Conservation and Management of Crayfishes: Lessons from Pennsylvania

Abstract

North America's crayfish fauna is diverse, ecologically important, and highly threatened. Unfortunately, up‐to‐date information is scarce, hindering conservation and management efforts. In Pennsylvania and nearby states, recent efforts allowed us to determine the conservation status of several native crayfishes and develop management strategies for those species. Due to rarity and proximity to urban centers and introduced (exotic) crayfishes, Cambarus (Puncticambarus) sp., an undescribed member of the Cambarus acuminatus complex, is critically imperiled in Pennsylvania and possibly range‐wide. Orconectes limosus is more widespread; however, recent population losses have been substantial, especially in Pennsylvania, and northern Maryland, where its range has declined (retreated eastward) by greater than 200 km. Introduced congeners likely played a major role in those losses. Although extirpated from some areas, Cambarus bartonii bartonii remains widespread and is not an immediate conservation concern. In light of these findings, the role of barriers (e.g., dams), environmental protection, educational programs, and regulations in preventing crayfish invasions and conserving native crayfishes is discussed, and management initiatives centered on those factors are presented. The need for methods to eliminate exotics and monitor natives is highlighted. Although tailored to a specific regional fauna, these ideas have broad applicability and would benefit many North American crayfishes.

Examining One State's Regulation Development Process to Manage Alien Crayfish Introductions

“…Education alone is insufficient as a natural resources management tool for changing human behavior (Baruch-Mordo et al 2011), especially with regard to preventing aquatic alien species introductions (Rothlisberger et al 2010). Yet, education targeting stakeholders, policy makers, and potential introduction pathways, combined with regulation, is a necessary component of effective management of invasive crayfish problems (Lodge et al 2000b;García-Llorente et al 2008;Lieb et al 2011). Thus, MDC enforcement officers adopted a policy of educating (rather than penalizing) bait shop owners during the first year following the regulation change.…”

“…Some fisheries scientists have called for regional or total U.S. bans on sales of live crayfishes as bait (Lodge et al 2000b;Lieb et al 2011;Martinez 2012); many states and provinces have already implemented or are considering regulations on the sale or import of live crayfishes for bait or other uses (DiStefano et al 2009;Larson and Olden 2011;Kilian et al 2012). Effects of alien crayfish invasions to Missouri fisheries are largely unstudied, but recent work documented population declines of at least six native crayfish species associated with 31 suspected introductions and subsequent range expansions of invasive crayfishes.…”

Full Issue PDF, Volume 41, Issue 12

“…Some fisheries scientists have called for regional or total U.S. bans on sales of live crayfishes as bait (Lodge et al 2000b;Lieb et al 2011;Martinez 2012); many states and provinces have already implemented or are considering regulations on the sale or import of live crayfishes for bait or other uses (DiStefano et al 2009;Larson and Olden 2011;Kilian et al 2012). Effects of alien crayfish invasions to Missouri fisheries are largely unstudied, but recent work (DiStefano et al 2015) documented population declines of at least six native crayfish species associated with 31 suspected introductions and subsequent range expansions of invasive crayfishes.…”

Invasive rusty crayfish (Faxonius rusticus) are diurnally more exposed than an imperiled native congener

“…Non-native crayfish have been introduced into freshwater ecosystems worldwide and can become invasive, resulting in negative consequences for native organisms (Holdich 1988;Lodge et al 2000;Taylor et al 2007;Twardochleb, Olden, and Larson 2013). Establishment of invasive crayfish within freshwater ecosystems typically coincides with the extirpation of native crayfish species (Bouchard et al 2007;Lieb et al 2011a;Lodge et al 2000;Taylor et al 2007). Invasive crayfish threaten native crayfish populations by disease transmission, hybridization, and ecological displacement as a result of competition (Holdich 1988;Lieb et al 2011a;Lodge et al 2000;Olden et al 2006;Pintor and Sih 2009;Zuber et al 2012).…”