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

Abstract

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.

Isotope geochemistry reveals ontogeny of dispersal and exchange between main‐river and tributary habitats in smallmouth bass Micropterus dolomieu

“…The species distribution is expected to expand further as climate change alters the thermal regimes of coldwater habitats and opens them to colonization by cool‐water fishes (Shuter & Post, ; Chu et al , ). Micropterus dolomieu play an important role in shaping freshwater communities as top predators with a broad dietary niche (MacRae & Jackson, ), as intermediary hosts and dispersal vectors for aquatic invertebrate species (Kappes & Haase, ; Irmscher & Vaughn, ), and through reproductive facilitation for brood parasitic species (Goff, ). There is considerable conservation concern regarding the effects invading M. dolomieu will have on the biotic communities in these systems (Iguchi et al , ; Vander Zanden et al , ; Carey et al , ).…”

Population Genetics of a Common Freshwater Mussel, Amblema plicata, in a Southern U.S. River

“…Gene flow among mussel beds requires sufficient flow for the movement of fish hosts, juveniles, sperm, and/or unattached glochidia. Irmscher and Vaughn (2015) found that the movement of fish hosts in the Little River was restricted during droughts. Thus, lowwater conditions during droughts may restrict gene flow between upstream and downstream populations or decrease upstream population sizes and exacerbate genetic drift.…”

Movement and Diel Habitat Use of Juvenile Neosho Smallmouth Bass in an Ozark Stream

“…Similarly, higher flows promoted longitudinal movements and refuge use by adult Smallmouth Bass (Todd and Rabeni ), and drought conditions greatly restricted these movements (Hafs et al. ; Irmscher and Vaughn ). Although discharge during our study period fluctuated little, we would hypothesize that discharge is important for movement in other water‐year types given its influence on habitat connectivity and water depth.…”

“…Smallmouth Bass movements are especially limited under summer drought conditions (Hafs et al. ; Irmscher and Vaughn ). Home range size is typically smaller in streams than in oligotrophic lakes (Ridgway and Shuter ).…”