What do blue whales, penguins and salmon have in common?
They all have the same diet. Much of the ocean is fed by a two-inch crustacean: krill. Antarctic krill congregate in huge masses in the Southern Ocean, dense enough to fill the belly of a blue whale, the world’s largest animal.
Penguins will march hundreds of miles to feast on krill, building up blubber that will help them survive their cold months on land. Even flying seabirds will dive in and partake of the abundance.
Without this tiny creature, the ocean would starve. But like so much else in the ocean, krill’s future is in danger. It is also a popular food for salmon, giving the fish’s meat that distinctive pink color. When humans build fish farms for predatory fish like salmon, we need to feed them. And that means that humans are now fishing krill to feed our farms, taking away potential meals from whales, penguins, and other wild creatures.
Oceana is working to prevent the overfishing of krill and the other small creatures that keep the oceans’ food chain going. To learn more about marine animals like Antarctic krill, visit our marine wildlife encyclopedia.
When you think of ocean animals, snakes are not usually the first thing to come to mind, but they live as comfortably underwater as they do on the ground. Today’s Marine Monday features one of these swimming snakes, the olive sea snake.
Olive sea snakes live in corals in the waters above Australia. Divers should be cautious around these olive-brown snakes, as they will swim right up to anything that catches their curiosity, and they will bite if they feel threatened. An olive sea snake bite is venomous and can be fatal.
But don't worry, beachgoers have little to fear from this snake. Olive sea snakes live and hunt within their own small territories in coral reefs and rarely enter open water.
One cool thing about olive sea snakes is that they have a nine-month gestation period and give birth to live young, just like us! But their babies come in litters of five and are the size of a human finger, plus they grow up to be venomous sea snakes, so the similarities end there.
Want to learn more about cool marine creatures? Check out Oceana’s marine encyclopedia.
The whale shark is the largest fish in the world and can fit a human inside its mouth. But don’t be afraid: this huge fish eats only plankton and small fish, which it gathers by pumping water over its gills.
The whale shark is one of three sharks that filter feeds, and the only one that does so actively rather than relying on simply swimming forward with its mouth open. Despite this, the whale shark has about 300 very small teeth, the purpose of which is unknown.
In addition to being the largest species of fish on the planet, whale sharks also have the thickest skin of any animal – about four inches thick. This skin is decorated with a pattern of yellowish white dots that is unique to each shark.
Whale sharks are usually solitary, but they can feed in groups. One particularly striking example of this behavior occurs around April off Australia, when immature males gather to feast on particularly plentiful plankton. Throughout their travels, whale sharks often cross entire oceans.
Whale sharks are considered vulnerable. One of the most important threats they face is shark finning – although their fins are not very popular to eat, because they are so large, they are highly prized for displays. In 1999, just one whale shark fin sold for around £11,000. Other threats include hunting for liver oil and meat and being caught accidentally as bycatch. It’s not all bad news, though! Some areas are protecting whale sharks in order to foster ecotourism.
Oceana’s shark campaign focuses on reducing shark bycatch, establishing shark finning bans, and implementing species-specific shark management.
The crown-of-thorns starfish is named for the brightly-colored spikes that coat its legs. This starfish can grow up to 16 inches across and has between 12 and 19 legs instead of the usual five -- that’s a lot of spikes!
These spikes hold poison that can cause temporary paralysis at the sting site and nausea in humans. Like other starfish, the crown-of-thorns can regrow arms. At the end of each of these arms is an eyespot that can detect light and darkness, although not color or shape.
Crown-of-thorns starfish are avid eaters of coral, and just one starfish can eat 13 square miles of coral each year. In order to eat the coral, the crown-of-thorns starfish pulls its stomach out of its body to cover the coral, then feeds through tiny hairs called cilia. All that remains of the coral is its white skeleton. Despite being voracious eaters, crown-of-thorn starfish can survive food shortages of up to six months by living off reserves.
Since the 1970s, plagues of crown-of-thorn starfish have been occurring more and more frequently, particularly in Australia's Great Barrier Reef. Scientists are still debating whether these are natural or have been caused by overfishing crown-of-thorn predators.
There aren’t many creatures interested in such a prickly snack, but a few mollusks and fish like the giant triton and the titan triggerfish play important roles keeping crown-of-thorn starfish populations under control.
Learn more about the crown-of-thorns starfish and other fascinating animals at Oceana’s marine encyclopedia.
Starting today, we’ll be doing a weekly trivia feature of one of the fascinating species that lives in the oceans. Today’s animal is the Kemp’s ridley sea turtle.
Kemp’s ridleys are the smallest and most endangered species of sea turtle. These turtles are usually solitary and live primarily in the Gulf of Mexico and Caribbean, sometimes venturing up the Eastern Seaboard.
The relatively small range of the Kemp’s ridley sea turtle is one of the reasons its population has been declining. When population concentrations are high enough, females come onshore to lay their eggs arrive together in mass landings (the name of these landings is our weekly trivia question on Twitter, so answer now to win!) Eggs and hatchlings make easy prey for dogs, herons, and humans—and some cultures believe sea turtle eggs are aphrodisiacs.
Adult sea turtles are particularly at risk of drowning after being accidentally caught in the nets of shrimp trawlers and other fishermen. Adding turtle excluder devices to nets allow turtles to escape and have made a difference in turtle bycatch deaths, although these rates are still high. Oceana’s sea turtle campaign focuses on preventing sea turtle bycatch, protecting habitat, and promoting legislation that keeps turtles safe.
Got the winter blues? In need of intellectual stimulation, or a vacation to a tropical destination -- or both? Or are you just a proud ocean geek? Either way, it's your lucky day.
Yesterday we launched our brand new Ocean IQ Quiz, where you can use your ocean smarts to win prizes -- including a trip to Baja California.
After you take the quiz, you'll have a chance to enter the sweepstakes to win a slew of prizes. The grand prize winner will travel with ecotourism organization SEE Turtles on an exclusive eco-adventure to observe sea turtles in the wild.
And the other prizes are not too shabby either: Nintendo Wiis with a copy of the ocean exploration game Endless Ocean, plus dive watches, gift cards and rope bracelets from Nautica.
Plus, this pop quiz is open-note. You can beef up your score by utilizing our Explore section, and you can take multiple quizzes if you're one of those over-achiever types.
So go on, test your ocean IQ! I know you want to. And all the cool kids are doing it.