For many years nations had a three-mile territorial limit based on the distance a cannon ball could fly. Unfortunately, three miles was insufficient to protect U.S. fish. Japanese hunters and fishermen entered Alaskan waters by 1905. In June of that year the Revenue Cutter Perry found four Japanese schooners at Attu Island. They had 6,500 salmon on board, a partially-built floating trap and a shore camp.
In 1906 something horrible happened. Japanese hunters sneaked ashore on St. Paul Island one foggy day in July and began to poach seals. Unbeknownst to them, a small naval research station was also on the island. Some U.S. sailors tried to stop the poaching and events got crazy. Five Japanese were shot and killed, two were wounded and 12 more were captured. Those captured were convicted of poaching and sentenced to three months in jail at Valdez.
Japanese fishermen continued their near-shore sorties and their presence escalated until they entered the Bristol Bay area with an extensive fishing effort in 1936. That triggered a diplomatic crisis. By this time, foreign fleets were busy fishing on the high seas in both the Pacific and Atlantic oceans. This was very frustrating because many salmon stocks were already in a serious state of depletion. For instance, the largest harvest of Columbia River king salmon occurred over 50 years earlier, in 1883.
So you can see a little problem here. Foreign nations had the right to fish Alaska salmon as long as they stayed three miles out. The U.S. was reluctant to put resources into conservation when foreign fleets could so easily undermine their efforts.
Of course, America had timber, oil, coal, mining, farming, manufacturing, etc; which made its fisheries less important. In Iceland, however, fishing was premier. Following WWII, Iceland gained its independence from Denmark. It happened that England and several other countries were fishing cod close to Iceland. So in 1952 Iceland extended its territorial waters to four miles and in 1954 they extending the limit to 12 miles. England sent its navy to overrule the new limit and protect its fishing vessels, but Iceland outwitted them and the new standard stood.
After WWII the Japanese fishing fleet was again attracted to Alaskan waters. In March 1962 the “mothership” Banshu Maru 31 arrived off Kodiak seeking herring. Two 160-ton seiners were with her as well as two tenders and a smaller vessel. All told they had a crew of 200 men. On April 5 this fleet sailed into Cook Inlet, venturing at one point within a mile of shore. The next day they made sets in Shelikof Strait. Governor Egan directed Alaska enforcement agents to board the vessels and make arrests. Three crewmen were charged with fishing inside territorial waters without a license. However, the seizure was opposed by State Department officials who tried to stop the action. The Government of Japan protested and in May the State of Alaska quietly dropped charges.
This left Alaska in a poor position to stop the pillaging of her fish resources a mere three miles offshore, let alone the heavy fishing that was conducted on the high seas. Eventually, Congress got in gear. Led by Senator Magnuson, they passed the Fishery Conservation and Management Act in 1976, which declared a Fishery Conservation Zone that extended out to 200 miles offshore. In 1983 the U.S. adopted a 200-mile Exclusive Economic Zone (EEZ) by presidential proclamation, again reducing foreign fishing on U.S. stocks. And in 1988 the U.S. finally extended its territorial waters to a 12-mile limit.
It was during this era that pressure was brought on countries fishing on the high seas, well beyond the 200-mile EEZ. The United Nations Law of the Sea Convention was agreed upon in 1982 and through it, high seas driftnet fishing was banned. This was phased in as various countries took action on the ban, with the final legislation being ratified in 1994. Though there are still poachers, it was this treaty that finally eliminated the last legal interception of Alaskan salmon. The Magnuson-Stevens Fishery Conservation and Management Act is now the primary law governing fisheries management in the United States. But I want to stress that ultimately, an international treaty was necessary, and it was accomplished through the United Nations.
Since the UN treaty, conservation measures can be accomplished by fisheries management and the disciplines necessary to preserve or restore habitat.