Reproductive traits in dolphinfish Coryphaena hippurus Linnaeus, 1758 along the coastal waters of Karnataka, south-eastern Arabian Sea

Abstract

The maturity, sex ratio, gonadosomatic index (GSI) and fecundity of Coryphaena hippurus was investigated from 347 specimens collected along Karnataka coast, south-eastern Arabian Sea from August 2017 to May 2018. Overall sex ratio of 1:3.5 (male:female) indicated dominance of females in the fishery and differed significantly (p<0.05) in all the months, except in January, May and December. The fork length (FL) at 50% maturity (Lm50) was estimated at 47.5 cm for both males and females. The pattern of GSI and maturity stages suggests peak spawning activity in August-September. However, the incidence of fishes capable spawning all through the year in varied proportions implied that spawning activity occurs throughout the year. The absolute fecundity estimates varied from 1,00,298 eggs for a female of 53.5 cm FL to 6,15,267 eggs for female of 113 cm FL with an average fecundity of 3,18,446 eggs per female. Thefecundity of fish increased with body length and weight as well as with gonad weight. The biological information on maturation, reproductive cycle, spawning periodicity and fecundity of C. hippurus in the tropical Arabian Sea could be useful for developing appropriate management tools and conservation strategies for this commercially important fish species.

Understanding the fishery dynamics and stock health of mahi-mahi Coryphaena hippurus (Linnaeus, 1758) from Indian coastal waters

“…Kumar et al (2017) reported a range of 35-40 cm FL for both sexes from the Saurashtra coast of India. In contrast, Ghosh et al (2022) reported 59.9 cm for males and 54.5 cm for females, and Assana et al (2021) reported 47.5 cm FL for both sexes in the south-eastern Arabian Sea, India. The small size comprising the dominant group in the fishery and early age of maturation (L m50 ) may ensure large SSB levels for the species.…”

“…Similar studies have reported varying female sex ratios in C. hippurus from different regions around the world, such as 1:1.9 in North Carolina waters (Rose and Hassler, 1974) and 1:1.8 in the Florida current (Oxenford, 1985). In Indian waters, observations include 1:2.05 from the Southwest coast of India (Rajesh et al, 2016), 1:1.75 from the Saurashtra coast (Saroj et al, 2018), 1:2.09 from the Bay of Bengal (Ghosh et al, 2022) and 1:3.25 from the South-eastern Arabian Sea (Assana et al, 2021). These variations in sex ratios may be attributed to sexual disparities in migration, spawning, or other reproductive behaviours (Hunter and Macewicz, 1985).…”

“…However, there is a dearth of information regarding their population characteristics along the Indian coast. Previous studies have explored the fishery, diet composition and reproductive biology of C. hippurus (Linnaeus, 1758) in various regions such as the Eastern Arabian Sea (Varghese et al, 2013), Karnataka coast (Rajesh et al, 2016;Assana et al, 2021), west coast of India (Kumar et al, 2017) and Saurashtra coast (Saroj et al, 2018a). Additionally, research has been conducted on the length-weight relationship of C. hippurus and C. equiselis by Retheesh et al (2021) and Assana et al (2020); GIS-based mapping of C. hippurus along the Saurashtra coast by Saroj et al, (2018b) and the stock status of the species in Indian waters by Manjusha et al (2012) and from the Kerala coast by Benjamin and Kurup (2012).…”

First report on the diet and reproductive biology of red-toothed triggerfishOdonus niger(Ruppell, 1836) from the south-eastern Arabian Sea

“…The knowledge on the length at first maturity (L 50 ) is an essential parameter for many assessments (Assana et al, 2021). The estimated L 50 (TL) of males and females determined in this study were 178 and 180 mm, respectively.…”

“…A more pronounced sexual difference in the length at maturity was reported by Rivera et al (2019) for B. vetula from Puerto Rico (L 50 = 206 mm for males and 256 mm for females). Divergence of more energy for reproduction could be related to the longer time taken by females to mature (Rajesh et al, 2021). In contrast, the maturation of females at a smaller length than males has been recorded in B. capriscus from the south-eastern US Atlantic coast (Kelly-Stormer et al, 2017; L 50 = 184 mm for males and 177 mm for females) and Gulf of Gabes (Kacem & Neifar, 2014).…”