Preliminary juvenile Lost River and shortnose sucker investigations in Clear Lake, California: 2011 Pilot study summary (original) (raw)
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The Nature Conservancy undertook restoration of the Williamson River Delta Preserve with a primary goal "to restore and maintain the diversity of habitats that are essential to the endangered [Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris)] while, at the same time, minimizing disturbance and adverse impacts" (David Evans and Associates, 2005). The Western Fisheries Research Center of the U.S. Geological Survey was asked by the Bureau of Reclamation to assist The Nature Conservancy in assessing the use of the restoration by larval and juvenile suckers. We identified five obtainable objectives to gauge the habitat suitability for young-of-year suckers in the permanently flooded portions of the two most recently restored sections (Goose Bay and Tulana) of the Williamson River Delta Preserve (hereafter referred to as the Preserve) and its effects on the distribution and health of larval and juvenile suckers. Several of these objectives were met through collaborations with The Nature Conservancy, Oregon State University, Oregon Water Science Center, and Leetown Science Center. Our findings were in concurrence with those of The Nature Conservancy, who found that the Preserve supported young-of-year suckers at least as well as adjacent lake habitats (Erdman and others, 2011) despite the prevalence of non-native and piscivorous species in the system. The Preserve was recolonized by all fishes in the regional species pool, both native and non-native, between the time each portion of the Preserve (Goose Bay and Tulana) was inundated in autumn and the following spring. A large number of fish capable of preying on endangered larval suckers and a few fish that could prey on juvenile suckers were captured in the Preserve, but these species were no more abundant in the Preserve than in adjacent lakes. Larvae and age-0, age-1, and age-2 juvenile Lost River and shortnose suckers were captured in the Preserve, Upper Klamath Lake, and Agency Lake, indicating that these species reared in restored and unaltered lake habitats. We captured too few larval suckers to examine patterns in spatial or temporal distribution. Once endangered suckers transitioned into juveniles, as defined by morphological development, they continued to disperse from shallow to deep water throughout the Preserve and into adjacent lakes. Age-1 and age-2 suckers captured throughout the Preserve and in adjacent lake habitats, especially in spring, show continued use of restored habitat by these species. 2 Quantitative examination of habitat use by age-0 juvenile suckers that accounted for imperfect detection indicated the portion of habitat used increased throughout July and August each year until the entire study area was used by one or more age-0 juvenile suckers by the end of August. Our rigorous evaluation showed both restored Preserve and unaltered lake habitats were equally used by age-0 juvenile suckers. Although all sampled habitats were used, multi-state occupancy models indicated that more age-0 suckers occupied shallow rather than deep habitats within the range of depths we sampled (0.5–4.3 m). We were unable to compare health and condition of juvenile suckers among habitats, due to their movement among habitats. However, documentation of length-weight relationships, afflictions and deformities, and histology indicated juvenile suckers captured in all habitats maintained a similar level of health among the 3 years of our study.
Transactions of the American Fisheries Society, 2003
We examined the process of larval out-migration of endangered Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris from spawning grounds in the Williamson and Sprague rivers to rearing grounds in Upper Klamath Lake. Most downstream movement occurred at night, when larvae drifted in surface currents at the center of the channel. During daylight, larvae were absent from the drift and abundant near the periphery of the wetted channel, in areas that lacked current. The ages, sizes, and developmental stages of larvae from spawning grounds and the river mouth were similar, indicating that larval suckers transit from spawning grounds to the lake as soon as 1 d after the beginning of the larval period and that inriver rearing is rare. The percent of larvae with empty guts declined from upriver towards the river mouth, suggesting that first feeding is an important driver of the out-migration process. Sucker larvae greater than 13.99 mm standard length were rare in the rivers but abundant in the lake, suggesting out-migration to Upper Klamath Lake is advantageous. Warmer temperatures and greater food availability may be important attributes of lake nursery grounds that are not found in the river. Most larvae entered the system on the falling river hydrograph, a strategy that does not promote floodplain access. Also, larvae of related species do not use floodplains. Therefore, suggestions that channelization and dredging of the lower Williamson River and severance of river-floodplain connectivity by levee construction have negatively affected larval suckers by slowing the out-migration process or eliminating preferred habitats were not supported.
Environmental Biology of Fishes, 2004
We examined near-shore habitat use by larval shortnose and Lost River suckers in the lower Williamson River and Upper Klamath Lake of south-central Oregon. Emergent macrophytes (Scirpus, Sparganium and Polygonum) supported significantly more, larger, and better-fed larvae than submergent macrophytes, woody vegetation, or open water. Abundance, size, and gut fullness were similar for sucker larvae collected from different emergent macropytes. During the larval period, there was no evidence of density dependant effects or habitat shifts. Ranked catch per unit effort data indicated potential predators also were more likely to use emergent macrophytes, but ordination indicated larvae and potential predators were differentially distributed along a vegetation structure-water depth gradient with larvae in shallow vegetated areas. Between-habitat differences appeared to be due to larval sucker selection for, or better survival in, emergent macrophytes, rather than differential access or exclusion from other habitats. The importance of emergent macrophytes appears to be related to increased foraging success and reduced predation. Because larvae in emergent macrophytes have a size and gut fullness advantage, the amount of emergent habitat could affect early survival. However, interannual differences in recruitment to the adult population may or may not be dependent on larval dynamics. Our results suggest larval sucker access to emergent macrophytes may be necessary, but perhaps not sufficient, for promoting good year class formation.
Effects of Lake Surface Elevation on Shoreline-Spawning Lost River Suckers
We analyzed remote detection data from PIT-tagged Lost River Suckers Deltistes luxatus at four shoreline spawning areas in Upper Klamath Lake, Oregon, to determine whether spawning of this endangered species was affected by low water levels. Our investigation was motivated by the observation that the surface elevation of the lake during the 2010 spawning season was the lowest in 38 years. Irrigation withdrawals in 2009 that were not replenished by subsequent winter–spring inflows caused a reduction in available shoreline spawning habitat in 2010. We compared metrics of skipped spawning, movement among spawning areas, and spawning duration across 8 years (2006–2013) that had contrasting spring water levels. Some aspects of sucker spawning were similar in all years, including few individuals straying from the shoreline areas to spawning locations in lake tributaries and consistent effects of increasing water temperatures on the accumulation of fish at the spawning areas. During the extreme low water year of 2010, 14% fewer female and 8% fewer male suckers joined the shoreline spawning aggregation than in the other years. Both males and females visited fewer spawning areas within Upper Klamath Lake in 2010 than in other years, and the median duration at spawning areas in 2010 was at least 36% shorter for females and 20% shorter for males relative to other years. Given the imperiled status of the species and the declining abundance of the population in Upper Klamath Lake, any reduction in spawning success and egg production could negatively impact recovery efforts. Our results indicate that lake surface elevations above 1,262.3–1,262.5 m would be unlikely to limit the number of spawning fish and overall egg production.
Transactions of the American Fisheries Society, 2009
Radiotelemetry was used to investigate the summer distribution and diel habitat associations of endangered adult Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in northern Upper Klamath Lake, Oregon. From 2002 to 2004, Lost River and shortnose suckers were tracked by boat, and water depth and water quality were measured at each fish location. A series of water quality monitors were deployed in northern Upper Klamath Lake to provide temporal information on ambient temperature, pH, and dissolved oxygen, and water samples were collected to assess chlorophyll a concentration. Suckers moved into northern Upper Klamath Lake during June and began to leave in late September each year. Kernel density estimates revealed differences in the distribution in the northern portion of Upper Klamath Lake in 2002 and 2004. In 2003, however, both Lost River and shortnose suckers were commonly located within and offshore from Pelican Bay, a shallow (1.0-2.0 m), groundwater-influenced area of Upper Klamath Lake. This was especially obvious beginning in late July of 2003, concurrent with reduced dissolved oxygen levels (,4.0 mg/L) in the northern portion of Upper Klamath Lake that resulted from a dieoff of the cyanobacterium Aphanizomenon flos-aquae. Both Lost River and shortnose suckers were generally associated with water depths greater than the mean depth (2.8 m) of northern Upper Klamath Lake. Evidence ratios did not suggest diel differences in depth, temperature, dissolved oxygen, or pH at sucker locations. Both Lost River and shortnose suckers generally occupied depths greater than 2.0 m, except when suckers sought refuge in Pelican Bay during periods of poor water quality. Despite the potential for increased avian predation, suckers appeared to benefit from moving into Pelican Bay rather than staying in areas where dissolved oxygen was low. Pelican Bay appears to be an important refugium and thus may be important for sucker conservation.
Abstract.—Population declines of the federally endangered Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris have been linked to several factors, including the loss of larval nursery habitat associated with lake fringe and riparian wetlands. Restoration of deltaic wetlands in the Williamson River delta, Oregon, is regarded as one strategy that may increase larval nursery habitat and survival. This study examined larval sucker presence, growth, development, and feeding in pilot restoration wetlands at the Williamson River delta to determine whether wetland restoration provides habitat that is conducive to larval rearing. We compared results from the restoration wetlands to those in riparian and lacustrine wetland reference sites during 2003 and 2004. The seasonal timing of larval Lost River and shortnose suckers captured in the restoration wetlands was similar to that in reference sites during the April– July study period. The frequency of occurrence in the restoration wetlands was comparable to that in reference sites; larvae were collected in 90–100% of transects during periods of peak abundance. These data are an indication that restored wetlands provide critical habitat for larval suckers. Larval sucker length, developmental phase, and gut fullness in the restoration wetlands indicated that larvae were feeding, growing, and hence, rearing, in those areas. Water temperatures in the restoration wetlands were 3–48C higher than those in reference sites, especially early in the season, which may have increased the restoration sites’ suitability for larval rearing compared with reference sites. Our results indicate that initial wetland restoration efforts at the Williamson River delta have successfully created suitable rearing habitat for larval Lost River and shortnose suckers and suggest that further large-scale wetland restoration in the delta will increase larval rearing opportunities and contribute to the recovery of these two endangered species. Freshwater fish are becoming threatened or extinct at an alarming rate, both regionally and worldwide (Moyle and Leidy 1992; Richter et al. 1997; Ricciardi and Rasmussen 1999). A common cause of these declines is the loss of critical habitat for one or more life stages (Poff and Allan 1997; Fuiman and Werner 2002). In some cases, there may be so little habitat remaining that habitat restoration becomes essential to the recovery of the at-risk species (Allan and Flecker 1993; Cook et al. 2005). However, habitat restoration is often costly and potential benefits are, at times, uncertain. To determine how well the restored habitat functions, it is practical to examine the abundance and condition of the target species occupying the restored habitat. In this study, we used field observations to quantify larval responses of two endangered catostomids, the Lost River sucker Deltistes luxatus and shor sucker Chasmistes brevirostris, to wetland restor Both species are large, long-lived, highly f lacustrine suckers that are endemic to the Klamath River basin of Oregon and California ( pettone and Vinyard 1991; Moyle 2002). Histori these species were abundant throughout their (Cope 1879; Gilbert 1898; Coots 1965), but ov past century they have declined to such a degree warrant listing as endangered species (Andreasen Bienz and Ziller 1987; USFWS 1988). Se factors—including overfishing, degraded water q water diversions, competition with and predati exotic species, and habitat loss and modification been linked to these declines (USFWS 1988, 2001). The largest remaining adult populations of