11-12 h. The chromosome numbers of Giant, Plakat, Crown tail, and Halfmoon bettas are identical, i.e., 2n=42.

A six-week trial was conducted to determine the effects of Tenebrio molitor larvae meal (TM) on growth performance and body composition of Asian seabass. A total of 240 Juvenile fish (whole body weight 35.42±0.12g) were randomly distributed into four groups with three replicates (tank capacity 300l) with a density of 20 fish per replicate in a recirculating system. Fish were fed with four diets including 0%, 20%, 40% and 60% of TM substitution. At the end of the experiment, there was no significant difference in growth performance and protein efficiency ratio (P>0.05). However, the condition factor and viscerosomatic index showed significant differences among the treatments (P<0.05). Chemical analysis of fish carcasses showed significant differences in moisture and ash among the treatments (P<0.05). There was no significant difference in moisture, ash and crude protein of the hepatopancreas (P>0.05). Nevertheless, the body lipid content increased gradually as the concentration of TM in the fed groups increased. Since there were no adverse effects on growth performance when using TM meal, therefore, it can be adopted as an alternative source of protein in the Asian sea bass diets.

This study was conducted to investigate the feasibility of using poultry waste as feed powder in the common carp diet. For this purpose, the poultry waste powder was mixed with 2.5 and 3.5% of enzymes of papain, phytase, and pepsin, and their effects on the digestion and growth parameters of the fish were investigated. A total of 84 fish were divided into 14, 250L tanks at a density of 1.52g/l or 6 fish, with two replicates per treatment. Based on the results, the highest weight gain was found in T6 (99.17g), and the lowest rates in T2 (74.17g). T3 had a 57.02% increase in relative growth, T5 showed specific growth of 0.29g/day, and T4 had a decrease in food conversion efficiency (276.9%). The results revealed that enzymes improve metabolism, fish’s utilization of diets, and increase growth rates and weight gain.