Limited movement of freshwater mussel fish hosts in a southern US river

作者：Irmscher Pascal^*; Vaughn Caryn C

来源：Hydrobiologia, 2015, 757(1): 223-233.

DOI：10.1007/s10750-015-2254-9

• Upstream compensatory movement
• Downstream drift dispersal
• Turbulent flow
• Patchiness
• Juvenile unionid mussels
• Host fish species

Organisms that live in flowing water need to compensate for downstream displacement. Mobile animals can compensate for displacement by actively swimming or crawling upstream, while sedentary animals need other means to retain their position. Freshwater mussels (Bivalvia, Unionidae) have limited movement as adults, and juveniles drift downstream after excystment from their host. Mussel larvae are ectoparasites on fish, and it has been assumed that fish move larvae back upstream; however, this has not been tested experimentally. We hypothesized that fish served as dispersal agents, and that fish movement had an upstream bias to compensate for displacement of mussels by drift. We conducted a mark-and-recapture study of host fish in four 100-m reaches of the Little River, OK, USA, in the summer of 2011. Our study took place during a drought, and overall captures decreased with decreasing discharge, likely because fish moved out of their home ranges into deeper pools. Most recaptured fishes were centrarchids, and most recaptures occurred within 20 m of initial capture transects. While most moved < 20 m, when fish did move to longer distances, they moved more upstream than downstream, allowing mussels to compensate for displacement.

• 出版日期2015-9