EurekAlert: UBC researcher gives first-ever estimate of worldwide fish biomass and impact on climate change Are there really plenty of fish in the sea? University of British Columbia fisheries researcher Villy Christensen gives the first-ever estimate of total fish biomass in our oceans: Two billion tonnes. And fish play a previously unrecognized but significant role in mitigating climate change by maintaining the delicate pH balance of the oceans, according to a study published in …