Ocean historians affiliated with the Census of Marine Life have painted the first detailed portrait of a burst of fishing from 1900 to 1950 that preceded the collapse of once abundant bluefin tuna populations off the coast of northern Europe.
The chronicle of decimation of the bluefin tuna population in the North Atlantic is being published as other affiliated researchers release the latest results of modern electronic fish tagging efforts off Ireland and in the Gulf of Mexico, revealing remarkable migrations and life-cycle secrets of the declining species.
Tuna Past: Case of the Disappearing Bluefins
Dusting off sales records, fishery yearbooks and other sources, researchers Brian R. MacKenzie of the Technical University of Denmark and the late Ransom Myers of Canadas Dalhousie University show majestic bluefins teemed in northern European waters (North Sea, Norwegian Sea, Skaggerak, Kattegat, and Oresund ) for a few months each summer until an industrialized fishery geared up in the 1920s and literally filled the floors of European market halls with them.
The research, to appear in a special edition of the peer-reviewed journal Fisheries Research, shows that generations ago Atlantic bluefins typically arrived in the northern waters by the thousands in late June and departed by October at the latest, their foraging travels likely related to seasonal warming.
Danish fishers from the mid-1800s welcomed the bluefin tuna as a partner in the catch of the garfish species. The bluefins pursued garfish into nets that fishers set close to shore.
Before World War I, the bluefins were rarely captured and even coastal sightings were exciting events. One measuring 2.7 meters (almost 9 feet) washed up on a German shore in 1903. Those captured in the 1920s ranged from 40 kilograms to giants of 700 kilograms, with an average weight of 50 to 100 kilograms.