Conservation & Research Department, PI: Dr. Andrew Kouba

Memphis Zoo

Amphibians are facing a global extinction crisis. They are threatened by global warming, loss of habitat and the spreading incidence of the chytrid fungus. Species in the Bufonid genus are some of the most rapidly declining of any amphibian species. The implementation of captive insurance populations and reintroduction programs is imperitive to prevent further loss of species.

Amphibian reintroduction efforts need to maximize tadpole production in a small window of optimal release time. To do this, large numbers of tadpoles need to be produced. A common method to achieve this goal is to use hormone injections to stimulate the release of gametes and collect from individuals multiple times. However, little is known about the effect frequent hormone-induced spermiation (release of sperm) may have on the quantity and quality of sperm.

To test the effect of frequency of collection on sperm characteristics we compared the effect of four different treatments (twice a week, once a week, every other week, and every three weeks) on sperm concentration, motility, and forward progressive movement. 

We observed a significant decrease in sperm concentration and forward progressive movement in the most frequent treatment group. This group also experienced the greatest weight decrease over the study period. We also determined that the decrease was a result of the hormone treatments and not stress from the collection methodology. We concluded that management protocols should not induce spermiation more frequently than every other week. 

For my senior thesis I analyzed these results and wrote a manuscript on this research for my undergraduate research journal, The Beloit Biologist. A revised version of the article has been accepted for publication.