Counting eggs

So many eggs! Stacks of eggs in pink and yellow egg cases, glued to rocks. Hundreds, thousands, hundreds of thousands of potential baby snails ...

Egg cases of the Frilled Dogwhelk. From 20 to 80 eggs in each case.

  

One corner of one of the egg-laying rocks.

These are the egg cases of Nucella lamellosa, one of the most common intertidal snails on our shore. It  goes by many names: Frilled Dogwinkle, Wrinkled Dogwinkle, Rock-Dwelling Dogwinkle, (why "dog"?) Wrinkled Purple Whelk, Roman Purple Snail, Dog Whelk, Oyster Drill, and so on. The many names may reflect the extremely variable shell colours, shapes, and porportions. The ones I see on our shore aren't all that "frilled", but often wrinkled, and mostly whitish or grey, occasionally orange.

In this one section of the intertidal zone, in the margin between pure sand and a rocky, seaweedy area, many of the rocks were already coated with egg cases, with a line of snails at the base, still busy making more. 

This I didn't know; like salmon, upon reaching sexual maturity at 4 years of age, these dogwinkles return to the sites where they were hatched. There, the females gather with their sisters to attach huge masses of stalked egg cases on their home rocks.

A dogwinkle lives from 10 to 15 years; that gives each female 6 to 11 years of egg making. At about 1,000 fertile eggs a year, that would bury us under 10,000 new snails for each two adults. Good thing they don't all hatch! And that there is high mortality among the young snails; N. lamellosa is carnivorous, and the first hatchlings will eat the eggs of their siblings; then there are the usual predators, crabs and starfish, so only about 1% of the baby snails will make it to their first birthday.

One egg-laying rock. I count 60 adults busy laying eggs on this side of  the rock. Thousands of egg cases.

The new snails will hatch, depending on the temperature, in from 90 to 140 days. They hatch as tiny, perfectly formed snails, but are only about 1 mm. long.

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Huevos. ¡Tantísimos huevos! Montones de huevecillos en cápsulas color de rosa o amarillo, fijadas en las rocas. Cientos, miles, cientos de miles de caracolitos posibles ...

1. Cápsulas de huevos de Nucella lamellosa, el buccino púrpura arrugado. Hay desde 20 hasta 80 huevos en cada cápsula.
2. Una esquina de una de las rocas donde los caracoles ponían sus huevos.

Estas son las cápsulas que contienen los huevos de Nucella lamellosa, uno de los caracoles intermareales en nuestras playas más comunes. Es un caracol bastante variable en color y forma; los que veo más frecuentemente son blancas o grises, a veces anaranjadas; sus conchas son más bien lisas, no arrugadas como presupone su nombre común.

En esta area limitada de la zona intermareal, en un sitio limitado por arena limpia de un lado y rocas y piedras cubiertas de algas marinas del otro, muchas de las rocas ya estaban cargadas con cantidades de cápsulas de huevos, y tenían a su base un grupo de caracoles que seguían produciéndolas. 

Esto no lo sabía: al igual que los salmones, al la edad de 4 años, al llegar a la madurez sexual, estos caracoles regresan a los sitios de donde originaron. Allí, las hembras se juntan con sus hermanas para fijar grandes masas de sus cápsulas de huevos a sus rocas nativas.

Una Nucella lamellosa vive de  10 a 15 años, lo que le da de 6 a 11 añon en que puede producir huevos. Y produce alrededor de 1.000 huevos fértiles cada año. O sea, unos 10.000 nuevos caracolitos para cada dos adultos; suficiente para enterrarnos bajo una pila de caracoles. ¡Buena suerte es que no todos eclosionan! Y suerte, también que la mortalidad entre los caracoles juveniles es alta; N. lamellosa es carnívora, y los que eclosionan primero se comen los huevos más tardíos.  Y luego los atacan los predadores de otras especies, especialmente los cangrejos y las estrellas de mar. Al fin del primer año solamente el 1 porciento de los caracoles siguen con vida. 

• Una de las rocas cargadas de huevos de caracol. Visibles aquí hay 60 caracoles que siguen poniendo huevos.

Los caracolitos nuevos eclosionarán en unos 90 a 140 dias. Salen como caracoles perfectos pero miniaturos, midiendo apenas 1 milímetro.

Full moon and moon snails

The moon was full a couple of days ago. That means low tides again. I found a stretch of shore I had not visited before, and followed the water out.

This beach is mostly sand, overlaid with a young kelp forest. There were crabs everywhere, a grand mix of seaweeds, a few starfish, and from halfway down toward the water on, moon snail collars.

Moon snail "collar", or egg casing. Euspira lewisii.

I started counting moon snail collars as I walked along. Without going out of my way to look for them, I counted 67 in a half-hour's walk. The snails have been busy.

Moon snail collar, as found.

The moon snail is a large, round snail; its shell alone may measure almost 6 inches across, and the snail spreads out its body around and over the shell, almost doubling its size. This explains the shape and size of the egg collars.

"Collar" is probably the wrong word to describe these egg casings; it implies that they wrap around the egg mass. Instead, the collar is the egg mass.

The snail secretes a jelly-like substance, mixing it with sand, coating its body and shell (that's where the collar gets its shape.) Sandwiched between two layers of the sand/jelly mixture, she lays her eggs. Finished laying, she goes off to find food, leaving the egg sandwiches to lie on the sand for 6 weeks. Once the baby snails hatch, the collar disintegrates.

Other snails had been busy, too. Many stones were coated in whelk eggs.

Whelk eggs on stones, and another moon snail collar.

That's a lot of eggs! And a lot of future baby snails!

I started looking for adult snails. Now I left my direct route, zigzagging along the shore, looking for shells. Not one showed up. These snails burrow under the sand, looking for clams; sometimes on clean sand, their trails show up.

Or the tops of their shells. I did see one, but not until I looked at my photos. When I took this one, I was paying attention to whelk eggs, and completely overlooked the moon snail beside them.

Whelk eggs and moon snail, half hidden under the sand.

I did find one small (3 inches across) empty, broken moon snail shell.

I collected a handful of eelgrass to bring home for my aquarium critters. Washing the sand off at home, I discovered it was carrying many tiny, newly-hatched moon snails, none as big as the heads of my dressmaker pins. They're in the tank now. Most will not survive; most don't on the shore, either, or we'd be drowning in snails. I would like to see one grow up.

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Era luna llena hace un par de dias. Eso trae mareas bajas. Busqué un tramo de playa donde no había visitado antes, y seguí el agua mientras se alejaba.

Esta playa es arenosa pero cubierta con un bosque de algas "kelp" juveniles. Dondequiera había cangrejos, una gran mezcla de algas marinas, algunas estrellas de mar, y desde la mitad de la playa para abajo, los "cuellos" que contienen los huevos de los caracoles marinos "luna".

Primera foto: un cuello de caracol luna.

Empecé a contarlos mientras caminaba, sin andarlos buscando. En la primera media hora de caminata, conté 67 cuellos. Los caracoles se han mantenido ocupados.

Segunda foto: un cuello como lo encontré entre las algas.

El caracol luna es un caracol grande, redondo; su concha puede medir hasta 14 cm. y el animal extiende su cuerpo alrededor de la concha, llegando al doble del tamaño de la concha a solas. Esto es lo que les da la forma y tamaño a los cuellos.

"Cuello" puede ser una palabra mal aplicada, dando la idea de algo que cubre la masa de los huevos de caracol. Pero no: el cuello es la masa de huevos.

La caracol hembra produce una sustancia parecida a la gelatina, y la mezcla con arena, cubriendo su cuerpo y concha (de ahí que el cuello toma su forma). Entre dos capas de la mezcla, pone sus huevos, haciendo algo como un "sandwich" de huevo. Cuando termina de poner los huevos, se va a buscar comida, dejando el cuello allí en la arena, donde reposa por 6 semanas. Cuando por fin eclosionan los caracolitos, se desbarata el cuello.

Otros caracoles también pusieron huevos. Había muchas piedras cubiertas de paquetes de huevos de bocina.

Tercera foto: piedras con huevos de bocina, y otro cuello de caracol luna.

¡Son muchos huevos! ¡Y habrá muchos caracolitos!

Empecé a buscar los caracoles adultos. Dejé la ruta directa, haciendo zigzag, buscando conchas. No vi ninguno. Estos caracoles se meten debajo de la arena, en la caza de almejas. A veces, si la arena no está cubierta de algas, se ven sus huellas.

En todo caso, no encontré, allá en la playa, ningún caracol. Hasta que miré las fotos en casa; después de todo, había estado frente a uno, sin verlo porque me estaba fijando en los huevos de bocina.

Cuarta foto: más huevos de bocina, y un caracol luna medio escondido bajo la arena.

Quinta foto: la concha de un caracol luna rota y vacía.

Recojí un manojo de hierba marina Zostera para entretener a mis animalitos en el acuario. Al lavarla en casa, descubrí que llevaba un número de caracolitos luna recién eclosionados; el más grande no alcanza al tamaño de una cabeza de alfiler. Los puse en el acuario con la hierba. La mayoría no van a sobrevivir; tampoco lo harían en el mar: si no fuera así, estaríamos inundados por caracoles. Pero me gustaría ver que uno llega a crecer.

Thousands of eggs

 Sunny day. Low tide. Rocky shore, with tide pools.

I found whelk eggs!

Hundreds of egg cases. Thousands of eggs. And a few proud parents.

Down on my knees to get a better look.

Some are yellow, others are pink. I think these are frilled dogwinkles, Nucella lamellosa.

Work done, a whelk plows her way home.

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Un dia asoleado. Marea baja. Piedras expuestas a la luz del dia. Y pozas intramareales.

¡Y encontré huevos de bocinas (Nucella lamellosa)!

Fotos: 1 a 3: concentración de huevos en la zona baja. Cientos de sacos de huevos, miles de huevos.

Foto 4: una bocina, trabajo concluido, forma un surco en la arena.

#Invertefest

Using all three eyes

The camera sees more - and less - than my eyes do. Flipping rocks along the shore, left-handed, with the camera in the right hand, finger on the shutter button, I disturb crabs, who scuttle quickly under the next-door stone. Flip another; crabs. Another; more crabs. One stops to threaten me, pincers raised. "Come on, see if you dare!" I turn the camera in her direction, and she changes her mind and joins her friends under shelter.

Another stone. More racing crabs. Once they're gone, I see slow movement; flatworms. The camera sees them, unless the light is just exactly right, as brown smears. My eyes see the movement, the merest hint of it, going in a different direction than the slither next to it, the next flatworm.

Whelk egg cases, spiral tube-worms, and flatworms on the underside of a stone.

Wosnesenski's isopods, one lying upside-down for some reason, showing off his 14 legs. And a pair of crabs.

Sometimes, there's a nano-second of flurry, a miniscule splash; a baby sculpin, an inch long, gone to ground, now invisible. Maybe the camera will see him; I won't. But I saw the splash.

Some animals are only recognized, in these surroundings, by their movement. I learn to see them; the merest rise and fall of a limpet under the seaweed gluing herself down to the rock while the light threatens her; the split-second flip-flip-flip of a gunnel, the shrinking of an anemone, the characteristic sideways scuttle of a miniature hermit - snail shells don't move like that without a hermit resident; the writhing of a polychaete worm becoming one with the mud underneath, the squirting of a clam retreating deeper into the mud. The camera never sees those.

Spiral tubeworms, flatworms (the light was right- look for the eyes!) and a limpet, still on the move. I don't know what that tiny thing with the striped back"bone" on the stony patch in the centre is.

My eyes miss the very tiny critters. My reading glasses are in my pocket; they get in the way when I look through the viewfinder, and the light is too bright to see the screen. So I point and shoot, looking for the green square that says the auto-focus has found something interesting. Or find a safe, non-painful (broken barnacles are sharp!) place to kneel so that I can get my head down a few inches from the stones and look through the viewfinder.

White shells, a sea of white shells; must be barnacles. The camera knows better. Waving seaweeds; no, the camera discovers tentacles or antennae. Or a mass of worms.

The camera saw these. I didn't.

This photo includes two masses of ribbon worms; the upper one is a knot of Paranemertes peregrina (p. means wandering), the purple ribbon worm, with a very purple body and a creamy belly; the orange ribbon worm, Tubulanus polymorphus; and the green ribbon worm, Emplecotnema gracile, with its green top and yellow belly.

The lower knot appears to be all green ribbon worms.

And there are three flatworms and a trio of crabs.

Sometimes things are easier; I find an underwater species tossed up to die on the shore. These I can pick up and move to a better background.

Unidentified species of hydrocoral. Notice the yellow "bud" at the tip of the branches.

Habitat for the critters found above. The stripes parallel to the shore are probably old glacier tracks on sandstone.