Length-weight relationships of five needlefish species from Kerala waters, south-west coast of India

Abstract

Summary Length‐weight relationships (LWRs) were estimated for five needlefish species such as Ablennes hians (Valenciennes, 1846), Tylosurus crocodilus (Péron & Lesueur, 1821), Tylosurus acus melanotus (Bleeker, 1850), Strongylura leiura (Bleeker, 1850), and Strongylura strongylura (van Hasselt, 1823). Specimens were collected on weekly basis from Cochin Fisheries Harbour (Lat. 09056′327″N, Long. 76015′764″E), Munambam Fisheries Harbour (Lat. 10010′965″N, Long. 76010′258″E), Kalamukku (Lat. 09059′924″N, Long. 76014′564″E) and Chellanam (Lat. 09047′950″N, Long. 76016′551″E), between October 2015 to August 2017. Fish were captured by traditional long liner (hook no. IX‐XIV) and ring seiner (mesh size 8–24 mm). The estimated allometric co‐efficient b values ranged from 3.063 (Tylosurus acus melanotus) to 3.962 (Strongylura leiura) and r2 values ranged from 0.850 (Tylosurus acus melanotus) to 0.992 (Tylosurus crocodilus). All the LWRs were highly significant, with p < .001. In addition, the study provides the first estimate of LWR for Tylosurus acus melanotus and new estimate for other four species of needlefish.

Length-weight analysis of three needlefish species from the Lakshadweep archipelago

“…In the present study, the calculated allometric coefficient b values were well within the recommended values of 2.5–3.5 (Froese, ). Our LWR b values are comparable to those of Kasim, Hamsa, Rajapackiam, and Balasubramanian () from the South‐east coast of India, Roul et al () from South‐west coast of India and Sabrah, Amin, and Attia () from the Suez Canal. Though Roul et al, () and our study procured samples of needlefishes from the same geographical region (i.e.…”

“…Our LWR b values are comparable to those of Kasim, Hamsa, Rajapackiam, and Balasubramanian () from the South‐east coast of India, Roul et al () from South‐west coast of India and Sabrah, Amin, and Attia () from the Suez Canal. Though Roul et al, () and our study procured samples of needlefishes from the same geographical region (i.e. Arabian Sea), differences in b values for T. crocodilus from the Lakshadweep island compared to those from mainland India could be attributed to the difference in the fishing gear employed, and the occurrence of larger‐sized individuals with greater body mass within the samples.…”

“…The length‐weight relationship described by the equation W = a TL b , where W is the total weight (g), TL is the total length (cm), a is the intercept related to body form and b is the regression coefficient (Froese, ) was estimated, together with the parameters a , b and r 2 (coefficient of determination) using least‐square regression analysis of the logarithm‐transformed LWR expression log W = log a + b log TL (Garcia, ). Normalization of the data was carried out using log‐log plot of the length‐weight pairs and the 95% confidence limits (Cl) of a , b and r 2 were estimated (Froese, ; Roul et al, ). Statistical analysis was carried out using Excel 2010 for Windows.…”

Length–weight analysis of ten species (Actinopterygii) supporting subsistence fishery in Lakshadweep waters, southern Arabian Sea

“…The LWR b values calculated for all the tuna species in the presently reported study were slightly lower than those from the earlier reports (Stequert et al 1996;Khan 2004;Ghosh et al 2010Ghosh et al , 2012Koya et al 2012;Mariasingarayan et al 2018). A similar trend was observed for all the needlefishes; wherein, the b values were significantly lower compared to earlier reports of Roul et al (2017) and Shahul Hameed et al (2018). For the remaining fish species, the b value was significantly higher than those already reported (Milton et al 1991;Nasser 1999;Tabassum et al 2015).…”

“…log W = loga + blogTL Normalization of the data was carried out using loglog plot of the length-weight pairs, and the 95% confidence limits (Cl) of a, b, and r 2 were estimated (Froese 2006;Roul et al 2017). The null hypothesis that b = 3 (i.e., individuals show isometric growth pattern; Froese 2006) was tested using two-tailed t-tests.…”