As employees prepared this week for the opening weekend of Cabela’s, a giant outdoor outfitter off Maine Turnpike exit 42, Gorham resident Jim Pellerin will be doing his part to make sure fish will be healthy in the store’s 1,000-gallon trout pond and 10,000-gallon aquarium.

The 130,000-square-foot store is expected to create 700 new jobs, and some of them, like Pellerin’s, require expertise that goes beyond experience in retail, particularly those connected with the store’s elaborate wildlife dioramas, pond and aquarium.

After months of preparation, Cabela’s opens its 130,000-square-foot Scarborough store Thursday. The store is hosting an invitation-only opening from 2-4:15 p.m., followed by a public opening ceremony at 5 that will be attended by state and local officials. Cabela’s, which calls itself the world’s foremost outfitter of hunting, fishing and outdoor gear, is located on Haigis Parkway.

Visitors to Cabela’s Thursday will be among the first to view the new store’s prized centerpiece – a 25-foot-tall mountain ornamented with stuffed mounts of the 27 big-game species found in North America, and a stream emptying into a pond that holds three species of trout and the third-largest moose shot in Maine history.

Preparing the dioramas, pond and aquarium has presented a few logistical challenges. Deciding to put the historic moose – one of five stuffed moose in the store – in the water, for example, required figuring out how to protect the submerged legs from the water and the trout. Encasing the submerged portion of the legs in silicone proved to be the answer.

Cabela’s called on Pellerin to help get bacteria in the aquarium to levels that were healthy for the fish. An assistant regional fishery biologist with the Maine Department of Inland Fisheries and Wildlife, Pellerin once worked as a curator at the former Maine Aquarium in Saco.

“They were having some problems with the tank, initially, and I have some background with the work. So I just went down and talked to them, told them what I thought. Then they proposed that I work part time. I wasn’t looking for a job,” said Pellerin.

Since then, Pellerin has managed the installation and operation of four state-of-the-art “life-support systems” that control the store’s 10,000-gallon aquarium, 1,000-gallon trout pond and stream, a 500-gallon “hospital tank” to quarantine diseased fish, and a 500-gallon tank to hold shiners to sell and use as bait.

“Cabela’s spared no expense. The filtration system is top-notch, there are dual pumps, backup control. If you need to do maintenance on something, the system still functions,” said Pellerin.

However, establishing the multi-faceted and advanced system required expert assistance. “With any new tank, there is a break-in period,” said Pellerin.

This break-in process has involved more than adding chemicals or changing filters, however. While some harmful bacteria is eliminated or broken down by the filtration system, “You need to get some beneficial bacteria to form and condition the tank, growing to a level that can support the amount of fish,” said Pellerin.

The tanks contain whiffle-ball-like “bacteria balls,” providing surfaces for two species of “good” bacteria that detoxify the ammonia from fish excretions into nitrate to colonize. As this conversion requires multiple steps, however, fish and other organic items that might provide habitat or food for bacteria must be added at a slow and cautious rate to maintain an appropriate balance of chemicals.

While the trout stream has stabilized at its peak capacity, or “load,” the aquarium is not quite maximized at its capacity of 125 pounds of fish. In addition to its greater size, this system is further complicated by containing multiple species of fish that are native to Maine, including brown, brook and rainbow trout, landlocked Atlantic salmon, largemouth bass, yellow perch, American eel, pickerel and pumpkin-seed sunfish. All of these species require a similar but narrow range of water conditions, limiting the possible extent of temperature or chemical fluctuations in the tank

To monitor the water, Pellerin visits the store at least two or three times a week. Every day, the water quality in the pond and aquarium are tested for ammonia, pH level, nitrates and temperature and 25 percent of the water volume is replaced in order to ensure optimal conditions.

Eventually, Pellerin anticipates the time commitment will decrease as store staffers assume routine care for the fish and tanks. He will continue to check for a balanced population and add fish or habitat as necessary, but he says that the system is primarily self-monitoring.

“Once the system is conditioned, it will require very little maintenance,” he said. “As opposed to daily testing, water changing, adding chemicals, none of it will be necessary as frequently as it is now. It will be less stressful when we get to that point.”

As employees prepared this week for the opening weekend of Cabela’s, a giant outdoor outfitter off Maine Turnpike exit 42, Gorham resident Jim Pellerin will be doing his part to make sure fish will be healthy in the store’s 1,000-gallon trout pond and 10,000-gallon aquarium.

The 130,000-square-foot store is expected to create 700 new jobs, and some of them, like Pellerin’s, require expertise that goes beyond experience in retail, particularly those connected with the store’s elaborate wildlife dioramas, pond and aquarium.

After months of preparation, Cabela’s opens its 130,000-square-foot Scarborough store Thursday. The store is hosting an invitation-only opening from 2-4:15 p.m., followed by a public opening ceremony at 5 that will be attended by state and local officials. Cabela’s, which calls itself the world’s foremost outfitter of hunting, fishing and outdoor gear, is located on Haigis Parkway.

Visitors to Cabela’s Thursday will be among the first to view the new store’s prized centerpiece – a 25-foot-tall mountain ornamented with stuffed mounts of the 27 big-game species found in North America, and a stream emptying into a pond that holds three species of trout and the third-largest moose shot in Maine history.

Preparing the dioramas, pond and aquarium has presented a few logistical challenges. Deciding to put the historic moose – one of five stuffed moose in the store – in the water, for example, required figuring out how to protect the submerged legs from the water and the trout. Encasing the submerged portion of the legs in silicone proved to be the answer.

Cabela’s called on Pellerin to help get bacteria in the aquarium to levels that were healthy for the fish. An assistant regional fishery biologist with the Maine Department of Inland Fisheries and Wildlife, Pellerin once worked as a curator at the former Maine Aquarium in Saco.

“They were having some problems with the tank, initially, and I have some background with the work. So I just went down and talked to them, told them what I thought. Then they proposed that I work part time. I wasn’t looking for a job,” said Pellerin.

Since then, Pellerin has managed the installation and operation of four state-of-the-art “life-support systems” that control the store’s 10,000-gallon aquarium, 1,000-gallon trout pond and stream, a 500-gallon “hospital tank” to quarantine diseased fish, and a 500-gallon tank to hold shiners to sell and use as bait.

“Cabela’s spared no expense. The filtration system is top-notch, there are dual pumps, backup control. If you need to do maintenance on something, the system still functions,” said Pellerin.

However, establishing the multi-faceted and advanced system required expert assistance. “With any new tank, there is a break-in period,” said Pellerin.

This break-in process has involved more than adding chemicals or changing filters, however. While some harmful bacteria is eliminated or broken down by the filtration system, “You need to get some beneficial bacteria to form and condition the tank, growing to a level that can support the amount of fish,” said Pellerin.

The tanks contain whiffle-ball-like “bacteria balls,” providing surfaces for two species of “good” bacteria that detoxify the ammonia from fish excretions into nitrate to colonize. As this conversion requires multiple steps, however, fish and other organic items that might provide habitat or food for bacteria must be added at a slow and cautious rate to maintain an appropriate balance of chemicals.

While the trout stream has stabilized at its peak capacity, or “load,” the aquarium is not quite maximized at its capacity of 125 pounds of fish. In addition to its greater size, this system is further complicated by containing multiple species of fish that are native to Maine, including brown, brook and rainbow trout, landlocked Atlantic salmon, largemouth bass, yellow perch, American eel, pickerel and pumpkin-seed sunfish. All of these species require a similar but narrow range of water conditions, limiting the possible extent of temperature or chemical fluctuations in the tank

To monitor the water, Pellerin visits the store at least two or three times a week. Every day, the water quality in the pond and aquarium are tested for ammonia, pH level, nitrates and temperature and 25 percent of the water volume is replaced in order to ensure optimal conditions.

Eventually, Pellerin anticipates the time commitment will decrease as store staffers assume routine care for the fish and tanks. He will continue to check for a balanced population and add fish or habitat as necessary, but he says that the system is primarily self-monitoring.

“Once the system is conditioned, it will require very little maintenance,” he said. “As opposed to daily testing, water changing, adding chemicals, none of it will be necessary as frequently as it is now. It will be less stressful when we get to that point.”