DIVE DRY WITH DR. BILL #904: THOSE AREN'T PUMPKIN SEEDS!

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drbill

The Lorax for the Kelp Forest
Scuba Legend
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DIVE DRY WITH DR. BILL #904: THOSE AREN'T PUMPKIN SEEDS!

Come spring I often find a lot of what look like pumpkin seeds on hard surfaces at the bottom of the dive park. Halloween is long gone so they aren't the work of underwater pumpkin carvers. Oh, how I used to love scraping out those pumpkin seeds and chowing down on them! Add a little pumpkin pie and whipped cream and I was in heaven. Well, not quite as I was topside instead of underwater!

But these "pumpkin seeds" aren't what they seem. They are the egg capsules of a local snail known as a Kellet whelk (Kelletia kelletii). These gastropods have a very thick shell that is usually white or tan but can be different colors due to algae growing on it. The foot is orange to yellow in color. They may reach nearly 7" in length, making it one of the largest species in our waters.

This snail is found from Monterey into Baja California in depths ranging down to about 230 ft. Habitat preference is for rocky bottoms and kelp forests but they may also be seen on sand or mud.

Kellet whelks are scavengers. I have seen them feeding on a variety of dead fish including a bat ray. They will also enter lobster traps to chow down on the bait inside. They have a very long, extensible proboscis that can extend into small cracks to feed. In addition they will feed on sea urchins, limpets and other species of snails.

They are a slow growing species and a 3.5" specimen may be 20 years old. Females are sexually mature at a little over 2.5" in length. Fertilization occurs internally and the embryos are laid inside the egg capsules. Spawning occurs from March to May. Upon hatching the larvae disperse in the plankton for an undetermined time. Populations need to be fairly dense as mating is done in aggregations as seen in the image.

Predators on these snails include octopus, sea stars, Moon snails and sea otters. Reproduction can be dangerous for the Kellet's whelk. Since they usually aggregate in fair numbers when mating, they create a tempting smorgasbord. Several times I have observed giant (aka knobby) sea stars (Pisaster giganteum) atop a mating cluster with its tube feet firmly attached to several of the snails.

Native Americans fed on this species as I have witnessed during our analysis of archaeological middens here on the island back in the late 1960s and 1970s. There is a modern day commercial harvest as well, limited to about 100,000 lbs. A reported 98% of the take comes as incidental by-catch in lobster and crab traps. I've never tried eating one. With my culinary "skills" it is probably safer that way.

© 2021 Dr. Bill Bushing. For the entire archived set of nearly 900 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page

Image caption: Two Kellet whelks and one laying a cluster of pumpkin seeds; a clear shot of the eggs and a cluster of mating individuals; rocks covered with eggs and some attached to a golf ball!


DDDB 904 Kellet whelk mating sm.jpg
 
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