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Fish communities of tropical lakes are commonly predicted by local environmental variables, including depth, temperature, oxygen concentration, and substrate composition. Increasingly, however, lacustrine fish communities are being impacted by invasive species. In the state of Quintana Roo, on the Caribbean versant of the Yucatan Peninsula in Mexico, inland aquaculture production has resulted in the widespread establishment of African tilapia (Oreochromis sp.). However, there are still limited quantitative data on their abundance relative to indigenous species, or their influence on native fish diversity. Here, we quantified the ichthyofauna of six lakes from this region, alongside physical and chemical environmental variables. Overall, we observed that greater dissolved oxygen concentration and shallower depths were associated with the highest fish biodiversity across lakes. Moreover, spatial comparisons additionally highlighted the importance of substrate heterogeneity and lake area as influential in determining native fish community structure. Notably, in all lakes, tilapia were relatively uncommon, comprising less than 3% of all fish captured, and their presence was not a significant predictor of indigenous fish biodiversity. Based on these results, we suggest that tilapia may have strong limitations on their population size, plausibly due to the presence of predatory native fish species, or scarce suitable ecological resources (food, breeding habitat). Conservation-focussed lake-wide management of native species via protection of core habitat characteristics may be key to promoting environmental resistance against negative effects of tilapia regional expansions. [ABSTRACT FROM AUTHOR]

Freshwater fish are in a perilous state with more than 30% of species considered critically endangered. Yet significant ecological and methodological complexities constrain our ability to determine how disturbances are impacting native fish communities. We review current methods used to assess the responses of fish communities, especially native fish, to disturbances, with a focus on lakes. These methods include contemporary population surveys, manipulative experimental approaches, paleolimnological approaches and Indigenous Knowledge and social histories. We identify knowledge gaps, such as a lack of baseline data for native fish, an inability to assess the impact of historical disturbances, stressor response dynamics in contemporary multi‐stressor environments, and natural disturbance regimes. Our assessment of the current methods highlights challenges to filling these knowledge gaps using the reviewed methods. We advocate strongly for the implementation of an integrative approach that combines emerging technologies (i.e. molecular‐based techniques in contemporary surveys and paleolimnology) and underutilised knowledge streams (i.e. Indigenous Knowledge and social histories) which should be used in concert with conventional methods. This integrative approach will allow researchers to determine the key drivers of decline and the degree of change, which will enable more informed and successful management actions. [ABSTRACT FROM AUTHOR]