B08_Attach_(3)_Appendix_B_-_LakeMeadLMP_BO-2018.pdf

United States Department of the Interior Fish and Wildlife Service

Arizona Ecological Services Office 9828 North 31st Avenue, C3

Phoenix, Arizona 85051 Telephone: (602) 242-0210 Fax: (602) 242-2513

In Reply Refer to:

AESO/SE02-21-01F-0263-R

1-5-05-F-417-R

December 07, 2018

Memorandum

To: Superintendent, Lake Mead National Recreation Area, National Park Service, Boulder City, Nevada

From: Field Supervisor, Arizona Ecological Service Field Office

Subject: Reinitiation of Lake Mead National Recreation Area Lake Management Plan for

Low Water General Management Plan Amendment

Thank you for your request for consultation with the U.S. Fish and Wildlife Service (Service) pursuant to section 7 of the Endangered Species Act of 1973 (16 U.S.C. 1531- 1544), as amended (Act). Your request for reinitiation of consultation dated August 22, 2018, was received by us on September 4, 2018; with all needed information being received on October 30, 2018. At issue are impacts that may result from the National Park Service’s (NPS) proposed amendment to the Lake Mead National Recreation Area Lake Management Plan (LMP) for Low Water General Management in Mohave County, Arizona and Clark County, Nevada. In 2002, the Service issued a Biological Opinion (BO) for the LMP, and further issued an amended BO in 2005 when NPS requested reinititation because the proposed actions had changed. In these former BO, the species of concern were the endangered southwestern willow flycatcher (Empidonax traillii extimus), bonytail chub (Gila elegans), razorback sucker (Xyrauchen texanus) and threatened desert tortoise (Gopherus agassizii); for which there were “may affect, likely to adversely affect” determinations made. Additionally, the former requests determination that the action of the LMP may affect, but was not likely to adversely affect the Yuma clapper rail (Rallus obsoletus yumanensis) and the bald eagle (Haliaeetus leucocephalus, at the time listed as endangered). With the exception of the bald eagle, which is no longer listed as endangered and therefore does not require section 7 consultation under the ESA; the impact analyses, determinations, and coverage of the other listed species are still valid and remain in place under the 2002 and 2005 BOs. In the current 2018 amended LMP and request, NPS is requesting reinitation for the razorback sucker and associated critical habitat only, due to the specific actions, affected habitats, and the amendment to the plan only occurring in Lake Mead. Consequently, NPS has made “no effect determinations for bonytail chub (Gila elegans) and yellow-billed cuckoo (Coccyzus americanus). Federal agencies are not required to consult with the Service if a no effect determination has been made, and therefore we will not address these species further in this BO. We offer this supplemental BO to address additional impacts to razorback suckers for adjustments to activities under the Low Water General Management Plan amendment. This amended BO does not preclude or negate any minimization or conservation actions or the analyses of potential take of listed species associated with the previous consultations; but instead supplements these previous consultations.

This BO is based on information provided in the admin record for the 2002 and 2005 BOs, including those BOs, the August 22, 2018 amended Low Water General Management Plan Biological Assessment (BA), and meetings and correspondence between staff. Literature cited in the BO is not a complete bibliography of all literature available on the species of concern or other subjects considered in this BO. A complete administrative record of the 2002, 2005, and this consultation are on file in this office.

Consultation History

October 7, 2002 The Service issues a BO for NPS’s Lake Mead LMP.

May 27, 2005 The Service issues a BO for NPS’s Amended LMP.

September 4, 2018 The Service receives request to reinitiate consultation for the amended

LMP for Low Water General Management Plan Amendment.

November 1, 2018 Draft BO is provided to NPS for review.

November 12, 2018 NPS Draft BO comments received.

BIOLOGICAL OPINION

DESCRIPTION OF THE PROPOSED ACTION

The Lake Mead National Recreation Area (NRA) contains 1,501,216 acres of land in Nevada and Arizona, of which 1,484,159 acres are in Federal ownership administered by the NPS. The LMP encompasses two constructed reservoirs on the Colorado River in Arizona and Nevada including the 157,900 surface acres and over 700 miles of shoreline of Lake Mead and 28,260 surface acres and 150 miles of shoreline of Lake Mohave.

The project area also includes new extensions of existing roads within the NRA in order to maintain access to the shoreline of the lake. The LMP supplemented the General Management Plan finalized in 1986. To date, the LMP has guided recreational use, facilities development and operation, monitoring needs and other management actions as described in the Environmental Impact Statement (EIS) (NPS 2002a). The full text of the proposed action is contained in the EIS and is incorporated into this BO by reference. Some minor changes to the proposed action were documented in the July 31, 2002, NPS memorandum to the FWS (NPS 2002b). An additional amendment and BO was issued in 2005, which outlined changes to the action, and BO coverage are still valid.

The current amendment to include actions under the Low Water General Management Plan adds, modifies, and supplements actions in the 2002 and 2005 BOs. Although elements of the 2005 plan will remain valid, the 2005 plan did not foresee the current and predicted drought condition and did not fully consider the effects to greater fluctuations in the lake’s water level on the operations of launch ramps and marinas. Should the lake level drop below 1,050 feet in elevation, not all actions in the 2005 BO will be applicable regarding actions related to launch ramps and marinas and public access to the lake would be reduced, in that actions will happen at lower lake elevations than what was previously analyzed. The current action proposes activities that would occur at lower lake elevations should lake elevations drop below 1,050 feet and are planned for lake elevations as low as 950 feet. Bureau of Reclamation (Reclamation) water level projections indicate there is a 25% chance the lake level will decline below 1,050 by the year 2022 and a 50% chance by 2028, should current water management strategies remain as they are currently. Amendments to this plan and modifications to infrastructure are not anticipated to increase recreational use within the action area, but rather to facilitate the existing use level should lake elevation levels drop to such a point that existing facilities are not functional. Modifications to site specific locations are the focus of the BO and are outlined below.

The proposed amendment would change the configurations and locations of marinas and/or boat launch ramps at: Hemenway Harbor, Callville Bay, Temple Bar, Echo Bay, and South Cove. Additional maintenance would occur at Government Wash, Kingman Wash, and Stewarts Point to facilitate small personal watercraft such as paddleboats, camping, swimming, and picnicking. Maintenance of shoreline access below the current lake elevation at underdeveloped launch areas around the lake may be needed. Methods of maintenance in these areas would remain the same as outlined in the previous BOs, but would occur at a lower lake elevations (between 1,050’ and 950’). The elevations cited in this action are approximate, but it is assumed that approximately 5 feet of water depth is needed for boat launching and approximately 10 feet is needed for marina operations. These management actions are integral to the effective and safe operation of lake access infrastructure and facilities.

The size of floating marinas that require relocation will not be substantially changed, however, anchoring systems will be relocated. To accommodate these changes, walkways and courtesy docks will be extended, marina configurations will be adjusted, and breakwater structures will be modified. Where site conditions are appropriate, extension of launch ramps will occur by paving to water line, or temporary structure placement such as concert planks, rock/gravel, piping, or temporary coffer dams.

Existing parking and traffic circulation facilities will also be modified in areas below the high waterline, when those areas are out of the water and above the current lake elevation. This includes the current methods of grading, paving, or addition of stabilizing base materials.

Additional actions such as grading and paving walkways, walkway entrances, and vehicle parking pads will also be maintained near modified boat launch and marina areas.

Utilities infrastructure necessary for water, sewer, power, telephone, cable, and fuel service will be extended below the high waterline as lake levels recede to maintain service at each marina. All current methods of maintenance for these facilities will be constructed as is currently outlined in the 2002 and 2005 BOs, but they would extent to lower lake elevations.

Only portable shoreline amenities will be provided as needed, including; temporary restrooms, shade shelters, picnic facilities, fish cleaning stations, and informational kiosks. No permanent facilities will be constructed below the designated high water elevation because those facilities could be damaged if, and when, reservoir levels raise.

Site Specific Actions

Hemenway Harbor

The marinas in Hemenway Harbor are collectively one of the countries largest inland marinas with 1,400 boat slips, and includes; Las Vegas Boat Harbor, Lake Mead Marina, and Lake Mead Cruises. In response to the dropping lake levels, the boat launch ramp and marina will continue to be pushed out farther into the lake, to a lake elevation of approximately 1,000 feet.

Additionally, for elevations between 1,000 and 950 feet, the boat launch ramp and marina will be adjusted closer to the Hemenway Wall. Existing roads and parking lots will either be extended or relocated closer to the in-water structures. The number of parking places and boat slips will not increase beyond existing numbers.

Callville Bay

Callville Bay has two boat launch ramps, one of which is not functional since lake elevation level has dropped below 1,087 feet. At their current locations, these boat launch ramps can be extended only down to an elevation of 1,050 feet. There are several operating concessionaires at this location, including campground, restaurant, store, and trailer village. These facilities are anticipated to maintain function until the lake level drops to approximately 1,070 feet.

Should lake levels drop below this water elevation these facilities may be relocated to the nearby Swallow Bay. A new road to Swallow bay and a parking lot will be constructed below the high water line, down to a lake elevation of 950 feet should those environmental conditions arise. The number of parking places and boast slips will not increase from beyond existing numbers.

Echo Bay

Echo Bay is the northernmost public access point to the lake. The floating marina and original boat launch ramp were closed in 2013 and modifications were made as the lake elevation dropped below 1,100 feet. During this time a new public launch ramp and accompanying access road and parking lots were constructed. The current boat launch ramp will be extended down to the lake until a water elevation of approximately 1,050 feet. Below 1,050 feet the ramp would be relocated and moved further downwash to maintain functionality to an elevation of 1,000 feet. Should the lake elevation recede below an elevation of 1,000 feet, this facility will be closed. The number of parking places and boat slips will not increase from beyond existing numbers.

Temple Bar

The Temple Bar facility includes concession operated land facilities (e.g. motel, campground, restaurant, store), one boat launch ramp, and a floating marina. The boat ramp is located in an inlet at the southwest end of the cove and extends down to the water level of 1,080 feet. The existing ramp can extend approximately another 400 feet before it loses its function. The floating marina continues to be pushed out to follow lake elevation trends and will remain functional until lake elevations drop to 1,030 feet. Should lake elevations drop below 1,050 feet, the boat launch ramp will be moved to a new location within this cove and the Marina will continue to be relocated farther out into the lake. A new road will be built to provide access to the ramp and marina. The number of parking places and boat slips will not increase from beyond existing numbers.

South Cove

Extension of the existing South Cove boat launch will occur down to a lake elevation of 1,050 feet; after which point this area will be closed. There are no marina or utility facilities at this location. The number of parking places will not increase from beyond existing numbers.

Conservation Measures

The following conservation measures were proposed for this amended LMP plan. Additional Conservation Measures, Reasonable and Prudent Measures, and Terms and Conditions are included in the 2002 and 2005 BOs, and those actions are still valid and included in this BO by reference. The following conservation measures include, but are not limited to, the below;

1. Surveys of areas within Lake Mead known to have razorbacks, including Echo Bay, will continue.

2. Boat use during the spawning period of coves identified as native fish spawning areas will be monitored. If boat use increases dramatically or if the Native Fish Work Group recommends action, closures of the coves to boat use during the spawning period will be implemented.

3. Information about native fish in the lakes will be provided at marinas and with boat rentals. Information will encourage boaters not to use the spawning areas during the spawning season.

4. All marinas will operate under the Lake Mead National Recreation Area Best Management Practices, Watercraft and Marina Operations, and Dry Boat Storage and Boat Repair Services” or subsequent revised versions of the existing document. This document provides for management that reduces the risk of toxic spills into the lakes by fueling and other marina operations.

Additional conservation measures will also be implemented, and include;

1. Pre-activity surveys will be conducted for evidence of razorback spawning in areas where spawning habitat could potentially be disturbed due to construction or marina relocation activities.

2. In areas around known spawning beds, construction activities will not occur during the spawning season.

3. Should new spawning locations be discovered, NPS will contact the Arizona Ecological Services Office (AESO) prior to in-water construction at those locations.

4. An annual report of construction and monitoring activities will be provided to AESO so that baseline information and species status information can be maintained.

Description of the Action Area

The Lake Mead National Recreation Area (NRA) contains a total of 1,501,216 acres of land, the majority of which is under Federal ownership administered by the NPS. The LMP includes Lake Mead and Lake Mohave, and this amended, supplemental BO, focuses on activities that will occur around and within Lake Mead. The project area also includes new extensions of existing roads within the NRA in order to maintain access to the shoreline of the lake. The LMP guides recreational use, facilities development and operation, monitoring needs and other management actions as described in the Environmental Impact Statement (EIS) (NPS 2002a) the 2005 amended plan.

This current amended plan pertains to the same action area within Lakes Mead, but includes actions that will occur below the high water level, down to a lake elevation of 950 feet. Site specific actions have been identifies in the Lake Mead area and include; Hemenway Harbor, Callville Bay, Temple Bar, Echo Bay, South Cove, Government Wash, Kingman Wash, and Stewarts Point.

STATUS OF THE SPECIES AND CRITICAL HABITAT

The information in this section summarizes the rangewide status of each species that is considered in this BO. Further information on the status of these species can be found in the administrative record for this project, documents on our web page (Arizona Ecological Services Office Documents by Species), and in other references cited in each summary below. An additional summarized review of the current status of the razorback sucker can be found in the Species Status Assessment report for the Razorback Sucker (Xyrauchen texanus) (Service, 2018).

Razorback sucker

Description

The razorback sucker is the only representative of the genus Xyrauchen and was described from specimens taken from the “Colorado and New Rivers” (Abbott 1861). This native sucker is distinguished from all others by the sharp-edged, bony keel that rises abruptly behind the head.

The body is robust with a short and deep caudal peduncle (Bestgen 1990). The razorback sucker may reach lengths of 3.3 feet (1.0 m) and weigh 11 to 13 pounds (5.0 to 5.9 kilograms [km]) (Minckley 1973). Adult fish in Lake Mohave reached about half this maximum size and weight (Minckley 1991). Razorback suckers are long-lived, reaching the age of at least 40 years (Minckley et al. 1991).

The razorback sucker is somewhat sedentary; however, considerable movement over a year has been noted in several studies (Service 1998, 2018). Spawning migrations have been observed or inferred in several locales (Jordan 1891, Minckley 1973, Osmundson and Kaeding 1989, Bestgen 1990, Tyus and Karp 1990). During the spring spawning season, razorback suckers may travel https://www.fws.gov/southwest/es/arizona/Docs_Species.htm https://www.fws.gov/southwest/es/arizona/Docs_Species.htm long distances in both lacustrine and riverine environments, and exhibit some fidelity to specific spawning areas (Service 1998, 2018). Since 1997, significant new information on recruitment of the wild razorback sucker population in Lake Mead has been developed (Albrecht et al. 2008, Kegerries et al 2017) that indicate some degree of reproduction is occurring at three locations in Lake Mead, and another spawning group was documented in 2010 at the Colorado River inflow area of the lake (Albrecht et al. 2010, Kegerries and Albrecht 2013).

Listing and critical habitat

The razorback sucker was first proposed for listing under the ESA on April 24, 1978 (43 FR 17375), as a threatened species. The proposed rule was withdrawn on May 27, 1980 (45 FR 35410), due to changes to the listing process included in the 1978 amendments to the ESA. In March 1989, the Service was petitioned by a consortium of environmental groups to list the razorback sucker as an endangered species. The proposed rule to list the species as endangered was published on May 22, 1990 (55 FR 21154), and the final rule published on October 23, 1991, (56 FR 54957), with an effective date of November 22, 1991. The Razorback Sucker Recovery Plan was released in 1998 (Service 1998). Recovery Goals were approved in 2002 (Service 2002). Critical habitat was designated in 15 river reaches in the historical range of the razorback sucker on March 21, 1994 (59 FR 13374). Critical habitat included portions of the Colorado, Duchesne, Green, Gunnison, San Juan, White, and Yampa rivers in the Upper Colorado River Basin, and the Colorado, Gila, Salt, and Verde rivers in the Lower Colorado River Basin. The primary constituent elements are water (a quantity of sufficient quality that is delivered to a specific location in accordance with a hydrologic regime that is required for the particular life stage), physical habitat (areas of the Colorado River system that are inhabited or potentially habitable by the sucker for use in spawning, nursery, feeding, and rearing, or corridors between these areas), and biological environment (food supply, predation, and competition) that influence all life stages. In addition, areas and habitats considered essential for reproduction and recruitment were specifically included.

Reasons for listing

The range and abundance of the razorback sucker has been severely impacted by water manipulations, habitat degradation, and invasion of non-native aquatic species. Construction of dams, reservoirs, and diversions destroyed, altered, and fragmented habitats needed by razorback suckers. Channel modifications have reduced habitat diversity, and caused degradation of riparian and altered upland area stream morphology and hydrology. Finally, invasion of these degraded habitats by a host of non-native, predacious and competitive species has created a hostile environment for razorback sucker larvae and juveniles. Although razorback suckers spawn each year and produce large numbers of larvae, the larvae are preyed on by non-native fish species (Minckley et al. 1991) and recruitment to reproductive age is not occurring in most populations (Service 2002).

Habitat

Adult razorback suckers use most of the available riverine habitats, although there may be an avoidance of whitewater type habitats. Main channel habitats used tend to be of low velocity such as pools, eddies, nearshore runs, and channels associated with sand or gravel bars (Bestgen 1990). Adjacent to the main channel, backwaters, oxbows, sloughs, and flooded bottomlands are also used. From studies conducted in the upper Colorado River basin, habitat selection by adult razorback suckers changes seasonally. They move into pools and slow eddies from November through April, runs and pools from July through October, runs and backwaters during May, and backwaters, eddies, and flooded gravel pits during June. In early spring, adults move into flooded bottomlands. They use relatively shallow water (ca. three feet [0.9 m]) during spring and deeper water (five to six feet [1.5-1.8 m]) during winter (Service 2002). Razorback suckers also use reservoir habitat, where the adults may survive for many years. In reservoirs, they use all available habitat types, but prefer backwaters and main impoundment areas (Service 1998).

Much of the information on spawning behavior and habitat comes from fishes inhabiting reservoirs where observations can readily be made. Habitat needs of larval and juvenile razorback suckers are reasonably well known. In reservoirs, larvae are found in shallow backwater coves or inlets (Service 1998). In riverine habitats, captures have occurred in backwaters, creek mouths, and wetlands. These environments provide quiet, warm water where there is a potential for increased food availability. During higher flows, flooded bottomland and tributary mouths may provide these types of habitats.

Rangewide distribution and abundance

The historical range of the razorback sucker included the main stem Colorado River and its tributaries from northern Mexico through Arizona and Utah into Wyoming, Colorado, and New Mexico. Distribution and abundance of the razorback sucker declined during the last century throughout the known range, and the species now exists only in 8 small populations, the majority of which are reliant on stocking to maintain presence. The razorback sucker inhabiting the large reservoirs of the Lower Colorado River have maintained populations long after dams changed the river to a string of impoundments. The populations existed almost solely by virtue of the species’ longevity, not by documented recruitment to reproductive age into existing populations.

Razorback sucker populations rely on the Lower Colorado River Multi-Species Conservation Program’s (LCR MSCP) augmentation, which is expected to release 660,000 razorback suckers throughout its historical range over the program’s 50-year period (2005 through 2055).

Past Consultations

The lower Colorado River has been subject to the effects of Federal, State, and private activities for over 120 years. The greatest changes have come in the last 80 years, with the construction of large dams. Impacts of these human activities to the river have had profound effects on the river itself, associated riparian and floodplain areas, and the river’s aquatic fauna. Significant changes to seasonal flow and water quality have resulted from the storage of water behind Hoover, Davis, and Parker dams. Water diversions and return flows, flood control projects that stabilized river banks and prevented natural meandering by the river, agricultural and urban development, recreational activities, along with changes in seasonal flows have impaired the ability of aquatic habitats to support native fish. In addition to physical changes to the river system, introductions of nonnative fish species to the Colorado River Basin were made for commercial and recreational purposes. An assemblage of nonnative fish species now exists along nearly all sections of the Colorado River.

For the most part, early Federal activities along the Colorado River did not undergo section 7 consultations because many were completed prior to the inception of ESA, and fish were not listed at this time. Earlier section 7 consultations focused mainly focused on sport fish enhancement programs. Currently, in the lower Colorado River, the LCR MSCP addresses effects of water management and provides conservation to offset effects of water operations; and is largely responsible for the current existence of razorback suckers in the lower basin. The LCR MSCP funds and maintains the majority of restoration efforts of the razorback sucker in the mainstem of the Colorado River below Lake Mead. Several Statewide consultations have occurred including the Land and Resource Management Program with the Forest Service and the intra-Service consultation on Sport Fish Restoration Funding which evaluated the sport fish stocking program funded by the Service (Service 2011). Smaller site specific consultations addressing channelization, recreational development, recreational sport fishing, and implementing recovery actions have also occurred. All prior consultations have reached non-jeopardy and non-adverse modification conclusions.

Biological opinions on actions potentially affecting the razorback sucker in Arizona may be found at our website www.fws.gov/southwest/es/arizona in the Section 7 Biological Opinion page of the Document Library.

Critical Habitat

Critical habitat for razorback sucker was designated in 1994 which included Lake Mead within the action area. Critical habitat was designated for the four big river fishes (Colorado Pikeminnow (Ptychocheilus Lucius), humpback chub (Gila cypha), bonytail chub (Gila elegans), and razorback sucker concurrently in 1994, and the primary constituent elements (PCEs) were defined for the four species as a group (Service 1994). However, the PCEs vary somewhat for each species on the ground, particularly with regard to physical habitat, because each of the four species has different habitat preferences. The PCEs are:

• Water: Consists of water of sufficient quality (i.e., temperature, dissolved oxygen, lack of contaminants, nutrients, turbidity, etc.) that is delivered in sufficient quantity to a specific location in accordance with a hydrologic regime that is required for the particular life stage for each species.

• Physical Habitat: This includes areas of the Colorado River system that are inhabited by fish or potentially habitable for use in spawning, nursery, feeding, or corridors between these areas. In addition to river channels, these areas include bottomlands, side channels, secondary channels, oxbows, backwaters, and other areas in the 100-year floodplain, which when inundated provide spawning, nursery, feeding, and rearing habitats, or access to these habitats.

• Biological Environment: Food supply, predation, and competition are important elements of the biological environment and are considered components of this constituent element. Food supply is a function of nutrient supply, productivity, and availability to each life stage of the razorback sucker. Predation, although considered a normal component of this environment, is out of balance due to introduced fish species in some areas. This is also true of competition from nonnative fish species.

• The PCEs are all integrally related and must be considered together. For example, the quality and quantity of water affect the food base directly because changes in water chemistry, turbidity, temperature, and flow volume all affect the type and quantity of organisms that can occur in the habitat that are available for food. Likewise, river flows and the river hydrograph have a significant effect on the types of physical habitat available. Changes in flows and sediment loads caused by dams may have affected the quality of nearshore habitats utilized as nursery areas for young razorback suckers.

Increasingly the most significant PCE seems to be the biological environment, and in particular predation and competition, from nonnative species. It is likely that the future conservation of razorback suckers may depend on our ability to control nonnative species, and manipulating the water and physical PCEs of critical habitat to disadvantage nonnatives may play an important role.

ENVIRONMENTAL BASELINE

The environmental baseline includes past and present impacts of all Federal, State, or private actions in the action area, the anticipated impacts of all proposed Federal actions in the action area that have undergone formal or early section 7 consultation, and the impact of State and private actions that are contemporaneous with the consultation process. The environmental baseline defines the current status of the species and its habitat in the action area to provide a platform to assess the effects of the action now under consultation.

Lake Mead was formed by the construction of Hoover Dam in the 1930s. Water stored in Lake Mead is managed by Reclamation in accordance with the Law of the River and flood control requirements. Lake Mead constitutes the sum of Glen Canyon Dam releases (which are under Federal control), inflows from tributaries in the Grand Canyon, and the Virgin/Muddy Rivers.

Lake Mead water levels are managed in conjunction with Lake Powell water levels. Water is released from Lake Mead to meet downstream water orders for Federal, Tribal and State water users and the releases are also planned to generate hydropower under existing contracts. Existing flood control requirements and water and power contracts will continue to affect water releases from Lake Mead, which affects the water surface elevations of the lake.

Status of the Species within the Action Area and Critical Habitat

The razorback sucker population in Lake Mead is the only population in the Lower Colorado River Basin in which there is consistent evidence of natural recruitment (Rogers et al. 2017, Rosen et al. 2012, Service 2018). The population apparently benefited from abundant habitat during the initial filling of the reservoir prior to a rapid decline that began in the 1970s (Albrecht et al. 2010). Based on data obtained from aging of 509 adults and subadults captured during 1996-2016, recruitment occurred in pulses during the 1980’s (Mohn et al. 2017). Recruitment of wild origin razorback sucker was documented annually in Lake Mead between the 1970’s and the 1990’s (Mohn et al. 2015). Reproduction and natural recruitment has been documented annually in turbid inflow areas (i.e., Las Vegas Bay, Echo Bay, and the inflow area of the Virgin and Muddy rivers) since the 1990s (Albrecht et al. 2010). Razorback sucker in the Lake Mead population migrate to and from upstream portions of the Colorado River, as evidenced by larvae captured and telemetry data collected during recent monitoring surveys in the Grand Canyon (Kegerries et al. 2017).

The construction of large mainstem dams has altered water temperatures throughout the Lower Colorado River Basin. This water warms to over 20 °C as it flows downstream into Lake Mead.

Lake Mead water temperatures ranged from 10.4 to 31.2 °C in 2010 in the Temple Basin just downstream of the Colorado River inflow (U.S. Geological Survey 2016). Razorback sucker appear to be opportunistic and successful at spawning in a variety of water temperatures, but water temperature does play an important role in hatching, growth, and survival of larvae (Marsh 1985; Bozek et al. 1990; Bestgen 2008). Some annual variation in reservoir stage is thought to support various life stages, but dramatic increases or decreases in reservoir stage can have deleterious effects, especially during spawning season when eggs may be dried by falling water levels (McCall et al. 2017).

Research related to the abundance and availability of food for razorback sucker in the Lower Colorado River Basin is relatively limited, but nonetheless food supply is thought to be adequate to support growth and survival in all lower basin reservoirs, including Lake Mead. One study on Lake Mohave and nearby backwaters showed abundance of food items and similarities in food availability for larval razorback sucker in both habitats. Since Lake Mohave is the nearest location to Lake Mead that has information pertaining to food for razorback suckers, we assume the status of food availability is similar within the action area and sufficient since the Lake Mead population is recruiting.

Aquatic nonnatives species that prey on or compete with razorback suckers remains one of the largest threats to survival, reproduction and persistence of populations of this species. Despite the dominance of nonnative fish in Lake Mead, razorback sucker continue to reproduce and recruit naturally on an annual basis (Albrecht et al. 2010; Mohn et al. 2015; Kegerries et al.

2015). Although documented predation of juvenile razorback sucker by nonnative fish has occurred (Kegerries et al. 2015), predation and competition do not appear to completely limit recruitment and survival in the Lake Mead razorback sucker population, but it may limit the population size. Cover in the form of turbidity and submerged vegetation in inflow areas seems to be the key feature of Lake Mead that provides necessary conditions for survival and recruitment of larvae and juveniles despite the presence of a robust suite of nonnative fishes (Albrecht et al. 2017). Lake Mead has a sizeable nonnative fish presence, currently dominated by gizzard shad, common carp, striped bass, largemouth bass, smallmouth bass, black crappie and bluegill (Mohn et al. 2017).

The Lake Mead population of razorback suckers has access to Colorado River in Western Grand Canyon, providing additional diverse habitat. When Lake Powell filled in the mid-1960’s, Lake Mead elevations were dramatically decreased, allowing for the establishment of near-shore vegetation. From 2012-2015, water level drawdown associated with drought has allowed terrestrial vegetation to colonize in a downslope direction, which when coupled with annual elevation increases during spring may be providing cover in coves and other habitats that allow for the recruitment occurring there (Mohn et al. 2017). Complex aquatic vegetation structure, coupled with high levels of turbidity near the inflows may cause recruitment success, especially in the Virgin River/Muddy River inflow and Las Vegas Bay (Mohn et al. 2017). Within the Lake Mead inflow areas 59% of individuals (325 adults) captured between 2010 and 2016 were new, wild, untagged fish (Albrecht et al. 2017). Recent research shows movement of telemetered fish from Lake Mead into the lower Grand Canyon and limited captures of adult razorback sucker (Bunch et al. 2012; Albrecht et al. 2014; Rogowski and Wolters 2014; Kegerries et al. 2015). It is unclear whether razorback sucker in the Grand Canyon are an extension of the Lake Mead population, but connectivity does exist between the two.

In Lake Mead, the Colorado River inflow below the Grand Canyon, Virgin/Muddy River inflow area, and Las Vegas Wash provide spawning and recruitment habitat for razorback sucker. Las Vegas Bay and Echo bay are particularly sensitive areas, with spawning and recruitment occurring at these locations. Reproduction is occurring annually and larval razorback sucker are being captured at all three locations (Kegerries et al. 2015; Mohn et al. 2015). Reproduction occurring upstream of Lake Mead in the Colorado River inflow supplies additional larvae to the reservoirs via larval drift (Kegerries et al. 2015; Farrington et al. 2018). In Lake Mead, razorback sucker movement among spawning areas during the spawning season and between years has been documented. More interesting still is movement into and out of Lake Mead by telemetered razorback sucker. From 2010 to 2012, three of five sonic-tagged razorback sucker moved from the lake proper at the mouth of the Colorado River inflow upstream into the mainstem river (Albrecht et al. 2010; Kegerries and Albrecht 2011; Kegerries and Albrecht 2013). Additional sonic-tagged razorback sucker released both in the river and within the lake moved upstream and downstream, with some utilizing both the river and the lake annually.

Trammel netting data from 2010-2017 yielded estimates between 400 and 600 individuals in the Lake Mead and the Colorado River inflow areas (Albrecht et al. 2013; Albrecht et al. 2014;

Mohn et al. 2017). The Lake Mead razorback sucker population, although recruiting, is not as genetically diverse as the Lake Mohave population and shows variability in diversity and relatedness by spawning location and years. Persistent low population numbers are causing concern over genetic diversity and augmentation from Lake Mohave is being considered as a management action.

In summary, Lake Mead is the only location where wild razorback sucker recruitment is occurring despite an abundance of nonnative fish. Spawning grounds are present and commonly used in Lake Mead (Kesner et al. 2014; Mohn et al. 2017; Kesner et al. 2017; McCall et al.

2017). The population remains small, estimated around 500 fish, which is causing concern about its long-term persistence and the potential development of genetic bottlenecks. The LCR MSCP and Native Fish Workgroup members monitors the Lake Mead population regularly.

Critical habitat

Critical habitat for razorback suckers is designated in 15 reaches of the Colorado River System, totaling 2,776 km (1,724 mi). Lake Mead is designated Critical Habitat for razorback suckers.

The current condition of critical habitat within Lake Mead is dissimilar to historical conditions because this area is now a reservoir and has lost its riverine qualities. However many of the PCEs described in Critical Habitat remain to some degree, and maintain some function as habitat for razorback sucker.

The PCEs, as described in the Status of the Species section, are: Water of sufficient quality (i.e., temperature, dissolved oxygen, lack of contaminants, nutrients, turbidity) that is delivered to a specific location in accordance with a hydrologic regime required for the particular life stage for each species; Physical Habitat, areas for use in spawning, nursery, feeding, and movement corridors between these areas; and Biological Environment, food supply, predation, and competition. In summary, the conditions of the PCEs in the Action Area are:

• The physical PCE for spawning and recruitment is present within Lake Mead, where regular spawning occurs in Las Vegas Bay and Echo Bay (Kesner et al. 2014; Mohn et

al. 2017; Kesner et al. 2017; McCall et al. 2017). Growth rates and body condition of adults in LCRB reservoirs are high; indicating the abiotic features formed by reservoirs can be diverse and alone may be beneficial to adults of the species.

• Nursery habitat for juvenile razorback suckers is maintained to some degree in Lake Mead because there is continued documentation of recruitment of juveniles to adult size.

The complex vegetation community coupled with high levels of turbidity near the inflows makes recruitment successful, especially in the Virgin River/Muddy River inflow and Las Vegas Bay, despite having a robust nonnative species composition in the action area (Mohn et al. 2017). Lake Mead contains the only population of naturally recruiting razorback suckers with the presence of this nonnative fish assemblage.

• Although razorback suckers experience restricted movement throughout the Colorado

River due to reservoirs, movement corridors appear to be adequate in Lake Mead based on movements of razorback suckers among different areas within Lake Mead, and between Lake Mead and lower portions of Grand Canyon.

• Food supply is a function of nutrient supply, productivity, and availability to each life stage of the razorback sucker. Research related to the abundance and availability of food for razorback sucker in Lake Mohave is limited, but nonetheless food supply is thought to be adequate to support growth and survival in this reservoir.

• Nonnative fish species that prey on and compete with razorback suckers affect the PCEs of the biological environment aspect of critical habitat. Nonnative species that may harm razorback suckers are present in Lake Mead and managed as sport fish. However, Lake Mead is the only population of razorback suckers that successfully spawn and recruit to adult size and reproductive age. This evidence has lead managers to believe that cover, in the form of vegetation and perhaps turbidity, in the bays and inflows to the lake may be providing sufficient cover to maintain this population at a low level.

• The water quality and quantity PCEs in Lake Mead appears to be abundant and of sufficient temperature to maintain this population of razorback suckers. Pollutants, in the form of petroleum products or urban runoff/effluent, may have effects to habitat quality in shallow areas where recreational use is this or developed facilities exist near know feeding, spawning, or nursery areas. The size of Lake Mead does not provide conditions that would result in high lake-wide levels of these concentrated pollutants. Build-up of endocrine disrupting compounds from human effluents may be present, but it is unknown if these compounds have impacts to razorback sucker reproduction and larval development.

EFFECTS OF THE ACTION

Effects of the action refer to the direct and indirect effects of the proposed action in the species or critical habitat, together with the effects of other activities that are interrelated and interdependent with that action that will be added to the environmental baseline. Interrelated actions are those that are part of a larger action and depend on the larger action for their justification. Interdependent actions are those that have no independent utility apart from the action under consideration. Indirect effects are those that are caused by the proposed action and are later in time, but still are reasonably certain to occur.

Razorback Suckers

Direct and Indirect Effects

The proposed action is to amend the existing 2002 and 2005 Lake Mead National Recreation Area LMP for needed modifications to address low lake elevations; summarized in the Low Water General Management Plan and the conservation measures listed in this opinion. These actions provided a certain level of recreational facilities and recreational use levels including shoreline zoning for Lake Mead and Lake Mohave. The current proposed action contains provisions for existing recreational facilities to continue to operate and for the modification of some existing facilities and construction of new ones at lake elevations in Lake Mead due to drought conditions that will decrease the water elevation of Lake Mead. This plan includes all action listed in the 2002 and 2005 BOs but allows for actions to occur to lake elevations down to 950 feet. It also includes new modifications to specific locations and facilities listed in this BO. The Service maintains that effects to razorback suckers are anticipated to include effects as previously considered under the 2002 and 2005 BOs but these impacts will likely occur at lower lake elevations. These anticipated effects are outlined below.

Recreational opportunity zoning for the NRA in the Urban Natural and Urban Park categories comprises 51% of Lake Mead and 84% of Lake Mohave. These zones contain most of the recreational use allowed for in the proposed action. Effects to threatened and endangered species or designated critical habitat are greatest in these zones. Where recreational activity is high enough to require additional shoreline zoning to designate different activity areas, habitat for species may be significantly disturbed or eliminated.

Within the zones, a component of activities in the LMP involves access facilities (boat ramps, parking lots, marinas) for recreational use within the various shoreline zones. New construction, either at existing or totally new facilities, has effects to shorelines as well as in-lake habitats. Clearing sites for ramps, parking lots, and other buildings increases dust and may introduce sediments into the lake at the construction site. For properly designed sites, these effects do not last long after completion of construction. Placement of launch ramps sufficiently near the lake will allow for use during lower water levels. Placement of such structures converts natural substrates to artificial ones (concrete, metal mesh, or other materials) which could locally reduce habitat for submerged plants and invertebrates when lake levels rise. Fish spawning habitat at these sites is anticipated to be lost. Shoreline vegetation, either riparian (along the shore or in the lower portions of desert washes near the shore) or emergent, may also be eliminated to provide space for the facilities. Roads are also away from the shoreline, but drainage off the roads may cause localized erosion that increases sediment inflow to the lake.

Operation of boat launch and marina facilities also have effects to fish and wildlife habitats in the vicinity of the facility. Noise from operations and nighttime lighting affect local conditions.

Human activity is high and may be disruptive to wildlife. Fish could be affected by noise from boat engines and other mechanical devices and may abandon an area. This is not always the case since fish, especially carp, are abundant around launch areas and marinas. This may be a response to additional cover provided by docks, enhanced food resources from visitors feeding the fish, or other factors. Water quality around boat launch or marina facilities may be an issue for fish health.

Petroleum products and other potential pollutants are introduced to the lakes in a variety of locations including runoff from roads. Day to day operations likely input low levels of these materials to the lakes over a long period of time that allows for dispersal and dilution within the water. At marinas, there is the potential for spills from gas docks and boat maintenance operations that may input significant amounts of pollutants to a small area. These types of incidents may cause injury or death to fish in the vicinity of the facility.

Recreational zoning in the known areas of razorback spawning habitat are in the Urban Park zones of Lake Mead. Both of the Lake Mead razorback spawning groups use habitat in the immediate vicinity of Las Vegas Bay and Echo Bay The level of existing recreational use at these sites has not had any documented effects to the razorback sucker populations.. Intensive monitoring has shown razorback use of the areas consistent over decades. Since spawning, and the highest concentration of use by individual razorbacks is during the lower visitor use periods, the amount of boat noise is less as is the amount of overall human disturbance during these critical periods. During the summer months, the razorbacks are more dispersed along the shorelines away from the marinas and are still in areas of high visitor use in the larger Las Vegas Bay area and Overton Arm.

Continued effects to razorbacks are likely to be in the form of harassment from boat noise, fuel and other pollution events, and reduction in undisturbed shoreline habitats. The razorback habitat near Echo Bay will be closed to boat access during the spawning period, which would reduce the potential for effects to this area.

Potential construction of facilities could cause impacts if it occurs in areas used by spawning razorbacks. During construction activities, there may be increased sedimentation into the lake and greater turbidity in the water. Although turbidity barriers will be used, these effects would be temporary and would cease when construction was completed. Avoidance of construction activities in areas where razorback suckers are actively spawning is anticipated to reduce this impact. Increased launching activities may result in localized reductions in water quality from fuel and other pollutants.

The amount of petroleum products and other pollutants introduced into Lake Mead from operations of marinas and illegal fueling actions outside of approved areas is unknown.

Efforts by NPS to restrict illegal actions through enforcement and education is part of the proposed action, as are guidelines for marina operators providing for best management practices to reduce the potential for toxic materials to enter the lake. Expansion of the number of boats using the lake and its facilities is not anticipated under the amended proposed action but risk of a major spill or the amount of material accidentally or incidentally introduced to the lake remains. The existing degree of risk remains unknown. Use of best management practices will help reduce the risk of contaminants entering the water.

Activities that concentrate predacious fish species near razorback spawning and nursery habitats may affect the potential for future recruitment events. The necessary distance between spawning and nursery habitats and such concentrations of carp and other fish species needed to eliminate any effect to recruitment is unknown.