Texas A&M AgriLife Extension Service photo by Adam Russell.
Summer is beginning to heat up in Texas, and a Texas A&M AgriLife Extension Service expert advises landowners to start monitoring stocked ponds for oxygen depletion.
Landowners with stocked fish ponds should be aware of possible problems with oxygen depletion as hot, still days become more prevalent, said Dr. Billy Higginbotham, AgriLife Extension Service wildlife specialist.
From June to September, when the outside air is increasingly hot and pond water temperatures climb, are the time of year when oxygen depletions occur most for a variety of reasons, he said. Improper aquatic weed control, too many pounds of fish and the weather all contribute.
Higginbotham said typical ponds can sustain 1,000 pounds of fish per surface acre through summer months. When the environment is optimized and the pond owner stocks heavily, especially with channel and blue catfish, and feeds heavily with floating fish rations, that density level can be easily met and exceeded.
Oxygen production via photosynthesis can slow or stop after several hot, still, cloudy days, while fish can continue to use oxygen until it falls below 3 parts per million gallons, which stresses fish, Higginbotham said. Fish will then begin swimming to the surface to try to obtain enough oxygen to survive at the air-water interface.
Higginbotham recommends checking the pond at daybreak when oxygen levels are at their lowest daily levels. The pond owner should act quickly if fish are surfacing for air.
Larger fish are affected by low oxygen levels more than smaller fish, he said.
“It’s almost as if they are gasping for air at the air-water interface,” Higginbotham said. “That’s a clear sign of oxygen depletion, and the pond owner should act quickly to avoid a complete die-off of their fish.”
Pond owners can produce more oxygen for fish in various ways.
Backing a boat engine into the pond and circulating the water is one way to create more oxygen, Higginbotham said. Pond owners can also place a water pump in a shallow portion of the pond and spray water along the surface to circulate water along the air-water interface.
Once oxygen levels are restored, Higginbotham said pond owners should investigate the pond conditions that contributed to the depletion. He recommends thinning fish populations to reduce the pounds of fish the pond supports going into the mid-summer months.
Controlling aquatic vegetation can also contribute to oxygen depletion, Higginbotham said. Oxygen is removed from water as plant tissue decomposes, which can create a scenario where a die-off might occur.
Weed control efforts should be done gradually, about 15-20 percent of the vegetation at a time and with a week break between treatments, he said.
An aeration system is also a good investment for landowners to avoid problems or prevent future problems, Higginbotham said.
“Watch very carefully as we enter these still, cloudy days, the dog days of summer,” Higginbotham said. “Be mindful of oxygen depletion and the possibility of losing fish populations.”
Read the full AgriLife TODAY article for more information.
If you have any questions or would like more information,
As many Texans recover from recent flood damage, the Texas A&M AgriLife Extension Service has resources that can help.
The Texas Extension Disaster Education Network, or Texas EDEN, has science-based materials related to floods, and other emergencies and disasters at texashelp.tamu.edu. View the Texas EDEN Floods page for expert advice on flood recovery, and see these specific resources for additional information and for experts to contact:
- Can These Trees Be Saved? (ER-039): information on assessing tree damage after a storm or disaster
- When Your Trees Fail: Who Do You Call? (ER-040): a fact sheet on contacts who can help residents with tree care and removal
- After a Disaster: Recovery Safety Tips (ER-019): advice for avoiding health and safety issues during recovery efforts, including chainsaw safety and how to avoid mosquitos and snakes
- Onsite Wastewater Treatment Systems: Responding to Electrical Power Outages and Floods(ER-001): information on responding to a disaster’s effects on residential septic systems
- Salvaging Timber: Landowner Do’s and Don’ts (ER-037): a fact sheet helping landowners make decisions about damaged timber
Read this AgriLife TODAY article for more information about Texas EDEN and flood safety.
The National Forest Service Flooding and Its Effects on Trees page also has helpful information for landowners assessing and monitoring damaged trees. And, for resources on maintaining and protecting healthy riparian areas along streams and rivers, visit the Texas Water Resources Institute’s Texas Riparian and Stream Ecosystem Education Program at texasriparian.org.
Riparian Restoration on Farms and Ranches in Texas’
The Texas A&M AgriLife Extension Service has published a new resource for landowners and managers, “Riparian Restoration on Farms and Ranches in Texas.”
The new publication, which has been given the identification number WF-010, can be downloaded for free or purchased at $3 per hard copy through the AgriLife Bookstore, said Blake Alldredge, AgriLife Extension wildlife associate at College Station.
“This publication was developed for landowners in the Blackland Prairie and Post Oak Savannah ecoregions of Central and East Texas seeking information on how to properly manage their riparian areas. It’s important to note though, that many of the principles and practices discussed are applicable to other parts of the state as well,” he said.
The publication describes ways landowners can evaluate the condition of their riparian areas and then recommends techniques for restoring those sites, he said. Some of the techniques include reseeding native grasses and forbs, proper plant species selection, and proper grazing techniques and management along croplands. The basic monitoring methods used to maintain productivity are also explained.
The publication is a collaborative effort of AgriLife Extension’s wildlife and fisheries unit, the Texas Water Resources Institute and the U.S. Department of Agriculture Natural Resources Conservation Service.
The publication was developed as part of the Building Partnerships for Cooperative Conservation in the Trinity River Basin project managed by the Texas Water Resources Institute and funded by the Texas State Soil and Water Conservation Board through a Clean Water Act grant from the U.S. Environmental Protection Agency.
See the AgriLife TODAY news release here.
Join the Texas Riparian Association Listserv! The Riparian Listserv was created to encourage the exchange of information on riparian issues among the citizens of Texas. You do not need to be a member of TRA to subscribe. Notices about recent riparian research, conferences, training, and activities are posted, along with discussions on riparian related information and issues.
Instructions to Subscribe
Information on how to subscribe to the Riparian Listserv can be found at http://texasriparian.org/about-tra/listserv/, or you can go directly to the page at http://nrt.tamu.edu/courses/texas-riparian/ where you enter your contact information into the form to subscribe.