Authors: E.T. Tsakiris, C.R. Randklev, and K.W. Conway

Studies on the reproductive biology of freshwater mussels have contributed to conservation of this group, but methods to study early reproductive stages are either lethal (e.g., histological technique) or useful for only qualitative assessments (e.g., nonlethal syringe technique). Using 2 common mussels (Quadrula apiculata and Quadrula verrucosa) and 2 rare mussels (Quadrula petrina and Quadrula houstonensis) distributed across 3 sites in the Navasota River and San Saba River, Texas, we validated the effectiveness of the syringe technique to quantify gamete production by examining: 1) if estimates of gamete traits (sperm concentration, egg size, and egg concentration) obtained with the syringe technique were correlated to estimates of gamete traits (sperm density, egg size, and egg density) obtained with a histological technique; and 2) if survival, growth, and body condition of individual mussels sampled with the syringe technique were negatively affected in a 2-y mark–recapture field experiment. Pearson’s correlation analysis of gamete production measured over the 1st year of the study indicated sperm concentration and density and egg sizes were correlated between the 2 techniques; however, egg concentration and density were correlated in only some cases. Joint analysis of live and dead encounters from the mark–recapture experiment indicated the syringe technique had little to no effect on survival probability of mussels, and mixed models of shell growth and Fulton’s K body condition index failed to detect sublethal effects of the syringe technique on mussels. The syringe technique is relatively accurate and noninvasive and can be used to study the reproductive biology of threatened and endangered mussels quantitatively. In addition, it can provide the large sample sizes often needed to study the reproductive ecology of mussels

Suggested Citation

Tsakiris, E.T., C.R. Randklev, and K.W. Conway. 2016. Effectiveness of a nonlethal method to quantify gamete production in freshwater mussels.Freshwater Science. 35:3, 958-97.