John has been traveling and working in the North since 1962. There, he carried out a series of excavations at Bering Strait, serving for ten seasons as a member of an Eskimo whaling crew at Point Hope, Alaska. In the 1970s he descended the Tanana and Yukon rivers by canoe from Fairbanks to Nome and traveled along the coast from there to Barrow Strait in arctic Canada. Later, he twice traversed the Northwest Passage by boat.
John is the author of a number of fascinating books, monographs, and articles, including Arctic Passages: A Unique Small Boat Voyage through the Great Northern Waterway (1991, 1992), Arctic Discoveries: Images from Voyages of Four Decades in the North (2000), High Latitude, North Atlantic: 30,000 Miles through Cold Seas and History (2003), and the award-winning Whales, Ice and Men: The History of Whaling in the Western Arctic (1986, 1995).
My own work with John goes back more than three decades, when the International Whaling Commission’s Scientific Committee recommended a moratorium on the Eskimo harvest of bowhead whales (Balaena mysticetus) in the Bering, Chukchi, and Beaufort seas because of a high (and then increasing) strike rate, combined with imprecise estimates that the bowhead population was low.
As a result of this controversy, John invited me to team up with him to examine all existing logbook and journal records of the historical commercial whaling industry to estimate both the size of the bowhead population that existed at the beginning of the commercial harvest and the size of the harvest over time.
As part of the study, we digitized all the daily records, which provide more than 65,000 days of observation between 1849 and 1915. Logbooks exist for more than 500 voyages, 19% of all the voyages ever made to hunt the bowhead whale. These ship logbooks provided an incredible amount of unique information. Everyday an officer of a ship wrote in the logbook what the sea and weather conditions were and information about marine mammals seen, those chased, and caught.
Then, with the growing concern about the decline in Arctic sea ice coverage, measured by modern satellite remote sensing, the logbooks provided an additional insight. Each day, the logbooks record whether the whalers saw and/or were within sea ice. We cooperated with two sea ice experts of the University of Alaska, Andrew R Mahoney and Hajo Eicken, and an expert on some advanced data analysis methods, Robert A. Nisbet, and showed how Arctic sea ice extent in the Bering, Chukchi, and Beaufort seas from 1850 to 1914 compared with modern sea ice extent.
Records from May indicate that end-of-winter sea-ice extent in the Bering Sea during the mid 19th century closely resembled that in the 1972 – 82 data. However, the historical data reveal that sea ice was more extensive during summer, with the greatest difference occurring in July. This pattern indicates a later and more rapid seasonal retreat. These conclusions highlight the value of historical data, which we have far from exhausted in this study.
For a more detailed look a the sea ice data, please go to NatureStudy.org.
For more information about John Bockstoce, visit http://www.johnbockstoce.com/