Growth, mortality, and exploitation rate of spadenose shark (Scoliodon laticaudus) landed at PPI Dumai, Riau Province

Faculty of Fisheries and Marine Science, Universitas Riau, Pekanbaru, Indonesia 28293

^* Corresponding author: rinasibagariang@lecturer.unri.ac.id

Abstract

The IUCN Red List most recently evaluated the spadenose shark (Scoliodon laticaudus) in 2005 and classed it as near threatened. The research was done at fish landing locations at PPI Dumai between May and July 2023. The goal of this study is estimating spadenose shark growth, mortality, and exploitation rates. Total length and total weight were the kind of information that were collected. The frequency distribution formula was used to assess the frequency of fish length. The FISAT II program’s ELEFAN 1 was used to examine fish growth parameters. The result showed that there were 1103 fishes (590 females and 513 males) captured. The total length (TL) of spadenose sharks in May, June, and July respectively obtained the range between 251-470; 218-500, and 279-485 mmTL with a maximum length of 500 mmTL. With an assumed coefficient of determination (R²) of 0,68, the relationship between total weight (in g) and total length (in mm) for the combined sexes is estimated as W = 0,0001TL^2,4582. The growth pattern of spadenose shark is negative allometric. Asymptotic length (L∞) = 578,2 TL, growth rate (K) = 0,51 y^-1, and theoretical age at length 0 (t₀) = -0,86 y were found as estimates of the growth parameters. Total mortality (Z) was 2,24 y^-1, with natural mortality (M) at 0,52 y^-1 and fishing mortality (F) at 1,72 y^-1. The exploitation rate (E) for this fish was 0,77y^-1, which indicates high levels of exploitation.