Composition of catch results according to moon phase on purse seine vessels in Belawan waters, North Sumatera, Indonesia

Purse seine is one of the dominant fishing gears in the waters of Belawan, North Sumatra, Indonesia. Fishing activities can run well if fishermen know the factors that influence fishing success. The lunar day period can indicate a good time for fishing operations because there are changes in light intensity during each lunar day period and will affect fish that have positive or negative phototactic properties towards light. Differences in intensity will affect the volume of catch when fishermen operate. Research activities will be carried out from November 2022 to March 2023, taking part in fishing operations with purse seiners in Belawan, North Sumatra. This research aims to determine the composition and quantity of catches, determine the factors causing the diversity of catches in the lunar day period, and determine the amount of catch production in the lunar day period. The composition of the catch according to the moon phase is dominated by the new moon at 5,900 kg (40%), the first semi-bright moon phase (quadrant I) 4,215 kg (30%), the second semi-bright moon (quadrant II) 3,250 kg (17%), and at Full Moon Phase 3,465 Kg (13%). In the New Moon Phase period, it is a lunar phase that is very effective for the fishing process, because the catch obtained is the largest catch compared to other lunar phases, whereas in the Bright Moon Phase the catch is not very effective because the catch is less than optimal, which affects selling value. The lunar day period factor will indirectly impact the availability of fish resources, so fishermen need to know changes to the lunar day period system.