Ocean Watch
By Susan Scott
My mother-in-law is one of my most loyal readers. This may not sound remarkable, but Claire doesn't live here -- she lives near Seattle. There, each Friday, this 78-year-old marine biology buff boots up her pretty blue computer, reads this column online and e-mails me some insightful comment about the subject. Some fish migrate between
fresh water and the seaOccasionally, Claire tells me a story. These tales are always entertaining, but they sometimes seem to stray far from the subject of marine biology. After all these years, however, I know better. Her stories not only end with marine punch lines, they also end with challenging questions.
Here's an example. Claire recently escorted her granddaughter to a spelling bee. To show the children how it worked, the emcee asked for adult volunteers. Claire jumped to her feet.
She got the word DOG. "Is there an alternative pronunciation?" she asked. No. "What is its origin?" Middle English. "Is it related to the Washington Huskies?" No.
Claire gave it a stab: "D-O-Q"
It brought the house down.
Then the emcee gave her another word to spell: CATADROMOUS.
Claire had never heard the word and had no clue how to spell it. This time her questions were for real.
"Alternative pronunciation?" None. "Origin?" Greek through Latin. "Use it in a sentence, please?" Aquatic life that lives in fresh water and spawns in salt water is catadromous.
Well, this woman lives in salmon country and knew the word anadromous, which means animals living in salt water and spawning in fresh. With that clue, she spelled catadromous correctly.
That was the end of the story, but I saw Claire's question coming a mile away. "Does Hawaii have any catadromous or anadromous fish?"
It's a good question and the answer is a definite yes and no. We have in-between fish.
Hawaii hosts five native freshwater-saltwater gobies, called oopu. These fish hatch in streams, and then the tiny hatchlings get washed into the ocean. There the youngsters drift around as oceanic plankton and either get eaten or mature. After four to six months, depending on the species, the survivors head back upstream and start the cycle all over again.
When young oopu hear the freshwater call, their urge to swim upstream is strong. These little fish, only a few inches long, maneuver up the sides of waterfalls, using the suction-cup disk on their bellies to anchor themselves to wet rocks, and their pectoral fins to pull themselves up. Since oopu are true fish, they occasionally dip their heads into cascading water to catch their aquatic breath.
As if fish climbing up waterfalls isn't fantastic enough, Hawaii also hosts several native shrimp and snails that are also in-betweeners. The shrimp, called opae, hatch in streams, and after maturing in the ocean, move up directly through flowing water. Three kinds of snails also follow this pattern, some spending up to a year in the ocean. In the summertime, careful observers can see these dark, 1 1/2-inch snails following each other single file up streams.
Now here's a word for your spelling bee, Claire: amphidromous (am-FID-dre-mus). It's Greek to Latin, and here it is in two sentences. Animals that migrate between fresh and salt water after hatching and before spawning are called amphidromous. Since we humans have altered all of Hawaii's streams in some way, Hawaii's amphidromous animals are rare today.
Thanks, Claire, for sharing your great stories.
Marine science writer Susan Scott's Ocean Watch column
appears weekly in the Star-Bulletin. Contact her at http://www.susanscott.net.
