Environmental controls on long-term growth of freshwater mussels in an oligotrophic lake

Abstract

Freshwater mussels are one of the most endangered groups of animals and live in some of the fastest changing ecosystems in the world. Unfortunately, very little is known about how their life history and ecology are influenced by their environment, especially for lake-dwelling populations. In this study, we paired ∼30 y of extensive environmental data to lifetime and annual growth rates of a population of Fatmucket mussels (Lampsilis siliquoidea) living in a cool-water oligotrophic lake in northern Wisconsin, USA. This population displayed one of the slowest growth rates and longest lifespans within its phylogenetic tribe (Lampsilini). Growth rates were highly variable between individuals and, in contrast to studies in other systems, not related to temperature, growing season, or any indicators of primary production. However, growth rates were positively correlated with changes in lake level. We hypothesize that mussel growth in this system is linked to landscape-level environmental conditions and allochthonous resource limitation.