Remove Sea Turtles from Large Tank

Remove Sea Turtles from Large Tank

When I was transferred to run an aquarium in 1984, the staff on site had already put 7 loggerhead and Kemp's Ridley sea turtles into the new 40,000 gallon main tank. Most were brought in by shrimpers who had caught them in their nets. I have no idea why they decided to hold the turtles for a while or why they put them into the main tank. They all appeared healthy and free of obvious injuries. The turtles were already tearing the new main tank filter apart. At night they would try to wedge themselves under a tank decoration (fiberglass fake rocks or trawl board, etc.) or under the crushed coral substrate so they would be stable while resting or asleep. They were digging down to the screening holding up the crushed coral and tearing holes in the screen that allowed the crushed coral to fall to the base of the tank, causing "dead" spots in the crushed coral biological filter (water was no longer circulating through the pile of coral extending from the tank bottom to/or above the screen).

The Curator of the building requested I get the turtles out of the tank and release them back to the wild to stop further damage to the tank filter screen. This was a brand new tank but already had major damage to the undergravel filter. I was the new guy on the scene; this was a test to see if I could handle the job, and I knew it.

The staff that was already there before my transfer thought this was a big joke, because after putting the turtles in the tank they had not been able to catch them to remove them, and were at a loss at what to do.

I thought about it a little while, bringing together my experiences in catching/trapping animals over many years. I made up a plan that I thought might work:

---starve the turtles for a few days so they would be hungry.

---bait my 4 foot diameter hoop net with a blue crab tied to the center of the netting. (The hoop net consisted of a fiberglass hoop which had half inch mesh nylon netting attached to hoop, forming a bag about a foot deep from the hoop. Lines went from 3 points 120 degrees apart for about 3-4 feet, to one rope to pull with. I had previously used this net to catch bullminnows, crabs, grass shrimp, etc., off local piers. I had made the net to function like a very large blue crab drop net.)

---lower hoop net into tank, and pull fast if a turtle tried to eat on the crab, or got near to the center of the net.

We got holding tanks ready to receive the turtles. I got the staff ready to handle the turtles one morning about an hour before we were to open up to the public for viewing, etc.

I lowered the baited hoop net into the main tank for the first time. Shortly a sea turtle tried to eat the crab tied in the center of the netting of the hoop net. I pulled up and brought up a sea turtle in the net. Within half an hour I got all 7 of the turtles out of the tank. The Curator and staff were somewhat amazed. I made my point. We released them all later.

Unfortunately I had to nurse this tank along due to damage of the filter area for several years (until 1996, when repair was started) before we got funding and the contracts awarded for the repair. External rapid sand filters and large diatom filters were employed to give extra biological and mechanical filtration capacity to the tank; additional chemical filtration was accomplished by adding crushed charcoal to the diatom filters. Repair was finished in 1997, and that is another story. The 40,000 gallon tank went 13 years without a cleaning of the undergravel filter; it was one of the largest undergravel filter tanks in operation.

Adrian R. Lawler, Ph.D.,  (C) 2012 --