Ensuring the Sustainability of Coastal Small-Scale Fisheries at Pitcairn Island (South Pacific) Within a Large Scale No-Take MPA

Abstract

The Pitcairn Islands, located in the central South Pacific, contain near-pristine marine ecosystems which support unique fish assemblages, together with both endemic and threatened species. Pitcairn itself is the only inhabited island in the group and, before this study, the environmental impact of local fisheries was unclear, with little data to inform conservation and management. In 2014–2015 coastal fish populations were assessed using a mixed methods approach: a newly introduced system of fishers’ catch monitoring and Baited Remote Underwater Video Systems (BRUVS). Thirty-nine BRUVS deployments recorded 88 species in total, with small-bodied herbivores (e.g., Kyphosus pacificus) and mesopredators (e.g., Xanthichthys mento) dominating a “bottom heavy” assemblage. Several large pelagic predators were recorded, but reef-associated predators were rare with only one shark observed. Pitcairn’s top predator assemblage was relatively impoverished compared to global “pristine” sites, including other islands within the Pitcairn group. Top predator scarcity may be explained by local artisanal fisheries, which have historically targeted sharks and other large reef carnivores, and these taxa may not have recovered despite subsequent declines in fishing pressure. The dominant small-bodied species may have proliferated as a result of diminished top predator populations. Subsequent to BRUVS sampling, a local fisheries officer post was created to collate catch data from coastal fishers. Regular returns were obtained from over half of the active fishers (representing approximately 80% of catches), with K. pacificus also dominating catches and the small grouper Epinephelus fasciatus frequently targeted. Thirty fish species were represented in the recorded catch over a 12 month period. Results were shared with the local community, providing a basis for the cooperative design of a Fisheries Management Plan. This plan ensured traditional fisheries could continue in a sustainable manner within Coastal Conservation Zones around each of the four Pitcairn Islands, established within the large, no-take Marine Protected Area designated in 2016, covering the entire Pitcairn Exclusive Economic Zone. Monitoring of Pitcairn’s artisanal fisheries should be continued beyond this one-off study in order to inform adjustment of the Fisheries Management Plan, as the ongoing island fishery may still have consequences for long-term sustainability, particularly for pelagic species caught in coastal waters which remain a significant data gap.

Rapid Assessment of Seabed Habitats Around Pitcairn Island in Aid of Activity Management During the COVID-19 Global Pandemic

“…The initial results were delivered to the Pitcairn Islands within a month of the COVID-19 pandemic interrupting shipping movements. The habitats identified through this study are similar to those identified during previous work (Friedlander et al, 2014;Duffy et al, 2021) but have now been associated with a spatial distribution. The data produced here have fed directly into the management of the anchoring around Pitcairn Island.…”

“…The habitat classifications from this study were converted to those of the historical studies to undertake the accuracy assessment. Out of a total of 63 data points [26 from Friedlander et al (2014) and 37 from Duffy et al (2021)], 43 (68%) were found to be in agreement with the new predictive habitat map based on the relationships in Table 3. Comparison between the two historical datasets separately produced quite variable results.…”

“…The comparison with the Friedlander et al (2014) study showed an accuracy of 96% of samples being in agreement. However, the comparison with the results from Duffy et al (2021) scored much lower with 49% of samples in agreement.…”

“…The first was collected in 2012 as part of the National Geographic Pristine Seas Expedition (Friedlander et al, 2014), which undertook diver transects at 26 locations around Pitcairn Island. The second dataset was collected as part of a Darwin Initiative funded project looking at fish stocks (Duffy et al, 2021), which collected video data using baited remote underwater video cameras at 37 locations within the mapped area. As the datasets were collected and analyzed using different methods comparisons are made against the estimated habitats from each dataset against the derived habitats from the analysis here to give an indicative accuracy assessment.…”

Climate change impacts on the coral reefs of the UK Overseas Territory of the Pitcairn Islands: resilience and adaptation considerations

“…Predatory fish are also important to keep smaller, corallivorous fish, and other trophic groups in check and therefore preserve a healthy functional reef. Previous fish assessments indicate that whilst fish communities in the Pitcairn Islands are relatively healthy, numbers of sharks and groupers have been locally impoverished due to targeted catches (Friedlander et al ., 2014; Coghlan et al ., 2017; Dawson & Irving, 2020; Duffy et al ., 2021).…”