Sex ratio and first maturity of blackeye thicklip wrasse Hemigymnus melapterus Bloch, 1791 in Spermonde Archipelago

Abstract

Abstract Blackeye thicklip wrasse Hemigymnus melapterus is a Labridae that was widespread throughout the tropical and subtropical waters of Indo-Pacific. In eastern Indonesia, blackeye thicklip wrasse found from the Strait of Bali, Mentawai Islands, Raja Ampat Islands, Manado and surrounding areas, and Banggai; while in central Indonesia, blackeye thicklip wrasse found in the waters of the Spermonde Archipelago. This research aims to analyze the sex ratio, gonad maturity stage, and the size at first maturity of blackeye thicklip wrasse in the Spermonde Archipelago. This research was done on the population of blackeye thicklip wrasse in the Spermonde Archipelago, South Sulawesi, Indonesia. Samples were collected from fishermen caught landed in the Rajawali Makassar Fisheries Port at Makassar City. Blackeye thicklip wrasse sex ratio was not balanced. This imbalance was thought to have something to do with the “r” reproductive strategy where blackeye thicklip wrasse tries to produce as many eggs as possible to maintain its population. The success of this strategy probably supported by protogyny reproduction patterns where young fish can produce eggs as fast and as much as possible before being devoured by predators. Based on its gonad structure, blackeye thicklip wrasse could be classified as fish with a total spawning pattern that take place long spawning period or individual different spawning period throughout the year. The size at the first maturity of blackeye thicklip wrasse female was 21.4 cm; it was much smaller than half the size that has ever been caught.