Document Type : Research Paper
Authors
1
Department of Fisheries, Faculty of Natural Resources, University of Guilan, P.O. Box 1144, Sowmehsara, Iran
2
Fisheries Department, Faculty of Natural Resources, University of Guilan, P.O. Box 1144, Sowmehsara, Iran
3
2- Shahid Motahary Cold-water Fishes Genetic and Breeding Research Center, Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Yasouj, Iran
10.22124/cjes.2024.8001
Abstract
Caspian kutum (Rutilus frisii) is the most common species of the Cyprinidea family in the Iranian coastal waters of the Caspian Sea and comprises, on average, more than 70% of the annual commercial bony fish catch. This species consists of two migratory forms, the spring race (SR) and autumn race (AR), which show morphological identities. The morphological differences are classified as phenotypic markers and cannot be a reliable method for distinguishing individual and populations. Therefore, we performed histological analysis concerning ovarians, as well as gene expression profiling differences, to gain more knowledge about the differential migratory behavior of the races. Ovary and liver samples were collected to observe the reproductive performance based on the ovarian histology and related gene expression using real-time quantitative polymerase chain reaction (qRT-PCR). Histological study of the AR and the SR broods showed that the ovaries were at vitellogenic (oocyte diameter is 978.4 ± 32.3 µm) and maturation (oocyte diameter is 1225 ± 27.6 µm) stages, respectively. The steps identified were predictable because the AR broods need a hibernate after migration for spawning, and the SR broods are usually ready for spawning after moving into the spawning grounds. Additionally, we performed qRT-PCR to confirm the genes involved in the vitellogenic and maturation stages of ovarian development in R. frisii. Given the lack of information about the population aspects of this species, histological and gene profiling analyses in the current study showed evidence of different migratory behaviors in the two races. These valuable results can be used in fishery management programs.
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