Eagle Mountain Reservoir - 2004 Survey Report
Prepared by Thomas Hungerford and Raphael Brock
Inland Fisheries Division
District 2-D, Fort Worth, Texas
This is the authors' summary from a 32-page report. For a copy of the complete report, use the download link in the sidebar.
Eagle Mountain Reservoir was surveyed in 2004 using electrofishing and trap netting, and in 2005 using gill netting. A creel survey consisting of 18 days was conducted during the spring quarter of 2002 to assess angler tendencies. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Eagle Mountain Reservoir is an 8,504-acre impoundment constructed on the West Fork Trinity River by the Tarrant Regional Water District in 1954 for municipal and industrial purposes. The reservoir is located in northwest Fort Worth. A TXU Energy steam electric generating plant uses reservoir water for cooling. Operations at the electric plant have decreased in recent years. The reservoir is approximately 10 miles long and 3.5 miles wide (widest point), drains 1,970 square miles of watershed and has 200 miles of shoreline. Conservation pool elevation is 649 feet mean-sea-level and storage capacity is 19,460 acre-feet. Angler and boat access is fairly limited. The Texas Parks and Wildlife Department owns a tract of land that was proposed to be developed into a state park on the reservoir, although no development has occurred to date. There is only one handicap fishing pier on the reservoir. Fishery habitat consisted primarily of boat docks and bulkhead.
- Prey species: The electrofishing catch rate for gizzard shad was 437.3/hour is higher than the district average of 270.0/hour. The index of vulnerability (IOV; i.e., percentage of individual gizzard shad less than 8 inches total length thought to be vulnerable to largemouth bass predation) for 2004 was 80.8 which indicates a high percentage of gizzard is available for predators (DiCenzo et. al 1996). The 2004 threadfin shad electrofishing catch rate was 528.7/hour which is much higher than the district average of 204.0/hour. Bluegill and longear sunfish are the two principal sunfishes in Eagle Mountain and their electrofishing catch rates for 2004 were 264.0/hour and 143.3/hour, respectively. The district averages for bluegill and longear sunfish are 160.0/hour and 87.0/hour, respectively.
- Catfishes: The gill netting catch rate for blue catfish for 2005 was 7.9/net night which is much higher than the 2001 gill netting catch rate of 0.9/net night. The district average for blue catfish is 1.9/net night. Twenty five percent of the sample consisted of individuals greater than 20 inches. The population expansion is likely due to excellent reproduction and recruitment. The gill netting catch rate for channel catfish in 2005 (6.5/net night) was higher than the 2001 gill netting catch rate of 2.3/net night and was higher than the district average of 5.6/net night. Nearly half of all channel catfish sampled (43%) were above the legal length limit. Directed angling effort during the spring quarter of 2002 for channel catfish was 9.0% and angler catch rate was 0.3 fish per hour.
- White bass: The white bass gill netting catch rate for 2005 (6.1/net night) was higher than the gill netting catch rate in 2001 of 3.7/net night. The district average for white bass is 8.0/net night. The majority (77%) of fish sampled were below the minimum length limit of 10 inches. Directed effort of anglers surveyed between March 1 and May 31, 2002 for white bass was 17.7%. Approximately 0.56 hours/acre were spent on Eagle Mountain during that period, with an average catch rate of 1.4 fish/hour, and harvest rate of 0.4/hour.
- Black basses: Smallmouth bass were stocked in Eagle Mountain in 1999. Although smallmouth bass have never been collected in subsequent fall electrofishing surveys, a 4.15-pound smallmouth was caught by an angler in 2003. The 2004 electrofishing catch rate for spotted bass of 21.3/hour was lower than the district average of 25.0/hour. The sample was dominated by smaller fish with only one over 12 inches. Anglers were not specifically seeking spotted bass during the spring quarter creel survey in 2002. The largemouth bass electrofishing catch rate for 2004 was 116.0/hour which was nearly double the 2000 electrofishing catch rate of 64.9/hour. The 2004 catch rate is lower than the district average of 126.0/hour. Largemouth bass in Eagle Mountain reach legal size (14 inches) at age 2+. Florida largemouth bass alleles in Eagle Mountain have dropped from 45% in 2000 to 29% in 2004. This decrease likely reflects the stocking of 232,424 fingerling Florida bass in 2000. The RSD-12 of 49 indicates nearly half of fish over stock size (8 inches) were over 12 inches. Directed effort for largemouth bass during the spring 2002 creel survey was 55.6% and the catch rate was 0.7 fish/hour. Several bass tournaments were included in the survey.
- Crappies: Black crappie are present in Eagle Mountain in low abundance (2.2/net night). The trap netting catch rate for white crappie in 2004 was 3.7/net night which was similar to the 1998 (3.4/net night) and 2000 (3.2/net night), but much lower than the district average of 16.4/net night. The RSD-12 indicates the sample was dominated by small fish. Anglers surveyed during the spring 2002 creel survey directed only 1.8% of the effort towards white crappie at Eagle Mountain. White crappie were harvested at a rate of 0.3 fish per hour.
Based on current information, existing harvest regulations should be maintained on Eagle Mountain Reservoir. Access is limited due to the large amount of privately owned land surrounding the reservoir. The reservoir lacks good boat ramps. One management strategy will include possible improvement of existing ramps or construction of new ones. Because the reservoir has adequate habitat and forage, requests for the stocking of smallmouth bass will continue. A 4.15 pound smallmouth was caught in the fall of 2003 establishing a new waterbody record.
Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-30 Statewide Freshwater Fisheries Monitoring and Management Program