Recreational freshwater fishing drives non‐native aquatic species richness patterns at a continental scale

Abstract

AimMapping the geographic distribution of non-native aquatic species is a critically important precursor to understanding the anthropogenic and environmental factors that drive freshwater biological invasions. Such efforts are often limited to local scales and/or to single species, due to the challenges of data acquisition at larger scales. Here, we map the distribution of non-native freshwater species richness across the continental United States and investigate the role of human activity in driving macro-scale patterns of aquatic invasion.LocationThe continental United States.MethodsWe assembled maps of non-native aquatic species richness by compiling occurrence data on exotic animal and plant species from publicly accessible databases. Using a dasymetric model of human population density and a spatially explicit model of recreational freshwater fishing demand, we analysed the effect of these metrics of human influence on the degree of invasion at the watershed scale, while controlling for spatial and sampling bias. We also assessed the effects that a temporal mismatch between occurrence data (collected since 1815) and cross-sectional predictors (developed using 2010 data) may have on model fit.ResultsNon-native aquatic species richness exhibits a highly patchy distribution, with hotspots in the Northeast, Great Lakes, Florida, and human population centres on the Pacific coast. These richness patterns are correlated with population density, but are much more strongly predicted by patterns of recreational fishing demand. These relationships are strengthened by temporal matching of datasets and are robust to corrections for sampling effort.Main conclusionsDistributions of aquatic non-native species across the continental US are better predicted by freshwater recreational fishing than by human population density. This suggests that observed patterns are driven by a mechanistic link between recreational activity and aquatic non-native species richness and are not merely the outcome of sampling bias associated with human population density.

Pathways and places associated with nonindigenous aquatic species introductions in the Laurentian Great Lakes

“…We recognize that NAS richness patterns are potentially skewed by the search effort associated with specific areas (Hoffman et al, 2011). While we do not have independent effort estimates, a recent continental-scale analysis of NAS richness patterns that included the Great Lakes found that spatial "hotspots" in NAS richness were the same pre-and post-data rarefaction, suggesting an effort effect is not sufficiently large at this Great Lakes scale to alter interpretation of richness patterns (Davis & Darling, 2017).…”

Are well‐intended Buddhist practices an under‐appreciated threat to global aquatic biodiversity?

“…The ornamental fish trade is also a significant vector for invasive fishes (for example, Costa‐Pierce, ; Gozlan, Britton, Cowx, & Copp, ; Raghavan, Prasad, Anvar‐Ali, & Pereira, ). So too is fish stocking, both legal and illegal, in support of recreational angling (Davis & Darling, ), as well as accidental releases, such as bait releases, aquaculture escapes, or ballast water transport (Gupta & Everard, ; Lintermans, ). Notwithstanding the life‐history traits of individual species favouring the establishment of new populations, propagule pressure (i.e.…”

Recreational angling as a pathway for invasive non-native species spread: awareness of biosecurity and the risk of long distance movement into Great Britain

“…A few studies have been undertaken to investigate the role of angling in the secondary dispersal of INNS between water bodies (Gates et al 2009;Anderson et al 2014), and others have reported the potential for INNS introduction and spread from the use of live bait by anglers (Keller et al 2007;Kilian et al 2012;Drake and Mandrak 2014;Cerri et al 2017). In North America, higher numbers of non-native species have also been found to coincide with areas of greater recreational fishing demand (Davis and Darling 2017). However, there have been limited, if any, studies undertaken to investigate the potential for long-distance jump dispersal of INNS between continents/countries on damp angling equipment.…”