No, the title of this week's article doesn't refer to a circus act with Ringling Brothers. It is just another of those "must see" fish species that I was determined to locate while diving in Central America. Here on Catalina we are familiar with birds that swim (cormorants) and fish that fly (flying fish). Although the flying gurnard doesn't actually break the water's surface, it can be seen "flying" over the bottom with its elongated pectoral fins extended into formidable "wings."
Gurnards are members of their own family containing eight species, and are not related to flying fish. This species was known to Linnaeus, the father of the modern scientific naming system (genus and species), who described it in 1758 giving it the scientific name still used today. At least some names are stable in this era of rapidly changing corporate identities!
Our Lindblad Expeditions ship decided to visit tiny Coco Plum Caye in Belize one day. I was informed ahead of time that the diving there would be minimal at best since the depth was shallow and the bottom was largely turtle grass meadow and mangroves. Despite that, I was determined to take my video camera "down" to see what I could see. My dive actually was a combination dive and crawl since I had to cross a sandbar with only one foot of water over it. I don't know whether it was the laughing gull above, or our guests enjoying the bar facilities on land, but I was sure I heard expressions of amusement as I proceeded over the sandbar on all fours.
The "dive" was well worth it. I was videotaping a cushion starfish (the only place I ever saw one down there) feeding on turtle grass when something grabbed me and shook me. No, not a tiger shark (in 7 feet of water?)... it was our whale specialist Lisa trying to get my attention to look at a strange fish she had found. She pointed to it and there, camouflaged within the turtle grass, was my first (and only) flying gurnard. My camera started rolling immediately in case it had a take-off already scheduled.
This unusual fish ranges from 6-14" in length with a maximum of 18". Although only seen occasionally, they are found throughout the tropics and warmer waters from the Caribbean to West Africa and the Mediterranean as well as East Africa to Australia and Polynesia. On occasion they are even sighted in places like Nova Scotia. Preferred habitats include sandy bottom, coral rubble, shallow bays, estuaries and sea grass beds in shallow waters although they can be found down to depths of 300+ feet.
Crabs are the preferred food of flying gurnards. They look for them in grass meadows where crabs can be abundant. They also eat clams and small fish. Spines at the end of their huge pectoral fins allow these fish to "walk" along the bottom as they hunt. DeLoach and Humann report that the fish have modified ventral fins which can be used to turn over rocks when searching for food.
The individual I filmed actually looked quite different from ones I'd seen in fish identification books. In the books they were a light gray with brown spots. This individual had a base color of green with brightly colored blue spots and streaks. I learned from the ship's captain (a diver himself) that this color phase was common in shallower waters. Gurnards can change coloration to match their environment so this color pattern was undoubtedly an attempt (successful!) to camouflage itself in the sea grasses. It did have the characteristic enlarged pectoral fins which allow it to glide in the water, and are also extended to make it appear much larger to potential predators.
Given the presence of numerous sharp spines for defense, I can only guess how this species mates. I don't imagine there is much "cuddling" beforehand! Of course the ladies of our own species say that is common. The eggs hatch into planktonic larvae that disperse in the ocean currents. It is believed that gurnards found at deeper depths in open water originate from larvae that could not find suitable shallow habitats when they were ready to metamorphose into adults. The one I observed was much more fortunate, settling into an ideal habitat (until I disturbed it).
© 2004 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.
Flying gurnard in shallow sea grass habitat around
Coco Plum Caye, Belize: well camouflaged,
head region, swimming away without wings, close-up over sand.
This document maintained by
Dr. Bill Bushing.
Material © 2004 Star Thrower Educational Multimedia