Monday, May 11, 2020

Lifer under sand

The tide was as low as it gets in midafternoon. On a sunny Sunday. Everybody and their dog was on the beach, keeping their distance, but therefore covering most of the beaches. On the north end of Oyster Bay, I found an empty beach and walked along the water's edge to the sunken boats beside the breakwater, all baking in the sun this afternoon.

Looking back the way I came.  One of the larger ships.

The sand was covered with sand dollars, from the north end of the bay almost to the ships. Thousands of sand dollars; hundreds of thousands. Not much else. But around the old ships, the sand dollars gave way to a variety of other animals.

And I saw my first live moon snails!

The first thing I saw. A moon snail egg mass collar. The eggs have hatched.

And nearby, among many collars, a live snail, Lewis's moonsnail, Euspira lewisii.

These are large snails. The visible part of the shell was about the size of my fist, 3 inches across. The mature snail gets to about 5 1/2 inches across; that looks about right.

And though the snail may cram itself inside the shell, mostly it swells up and surrounds its shell, reaching 20 cm. or more in length.

Visible in the photo above is part of the foot, thought the two tentacles are not visible. The snail hadn't moved when I went on to the shore and the last ship, then returned. It may have been busy laying eggs.

A second snail. Here one of the two tentacles is exposed.

These snails burrow through the mud, looking for clams. They bore a hole in the clamshell to eat the clam inside.

Another egg mass collar underwater, intact, but without eggs. Also a beautiful green anemone.

The egg mass is a jelly containing thousands of eggs. They hatch into microscopic free-swimming veligers which later become snails. (Other snails hatch out as tiny snails, already in their shells.)

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La marea estaba a su nivel más bajo a media tarde. Y hacía sol. En domingo. Todo el mundo andaba en las playas, manteniendo su distancia, como se hace en estos dias, pero de ese modo cubriendo toda la playa. Cerca de Bahía de los Ostiones (Oyster Bay) encontré un espacio libre, y de allí caminé hasta llegar a los barcos hundidos afuera del rompeolas de la bahía. En el momento, no seguían hundidos, se estaban tostando al sol.

Toda la playa estaba cubierta de dólares de arena (galletas de mar). Miles de dólares. Cientos de miles. Y no mucho más; un gusano o dos. Pero alrededor de los restos de los barcos, ya había una variedad de animales.

Y por primera vez vi un caracol luna en vivo.

La primera foto es de un collar que protege la gelatina donde el caracol deposita sus huevos. Los huevos ya no están allí; habrán nacido ya.

En seguida, el primer caracol, casi toda enterrada en el lodo/arena. La parte visible de la concha es más o menos el tamaño de mi puño; unas tres pulgadas. El caracol maduro llega a 5 1/2 pulgadas; parece que este es un adulto. Y puede ser que esté poniendo sus huevos; no se mudó del lugar, aunque lo toqué, me fui, y más tarde regresé; seguía en el mismo sitio.

El cuerpo de estos caracoles es muy grande; con trabajos, sacando fuera el agua, logran encerrarse en la concha, pero normalmente se extienden alrededor de la concha, llegando a 20 centímetros o más de largo.

Los huevos, cuando nacen son "veligers", animalitos microscópicos con alitas para nadar. Luego se convierten en caracoles. (Algunas otras especies de caracol salen del huevo ya con su conchita.)


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