Larval Lost River and Shortnose Sucker Response to Wetland
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Larval Shortnose and Lost River Sucker Response to Large Scale Wetland Restoration of the North Half of the Williamson River Delta Preserve, Oregon Prepared By: Charles S. Erdman and Heather A. Hendrixson The Nature Conservancy Klamath Basin Field Office 226 Pine Street Klamath Falls, OR 97601 July 2009 Table of Contents PROJECT BACKGROUND............................................................................................ 1 METHODS ........................................................................................................................ 2 SAMPLING DESIGN ..................................................................................................................................... 2 FISH IDENTIFICATION AND CONDITION ..................................................................................................... 5 DATA ANALYSIS .......................................................................................................................................... 6 RESULTS .......................................................................................................................... 6 BI-WEEKLY SAMPLING .............................................................................................................................. 6 LARVAL SUCKER RESPONSE TO A RECENTLY FLOODED WETLAND ......................................................... 14 FIXED POINTS IN TULANA ........................................................................................................................ 15 WATER QUALITY ...................................................................................................................................... 16 DISCUSSION.................................................................................................................. 17 TULANA .................................................................................................................................................... 20 FIXED POINTS IN TULANA ........................................................................................................................ 21 SUMMARY ..................................................................................................................... 21 REFERENCES................................................................................................................ 22 ii Abstract Hydrologic reconnection of deltaic wetlands at the mouth of the Williamson River with portions of Agency Lake and Upper Klamath Lake, Oregon is a restoration strategy aimed at increasing the amount of nursery habitat available for larval Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris . We examined the response of larval suckers to this large scale wetland restoration project at the Williamson River Delta by assessing discrepancies in catch rates, habitat preferences, and fish condition (size and gut fullness) at restored and existing lakeshore fringe wetlands. Differences in habitat associations existed between the two wetland types, as larval suckers preferred shallow, vegetated areas in the restored areas of the Williamson River Delta while in existing wetlands deep, non vegetated areas were occupied more frequently. Mean larval sucker length and gut fullness in the restored areas were on average greater than means in existing wetlands, a strong indication that larvae were rearing in the restored wetlands of the Williamson River Delta. Our monitoring suggests that wetland restoration efforts at the Williamson River Delta may contribute to the recovery of these two endangered species through the increase of larval nursery habitat. iii Project Background larval sucker behavior have concentrated on depth and vegetative cover as two In 1988 Lost River sucker important components of larval rearing Deltistes luxatus and shortnose sucker habitat. Larval suckers show a strong Chasmistes brevirostris were listed as preference for emergent macrophytes, endangered by the U.S. Fish and which may promote good year class Wildlife Service (US Fish and Wildlife formation (Cooperman and Markle Service 1988). Several factors were 2004) and are important for protection referred to as key causes for the severe from non-native species, including the population decline in the Upper Klamath fathead minnow Pimephales promelas Basin including habitat loss, water (Markle and Dunsmoor 2007). management, nonnative species, poor Emergent macrophytes also provide water quality, and overfishing (US Fish better feeding and growth opportunities and Wildlife Service 2002). Endemic to (Buettner and Scoppettone 1990; the large, eutrophic lakes of the upper Crandall et al. 2008; Hendrixson 2008), Klamath River watershed of Oregon and and allow for greater retention from the California, these two species are large, clockwise lake circulation pattern which long lived, adfluvial fish. Prior to the can lead to emigration from the lake 1940s, Lost River and shortnose suckers, (Markle et al. 2009). along with a third catastomid species, Restoring wetland complexity the Klamath largescale sucker with regards to vegetation and hydrology Catostomus snyderi , were abundant and to the Williamson River Delta and the widespread within their range and northern portions of Upper Klamath heavily relied upon by local Indians and Lake was identified as a high priority for settlers (US Fish and Wildlife Service recovering endangered suckers (National 1993). Today, the largest remaining Research Council 2004). Before being populations of Lost River sucker and diked and drained during the 1940s and shortnose sucker inhabit Upper Klamath 50s for agricultural purposes, the lower Lake (Buettner and Scoppettone 1990). five kilometers of the Williamson River Recently, recruitment to the adult life was a complex system containing history stage in the Upper Klamath Lake wetland vegetation, providing important populations has been sporadic, a possible connectivity between the lake and the consequence of the large reduction in river and valuable rearing habitat for rearing habitat for larvae, age-0, and larval suckers. Without this expansive age-1 suckers (National Research deltaic wetland, larvae rapidly exited the Council 2004). Williamson River and often entered By 1968, littoral marsh habitat Upper Klamath Lake without the adjacent to Upper Klamath Lake had development of a tail fin, causing decreased to ~7,000 hectares, a difficulties in foraging and swimming reduction of roughly 66% and a loss of (Cooperman and Markle 2000). habitat that has been cited as a principal Throughout this 2,200 hectare delta, the reason for the declining populations of river channel was u-shaped, dynamic, Lost River sucker and shortnose sucker and lined with critical larval fish habitat in the lake (US Fish and Wildlife (Cooperman and Markle 2003; TNC Service 2002). Studies focusing on unpublished data). 1 The Nature Conservancy collected during previous sampling purchased the northern portion of the seasons and outside project sites. By Williamson River Delta in 1996 determining the extent of larval use and (formerly called Tulana Farms and habitat preferences within the Delta, our referred to as Tulana) and the southern 2008 monitoring assessed the response portion in 1999 (formerly called Goose of larval suckers to large scale wetland Bay Farms and referred to as Goose restoration. Given the results from 2006 Bay) to create the Williamson River and 2007, we hypothesized that larval Delta Preserve (WRDP, referred to as suckers would utilize habitats in the the Delta). The Nature Conservancy Tulana portion of the Delta and would initiated three small-scale wetland prefer shallow water, vegetated areas restoration projects in the late 1990s to over deeper water, non-vegetated areas. study the response of larval suckers to wetland restoration. Monitoring at these Methods sites (Riverbend, South Marsh, and Campfields) since 2000 indicates that Sampling Design larval suckers are using these areas and In 2008 we conducted larval wetland restoration provides critical sucker sampling at five locations on the emergent wetland habitat, which can Delta: two early action projects lead to larger, more abundant, and (Riverbend and South Marsh), existing better-fed larval suckers (Crandall et al. lake fringe wetlands in two sections of 2008; Hendrixson 2008). Due to the Goose Bay (Goose Bay east and west; success of these projects, The Nature GBE, GBW), and the newly restored Conservancy restored the entire northern Tulana portion of the Delta (Figure 1). half of the Delta (Tulana) in October We divided Goose Bay into two distinct 2007. Roughly two miles of levees were sampling locations because the eastern breached, flooding ~1,500 hectares of section of Goose Bay could act as an old agricultural fields and reconnecting accumulation point for larvae, an the Williamson River and Upper anomaly thought to be caused by the Klamath Lake to former deltaic wetlands clockwise circulation of water in Upper on the Delta. Klamath Lake whereas the western In 2008 we continued larval section acts more like a conduit for sucker monitoring in Riverbend and suckers leaving the Williamson River South Marsh, at lake fringe wetlands (Wood and Cheng 2006; Markle et al. along the Goose Bay shoreline of Upper 2009). Klamath Lake, and expanded our Every other week beginning 27 monitoring efforts to the newly restored May, we conducted sampling in all five Tulana portion of the Delta. Our four sampling locations—this sampling effort main