Publication Abstract

This study investigates the age-based life-history traits of two groundfish species, the spotted moray eel (Gymnothorax moringa) and squirrelfish (Holocentrus adscensionis), found in Ascension Island and St Helena. Both islands are part of the UK Overseas Territories (UKOTs) and are known for their biodiversity. The research aims to provide essential life-history information to support sustainable management of these species within the Marine Protected Areas (MPAs) of Ascension Island and St Helena.

A total of 556 fish samples were collected between 2014 and 2021, with 279 individuals of G. moringa and 277 individuals of H. adscensionis. We found significant differences in life span, adult body size, and growth rates between the two islands for both species. G. moringa exhibited longer life spans (32 vs 29 years) and faster growth rates at Ascension Island compared to St Helena, while H. adscensionis showed larger adult sizes at Ascension Island but shorter life spans (21 vs 27 years) compared to St Helena.

Environmental factors such as sea surface temperature, habitat productivity, and exposure to currents were identified as potential key influences on the observed differences in life-history traits. The study highlights the importance of localised data collection and long-term monitoring to understand the impacts of climate change and human activities on these species. Future research should focus on reproductive biology, size and age at maturity, and migration patterns to enhance the accuracy of sustainability assessments for these fisheries.

Elizabeth D. L. Trip, Ian Woodgate, Tiffany Simpson, James B. Bell, Paul Whomersley, Leeann Henry, Kyne Krusic-Golub, Simon Robertson, Serena Wright, Valerio Visconti