Analysis of Spatial and Temporal Composition and Sex Ratio of Decapod Crustaceans Catch from Southeast Sulawesi Waters of Indonesia

Abstract

The spatial and temporal decapod crustacean (DC) catch composition (CC) and its sex ratio (SR) taken from Tiworo strait were studied. Monthly samples from different habitat characteristics of intertidal zone (station A), river mouth (station B), sea grass (station C), and water depth of > 30 m (station D) using collapsible crab pots and gillnets were recorded, identified its species, sexed, counted its number, and analyzed its spatial and temporal CC and SR. The Chi-square test (α = 0.05) was used to test significant differences of expected 1: 1 SR. It was 12 DC species had been identified which BSCs were found at the entire stations and all years round. It had high CC at each station ranging 21.561–79.176% which was found the highest at station A, while CC in each month ranging 43.023–71.898% which was mostly found in March and April. Its CC reached 60.589% of total catch. The CC of other dominant species of C. anisodon, C. hellerii, and T. crenata had 5.721–50.186%, 0.458–1.550%, and 1.931–10.781%, respectively, while the rest species had CC of <3%. Spatial and temporal SR of females BSCs always preponderated over males, while C. anisodon, T. crenata, and T. danae were in contrary. Similar results were also showed for overall sex ratio of each species. The other species were mostly no patterns of SR. Chi-square test showed that those SRs were mainly significant different (P < 0.05). Data of CC implies that this waters constitutes main habitat for BSCs which prefer intertidal zone grown by mangroves (station A) particularly in March and April. Other species such as C. anisodon, T. crenata, and T. danae as bycatch which relatively low their CC may show that their population had been experiencing heavy pressure. Therefore, an action reducing bycatch should be implemented through for example providing fishing gears selective. The present BSC SR should be put in management policy in order to maintaining female adults are available all years round to produce eggs, hatch and grow to be juveniles. Therefore, BSC population stocks in this waters are continuously sustained.