Australia’s Giant Cuttlefish in Trouble as Weak Spawning Season Continues

Australian giant cuttlefish may be in trouble, as evidenced by low summer spawning numbers (flickr| richard ling)

This summer, numbers are way down.

Australia’s ABC Radio recently interviewed a local commercial fisherman who reported that he has only seen four this year—rather than the usual “hundreds of thousands.” Other news outlets have been picking it up too.

Researchers say the low numbers are cause for concern, and they don’t yet know what’s causing the trend (though “BHP Billiton’s proposed desalination plant” nearby probably won’t help. It would reportedly pour “huge quantities of hypersaline wastewater” into Spencer Gulf and make the area unpalatable for a variety of species). A new study finds that the cuttlefish breeding colony had decreased by 78% in the past decade, and last year marked a record low.

Plan to Exonerate Hawaiian Monk Seals Relies on Reality-TV-style Cameras

Hawaiian Monk Seal photo by: U. S. Fish and WIldlife Service

The image rehabilitation plan comes as local fishermen ramp up  claims that the seals have been depleting area fish stocks. Recent cases of people pestering—and in some cases killing—the seals have come partly as a reaction to these rumors, and spurred scientists to “glue submersible cameras onto the seals’ backs, using the footage to prove to fishermen the animals are not harming their way of life.”

You can find out more about habitat threats to monk seals or read Les Welsh’s blog post from April about people intentionally killing the seals in the waters around Kaua’i (and how you can help).

Video: Blue Shark Chomps Giant Squid

Giant squid are mysterious, awesome and locked in an eternal arms race with sperm whales. Live sightings are so rare that even footage of a recently dead Architeuthis is a pretty big deal. Recently, Australian angler and journalist Al McGlashan came across a largely-intact carcass whose bright red coloration indicated it had died recently. While he filmed, a blue shark tore into the squid, thus launching  the best cephalopod viral phenomenon of 2012 (so far…I eagerly await your videos of octopuses singing ‘Call Me, Maybe’). Take a look at Field & Stream’s exclusive full-length video and photos right this second.

Click here to view the embedded video.

Canadian Lobster is Blue, Yet in Decent Spirits

Canadian lobster boat captain Bobby Stoddard caught a lobster in early May that resembled a giant Avatar cat person. That’s the way we say ‘it was blue’ in America now.

Blue lobsters do occur, but they’re uncommon. According to The University of Maine’s Lobster Institute, “only an estimated one in two million lobsters is blue” (which makes them rare, but not quite as rare as live, naturally red or yellow lobsters, which are estimated at one in ten million and one in 30 million, respectively). Blue lobsters come about due to “a genetic defect that causes the lobster to produce an excessive amount of a particular protein.”

You can learn more about invertebrates in our Wildlife Library.

Manta Ray Ultrasound Sheds Light on Liquid Oxygen Intake

A study recently published in Biology Letters is the first to show how manta ray embryos get oxygen, based on video from an ultrasound performed on a pregnant ray in 2008.

Though manta rays, like many other cartilaginous fish, give birth to live young, they lack an oxygen-giving umbilical cord or placenta. According to researchers, “the baby ray was raising and lowering its jaw, pumping uterine fluid in through its mouth and spiracle.” The continuous regulated flow of the fluid over the ray’s gills allowed the embryo to extract oxygen (the baby was “a healthy female, 2 meters from wingtip to wingtip and weighing 50 kilograms” at birth). According to Taketeru Tomita, a fish biologist at Hokkaido University Museum, this is the first time that scientists have observed fetal viviparious vertebrates pumping liquid to extract oxygen.

Great Whites Summering in Cape Cod

Researchers tag a shark near Chatham, MA, in 2009. Tagged great whites recently returned to Cape Cod to feed on seals. (flickr | Massachusetts Energy and Environmental Affairs)

Researchers say the sharks were drawn to the area by “a growing seal population on Monomoy Island,” redoubt of migrating birds and other non-humans for hundreds of years. They haven’t come close enough to tourist beaches to warrant any official warning, though mayhem will presumably occur if the star-crossed Brody family gets too close.

For more on ocean creatures, see Kevin Coyle’s post from last year about animals’ various methods of swimming or my post about the Top 5 Real Sea Serpents (including the giant squid). You can also check out an article about sperm whales and the threat posed to them after the oil spill in the Gulf  of Mexico.

If you’ve seen a story that you think should be covered in the next Ocean Wildlife Roundup, please let me know in the comments below, email me at greenbergm@nwf.org, or tell me on Twitter @MaxTGreenberg.

Perfume and Love Songs

Wild animals have a bit of a different spin on these traditional ways of attracting and wooing a lover.

• Female moths release a chemical called a pheromone into the air that male moths find irresistible.  The males detect the females’ intoxicating perfume with their fuzzy, sensitive antennae.  A single female moth can lure dozens of males. The bolas spider has figured out a way to mimic the pheromones of certain moths, thus luring unsuspecting male moths to an untimely death in her clutches.  Talk about deadly perfume!
• Male wood frogs emerge from hibernation in February and brave the near-freezing water of ponds formed by melting snow, where they put out their loud duck-like mating call to attract females. Being amphibians, wood frogs are cold-blooded and their body temperature is essentially the same as the surrounding freezing pond water. An antifreeze-like property in their body is the only thing that keeps these croakers from freezing solid. No love in front of a toasty fireplace for these guys!
• Some insects have learned how to take advantage of the irresistible visual display of the opposite sex as a way to score a meal.  Male fireflies flash their light and wait for the females hidden in the vegetation to flash back. One species of firefly has learned to mimic the return flash of the female of another species, and when the hopeful male shows up to introduce himself, she eats him and goes on to mate with a male of her own species with a full belly.

Ladies’ Choice

For many species the females hold all the power and ultimately decide when to seal the deal when it comes to mating. And the males have to work hard to earn their prospective lady’s attention!

• The male bowerbird is every woman’s dream: he’s an excellent carpenter but also fabulous decorator. He builds a stick structure called a bower and then decorates it to impress the eligible ladies.  Often he picks a monochromatic color scheme for his decor, which can include everything from shells, feathers, flowers, and even bits of string, plastic and other man-made items.  If the house and its decor are good enough, females will choose him as their mate. It’s clear no human male teenager whose room looks like a war zone would ever score with this approach.
• Male painted turtles have very long front claws.  When he’s trying to impress a particular gal, he swims around so he’s facing her and then waves his perfect manicure in her face in the hopes of turning her on.  She’s likely to be simply annoyed by his flashy behavior, though, and he runs the risk of having her swim away if she’s not in the mood.
• Location, location, location – In spring, male house wrens migrate north a week or two before the females.  They use that time to build multiple nests to impress the girls when they arrive.  A male has got to have impressive building skills to score a mate.  When a female finally does pick a male and one of his abodes, she moves in and promptly disassembles his “bachelor pad” nest and rebuilds it to her own satisfaction. Sound familiar?

Gender Benders

Boys will be boys and girls will be girls.  But for animals, it’s doesn’t always work that way.

• In many human societies, it’s the women who traditionally wear makeup, jewelry and pretty clothes to catch a guy’s eye, but in the bird world it’s the guys who sport the fancy ornamentation.  Females usually have drab, earthy colors to better camouflage them while they sit on the nest.  A male’s flashy feathers are an indication that he’s in good health and can father fit offspring with a good chance of survival.
• Some fish start out one sex and switch to another.  They live in groups where all are one sex or the other with the exception of the largest individual, who is the opposite sex of all the smaller fish.  If the largest individual is eaten by a predator, leaving the group all male or all female, the next largest fish changes sex so the others will have a mate. Great incentive to stay fit and muscular so you’re ready to take over if the need arises.
• Some animals can be both sexes at once so they are never lonely on Valentines Day.  Some species of sea slugs can be male, female, or hermaphroditic. With so many sexual options these slimy mollusks often engage in orgies of 20 or more slugs of various persuasions.
• The Australian cuttlefish doesn’t change sex, but when a male is feeling the urge to get his groove on with the ladies but is thwarted by a bigger, tougher male, he’s got a trick up his tentacles.  He can change his color and shape to mimic a female and slip right by the big guy who would otherwise chase smaller males away.   The best part is that the females are more than happy to mate with these diminutive but clever guys right behind the backs of their more buff brethren.

Singles Only

If these sexual strategies were options for humans, the Valentine’s Day industry would go out of business!

• Sex is only one way that animals reproduce.  Some don’t need to mate at all in order to create offspring.  Many one-celled organisms simply divide into two.  Others, such as the hydra, can reproduce sexually but if all the potential mates look like losers, they can grow buds that break off and grow into new individuals.
• Some animals have a kind of “virgin birth” called parthenogenesis.  The female just clones herself, producing eggs via cell division rather than from the joining of sperm and egg.  Without sex there’s no exchange of genetic information, and the resulting offspring are genetically identical to the mother. So much for DNA testing. A female aphid can produce thousands of little clones this way.  For some bee species, the queen can produce different kinds of offspring depending on whether her eggs are fertilized. The fertilized eggs all hatch as females, while her unfertilized ones hatch out as males.

National Wildlife Federation naturalist David Mizejewski is available for press interviews on this and other wildlife subjects.