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Socio-Economic Impact of the Presence of Asian carp in the Great Lakes Basin

Socio-Economic Impact of the Presence of Asian carp in the Great Lakes Basin

Socio-Economic Impact of the Presence of Asian carp in the Great Lakes Basin (PDF, 634 KB)

Prepared by
Salim Hayder, Ph.D.

Edited by
Debra Beauchamp

Fisheries and Oceans Canada, Policy and Economics
501 University Crescent, Winnipeg, Manitoba R3T 2N6

Table of Contents

Chapter 6: Scenario Based on Biological Risk Assessment

Historically, AIS have caused extensive damage to Great Lakes ecosystems, however it is difficult to precisely measure AIS populations and calculate their impacts with a high degree of certainty (Jude et al., 2004). There are some critical factors for determining the magnitude of AIS threats such as the species’ reproduction rate, the species’ ability to compete with other species, the quantities of biomass the species consumes. Mere arrival of Asian carp does not in itself amount to a major ecological threat, as the species must also demonstrate its ability to establish a self-sustaining population. If Asian carp establishes a healthy population, it has a strong likelihood of harming native plant and animal life, due to its large size and its ability to consume large quantities of native species’ food sources (Lieberman, 1996).

For the AIS already established, the estimates of resulting damages could ideally be made from empirical analyses of key variables before and after the invasion, controlling all other factors that could simultaneously affect the response variables (Hoagland and Jin, 2006). For an invasive species like Asian carp that has yet to be introduced to the Great Lakes basin, such an analysis is not possible. It is therefore necessary to seek an alternative approach to the quantification of potential damages to the economy.

Ecologists are making significant efforts to identify concrete changes to the ecosystem caused by AIS. Assuming that only the current management measures are in place and all other things being equal, CEARA, DFO, evaluated the likelihood of arrival, survival, establishment, and spread of Bigheaded carps (Bighead and Silver carps) in the Great Lakes basin, and the magnitude of the ecological consequences, based on a qualitative scale and corresponding ranking of certainty, for up to 20 years and up to 50 years.Footnote 85

Following Mandrak, Cudmore and Chapman (2011), DFO (2012) divided the risk assessment process into three steps.Footnote 86

Firstly, it estimated the overall probability of an introduction of Asian carp (using estimates of likelihood of arrival, survival, establishment, and spread) as follows:

Probability of Introduction = Min [Max (Arrival, Spread), Survival, Establishment].

According to this formula, the overall probability of introduction was estimated sequentially by determining the highest ranking between ‘Overall Arrival and Spread’, incorporating the ranking to the ranks of ‘Survival and Establishment’, and finally taking the lowest rank of the three.

In the second step, the study determined the magnitude of the ecological consequences of an established population of Asian carp.

Finally, the results from step one and the magnitude of the ecological consequences were combined into a risk matrix to communicate an overall risk. Each lake was assessed at the 20 year and 50 year intervals.

The major findings of the ecological risk assessment of Bigheaded carps in connection to this socio-economic impact assessment study are as follows:

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