Prey regurgitation and stomach vacuity among groupers and snappers

Abstract

International audiencePrey regurgitation during capture is a potential important confounding effect in fish dietary ecology studies as it may lead to overestimation of stomach vacuity and underestimation of prey consumption. This study investigates patterns of prey regurgitation and stomach vacuity among five grouper and three snapper species in shallow water off French Polynesia and tests the effectiveness of piercing swim-bladders after capture as a method to prevent regurgitation. Groupers exhibited a moderate overall regurgitation rate of 15.6% of full stomachs and a high true (i.e., after accounting for regurgitation) stomach vacuity rate of 40.5%. In contrast, snappers showed high regurgitation (mean 31.7%) and low true stomach vacuity (14.6%). Not accounting for regurgitation would have resulted in a moderate overestimation of stomach vacuity in groupers, but an almost 3-fold overestimation in snappers. Swim-bladder decompression by piercing after capture prove a highly effective method to reduce regurgitation (more than 2-fold for groupers and near 8-fold for snappers). This study enables a more general understanding of prey regurgitation in two commercially valuable fish families, thus improving understanding of the dietary ecology of these fishes. This information is particularly important in the context of prey consumption estimates and subsequent estimations of the impact of fish predators on ecosystems

Feeding Habits of the Blue Shark (Prionace glauca) in the Northwestern Pacific Based on Stomach Contents and Stable Isotope Ratios

“…A regime shift is a persistent change in an ecosystem's structure and function, which can be abrupt and difficult to reverse. Some authors have criticized stomach contents analyses for being merely a snapshot sample (e.g., Basker et al 2014), and some biases have occurred from regurgitation during capture ( Vignon and Dierking 2011). Therefore, analyzing stomach contents reveals only the short-term feeding habits of animals.…”

Ontogenetic and seasonal shifts in the diet ofDiplodus cervinus hottentotus(Pisces: Sparidae) in southern Angola

“…Using spearfishing, death is instantaneous -which results in reduced post-capture digestion and regurgitation -and actively foraging fish are not selected. Spearfishing, however, has been criticised as a collection method by Vignon and Dierking (2011) Error bars depict 95% confidence intervals stomach is everted as a result of barotrauma. This concern, however, was based on fish that had been speared at depths >20 m, using SCUBA gear.…”

Trophic ecology of an abundant predator and its relationship with fisheries

“…For example, regurgitation during the fishing process can lead to information loss and to the underestimation of prey importance (e.g. Sutton et al 2004, Vignon & Dierking 2011. This can be particularly important in dietary analysis of elasmobranchs, as many species are able to evert their stomachs with no apparent ill effects (Simpfendorfer et al 2001, Barnett et al 2010b.…”