Title: Assessing stock abundance, size, and spatial distribution of five CITES-listed sea cucumber species in Papua New Guinea.

The sea cucumber fishery plays a crucial role in Papua New Guinea's coastal economy, providing significant annual revenue and direct benefits to local communities. In response to declining sea cucumber populations, a fishery moratorium was introduced in 2010, prompting comprehensive stock assessment surveys conducted by the National Fisheries Authority across various provinces. By 2020, a Non‑Detrimental Finding (NDF)—which determines whether export of a species is non‑detrimental to its survival—permitted the trade of two teatfish species under CITES, with three additional species approved in 2022 and effective from 2024. In this study, management strategies are investigated, including NDF implementation, by thoroughly evaluating stock assessment data.

The results indicate that Candy cane (Thelenota rubralineata) was uncommon, with significantly lower density compared to White teatfish (Holothuria fuscogilva), Black teatfish (H. whitmaei), Prickly redfish (Thelenota ananas), and Amberfish (T. anax). A partial recovery was observed in White teatfish and Prickly redfish, suggesting a positive trend in abundance and recruitment during the moratorium period. However, populations of Black teatfish exhibited fluctuations, and Amberfish showed inconsistencies. Size distribution analysis revealed compliance with NFA regulations, although discrepancies were noted for Black teatfish and Prickly redfish regarding legal size requirements.

Recommendations include using 2016 mean density as a reference point and revising the sizes of Black teatfish and Prickly redfish to ensure they exceed the size at maturity. Additionally, a complete ban on Candy cane from the fishery and targeted stock assessment surveys were proposed.