Bubbles from the Naturalist Jerry's tank - by Jerry Ligon

February 2006: Biological phenomenon occurring on Bonaire that makes this island number one in fish diversity...

Recent Settler-Green Razorfish--Photo taken by Jim Platz on Bari, 8 Feburary, 2006

There is a biological phenomenon occurring here on Bonaire that makes this island number one in fish diversity in the entire Atlantic and Caribbean and it involves the prevailing winds and currents. One is always aware of the winds on Bonaire and the direction that it constantly blows from—SOUTHEAST. This creates a conveyor belt for larvae from the reefs on the coast of Venezuela that transport these larvae literally hundreds of miles from where their natal grounds are located. This not only transports fish larvae, but every creature that depends upon the coral reefs: coral, sponges, shellfish, lobsters, shrimp, etc.,—almost every reef creature. Also, the reefs of Bonaire are also having their recently born larvae transported NORTHWEST to potentially settle on other islands that are upwind from their natal grounds here on Bonaire. Only problem is that there are no islands until you encounter Jamaica, which is too distant from Bonaire for this transportation system to work going in the upwind direction. So, unless a weather system happens to spin the right direction and bring these larvae back to Bonaire for settlement, this transportation system works most efficiently only to bring new reef creatures to Bonaire from continental reefs. Bonaire, therefore is known as a sink and not a source for these planktonic larvae.

Having new-born that are able to get away from the same reef that has given their parents all the living essentials that they needed to survive and reproduce, allows the newly born, fragile creatures to get away from the many hungry mouths that exist on the reef that can easily consume and eliminate them, which obviously would cause each species to become extinct. Probably no other single factor distinguishes marine creatures from their terrestrial, freshwater counterparts.
World wide, of the approximately 100 families of bony fishes associated with coral reefs, only four plus a single species in a fifth family are known to lack a pelagic early life stage. Of those bony fish which we find in the Caribbean without pelagic life stages are the toadfish and brotula. Cozumel’s Splendid Toadfish is endemic to only that island, something you would expect if a fish does not have a pelagic, dispersal life stage when they are newly born.

Recent studies have indicated that this pelagic larval stage can last from 9 to well over 100 days, depending upon the species of fish, and obviously has a tremendous effect on geographical ranges of these fish. Also, coral reef fishes are highly fecund, particularly by terrestrial vertebrate standards and most estimates of annual egg production range from 10,000 to over 1,000,000 per female. However, this is coupled with mortality approaching 100%, the majority of which take place during the critical new-born stage, so any adaptation that favors, even slightly this life stage means a lot to survival of the species. Remember, this is applied to ALL reef creatures, not just reef fish. Almost all reef creatures wind up in the plankton stream or on the surface and are blown to new settlement sites primarily by the prevailing winds.

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