Sand Collar Season....or More Tiny Stuff to Figure Out

The Moon Snail, Puget Sound's largest intertidal snail is currently in the middle of its breeding season (April-Sept).  Most sand and gravel beaches have egg cases (sand collars) in abundance.  The snails are separate sexes, with females growing faster and being larger than males.  Mating is rarely observed as it takes place under the sand or subtidally. Moon Snails begin to breed when about 2.2 inches in size.  Females can store sperm for up to 6 weeks before fertilizing the eggs which are mixed with a mixture of sand and glue and extruded in the form of a collar.  If you are really lucky you may witness this process by observing a collar sort of magically emerging from the sand.  The whole process takes about 20 to 40 minutes.  In all instances of witnessed egg laying I have seen the female has been upside down in the sand while laying the eggs (only dug up after eggs were laid).  The sand collar contains some 3 hundred plus thousand eggs.
Life expectancy is about 14 years maximum.
Adults feed on clams and other snails which they either drill with the rasping radula or suffocate.  Drilling is assisted with an organ that produces enzymes and hydrochloric acid to weaken the shell of the victim.
Drilled holes are countersunk which distinguishes them from holes drilled by other snails or octopuses.
Drilling rate is about 0.5mm per day and the process of eating the prey take about a day.  Moon Snails favor soft or thin shelled clams and avoid the thick shell Heart Cockles.  In turn Moon Snails is fed upon by Sunflower Stars, Red Rock Crabs, gulls, octopuses, and when small, Northern Clingfish and likely other fish.
While some people do eat Moon Snails, certain First Nations peoples of Canada did not as they were said to make the eater stupid.  Since Moon Snails feed on clams which may contain toxins that can affect brain function this seems like quite good advice...Don't eat them.

If one closely examines the concave surface of a sand collar on the beach it becomes evident that lots of things are using it to lay eggs, perhaps as cover, or feeding on the Moon Snail eggs.  Some of the items found are tiny and difficult to identify which makes it all the more interesting....if sometimes frustrating for anyone who wants to know it all.  Images below show some of the action on the collar surface.

SAND COLLAR STUFF (many of these are 1cm or less in size)


Lacuna snail on sand collar



Dove Snails on sand collar



Barnacle Eating Sea Slug on sand collar



Flat Worms



Opalescent Sea Slug



Barnacles on sand collar



Top Snail on egg mass on sand collar



Unidentified worm on sand collar



Top Snail on sand collar



Moon Snail with sand collar



Moon Snail with clam victim



Moon Snail making sand collar

Moon Snail siphon on surface collecting air



Moon Snail damaged shell from gull attack



Moon Snail drilled clam




Opalescent Sea Slug eggs



Hansine's Sea Slugs eating Opalescent Sea Slug eggs (?)

Phyllodoce williamsi  Worm eggs



Olea hanisneensis  sea slug eating Opalescent Sea
Slug eggs



Olea hanisneensis sea slug on sand collar

Lacuna snail and eggs

Opalescent Sea Slug Ho Down

Flatworm with flatworm eggs on sand collar

Unidentified snail on sand collar

Teamwork, Olea Sea Slug style

Lacuna with decaying seaweed wit
h unknown white pattern