Estimating some population parameters and stock assessment of Dark Sleeper Odontobutis potamophila in the Gaosha River, Wuyuan County, Jiangxi Province, China

Abstract

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Odontobutis potamophila collected in the Gaosha river fish landing site, west part of Wuyuan County (Latitude: 29° 14' 29" N, Longitude: 117° 45' 49" E). O.potamophila were collected from November, 2013 to October, 2014. Growth parameters, asymptotic length (L ) = 192mm and growth coefficient (k) = 0.22 year -1 . Growth performance index(Ø') =3.91, total mortality (Z) = 0.72 year -1 , natural mortality (M) = 0.32 year -1 , fishing mortality (F) = 0.40 year -1 and exploitation rate (E) = 0.55year -1 .The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was sustainable exploitation in the study area. The exploitation ratios were computed as E max = 0.61, E 10 = 0.52, E 50 = 0.34. The length at first capture at 50%, (L c ) was 77 mm. The recruitment pattern of the species was found continuous all-round the year with one peak. The observation of the annual recruitment of O.potamophila found to occur from May to July. Steady biomass also increased with length class until 121-125 mm, and the total steady state biomass was found to be 2240 kg.

Population dynamics of the green tiger prawn, Penaeus semisulcatus de Haan, 1844 in the Saudi coast of the Arabian Gulf

“…This indicates that females of the green tiger prawn are more exposed to commercial catch because of their bigger size compared to males. This observation is concordant with those of Hosny (2007) (Benzer, 2013), dark sleeper (Haihua & Yanping, 2018) and sergestid shrimp Amin, et al (2009) which is in accordance with our findings ( Fig 3). Table 1 summarizes most of the biological parameters of P. semisulcatus reported so far from the Arabian Gulf and some adjacent areas.…”

Estimating some population parameters and stock assesment of spiny butterfly ray, Gymnura altavela (Linnaeus, 1758) the Levant Basin coast (Northeastern Mediterranean)

“…The TL-W and DW-W relationships were determined according to the equation given by Sparre and Venema (1992), Where W = a*TL b and W= a*DW b , respectively. In the age determination, the Electronic Length Frequency Analyzes (ELEFAN) method was applied to indirect age determination methods (Hemida et al 2016;Haihua and Yanping et al 2017). In the application of lengthfrequency analysis and other specified equations, the package program FAO-ICLARM Stock Assessment Tools (FISAT I), which includes the ELEFAN program, was used (Gayanilo et al 1995).…”