Holothuria edulis — a type of slow-moving sea cucumber about the size of a classroom ruler — boasts an important ocean role despite its uncanny resemblance to an overcooked sausage.
(From ScienceDaily) — This “Burnt Hot Dog” sea cucumber takes center stage in a new genetic study that digs into the animal’s valued spot in marine ecosystems across Japan’s Okinawa Island as well as its extreme vulnerability to environmental stress and overfishing. A team of researchers, including an expert from the California Academy of Sciences, says their study’s findings are an urgent call for increased fisheries management and protections for ecologically important sea cucumbers, sometimes called the “vacuum cleaners of the ocean,” worldwide. The study was recently published in the journal Conservation Genetics.
Sea cucumbers, the often-overlooked cousins of starfish and sea urchins, are soft-bodied marine invertebrates that appear in myriad sizes, shapes, and thrilling colors in every ocean on Earth. More than 1,500 species — including pleasingly-named “Sea Apples,” “Strawberries,” and “Sea Pigs” — inhabit global oceans from the shallows to the mysterious deep seafloor. Despite their wide-reaching range and diversity of species, one Academy researcher says scientists need to know more about sea cucumbers’ biology, natural histories, and ability to adapt to the modern threats of pollution, overfishing for food and medicine, and changing ocean climate.
“It’s easy to underestimate the sea cucumber,” says Dr. Iria Fernandez-Silva, an Academy postdoctoral research fellow. “Sea cucumbers look goofy, move slowly, and barf up their guts when startled, but these invertebrates are superstar ocean cleaners that are hugely important to marine ecosystems. Our study looks into the genetics behind the economically-important species Holothuria edulis so we can understand the pressures they face and help protect threatened sea cucumbers globally.”
Like other sea cucumbers, nocturnal H. edulis use their guts to help clean seafloors and coral reefs. These Burnt Hot Dog invertebrates take shelter during daylight hours before emerging at night to inch along the sandy seafloor in search of food. Feeding tentacles help the animal shove sand and rubble through its digestive system as it moves, absorbing nutrients from detritus (dead plant and animal matter) and expelling cleaner, oxygenated sand in its wake. Healthy marine ecosystems rely on animals that provide these types of frequent cleaning services; without them, an abundance of detritus can impact plant and animal health, which in turn decreases the health of the ecosystem as a whole.
A rapid rise in East Asia’s consumer demand for sea cucumbers for both food and medicine has increased fishing pressures in many parts of the world. Overfishing can spell extinction for species of sea cucumber that already face serious pollution and habitat destruction threats worldwide. For example, populations of Holothuria whitmaei and H. scabra — once common in the entire Indian and Pacific oceans — have recently declined 60 to 90 percent in most of their traditional ranges. Today, at least 16 species of sea cucumber are considered threatened with extinction by the International Union for Conservation of Nature (IUCN) Red List, a global authority on the conservation status of plants and animals.
Read the full article here: https://www.sciencedaily.com/releases/2016/03/160322100404.htm