DLNR press release (17 August 2010) - The use of native collector urchins to manage invasive seaweed on a patch reef in Kaneohe Bay

Department of Land and Natural Resources Division of Aquatic Resources diver placing native collector sea urchins on a patch reef to study the effect of sea urchin grazing on algae abundance.

Department of Land and Natural Resources Division of Aquatic Resources diver measuring coral and invasive algae cover on a patch reef in Kaneohe Bay.

Invasive species is checked for native species before being bagged. Native species are rarely found inhabiting the seaweed, but those that are found are returned to the reef.

Native collector sea urchins grazing on invasive algae in Kaneohe Bay. This study showed that by augmenting the native urchin population, the Kappaphycus is effectively managed and the reef was kept clear of the smothering growth.

Native collector sea urchins grazing on invasive algae in Kaneohe Bay. This study showed that by augmenting the native urchin population, the Kappaphycus is effectively managed and the reef was kept clear of the smothering growth.

Native collector sea urchins grazing on invasive algae in Kaneohe Bay. This study showed that by augmenting the native urchin population, the Kappaphycus is effectively managed and the reef was kept clear of the smothering growth.

Rice coral in Kaneohe Bay partly covered in the invasive algae Kappaphycus. Invasive algae grows faster than coral. Its thick growth can block sunlight, smother and kill coral, which also reduces habitat for other reef dwellers.

Coral reef in Kaneohe Bay partly covered in the invasive algae Kappaphycus. Invasive algae grows faster than coral. Its thick growth can block sunlight, smother, and kill coral, which also reduces habitat for other reef dwellers.

Coral reef in Kaneohe Bay partly covered in the invasive algae Kappaphycus. Invasive algae grows faster than coral. Its thick growth can block sunlight, smother, and kill coral, which also reduces habitat for other reef dwellers.

Sea urchin actively eating algae. Algae fragment is in the sea urchins mouth.

Corals on a patch reef in Kaneohe Bay are kept clear of invasive algae by native sea urchins that have been placed there to graze the algae.

Corals on a patch reef in Kaneohe Bay are kept clear of invasive algae by native sea urchins that have been placed there to graze the algae.

Native collector urchins placed on the patch reef were kept to half of the reef where they grazed invasive algae. On the half of the reef without sea urchins, invasive algae proliferated.

Corals on a patch reef in Kaneohe Bay are kept clear of invasive algae by native sea urchins that have been placed there to graze the algae.

Rice coral and finger coral reef in Kaneohe Bay partly covered in the invasive algae Kappaphycus. Invasive algae grows faster than coral. Its thick growth can block sunlight, smother, and kill coral, which also reduces habitat for other reef dwellers.

Coral reef in Kaneohe Bay partly covered in the invasive algae Kappaphycus. Invasive algae grows faster than coral. Its thick growth can block sunlight, smother, and kill coral, which also reduces habitat for other reef dwellers.

Two Supersucker barges removing invasive algae from a patch reef in Kaneohe Bay. Divers guide the Supersucker hose to vacuum the seaweed, which is deposited on a sorting table prior to bagging.

A graph showing the effect of sea urchins on algae abundance over a one year time period.