The northwest Atlantic cod has been regarded as heavily overfished throughout its range, resulting in a crash in the fishery in the United States and Canada during the early 1990s. Newfoundland's northern cod fishery can be traced back to the 16th century. "On average, about 300,000 tonnes of cod was landed annually until the 1960s, when advances in technology enabled factory trawlers, many of them foreign, to take larger catches. By 1968, landings for the fish peaked at 800,000 tonnes before a gradual decline set in. With the reopening of the limited cod fisheries last year, nearly 2,700 tonnes of cod were hauled in. Today, it's estimated that offshore cod stocks are at one per cent of what they were in 1977" [1]. Technologies that contributed to the collapse of Atlantic Cod include engine power vessels and frozen food compartments aboard ships. Engine power vessels had larger nets, larger engines, and better navigation. The capacity to catch fish became limitless. In addition, sonar technology gave an edge to catching and detecting fish. Sonar was originally developed during WWII to locate enemy submarines, but was later applied to locating schools of fish. These new technologies, as well as bottom-trawlers that destroyed entire ecosystems, contributed to the collapse of Atlantic Cod. They were vastly different from old techniques used, such as hand lines and long lines.[5] The fishery has yet to recover, and may not recover at all because of a possibly stable change in the food chain. Atlantic cod was a top-tier predator, along with haddock, flounder and hake, feeding upon smaller prey such as herring, capelin, shrimp and snow crab.[4] With the large predatory fish removed, their prey has had a population explosion and have become the top predators.