The concept of shifting baselines is an important one in reef ecology which basically describes how successive generations of researchers have their own ideas of what constitutes a healthy or a natural reef. Nowhere is this concept more important than on the heavily degraded reefs of the Caribbean whose coral populations were heavily degraded before they could be well documented.
For example, Acropora palmata elkhorn coral used to be so abundant that entire zones of the reef were called Palmata Zones and they were a serious hazard to ships of early explorers. Fast forward to this millenium, and there is practically no such place that has a true Palmata Zone as this species has been decimated over 99% of its range.
It’s a pity that Caribbean reefs experienced such extensive degradation at all, but also a shame that it happened before much of it could be documented so we know what has been lost. Thankfully, at least a handful of historic photographs from the 70s show how glorious Caribbean reefs used to be, with fields of corals that actually resemble and rival the dense coral growth of Indo-Pacific reefs.
These images of shallow and deeper corals reefs around Discovery Bay Jamaica by Professor Phil Dustan show fields of Elkhorn and Staghorn coral growing in close proximity, practically crowding each other. And in deeper water a similar picture is shown of possible plating Montasrea (Orbicella) annularis and luxurious stands of Agaricia.
We don’t know what is more disheartening, that these exquisite reefs have now been reduced to a rocky wasteland or that dense healthy coral reefs like these are all but completely gone from the Caribbean. We know that there are a few places left which harbor fairly healthy reefs with respectable coral cover but they don’t compare to the historic photos of these “old growth” coral reefs.
It’s not all bad news though, because we know that with a hands-on approach we can regrow the Acropora to an appreciable degree and Diadema urchins that clean the reef of algae cleaning the structure for coral colonization are making a comeback. Perhaps with closer management and by addressing various environmental issues we could see the reefs make a collective rebound but it will take at least a human generation for the baselines to shift in a positive direction. [Biosphere]
I’m so glad to see these photos. i snorkeled these reefs in the 1970s, and have a hard time describing them to divers today. i was in both the florida reef tract and Jamaica. The top photo looks just like what I remember from Florida. The elkhorn coral was in thickets or forests that ran along the reef crest as far as you could see.Acres of it. Like a very wide hedgerow growing by the side of a road in the english countryside. the picture must be from high tide. you had to be careful of the tides, because as the tide went out, the tops of the corals would surface, and you could get stuck, even as a snorkeler, like being trapped in a maze. sometimes you barely escaped by filling your lungs, sucking in your stomach and barely floating over the razor sharp tops. The waves would break on these coral tops if it was rough with waves and swell, so you could only snorkel in this zone if it was fairly calm. The elkhorn coral separated the fore reef from the back side of the reef. and the fish were nestled in all the shelves and crooks and holes provided by the elk horns! You had to remember where you crossed in order to get back if the tide ebbed. when the tide was up, fish fluttered above the reef like birds above a forest canopy. A passing shadow or bigger fish or a snorkeler would make them drop into the reef fronds as birds do with a passing hawk. The view up to the surface glittered with these movements like wind through autumn leaves.
I didnt see plate like coral as in the second photo. i didnt dive that deep, though I was certified. Not enough money!
The third photo reminds me of what i saw in Jamaica. There was a fringing reef that you could swim to, you didnt need a boat. Access through the reef would be afforded where there was a freshwater stream or an outfall pipe. That would make a break in the reef. There I saw more staghorn and elkhorn together like in the picture. The elkhorn grew closer to the surface, with the staghorn fringing it. you had to search for eels and different fish and look out for urchin spines sticking out from the coral.
im so grateful to my parents and professors for taking me to these places. I was SCUBA certified in 1968 and will keep diving as long as i can. but though i can return to those places, I can never return to those reefs. Im a diver from the Holocene, revisiting in the Anthropocene. They are the stuff of dreams, lost in shifting baselines.
I just wanted to tell you.
Maureen McConnell
Inverness FL