Iranian Journal of Ichthyology
Volume:10 Issue: 1, Mar 2023

A total of 460 specimens of Planiliza abu(Heckel, 1843) were collected from the Karun River of Khuzestan Province, Iran (November 2016-September 2017).Sex ratio was 1:1.06 male to female which was not significantly different (P>0.05).The average condition factor for males and female was 1.34 and showed no significant difference among different months in both sexes (P>0.05). The total length range was 9.3-17.3cm (13.18±1.35), and the total weight 10.3-71.28g (31.05±9.22).The maximum age based on scale readings was 7+years for females and males. The most frequent age groups were 4+in both sexes. The total length-weight relation for females was W=0.03TL2.63(R2=0.88) and for males was W=0.02TL2.72(R2=0.91), indicating a negative allometric pattern for females and males. The Von Bertalanffy growth model was estimated as Lt=11.90[1-e 0.21(t-2.26)] and Lt=13.45[1-e-0.66(t-3.67)] for males and females, respectively. The growth performance index (Ф') value was 3.39 in males and 4.79 in females, indicating a faster growth rate in females.

Fish are a significant component of the aquatic environment and are crucial insupporting and maintaining the entire ecological system, thereby making freshwater systemsmore resilient and sustainable.The structure of a fish community is influenced bybiotic interactions and abiotic variables. In recent years, spanning from thelast 5 to 10 years, conservationists and commercial fishermen have reporteda significant declinein freshwater fisheries. The decline can be attributed to several factors, includingthe introduction of exotic species, construction of dams, anthropogenic activities, illegal fishing, and overfishing. Schizothorax richardsonii, is a highly valued freshwater fish, inhabiting the foothills of the Himalayan regions. The declines of S.richardsoniiin the Himalayan region are more than 90% in some areas and the predicted overall reduction is inferred to be around 50% with similar rates. Withstanding all the variations in biotic and abiotic factors, the species is expanding its range of altitude and evolving according to the climate-driven shifts in the Himalayas and apparently, its current distributional range would be lost over time. In Indo-Himalayan ranges, there is a lack of conservative measures and as a result, despiteits ecological importance, snow trout has been given a vulnerable status by IUCN 2020. This review aims to provide descriptive biology and discuss the anthropogenic impact on the population structure of snow trout and its conservation.

We listed 28 exotic fish species belonging to 22 genera, 15 families and 12 ordersfor Iranian part of the southern Caspian Sea basin, based on published records and specimens collected between 2000 and 2023. Their native distribution ranges, as well as occurrences in the Iranian waters are given, and the presence of four species is recorded for the first time from the region. Two species are new records for the whole country. The family containing the highest number of exotic species is Xenocyprididae(5 species) followed by Cyprinidae (4 species), Mugilidae and Poeciliidae (3 species each), and Salmonidae and Loricariidae(2 species each). Five species were determined to be invasive due to their wide distribution, established populations, and fast dispersal through the region (Gambusia holbrooki, Carassius gibelio, Hemiculter leucisculus, Pseudorasbora parva, and Rhinogobius cheni). Alien fishes have been introduced for a variety of reasons in the region, including ornament, sport, aquaculture, biological control, and by accident.

Copepods are vital key components of marine and freshwater ecosystems and play an important role in the transfer of energy from primary producers to secondary producers and consumers. The optimization of feeding copepods with the desired diet is essential to culture them in large quantities. Hence, this study aimed to investigate the high-density production of a marine copepod, Dioithona rigidausing different microalgal diets and evaluate the growth and survival of marine finfish larvae (Asian seabass), Lates calcarifer. The high-density culture was observed in D. rigidafed a mixed diet (50:50) of C. vulgarisand N. oculata, which reached a population density of 22500±2523 ind./L on the 21stday culture period. Essential fatty acids like Linolenic acid and Docosahexaenoic acid show significantly higher percentages in copepods fed a mixed algal diet than those fed with mono algal diet. About the larval rearing experiment of L. calcarifer, the larvae fed D. rigidaenriched with a 50:50 mixed diet of C. vulgarisand N. oculatashowed faster growth (Length 17.2±0.34mm; Weight 25.4±0.38mg) and highest survival (90%) compared to the other experimental group. This indicates mixed algal diet is more suitable for culturing the aquaculture live feeds for copepods.

Coringa Wildlife Sanctuary is one of the unique ecosystemsin the State of Andhra Pradesh which is endowed with a complex of riverine, estuarine, mangrove, coastal and marine ecosystems with an area cover of 235.70 sq. km. During the faunal surveys in the mangrove forests of thesanctuary, two species of gobiid fishes viz., Eugnathogobius kabiliaandPseudogobius fulvicauduswere identified as new distributional record from the Indian Ocean. Pseudogobiusfulvicauduswhich had morphological similarity with P.javanicuswas confirmed using molecular analysis.

In the present study a trial for induced breeding of a minor bagrid Mystus vittatus was made by stripping methods using various doses (0.2, 0.3, 0.4,0.5, 0.6 and 0.7 ml/kg body weight) of a synthetic hormone, Ovasis at 26, 28 and 30ºC to evaluate their breeding performance. During spawning their latency period ranged between 12-17h. Highest number of absolute fecundity (3785 nos.) and relative fecundity (209.04 nos./g) were recorded at the dose of 0.5 ml/kg body weight of female at 28ºC. Similarly highest breeding success was observed at this dose and temperature when female was bred with male counterpart treated with a dose of 0.2 ml/kg body weight. In this condition the rate of fertilization and hatching of eggs were 84.15% and 75.48% respectively. Lowest breeding performance was recorded at the dose of 0.7 ml/kg body weight of female at 26ºC. Further, the developmental stages of fish (fertilized egg to 28thday old fish) were also characterized chronologically along with their behavioral tendency in this study. Morphological deformities of 6.3% was recorded at 26ºC in the hatchlings developed from the eggs under the administration of dose of 0.7 ml/kgbody weight. Recommended dose of ovasis is 0.5ml/kg of Mystus vittatusat 28ºC.