The Fishing Grounds and the Exploitation Status of Kawakawa (Euthynnus affinis) in Java Sea, Indonesia

Abstract

Kawakawa (Euthynnus affinis) is one of the highly favored mackerel tunas caught in Java Sea. The increase in demand due to local consumption and export eventually increases fishing that is proportional to the exploitation status. To maintain the fish resource, a scientific study should be carried out on the fishing grounds and the exploitation status of kawakawa. This study was carried out for 3 years, i.e. in March to October 2017, June to December 2018, and February to November 2019 at Pekalongan National Fishing Port in Pekalongan, Central Java, with 9,511 fish as the study objects. The data analysis was carried out by observing the fishing grounds using GPS and through interview. In addition, the exploitation status was analyzed using FISAT II application and ELEFAN program. The fishing grounds were mostly coastal waters with 15–55 cm sized kawakawa. The size of the first caught (Lc) of the kawakawa in this area ranged from 26.9 cm to 38.4 cm. The fish recruitment occurred all year long, peaking in Apr at 15.97% and Juli 13.62%.The fish natural mortality (M) was smaller than its fishing mortality (F), while its exploitation status was 0.66 (overfished), meaning that the current fishing efforts should be reduced by 32%. The other management efforts that can be carried out are among others conservation, keeping the fishing grounds outside the spawning grounds, and controlling the mesh size.

Estimating relative abundance of kawakawa (Euthynnus affinis Cantor, 1849) landed in eastern indian ocean using catch and effort data

“…In this study, the size distribution of kawakawa ranged from 16 to 77 cm FL. The result aligned with the previous studies in the Western Sumatera, Java Sea, Persian Gulf, Sea of Oman, and eastern Mediterranean coast [6,14,16,18]. Most of the lengths of kawakawa landed in the Eastern Indian Ocean in the present study were above the length at first maturity (>38 cm FL).…”

“…Catch proportion for kawakawa from the two species, i.e., frigate and bullet tuna, is essential in fisheries science. These two species are at the same school with kawakawa in the water [14]. Thus, these three species were mainly caught together when the fishers deployed the fishing gears.…”

Population dynamics and stock status of spotted sardinella (Amblygaster sirm, Walbaum, 1792) in the Natuna Sea, Indonesia

“…Spotted sardinella has a length of 12.3 to 24 cm (to-tal length) in the Red Sea off the coast of Egypt (Osman et al, 2021). The length frequency might vary between regions due to the availability of prey, environment, fishing ground, and fishing season (Mardlijah et al, 2022). Furthermore, the length-weight relationship indicates the growth pattern of fish (Ragheb, 2023).…”

“…However, in general, the spawning state of spotted sardinella is partial (partial spawning) based on variations in the gonad maturity index according to the size and level of gonad maturity (Widiyastuti & Zamroni, 2017). The Lc 50 and the Lm 50 are related to the same fish sample measured, fishing area, mesh size, and growth of male and female fish caught (Mardlijah et al, 2022). Therefore, this should be a concern so that the fish caught are above 17 cm and are closely related to the mesh size used in purse seine gear.…”

Population genetic structure of Kawakawa (Euthynnus affinis Cantor, 1849) in Malaysian waters based on COI gene

“…Kawakawa, scientifically known as Euthynnus affinis (Cantor, 1849), is a type of tuna found in the Indo-Pacific region, particularly in warm seas. It is a crucial species for Malaysia and nearby waters but faces threats from overfishing and illegal fishing activities (Samsudin et al 2015;Mardlijah et al 2022). To ensure its sustainable use, strong surveillance and management strategies are essential.…”