Honolulu Star-Advertiser © Susan Scott
June 28, 2010
Last week, during an early morning beach walk, I found a zillion little pink things lying in wavy lines just above the shore break. At first I thought the crusty casings were the molted shells of some kind of shrimp. But these were the whole animals, still fresh from their grounding. Big black eyes bulged from each side of the creatures’ tiny heads and pairs of soft, pliable legs curled beneath the bodies.
There were two species, the largest about the size of a dime, and the other, far more numerous, half that. Because both were so small I couldn’t make out much detail. I brought a handful home and took some pictures.
After sending the photos to two specialists, searching the Internet, paging through three invertebrate zoology textbooks and two field guides, I still don’t know what they are. I do, however, have clues, both from their appearance and from the conditions in which they arrived.
In their broadest category, these animals are crustaceans. This name comes from the Latin word “crust,” meaning brittle, and refers to animals having a flexible external shell as opposed to a hard shell like a snail or clam. Most crustaceans, which have gills, antennae and stalked eyes, live in or near the ocean. Crustaceans are so abundant in the world’s oceans they are sometimes called the insects of the sea.
With more than 50,000 crustacean species in the world (and counting), the variety is nearly endless, and the sorting of them a maze. After blowing up my pictures, and counting legs, I could place the pink things in only the broadest of categories: Decapoda, meaning 10 legs.
In decapods, the front two legs often have pincers or paddles at their tips. The last four pairs are walking legs, sometimes modified for swimming. We humans know this group well. Shrimps, lobsters and crabs are decapods.
Because about 12,000 decapods swim, walk or drift in the oceans of the world, identifying them gets tricky. And if the adults aren’t enough to sort through, decapods also go through growth stages that don’t usually resemble their mature bodies. Baby crabs, for instance, hatch from eggs as free-swimming larvae and then go through a series of molts, some appearing quite different from each other, and from the adult.
The smallest Kailua pink things could be crabs in an early stage of development called a zoea (zo-EE-a). The larger creature looks like a baby slipper lobster.
A Colorado visitor I met on the beach on pink-thing morning wondered if these deaths might be a symptom of a red tide. She also mentioned the oil spill.
It’s certainly reasonable to be concerned about the state of the oceans. I believe, though, that this grounding was normal because among the pink things were Portuguese man-of-wars, an offshore creature frequently blown onto our shores during windy conditions. I also found a tiny flying fish not much bigger than the pink things.
Steady tradewinds such as we’ve been having create currents that can overpower swimming or drifting offshore animals. And in Hawaii, offshore isn’t far away. It’s common on windy days to see open-ocean creatures in our bays and on our beaches.
If anyone can identify the crustaceans that decorated Kailua Beach last week, please let me know. I’d love to call them something besides pink things.