Researchers for the History of Marine Animal Populations used old ship's logs, tax accounts, ancient texts, and monastery archives to create an overview of whales, fish and other sea creature populations. Research is part of the ten-year Census of Marine Life to be released in 2010.

Records showed New Zealand southern right whales numbered between 22,000 and 32,000 in the early 1800s but were hunted to only 25 reproductive females by 1925. Waters of the English Isles were once home to orca, blue whales, porpoise, dolphins, and blue and thresher sharks.

Historic data presented at the recent "Oceans Past II" conference in Vancouver, Canada will be used to assess environmental change in the oceans and help depleted populations recover.