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Big Sam at Risk
ATHENS, Texas — Over 100 acres of giant salvinia was found in the Angelina River north of Sam Rayburn Reservoir on Tuesday, October 13, 2009. Acting with the help of a waterfowl hunter, Texas Parks and Wildlife Department (TPWD) personnel investigated and identified the plants in a backwater area called Estes Lake approximately 10 miles upstream from Marion Ferry and Kingtown, in Nacogdoches County. An annual vegetation survey conducted by airplane last month did not detect the infestation since the survey does not include the Angelina River above Kingtown. The infestation had apparently been contained by shallow water and dense brush perhaps for a year or more. Low water levels help contain the infestation but recent rains may force the infestation south towards the main portion of the reservoir. Additional surveys are being conducted to define the southern extent of the infestation and determine if the infestation has reached the river channel.
Giant salvinia is highly mobile. The Five Fingers boat ramp on Sam Rayburn recently dodged an introduction of giant salvinia for the second time this year. Thanks to the vigilance of a concerned angler and hs willingness to help, the area around the boat ramp was cleaned of all visible salvinia before it could float away and colonize new areas. A second infestation of giant salvinia was found on Lake O’ the Pines in September. The infestation at the Overlook Park boat ramp reached approximately 1 acre in size before being detected by TPWD IF District 3A personnel. The area was quickly contained by oil-spill booms.
Arguably the most problematic aquatic vegetation in Texas, giant salvinia has been present in Texas over 10 years. Giant salvinia was first discovered on Toledo Bend in 1998 and before long reached epidemic proportions. A small but persistent infestation remains behind containment booms in Coleman Creek on Sam Rayburn while a highly mobile population seems determined to evade all control efforts on B.A Steinhagen. The fate of Caddo Lake is, at best, uncertain due to the expansion of giant salvinia.
This free floating aquatic fern is capable of doubling the area it occupies in as little as 5 days and can quickly cover the entire surface of reservoirs and ponds. In protected coves, "mats" of giant salvinia up to 2 feet thick disrupt ecosystems and render the water unsuitable for boating and fishing. A single plant clinging to a boat, trailer, duck decoy or fishing equipment can result in a new infestation. Giant salvinia is now firmly established in 11 Texas reservoirs.
While the success of control strategies in East Texas ebb and flow depending on weather and available funding, early detection and aggressive removal of giant salvinia has proven successful on several reservoirs. Physical removal of all vegetation has proven the only immediate and permanent solution to new infestations but is simply not possible in some cases.
TPWD personnel have discovered and removed potential infestations on Lake Pinkston, Lake Murvaul, Lake Palestine, Brandy Branch, Clear Lake, and Lake-O-the-Pines. Effective containment and immediate removal of giant salvinia found at boat ramps on these reservoirs potentially saved controlling authorities thousands of dollars in control costs.
Partnerships between state agencies, controlling authorities, and involved shareholders will be critical to prevent and control new infestations, but partnerships alone are not enough. Although localized transport may occur by natural means, most new infestations are the result of boat trailer transport. Plants clinging to boat trailers or other equipment are deposited in new locations and quickly establish new colonies.
In spite of the fact their transport is illegal; plants are finding their way to new reservoirs every year. Boaters discovered with giant salvinia or other prohibited vegetation on trailers can be fined up to $500 per plant.
Where will it show up next and who will be responsible?
Any report of suspicious vegetation is investigated immediately. Infested boat ramps should be reported to the controlling authority and TPWD. If giant salvinia is present in the reservoir, all equipment should be inspected and cleaned of any vegetation before leaving the boat ramp. While the prevention of new infestations may be the direct responsibility of those who pull boat trailers from one lake to another, everyone can play an active role in preventing the spread of invasive aquatic species.
Help protect your natural resources.
- Be aware of aquatic vegetation
- Learn to identify invasive species
- Report suspicious vegetation
- Encourage everyone you know to do the same.
More information on giant salvinia can be found at: http://www.nature.org/initiatives/invasivespecies/features/art8866.html or: http://aquaplant.tamu.edu/database/floating_plants/giant_salvinia.htm
To report possible sightings of giant salvinia please contact: Howard Elder, Texas Parks & Wildlife Department, Aquatic Habitat Biologist, (409) 384-9965, Howard.Elder@tpwd.texas.gov or Christopher Moret, Texas Parks & Wildlife Department, Aquatic Habitat Biologist, (409) 384-9965, Chris.Moret@tpwd.texas.gov
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