Dive Dry with Dr. Bill

#358: A Round and A Round and Another Round...

I've been doing a lot of night diving lately... certainly the most I've done in any year since I stopped taking lobster back in 1975. No, the economy hasn't forced me back into "bug collecting," I'm not that desperate... yet. I'm working on a new video tentatively titled "The Night Shift" about all the different critters and behaviors you can observe underwater at night compared to during the day. Of course a second reason is to escape all the students practicing their "bicycling" skills in Open Water SCUBA classes. Unfortunately a group found me last Saturday night as I was filming a young octopus in the dark. They decided to come close so they could see what Dr. Bill was filming... and stirred up so much sediment with their fins near the bottom that I couldn't find the octopus to continue. Good thing I'm a man of patience versus the other type of doctor who has patients (and income) instead.

I'll digress a bit further before finally getting to the core of this week's story. A few weeks ago, prior to the opening of lobster season, I was seeing a large number of bugs on the bottom in the dive park at night, and a healthy number of legal sized ones. Then, beginning opening night, I started seeing strange lurking shadows in small boats at the periphery of the dive park... and a few entering the water from the stairs late at night. This past weekend I heard from friends who own a mainland dive shop that they were coming over to the island for a wedding, and saw a group of divers ready to board the Express to return to the mainland. They had a large cooler, and when asked what was inside, the divers proudly said "lobster." When asked where they got them, they responded "The dive park at Casino Point." I'll leave it at that... for now, but you can bet I'll be revisiting this sad example in a future column.

On my latest night dive, following a great afternoon of music at JazzTrax (thanks Rob and Kathy), I found a green abalone out in the open. It's rare to see one of the succulent snails at all, much less out in the open, so I began filming it. All of a sudden a shadow flew across the abalone and it, and the camera, were struck simultaneously by a disc-shaped object. No, I hadn't found the long rumored underwater base for the UFOs seen off Catalina since the 1950s. This disc was that of a round stingray and I quickly turned the camera to follow it. I ended up following it with camera rolling for a good 10 minutes. Now that was quite a feat as the ray went through thick kelp, rammed into rocky reefs and swam from the sandy bottom to the top of the kelp canopy! It certainly made me earn the footage I shot. Do you realize how difficult it is to look through a camera viewfinder to keep your subject framed AND look out your other eye to spot rocky reefs or kelp rushing at you at 1-2 knots, all while in the dark?

I rarely see round stingrays in our waters so they are a rare treat to film. I do encounter them frequently on sandy bottoms in areas like La Jolla Shores. These small stingrays are the cause of most of the stings bathers and fishermen receive, but they are strictly defensive in nature. This is why bathers and shore divers are told to shuffle their feet as they walk in shallow water. I had no fear of becoming Steve "Irwinized" by this one as I followed it. The fish was simply out looking for munchies. For the smaller stingrays, worms, shrimp, crabs and amphipods are on the menu while the older ones prefer clams but will take the other entrees as well.

Another ray with a circular disk is the Pacific torpedo or electric ray. These are gray in color, larger (up to 4 1/2 feet in diameter) and have fatter tails with two dorsal fins on top. A dive friend of mine, the lovely (and very nice) Argentinean model Paula Marrama, was diving at the park this weekend with her boyfriend Conrad and friend Justin. They happened to encounter an electric ray and, not knowing what it was, Conrad and Justin touched it. When I explained what that fish actually was, Conrad said it was a "shocking" encounter.

In the course of my frantic chase, the stingray went head-long into some thick kelp. I had to stop and try to relocate it before I could resume filming. However, there was something a bit odd. Before hitting the kelp, the stingray had a normal tail. Afterwards it had NO tail... and therefore no stinger! Now that was truly inexplicable... how could the tail fall off just from bumping into a little kelp? When I returned home to edit the video footage, I discovered that the tailed stingray was a female and the tail-less one a male. I had actually filmed two different stingrays... and I saw two more just before I started my ascent back to the dive park stairs. I've heard reports from other divers that they are seeing them in the dive park during the day as well, so watch where you place your feet! I've had no reports from Avalon's beaches yet.

The round stingray (Urolophus halleri) is one of the very few species we see here in Catalina waters. They are known from Eureka to Panama but are rare north of central California. They are usually found at depths from the surface to about 70 feet over soft sand or mud bottoms. As the common name suggests, the disk is quite round in shape and may reach a diameter of 22 inches but most I see are in the 10-15 inch range. Their disk is light brown to dark gray in color with light spots that are often yellow. They have a long slender tail with a small caudal or tail fin at the end. Although the stinger is reported to be near the base of the tail, I generally see them about half way back on it.

Round stingrays are sexually mature at about 10 inches. During June the females move inshore from deeper water to mate with the males. After mating they return to depth, but are found back in the protected shallows in August and September when they spawn. Males are generally found in shallower water much of the year except winter when storms appear. The four inch young are born in litters averaging three but may have as many as eight according to Dr. Milton Love of the Love Lab at UCSB. They remain in very shallow water, less than 12 feet, until they reach 6-7 inches, then move into deeper water along more exposed coastlines. It is unlikely that bathers will encounter these rays in our waters during winter... but then it is rarer to have divers in our waters in the winter since the warm water wussies have opted to dive in the tropics! Of course I have dreams of the Philippines, the Red Sea and Abrolhas in Brazil on my Christmas list! And I've been a very good boy... I haven't had any choice!

© 2009 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM 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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Round stingray swimming in my video lights; tail-less male and tailed female.

This document maintained by Dr. Bill Bushing.
Material and images © 2009 Star Thrower Educational Multimedia