Gillnet species composition, catch per unit effort and length-weight relationship of some fishes in coral reef fisheries of Jeddah and Thuwal, Saudi Arabia

الملخص EN

Experimental fishing operations were conducted in coral reef fisheries of Jeddah and Thuwal using multifilament gillnets during the period from May 2013 to March 2014.

Species composition, catch per unit effort, and length-weight relationship of some coral reef fishes were determined.Results indicated that 43 species belonging to 16 families were identified in the catch of multifilament gillnets in Jeddah.

In Thuwal, 53 species belonging to 23 families were identified.

In Jeddah, four species: Acanthurus mata, Acanthurus sohal, Carangoides bajad, and Plectorhynchus gaterinus represented collectively more than half of all fish caught (about 55 %).The overallcatch per unit effort was found to be 74 fish (18.529 kg)/1000 m gillnet length.

The length-weight relationship could be described by the power form W = 0.012 L3.12for Acanthurus mata and W = 0.013 L2.97 for Carangoides bajad.

In Thuwal, four species: Caranx melapygus, Caranx sexifasciatus, Lethrinus lentjan and Naso elegans represented collectively 39.9 % of all fish caught.

The overall catch per unit effort was found to be 66 fish (31.352 kg)/1000 m gillnet length.The length-weight relationship could be described by the power form W = 0.0049 L3.26 for Caranx melampygus and W = 0.018 L2.93 for Lethrinus lentjan.

Negative impacts on the coral reef ecosystem in Jeddah and Thuwal can be produced due to overfishing and damage of coral reefs by gillnet fishing