A Review of the Giant Triton (Charonia tritonis), from Exploitation to Coral Reef Protector?

Abstract

Charonia tritonis (Charoniidae), one of the largest marine gastropods and an echinoderm specialist, preys on Crown-of-Thorns starfish (CoTS), a recurring pest that continues to be a leading cause of coral mortality on Indo-Pacific reefs. Widespread historical exploitation has impacted their numbers, with standing populations considered rare throughout their habitat. Their life-stage attributes, i.e., teleplanic larvae, planktotrophic phase spanning years permitting transoceanic dispersal, and recruitment to coral reefs through oceanic influx with intense larval mortality, have likely hindered their recovery. Decline in numbers is hypothesised to account partially for periodic CoTS outbreaks, yet predator-prey dynamics between these two species that might influence this are poorly understood. The C. tritonis excretory secretome elicits a proximity deterrence effect on CoTS, the nature of which is under investigation as a possible tool in CoTS biocontrol scenarios. However, specificity and zone of impact in situ are unknown, and whether the mere presence of C. tritonis and/or predation pressure has any regulatory influence over CoTS populations remains to be established. The fundamental taxonomy and distinctive characteristics, biology and ecology of C. tritonis is summarized, and knowledge gaps relevant to understanding their role within coral reefs identified. Information is provided regarding exploitation of C. tritonis across its habitat, and prospects for conservation interventions, including captive rearing and stock enhancement to repopulate local regions, are discussed. Its predator-prey ecology is also examined and potential to mitigate CoTS considered. Recommendations to direct future research into this predator and for its inclusion in a CoTS integrated pest management strategy to improve coral reef health are offered.

Complete mitochondrial genome of the giant triton snail Charonia tritonis (Tonnoidea: Charoniidae)

“…Species identification was based on features such as smooth, broad, and flattened spiral ribs with wavy, puckered edges, and a broad, short siphonal canal with thin folds along the columellar wall (Motti et al. 2022 ). The specimens have been deposited at the Specimen Museum of the School of Marine Biology and Fisheries at Hainan University ( http://en.hainanu.edu.cn/ , Xiang, Xiangzhang@hainanu.edu.cn ), with voucher numbers ctri20181201 and ctri20181202.…”

The voice of the Adriatic? The Keszthely triton conch trumpet

“…Triton trumpet conches are widespread in tropical, subtropical and Mediterranean waters, including the Mediterranean and Adriatic Seas (Motti et al 2022). The colour of the Keszthely specimen (Fig.…”

Novel rubble-dwelling predators of herbivorous juvenile crown-of-thorns starfish (Acanthaster sp.)

“…These claims followed the first documented outbreak on the Great Barrier Reef (GBR) in Australia, coinciding with exhaustive fishing-induced depletion of the giant triton, Charonia tritonis, a predator of adult CoTS (Endean 1973). However, the effectiveness of predation by C. tritonis on CoTS remains unresolved (Ormond et al 1990;Motti et al 2022), given that reported consumption rates are low, < 1 wk −1 (Endean 1969;Birkeland 1989b), and their historical (cf. pre-harvest) densities are unknown (Hall et al 2017).…”