Monthly Archives: August 2015

Not all octopus mating ends with male’s death

Published August 31, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

blennies
A day octopus on Oahu’s North Shore. ©2015 Susan Scott

When courting, what does the male larger Pacific striped octopus sing to the female larger Pacific striped octopus?

“I want you back in my arms, arms, arms, arms, arms, arms, arms, arms again.”

For most octopus species, this would never be the song of choice because female octopuses sometimes eat their baby daddies. If males want to live to fertilize again, they must keep the object of their affection at arm’s length.

The larger Pacific striped octopus (LPSO for short), however, has a more friendly style of mating. In a recent study published in the online journal PLOS One, California researchers report that pairs of this species from the Pacific coast of Central America mate beak to beak, their 16 arms wriggling, grappling and hugging.

Typical octopus sex is as odd as the creatures themselves. Males have one specialized arm that stores and delivers sperm.

In most species, when a male and female meet, the male keeps his distance, stretching the loaded arm out to the female to deposit his sperm packet internally.

octo
Courtesy Arcadio Rodariche.

In one Tahiti study of the day octopus, Hawaii’s most common species, a male reached out and fertilized the same female 12 times in about three hours. He should have rolled over and gone to sleep: On the 13th transfer she ate him.

The word “larger” in the name “larger Pacific striped octopus” refers to a close cousin, the lesser Pacific striped octopus having a mantle about the size of a strawberry. The larger species’ mantle is about size of a tangerine.

An octopus mantle is the bag of flesh that in cartoon octopuses is depicted as a bulbous snout or bulging brain. It’s neither. The sack houses the octopus’s three hearts, liver, kidney and other internal organs. The animal’s impressive brain lies below the mantle between the eyes.

The 24 LPSOs in the California study had no interest in sexual cannibalism. One couple even shared a den and sometimes a meal, an oddity among octopuses, which usually lead solitary lives.

The LPSO researchers found another unique behavior in a hunting trick similar to the grade school prank of reaching behind someone and tapping them on the far shoulder to get them to turn the wrong way.

The LPSO does that, too, slowly reaching an arched arm, suckers up, over the top of a shrimp and giving it a tap it on the front of its upper shell. The startled shrimp scoots backward into the waiting predator.

Worth checking out are six short LPSO behavior videos near the end of the study. In the mating one, I imagine the grasping male singing, “I want to hold your hand, hand, hand, hand, hand, hand, hand, hand.”


Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2015 Susan Scott

 

Tiny blennies may be cute but they have a mean bite

Published August 24, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

blennies

Endemic Hawaiian zebra blennies. Credit Willy Asprey.

A friend of a friend of a friend placed a GoPro in a tide pool on Oahu’s North Shore. When he downloaded the footage, he saw eight adorable faces peering at the camera.

“OMG they are so funny,” emailed the middle friend, who wrote “sea monkeys” in the subject line. “Any idea what they are?”

Much as I love the name sea monkeys, the little charmers in the photo are called blennies.

Most blennies are timid reef fish that range from 4 to 7 inches long, depending on species. Some hide in holes, others live in tide pools and several rest in the open on rocks or corals. These bottom blennies eat algae and dead plant and animal tissue.

It’s easy to mistake blennies for gobies, and vice versa, because both have googly eyes, are similar in size and shyness, and hang out near rocky reefs. But here’s a clue: Startled blennies usually dash into holes tail-first; gobies dive in head first. Another sign is that many blennies have either frilly or antennaelike tendrils above their eyes. So if a fish with eyelashes or “My Favorite Martian” antennae is peeking from its hole, it’s a blenny. Gobies lack such tendrils.

Because bottom blennies have no swim bladders to control their buoyancy, the fish sink when they stop swimming. Some blennies make up for this bottom heaviness by performing acrobatics. When startled, they leap from pool to pool. One called the Hawaiian zebra blenny can detect a potential predator up to 50 feet from its tide pool. If the danger approaches, the fish will leap, skip or slide to the next pool, somehow knowing where that is.

Zebra blennies have been seen jumping as high as 2 feet above the water’s surface. Sometimes, the fish behave like frogs, slipping nearly out of the water to bask in the sun.

In addition to bottom blennies, the family has a branch of free swimmers called fang or sabertooth blennies. These fish use a set of curved lower teeth for defense. When caught by a predator, the blenny bites the inside of the captor’s mouth, causing it to spit out its potential meal intact. Unlike their vegetarian cousins, fang blennies are hit-and-run carnivores, nipping the sides of fish to eat mucus and scales.

The Ewa fang blenny mimics the cleaner wrasse, causing unsuspecting victims to swim toward the blenny thinking it’s going to lose some parasites. Instead, it loses some skin. Fang blennies sometimes bite divers, but the tiny nip does no damage.

I bought a GoPro recently and wasn’t quite sure what todowithit. I do now. I’m going hunting for sea monkeys.


Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2015 Susan Scott

 

Albatrosses receive help to prep for high sea level

Published August 17, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

cucumber

A Laysan albatross. The native birds need our guidance to nest on higher ground. ©2015 Susan Scott

Just when I’m feeling low about how humans treat wildlife on our planet, in comes the following news release from a local nonprofit group called Pacific Rim Conservation: As of July 1, 10 Laysan albatross chicks fledged from James Campbell National Wildlife Refuge on Oahu’s North Shore. The young birds’ launch signals the first success in a three-year project to create a new albatross colony.

The birds need new colonies because 99 percent of the world’s Laysan albatrosses nest in the low-lying atolls of Hawaii’s northwest chain. With sea levels on the rise, it won’t take much ice melt to flood the nurseries.

But persuading adult albatrosses to nest on higher ground is next to impossible. With the exception of a few pioneers, such as those that began a colony on their own at Kaena Point, albatrosses are hard-wired to nest where they were raised.

So rather than move adults, workers moved eggs.

For both albatross and human safety, each fall since 2004 workers at Kauai’s Pacific Missile Range Facility have collected albatrosses and their eggs from the runway area and taken them to Kilauea Point National Wildlife Refuge, home to a long-established albatross colony.

Adults released there consider their eggs lost and fly to sea to try again next year. But not all eggs are lost. Biologists tuck some under albatrosses whose eggs were either broken or infertile. Because there aren’t enough foster parents to brood all the PMRF’s runway eggs, leftovers are donated to researchers.

This year, though, in a translocation experiment sponsored by multiple agencies, biologists “candled” the extra eggs to find live embryos, flew those to Oahu and placed them in incubators.

Upon hatching, the tiny chicks were flown back to Kauai to foster parents whose eggs didn’t hatch. This crucial move caused the chicks to imprint on the correct species.

At a month old, the age when chicks get a fix on their birth location, the youngsters were flown back to Oahu’s James Campbell National Wildlife Refuge. There, amid a pretend albatross colony of decoys and recordings, workers for five months fed the chicks fish and squid slurry.

To everyone’s joy, all 10 chicks grew up and flew to sea, hopefully to return in three to five years to James Campbell. When they mate and start raising their own chicks there, a new colony will be born.

Learning the details of how countless people studied, carried, drove, candled, flew, incubated, flew again, fostered, flew another time, fed and sheltered those chicks renewed my faith in human compassion toward wildlife. Not everyone is out there shooting lions.


Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2015 Susan Scott

 

Much-loved migratory birds are winging back to the isles

Published August 10, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

cucumber

A kolea, or golden plover, makes a midwinter stop at Midway Atoll. The birds split time between Hawaii and Alaska, where they mate, lay eggs and raise their chicks. ©2015 Susan Scott

I am so excited that I had to tell someone,” emailed my neighbor Joanne. “My kolea is back!”

This message was one of several I received last week reporting sightings of Hawaii’s much-loved migratory shorebird, the Pacific golden plover, or kolea in Hawaiian.

As much as we love our lovely little plover pals, facts about the species can be hard to find. The following are questions from readers. My answers come from kolea researcher Wally Johnson’s published studies.

Question: How long do kolea live?

Answer: The average bird lives six to 10 years, but some live longer. One kolea wintered in a grassy field at Bellows Air Force Station for 21 years, three months.

Q: How long does it take for the birds to reach Alaska?

A: Kolea fly to their tundra breeding grounds, 3,000 or so miles from Hawaii, over open ocean in three days, about 72 hours. Their return flights to Hawaii take about four days due to adverse winds.

Q: Do kolea have chicks in Hawaii?

A: Never. Mating, egg laying and chick rearing all occur in Alaska.

Q: When do kolea migrate?

A: Underweight birds stay in Hawaii all summer. Healthy birds with enough fat stores to make the trip (the birds know) all leave around April 25, likely cued by day length.

Birds with failed nests due to predators or bad weather can return to Hawaii as early as June. Adults that successfully raised chicks come back in August, with females usually arriving before males. Juveniles appear in October and sometimes as late as November depending on fall weather.

Q: I have a kolea in my yard year after year. Is it the same bird?

A: Yes. Both male and female kolea return to, and defend, the same wintering site year after year.

Q: How do I tell a male from a female?

A: In winter you can’t. Both sexes molt into the same winter colors soon after they arrive in Hawaii. Keep watching, though. In spring the birds molt again. Males are brighter than females and have distinct edges to their black, white and gold feathers.

Over the decades, our kolea have learned to graze on grass and pavement, rest on rooftops and fence posts and steer clear of cars, cats and dogs. As a result of this remarkable adaptation to urban life, the birds give us city dwellers a heartfelt connection to nature.

That’s why a lot of us this month are so excited that we have to tell someone: My kolea is back!


Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2015 Susan Scott

 

Some sea cucumber species use poison to stop predators

Published August 3, 2015 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2015 Susan Scott

©2015 Susan Scott

©2015 Susan Scott

During my recent trip to Australia, I occasionally had Internet access to Hawaii news and learned that our sea cucumbers are in trouble because people have been harvesting them off Oahu and Maui. One headline in this newspaper said, “Sea cucumbers seem to need a friend right now.”

Well, little Hoovers of the sea, you’ve got a friend in me.

A more apt name for sea cucumbers would be sea sausages because they’re not veggies; they’re animals, hot dogs of the ocean that do a fine job of scrubbing the floor.

A ring of tentacles around sea cucumbers’ mouths sweeps the ocean bottom, picking up sand. The sea cucumber’s digestive system extracts bits of dead plants and animals from the grains and expels clean sand from its anus.

The sea cucumber has a busier anus than most animals — it also breathes through it. Inside the anus is a respiratory tree. Muscles around the branches circulate water to extract oxygen and release carbon dioxide. That’s why if you pick up a leathery sea cucumber, a stream of water often whooshes out of its anus.

The anus of some sea cucumber species provides shelter for several species of pearlfish, a narrow translucent fish that forages at night near its chosen host. Come dawn, the conspicuous pearlfish wiggles into its landlord’s anus and there rests, protected from daytime predators.

Not all sea cucumbers welcome pearlfish in their rectal chambers because the fish can get too cozy in there and start nibbling its host’s internal organs. Some sea cucumber species have a circle of five inward-pointing teeth around the anus, effective in keeping out potential parasitic squatters.

Hawaii hosts 50 or so species of sea cucumbers, half in shallow water, half in the deep sea. The diversity is large, ranging from firm and muscular to soft and squishy, and they grow from 1 inch to 3 feet long.

The squishy kind. ©2015 Susan Scott

The squishy kind. ©2015 Susan Scott

Because some fish eat the slow-moving sea cucumbers, they have evolved defenses you might expect to see only in sci-fi films. Some species shoot out sticky, toxic threads from their anuses to immobilize their enemies. Others produce a poison called holothurin that can kill fish and even people who eat them.

Another defense, called auto-evisceration, is what it sounds like. The creature ejects its internal organs, again through that all-purpose anus. This distracts the predator while the cucumber crawls into hiding. It takes a month or more for the organs to grow back.

A small species of sea cucumber. ©2015 Susan Scott

A small species of sea cucumber. ©2015 Susan Scott

A pearlfish barging into a sea cucumber’s anus doesn’t trigger the shooting of threads or the throwing up of organs. These defenses take place only when a threat occurs on the outside surface of the creature.

Some people like to eat several leathery species of sea cucumbers that live in Hawaii’s waters, but they aren’t abundant enough for limitless collecting. After the state discovered in June the commercial killing and selling of 3,000 to 4,000 individuals, the agency passed an emergency 120-day ban on taking any sea cucumbers in Hawaii’s waters. The agency is now working on long-term rules for the fishery that will keep the populations healthy.

Fortunately, our sea cucumbers have more friends that just me.

 

Sea Cucumbers

Sea Cucumbers at a remote French Polynesian Atoll. ©2015 Susan Scott

Marine biologist Susan Scott writes the newspaper column, “Ocean Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2015 Susan Scott