Fish Mortality Study to be conducted March 27, 2007 at Lake Amistad

Tournament caught bass are released through the fish tube at Diablo East.
Tournament caught bass are released through the fish tube at Diablo East.

NPS Photo

Texas Parks and Wildlife Department Fisheries Biologists from across Texas will be converging on Lake Amistad this week-end to prepare for a mock black bass fishing tournament which will be held on Tuesday, March 27. The Fisheries Biologists, working in cooperation with the National Park Service, will be conducting a fish mortality study similar to the study they conducted on August 15, 2006 at Lake Amistad. Researchers have found that some black bass released after a bass tournament weigh-in suffer from what is known as a “delayed-mortality”. The bass appear to be perfectly healthy, and swim away in a normal fashion after being released, but die four to six days later. Concerns have been expressed that the National Park Service fish tube, which is used as a release mechanism for the tournament-caught bass, is contributing to this delayed fish mortality. This study is an attempt to prove or disprove these concerns regarding the fish tube. The intent of the fish tube was to provide a means to quickly release the tournament-caught fish back into the lake as soon after the fish were weighed in as possible. The fish tube acts essentially the same way as a water slide. One end of the fish tube is up in the parking lot where the fish tournament weigh-in scales are located. The fish is then put head-first into the tube, which is an eight-inch diameter PVC pipe, with water flowing into the tube from the top. The fish slides down the tube and right into the lake.
 
Catch and release boats, like this one used at the 2007 Elite Series tournament, are believed to increase the survival of tournament caught bass.
Catch and release boats, like this one used at the 2007 Elite Series tournament, are believed to increase the survival of tournament caught bass.

NPS Photo

During the up-coming fish mortality study on Tuesday, March 27, fishermen will hold a simulated bass tournament, and bring the fish back to the Diablo East boat ramp beginning around 2:30 pm. The fish will be broken into three groupings. The first group of fish will be weighed right at the dock and released immediately into a holding pen tied to the dock. The second group of fish will be transported in the live well of the boat, which will be trailered and hauled to the fish tube weigh-in location adjacent to the Diablo East Marina, which is how most tournament fish are transported. These fish will be weighed, put back into the boat live well, and transported back down to the boat ramp, where they will be released into the holding pens tied to the dock. This will simulate a second fish release procedure commonly used by tournament fishermen. The third group of fish will be transported in the same manner as the second group, but instead of being taken back down to the boat ramp for release, the fish in group three will be put into the fish tube. The fish will come out of the fish tube into a temporary holding pen at the foot of the fish tube. All three groups of fish will be marked by putting a small paper punch hole into one of the fins, and the fish will be transported into larger holding pens measuring 18 feet across and thirty-three feet deep which will be kept in a deep nearby cove. The fish will remain in these three large holding pens for the next six days, along with a fourth “control group” of fish that will be collected through a technique known as electro-shocking. Fisheries Biologists will monitor these three large holding pens for the next six days, recording any fish that die over the six day period. The hole in the fin of the dead fish will allow the biologists to determine which fish release technique was used.

Last updated: February 24, 2015

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