<p><strong>SF Fig. 2.6.</strong>&nbsp;(<strong>D</strong>) Herbivorous collector urchins (<em>Tripneustes gratilla</em>) are placed on reefs to control invasive algae.</p>

SF Fig. 2.6. (D) Herbivorous collector urchins (Tripneustes gratilla) are placed on reefs to control invasive algae.

Image by Narrissa Spies