How Much kelp do sea urchins eat?

Answer 1

yes

Answer 2

Sea urchins eat the holdfast, the part of the kelp that holds the kelp to the seabed. Once the holdfast is consumed, there is nothing to anchor the kelp, which will then float to the ocean's surface and, eventually, die.

Sea otters are some of the most significant natural predators of sea urchins. But due to the depletion of sea otter populations by excessive hunting in the past couple centuries, there have been too few otters to control the levels of urchin population. Urchins have therefore been eating the kelp faster than the kelp can reproduce, in some locations. Many areas that once had large kelp forests have been eaten away until nothing is left, leaving behind regions known as "urchin barrens". This proves detrimental not only for the kelp, but also the multitudes of animals, ranging from other invertebrates to fish to whales, that depend on the kelp forest in one way or another as an integral part of their habitat.