Therefore oxygen concentration tends to be higher in this region which means regeneration of nutrients is fast. Smaller fish species prefer to use kelp as a hiding ground to avoid predators instead of swimming in the open ocean. Sea otter The sea otter, Enhydra lutris , belongs in the class Mammalia and it is the only true aquatic mammal species in the otter family, which lives exclusively in the sea. Sea otters tend to form groups called rafts or pods, ranging from a few individuals to several thousands depending on the abundance of food resource. Diet of sea otters depends on the abundance of the prey species.
Sea otters tend to be size-selective feeders, feeding on the largest organisms in the area first.
The sea urchins, Strongylocentrotus spp. , belong in the class Echinoidea of the phylum Echinodermata. These radially symmetrical invertebrates are armed with long, movable spines which prevent consumption by predators. These adaptations have made the sea urchins to be one of the most successful competitors in the intertidal community. Their sizes range from 1 to 12 cm in diametre. Movement of sea urchins is related to their feeding activity.