Katmai was declared a national monument in 1918 to preserve the living laboratory of its cataclysmic 1912 volcanic eruption, particularly the Valley of 10,000 Smokes. Since then, most surface geothermal features have cooled, but protecting brown bears has become an equally compelling charge. To protect these magnificent animals and varied habitat, the boundaries were extended over the years, and in 1980 the area was designated a national park and preserve. Katmai looms so vast that the bulk of it eludes all but a few persistent visitors. Other lodges, rivers and streams are accessible by float plane and offer a glimpse of the unseen Katmai, beyond the usual experiences of fishing Brooks River, walking up to Brooks Falls, and riding the bus out to the Valley of 10,000 Smokes.
Katmai National Park's awe-inspiring natural powers confront us most visibly in its brown bears. In summer, North America's largest land predators gather along streams to feast on salmon runs, building weight from this wealth of protein and fat, preparing for the long winter ahead. Alaska's brown bears and grizzlies are now considered one species. People commonly consider grizzlies to be those that live 100 miles and more inland. Browns are bigger than grizzlies thanks to their rich diet of fish. Kodiak brown bears are a different subspecies that is geographically isolated on Kodiak Island in the Gulf of Alaska. Mature male bears in Katmai may weigh up to 900 pounds. Mating occurs from May to mid-July, with the cubs born in dens in mid-winter. Up to four cubs may be born, at a mere pound each. Cubs stay with the mother for two years, during which time she does not reproduce. The interval between litters is usually at least three years. Brown bears dig a new den each year, entering it in November and emerging in April. About half of their lifetimes is spent in their dens. Because each bear is an individual, no one can predict exactly how a given bear will act in a given situation. These awe-inspiring bears symbolize the wildness of Katmai today.
Besides brown bear, Katmai National Park provides a protected home to moose, caribou, red fox, wolf, lynx, wolverine, river otter, mink, marten, weasel, porcupine, snowshoe hare, red squirrel, and beaver. Marine mammals include; sea lions, sea otters, and hair seals. Beluga, killer, and gray whales can also be seen along the coast of the park.
A predictable eruption occurs at Katmai National Park and Preserve annually as salmon burst from the northern Pacific Ocean and into park waters. Sockeye (also known as red) salmon return from the ocean, where they have spent two or three years. Navigating first across the open ocean, and then up rivers, lakes, and streams, they return to the headwater gravel beds of their birth to deposit their own young before dying. Their size, averaging 5 to 7 pounds, varies proportionally to how long they spend feeding at sea.
The salmon run begins here in mid to late June. By July's end a million fish may have moved from Bristol Bay into the Naknek system of lakes and rivers. Salmon stop feeding upon entering freshwater, and physiological changes lead to the distinctive red color, humped back, and elongated jaw they develop during spawning. The salmon spawn during August, September, and October. Stream bottoms must have the correct texture of loose gravel for the eggs to develop. The stream must flow freely through winter to aerate the eggs. By spring the young fish that have just hatched, called 'fry' or 'juveniles', emerge from the gravels and migrate into the larger lakes, living there two years. The salmon then migrate to sea, returning in two or three years to spawn and begin the cycle once again. Salmon provide food for the brown bears, bald eagles, rainbow trout, and directly or indirectly for the other creatures that forage along these streams. They also have been important to Katmai people for several thousand years, and commercial fishing, outside the park, remains the mainstay of today's local economy.