Iranian Journal of Ichthyology
Volume:8 Issue: 1, Mar 2021

The reproductive biology of Indian halibut, Psettodes erumei, a commercially valuable flatfish species, in the northern Persian Gulf and Oman Sea was studied. A total of 433 specimens were collected monthly from October 2016 to November 2017, and their length, weight, sex, gonad and liver weight, and maturity status were recorded. Monthly variations in Gonado-somatic index showed two obvious peaks in the spawning period in both sexes. Observations from the seasonal maturation curve, the frequency distribution of the female gonadal development stages and the condition factor confirmed recent findings that the spawning periods have two peaks, a higher peak in April-May (spring) and a lower peak in October (autumn). The size at first maturity of females was estimated to be 38.20 cm in total length. The absolute fecundity ranged from 18072 to 332171 eggs while the relative fecundity ranged from 22 to 161 eggs/g. Absolute fecundity was positively correlated with body related parameters (total length/weight) and with gonad weight. Combined, the information provided in this study could be useful for resource managers to set seasonal closure during peak spawning periods and implement minimum size limits above the size at first maturity to let the fish spawn at least once before capture.

The diploid chromosome number and chromosome morphologies of endemic Oxynoemacheilus simavicus (Balık & Bănărescu, 1978) were revealed out from Gediz River, Turkey. Metaphase chromosomes were obtained from head kidney cells. The diploid chromosome number was found as 50 and karyotype was consisted 13 pairs of biarmed and 12 pairs of uniarmed chromosomes. Fundamental arm number was calculated as 76. The obtained results shall contribute to nemacheilid chromosomal studies.

The Snakeskin gourami (Trichogaster pectoralis) from Sungai Batang swamp, Indonesia has high commercial value and high pressure on population due to fishing, while the fish growth condition is poorly studied. A total of 848 fish ranging 75-200mm (119.14±18.43mm) (TL) and 5-132g (29.76±14.76g) were sampled to estimate its lengthweight relationship and condition factors. Local fishermen mostly collected them using horizontal gill-net and also electrofishing device. Based on the results, the Snakeskin gourami grow allometrically (b=2.7748-2.8971), indicating that fish becomes slender as the length increases. Total length and weight of female were significantly higher than those of male (P<0.001). More than 21% of total catch was in 105-114 mm TL, and more than 34% existed 15-24g weight classes. No difference was observed in the percentage of catch number between male and female, as well as in condition factor (K) (P>0.05). The mean K values for male and female were 1.64±0.24 and 1.66±0.21, respectively, indicating that fish in the swamp is in good condition.

The cultured and wild specimens of the Nile tilapia (Oreochromis niloticus) are often infected by different hazardous as helminths; protozoa and arthropod which cause various degrees of diseases in such fish. The aim of this study was to record the most common protozoan parasites in the Nile tilapia in Egypt, and also assessment of the immunological changes through analyzing two genes (Tumor Necrosis Factor alpha, TNF-α; and Interlukin1β, IL- 1β) in the infected fishes using qRT-PCR. Therefore, each fish individual was examined carefully, and smears were prepared from each organ; stained with Giemsa dye and examined under a light microscope. qRT-PCR was performed on infected tissues (skin and gills) by various collected parasites. Four trichodinid species (Trichodinella heterodentata, T. centrostrigeata, T. epizootica, Paratrichodina Africana,) were isolated and identified; also two Myxobolus spp. (M. tilapiae and M. heterosporous) were fully described. In skin, TNF-α in M. tilapiae and mixed groups were nearly similar and were significantly higher than Trichodina spp. group. IL-1β of M. tilapiae group was significantly lower than that of the mixed group; Trichodina spp. and control groups. In gills, TNF-α of the mixed group showed the significantly highest value. IL-1β was nearly same in all groups. We conclude that the skin is nearly higher in upregulation of the two studied genes comparing to the gills analysis, since it is considered as the first barrier in fish and contains many immunological defined cells.

Homaloptera gymnogaster (Family: Balitoridae) is an endemic freshwater fish in Sumatra, Indonesia that can be found up until a high elevational aquatic body. There is no previous report about a thorough study on its morphological variations from its various populations. In this study, 47 individuals H. gymnogaster were collected using random sampling from five different elevations (Sikai River at 1996, 1552, 1420, Batang Gumanti on 1531, and Matur River on 1097 m asl), on which 53 morphological characters measured. The result indicated that 41 characters significantly varied with the Kruskal-Wallis test (P<0.05%), which consist of 29 morphometric and 12 meristic characters. The MannWhitney U test (with <0.05% standard confidence) confirmed the high differentiation on morphometric and meristic characters among the study sites. The Principal Component Analysis (PCA) plot hinted that albeit populations in Sikai River divided come from different elevations, were still categorized as the same group. On the contrary, Batang Gumanti and Matur River site separated into different groups. This study concluded that differentiation of morphological characters on H. gymnogaster was influenced by current velocity and river size.

The Stinging catfish, Heteropneustes fossilis (Bloch, 1974) is a commercially important fish species in Asia. This study describes some biological aspects of H. fossilis using a total of 250 individuals which were captured during July 2017 to June 2018 by various types of traditional fishing gears and measured biometric data for each individual The recorded results showed that the TL was varied from 10.30 to 20.50cm and BW was ranged from 4.42 to 50.91g. All LWRs were significant (P<0.001), with r2 values ≥0.952. The calculated allometric coefficient (b)showed positive allometric growth in ombined sexes (b>3). The LLR was significant (P<0.001) with r2 value > 0.988. The a3.0, Lm, and MW were 0.0063, 12.09cm TL and 1.09y-1 for H. fossilis in the Gajner Beel, respectively. These findings would be very effective for further stock assessment and management of this fishery in the Gajner Beel wetland and adjoining ecosystems.

Length weight relationships (LWRs) were estimated for five endemic/native fish species collected from five localities in the inland waters of Oman in 2020 including Aphaniops kruppi and A. stoliczkanus (Aphaniidae), Cyprinion muscatense (Cyprinidae: Barbinae), and Garra barreimiae and G. longipinnis (Cyprinidae: Labeoninae) using foldable shrimp and crab fishing traps (mesh size of 3*3mm) and scoop nets (mesh size of 3*3mm). The parameter of b for all five species was within the expected range of 2.5–3.5. as proposed for different fishes (except for female A. stoliczkanus), and there were high and significant correlation coefficients for all species (0.931-0.972). Bailey’s ‘t’ test in the five studied species showed that b value significantly deviated from 3.

The Turkestan barbel, Luciobarbus conocephalus (Kessler, 1872), is documented from the Iranian Part of Hari River basin by providing its morphometric and molecular characteristics based on the nine collected specimens in July 2016. In addition, the ichthyofauna of the Hari river basin was discussed and an up-to-date inventory was provided. Based on the results, L. conocephalus was clustered in a clade as sister group of L. capito with K2P genetic distance of 1.8% in the mtDNA cytb region. Luciobarbus conocephalus probably has entered the Hari River from the Karakum Canal in Turkmenistan (diversion from the Amu Darya River) that in recent years was connected to the channels collecting the Hari River water. Also, a misidentified specimen of L. conocephalus sequence in the GenBank sequences is discussed.