Exploring the Impacts of Methylmercury‐Induced Behavioral Alterations in Larval Yellow Perch in Lake Michigan Using an Individual‐Based Model

Abstract

The inclusion of sublethal behavioral effects in population models has predicted lower estimates of cohort abundance and survival. Methylmercury, a persistent contaminant in the Great Lakes, has been shown to alter foraging and predator avoidance behaviors of larval Yellow Perch Perca flavescens, which may have indirect effects on recruitment. Poor recruitment of Yellow Perch in Lake Michigan has been associated with changes in trophic structure and adverse habitat conditions, but the potential effects of contaminants have not been fully explored. To test this, we adapted existing larval fish individual-based models to incorporate laboratory-derived methylmercury behavioral impairments on a larval Yellow Perch cohort in Lake Michigan. Overall, swimming speed reductions following methylmercury exposure did not drastically affect cohort survival. In contrast, the impairment to prey capture success resulted in an additional 8, 45, and 28% starvation of the cohort in simulations with tissue concentrations of 0.21, 0.95, and 3.14 μg/g total mercury whole-embryo wet weight, respectively. While our experimental methylmercury concentrations were higher than those typically found in Lake Michigan, our findings suggest that contaminants could be an additional factor impacting recruitment of Yellow Perch in systems highly contaminated with mercury.

An ecotoxicological view on neurotoxicity assessment

“…Embedding behaviour into an AOP that predicts ecologically relevant adverse outcome is challenging because it is difficult to interpret subtle changes in behaviour in terms of population demographics. There have been some development in methods to link behavioural outcomes to population relevant impacts that are suitable for ecological risk assessment [321–324]. As fish larvae are particularly sensitive to predation and starvation, impaired behaviour related to foraging and predator avoidance may have drastic consequences to the individual [325].…”

“…These behaviours can be related to the probability of escaping a predator, capturing prey for feeding and encounter rates using statistical models. Some examples of directed laboratory studies that were used to focus on behaviour relevant to ecological processes such as foraging and predator avoidance and subsequently used to construct an individual based model calibrated for particular species and populations are available [323, 324].…”

“…The associations between measurable disruptions in brain gene expression measured using RNAseq, metabolomics and reverse engineering, and probabilities of capturing prey and avoiding predators can then be incorporated into a larval fish cohort model (e.g. [321, 322, 324, 326]), to predict survival and growth of the cohort. Cohort survival and growth can also be easily translated into parameters relevant to common metrics used by regulatory agencies (e.g.…”

Altered Larval Yellow Perch Swimming Behavior Due to Methylmercury and PCB126 Detected Using Hidden Markov Chain Models

“…In addition, new artificial intelligence animal behavior tools continue to be developed that will aid in the application of these methods to high-throughput applications. ,, However, the key in applying individual animal behavior endpoints in management actions is making them relevant to the population level such as through growth and/or survival . To date, the application of individual behavior endpoints to population-level impacts has mainly been through the use of individual-based modeling , or Leslie matrix population models, where the results from this study will be applied. Consequently, combining random walk models within the individual-based modeling framework is needed in order to apply the HMM results from this study to population-level impacts.…”

“…Our objective is to determine how neurotoxicant pollutants altered spontaneous swimming of larval fish by examining endpoints that summarize swimming characteristics over the entire behavioral assay and also those that examine swimming patterns that represent different behavior states within an assay such as different types of swimming. These behavior observations could be used in future work to model impacts of pollution on the growth and survival of larval fish (e.g., refs , ).…”