Cruising up the Wrangell Narrows south of Petersburg, the amount of bull kelp is remarkable. Long ropy strands hang from channel markers and pilings, and great wads are hung up on buoys and floats. Some structures are encased in massive tangles of the brown, tubular algae. My friend says the kelp growth was phenomenal during the warm sunny spring, and recent extreme tides have torn loose tremendous amounts from the anchoring rocks.
Although kelp is washing up on beaches, there is still plenty of kelp in kelp beds, dense patches of kelp that can span acres. These large patches are known as kelp forests and are important to aquatic life, providing food and shelter for fish, invertebrates and shellfish. Some fish, like herring, spawn in kelp beds. Kelp is a particularly important food for sea urchins. As we approach my friend's cabin in the narrows, seven harbor seals watch us from the fringes of a large kelp forest nearby. The reference to a forest is more apparent when the kelp is seen underwater. Anchored to the bottom, the long ropelike stipe rises 10 or 20 feet, held upright by a bulbous, air-filled bladder. Numerous kelp blades sprout from the bladder, ribbons three to six inches wide and more than a dozen feet long. The blades are like the leaves and that's where photosynthesis takes place. A kelp plant can be more than 100 feet long and can grow as much as three feet a day - one of the most remarkable growth rates in the plant kingdom.