Mapping the South Texas Banks

Fins to the Left, Fins to the Right

Mark Schrope
Sep. 25 2012
Waves periodically covered the lower portholes in the bow.
Waves periodically covered the lower portholes in the bow.Mark Schrope

We finally found a major shipwreck. It’s in about 100 feet of water and it’s huge. I must say, though, the fact that it was sunk there on purpose a few years back, and that its location is well known, did dampen the excitement a touch.

Video fish survey step 1: Spot a fish (left to right, Liana Lerma, David Hicks, Jonathan Le)
Video fish survey step 1: Spot a fish (left to right, Liana Lerma, David Hicks, Jonathan Le)Mark Schrope

Mapping the wreck of the Texas Clipper, sunk as an artificial reef in 2007, was just a quick diversion during a day full of more mapping–instead of a planned ROV dive. Sadly, leaders had to scrub the dive because conditions have grown too windy and rough for safe launch and recovery of the vehicle.

But even without the ROV in the water, there’s still plenty of work to do. The University of Texas Brownville team–professor David Hicks and grad students Jonathan Le and Liana Lerma–has taken on the task of identifying and counting all the fish that appear in the hours and hours of ROV video collected so far.

Step 2: Figure out what it was. Repeat. Repeat. Repeat. Etc...
Step 2: Figure out what it was. Repeat. Repeat. Repeat. Etc…Mark Schrope

They’re working in Falkor’s bowels in a lounge with two portholes that, every minute or so, were completely covered by waves hitting the bow, making them look more like windows into a washing machine or an aquarium.

Comparing Banks

So far they’ve made it through the first two ROV dives and are seeing some patterns emerge. Baker Bank, our first dive location, had far more fish and of more species than Aransas Bank. Aransas did have a lot more red snapper, but that doesn’t say much because red snapper are more mobile and move from bank to bank, meaning we might just as easily have happened onto a large school at Baker.

A red snapper at Aransas Bank.
A red snapper at Aransas Bank.Schmidt Ocean Institute/Deep Sea Systems International

The smaller reef fish abundant at Baker are much more telling of overall diversity and possibly health because they tend to stay in confined areas. Aransas also had fewer soft corals and seemed to be more covered in silt, for reasons we can’t say.

Hicks, who is part of a team that regularly assesses marine life on that Texas Clipper artificial reef, much closer to shore and shallower, says fish life at the banks looks similar. Species like French angels and almaco jacks you might find at either spot.

But his group did see a number of reef species they’ve never spotted at the Clipper—like sunshinefish, green and blue as an adult but with a yellow back that looks like a sunrise as a juvenile, and the brown-striped tattler bass, among others.

Looking Back

It’s hard to compare numbers, but interestingly, what little information there is on fish at the banks—from about 40 years ago—suggests that the diversity is about the same. “That’s what I think is surprising,” says Hicks, “How often do you come back to something that much later and have it look relatively the same?”

Sunset approaching.
Sunset approaching.Mark Schrope

You can’t say with one quick snapshot glimpse, but the similarities could mean that these banks have fared well over the years. A possible explanation would be minimal fishing because the reefs are so far offshore. And the next load of dive video they’ll analyze is from Dream Bank, which is much further south and even more remote.

At Baker, the group also spotted a single lionfish, which certainly would not have happened 40 years ago. This beautiful poisonous fish is native to the Pacific but was accidentally introduced into the Atlantic more than a decade ago. Since then it’s spread rapidly through the Atlantic, Caribbean and Gulf of Mexico. Because it has no natural predators in these waters, it tends to outcompete other fish for food, causing multiple problems.

Weather reports can’t ever be fully trusted, but the forecast says conditions should calm back down tomorrow, and if so the ROV will be going in first thing. The next target is Mysterious Bank, another one never before seen by human eyes. I’ll let you know what’s there tomorrow night.

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