Revisiting 39: penis fish on California beaches

A 12/12 story in the Guardian, “Thousands of ‘penis fish’ appear on California beach: Fat innkeeper worms typically burrow under the sand but recent storms have swept away layers, leaving them exposed” by Vivian Ho, beginning:

(#1) A beachgoer holds a fat inkeeper worm – otherwise known as a ‘penis fish’ – in Bodega Bay in June 2019 (photograph: Kate Montana / iNaturalist Creative Commons)

I’m not sure this is what the Weather Girls meant when they sang, “It’s raining men.”

Following a bout of winter storms in northern California, “thousands” of pink, throbbing, phallic creatures wound up pulsating along a beach about 50 miles north of San Francisco, Bay Nature reported.

(Hat tip to Ned Deily.)

The Guardian story continues:

According to the nature magazine, these 10in wrigglers are marine worms [Urechis caupo] called fat innkeeper worms, but they are known colloquially as exactly what you’d want to call them: penis fish.

These penile figures typically burrow under the sand, far beneath the feet of beachgoers, but the recent storms brought on some waves that swept away the layers, leaving them exposed.

(#2) Masses of penis fish at Drakes Beach in Point Reyes National Seashore (photo courtesy of David Ford on Instagram)

… seagulls enjoy gobbling up these penis fish, as do otters, other fish, sharks and rays. But the penis fish is a human delicacy to some as well. In South Korea, they call it gaebul.

Ah, we have been here before, in my 8/5/12 posting “Snakes, worms, fish, clams, slugs”, on penis snakes, penis worms, penis fish, and other phallic creatures, including one of several called penis fish: Urechis unicinctus:

a species of marine spoon worm. It is widely referred to as a Fat Innkeeper Worm or the penis fish [also known as the sea penis]. The spoon worm is commonly eaten raw with salt and sesame oil in Korea and in part of Japan. (Wikipedia link)

This is the Korean gaebul, a different species in the Urechis genus from the California penis worms. I haven’t found any information on the edibility of Urechis caupo, but Wikipedia has an otherwise splendid encyclopedia article on that species (immensely informative, though compressed through reliance on technical vocabulary that not everyone might appreciate):

Urechis caupo is a species of spoon worm in the [annelid] family Urechidae, commonly known as the innkeeper echiuran, the fat innkeeper worm, the innkeeper worm, or the penis fish. It is found in shallow water on the west coast of North America where it forms a U-shaped burrow in the sediment.

Description: Urechis caupo is a plump, unsegmented, cylindrical pink worm growing to a length of 50 cm (20 in), with 20 cm (8 in) being a more typical length. There are a pair of setae (bristles) on the ventral surface at the anterior end, and a distinctive ring of about ten setae around the anus at the posterior end. The proboscis is short.

Distribution and habitat: Shallow water in the northeastern Pacific Ocean is the habitat of U. caupo; its range extends from southern Oregon to northern Baja California. It lives in a burrow in muddy sand in the lower intertidal and the shallow subtidal zone.

Ecology: This spoonworm is a detritivore [NOAD: an animal which feeds on dead organic material, especially plant detritus] and creates a U-shaped burrow in the soft sediment of the seabed. When feeding, it presses a ring of glands at the front of the proboscis against the burrow wall and secretes mucus which sticks to the burrow wall. The worm continues to exude mucus as it moves backwards in the burrow, thus creating a mucus net. The worm draws water through its burrow by peristaltic contractions of its body and as food particles pass through the net they adhere to it. When enough food is gathered, the worm moves forward in its burrow and swallows the net and entangled food. This process is repeated, and in an area with plenty of detritus, may be completed in only a few minutes. Faecal pellets accumulate around the worm’s anus, and periodically the worm contracts its body sharply to produce a stream of water from the anus that blasts the pellets and loose sediment from the tube, creating a casting on the surface of the sand. [AZ: This spoonworm analogue of ejaculation is in fact explosive defecation. On literal spoonworm ejacuation, see below.]

Larger food particles are rejected and discarded in the burrow where they provide food for the many different commensal organisms which share the burrow, resulting in this spoonworm being known as the “innkeeper worm”. These include the California softshell clam (Cryptomya californica), pea crabs, shrimps and scaleworms. The arrow goby (Clevelandia ios) uses the entrance of the burrow as a refuge into which it can dash if danger threatens. The gut of the spoonworm often contains many trophozoites of the protozoan Zygosoma globosum.

The sexes are separate and fertilisation is external. The eggs are pinkish or yellowish and the sperm are white, being liberated into the water through a pair of modified nephridia. The larvae are planktonic for about sixty days before settling on the seabed; they are strongly attracted to settle in the vicinity of other spoonworms by a chemical released from the castings.

On nephridia, from NOAD:

noun nephridium (plural nephridia): Zoology (in many invertebrate animals) a tubule open to the exterior which acts as an organ of excretion or osmoregulation. It typically has ciliated or flagellated cells and absorptive walls. ORIGIN late 19th century: modern Latin, from Greek nephrion (diminutive of nephros‘kidney’) + the diminutive ending -idium.

The Wikipedia description of U. caupo ecology doesn’t encourage me to consider shopping for the worms, to eat them raw with salt and sesame oil as is reported for U. unicinctus in Korea and Japan. (On the other hand, I have eaten, with pleasure, raw, indeed still quivering, molluscs of several species, whole or sliced as sushi, so maybe I shouldn’t be so reluctant about penis fish.)


Leave a Reply

%d bloggers like this: