Assessing Ecological and Evolutionary Consequences of Growth-Accelerated Genetically Engineered Fishes

Genetically engineered fish containing growth hormone (GH) transgenes have been synthesized for more than 25 years, now with modifications made in multiple aquacultured species. Despite significant improvements in production characteristics being realized, these fish have not yet entered commercial production. The very strong enhancement of growth rates that can arise from GH transgenesis in fish has generated public and scientific concern regarding ecological and food safety. Little ecological risk is anticipated from engineered strains kept in fully contained facilities, so the concern is largely directed toward the reliability of containment measures and determining whether robust ecological data, pertinent to nature, can be generated within research facilities to minimize uncertainty and allow reliable risk-assessment predictions. This article summarizes the growth, life history, and behavioral changes observed in GH-transgenic fish and discusses the environmental and evolutionary factors affecting the adaptation, plasticity, and fitness of transgenic fish and their potential consequences on natural ecosystems.