Juvenile Drift of Round Gobies (Neogobius melanostomus) in the French Creek Watershed as a Means of Range Expansion

Abstract:

A newly introduced invasive fish, the round goby (Neogobius melanostomus), was discovered in the French Creek watershed in 2014 and is threatening the unique biodiversity within the stream system. Successful management strategies of this invasive species depend on accurate information about many life history strategies, including dispersal mechanisms. Most research on round goby natural dispersal within the French Creek watershed focuses on adults, but juvenile drift may be a form of downstream dispersal in French Creek that has not been examined. The objective of this study was firstly, to document whether juveniles were utilizing drift as a means of range expansion, and secondly, to describe abiotic factors correlating with drift density. Drifting larval and juvenile fishes were collected by placing drift nets across stream transects twice a month from June to August 2021 in the French Creek watershed at an invaded site, the last known location of the invasion front, and an uninvaded site.  Drift nets were set an hour before sunset and sampled every hour for 5 hours.  Preliminary results show drifting juvenile round gobies are present at the invaded site. Understanding the patterns of round goby larval drift is necessary to inform management strategies that limit the dispersal of round gobies in the French Creek watershed and beyond.