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New England Aquarium -- Central Wharf, Boston
Sanctuary's Deep Boulder Reefs Revealed in New England Aquarium Exhibit

How do you get aquarium-goers to want to visit an exhibit that features a pile of rocks? How do you keep them once they've arrived?

The New England Aquarium has been able to meet those challenges with a new Gulf of Maine exhibit that features the Stellwagen Bank National Marine Sanctuary - the centerpiece being an innovative bow-front tank showcasing a deep boulder reef.

In the darkened halls of the aquarium the voices of entranced children and astounded adults echo off the walls, while noses bump against the convex one-and-a-half-inch thick acrylic barrier that separates the visitors from the boulder reef inhabitants. Through the effects of special lighting and design, it appears that the reef extends far more deeply into the distance than in a typical tank.

Here wolffish rest in their dens, lobsters lurk among the rocks, and anemones extend their graceful tentacles into the cold currents of this simulated environment. These piled rocks are one of the many types of habitats in the sanctuary - a habitat filled with nooks and crannies, strange creatures and surprising colors. The exhibit offers viewers glimpses of an unimagined and fascinating marine world just off the Massachusetts shore.

"The boulder reef tank was one of our bigger remodeling jobs and has become the largest exhibit on our upper level," noted Billy Spitzer, vice president for exhibits and education at the aquarium. "It may not be quite as exotic as our sea dragon tank, but its size and scope make it stand out. We're really pleased with the responses we're getting from viewers," he said.

Installing a 4,220 gallon tank in a 40 year old building required a significant amount of infrastructure renovation, including new structural supports, piping and filtration. The quarter million dollar project was made possible by funding from a number of institutions, including the sanctuary and the National Marine Sanctuary Foundation.

"Working with a pile of rocks was a challenge," said aquarist Tony Davi, who was one of the initial proponents for the project in 2003 when the idea was raised about a sanctuary exhibit. Davi had come to the New England Aquarium from the Aquarium of the Americas in New Orleans, where he had shepherded an exhibit on the Flower Garden Banks National Marine Sanctuary. Familiar with the sanctuary program, Davi saw great possibilities in the aquarium's cold water tank wing.

"Not only did we have to get the tank to work right, but we had to get the right collection of animals together - to get interesting specimens that can cohabit in a small space," said Davi. He gave the example of sun stars and sea cucumbers, which show a predator-prey relationship in the wild (in the aquarium tank the sea cucumbers are placed on a higher level, out of reach of the voracious sea stars). "We definitely didn't want to put our goosefish in here - he would decimate our fish population in a matter of days," he added.

The tank designers and aquarists decided on a tiered effect that simulates a boulder field that extends outward, and settled on an initial mix of species that exhibit a variety of shapes, textures and colors. They worked with scientists from the National Undersea Research Center at the University of Connecticut, reviewing hours of videotape and still images from sanctuary research cruises to get the right feel and mix of animals.

"We settled on several key species to start, and will be adding additional animals as the tank becomes more stable," said Davi. The first inhabitants of the tank include frilled and northern red anemones, smooth and spiny sunstars, horse mussels, and redfish, animals that have had good success in aquariums. Other residents include sea cucumbers, Atlantic cod, hermit crabs, and lobsters (including the aquarium's new light blue specimen).

"Unlike coral reefs, rocky reefs in northern waters do not have a strong public image. Most people think of northern seafloor environments, as not only cold, but brown and boring," said Brian Nelson, another aquarist with the aquarium. But he notes that that impression is unjustified. "Like coral reefs, the deep boulder reefs offer complex three-dimensional structure," he said, pointing out that the rocks provide dens for fish, hard substrate for benthic invertebrates, and protective barriers for a variety of species.

The new tank and its population of cold water species required more water flow, more penetrations (openings through which water can flow into the tank), and more current (the speed of the water flowing through the tank). "We wanted to make the exhibit as large as possible, with as much water flow as could be generated by the system," said Nelson. "The investment in generating the current is almost as great as is used in keeping the tank clean. We definitely pushed the envelope here, but our initial results have been great."

One indicator of tank success, according to the aquarists is the happy state of the anemones. "You normally don't see the tentacles of these animals extended as fully or for as long a time as these specimens have been showing," said Nelson. "The strong currents are continuously sweeping food particles their way - part of the special chum or 'chowder' that continuously enters the tank through a drip feeder." He notes that larger food particles are batch fed to larger species in the tank during the middle of the day.

The life support systems for the tank include mechanical filtration for particulates, biological filters for ammonia, chemical filters for skimming of proteins and carbon (from fish food and bodily processes), and disinfection with an ultraviolet filter. The water in the tank turns over four times an hour, with two pumps used for life support, and an additional two pumps devoted to creating current. The New England Aquarium filters local seawater from Boston Harbor to fill its tanks, rather than create artificial seawater.

The specimens in the deep boulder reef tank were collected from waters off Eastport, Maine. Although the water depths are shallower than in the sanctuary, the more northern location provides a variety of species equivalent to what is found in the deeper sanctuary. "Rather than dive the 75 to 120 feet necessary at Stellwagen Bank, we could spend a lot more time in the 20 to 30 foot depths near the coast," said Davi. The initial collecting trip included baskets of anemones and some 50 redfish - animals that could survive an extended period in holding tanks until the main tank was completed. Plans call for additional collecting trips to more fully populate the tank with representative species, many of which are more delicate and require a stable environment. Nelson noted that future trips will target stalked tunicates and small wolffish, as well as additional fish, crabs, and sea stars.

"We're extremely pleased with the appearance and functioning of the new boulder tank right now," said Spitzer, "but we're even more optimistic about its potential. As the initial animals take hold and get established, and as we add to the community, we will probably find that this becomes one of the most dynamic and exciting displays at the aquarium. We're looking forward to its growth and development."

In addition to the boulder reef exhibit, the aquarium has also renovated its former Georges Bank tank as a second Stellwagen Bank tank. Here, Atlantic cod, pollock, winter flounder, skates, and other demersal fish swim in a simulated sand/gravel environment. Additional tanks feature Gulf of Maine species that can also be found in the sanctuary. For aquarium goers who are more attuned to video images than live specimens, the sanctuary exhibit also includes a controllable video loop (action can be slowed or sped up) that showcases sanctuary natural and cultural resources, including scenes from the wreck of the passenger steamship Portland. The sanctuary and Gulf of Maine wing is part of the aquarium's regular exhibit space; there is no additional charge to view these displays beyond normal aquarium admission fees.



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