Saint Martin/Sint Maarten
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| Northeast corner of the Caribbean (Anguilla to St. Barts). St. Maarten is left of center. |
When I first starting thinking about which coral reefs
should be studied in the Caribbean, I realized the focus should be the reefs of
the eastern Caribbean known as the Antilles.
Since I’m starting in the north
and working to the south, my initial focus will be the islands of Anguilla and
St. Martin. We sailed to St. Martin
because it is a sailor’s paradise with sail lofts, and marine chandleries for buying
and fixing what we need for Alaria. So, we studied the coral reef there first....
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| Alaria in St. Maarten |
Sint Maarten
Sint Maarten and Saint Martin are two names for a small island
with an identity crisis. They reflect
the two nationalities (Dutch and French) that lay claim to this tiny 7 mile
diameter island.
The island has attractive rolling hills and moderately high
relief. However, the steeply sloping
shores leaves little room for coral reefs to develop. Corals are physiologically plants that need
to have good light and water motion to grow. Because of St. Maarten’s steep
slopes, there’s just not much space for extensive coral reef development.
Despite modest coral reef development, the Sint Maarten
government has worked hard to preserve what they have. There is no fishing within their marine
park. They have a federally -funded
Nature Foundation that patrols the park.
We worked with them to learn about the challenges to the island’s coral
reefs.
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| The Nature Foundation's Marine Park Patrol boat with Chief Marine Park Ranger, Etienne Lake and George Stoyle (our fish expert). |
My hosts were Tadzio Bervoets who is the Manager of the
Nature Foundation and Etieene Lake who is the Chief Marine Park Ranger. They took us to their reef sites via their
patrol boat.
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| Tadzio Bervoets, Manager of The Nature Foundation St. Maarten |
Coral Reefs of St.
Maarten
We asked Tadzio to take us to their most important
reefs. We survey all the reef sites in
the same way by quantifying the abundance of all coral species, seaweeds, and
other reef-dwellers (this was my task) as well as all reef fishes (this was
George’s task). The fish transects are
30 m long and 4 m wide in which George counts and records the body size of all
the important species of reef fishes.
Later this can be changed into biomass (or weight) per species per unit
area for the sake of comparison with other reefs and other islands.
The reefs Tadzio and Etieene took us to were coral assembles
on rock but not really coral reef ecosystems. There is almost no coral build up over the
rock outcrops. So, what does that tell
us?
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| St. Maarten's reefs with low coral cover over rocks with a scattering of seaweeds |
Coral reefs are the only ecosystem on planet Earth defined
by the rock habitat they create. Corals
calcify limestone so when the corals die, the limestone remains and over time
it builds up forming a distinct structure known as coral reefs. With the exception of bogs that accumulate
plant matter, coral reefs are unique by being defined by what they leave
behind. So coral reef ecosystems have a
measurable geological growth rate which is essentially how many meters of reef
rock they produce per thousand years.
The fastest growing coral reef was “clocked” growing 12 meters per
thousand years (or 12 millimeters per year).
That is breakneck speed … geologically speaking.
The St. Maarten reefs we studied mostly had thin veneers of
coral over bedrock. Coral cover ranged
between 2 and 20% of the reef surface.
Seaweed is relatively abundant except in areas where the long-spined sea
urchin Diadema thrived. Diadema
is a very effective herbivore capable of removing all but the calcareous
“coralline” algae in its grazing range
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| Seaweed carpet makes life hard for reef corals |
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| The long-spined sea urchin Diadema |
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| Diadema's lair. They stay in crevices during the day and much seaweed at night |
The seaweed covering the rocks is similar to most Caribbean
reefs. Seaweed can kill corals by
poisoning them and it can prevent baby corals from getting started on
reefs. So I watch for seaweed on all of
the coral reefs I study. Interestingly,
because the Diadema sea urchin can
mow algae down, where they are abundant, the corals do well.
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| Three Diadema with little seaweed except the limestone grazer resistant pink coralline algae (which is a good habitat for corals!) |
Reef fish in St. Maarten had been hunted for years by
spearfishing, hook and line and trap fishing.
In December of 2011 all fishing was banned from the marine park. This is a great step in the right direction
because reef fish grow very slowly and generally cannot be harvested
sustainably. However, Tadzio and Eiteene
told us that every week they find people fishing in the park. They get warned or arrested but it will take
the best part of a decade to see functional reef fish communities. What I found most encouraging is the “can-do”
attitude of the Nature Foundation trying to educate and improve the conditions
of the reefs of St. Maarten.
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| Alaria from the top of the mast (photo: Paul Calder... thankfully) |
Now onto Anguilla
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