Fish and mussels: Importance of fish for freshwater mussel conservation

Abstract

Co‐extinctions are increasingly recognized as one of the major processes leading to the global biodiversity crisis, but there is still limited scientific evidence on the magnitude of potential impacts and causal mechanisms responsible for the decline of affiliate (dependent) species. Freshwater mussels (Bivalvia, Unionida), one of the most threatened faunal groups on Earth, need to pass through a parasitic larval (glochidia) phase using fishes as hosts to complete their life cycle. Here, we provide a synthesis of published evidence on the fish–mussel relationship to explore possible patterns in co‐extinction risk and discuss the main threats affecting this interaction. We retrieved 205 publications until December 2015, most of which were performed in North America, completed under laboratory conditions and were aimed at characterizing the life cycle and/or determining the suitable fish hosts for freshwater mussels. Mussel species were reported to infest between one and 53 fish species, with some fish families (e.g., Cyprinidae and Percidae) being used more often as hosts than others. No relationship was found between the breadth of host use and the extinction risk of freshwater mussels. Very few studies focused on threats affecting the fish–mussel relationship, a knowledge gap that may impair the application of future conservation measures. Here, we identify a variety of threats that may negatively affect fish species, document and discuss the concomitant impacts on freshwater mussels, and suggest directions for future studies.

Modelling the invasion history of Sinanodonta woodiana in Europe: Tracking the routes of a sedentary aquatic invader with mobile parasitic larvae

“…That period is sufficient for successful long‐distance dispersal associated with the trade in freshwater fishes for aquaculture and angling purposes across Europe (Litvak & Mandrak, ). While many unionid mussel species are host specialists (Modesto et al., ), S. woodiana has an extremely extensive host range and can utilize all European freshwater fish species hitherto tested (Douda et al., , ). This feature is not unique to invasive S. woodiana populations, because S. woodiana also utilizes an exceptionally broad range of host species in its native range (Douda et al., ; Dudgeon & Morton, ).…”

Developing a standard approach for monitoring freshwater pearl mussel (Margaritifera margaritifera) populations in European rivers

“…The recruitment of freshwater pearl mussels is closely linked to healthy populations of host fish, onto which glochidial larvae attach, that act as vectors for dispersal and as a source of nutrients (Denic, Taeubert, & Geist, ; Modesto et al, ). In Europe, M. margaritifera larvae can only metamorphose successfully on Atlantic salmon ( Salmo salar Linnaeus, 1758) and native brown trout ( Salmo trutta Linnaeus, 1758), with the brown trout being the exclusive host in most Central European populations (Geist, Porkka, & Kuehn, ; Hastie & Young, ; Taeubert & Geist, ).…”

An unexpected host for the endangered giant freshwater pearl mussel Margaritifera auricularia (Spengler, 1793) as a conservation tool

“…Thus, the earlier reproductive period of M. auricularia in relation to other margaritiferids, which is also driven by temperature (Soler, Wantzen, et al, ), may be linked to the arrival of anadromous adults at their spawning grounds. Nevertheless, hosts at the juvenile stage appear to be most highly infested with freshwater mussel glochidia (Karna & Millemann, ; Modesto et al, ; Young & Williams, ). Given the large number of ammocoetes present during the reproductive period of M. auricularia , it would be expected that they would also be infested by glochidia.…”