Sea otter predation on sea urchins prevents urchin barrens and maintains kelp forests. Understanding this trophic cascade illustrates how individual welfare connects to ecosystem health.
Sea otter predation on urchins illustrates that individual animal welfare and ecosystem function are deeply connected. In areas without sea otters, urchin populations grow unchecked, consuming kelp until nothing remains — creating urchin barrens where many species cannot survive. The welfare of fish, invertebrates, and marine mammals in kelp-dependent ecosystems depends indirectly on the presence of sea otters controlling urchin populations. This trophic cascade means that protecting sea otter welfare and populations provides welfare-positive effects for entire communities of species across the northeast Pacific.