─The declining trend of Yellowfin Tuna Thunnus albacares production in Fishery Management Territory of Indonesia 714 nowadays will affect the demand for tuna products in Indonesia and global. Regarding the management purposes, the impact of fishing needs to be minimized. Therefore, the estimation of population structure based on the length and age is very important to be studied. The data were collected from November 2015 to October 2016 from longline and handline catching activities operated in the Banda Sea. The average length of yellowfin tuna caught with longline and handline was 98.5 cm and the first length maturity was Lm 103.6 cm. The result showed that the first yellowfin tuna caught was Lc_opt 125.2 cm, where fishing mortality ratio toward natural mortality was at the level that endangered the sustainability of yellowfin tuna fisheries in the Banda Sea . To minimize the impact, there needs to be a minimum size regulation of yellowfin tuna that should be landed.

The existence of mackerel scad in Ambon waters, Moluccas Indonesia has decreased from year to year mainly due to the over exploitation. This research aimed to study the biological aspects, in particular were sex ratio, age group and length at first maturity of mackerel scad (Decapterus macarellus) from this area. Sampling was done on September 2016 to July 2017 at the southern waters of Ambon Island. Samples collected were dissected to determine their sex and their gonad maturity level then measured. Bhattacharya method was used to determine age group while Spearman- Kaber method was used to identify length at the first maturity of this species. It was found that mackerel scad in the southern waters of Ambon Island had an equal number of male and female that consists of four age groups with length at first maturity for male and female were 24.9 cm and 24.8 cm, respectively.

Marine fish supply chain is an integrated process that combines production until shipping, as well efforts to cut coasts through shipping so as to provide consumers with good service. Eri’s fish landing center is one of the contributors to the stock availability of layang fish in the Ambon. The purpose of the research is to analyze the supply chain layang fish and the level of efficiency. Data were collected by purposive sampling with primary and secondary data from September-December 2019. The results of the study obtained three supply chains with four actors involved in it. Strategies to reduce margins and shorren supply chains by involving key players at high prices, namely papalele and the government at low prices, It is hoped that this alternative is one of the supporting the national fish barn.

─Mackerel scad (Decapterusmacarellus) is one of the small pelagic fish that has important economic value and caught throughout the year around the waters of Ambon. Utilization of these fish is not only profitable economically but also can have a negative impact if not pay attention to aspects of sustainability. The purpose of this research is to know the distribution of long frequency and growth pattern. This research was conducted for six months (September 2016-February 2017 around Ambon waters. Samples of fish analyzed amounted to 1548 individuals. The average length of the minimum fish caught is 9.5 cm and the average size of the maximum length of fish caught is 31.8 cm. Fish growth patterns obtained are isometric.

Various fishing gears that are operated in the coral reef waters of Western Seram Regency have their own selectivity, capture various species of fish, and have an impact on the damage to coral reef ecosystems. This study aims to determine the leading reef fishing gears in Western Seram District. The survey method is through observations and interviews with fishermen who conduct fishing activities of coral species. Respondents are determined by propulsive sampling, the selection of superior fishing gear is done by the scoring method. The results showed that the fishing gear classified into the line fishing gear was superior to other fishing gear, where the bottom trolling were superior. The less favored coral fishing equipment especially from the biological aspect needs attention to improve the method and design of the fishing gear.