Dive Dry with Dr. Bill

#638: Barry Who? The Barramundi of Course!

I had the opportunity to spend a lot of time with birders when I worked on the Lindblad Expeditions/National Geographic eco-cruise ships in the Sea of Cortez, Belize and Honduras. Some were very interested in learning everything they could about a number of different bird species in the regions we traveled through, and were quite knowledgeable. I've never had much interest in birds unless their intentions were good... meaning that they could be seen on the water like Pelicans and even seagulls, or under the surface like cormorants.

Some bird enthusiasts reminded me of the collector mentality. If you've read John Fowles' book The Collector you probably know what I mean. This variant of bird watcher seems bent on chalking up as many species as they can within their lifetime. See it once, or even better get a picture of it, and it's checked off your list and on to the next species. Many of these sometimes obnoxious ornithologists don't seem to take the time to learn more in-depth about the birds they see. It's all about the numbers... just like when Roger Maris broke Babe Ruth's home run record (sorry, that's ancient history).

Underwater imagers and scientists often have certain species on their lists, too. I know I do. But, as I hope you've learned from reading my columns over the years, I like to learn as much as I can about each critter's life history. I also want to understand its role in the ecosystem within which it exists. If you go to a party full of people you don't know, your host may have thoughtfully given each guest a name tag. But most people wouldn't stop there... just reading the name tag and moving on. A truly interested person would stop and talk to the people he found intriguing and get to know a lot more about them than just their name. Of course there may be a few guests who you'd be happy not to even know their names!

One species I've been intrigued by for the past 20 or more years is the barramundi (Cromileptes altivelis). Recent studies using molecular genetics suggest the species should be known scientifically as Epinephelus altivelis. However, by the time I memorize the new name, they will probably call it something else. They are also known by the common names humpback grouper, polka dot grouper, panther grouper, pantherfish and barramundi cod but they are actually members of the sea bass family Serranidae They are found in the western Pacific and eastern Indian Oceans.

My first opportunity to find one was in Australia, but I don't remember actually seeing one. While in Palau recently I was surprised to come across not one, but several of them at various dive sites. Its body shape, rather unusual for a sea bass, distinguishes it from most other fish. It is laterally compressed, that is from side-to-side, and slopes upward behind the head to a high peak. It has an elongated jaw which is also somewhat distinctive. Body coloration varies from gray to beige with variable sized blotches along with dark black spots. Adults may reach more than two feet in length. The young are white in color with round black spots and usually swim with their heads pointing down.

So what type of munchies does this species prefer on its plate? Apparently fish and crustaceans are among its favorite menu items. I could live with that myself! Their feeding strategy is that of an ambush predator They sit still and wait for potential prey to approach, then lunge out to grab them. Scientists believe that the polka dot pattern on the body breaks up the shape so the victim doesn't see the predator's full size.

Barramundi are generally solitary and live close to the bottom rather than out in mid water. I did see one swimming out in the open over a coral reef, but the other two I observed were tucked into hiding places that made it a little difficult to film them. But, of course, Dr. Bill persevered. They will defend their territory against others, sometimes aggressively, although they shy away from divers. When these sea bass "get the urge," they do abandon their solitary ways and look for a potential mate. The female lays her eggs and the males fertilize them outside her body. Neither parent guards the eggs or young. I was interested to read that, like wrasses, the barramundi can change sex from female to male. Smart girl (just kidding, ladies!!). Usually it is the dominant female that makes this transition.

Sadly this unique species is considered threatened by the IUCN (International Union for the Conservation of Nature). They are naturally somewhat rare, but their status is in part due to exploitation of the species for live food markets and the aquarium trade. I was deeply concerned when I did my research and found an Australian seafood web page touting "the sweet flesh of this sea bass" and referring to it as "the sustainable seabass" and "Australia's favorite fish." Fortunately they were referring to an entirely different species that is also called barramundi and were raising it through aquaculture... another problem in using common names for a species. There are hatcheries that raise the fish I'm writing about, but they are not destined to increase the wild population. Instead these fish go largely to the aquarium trade. Oh, and if you happen to buy a little tyke for your home aquarium, it had better be a big tank. If it reaches 2+ feet in length, your 10 gallon aquarium won't be enough!

© 2015 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. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). 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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The barramundi and a small wrasse (arrow) cleaning it.

This document maintained by Dr. Bill Bushing.
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