Population Dynamics of Longtail Tuna (Thunnus tonggol) Exploited in the North Coast of Sumatera: Biological Parameters Estimates


Pi: Adrian Damora, S.Pi, M.Si, adriandamora@gmail.com
Institution: Faculty of Marine and Fisheries, Syiah Kuala University

Project Overview:
The west and north coasts of Sumatera, which have an oceanic frontage, have access to some species of tuna, including longtail tuna (Thunnus tonggol). West coast of Lampung, North Sumatera, and Aceh are three large landing sites of this species. Biological study on longtail tuna can be considered as a first stanza in understanding the population dynamics of the species. This study is focused on data from North Sumatera (Sibolga) and West Sumatera (Bungus), whereas there are not many data from Aceh. Set of one year (July 2018 to June 2019) length frequency data of the longtail tunawill be used in attempting to estimate the growth parameters as input data for the model of stock evaluation. Two research sites have been selected for data collection, they are PPS Lampulo, Banda Aceh and PPI Meulaboh, West Aceh. These two sites are considered representative as sampling sites due to routine landing of longtail tuna caught by purse seine and troll. The sampling is intended to gather the length frequency data and species composition by fishing zones and by purse seiners/trollers type. In this case, an assumption was done that catches or abundance be proportional to repartition of the fleet operating in the fishing zones. The biological observations cover the length, weight of body and gonads, and stage of maturity. Subsamples will be taken randomly from the fish holds of the seiners/trollers and immediately followed by sorting for separating the species. Special sampling will be done several times for collecting mature fishes for microscopic description purposes. Specimens will be dissected for gonads stages observation. For implementation of the sampling in the field, two enumerators will employed by the project for collecting these data under supervision of a scientific team.