34 Biocontrol in Hawaiian Reefs

What is Biocontrol?

Biocontrol or Biological Control is the introduction of a natural predator into an environment in order to control a pest species. It is an important way to aid in the management of terrestrial and aquatic habitats that have been invaded by non-native species. Using natural methods is a great way to help troubled ecosystems without many of the negative impacts associated with chemicals and other non-natural interventions.

Here is a video by the Hawaiian Conservation Alliance of the work completed in the bay of Oahu, HI for the urchin biocontrol project.

Native Sea Urchin Biocontrol Example

Native sea urchins have been used as a form of biocontrol for algae overgrowth in Hawaiian coral reefs.

Two sea urchins in Hawaii by Opencage under [CC BY-SA 2.5]

A non-native species of algae was introduced to Hawaiian coral reefs in the 1970’s that quickly became invasive and invaded Oahu’s coral reefs. The algae grew so uncontrollably that it smothered out local flora and fauna and is still causing major issues for the Hawaii’s reef areas today. Herbivorous fish are highly impacted by this overgrowth. People spent up to 8 hours a day pulling algae from the reefs in attempts to control its growth to little avail.

Finally researchers discovered the idea that native sea urchins could be used to control the algae. Urchins are great at controlling algal growth because they graze on the algae. After the introduction of 100,000 urchins to the reefs, an 85% decrease of algae cover was observed after just 2 years!

Biocontrol Successes and Failures

Though there have been biocontrol failures highlighted in the media, such as the Cane Toad introduction to Australia, there have also been many great successes.

 

The information in this chapter is thanks to content contributions from Sarah Larsen  .

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A Student's Guide to Tropical Marine Biology by by Keene State College Students, BIO 381 Tropical Marine Biology is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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