Innovation for sustainable pearl farming: biodegradable solutions to mitigate plastic pollution

The fate of plastic waste is a global concern, particularly in insular regions with limited waste management infrastructure. In pearl farming, disposable PP shade-mesh collectors used to recruit Pinctada margaritifera spat are a persistent source of plastic pollution. Although reusable HDPE plates improve recruitment performance, their long-term fate remains problematic. To mitigate plastic waste in aquaculture, two biodegradable collector prototypes were tested under real farming conditions in French Polynesia over 13 months: BioM, a novel biodegradable polymer blend tailored for spat collection, and coconut coir geotextile. At 6 months, BioM recruited significantly more spat than both conventional collectors (P < 0.05). By 13 months, mean densities were 3.46 ± 2.78 × 10 −4 (BioM), 2.47 ± 1.17 × 10 −4 (HDPE plates), and 1.49 ± 1.07 × 10 −4 individuals·cm −2 (shade-mesh): BioM and plates both exceeded shade-mesh (P < 0.05), while the BioM–plates difference was not significant. In contrast, coconut-based collectors exhibited rapid degradation (within 7 months) and recruitment similar to shade-mesh, underscoring current limitations. These results provide the first in situ evidence of biodegradable polymers functioning effectively in pearl farming applications. Beyond performance, BioM collectors provide an eco-designed solution that addresses both plastic pollution and the need for sustainable materials in marine-based industries. They offer a pathway to reduce persistent plastic inputs, promote healthier marine ecosystems, and align aquaculture practices with circular economy and green engineering principles. However, further durability optimization will be needed to ensure their long-term effectiveness, paving the way for broader adoption in bivalve farming. • Novel biodegradable collectors were tested in situ for pearl oyster spat collection. • BioM were 1.3–3.8 times more efficient than traditional spat collectors. • Coconut-based collectors degraded rapidly and had low spat collection efficiency. • BioM reduces plastic waste but requires improved durability for long-term use. • Biopolymer-based collectors show promise for sustainable bivalve farming.