Lower Lethal Temperatures for Nonnative Freshwater Fishes in Everglades National Park, Florida

Abstract

Temperature is an important factor that shapes biogeography and species composition. In southern Florida, the tolerance of nonnative freshwater fishes to low temperatures is a critical factor in delineating their geographic spread. In this study, we provide empirical information on experimentally derived low‐temperature tolerance limits of Banded Cichlid Heros severus and Spotfin Spiny Eel Macrognathus siamensis, two nonnative Everglades fishes that were lacking data, and African Jewelfish Hemichromis letourneuxi and Mayan Cichlid Cichlasoma urophthalmus, species for which previous results were derived from studies with small sample sizes. We also provide a literature review summarizing the current state of knowledge of low‐temperature tolerances for all 17 nonnative freshwater fishes that have been found in Everglades National Park. Mean lower lethal temperature tolerances ranged from 4°C (Orinoco Sailfin Catfish Pterygoplichthys multiradiatus) to 16.1°C (Butterfly Peacock Bass Cichla ocellaris). These low‐temperature limits may inform the understanding of the ecological role or influence of nonnative fishes and may lead to potential management opportunities and applications.

Quantifying habitable water temperatures and thermal sensitivities among species functional traits of stream invertebrates

“…Most aquatic species, such as invertebrates, are ecothermic and therefore have body temperatures that reflect their environment to varying degrees (Angilletta, 2009;Sinclair et al, 2016). Extremely high or low temperatures are lethal, and temperature determines all cellular and physiological functions, including metabolism, development, growth, migration, and reproduction and indirectly throughout changes in prey community and environments (Grigaltchik et al, 2012;Ylla et al, 2014;Nelson et al, 2020b;Schofield & Kline, 2018;Shah et al, 2021). Changes in water temperature have serious implications at population, community, and ecological levels (e.g., Grigaltchik et al, 2012;Sinclair et al, 2016), especially given the uncertainty in how stream temperature regimes may change with different climate and land-use changes (Kominoski & Rosemond, 2012).…”