Gordon Copp on the Evolving Concept of Non-Native Fish
Emerging Research Fronts Commentary, August 2011
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For example, one of conferences attended by CLG members resulted in a review paper in which a quantitative model was proposed by CLG partners for predicting the invasiveness of pumpkinseed in Europe based on their juvenile growth and age at maturity. The research is an interface between applied and theoretical science in the area of fish biology and fisheries management, but with direct implications for policy makers and legislators.
Probably the main challenge being faced is funding: with the ever-increasing number of non-native species, we always have many more topics to study than we have time and money to address. In particular, it is difficult to predict how fishes will respond to future climatic conditions, and it is precisely this task that governments are asking us to undertake. Fishes are notorious for doing the unexpected, which makes horizon-scanning difficult.
Where do you see your research leading in the future?
Many of the individuals involved in this publication continue to work on non-native fishes, including population ecology, mechanisms of spread, traits that make them successful, assessments of their impacts, genetic aspects as well as providing advice to policy makers. Although the funding for the CLG network ended in 2004, the network still functions through bi-lateral arrangements between CLG members using their national and international funding sources.
For example, CLG members and their associated contacts are currently collecting pumpkinseed tissue samples from around Europe and North America for use in a study initially discussed when the "To be or not to be" paper was being formulated — a comprehensive examination of the genetics of this successful invader of European waters. The collaborative research has expanded well beyond pumpkinseed, though some of us still work on this species, and authors of this paper have been focusing on other important invaders such as topmouth gudgeon (Pseudorasbora parva), the Ponto-Caspian gobies and the Amur sleeper (Perccottus glenii).
Figure 1:
Quantitative biological model, based on mean age at
maturity and juvenile growth (i.e. total length at age 2), for predicting
the invasiveness of introduced pumpkinseed populations in Europe (redrawn
and updated from Copp & Fox, 2007).
Cited Reference: Copp, G.H. & Fox, M.G. 2007. Growth and life history
traits of introduced pumpkinseed (Lepomis
gibbosus) in Europe, and the relevance to invasiveness potential. pp.
289–306 In: Freshwater Bioinvaders: Profiles,
Distribution, and Threats (F. Gherardi ed.), Springer, Berlin.
A major issue will be the development of policy, research and development to respond to the challenges of non-native species—both in relation to climate change, the prioritization of risks and the associated procedures for containment and control.
Do you foresee any social or political implications for your research?
This article revealed that although all countries considered in the review have legislation to deal with issues associated with non-native fish introductions, only one of them (the UK) had established effective regulatory mechanisms. Hopefully, this article has influenced, or contributed to, the development of policies and research programs for invasive species, including fishes, in some of the countries. Indeed, the "To be or not to be" paper was intended to provide governments with an objective, unbiased and evidence-based review of patterns in non-native freshwater fish introductions so that these can be used to help develop informed advice and to influence policy.
Non-native species issues tend to be highly contentious, not only amongst the various stakeholders but also amongst scientists. For example, one paper produced by one of the "To be or not to be" co-authors evoked a series of published essays in which the issues were debated.
The intensity of non-native species debates varies across Europe and North America, as do concerns about the impacts of invasive species, with some areas being particularly troubled by non-native species due to high species endemism (Iberian Peninsula) or effects on ecosystem function and services (e.g. the Great Lakes). Some invasions are occurring through natural species expansion, such as the Ponto-Caspian gobies up the River Danube and down the River Rhine, however these have been possible mainly due to human activities (e.g. reservoir and canal/lock construction) and in part to changes in climatic conditions.
Central to these debates is the perception of risks, of relative impacts and of ecosystem value. Even amongst researchers, the risks posed by the same species will be perceived differently, the perceived magnitude of the likely impacts will also vary, and both of these will be influenced by one's perception of what value to place on nature.
For example, how do we treat a species that is disappearing (i.e. threatened) in its native range but is invasive (i.e. a potential pest) outside its native range? Do we protect our natural resources (i.e. natural ecosystem integrity) and eradicate or control the species, or do we protect the species from extinction, as the introduced range may be the only location(s) where the species is likely to persist for future generations? These are difficult questions that are being faced by society in general, and scientists and governments in particular. "To be or not to be a non-native," that is the question?.
Prof. Gordon H. Copp
Salmon & Freshwater Team
Centre for Environment, Fisheries & Aquaculture Science (Cefas)
Lowestoft, Suffolk, UK
Visiting Professor
Centre for Conservation Ecology & Environmental Change
Bournemouth University
Poole, Dorset, UK
Adjunct Professor
Environmental & Life Sciences Graduate Programme
Trent University
Peterborough, Ontario, Canada
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KEYWORDS: NON-NATIVE, ALIEN, FRESHWATER FISH, INTRODUCTION, DISPERSAL, EUROPE, NORTH AMERICA, NEOGOBIUS MELANOSTOMUS, PSEUDORASBORA PARVA, RAINBOW TROUT, ROUND GOBY, BIOLOGICAL INVASIONS, BRITISH COLUMBIA, ATLANTIC SALMON, UNITED STATES, CARP.