November 16th, 2011 by Marc AuMarc

Norman Island is an uninhabited island south of Tortola, and undoubtedly the best Extreme Shallow Snorkeling site we’ve been to in ages. A protected bay much beloved by pirates, it is also full of fish and the pelicans and brown boobies that love to eat them.

Our adventure began when we came onshore by dinghy to get the scuba tanks filled. Intending to take a quick snorkel while the tanks were filling, we discovered a wonderland full of huge schools of bait fish, pelicans diving almost on top of us and gigantic tarpon patrolling the two piers. Stingrays were abundant, often cruising in a foot of water near the shore, and a wide variety of reef fish were there, including beauties like the scrawled filefish. Needless to say, the tanks were filled long before we got back out of the water, and we immediately headed back to the boat to grab our cameras.

Back in the shallows with our photo and video gear, we explored the whole area again and probably would have never left if we didn’t have to. We actually didn’t even explore the nearby underwater caves. Although we didn’t find pirate treasure, we found a snorkeling paradise that must be revisited. Photos don’t do it justice, but here are a few. Did I mention the tarpon were huge? People arriving at the dinghy dock kept thinking they were sharks.

November 16th, 2011 by Marc AuMarc

Guana Island is a small island just north of Tortola, which allegedly has the greatest terrestrial biodiversity of any island its size in the Caribbean and possibly the world. We didn’t set foot on land, but we did get a couple chances to snorkel. On our first excursion we discovered some successfully transplanted elkhorn corals near the beach. As it turns out, these were done by a team including Graham Forrester, who we had the pleasure of meeting in Saba last year. You can read more about their study in this pdf. The corals we saw were doing very well and were quite large for three or four years of growth.

The next day we explored other parts of the bay and found a wide variety of sea life, including a greedy octopus who seemed to be trying to eat several mollusks at once. Stephen spotted a large southern stingray and I found a nurse shark and a snapper that was practically the size of a shark. Madam J, unfortunately, found a lionfish. The previous evening we’d seen lots of small fish jumping out of the water, and our observations while snorkeling confirmed that there were quite a few schools of small jacks who were probably responsible, attacking the baitfish and getting them to jump.

November 15th, 2011 by Marc AuMarc

The coverage of our recent expedition to the British Virgin Islands begins at the site of our arrival, The Baths in Virgin Gorda. This well-loved area is essentially a beach covered in gigantic boulders, creating a variety of grottoes and nooks both above and below the water line.

We explored both on foot and on snorkel, and there were plenty of extremely shallow areas full of life. Fish were abundant and tiny orange anemones were often clustered in shady areas and crevices. Madam J found a gorgeous underwater arch we were able to swim through, and nearby I discovered a small cave with an underwater entrance leading to an air-filled dome. Judging by the number of names and initials carved into the ceiling, I was not the first to discover it.

September 8th, 2011 by Marc AuMarc

Did I say manta ray? I meant EXTREME SHALLOW manta ray. Anyhow, I first saw it from our balcony, where it was circling (presumably feeding) in the shallow water just off the beach. A small crowd, mostly kids, had already been watching it for some time. Although the visibility was really bad, it was still amazing to snorkel with it, or just stand in the water and watch it cruise around. It didn’t seem bothered by us and would swim right up to us.

After maybe half-an-hour, I figured I might as well put my camera in its underwater housing and give it a shot. Unfortunately, the visibility was super bad, so mostly I ended up with photos of ghost manta ray. After another half-hour or so, it went out into the bay. If it’s the same manta that was seen near the Grand Case Beach Club a few weeks ago, though, perhaps it will be back.

Perhaps the best part was how excited everyone was to see it and pretty much everyone went out into the water check it out. One girl, who was probably about five years old, told me that she had lived in St. Martin her whole life and had never seen one, except in Finding Nemo.

September 5th, 2011 by Marc AuMarc

When the wind changed directions yesterday, it brought to Grand Case the sargassum that has been amassing on St. Martin’s eastern shores for several weeks. In the North Atlantic’s Sargasso Sea, this algae provides shelter for a variety of organisms, such as juvenile fish and invertebrates. So, even though the bay was rough and cloudy, we went out to investigate the floating patches of sargassum.

I found it was possible to find some shrimp amongst the sargassum, although it was tough to do while snorkeling. Instead, I developed another approach, grabbing clumps of sargassum and shaking them out over a plastic bowl. Using this method I was able to to find a variety of creatures, mostly shrimp of different sizes and colors. I also found a few small crabs, including one very strange looking larval crab.

Did they really come all the way from the Sargasso Sea? I’m sure some of the critters could have joined the floating caravan as it has travelled this way, but I would guess many or most of them are, like the sargassum, far from their normal home. Apparently there are a variety of shrimp from the genus Latreutes and others that are residents of the sargassum, often adapted in color and shape to be well camouflaged in that environment.

What is their fate? It would seem that they’re mostly doomed as their homes wash up on the beach. Even if they manage to stay in or get back to the water after their sargassum is gone they would make an easy meal with no place to hide. In the meantime, anyone with a bucket and a little patience can explore an ecosystem that’s traveled hundreds of miles to visit our island.

Below are some photos of crustaceans taken from sargassum, mostly a variety of shrimp. If you look closely, you can see eggs on the underside of some of the shrimp, and organs through their transparent shells.

September 1st, 2011 by Marc AuMarc

For a number of years, the ongoing spread of invasive lionfish in the Atlantic and Caribbean has been the hottest story in marine biology. The invasion has been unprecedented in its speed and impact, from one or more initial introductions probably in the early 1990s to their increasing range and ballooning populations today. Today, they can be found along the east coast of the US from North Carolina to Florida and in most of the Caribbean. In the future, that range may extend to the southern end of the Brazilian coastline.

As the problem has progressed, our ideas about how to address it have changed as well. However, it seems like the lionfish invasion is not only outpacing our efforts to control it, but also our thinking about the problem. As far back as 2003, the NOAA issued a report conceding that elimination of the lionfish was “nearly impossible.” Even back then it occupied much of the southeast US coast, in a wide variety of habitats and in surprisingly high numbers. Still, we held out hope that we could keep it from spreading or manage the population. As it reached each new area, we headed out with nets and spearguns hoping to keep it from becoming established only to fail every time.

To take a step back, humans don’t have a great track record of eradicating invasive species. I think we’ve done it a few times, mostly eradicating goats or rats on uninhabited islands with great effort and expense. The lionfish problem is many orders of magnitude greater. They reproduce quickly and can travel unrestricted throughout the Atlantic and Caribbean. Like many tropical fish, during their larval stage, they are thought to ride the open ocean currents for weeks before settling down. Only a small part of their habitat, shallow reefs visited by snorkelers and divers, is even accessible to humans. At best, eradication could only happen in the tiny sliver of habitat where humans are present and would easily be re-invaded by individuals from the next island or even just a few hundred meters away in deeper water.

To be fair, a typical lionfish plan also includes studying their impact on local ecosystems and raising awareness in the local population. These two goals are worthwhile, and they implicitly assume that lionfish are here to stay. Annual lionfish hunts and the recent push to drive interest in eating lionfish, on the other hand, get much more attention in the press and the public imagination. Biological control, such as attempts to “teach” grouper to eat lionfish are more plausible than going out to catch them all by hand, but at best would only adjust the eventual population equilibrium they reach.

Of course, I would love it if we could eradicate lionfish in the area, and I think it is admirable to give it a shot. At the same time, it seems pretty clear that it won’t work. I think that’s pretty hard to admit, but consensus is bound to move that direction. As we move in that way, the main question will be, how do we preserve marine ecosystems as best we can despite the presence of lionfish?

That’s a harder question to answer. More robust marine ecosystems will probably fare better, so expanding marine protected areas might help offset losses due to lionfish predation. Artificial reefs could increase the total available habitat for reef fish as well. Because small and juvenile fish are particularly vulnerable to lionfish predation, it may be worthwhile to create protected nursery areas. If I were more knowledgeable, I would probably have more or better ideas, but I’m sure those will come as the focus shifts from attempting to control lionfish to doing what we can to save the rest of the ecosystem. It won’t be easy, but at least it won’t be impossible.

Below are some photos taken while snorkeling in Grand Case Bay. There’s a lionfish in the piece of pipe, and the photo after that shows a lionfish marker placed at the site, which is used to make it easier for the marine reserve to find and capture the lionfish. Many of the other photos feature juvenile fish that don’t yet know how threatened they are.

June 9th, 2011 by Marc AuMarc

I’m not sure of the actual name of the hill, but the road near it is called Round Hill Road, so that’s how I’m referring to it. It’s the hill that rises up towards Mont O’Reilly from Grand Case, behind the Caribbean Queen pharmacy. I took a walk up there a few days ago and found quite a few interesting critters. I don’t have a lot to say about them at the moment, because I need to do some serious work to identify many of them. In general, the area is pretty lush for such a low hill and there’s quite a lot to be seen there. It also offers plenty of opportunities to get poked and scratched by a variety of thorny shrubs.

May 27th, 2011 by Marc AuMarc

Last week we had the privilege of joining some friends on their boat for the day, including a snorkel at Baie Longue near the end of the beach by Cupecoy. The sea floor in the area is predominantly sandy, with few rocks to provide a substrate for corals or a habitat for fish, but the water is often crystal clear. As you can see below, there was a large school of palometa which settled in beneath the boat as soon as we dropped anchor.

Although it’s fun to see a large school of fish, they are almost certainly there because they are fed, probably by boats who stop there to let their passengers snorkel. This is, of course, generally seen as a bad idea because it changes the behavior of the fish. In some cases, for example, fish may eat less of their normal food, thereby failing to fulfill their role in the local ecosystem. It also makes them more vulnerable to fishing, which for the palometa may be bad for those who eat them. Palometa that normally travel between the open ocean and the shallows may be more likely to develop higher levels of ciguatera toxin if they learn to stay in the shallows.

Anyhow, the snorkel was quite fun, and I was also able to find a peacock flounder and many juvenile grunts near a small patch of rock, as well as a young southern stingray.

April 25th, 2011 by Marc AuMarc

Yesterday afternoon I went on a quick expedition to the lagoon area off the north beach of Pinel with Pauline from the Réserve Naturelle. Our goal was to check the elkhorn corals to see if there were broken pieces suitable for transplanting. Elkhorn corals are both prone to breakage and often do well when transplanted.

At the large elkhorn we located we found a very interesting scene. The main colony was large and healthy. There were a couple pieces I had wedged into the dead coral substrate on an earlier visit as well as a number of other pieces on the sea floor. While a few of these were loose, many of them had managed to affix themselves and were growing in the areas down-current from the main colony. Most surprising was one particularly large branch that had affixed itself upside-down with the broken part at the top.

It was encouraging to see how well the coral was colonizing naturally with the broken pieces, but we also planned to visit the site regularly. Even though many pieces had successfully reattached, it is unclear what the percentage of successful reattachment is. It is possible that the dozen successes are just a small subset of the total number of broken pieces. A bit more ominous was the presence of a fair amount of algae in the lagoon, perhaps indicating an excess of nutrients that could be problematic for corals. More news to come!

April 25th, 2011 by Marc AuMarc

Little Key is a small islet that lies more or less along the ferry route to Pinel. Underwater, it has a nice, shallow reef on the side that faces away from St. Martin, making it worth the swim from Pinel for a little snorkeling as long as you’re careful about watching for boat traffic. Right now, the islet is also a roosting area for dozens of brown pelicans, the largest group I’ve seen on the island. Apparently this flock has been going back and forth between Little Key and Étang Chevrise near Orient Bay. I took a few photos while I was out there, but unfortunately didn’t notice a drop of water on my lens.