The dynamics of target fishes resources in coral reef fisheries at coastal area of Ternate Island

Faizal Rumagia,Mennofatria Boer,Rahmat Kurnia,Mohammad Mukhlis Kamal

doi:10.13170/depik.8.2.13358

Abstract

Abstract. As one of the coastal ecosystem, coral reef ecosystem is a magnificent marine ecosystem, where their species richness and composition play an important role for the ability of coral reef ecosystem to respond to the fishing activity and other stressors, where fishing has impacted the fish community, target or non-target reef fish species. The dynamic of reef fish resources, especially the target species, become one of the aspects that must be considered in the management and utilization of the fisheries resources in the coral reef ecosystem and their surrounding area. The purpose of the study was to analyze the dynamics of the target fish in the coral reef fishing activity at the coastal area of Ternate Island, from the growth, mortality and exploitation ratio aspect. The research was conduct from April to August 2018 in the coastal area of Ternate Island. The data sampling was growth parameters data through length and weight measurement. Total sample measure along the research time was 6245 sample (consist of seven family and 11 species). The result shows that the target fish have asymptotic length (L∞) range from 263.16–483.16 mm, with growth coefficient (K) ranging from 0.61–0.92 per year. The theoretic age at length 0 (t0) ranges from minus 0.0825–0.1669 year (equal to 30-61 day). The fishing mortality rate (F) is lower than the natural mortality rate (M), which resulting the exploitation rate (E) for the target fish mostly under 50%, which indicated that the utilization of the reef fishes in the coastal area of Ternate Island is still under-exploited.Keywords: Exploitation rate, Growth parameters, Length-weight relationship, Mortality rate, Stock assessment

Highlights

Ternate Island was the main island in Ternate City region, where surrounded by coral reefs ecosystem that spread from 1 m to 30 m depth
Mean length-at-age in combination with the length–weight relationship, maps the population dynamics, which is in numbers, to the catch, which is typically in weight
Ahmad (2009) that found the growth pattern of grouper (Epinephelus fuscoguttatus) from the family of Serranidae in Sulamadaha coast at Ternate Island, have negative allometric growth (b = 2.123), on the contrary, the results from this research have differ with the research from Sutrisna (2011) in Panggang Island Kepulauan Seribu District which found that the grouper fishes (Epinephelus fuscoguttatus) have an positive allometric growth (b = 3.14)

Summary

Introduction

Ternate Island was the main island in Ternate City region, where surrounded by coral reefs ecosystem that spread from 1 m to 30 m depth. Ternate Island has an active volcano mountain located in the center of the island, the Gamalama mountain. The coral reef fisheries were done along the coral reef ecosystem by the island fisherman. The coral reef fisheries at the Ternate island commonly using hand line, traps and gill nets, with catches dominated by jackfish, fusiliers, snappers, emperor fish, parrot fish, surgeon fish, and sweetlips fish. There is some valuable gastropod and crustacean becomes target species by the fisher. The catch for snapper and groupers in 2016 was 1.007 ton (DKP Kota Ternate, 2016)

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Conclusion