WaterNotes

Hold It!

Marine mammals and reptiles (and even some birds like shearwaters) have to hold their breath if they want to dive down for food in the ocean environment.  Its rather amazing how long some of them can go without fresh air.  Bottlenose dolphins can go about ten minutes, walruses can manage twenty, harbor seals can eek out thirty minutes on a good day.  Of course the marine reptiles blow them right out of the water since sea turtles can hold their breath upwards of five hours.

Yes, five hours.  In fact there is a species (maybe a subspecies) of turtle in the Pacific - the black sea turtle - that is known to hibernate for five months at the bottom of the ocean.  So you could argue that they can hold their breath for 3600 hours!

Still, all of the marine mammals beat the average human.  On average, people manage to hold their breath forty seconds to one minute.  (Even polar bears beat that by holding their breath for two!)  The truly interesting thing, to me, is the behavior that people exhibit while holding their breath.  Its interesting, because as far as I know, these behaviors don’t necessarily help you hold your breath longer. 

Many people pinch their nose and swallow so much air that their cheeks balloon up.  Others will forego the cheeks but keep the pinched nose.  Practically no one continues to go about their normal buisness and very very few people fidget. 

Why does that seem significant to me?  Well.. marine mammals don’t just hold their breath and space out!  They have lives to run and fish to catch beneath the waves.  Their breath holding periods are active, and they still manage to keep things under control for incredibly long periods compared to us. 

[PS: The trick to holding your breath longer than a minute - my best time is 1′45″ - is to slightly hyperventilate by taking three huge breaths quickly and then holding the fourth breath and starting the clock.  It seems to push out the old air.  Free divers do it.  Most marine mammals naturally do this, they exchange out huge volumes of air with each breath and are in essence always breathing deeply.  Humans exchange a paltry 17% of lung volume on an average breath while bottlenose dolphins exchange 80%!]

Come to think of it I have a question about oxygen consumption in people!  I’m a runner and we sometimes talk about VO2 max when training.  Basically its how much oxygen your body can consume and efficiently process, its also a measure of how fit an athlete is.  But what I’m curious to know: can athletes hold their breath longer than the average population or does their increased muscle mass impose higher oxygen demands on the system and lower their breath holding ability?  Hmmm.  Any exercise physiologists out there care to set me straight? 

Shark Perception, Not the Ampullae Either

I’ve pondered in the past whether or not our culture’s perceptions of animals get in the way of our ability to understand and protect certain species.  Sharks are a perfect case in point.  Sunday starts the annual celebration of all things tiburon on Discovery’s famed Shark Week. 

In the past the documentaries have diligently attempted to allay fears about sharks by replacing it with knowledge about their biology, habitat use, and the reasons behind their interactions with people.  Sometimes these presentations toe the line between reinforcing and relieving our preconceived ideas about sharks as mindless eating machines interested in consuming everything in their path.  This year seems to be starting off right so far - while the lineup of shows has some dubious titles - they do have a shark expert blogging away about shark conservation. 

Oceana brilliantly timed the release of their report about shark conservation, Predators as Prey: Why Healthy Oceans Need Sharks, earlier this week.  If I were teaching a class on marine conservation, this report would be required reading.  Of all the details presented I was most intrigued by the top-down control shown by tiger sharks upon dugong and green sea turtle species in Australia.  Oysters may be a manatee’s best friend here in Florida but tiger sharks are a seagrass bed’s ally down under. 

Hulu.com posted a sharkumentary, “Search for the Great Sharks”, (released way back in 1992) that presents a classic foul-up with sharks in the media.  Its focus is more on entertainment and hyping the few moments of surprise and stress in the film than on real conservation messages or actual information.  And it continues to light sharks in a negative glow by emphasizing the unfortunate - if uncommon - attacks on people instead of illuminating the damage we have done to their populations. 

The worst part of the film?  At twenty-five minutes a researcher is actually shown gasping and screaming as a white shark surfaces to attack a tuna strung out on a chum line.  Give me a break!  Scientists can be scared - sure - but should we really encourage audiences to continue to believe that fear is a reasonable reaction to a relatively natural feeding behavior?  It would be acceptable if she was shown laughing at herself later on for such a silly moment of hysteria, but it never comes. 

I desperately hope that this year’s Shark Week will overcome the typical sharkumentary and will find a way to inspire awe and respect over fear and paranoia and to further the conservation message.  Let’s not forget the strange math tied up in our interactions with sharks.  For every human killed by a shark - we kill - accidentally or purposefully - ten million of them.  On average ten people die due to shark attacks while one hundred million sharks are taken directly or caught as bycatch each year. 

And the truly horrifying thing?  This number doesn’t include decreases in populations of sharks whose food sources have been effected by overfishing, degradation of habitat, or outright habitat loss.  It also doesn’t reflect the changes in population structure and size that we are also seeing in several species, even in the world’s largest fish, the whale shark.  Remember, its all connected. 

There is one connection that I would like to sever… this long lasting idea in our culture that sharks are something to fear and dread and that they do not deserve the same sort of protection that more charismatic animals like dolphins and sea turtles so easily inspire. 

Stop! Turtle Time!

Summertime on any Floridian beach makes my heart pound.  No, its not the scenery of half naked guys (ha!), its the invisible world beneath the sand grains that makes me nervous. 

Green and loggerhead sea turtles regularly nest on the Atlantic beaches in Florida and the coastline at the Merritt Island National Wildlife Refuge is routinely dotted with mounded sand piles from late April well into September when the hatchlings emerge (in an event called an ‘emergence’ no less). 

Locals are well aware of the significance of these weird yellow stakes and half-submerged chicken wire squares.  But tourists often have no clue that the sand contains the next generation for these endangered species.  (And each nest averages fifty to two-hundred eggs!)

Which leads me to anxiously eye the nests around my beach campsite and watch the coming and going of all the visitors like a hawk.  In the past I’ve patiently gone up to people who were perilously close to the nests and explained their importance.  Its true though that I’ve just as often approached those who were literally stomping on top of the wire with a rather flustered emotional state.  I’ll admit, I’ve yelled more than once; “Stop!  It’s turtle time!”

While I realize it isn’t exactly my job to be an ambassador or a patrol officer to guard sea turtle nests along the coast I feel compelled to protect them whenever I hit the beach.  If I can keep just one pair of crushing feet off a nest then I’m willing to put myself in the way and share my (perhaps passionate) love of sea turtles with the unsuspecting tourists who stray too close for comfort. 

If you also share an obsessive love for sea turtles and you live in Florida there are a number of organizations who could use your time, talents, interests, or just a donation.  Check these out:  Honu.org / Sea Turtle Preservation Society / Florida Sea Turtle License Plates (I’ve got one!)

Ospreys In Love (In Downtown)

Ah, ze osprey. These gorgeous little birds of prey attract their mates by using French accents. No really, they do. I swear!

Okay so ospreys don’t use French accents; in fact the dynamics of mate selection and pair bonding in these raptors is not well understood. Are the females impressed by nest construction? Prowess in catching fish? Size of the talons?

Which makes for a cool aside in fact. Ospreys have very powerful feet, like all true raptors. But in addition to talons that are several inches long they have spines on the bases of their feet that work like the cleats that athletes use. These spicules don’t give the birds traction on playing fields though. They help them to hang on to their meals of somewhat slimey fish.

How do they catch such fish? By literally dropping out of the sky and hurtling towards the water at breakneck speeds to slam into the unsuspecting fish. The feeling of free-fall you experience on a roller coaster is what ospreys go through every time they hunt down a meal. They’re the stunt junkies of the Floridian skies.

Its so much more impressive than the dives of brown pelicans. (Speaking of which, brown pelicans are the only diving pelicans. Isn’t that strange? I thought they all dove for their meals!)

I snapped this photo a while back along the Indian River Lagoon system, an estuary where fish abound and ospreys are easily spotted. But lately I’ve been shocked and surprised to find ospreys far into the interior of the state, even in downtown Orlando!

The birds will perch along the corridors of major highways like the 408 and the 417 and hunt at the edges of the large lakes in the area such as Lake Eola.  In fact I was driving home two days ago and saw an osprey with a huge fish in its clutches and saw the bird make some enormously athletic navigational corrections as the fish squirmed and twisted during the flight. 

Its always a shock to me to see wildlife out in areas of high urban development and surrounded by noise and human activity. It really makes you wonder just how adaptable some species truly are and how our culture will impact - or provide opportunities - for such animals in the future. 

Still, I worry about the downtown ospreys.  Florida’s landscapers love their fertilizer and other chemicals and it doesn’t take much to offset the delicate balance of the natural lakes in our area.  I wonder, if the lakes get unhealthy, if the raptors will migrate out to the coasts.  (Or, even better, if the downtown ospreys actually roost and nest downtown… or if they return to the coastline every night after hunting in the central lakes.)

Homegrown Pineapples?

Living in Florida certainly has its advantages when it comes to climate.  Except when its the end of July.  Right now its so hot that M&M’s actually do melt in your hand before they ever make it to your mouth.  By ten in the morning the weather is absolutely steaming; nearly eighty-five Fahrenheit and easily seventy percent humidity.

But one of the nice things about a relatively stable year round temperature - if not stable year-round rainfall - is the effect it has on growing seasons in the South.  I can actually squeeze two to three rounds of tomatoes out of the garden, same for peas.  Lettuce is finicky in the hottest months but from October to about March there’s plenty of it. 

And considering our rather Hawaii-like climate, we can actually get pineapple to grow in the front yard.  Same for avocado and mangoes. (Although mangoes really do best in the southerly points like Miami.  In fact mangoes grow so well in the 305 area that my Dad used to talk about having mango wars and chucking them like grenades when he was a kid.)

One of the most interesting things about growing pineapples is the crazy way you can generate a plant.  Four years ago I called my friend Annie crazy (crazy!) for attempting this method but it turns out that it actually works.  If you lop off the top of a mature pineapple and leave a bit of flesh at the bottom you can then put the top in a bit of water for a few days, plant it in the ground, and actually get a new plant out of it! 

I still feel like its a bit of science fiction but the plants growing in my parents yard prove it for fact.  (Well, unless my parents bought real pineapple plants and put them in the same spot just to prove their point.  Which I doubt.)

Now comes the hard part: the wait.  Most of the veggie and fruit books say pineapple takes roughly two years before its mature enough to harvest fruit.  Some say longer.  Hopefully the anticipation will make the eventual fruit taste even better; rather like biting into oranges fresh off the trees in “winter” and having to wait a full year before they’re in season once again. 

I thought there were a lot of interesting things to say about anticipation and food, but it seems one of my favorite authors has already written them.  Barbara Kingsolver’s Animal Vegetable Miracle is excellent reading, and I’m only ten pages in. 

Name Games: Sea Lions and Sperm Whales

Combining my love of words and language with my love of ocean life often has strange consequences.  For instance, I happen to be fascinated with the stories and origins behind common animal names.  In fact, I’m so often asked for the reasons for animal names that I’m beginning to prefer that we only use Latin names, which if impossible to pronounce are at least easier to explain!

Take the species name for Northern fur seals for example: Callorhinus ursinus.  If you remember your trips to the planetarium as a kid the “ursinus” epithet should stand out.  Think Ursa major and Ursa minor.. the big and little bear constellation in our skies.  Yep, ursinus is a reference to being “bear-like”.  In fact, at one point Northern fur seals were known as sea bears! 

(Which must have proved difficult to distinguish them when polar bears were discovered.  Especially since their species name is Ursus maritimus.  Literally, “sea bear”!)

In the case of the Northern fur seals’ close cousin the California sea lion you might wonder how “lion” fits as their description.  They’re loud animals, sure, but their barks and growls don’t exactly sound like roars.  And while one male does preside over a large harem of females in rookery situations during the pupping and breeding season, they don’t exactly form up stable lifelong social units like prides.  So what gives?

Apparently the appearance of male sea lions, which have huge foreheads (called a sagittal crest) and very thick necks that protect them during territory sparring matches, led mariners to believe their necks looked like the manes of land lions. 

I can’t say that I precisely see the reasoning behind any of it but that’s the story behind the moniker.

There’s a somewhat amusing one for sperm whales as well.  Sperm whales were extensively hunted as an oil resource by American whalers sailing out of Nantucket and other whaling capitals in the 1800’s.  In these whales - like many other species - the forehead region (or melon) is full of lipids that allow for sound projection during echolocation.  The melons of sperm whales are enormous and the oils found in this region were the easiest source to extract.  Oil made from the blubber had to be heated and boiled down before stored in casks on board the vessels. 

Whaling crews were exclusively men; lonely men far from home without iPhones or Blackberrys to keep them entertained.  (Hmm.)  They called the oil from the heads of sperm whales “spermaceti” for its apparent resemblance to seminal fluid.  Gross, but true.  From that observation and description its an easy jump to their modern name “sperm whale”. 

Try sharing that at your next dinner party. 

Lovely Lepidoptera

The butterfly garden at the Florida Museum of Natural History is a gorgeous site.  I wouldn’t mind having something similar in my backyard; an aviary of fine mesh and butterflies dancing about. 

Of course, I’d have to keep only Florida natives.  And it would be a tremendous amount of upkeep to maintain a stable population.  The adults just don’t last very long.

Then again, if I could raise painted lady butterflies in the dead of winter in Delaware for entomology class I suppose keeping zebra wing butterflies in Florida might not pose such a hurdle.  I wonder if they can also exist on grape jelly.  Or perhaps I should be feeding them something much more organic? 

Apex Meets Apex, Hmm

Killer whales are truly phenomenal creatures.  And I am scared to death of them.  Honest.  I would rather swim in a pool full of bull sharks, lemon sharks, and white sharks than get into water anywhere near an approaching pod of transient (or even resident) orca. 

Why this aversion?  All you have to do is view the video.  Ever since I saw a Blue Planet episode I’ve had a paranoia about these gorgeous predators.  In that footage the film makers tracked a pod of killer whales that stalked a grey whale mother and her calf until the calf became exhausted.  They took turns breaching on top of the calf and submerging him until he drowned. 

Now I can appreciate a well coordinated attack just as much as anyone.  And I sure do understand the dynamics of predator and prey quite well.  Its not that I have a bleeding heart for infant animals being eaten - its just the easiest prey to capture - but it was the behavior the orca presented after the kill that astonished me and started the unsettled feeling in my stomach. 

What did they do?  After they had tracked these whales for hundreds of miles and expended considerable energy in the hunt they ate only the tongue and parts of the bottom jaw from the calf.  The rest was left to float like so much flotsam in the ocean. 

Its not that I find it disrespectful or wasteful (or some other insensible anthropomorphic projection) it was simply an overwhelming example orca’s efficiency and skill.  The kill was almost easy, and they certainly weren’t desperate … they left most of the carcass behind! 

Now it seems that not even white sharks are safe from orca.  If CA2 can teach this breach trick to her calves or podmates “Jaws” may be in trouble with “Shamu”.