Solomon Islands largest hawksbill turtle rookery shows signs of recovery after 150 years of excessive exploitation.

Richard J Hamilton,Collin Gereniu,Richard Walter,Peter C Ramohia,Clara Goerlich,Colin Limpus,Tomas Bird,John Pita

doi:10.1371/journal.pone.0121435

Abstract

The largest rookery for hawksbill turtles in the oceanic South Pacific is the Arnavon Islands, which are located in the Manning Strait between Isabel and Choiseul Province, Solomon Islands. The history of this rookery is one of overexploitation, conflict and violence. Throughout the 1800s Roviana headhunters from New Georgia repeatedly raided the Manning Strait to collect hawksbill shell which they traded with European whalers. By the 1970s the Arnavons hawksbill population was in severe decline and the national government intervened, declaring the Arnavons a sanctuary in 1976. But this government led initiative was short lived, with traditional owners burning down the government infrastructure and resuming intensive harvesting in 1982. In 1991 routine beach monitoring and turtle tagging commenced at the Arnavons along with extensive community consultations regarding the islands’ future, and in 1995 the Arnavon Community Marine Conservation Area (ACMCA) was established. Around the same time national legislation banning the sale of all turtle products was passed. This paper represents the first analysis of data from 4536 beach surveys and 845 individual turtle tagging histories obtained from the Arnavons between 1991-2012. Our results and the results of others, reveal that many of the hawksbill turtles that nest at the ACMCA forage in distant Australian waters, and that nesting on the Arnavons occurs throughout the year with peak nesting activity coinciding with the austral winter. Our results also provide the first known evidence of recovery for a western pacific hawksbill rookery, with the number of nests laid at the ACMCA and the remigration rates of turtles doubling since the establishment of the ACMCA in 1995. The Arnavons case study provides an example of how changes in policy, inclusive community-based management and long term commitment can turn the tide for one of the most charismatic and endangered species on our planet.

Highlights

Sea turtles are considered flagship species for conservation and their plight has captured widespread attention
In the process of cross checking the 1991–2012 Kerehikapa database we discovered one hawksbill turtle that was initially tagged as a juvenile in the northern Great Barrier Reef (GBR), Australia [27]
Our findings build upon earlier research which has shown that Solomon Islands hawksbill turtles are a shared resource, with many of the hawksbills that nest in Solomon Islands having migrated from their foraging grounds in Australia, Torre Straits and Papua New Guinea [31]

Summary

Introduction

Sea turtles are considered flagship species for conservation and their plight has captured widespread attention. Worldwide declines in sea turtle populations have primarily been attributed to excessive exploitation with global catches peaking at over 17,000 tonnes in the late 1960s [1]. In Solomon Islands the critically endangered hawksbill turtle (Eretmochelys imbricata) has formed an important component of the cultural value systems and subsistence economies for centuries [6, 7], and it played a central role in early commercial exchange with Europeans. Trade between Europeans and islanders from New Georgia archipelago in the Western Province of Solomon Islands started in the first decades of the nineteenth century and by 1840 by far the most important trade item was the shell of hawksbill turtles [8, 9]

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