Introduced Species Summary Project
Killer Algae (Caulerpa taxifolia)
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Common Name: Killer Algae (hybrid form)
Scientific Name: Caulerpa taxifolia<![if !vml]><![endif]> (Photo from Makowka, J. 2000)
Phylum or Division: Chlorophyta
Identification: A bright green algae with feathery branches that vary in length from 5-65 cm. in tropical waters, while the hybrid form grows much larger with plants up to 10 feet.
locations, with hybrid form having spread throughout much of the
Site and Date of Introduction: Probably
introduced into the
Introduction: The hybrid form of Caulerpa taxifolia was most likely produced as a result of the
tropical form having been captively bred for a number
of years by the Saltwater Aquarium at the Wilhelmina Zoo in
Reason(s) Why it has Become Established: It is an extremely hearty plant that can withstand severe nutrient deprivation, in fact it can survive out of water for up to 10 days. It can thrive in even heavily polluted waters and appears able to colonize most habitats and adapt to any milieu. It has been found in habitats that are nutrient-poor such as sandy bottoms, rocky outcroppings and mud. It can live at a variety of depths, and can cover up to 100% of the sea bottom from the surface to a depth of 35 meters. It has been observed at depths up to 100 meters. Although patches are less dense at such depths, it seems to grow to the underwater limits of vegetation. It can survive in a variety of temperatures, from tropical to temperate waters. It contains a toxin that is not harmful to humans but may be lethal to certain species of fish and invertebrates and may interfere with the eggs of some marine organisms. The plant appears unpalatable to general herbivores, and seems to grow unrestrained and develop into a dense, uniform carpet that blankets an area and persists from year to year. Other marine life leaves the area, and there are even indications that it may kill off many microscopic organisms. It has displaced rich habitats like eelgrass beds that sustain a complex food chain leaving the area unable to sustain a variety of life forms.
Role: Where Caulerpa taxifolia
exists, it tends to carpet the area and become the dominant form of plant life.
The creation of a dense algal expanse
across a sandy bottomed sea floor alters the nutrient dynamics of the
sediment. Vast quantities of organic
matter tend to increase oxygen consumption in the area. Caulerpa taxifolia is known to have crowded out the sea grasses
Benefit(s): Due to the extremely negative ecological and economic damage that has been done by the accidental introduction of this mutation into the wild, it is actually not possible to identify any benefits associated with this species.
This fast-growing algae
has been dubbed “killer algae” because it crowds out other plants
and animals as it colonizes an area with great monotypic stands of vegetation. It
displaces rich marine habitats that support a variety of fish and invertebrate
life, and leave an area unable to nourish animal life. It has
recently been reported to be smothering seagrass beds in Sydney Australia. The attempts by
In addition to the profound threat to biodiversity, it is likely to cause widespread economic harm through reduction of marine fisheries yields, entanglement with fishing nets and choked access to harbors and marinas.
Level Diagnosis: Highest Priority.
Experts believe it has established too strong a foothold in the
has been identified by the Global Invasive Species Specialist Group as being
among the 100 worst invasive alien species threatening biodiversity. The threat it poses to marine environments
was acknowledged by the government of the
It is generally recognized that if an
outbreak is to be controlled it is critical to identify the plant at the
earliest stages of arrival in a marine environment. Mechanical controls have been attempted in
portions of the
In terms of biological controls, two species of snail have been identified that attack the algae, Aplysia depilans, and Elysia subornata. However, due to the dangers the introduction of a new species can cause to an ecosystem, neither snail has been released for testing on the plant in open water.
Mackenzie, Debbie, The Starving Ocean, July 2001. http://www.fisherycrisis.com/seaweed.html
Makowka, J. 2000,
Madl, Pierre and Maricela
Yip, Literature Review of Caulerpa taxifolia – Updated
Simberloff, Daniel, Impacts of Introduced
Species in the
Thibaut, T. and A. Meinesz,
2002. Management Successes and Failures in the
Author: Karen Imparato Cotton
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