Income of tiger shrimp (Penaeus monodon) and milkfish (Chanos chanos) polyculture farmers with mangrove-integrated and non-mangrove ponds in Sungai Meriam Village, Anggana District, Kutai Kartanegara Regency, East Kalimantan

Abstract

Traditional brackishwater ponds in Sungai Meriam Village, in the Mahakam Delta, are used for the polyculture of tiger shrimp (Penaeus monodon) and milkfish (Chanos chanos), and some ponds retain mangroves on a central mound. This study compared the annual net income of polyculture farmers with mangrove-integrated ponds and with non-mangrove ponds and identified the constraints they face. A survey was conducted from January 2024 to June 2025 among 50 farmers selected by purposive sampling (25 per pond type). Income was analysed as total revenue minus total cost, and the difference between groups was tested with the Mann–Whitney test because income was not normally distributed (Sig. = 0.003 and 0.000). Mean net income was Rp 186,452,028 per year for farmers with mangrove-integrated ponds and Rp 167,620,477 for those with non-mangrove ponds, a difference of Rp 18.8 million (11.2%). The difference was not statistically significant (mean ranks 28.00 and 23.00; asymptotic Sig. 2-tailed = 0.225). The higher gross revenue of mangrove-integrated ponds came almost entirely from tiger shrimp, and roughly two-thirds of that gap reflects a higher implied shrimp price rather than a larger harvest. The main constraints were dry-season salinity and temperature stress, which weakened shrimp and stunted milkfish, and burrowing belitung snails that damaged pond bottoms. Mangrove-integrated ponds were therefore at least as profitable as non-mangrove ponds in this sample, and no income penalty from retaining mangroves was detected, although the small sample limits the power to detect a modest difference.