Lake Pleasant Striped Bass
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Technical Guidance Bulletin No. 11 – February 2008 Lake Pleasant Striped Bass STATE : Arizona STATE TRU S T GRANT : F14R STUDY DURATION : January 2004 – June 2007 PRE P ARED BY: Bill Stewart, Marianne Meding, Diana Rogers Research Branch Arizona Game and Fish Department Phoenix, Arizona AZFGD—Research Branch Technical Guidance Bulletin No. 11 Arizona Game and Fish Department Mission To conserve, enhance, and restore Arizona’s diverse wildlife resources and habitats through aggressive protection and management programs, and to provide wildlife resources and safe watercraft and off- highway vehicle recreation for the enjoyment, appreciation, and use by present and future generations. The Arizona Game and Fish Department prohibits discrimination on the basis of race, color, sex, national origin, age, or disability in its programs and activities. If anyone believes they have been discriminated against in any of AGFD’s programs or activities, including its employment practices, the individual may file a complaint alleging discrimination directly with AGFD Deputy Director, 5000 W. Carefree Highway, Phoenix, AZ 85086, (623) 236-7290 or U.S. Fish and Wildlife Service, 4040 N. Fairfax Dr., Ste. 130, Arlington, VA 22203. Persons with a disability may request a reasonable accommodation, such as a sign language interpreter, or this document in an alternative format, by contacting the AGFD Deputy Director, 5000 W. Carefree Hwy., Phoenix, AZ 85086, (623) 236-7290, or by calling TTY at 1-800-367-8939. Requests should be made as early as possible to allow sufficient time to arrange for accommodation. Suggested Citation: Stewart B.S., M.M. Meding, and D.R. Rogers. 2007. Lake Pleasant striped bass. Arizona Game and Fish Department, Research Branch, Technical Guidance Bulletin No. 11. Phoenix. 40 pp. AZFGD—Research Branch Technical Guidance Bulletin No. 11 INTRODUCTION is occurring within the lake, extirpation of striped bass from the system is unlikely, and lake Lake Pleasant has historically been regarded as managers will need to develop a plan that allows one of the premier largemouth bass (Micropteus for the continued prosperity of the largemouth salmoides) fisheries in Arizona. However, and white bass fisheries, while developing and the quality of the largemouth bass fishery has promoting a valuable striped bass fishery. decreased, resulting in low angler satisfaction and a general concern for the health of the To make the proper decisions for management fishery (Bryan and Kohagen 2003). The leading of the reservoir, the current status of the striped hypothesis for the cause of this decline is the bass population must be properly researched. We recent invasion of striped bass (Morone saxatilis), addressed the following objectives with a 3-year which may be responsible, in part, for the shift in evaluation of the striped bass fishery in Lake largemouth bass size structure through competition Pleasant: for resources and predation. i) Determine energetic requirements of striped Striped bass initially entered the Central Arizona bass and other pelagic predators in Lake Project (CAP) canal system as eggs or larvae, Pleasant to predict the impact on prey resources entrained in Colorado River water pumped from and to predict the potential for striped bass Lake Havasu. Results from a four-year canal study population growth in the future. in the late 1980’s indicated a growing population of adult striped bass and the potential for their ii) Determine seasonal spawning movements, reproduction in the canal would increase as habitat preferences and reproductive success favorable hydraulic operations evolved (Mueller and recruitment of striped bass in Lake Pleasant. 1989). Striped bass reproduction was expected to be limited due to heat induced stress and STUDY AREA subsequent mortality. Nevertheless, striped bass Lake Pleasant is a water storage reservoir located quickly found their way into Lake Pleasant soon approximately 50 km northwest of Phoenix after it was connected to the canal system in (Figure 1). The original dam was built in 1927 1992. Striped bass presumably entered Lake for the purpose of irrigation and water storage Pleasant as eggs or larvae through the Waddell for Maricopa Water District. Increasing demands Dam forebay. Preliminary results of an evaluation prompted the United States Congress to authorize of the Lake Pleasant fishery indicated striped the Bureau of Reclamation (USBR) to construct bass abundance was increasing; however, it was the Central Arizona Project (CAP) in 1968 for the unknown if the canal continued to act as the sole purpose of transporting water from the Colorado source of recruitment or whether striped bass River to Central Arizona to meet these increasing were successfully reproducing within the reservoir water demands. Lake Pleasant was the logical (Bryan and Kohagen 2003). location for water storage due to its proximity to the Phoenix metropolitan area, the greatest Lake Pleasant anglers and fishery managers are concentration for water demand in the state. Since concerned the striped bass population has become the storage capacity of Lake Pleasant was not established, and will eventually out compete the enough to meet CAP needs, USBR proposed the favored largemouth bass and white bass (Morone construction of the New Waddell Dam, which chrysops) fisheries by effectively eliminating the commenced in 1985 and was completed in 1992. primary prey source, threadfin shad (Dorosoma After the old dam was breached, surface area of petenense). Although studies in some reservoirs Lake Pleasant nearly tripled from 3,760 acres to have confirmed these fears (Hart 1978; Allen 9,970 acres, and storage capacity increased from and Roden 1978; Baker and Paulson 1983), 157, 000 to more than 1.1 million acre-feet. others have shown these predators can co-exist if properly managed (Combs 1982). If reproduction Water is pumped into and out of the reservoir 1 AZFGD—Research Branch Technical Guidance Bulletin No. 11 Figure 1. Lake Pleasant is located approximately 50 km northwest of Phoenix, Arizona. The CAP canal connects to Lake Pleasant at the south end of the reservoir, and the Agua Fria and several tributaries flow in from the north. Pipeline Canyon is considered to be the dividing line between the upper and lower basin. through the same intake structure located at the 1998). The lower basin is deep and makes up the dam. Water is typically pumped from the canal majority of the reservoir. Various fish surveys into the reservoir from November to April. The since the construction of the new Waddell Dam water elevation is maintained (at least 90% of have identified 21 species (Table 1). A little full pool) until water consumption exceeds what less than half of the species are sport fish with is available through the canal system alone, and largemouth and white bass identified as the most then water is pumped out of the reservoir to sought after species by anglers (Bryan 2005). meet downstream needs (D. Crosby, Personal communication). METHODS High water demand results in a substantial change TELEMETRY (up to 40 m.) in reservoir water elevation between Transplant Methods summer and fall/spring months. The Agua Fria River and several small tributaries supply seasonal Fifteen CTT 83-3-I (62 mm x 16mm, 22g) inputs to the upper portion of the reservoir. (Sonotronics, Inc. Tucson, AZ) temperature Because the upper basin is influenced by the Agua sensitive sonic transmitters with a 36-month life, Fria River and its various tributaries, it tends to were implanted into 15 striped bass between be more productive than the lower basin (Walker January 2005 and January 2006. Initial attempts to 2 AZFGD—Research Branch Technical Guidance Bulletin No. 11 Species Scientific Name January of 2006, whereby all fish were collected Yellow Bullhead Ameiurus natalis via angling. The use of the sodium bicarbonate Goldfish Carassius auratus as an anesthetic was discontinued and fish were Sonora Sucker Catostomus insignis released immediately following surgery. A portable Common Carp Cyprinus carpio surgical station was set up on a pontoon boat Red Shiner Cyprinus lutrensis and Arizona Game and Fish enlisted the help of Threadfin Shad Dorosoma petenense public anglers to catch striped bass and quickly Mosquitofish Gambusia affinis transport each fish to the surgical station. The fish Channel Catfish Ictalurus punctatus were measured (TL mm) and weighed (g) prior to Green Sunfish Lepomis cyanellus tag implantation and release. In total, 10 striped Bluegill Lepomis macrochirus bass were successfully tagged (one from the first Redear Sunfish Lepomis microlophus attempt and nine from the second attempt). Sunfish Hybrid Lepomis sp. Fish Tracking Inland Silverside Menidia beryllina Surveys were conducted bi-weekly from January- Largemouth Bass Micropterus salmoides May (spring) and September-December (fall) and White Bass Morone chrysops monthly from June-August (summer) using an Striped Bass Morone saxatilis ultrasonic receiver (Sonotronics model USR-96). Golden Shiner Notemigonus crysoleucas When a fish location was identified, the date, White Crappie Pomoxis annularis time, tag number, tag temperature, and global Black Crappie Pomoxis nigromaculatus positioning system (GPS) location of each fish Flathead Catfish Pylodictis olivaris was recorded. The varying pulse intervals emitted Tilapia Tilapia sp. by the transmitter identified tag temperature; as Table 1. List of species that have been identified at Lake tag temperature increased, pulse intervals also Pleasant from 1987-2006. In 2006, a new species to Arizona, inland silverside, was discovered. increased (Sonotronics, Inc. 2006). Mean monthly temperature was calculated for all fish during each survey for use in bioenergetics modeling. implant transmitters took place during early spring 2005. Striped bass were collected by angling LARVAL FI S H SURVEY S and gill netting in January, February and April Larval surveys were conducted from May 19, 2004 of 2005, and a total of 8 fish were tagged. Due to June 2, 2004 and March 16, 2005 to May 25, to Food and Drug Administration requirements 2005 to determine presence/absence of striped bass regarding the use of certain types of anesthesia on eggs and larvae.