CDFW Contacts: Jim Erdman
Since 1996 Bishop Field Office staff have been restoring habitat for native frog populations in the Eastern Sierra. In response to the observed decline of the Sierra Nevada yellow-legged frog (Rana sierrae), CDFW initiated several actions to meet the state's responsibility to manage wildlife and their habitats for multiple uses. The two most important actions were 1) to temporarily suspend non-native fish stocking in high mountain lakes and 2) to initiate the High Mountain Lakes Project (HML) which is an effort to inventory the aquatic vertebrate species (fish and amphibians) and their habitat between 1,370 to 3,660 meters (4,500 to 12,000 feet) in the Sierra Nevada mountain range. Along with these two actions, a dialogue was initiated with researchers, other government agencies, and user groups to discuss management of the Sierra Nevada aquatic ecosystems. This continuing project is closing the gap in baseline data necessary to develop biologically sound long term aquatic biodiversity management plans specific to hydrologic basins of the Sierra Nevada. CDFW anticipates that development and implementation of these plans will help stabilize and reverse negative effects of non-native fish introductions on native frog populations while maintaining viable recreational angling as a historic use pattern in a manner consistent with both the mission of CDFW guidelines set forth in the federal Endangered Species Act. There are now 22 lakes and associated waters that are fishless and being managed for native frogs.
Aquatic Biodiversity Management Plans and Restoration Activities
Fisheries management plans are needed for all high Sierra waters to assure that trout fisheries are managed in a manner compatible with other native aquatic and riparian resources. Fisheries management plans must comply with individual future species recovery plans or conservation strategies which may impart additional fisheries management constraints. CDFW plans should attempt to optimize recreational benefits while maintaining natural biodiversity using a basin-by-basin approach.
Twenty-two Management Units (MU's) including 105 Planning Watersheds (PWS) have been identified for management by CDFW's Bishop Field Office. Most units are defined by watershed boundaries; however, several adjacent smaller basins may be combined to form a management planning unit. Management plans for these areas should be site specific, based on current assessments of fish and amphibian populations, angler use, and the status of key native biota and habitats.
In 1995 the CDFW initiated the High Mountain Lakes project and began site specific resource assessments throughout the Sierra Nevada. Each waterbody within a PWS was identified using a statewide GIS coverage and given a unique identifying number. Each site was visited and surveyed for habitat characteristics (littoral zone substrate, littoral zone depth and shoreline terrestrial substrate), tributary characteristics (width, depth, spawning habitat and fish barriers) fisheries information (fish presence/absence, species, sex ratio and spawning readiness) and target amphibians (species, life stage and disease) according to specific protocols. Site photographs were taken and detailed sketches were made. Photos of fish and amphibians (if any) were also taken. Sterilization protocols were incorporated to ensure that survey crews were not vectors for the distribution of any diseases.
In 1999, after completion of baseline surveys, the CDFW finalized and began implementing an Aquatic Biodiversity Management Plan (ABMP) for the Big Pine Creek Wilderness Basin of the Sierra Nevada. That management plan addressed both CDFW's public trust responsibilities for management and protection of native aquatic species and CDFW's historic and future management of fishery resources in the basin. Currently the Inland Desert Region has completed eight (of 22) ABMP's and three more are in draft form.
The following objectives are being used to develop all ABMP's in the Inland Deserts Region.
- Objective 1: Manage high mountain lakes and streams in a manner which maintains or restores native biodiversity and habitat quality, supports viable populations of native species, and provides for recreational opportunities considering historical and future use patterns. In some areas, most or all of the waters may be managed as natural reserves with little or no angling available. Likewise, in areas of high recreational demand, most or all of the lakes may be managed for recreational angling.
- Objective 2: Trout stocking allotment changes should be based on site-specific data collected within the last 7 years.
- Objective 3: For each lake, the species, frequency, and number of trout stocked should be guided by the following provisions:
- A) Lakes with existing populations of R. muscosa or R. sierrae should generally not be stocked with fish. Where a R. muscosa or R. sierrae population exists within two kilometers of an established high mountain lake fishery, an assessment of fishing use and the feasibility of trout removal should be made to determine if the water could be converted to a fishless condition to benefit R. muscosa or R. sierrae.
- B) Stocking waters in areas with other amphibian Species of Special Concern, such as the Yosemite toad, Bufo canorus, will be reviewed to assure that the native biodiversity objective is met within the management planning unit.
- C) Golden trout, Oncorhynchus mykiss aguabonita, are native to the South Fork Kern River and are sometimes given priority over other trout species and stocked into waters following existing Fish and Game Commission policy. Other species of trout may be stocked to meet other fishery management objectives and for experimental fisheries management programs. However, the stocking of brook trout should generally be avoided because they are a lake-spawning species with a greater tendency to become overabundant and produce stunted populations at the expense of native amphibians and other trout species. Brook trout should not be stocked where their range may be extended.
- D) After achieving the aquatic native biodiversity objectives above, high mountain lakes could be managed to optimize angling opportunity within a given basin. For example, some lakes might be managed for trophy-sized fish, some for fast-action on smaller-sized fish, and others for angling species diversity.
- E) Trout should not be stocked into waters with existing self-sustaining trout populations unless needed to meet goals for improving angling diversity, trophy or fast-action fishing, or research. Experimental planting of trout to control undesirable fish populations is allowed under this provision.
- F) In addition to the application of chemical piscicides in lakes, new and innovative non-chemical means to control undesirable fish populations should be encouraged to avoid impacts on non-target species, including, but not limited to, the use of stocked sterile piscivorous trout, strains or species of fish not previously stocked, or physical means of removal.
Status of management plan
Currently the Inland Deserts Region has completed baseline surveys on 95% of the identified waterbodies (well over 3000) within all 22 MU's. Data has been rendered into GIS coverage files and entered into a database. Presence of fish and amphibian species can be displayed on basin wide maps and examined on a large landscape scale. Decisions regarding stocking, native species restoration and fish removal can be made at the PWS level in accordance with the management goals and objectives, while considering historical and future use objectives. Monitoring survey schedules have been created and implemented.
The Inland Deserts Region has identified approximately 40 Rana sierrae populations within the 22 MU's. Most are very small populations relegated to marginally sufficient habitat. Eleven restoration projects have been implemented and seven have been completed. These seven restoration projects had small, at-risk, pre-existing populations of Rana sierrae in the area and the restoration effort involved fish removal from breeding and overwinter habitat. It should be noted that fish removal is necessary since Rana sierrae and introduced trout require the same lake habitat type (sufficient depth). Fish removal and habitat expansion has resulted in large increases of native a quatic invertebrate and amphibian populations. In all, a total of nineteen lakes or ponds have been or are in the process of being converted to fishless.