In the early 1800s, the ocean around New Zealand contained about 27,000 southern right whales – that is, about 30 times more than today. This has been revealed in one of several startling reconstructions of ocean life in olden days and presented at the Census of Marine Life conference on May 26-28, 2009, in Denmark.
According to British researchers, while large pods of blue whales and orcas, blue sharks and thresher sharks were plentiful in the waters off Cornwall, England, herds of harbour porpoise chased fish upriver, and dolphins played in waters inshore.
Census researchers used diverse sources like old ship-logs, literary texts, tax accounts, newly translated legal documents and even mounted trophies in order to put together images of fish of great sizes, abundance and distribution that would be hard to believe in our times.
The researchers are also documenting the timelines over which the abundant marine-life populations got depleted.
Census scientists say that the size of freshwater-fish caught by Europeans started shrinking in medieval times. This, they believe, could have been the result of a shift from eating locally caught freshwater-fish to marine-fish species (around 1000 AD). And, this theory is consistent with analyses of scientifically dated fish remains and historical data from England and north-western Europe.
A study conducted by Maria Lucia De Nicolo, of the Università di Bologna in Italy, has established that new fishing boats and equipment invented in the 1500s had led to a shift from coastal fishing to deep-sea fishing. The real revolution in marine fishing, according to her, occurred in the mid-1600s, when pairs of boats began to be used to drag fishing net.