The Offshore Mariculture Escape Genetic Assessment (OMEGA) model was built with the purpose of simulating escapes from an aquaculture farm system to a natural population, and estimating the potential effect of escaped fish surviving to encounter wild conspecifics. The model is intended to provide an assessment of risk associated with aquaculture operations and aid in the development of strategies to reduce adverse effects from escapes through generating escape scenarios based on the planned project, and parameterizing the model with aspects of the species’ biology, wild population dynamics, facets of the specific aquaculture operation, and by taking into account uncertainty around interactions between cultured and wild populations (Figure 1).
We provide a demonstration of OMEGA modeling and analyses based on the proposed Pacific Ocean AquaFarm’s plan to cultivate California Yellowtail (Seriola dorsalis) in a moored net pen system in Southern California. The goals of the analyses were to evaluate ways fish may escape from the net pen system, the magnitude and age distributions of escaped fish under different production and escape scenarios, and the potential consequences of escapes surviving in the wild. This analysis also focused on potential magnitude of escape levels and consequences related to within-population genetic diversity and reproductive fitness of California Yellowtail.
For this project, OMEGA simulations were conducted for a range of escape scenarios under full- and half-scale production alternatives. Escape scenarios included assumed ordinary operational levels of escape (leakage and episodic losses) and large-scale escapes from rare, but severe, infrastructure losses. A subset of these simulations and results will be presented here to demonstrate the use of OMEGA in project level analyses, and how these results inform NEPA regulatory considerations.