Silver shiner, Notropis photogenis, fecundity and parasite infections during the reproductive period

Abstract

The reproductive period is a critical part of a species’ life history. Estimating species-specific fecundity can improve demographic models aimed at developing recovery targets for imperilled species. We provide egg diameter and fecundity estimates and develop a length–fecundity relationship for silver shiner, Notropis photogenis (Cope, 1865), a small-bodied freshwater species listed as Threatened under Canada's Species at Risk Act. Furthermore, we document the incidence of an acanthocephalan parasite, the thorny-headed worm, Leptorhynchoides thecatus (Linton, 1891), in the gastrointestinal tract of silver shiner, which is the first published record of the parasite in this species. Silver shiner egg diameters (mean ± standard deviation) were 0.61 ± 0.15 mm and ranged from 0.13 to 0.92 mm. Fecundity ranged from 311 to 2768 eggs and was significantly higher in age 2–3+ fish (1475 ± 570 eggs) compared with age 1+ fish (576 ± 270 eggs). We highlight that parasite infection negatively impacted the body condition of individuals and that additional work is needed to determine the impact of parasite infestation on reproductive output, recruitment, susceptibility to predation, and survival of silver shiner in Canada. The fecundity and egg diameter estimates for Canadian silver shiner provided here can be incorporated into future populations modelling for this threatened species.