Conservation for production? The benefits of mangroves for sustainable shrimp aquaculture

Background

Increasing shrimp demand and declining annual shrimp harvests threaten mangroves in East Kalimantan, Indonesia, due to deforestation from shrimp aquaculture expansion. Silvofishery practices that combine shrimp aquaculture with mangrove conservation are promoted to prevent further mangrove deforestation while still protecting the shrimp farming industry. Mangrove ecosystem services are essential for aquaculture systems to thrive, so it is important to determine successful biophysical elements of silvofishery systems to encourage the development of more sustainable aquaculture practices.

Goals and Methods

This study aims to assess the effects of different production (i.e., labor, shrimp fry, pond size) and biophysical (i.e., adjacent mangrove buffers, mangroves inside pond) factors on shrimp aquaculture in Berau, East Kalimantan Province, Indonesia. The authors collected survey data in 2023 from 811 pond owners or managers (over 85% of the pond owner population) about production factors, aquaculture inputs, management data, and annual and cyclical shrimp production. They combined this data with a GIS analysis of the proximity of mangroves to the nearest salty, brackish, and freshwater bodies using 2019 satellite imagery. The authors developed a mathematical model to predict shrimp production in traditional aquaculture ponds and a simulation of different mangrove reforestation and deforestation scenarios.

Conclusions and Takeaways

This study finds that high-density mangroves surrounding aquaculture ponds will increase shrimp production. The shrimp production model indicates that increasing the area of high-density mangroves bordering ponds by 1% within a 100 m buffer increases shrimp production by 0.25%. Reforestation simulation results show that restoring all areas bordering existing aquaculture ponds within a 100 m buffer to high-density mangroves would increase total shrimp production by about 19% and sequester 43% more carbon than the current aboveground biomass in the buffer zone. Additionally, only low-density mangroves inside aquaculture ponds increase shrimp production. These results indicate that silvofishery systems that spatially separate high-density mangroves and aquaculture ponds (i.e., 80% of the area contains restored mangroves, while 20% of the area is for intensified shrimp aquaculture) maximize the ecological and economic objectives of integrated mangrove aquaculture.