Conflicts between Native Fish and Nonnative Sport Fish Management in the Southwestern United States

Abstract

The ubiquitous presence of nonnative fishes, both sport and nongame, within waters of the southwestern United States is the foremost factor preventing immediate conservation and recovery of imperiled native fishes. We present evidence that the two fishery types cannot be co‐managed in sympatry if natives are to persist. A dual responsibility of federal and state fish and wildlife agencies to manage both fishery types creates internal conflicts that typically are resolved in favor of nonnative sport fisheries, despite existence of the Endangered Species Act. We advocate designation of watersheds to be managed exclusively for one fishery type or the other, and implementation of an aggressive program to eliminate nonnatives in native‐designated waters and protect against their reinvasion. To mitigate institutional conflicts, agency infrastructures should be segregated to promote independent management of native fisheries and introduced sport fisheries. This approach can fulfill mandates of both the Endangered Species Act and the 1996 Fish and Wildlife Service policy on recreational fishing.

Stocking of Endangered Razorback Suckers in the Lower Colorado River Basin over Three Decades: 1974–2004

“…Minimal natural recruitment has been observed in Lake Mead, but it is the exception to the norm (Abate et al 2002;Albrecht and Holden 2005). Considering that poor survival of repatriated fish probably is indicative of the losing battle between imperiled native fishes and introduced predators, the future management of natives undoubtedly lies in the creation of segregated habitats (Clarkson et al 2005). Such habitats are both presently available (but underutilized) and easily created and managed.…”

“…Such habitats are both presently available (but underutilized) and easily created and managed. A plan for the design, creation, and management of predator-free habitats for native fish is presented by Minckley et al (2003) and reiterated in the Big-River Fishes Management Plan (USFWS 2004), but the mechanisms have not been achievable due to inter-and intra-agency conflicts regarding the management and disposition of nonnative sport fishes and native species (see also Clarkson et al 2005). However, implementation of the Multi-Species Conservation Plan, a 50-year, $626-million conservation initiative enacted in April 2005, will presumably alleviate many of these roadblocks.…”

“…The razorback sucker's decline is attributed to habitat loss and modification in concert with predation by introduced, nonnative fishes (Tyus and Saunders 2000;Clarkson et al 2005;. Although adults spawn annually and produce offspring in the anthropogenically modified habitats (Marsh and Langhorst 1988;Holden et al 2001a;, early life stages are rapidly consumed by introduced predators, curtailing recruitment to adulthood (Minckley and Deacon 1968;Miller 1972;Johnson and Rinne 1982;Medel-Ulmer 1983;Minckley 1983).…”

Razorback sucker recruitment in Lake Mead, Nevada–Arizona, why here?

“…One major factor causing the decline of razorback sucker and other large-river fishes has been the construction of mainstem dams and the resultant cool tailwaters and reservoir habitats that replaced a once warm, riverine environment (Holden and Stalnaker 1975, Joseph et al 1977, Wick et al 1982, Minckley et al 1991. Competition and predation from nonnative fishes that are successfully established in the Colorado River and its reservoirs have also contributed to their decline (Minckley et al 1991, Mueller and Marsh 2002, Clarkson et al 2005, Mueller 2005). …”

Measuring ecosystem degradation through half a century of fish species introductions and extirpations in a large isolated lake

“…In addition to extinctions, human-induced exotic species introductions are also listed as one of the most detrimental anthropogenic activities (Dudgeon et al, 2006;Sala et al, 2000). Exotic species can threaten aquatic biodiversity and influence ecological process (Clarkson et al, 2005;Jeschke et al, 2014;Volta et al, 2013). There is thereby a pressing need to manage the use of biodiversity and resources, and to conserve and restore ecological processes.…”