People derive benefits from the seafood trade including food security, work and profits. As trade increases worldwide, the impacts of seafood production increase and are known to include overfishing and labour abuses in distant source areas, including the developing countries that provide most of the world’s seafood. Over the past decade, as demand for sustainably certified wild-caught seafood has begun to increase, seafood buyers, sellers and NGOs have taken voluntary measures to encourage sustainable seafood production, but without knowledge of the effects. What kinds of effects result from voluntary industry measures for sustainable seafood? Do the effects improve the social and environmental impacts of seafood production? Drawing from quality assurance methods and sustainability theory, seven voluntary measures taken in the private sector between 2008 and 2014 were evaluated for their effects against ten qualitative attributes said by sustainable seafood scholars to be necessary conditions for stewardship of common pool natural resources. Results indicate that the seven measures led to new forms of industry self-regulation that help to control some input variables of overfishing and to some increased compliance across supply chains. New empirical information was produced by the measures to determine where change is needed to solve conflicts and to reduce risks where they occur in seafood production. Some measures made access to resources more secure for business. Others provide diagnostic tools to reduce risks for overfishing, illegal fishing and forced and trafficked labour in seafood supply chains. Overall the measures helped the private sector to see and understand what is happening in source fisheries and to agree on ways to fix unsustainable practices.