A Practical Approach for Assessing Ecological Risks Associated with Fish Stocking Programs

As wild fish populations continue to decline, fisheries managers are increasingly concerned about how hatchery operations might be contributing to declines of highly valued wild populations. Ecological risk assessments can provide decision makers with critical information about potential effects of stocking. In this paper we describe a practical approach for assessing ecological risks to select nontarget taxa (NTT) associated with fish stocking programs. This approach requires the completion of five tasks: (1) Determine acceptable impacts to NTT (e.g., impact of 10% to a species distribution, abundance, or size structure); (2) determine potential spatial‐temporal overlap of NTT life stages with target taxon; (3) determine potential strong ecological interactions; (4) determine ecological risk; and (5) determine scientific uncertainty of ecological risk assessment. These tasks are accomplished by analyzing information gathered from scientists, managers, and policy makers. The result of the assessment is a listing of the ecological risks and associated uncertainties of failing to meet a stated objective for a variety of NTT. We also describe a decision matrix that prescribes various levels of uncertainty resolution, risk minimization strategies, risk containment monitoring, and stocking proposal implementation. Prescriptions reflect the amount of ecological risk and scientific uncertainty. Application of ecological risk assessment concepts to hatchery stocking decisions allows for a balanced approach when evaluating the benefits of hatchery stocking relative to ecological costs to nontarget populations and the economic costs of risk management.