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Dive Dry with Dr. Bill

#446: Orgy... At a Snail's Pace

A few years ago I wrote about market squid mating in our waters and used the word "orgy." A mother was reading the story to her five year youngster and complained to the editor of the newspaper about the use of the word. Not sure what else she expected from the Master of "Munching" and "Mating," but I thought I'd better warn my readers that I'm about to use the word again... so hide your kids. Let them watch the violent cartoons on Saturday morning TV, or play Mortal Combat on their computer instead. Wouldn't want them to think things like mating were a natural biological activity (although five years is a bit too early... at least for humans)!

Back in early June when ScubaBoard members were out for the DWADD (Ditch Work and Dive Day) prior to the SCUBA Show, we encountered dozens and dozens of Kellet's whelks (Kelletia kelletii) mating and laying their eggs in the dive park. These whelks (no relation to Lawrence) are snails with thick shells. I filmed them until the sediment stirred up by all the divers "muddied" the video. Then almost a week later I returned to the scene of the "crime..." and they were still at "it." Now that's what I call mating at a snail's pace. I'm sure there are some of my readers who wish their SO's had such staying power.

Although frequently free from any encrustation, the thick shells of these whelks are often deeply sculpted and may have anything from coralline algae to young giant kelp growing on them, . The soft foot of the snail is yellow with black lines and white spots. Kellet's whelks are known from Monterey down to Isla Asuncion off Baja, and may be found on a wide range of habitats including rocky reefs and sandy bottoms. They are most common south of Pt. Conception, suggesting that like the good doctor they are warm water wussies (nothing below 47 F for me thank you). . Their appearance north of there in central California is believed to have occurred within the last century and may reflect increasing water temperatures up there. Studies of intertidal marine life in Monterey, comparing the species present back in the days of my iconic marine biologist Ed "Doc" Ricketts with more recent data, indicate northern forms are being replaced by southern forms. I'm still waiting for warm water and coral reefs to replace the cool temperate waters and kelp forests here.

It has been reported that these snails mate in March and April, but the ones we saw were doing their "thing" in May and June. Temperature is often a trigger for mating activity, so it is quite possible they wait until the water is "just right." Unfortunately I'm often in "hot water" so that doesn't apply to me. During this period, their eggs may be seen completely covering rocks and other hard structures on the bottom. Actually what one sees are capsules containing several eggs. When a diver returns to the surface and mentions they saw "pumpkin seeds" attached to the bottom, I can reply with 99.99% certainty they they have observed these egg capsules.

An individual Kellet's whelk may lay as many as one thousand tiny eggs in up to 85 such capsules. Once the eggs hatch, the young larvae emerge and enter the plankton where they drift with the currents. They then settle out and begin their lives on the bottom. These snails are reported to live a long time. One with a three inch shell is believed to be 7-8 years old, and the maximum size is about seven inches. That makes them one of the larger shelled snails in California waters... but no match for the shell-less black sea hare (Aplysia vaccaria) which reaches three feet in length, making it the largest marine snail in the world.

Based on their experience with landlubber snails, many people think they eat only plants (especially the prized flowers and vegetables in your gardens). However, there are a number of "vicious" predators among the group known as the Gastropoda. Kellet's whelks prey on other snails. I have seen them munching away on the soft tissues of several species of top snails. They will also scavenge on dead critters. They use a long extension known as a proboscis, up to three times the length of the shell, with a hard radula to rasp flesh from their prey (living or dead). In the Great Cycle of Life (which I call the Mutual Eating Society) they are in turn munched on by starfish, octopus and fish like sheephead with strong crushing jaws.

Hmmm, speaking of sheephead and their powerful jaws, I was filming the whelk orgy (oopsm there's that nasty word) when I felt something bite me hard on the right cheek. Ouch! I quickly stopped my camera and looked over to see a 10" female sheephead staring at me. Now I've had the big male sheephead, Oscar, bite my fingers back in the days when I wore my "holy" gloves underwater. However, he was just testing to see if I was soft and chewy, and my bony fingers were not to his liking. This "lady" seemed determined to take my soft cheek tissue for her sustenance, and the bite definitely drew blood. I may need to wear one of those Sea Trek helmets next time I dive to protect my handsome face! But then some lady-go-divers might enjoy a tall tail of the fish that got away... with a piece of me!

© 2011 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Clusters of mating Kellet's whelks on the rocky reef and clusters of the egg capsules left behind.

This document maintained by Dr. Bill Bushing.
Material and images © 2011 Star Thrower Educational Multimedia