A conceptual framework to inform conservation status assessments of non-charismatic species.

The conservation of at-risk species is rooted in the ability of natural resource agencies to recognize when a species is imperiled and in need of regulatory action, which can be a difficult task due to incomplete information. Freshwater mussels (Bivalvia: Unionidae), are a highly imperiled group of aquatic organisms and conservation tools such as the NatureServe Conservation Methodology provide a framework to determine whether a species is in decline and in need of potential management. For data deficient species like mussels this method relies heavily on expert opinion, which can lead to biased estimates of conservation status that may not reflect the true nature of their conservation need.

Evaluation of survivorship and annulus validation in calcein-stained freshwater unionid mussels.

Unionid mussels deposit growth rings (annuli) within the shell, which can be used to estimate age and growth. Thin-sectioning is a common technique for counting annuli, wherein a cross-section of a shell valve is taken and evaluated by multiple readers. Correctly identifying annuli can be challenging because ambiguous annuli can bias growth estimates.