Columbia River Project Water Use Plan. Lower Columbia River Fish Management

Transcription

1 Columbia River Project Water Use Plan Lower Columbia River Fish Management Implementation Year 2 Reference: CLBMON-45 Addendum Lower Columbia River Fish Indexing Survey Study Period: 2008 Golder Associates Ltd. June 7, 2010

2 LARGE RIVER FISH INDEXING PROGRAM Lower Columbia River Fish Indexing Survey Phase 8 Revised Addendum Submitted to: BC Hydro Power Supply Environmental Services 6911 Southpoint Drive (E16) Burnaby, British Columbia V3N 4X8 ADDENDUM Report Number:

3 Table of Contents 1.0 INTRODUCTION METHODS RESULTS Mountain Whitefish Rainbow Trout Walleye DISCUSSION RECOMMENDATIONS LITERATURE CITED... 6 TABLES Table 1: Table 2: Average number of invertebrates recorded (with percent of age by taxa in brackets) by size-class from the stomach contents of fish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Average number of invertebrates recorded (with percent of reach by taxa in brackets) by reach from the stomach contents of fish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November APPENDICES APPENDIX A Stomach Content - Raw Data Report No i

4 1.0 INTRODUCTION As a component of Phase 8 of BC Hydro s Large River Fish Indexing Program for the Lower Columbia River (CLBMON-45), stomach contents were collected from randomly selected fish for detailed analysis. These data were not available in time for inclusion in the 2008 final report (submitted to BC Hydro on 30 April 2009) and are detailed in this addendum. This addendum is a supplement to the Lower Columbia River Fish Indexing Survey 2008 Phase 8 Investigations final report. For information on sample methodologies, site locations, analytical techniques, results, or any other aspects of the program please refer to the final report: Golder Associates Ltd Large River Fish Indexing Program Lower Columbia River 2008 Phase 8 Investigations. Report prepared for BC Hydro, Burnaby, B.C. Golder Report No p. + 6 app 2.0 METHODS In order to compare results from the stomach content analysis with results from BC Hydro s Lower Columbia River Physical Habitat and Ecological Productivity Monitoring Program (CLBMON-44; TG Eco-Logic 2009) data were grouped by river reach for some of the analysis. Defined reaches in the LCR are: Reach 1 HLK (RKm 0.0) downstream to the confluence of Norn s Creek (RKm 7.5); Reach 2 Norn s Creek confluence downstream to the confluence of the Kootenay River (RKm 11.0); and, Reach 3 Kootenay River confluence downstream to the Canada-US border (RKm 56.5). After fish were sampled for life history information (Golder 2009a) stomach contents from randomly selected mountain whitefish, rainbow trout, and walleye were collected by gastric lavage (Bowen 1989, Brosse et al. 2002, Baldwin et al. 2003, Budy et al. 2007) using an apparatus modified from that described by Light et al. (1983). The apparatus consisted of a pressurised sprayer and wand fitted with a tubing adapter soldered to the adjustable spray nozzle from the bottle. Intravenous tubing and small diameter feeding tubes, both supplied by a veterinary office, were selected to match the mouth opening of the fish. The sprayer reservoir was filled with river water and pressurised using the hand pump. The free end of the tubing was inserted into the fish s mouth and gently inserted down into the stomach. The fish was held, head down, over a 250 µm mesh sieve to capture discharge during lavage. The flow of water was then opened using the flow control lever on the spray handle. The small diameter of the tubing served to regulate the flow at a pressure that did not damage the internal organs of the fish. Each fish s stomach was flushed with river water for approximately 30 seconds until the water exiting the fish s mouth ran clear. The tubing was gently extracted from the stomach and mouth with the water still flowing to ensure that all stomach contents were flushed from the buccal cavity. Sampled fish were returned to the river. The collected sample was washed from the sieve into a collection jar and preserved in 10% formalin for later identification and enumeration of contents. Stomach contents were analyzed by Limnotek Research and Development Inc. (Vancouver, BC). Contents were identified to the lowest reliable taxon (family level for most taxa) and counted. Head counts were used for the enumeration of partly digested animals. Each identifiable fish retrieved from stomach contents was counted. Fish parts in advanced stages of digestion that could not be discriminated (e.g. a milieu of muscle tissue) were counted as a single fish. A sub-sample of randomly selected mountain whitefish, rainbow trout, and walleye were sacrificed after conducting gastric lavage. Stomachs were collected from these individuals to determine the efficiency of the Report No

5 gastric lavage procedure. Although these samples were collected for all three indexing species, only samples collected from walleye have been analyzed during the current program. Samples collected from mountain whitefish and rainbow trout are available for future analysis. 3.0 RESULTS The following results provide specific information by fish species. A taxonomic list of all organisms recorded during stomach content analysis is provided in Appendix A, Table A Mountain Whitefish For mountain whitefish (n = 20), the bulk of the sample composition (based on item counts) from each fish consisted of terrestrial and aquatic invertebrates. Zooplankton were the most abundant invertebrates recorded (44.1% of the total individual invertebrate counts in the catch; Table 1); however, 99.5% of the total zooplankton catch was from two age-0 mountain whitefish captured on 10 October in site ES19 (i.e., Reach 1). Larval EPT (aquatic insects from the Ephemeroptera, Plecoptera, or Trichoptera orders) were the second most abundant invertebrates (33.5%), followed by chironomids (16.8%), and mysids (4.6%). All other invertebrates combined represented 1.2% of the total invertebrate catch; these included (in descending order of abundance) Diptera, Hemiptera, Isopoda, Amphipoda, Araneae, Trombidiformes, Heterostropha, Basommatophora, and Veneroida. Other material found in mountain whitefish stomach samples included fish scales (recorded in three individuals), rocks and/or Trichoptera cases (recorded in six individuals), gemmules (recorded in three individuals), and plant material (recorded in two individuals). Table 1: Average number of invertebrates recorded (with percent of age by taxa in brackets) by sizeclass from the stomach contents of fish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Species Size-class n a Average number of invertebrates (percent of taxa in brackets) All Other Aquatic Terrestrial Chironomids EPT b Zooplankton c Invertebrates Taxa d Taxa e Mountain Age (96.6) 27 (6.7) (99.4) 3.2 (5.0) 1 (50.0) 754 (62.7) whitefish Age (2.4) (23.3) 2 (0.3) 0 (0.0) 0 (0.0) (8.4) Age (1.0) (70.0) 0.6 (0.3) 27.8 (95.0) 0.5 (50.0) 158 (28.9) All Rainbow <300 mm FL (77.6) (85.0) (79.2) 22.4 (78.0) trout >300 mm FL 11 7 (22.4) (15.0) (20.8) 5.2 (22.0) All Walleye All a b c d e n = total number of fish sampled. includes Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies). includes cladocerans (Daphnia species and Eurycercus species) and copepods (Cyclops species). includes non-chironomid Diptera, Hemiptera, Isopoda, Amphipoda, Mysida, Trombidiformes, Heterostropha, Basommatophora, and Veneroida. includes Diptera, Lepidoptera, Neuroptera, Hymenoptera, Coleoptera, Hemiptera, and Araneae. Report No

6 Overall, age-0 mountain whitefish tended to ingest more larval chironomids (average of 195 chironomids per sample) than age-1 and age-2+ fish (averages of 6 and <1 chironomid per sample, respectively; Table 1). Age-1 and older mountain whitefish tended to ingest more EPT invertebrates (average of 125 EPT invertebrates per sample) than age-0 fish (average of 27 EPT invertebrates per sample; Table 1). All mysids collected (n = 279) were from age-2 individuals (Appendix A, Table A2). Stomach samples were analyzed from mountain whitefish captured in Reach 1 (n = 3), Reach 2 (n = 6), and Reach 3 (n = 11). Hydropsychidae (Trichoptera order) were not recorded in stomach samples collected in Reach 1, but were present in samples collected in Reach 2 and Reach 3 (average of 86 and 111 organisms per sample, respectively; Appendix A, Table A2). This result is consistent with results from CLBMON-44 (TG Eco-Logic 2009), which indicated lower abundance of Trichoptera in Reach 1 relative to Reaches 2 and 3. Chironomids, which were most abundant in Reach 2 during CLBMON-44 (TG Eco-Logic 2009), were least abundant in Reach 2 during the current program (Table 2). Zooplankton were more abundant in Reach 1 (average of 879 organisms per sample) than in Reach 2 (average of 2.5 organism per sample) and Reach 3 (zooplankton were not recorded in samples collected in Reach 3; Table 2). Zooplankton was not sampled during CLBMON-44 (TG Eco-Logic 2009) and could not be compared to results of the current program. Table 2: Average number of invertebrates recorded (with percent of reach by taxa in brackets) by reach from the stomach contents of fish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Species Mountain whitefish Rainbow trout Walleye Average number of invertebrates (percent of taxa in brackets) Reach n a Other Aquatic Terrestrial Chironomids EPT b Zooplankton c Total Taxa d Taxa e Invertebrates (3.6) 0.3 (<0.1) (99.4) 1.7 (1.6) 1.3 (40.0) (44.7) (2.1) 86 (25.6) 2.5 (0.6) 26.7 (49.7) 0 (0.0) (11.8) (94.4) (74.3) 0 (0.0) 14.3 (48.8) 0.5 (60.0) (43.5) All (1.2) 13 (0.2) 0 (0.0) 27 (98.2) 0 (0.0) 42 (0.7) (98.8) (99.8) 0 (0.0) 0.1 (1.8) 14.4 (100.0) (99.3) All (0.0) 0.8 (43.3) 0 (100.0) 1 (69.6) 0.1 (66.7) 2 (47.7) (0.0) 0.5 (1.7) 0 (0.0) 0 (0.0) 0 (0.0) 0.5 (0.8) (100.0) 0.8 (46.7) 0 (0.0) 0.4 (30.4) 0 (33.3) 1.7 (47.7) Kootenay 9 0 (0.0) 0.6 (8.3) 0 (0.0) 0 (0.0) 0 (0.0) 0.6 (3.9) All a b c d e n = total number of fish sampled. includes Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies). includes cladocerans (Daphnia species and Eurycercus species) and copepods (Cyclops species). includes non-chironomid Diptera, Hemiptera, Isopoda, Amphipoda, Mysida, Trombidiformes, Heterostropha, Basommatophora, and Veneroida. includes Diptera, Lepidoptera, Neuroptera, Hymenoptera, Coleoptera, Hemiptera, and Araneae. Report No

7 3.2 Rainbow Trout For rainbow trout (n = 20), the bulk of the samples consisted of terrestrial and aquatic invertebrates. Ephemeroptera were the most abundant invertebrate (83.5% of the total invertebrate catch), followed by Trichoptera (8.2%), Mysids (3.2%), Chironomids (2.6%), and Hemiptera (1.3%). All other invertebrates combined represented 1.1% of the total invertebrate catch; these included (in descending order of abundance) Diptera, Lepidoptera, Neuroptera, Hymenoptera, Coleoptera, Amphipoda, Araneae, Trombidiformes, Cyclopoida, and Basommatophora (Appendix A, Table A3). Other material found in rainbow trout stomach samples included fish scales (recorded in five individuals), gemmules (recorded in five individuals), seeds (recorded in four individuals), plant material (recorded in three individuals), and rocks and/or Trichoptera cases (recorded in two individuals; Appendix A, Table A3). Invertebrate counts (most notably Ephemeroptera) were higher for rainbow trout <300 mm FL (average of 1220 invertebrates per sample) and lower for rainbow trout >300 mm FL (average of 183 invertebrates per sample; Table 1). Reasons for this result are unknown, but could be related to diet composition; larger rainbow trout are piscivorous and would therefore ingest fewer invertebrates than smaller rainbow trout. Fish were not recorded in any rainbow trout stomachs; however, all fish scales (n = 14) present in the stomach content samples were recorded in the stomachs of larger individuals (Appendix A, Table A3). During field sampling, approximately 87% of the total rainbow trout catch occurred in Reach 3, as such, the bulk (n = 18) of rainbow trout stomach samples were from fish captured in Reach 3 (samples were not analyzed from Reach 1, and 2 samples were analyzed from Reach 2). Although not statistically tested, data did not suggest a relationship between food composition and capture location for these samples. Additional stomach samples are available if further analysis is requested. 3.3 Walleye Stomach content analysis for walleye was based on the contents of 77 samples collected by gastric lavage and on the contents of 15 stomachs (i.e., collected after field crews performed gastric lavage; Appendix A, Table A4). In total, 113 invertebrates were recorded in the 77 samples. Of the 113 invertebrates, 60 (53.1%) were EPT invertebrates and 21 (18.6%) were Mysids (Appendix A, Table A4). Other ingested invertebrates included Chironomids (n = 18), Isopoda (n = 8), Gastropoda (n = 3), Amphipoda (n = 1), Hemiptera (n = 1), and zooplankton (n = 1; Appendix A, Table A4). Fish (n = 210) were recorded in 73 of 77 walleye stomachs (94.8%). Out of the 210 fish recorded, 7 were sculpin species; the remaining 203 fish could not be identified to species. The average number of individual fish recorded in each sample was 3.0 fish (range from 0 to 10 individuals). Other material found in the stomach samples included fish scales (recorded in 13 individuals), parasites (recorded in 7 individuals), pine needles, feathers, or sticks (recorded in 4 individuals), plant material (recorded in 3 individuals), and rocks and/or Trichoptera cases (recorded in 1 individual; Appendix A, Table A4). All sculpin were recorded in walleye stomachs collected in Reach 3 (average of 0.2 sculpin per sample based on 35 stomachs). Out of the 210 fish recorded in walleye stomachs, 140 were recorded in Reach 1, 60 were recorded in Reach 3, 8 were recorded in the Kootenay River, and 2 were recorded in Reach 2. On average, samples from Reach 1 had more fish present (average of 4.5 fish per sample based on 31 stomachs) than samples from Reach 2 (average of 1 fish per sample based on 2 stomachs) and Reach 3 (average of 1.7 fish per sample based on 35 stomachs) and the Kootenay River (average of 0.9 mountain whitefish per sample based on 9 stomachs). The higher number of fish present in samples from Reach 1 supports other results from BC Hydro s Large River Fish Indexing Program (CLBMON-45; Golder 2009a), which show higher abundances of potential prey fish Report No

8 (e.g., immature kokanee, mountain whitefish, northern pikeminnow, rainbow trout, and sucker species, and all life stages of redside shiner and sculpin species) in Reach 1 relative to other sections of the study area. To determine the efficiency of gastric lavage on walleye, a sub-sample of 13 stomachs were collected from walleye immediately after field crews conducted gastric lavage on the fish (Appendix A, Table A5). Invertebrates were not recorded in any walleye stomachs (i.e., gastric lavage was 100% efficient at collecting invertebrates from walleye stomachs). Out of 47 fish present in the 13 stomachs, 38 were removed by gastric lavage (80.9%). Out of 50 fish scales present in the 13 stomachs, 24 were removed by gastric lavage (48.0%; Appendix A, Table A5). 4.0 DISCUSSION Overall, zooplankton were relatively uncommon in stomach samples collected during the current program. All zooplankton that were recorded were collected from fish captured upstream of the Kootenay River confluence, suggesting that these fish were feeding on zooplankton entrained through HLK. Two age-0 mountain whitefish sampled in Reach 1 ingested over 99% of all zooplankton ingested by mountain whitefish. These two fish also ingested relatively few Chironomids and Trichopterans, major components of the diet of age-0 mountain whitefish sampled in Reach 3 (n = 3; Appendix A, Table A2). Although based on few data points, the possibility of a reach-specific diet may help explain the slower growth rate for age-0 mountain whitefish captured in the upper portions of the study area (i.e., Reaches 1 and 2) relative to the lower portions (i.e., Reach 3; Figure 12 in Golder 2009a). Mysids are not native to the Lower Columbia River. Out of the 29 stomach samples which contained mysids, 7 were collected from fish upstream of the Kootenay River, suggesting that these mysids were entrained through HLK. The remaining 22 stomach samples which contained mysids were collected from fish downstream of the Kootenay River confluence; these mysids could therefore have been entrained from either Arrow Lakes Reservoir or Kootenay Lake. The presence of fish in 94.8% of all walleye stomach samples indicates that this species is a major predator in the study area. However, based on available data, it is impossible to determine the impact of walleye predation on the population abundance of key index species. 5.0 RECOMMENDATIONS In considerations of the findings above and the overall objectives of the Large River Fish Indexing Program for the Lower Columbia River, the following recommendations are provided (in addition to those provided in the final report; Golder 2009a): Additional samples collected during Phase 8 of the program should be analyzed. This would provide a larger dataset to support or discount the above findings. For mountain whitefish and rainbow trout, a comparison should be made between stomach content samples collected by gastric lavage and stomach samples collected from sacrificed individuals. This would help determine the efficiency of gastric lavage on these species. Stomach content samples should continue to be collected during Phase 9 of the program. To compare relative importance of taxa in the diet of the fish species studied, future phases of the program should include length measurements of a sample of invertebrates with appropriate length-weight Report No

9 conversion functions to estimate biomass for each taxa. This is necessary to provide comparisons of the importance of each taxa in the diet of fish relative to their abundance in the Columbia River as established by invertebrate studies currently being conducted in the same area (CLBMON-44). Field personnel should enumerate and identify fish recorded in the stomach contents of walleye while in the field. It is possible that a higher percentage of fish could be positively identified to species if they were analyzed prior to preservation. In addition, data collected on potential prey fish during the boat electroshocking survey, could be used as an aid in species identification. The abundance of invertebrates in walleye stomach contents is generally low; however, these organisms could still be store for future analysis. 6.0 LITERATURE CITED Baldwin, CM, JG McLellan, MC Polacek, and K. Underwood Walleye Predation on Hatchery Reared Rainbow Trout in Lake Roosevelt, Washington. North American Journal of Fisheries Management. 23: Bowen, SH Quantitative Description of the Diet. In: Nielsen, LA and DL Johnson (eds). Fisheries Techniques, Third Edition. American Fisheries Society. Bethesda, Maryland. Bromley, P.J The role of gastric evacuation experiments in quantifying the feeding rates of predatory fish. Reviews in Fish Biology and Fisheries, 4, (1994) Brosse, L., P. Dumont, M. Lepage, and E. Rochard Evaluation of a Gastric Lavage Method for Sturgeons. North American Journal of Fisheries Management. 22: Budy, P., R. Al-Chokhachy, and GP Thiede Bull Trout Population Assessment in Northeastern Oregon: A Template for Recovery Planning. USGS Utah Cooperative Fish and Wildlife Research Unit. Department of Aquatic, Watershed, and Earth Resources Utah State University, Logan, Utah Golder Associates Ltd. 2009a. Large River Fish Indexing Program Lower Columbia River 2008 Phase 8 Investigations. Report prepared for BC Hydro, Burnaby, B.C. Golder Report No p. + 6 app Golder Associates Ltd. 2009b. Lower Columbia River whitefish life history and egg mat monitoring program: investigations data report. Report prepared for BC Hydro, Castlegar, BC Golder Report No F: 42 p. + 6 app. Light, RW, PH Adler, and DE Arnold Evaluation of Gastric Lavage for Stomach Analyses. North American Journal of Fisheries Management. 3: TG Eco-Logic, LLC Lower Columbia River Physical Habitat and Ecological Productivity Monitoring 2008 Report. Report prepared for BC Hydro, Castlegar, BC. 52 p. + 7 app Report No

10 Report Signature Page Dustin Ford, R.P. Bio., B.Sc. Project Biologist Larry Hildebrand, R.P.Bio., B.Sc. Project Advisor DF/DS/cmc c:\documents and settings\cmcallister\desktop\ lcr fish indexing phase 8 revised addendum.docx Report No

11 APPENDIX A Stomach Content - Raw Data Report No

12 Table A1 Taxonomic coding used in the analysis of stomach contents collected from fish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Phylum Subphylum Class Subclass Infraclass Superorder Order Suborder Infraorder Superfamily Family Genus Species Source Stage Code arthropoda hexapoda insecta pterygota neoptera diptera brachycera muscomorpha muscidae Terrestrial Adult s01 arthropoda hexapoda insecta pterygota neoptera diptera nematocera bibionomorpha sciaridae Terrestrial Adult s02 arthropoda hexapoda insecta pterygota neoptera diptera brachycera muscomorpha tachinidae Terrestrial Adult s03 arthropoda hexapoda insecta pterygota neoptera diptera nematocera bibionomorpha mycetophilidae Terrestrial Adult s04 arthropoda hexapoda insecta pterygota neoptera diptera nematocera culicomorpha simuliidae Terrestrial Adult s05 arthropoda hexapoda insecta pterygota neoptera diptera nematocera culicomorpha simuliidae Aquatic a Pupae s06 arthropoda hexapoda insecta pterygota neoptera diptera nematocera culicomorpha simuliidae Aquatic a Larval s07 arthropoda hexapoda insecta pterygota neoptera diptera Chironomids b Adult s08 arthropoda hexapoda insecta pterygota neoptera diptera nematocera culicomorpha chironomidae Chironomids b Larval s09 arthropoda hexapoda insecta pterygota neoptera diptera nematocera culicomorpha chironomidae Chironomids b Pupae / Adult s10 arthropoda hexapoda insecta pterygota palaeoptera ephemeroptera EPT c Adult s11 arthropoda hexapoda insecta pterygota palaeoptera ephemeroptera ephemerellidae Drunella spinifera/grandis EPT c Larval s12 arthropoda hexapoda insecta pterygota palaeoptera ephemeroptera baetidae EPT c Larval s13 arthropoda hexapoda insecta pterygota neoptera trichoptera hydropsychidae EPT c Larval s14 arthropoda hexapoda insecta pterygota neoptera trichoptera rhyacophilidae EPT c Larval s15 arthropoda hexapoda insecta pterygota neoptera trichoptera brachycentridae EPT c Larval s16 arthropoda hexapoda insecta pterygota neoptera trichoptera glossosomatidae EPT c Larval s17 arthropoda hexapoda insecta pterygota neoptera trichoptera psychomyidae EPT c Larval s18 arthropoda hexapoda insecta pterygota neoptera trichoptera polycentropodidae EPT c Larval s19 arthropoda hexapoda insecta pterygota neoptera trichoptera EPT c Pupae s20 arthropoda hexapoda insecta pterygota neoptera trichoptera EPT c Emerging adult s21 arthropoda hexapoda insecta pterygota neoptera lepidoptera Terrestrial Adult s22 arthropoda hexapoda insecta pterygota neoptera neuropterida neuroptera hemerobiiformia chrysopidae Terrestrial Adult s23 arthropoda hexapoda insecta pterygota neoptera neuropterida neuroptera hemerobiiformia hemerobiidae Terrestrial Adult s24 arthropoda hexapoda insecta pterygota neoptera hymenoptera apocrita terebrantes ichneumonoidea Terrestrial Adult s25 arthropoda hexapoda insecta pterygota neoptera hymenoptera apocrita terebrantes chalcidoidea Terrestrial Adult s26 arthropoda hexapoda insecta pterygota neoptera hymenoptera apocrita aculeata vespoidea Terrestrial Adult s27 arthropoda hexapoda insecta pterygota neoptera hymenoptera apocrita terebrantes proctotrupoidea diapriidae Terrestrial Adult s28 arthropoda hexapoda insecta pterygota neoptera hymenoptera apocrita aculeata vespoidea formicidae Terrestrial Adult s29 arthropoda hexapoda insecta pterygota neoptera coleoptera polyphaga staphyliniformia staphylinoidea staphylinidae Terrestrial Adult s30 arthropoda hexapoda insecta pterygota neoptera coleoptera adephaga carabidae Terrestrial Adult s31 arthropoda hexapoda insecta pterygota neoptera coleoptera polyphaga cucujiformia curculionoidea curculionidae Terrestrial Adult s32 arthropoda hexapoda insecta pterygota neoptera coleoptera Terrestrial Adult s33 arthropoda hexapoda insecta pterygota neoptera hemiptera sternorrhyncha aphidoidea aphididae Terrestrial Adult s34 arthropoda hexapoda insecta pterygota neoptera hemiptera auchenorrhyncha cicadomorpha cicadelloidea cicadellidae Terrestrial Adult s35 arthropoda hexapoda insecta pterygota neoptera hemiptera heteroptera nepomorpha corixoidea corixidae Aquatic a Adult s36 arthropoda hexapoda insecta pterygota neoptera hemiptera auchenorrhyncha fulgoromorpha fulgoroidea cixiidae Terrestrial Adult s37 arthropoda hexapoda insecta pterygota neoptera hemiptera heteroptera gerromorpha hebroidea hebridae Terrestrial Adult s38 arthropoda hexapoda insecta pterygota neoptera hemiptera heteroptera cimicomorpha miroidea miridae Terrestrial Adult s39 arthropoda hexapoda insecta pterygota neoptera hemiptera heteroptera cimicomorpha cimicoidea nabidae Terrestrial Adult s40 arthropoda hexapoda insecta pterygota neoptera hemiptera heteroptera pentatomomorpha coreoidea coreidae Terrestrial Adult s41 arthropoda crustacea malacostraca eumalacostraca peracarida Isopoda oniscidea ligiamorpha armadilloidea porcellionidae Porcellio scaber Aquatic a s42 arthropoda crustacea malacostraca eumalacostraca peracarida Isopoda asellota aselloidea asellidae Asellus Aquatic a s43 arthropoda crustacea malacostraca eumalacostraca peracarida amphipoda gammaridea crangonyctidae Crangonyx Aquatic a s44 arthropoda crustacea malacostraca eumalacostraca peracarida mysida mysidae Mysis relicta Aquatic a s45 arthropoda chelicerata arachnida araneae Terrestrial s46 arthropoda chelicerata arachnida acari acariformes trombidiformes prostigmata lebertiidae Lebertia Aquatic a s47 arthropoda crustacea branchiopoda phyllopoda diplostraca cladocera anomopoda daphniidae Daphnia Zooplankton s48 arthropoda crustacea branchiopoda phyllopoda diplostraca cladocera anomopoda chydoridae Eurycercus Zooplankton s49 arthropoda crustacea maxillopoda copepoda neocopepoda podoplea cyclopoida cyclopidae Cyclops Zooplankton s50 mollusca gastropoda Terrestrial s51 mollusca gastropoda heterostropha valvatidae Valvata Aquatic a s52 mollusca gastropoda basommatophora lymnaeidae Aquatic a s53 mollusca gastropoda basommatophora physidae Physa/Physella Aquatic a s54 mollusca bivalvia heterodonta veneroida corbiculoidea pisidiidae Pisidium Aquatic a s55 a Aquatic other than chironomids and EPT. b Chironomids in aquatic habitat. c Includes aquatic insects from the Ephemeroptera, Plecoptera, or Trichoptera orders.

13 Table A2 Number of invertebrates recorded in the stomach contents of mountain whitefish captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Invertebrates b Other Sample Number Fork Length (mm) Age Site a Date s02 s05 s06 s07 s09 s10 s11 s12 s13 s14 s15 s16 s17 s18 s20 s34 s35 s36 s43 s44 s45 s46 s47 s48 s49 s50 s52 s53 s55 Total Fish Scales Trichoptera Cases or Rocks Gemmules ALGAL clump, moss, or plant material ES09 9-Oct ES09 9-Oct ES09 9-Oct ES19 10-Oct ES19 10-Oct ES19 10-Oct ES Oct ES Oct ES10 17-Oct ES10 17-Oct ES10 17-Oct ES17 19-Oct ES17 19-Oct ES17 19-Oct ES17 19-Oct ES17 19-Oct ES25 19-Oct ES09 22-Oct ES Oct ES Oct Total a See Golder 2009a (Appendix B, Figures B1 to B3) for sample site locations. b See Appendix A, Table A1 for details on taxonomic coding.

14 Table A3 Number of invertebrates recorded in the stomach contents of rainbow trout captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Invertebrates b Other Sample Number Fork Length (mm) Age Site a Date s01 s04 s05 s06 s07 s08 s09 s10 s11 s12 s13 s14 s16 s19 s20 s21 s22 s23 s24 s25 s26 s27 s28 s29 s30 s31 s32 s33 s34 s35 s36 s37 s38 s39 s40 s41 s44 s45 s46 s47 s51 s53 s54 Total Fish Scales Trichoptera Cases or Rocks Gemmules Seeds ALGAL clump, moss, or plant material ES10 22-Oct ES10 17-Oct ES09 9-Oct ES09 9-Oct ES09 22-Oct ES09 9-Oct ES09 22-Oct ES09 9-Oct ES09 9-Oct ES09 9-Oct ES17 19-Oct ES09 9-Oct ES17 19-Oct ES10 17-Oct ES10 22-Oct ES09 9-Oct ES09 9-Oct ES09 17-Oct ES09 9-Oct ES09 9-Oct Total a See Golder 2009a (Appendix B, Figures B1 to B3) for sample site locations. b See Appendix A, Table A1 for details on taxonomic coding.

15 Table A4 Number of invertebrates recorded in the stomach contents of walleye captured by boat electroshocking in the Lower Columbia River, 22 September to 3 November Sample Number Total Fork Length (mm) Site a Date Invertebrates b s09 s12 s14 s16 s20 s36 s42 s44 s45 s48 s51 s52 Total Sculpin Species Unidentified Fish Fish Scales Trichoptera Cases or Rocks Parasites Pine needles, Sticks, or Feathers ES08 8-Oct ES08 8-Oct ES09 9-Oct ES09 9-Oct ES19 10-Oct ES19 10-Oct ES28 10-Oct ES28 10-Oct ES28 10-Oct ES19 10-Oct ESK2 11-Oct ES Oct ES2A 15-Oct ES2A 15-Oct ES2A 15-Oct ES2A 15-Oct ES2B 15-Oct ES9 17-Oct ES9 17-Oct ES20 18-Oct ES19 18-Oct ES17 19-Oct ES25 19-Oct ES1A 21-Oct ES1A 21-Oct ES1A 21-Oct ES1A 21-Oct ES10 22-Oct ES10 22-Oct ES10 22-Oct ES Oct ES Oct ES Oct ES Oct ES29 24-Oct ES29 24-Oct ES29 24-Oct ES29 24-Oct ES21 24-Oct ES21 24-Oct ES21 24-Oct ES21 24-Oct ES21 24-Oct ES20 24-Oct ESK1 25-Oct ESK1 25-Oct ESK1 25-Oct ESK2 25-Oct ESK2 25-Oct ESK2 25-Oct ESK2 25-Oct ESK2 25-Oct ES Oct ES Oct ES Oct ES Oct ES Oct ES Oct ES1A 29-Oct ES1A 29-Oct ES1A 29-Oct ES8 30-Oct ES8 30-Oct ES8 29-Oct ES29 2-Nov ES29 2-Nov ES22 2-Nov ES22 2-Nov ES21 2-Nov ES21 2-Nov ES21 2-Nov ES21 2-Nov ES21 2-Nov ES21 2-Nov ES20 2-Nov ES19 2-Nov ES19 2-Nov Other ALGAL Clump, Moss, or Plant Material a See Golder 2009a (Appendix B, Figures B1 to B3) for sample site locations. b See Appendix A, Table A1 for details on taxonomic coding.

16 Table A5 Details of food items removed by gastric lavage and recovered by stomach collection for walleye captured by boat electroshocking in the Lower Columbia River. All fish were collected on 2 November Invertebrates a Other a Sample Number Fork Length (mm) Sample Type s44 s45 s48 s51 s52 Total Unidentified Fish Fish Scales Parasites Pine needles, Sticks, or Feathers Comments gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection Stomach was empty gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection gastric lavage stomach collection Stomach was empty a See Appendix A, Table A1 for details on taxonomic coding.

17 Golder Associates Ltd. 201 Columbia Avenue Castlegar, British Columbia, V1N 1A8 Canada T: +1 (250)