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Fish eyes: windows to understanding trophic ecology, movement, and residency of a potential invader across the Panama Canal

par Enos, Ethan
Promoteur Tricarico, Elena
Co-Promoteur Castellanos-Galindo, Gustavo Adolfo;Torchin, Mark
Publication Non publié, 2024-08-29

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Résumé :

The completion of the Panama Canal in 1914 opened a conduit for interoceanicinvasions between the Pacific Ocean and the Caribbean Sea. At the center of the canal,freshwater Lake Gatun serves as a barrier, restricting the passage of potential marine invadersbetween ocean basins. Since its creation, marine fish species have appeared within thefreshwater lake, but only few species completed an interoceanic invasion. To understand thepotential of euryhaline marine fish species to successfully cross the Isthmus, we mustdetermine their ability to persist and expand within this freshwater habitat. The common snook(Centropomus undecimalis), a predatory fish from the Atlantic Ocean, is one species commonlyfound throughout the Panama Canal. We used stable isotope analysis (SIA) of fish eye lenses, anarchival tissue type, to examine individual common snook trophic ecology across ontogeny. Weused mixing models in MixSAIR to distinguish between the marine and freshwater foraging andunderstand their trophic resource use in the Panama Canal. We determined that commonsnook likely enter Lake Gatun at small juvenile sizes (< 50 mm standard length) and reside in thecanal into adulthood. Juvenile common snook in Lake Gatun rely heavily on the pelagic trophicpathway and begin to diversify their diet as they grow. Long residency times of common snookin the Panama Canal could potentially increase their chances of completing a cross-isthmianinvasion. SIA of fish eye lenses could be a valuable method for understanding certainmechanisms of real-time invasions taking place at the Panama Canal.