Otolith-based age and growth of the spotted moray eel (Gymnothorax moringa) and squirrelfish (Holocentrus adscensionis) from Ascension Island and St Helena"

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

doi:10.3389/fmars.2025.1705888

ORIGINAL RESEARCH article

Front. Mar. Sci.

Sec. Marine Biology

This article is part of the Research TopicCurrent Research on Fish Otoliths and their ApplicationsView all 13 articles

Otolith-based age and growth of the spotted moray eel (Gymnothorax moringa) and squirrelfish (Holocentrus adscensionis) from Ascension Island and St Helena"

Provisionally accepted

Elizabeth Laman Trip¹

Ian Woodgate²

Tiffany Simpson³

James B. Bell²

Paul Whomersley²

Leeann Henry⁴

Kirsty Jones⁴

Kyne Krusic-Golub⁵

Simon Robertson⁵

Serena Wright²

Valerio Visconti^2*

¹Halieumer, Arzon, France
²Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Lowestoft, United Kingdom
³Ascension Island Government, Georgetown, Saint Helena
⁴Environment and Natural Resources Directorate - St Helena Government, Jamestown, Saint Helena, United Kingdom
⁵Fish Aging Services Pty Ltd, Victoria, Australia

The final, formatted version of the article will be published soon.

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 fish 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. The study highlights the importance of developing locality-specific species life history data collections to monitor population dynamics in MPA areas. This biological information is essential to allow future assessment programs on the potential impacts of climate change and inshore human activities, including the impacts of inshore fisheries. 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.

Keywords: Blue Belt, Fisheries, Growth, otoliths, Southern atlantic, United Kingdom overseas territory

Received: 15 Sep 2025; Accepted: 11 Nov 2025.

Copyright: © 2025 Laman Trip, Woodgate, Simpson, Bell, Whomersley, Henry, Jones, Krusic-Golub, Robertson, Wright and Visconti. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Valerio Visconti, valerio.visconti@cefas.gov.uk

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