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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #436226
Research Project: Genetic Improvement of Catfish for Aquaculture Production Efficiency

Location: Warmwater Aquaculture Research Unit

Title: Assessment of pulsed gastric lavage for diet sampling in two new world cichlid taxa

Author
item MORELAND, JACOB - Mississippi State University
item NEAL, J - Mississippi State University
item ALLEN, PETER - Mississippi State University

Submitted to: North American Journal of Fisheries Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2025
Publication Date: 10/7/2025
Citation: Moreland, J.A., Neal, J.W., Allen, P.J. 2025. Assessment of pulsed gastric lavage for diet sampling in two New World cichlid taxa. North American Journal of Fisheries Management. 45(6). https://doi.org/10.1093/najfmt/vqaf070.
DOI: https://doi.org/10.1093/najfmt/vqaf070

Interpretive Summary: Two invasive fish species that also have aquaculture potential were investigated for best methods to sample stomach contents in order to determine diet. It was found that gastric lavage for diet studies is relatively ineffective and damaging to two New World cichlids (Jaguar Guapote and Amphilophus species). The recommendation to sample stomach contents is via euthanasia and dissection, especially where these taxa are invasives. This research supports the Secretary of Agriculture’s priorities of increasing profitability of farmers and creating new uses of U. S. agricultural products.

Technical Abstract: Objective: The use of gastric lavage in fish dietary studies can eliminate the need for lethal extraction of stomachs but can vary in efficacy and cause physical damage due to anatomical variability in species. Gastric lavage has not been evaluated with many New World cichlid species. The objective of this study was to determine the efficacy of lavage techniques for diet analysis compared with destructive sampling for Jaguar Guapote Parachromis managuensis and members of the Amphilophus genus, which are common invasive New World cichlids in tropical and subtropical environments. Methods: We compared pulsed gastric lavage to destructive sampling for diet assessment in Jaguar Guapote and the Amphilophus genus in terms of efficacy and potential for injury. The comparison was conducted using quarterly in situ sampling within three nonnative reservoir assemblages in Puerto Rico. Results: The percentage of total diet extracted using pulsed gastric lavage was moderate (51.2 ± 4.9%) for Jaguar Guapote and low (14.0 ± 3.9%) for Amphilophus spp., and efficacy was greater for Jaguar Guapote compared with Amphilophus spp. during three of four seasons. The lavage technique resulted in light bruising of the stomach wall (25% of Jaguar Guapote and 15% of Amphilophus spp.), intense bruising and swelling (10% of Jaguar Guapote and 5% of Amphilophus spp.), and punctures, tears, and inversion of the stomach (prolapse; 5% of individuals of each taxon). Conclusions: These results suggest that destructive sampling is the most appropriate technique for both taxa and that the use of gastric lavage on sampling diet of Amphilophus spp. is not recommended due to very low efficacy. Further, although this sampling method is labeled as nonlethal, up to 40% of fish sampled sustained injury.