Seasonal Productivity of Purse Seine Fisheries for Short Mackerel in Jepara Waters, Indonesia: Implications for Fisheries Logistics Planning

Abstract

The capture fisheries sector is a strategic priority in Indonesia, including Jepara Regency (northern Java), where small-scale fishers rely on economically important commodities such as short mackerel (Rastrelliger spp.). Limited systematic information on seasonal dynamics is available. This study analyzed production trends, fishing effort (monthly trips), and seasonal patterns of short mackerel in Jepara waters to support sustainable fisheries logistics planning. Secondary monthly landing data from the Ujungbatu Fish Landing Site (2020–2024) were used, with effort defined as the total number of mini purse seine trips per month. Catch per unit effort (CPUE) and the fishing season index (FSI) were calculated using a simple moving average (SMA). The results showed highly fluctuating monthly production, a gradual decline in fishing effort during 2022–2024, and fluctuating CPUE (highest 238.38 kg/trip in July 2024 and lowest 7.84 kg/trip in December 2020). FSI analysis identified March to July as the productive fishing season, with a peak in July, while January to February and August to December were mostly non-seasonal. The findings indicate that CPUE dynamics are influenced not only by fish stocks but also by socioeconomic and logistical factors, including labor constraints and operational costs. Seasonal information provides a scientific basis for adjusting fishing effort and planning logistics to stabilize supply and support sustainable short mackerel fisheries in Jepara, Indonesia.