Trammel net size-selectivity for Hipposcarus harid (Forsskål, 1775) and Lethrinus harak (Forsskål, 1775) in coral reef fisheries of Jeddah, Saudi Arabia

Abstract

The present study estimated the size-selectivity of Hipposcarus harid and Lethrinus harak caught in monofilament trammel nets of 50, 56, and 62 mm inner-panel mesh sizes. Fishing was carried out in the coral reef fisheries of Jeddah during the period from June 2013 to March 2014. The selectivity parameters were calculated using the SELECT method implemented in Pasgear 2 software. The normal location, normal scale, log-normal, gamma and bi-modal selectivity models were fitted to the data to estimate the selectivity curves. Results indicated that the log-normal model provided the best fit based on the lowest deviance value. Modal lengths estimated from the log-normal selectivity curves are: 19.73, 22.10, and 24.46 cm for H. harid, 18.41, 20.62, and 22.83 cm for L. harak caught with 50, 56 and 62 mm inner-panel mesh sizes, respectively. The length–girth relationship was estimated and described by the linear equation: G = 0.480 + 0.70 L (r2 = 0.95) for H. harid, and G = 0.73 L − 0.65 (r2 = 0.96) for L. harak. For proper management of H. harid and L. harak, the minimum inner-panel mesh size should be 62 mm to catch fish sizes larger than the length at maturity for both species.

Keywords

• Hipposcarus harid
• Lethrinus harak
• Selectivity models
• SELECT method
• Length–girth relationship
• Inner-panel meshes