Herman Yulianto

In response to the escalating demand for blue swimming crabs (BSC) and the consequential impact on their habitat and population, this study advocates for sustainable management through a holistic approach. Our comprehensive framework integrates ecological conservation, socioeconomic well-being, and governance principles, aiming to establish a policy framework for the sustainable management of BSC in the Eastern Coast of Lampung. The research emphasizes the urgent issue of overexploitation, with an exploitation rate of 0.71, requiring immediate attention to prevent stock depletion and maintain ecosystem health. Findings reveal that male BSC, measured by carapace width, typically reaches the length at first catch (Lc50) at approximately 118.69 mm, while for females, it is about 122.70 mm—indicating that BSC is often caught larger than the 10 cm legal requirement set by the Ministry of Marine and Fisheries of Indonesia. Economic analysis demonstrates the profitability of the blue swimming crab business on Lampung's east coast, with a favorable crab capture per trip (4.63) and total costs ratio (1.18). The study area, featuring an extensive mangrove forest, hosts a crucial crustacean population, contributing significantly to BSC's diet. Beyond ecological significance, mangrove conservation enhances our understanding of environmental sustainability, particularly in carbon stock contributions. Addressing sustainability challenges requires a multi-faceted approach, including precise fishing technologies, effective regulation enforcement, and improved monitoring. Collaborative efforts among government authorities, fishing communities, and conservation groups are essential for balancing economic interests with the long-term ecological health of BSC populations in the study area.

Aquaponics is a combination of aquaculture and hydroponics system. This system is expected to be able to overcome the problems of waste from aquaculture by utilizing Nitrogen (N) and Phosphorus (P) for vegetables. There are several obstacles found in aquaponics systems such as high suspended organic matter produced from the feed residue and fish metabolism. The addition of natural filters, namely freshwater mussels (Pilsbryoconcha exilis) is expected to solve these problems. This research was conducted for 40 days. The design used in this study was Factorial Completely Randomized Design with two main factors namely mussels density as factor-A and time of observation as factor-B. The treatments were P1 (0 mussels density), P2 (15 mussels density), and P3 (30 mussels density) for factor-A while time of observation were factor-B (D-0, D-10, D-20, D-30 and D-40). Each treatment was conducted in three repetition. The results showed that the time observation gave significantly different on water condition changes (P <0.05), which will increase TSS, turbidity and chlorophyll value along with the increasing of time. P exilis in aquaponics was effective in reducing turbidity and chlorophyll concentration (P <0.05). Therefore, aquaponics system with the highest mussels density (P3) with has lower turbidity and chlorophyll value than the one with 0 mussels density (P1).