North American Freshwater Mussels: Natural History, Ecology, and Conservation

Mussels have a complex life cycle wherein their larvae are obligate ectoparasites on fish.

“Mussels have a complex life cycle wherein their larvae are obligate ectoparasites on fish (Haag, 2012).”

Fish assemblage structure plays a substantial role in determining mussel assemblage composition.

“Thus, fish assemblage structure plays a substantial role in determining mussel assemblage composition.”

The trilateral life history model was originally developed from analysis of life history variation in fishes and later applied to other taxa including mussels.

“The trilateral life history model reflects trade-offs between juvenile survival, fecundity, and generation time (Figure 1A; Haag, 2012;Winemiller & Rose, 1992) and was originally developed from analysis of life history variation in fishes and later applied to other taxa including mussels (Haag, 2012;Moore et al., 2021).”

Both mussel and fish broad-scale distributions and richness are constrained by large macroscale processes, i.e., historical contingencies.

“Both taxonomic groups are constrained in their broad-scale distributions and richness by large macroscale processes (i.e., historical contingencies; Haag, 2012;Hocutt & Wiley, 1986), thus asking how watershed size as a proxy for disturbance shapes patterns of richness and trait composition is most appropriate at a regional scale (Matthews & Marsh-Matthews, 2017;Poff, 1997).”

The trilateral life history model reflects trade-offs between juvenile survival, fecundity, and generation time.

“The trilateral life history model reflects trade-offs between juvenile survival, fecundity, and generation time (Figure 1A; Haag, 2012;Winemiller & Rose, 1992) and was originally developed from analysis of life history variation in fishes and later applied to other taxa including mussels (Haag, 2012;Moore et al., 2021).”

Mussel species were assigned to the equilibrium, periodic, or opportunistic life history strategy as in Haag (2012).

“Mussel species were assigned to the equilibrium, periodic, or opportunistic life history strategy (Appendix S1: Table S1) as in Haag (2012).”

The concordance in life history strategy distribution between mussels and fish may be because fish are hosts for the larval stage of mussels.

“This concordance may be because fish are hosts for the larval stage of mussels (Haag, 2012).”

The lack of relationship for opportunistic mussel species may be because the study design primarily focused on mussel assemblages associated with mussel beds typically found in hydrologically stable stream habitats where opportunistic species are rarely found.

“For mussels, this may be because our study design primarily focused on mussel assemblages, which are associated with mussel beds that are typically found in hydrologically stable stream habitats where opportunistic species are rarely found (Haag, 2012).”

Mussels depend on host fish for dispersal and are only abundant and diverse where fish are abundant and diverse.

“Because mussel adults are sedentary, mussels depend on host fish for dispersal and are only abundant and diverse where fish are abundant and diverse (Haag, 2012).”