Length-based fishery status of skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758) (Teleostei: Scombridae: Scombrinae) in the northern waters of the Oman Sea (Iran)

In the present study, population characteristics of Katsuwonus pelamis were evaluated by sampling fish at five fish landing sites in the northern Oman Sea (Iran) including Beris, Ramin, Pozm, Konarak and Jask from March 2017 to March 2018. The biometric analysis was performed on more than eleven thousand fish. Growth and mortality indices were calculated including infinite length (L∞=88cm), growth coefficient (K=0.3 (yr^-1)), growth performance index (Ф=4.19), natural mortality (M= 0.58(yr^-1)), fishing mortality (F=0.3 (yr^-1)), total mortality (Z=0.88±0.1 (yr^-1)) and exploitation coefficient (E = 0.34 (yr^-1)) as well as length time at time zero (-0.41). Relative production per recruitment, relative biomass per recruitment and exploitation rate of K. pelamis were Y /Rp=0.01, B /Rp=0.4 and U=0.22, respectively. The present study showed that the K. pelamis had desirable stock conditions and fish stocks have not reached overfished status. The Pobj value is 1 Pobj˂2, and Popt and Pmega 0, the fishery show considered medium desirable. According to the terms and situation mentioned conditions assessed, and considering the sustainable fishing requirements, it is possible to increase the catch of this species in the south of the country.