Dive Dry with Dr. Bill

010: Bat Ray

I certainly am not the best diver or even underwater videographer on Catalina (much less the world) but I do believe in the Babe Ruth philosophy of underwater imaging. We all know the "Babe" was once the home run king of baseball, but fewer people know he also set records for strikeouts. Under my philosophy, if you dive enough times and carry a video camera on each dive, you're bound to collect some good images... and "strike out" many times as well.

Conditions in the Dive Park this weekend suggested nothing but strikes... visibility above 30 feet was poor and there was a rather strong swell from a tropical storm off Mexico. However it was also warm and I needed to cool off so I grabbed my gear and headed down the hill. I'm glad I did. Once out in the deeper water I hit home runs twice... once with a large bat ray and then again with a very large California halibut.

Bat rays are a special treat... they truly are incredible to watch as they swim (or is it fly?) through the water column. Swimming in the open is more common at night. During the day bat rays are often on the bottom partially buried in the sand or mud. The one I encountered was even more interesting due to an entourage of jack mackerel following closely behind it. I have observed jack mackerel doing the same thing with soupfin sharks and black sea bass.

Bat rays are closely related to the sharks. Both have "skeletons" made of cartilage rather than bone. Bat rays are common throughout California and may be found off Baja and in the Gulf of California to the south, and occasionally Oregon to the north. They tend to frequent flat sand or mud bottom habitats, and are also found in kelp beds, but are most active at night. These fish may reach wingspans up to six feet and weigh over 200 pounds. Bat rays have one to three stinging spines located at the base of the tail which can inflict a painful wound, especially if stepped on in shallow water.

Bat rays have flat, grinding teeth used to crush clams and other shellfish found in the substrate. In fact the first part of its scientific name, Meliobatis, means "grinder ray." They also feed on crabs, snails, shrimp, worms, fish, and even abalone (if they can find them), often hovering over the bottom flapping their "wings" or pectoral fins to expose potential food beneath the soft sand or mud. Back in my days at the old Toyon school, we would catch and eat bat rays (they were much better than most of the kitchen's food!). Dishonest fish markets would sometimes cut the flesh out of the bat ray's wings and sell them as higher-priced "scallops."

Bat rays come inshore during summer to give birth and breed, then disperse in fall and winter. I generally notice them in the Dive Park beginning in late May or June. Females tend to live longer (up to 24 years) and grow faster and bigger than males. The one I observed was most likely a female about 12 years old and four feet wide. The female carries the young rays inside her body for 9-12 months and the 9-12" babies emerge live. A woman diver I met earlier this summer actually observed a female bat ray giving live birth in the Dive Park. Guess it was her turn to hit a home run... I struck out that day.

© 2003 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.

Image caption: Bat ray swimming through Casino Point Dive Park

This document maintained by Dr. Bill Bushing.
Material © 2003 Star Thrower Educational Multimedia