Collector urchin
Encyclopedia
The collector urchin is a species of sea urchin
. Collector urchins are found at depths of 2 to 30 m (6.6 to 98.4 ft) in the waters of the Indo-Pacific
, Hawaii
, and the Red Sea
. They can reach 10 to 15 cm (3.9 to 5.9 ) in size.
s are also white, with a dark or black base. Individuals found at Green Island had orange-tipped spines. The spines of some specimens are wholly orange, while those of others are only orange-tipped or completely white. This colour disappears when the individual dies or is taken out of the ocean
, and is difficult to preserve. Collector urchins reach 10 to 15 cm (3.9 to 5.9 ) in size. Debris tends to "collect" on these urchins, hence their name.
Unlike some other sea urchins, collector urchins graze continually, day and night. They graze near the substrate, and their diet includes algae
, periphyton
, and seagrass
. Most collector urchins feed on seagrass fronds; this has an ecological impact varying with the season and abundance of the urchins. They feed voraciously between November and January; one study found they consumed up to or in excess of half of seagrass production. On an annual basis, however, the same study concluded that about 24% of seagrass production is consumed by the collector urchin. The seagrass species grazed are mainly Thalassodendron ciliatum and Syringodim isoetifolium, but other algae may also be consumed.
Collector urchins are prey for puffer fish, octopus
and humans.
, Hawaii
, and the Red Sea
. They are distributed from Mozambique
to the Red Sea, westward to Hawaii and Clarion Island
, eastward to Paumotu, and as far south as Port Jackson
. It also occurs at Shark's Bay on the west coast of Australia
. Mature collector urchins prefer open sea bottoms with some cover, but the young prefer rocky areas for concealment. Collector urchins inhabit depths of 2 to 30 m (6.6 to 98.4 ft).
genus
Kappaphycus, also known as "smothering seaweed," which has overrun local coral
. Tripneustes gratilla stays on the reef and is an effective algae grazer.
The urchins were bred at Anuenue Fisheries Research Center from about a million larvae
. The larvae produced 25,000 specimens that reached at least 15 millimetre (0.590551181102362 in) in diameter in about five months. The delicate young had to be kept suspended in the water column for weeks after hatching. The project intends to release 10,000 to 25,000 urchins per month.
Kaneohe Bay is the only barrier reef
system in the United States. The alien seaweed was brought to Hawaii for commercial applications such as keeping ice chunks out of ice cream
. It escaped when the industry failed.
For years, the state used a marine vacuum pump to remove the algae, at one time removing 10000 pounds (4,535.9 kg). In 2009, the scientists gathered urchins from other parts of the state and released them at Kaneohe Bay. A year later, they found the urchins had successfully kept the seaweed down.
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
. Collector urchins are found at depths of 2 to 30 m (6.6 to 98.4 ft) in the waters of the Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, and the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
. They can reach 10 to 15 cm (3.9 to 5.9 ) in size.
Description
Collector urchins are dark in colour, usually bluish-purple with white spines. The pediclePedicle (zoology)
In zoology, the pedicle refers to a fleshy line brachiopods and some bivalve mollusks use to attach and anchor to a substrate. In brachiopods, the pedicle emerges from a pedicle opening. Some brachiopods do not have a functional pedicle, and thus do not have this pedicle opening....
s are also white, with a dark or black base. Individuals found at Green Island had orange-tipped spines. The spines of some specimens are wholly orange, while those of others are only orange-tipped or completely white. This colour disappears when the individual dies or is taken out of the ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
, and is difficult to preserve. Collector urchins reach 10 to 15 cm (3.9 to 5.9 ) in size. Debris tends to "collect" on these urchins, hence their name.
Unlike some other sea urchins, collector urchins graze continually, day and night. They graze near the substrate, and their diet includes algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, periphyton
Periphyton
Periphyton are a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that are attached to submerged surfaces in most aquatic ecosystems. It serves as an important food source for invertebrates, tadpoles, and some fish. It can also absorb contaminants; removing them from...
, and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
. Most collector urchins feed on seagrass fronds; this has an ecological impact varying with the season and abundance of the urchins. They feed voraciously between November and January; one study found they consumed up to or in excess of half of seagrass production. On an annual basis, however, the same study concluded that about 24% of seagrass production is consumed by the collector urchin. The seagrass species grazed are mainly Thalassodendron ciliatum and Syringodim isoetifolium, but other algae may also be consumed.
Collector urchins are prey for puffer fish, octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
and humans.
Distribution and habitat
Collector urchins are found in the waters of the Indo-PacificIndo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, and the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
. They are distributed from Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
to the Red Sea, westward to Hawaii and Clarion Island
Clarion Island
Isla Clarión, formerly called Santa Rosa, is the second largest, westernmost and most remote of the Revillagigedo Islands, west of Socorro Island and over from the Mexican mainland and an area ². It has three prominent peaks. The westernmost and tallest peak, Monte Gallegos, is high...
, eastward to Paumotu, and as far south as Port Jackson
Port Jackson
Port Jackson, containing Sydney Harbour, is the natural harbour of Sydney, Australia. It is known for its beauty, and in particular, as the location of the Sydney Opera House and Sydney Harbour Bridge...
. It also occurs at Shark's Bay on the west coast of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Mature collector urchins prefer open sea bottoms with some cover, but the young prefer rocky areas for concealment. Collector urchins inhabit depths of 2 to 30 m (6.6 to 98.4 ft).
Relationship to humans
Collector urchins are economically important in some parts of the world. They are edible and sometimes exploited by humans; as a result, they have become less abundant. Over the past ten years, overexploitation has caused a sharp decline in the collector urchin population.Harvesting algae
Hawaii state aquatic biologists, working with divers from the Hawaii Division of Aquatic Resources placed 1,000 native collector urchins on a 500 square metres (598 sq yd) area of reef in Kaneohe Bay on January 29, 2011. The urchins were released to help control the invasive seaweedSeaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Kappaphycus, also known as "smothering seaweed," which has overrun local coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
. Tripneustes gratilla stays on the reef and is an effective algae grazer.
The urchins were bred at Anuenue Fisheries Research Center from about a million larvae
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...
. The larvae produced 25,000 specimens that reached at least 15 millimetre (0.590551181102362 in) in diameter in about five months. The delicate young had to be kept suspended in the water column for weeks after hatching. The project intends to release 10,000 to 25,000 urchins per month.
Kaneohe Bay is the only barrier reef
Barrier reef
Barrier reef may refer to:*a kind of coral reef*the Great Barrier Reef in Australia*the Mesoamerican Barrier Reef System*the Belize Barrier Reef*the New Caledonia Barrier Reef*Barrier Reef , an Australian television series...
system in the United States. The alien seaweed was brought to Hawaii for commercial applications such as keeping ice chunks out of ice cream
Ice cream
Ice cream is a frozen dessert usually made from dairy products, such as milk and cream, and often combined with fruits or other ingredients and flavours. Most varieties contain sugar, although some are made with other sweeteners...
. It escaped when the industry failed.
For years, the state used a marine vacuum pump to remove the algae, at one time removing 10000 pounds (4,535.9 kg). In 2009, the scientists gathered urchins from other parts of the state and released them at Kaneohe Bay. A year later, they found the urchins had successfully kept the seaweed down.