giant purple sea urchin

For example, the sea urchins Strongylocentrotus purpuratus and S. franciscanus can be induced to release their eggs and sperm simultaneously, but most of the fertilizations that result are between eggs and sperm of the same species. In animals with internal fertilization, sperm cells may be unable to function in the…

on the herbivorous urchins (genus Strongylocentrotus) enables kelp forests and the fish associated with them to flourish. However, large numbers of sea otters can deplete shellfish populations, competing with fisheries for crabs, clams, and abalones. Female sea otters give birth in water to only one young at a time, and…