Đánh giá tình trạng quần thể cá hạ lưu sông Bow

LOWER BOW RIVER FISH POPULATION STATUS ASSESSMENT - August 2000 - LOWER BOW RIVER FISH POPULATION STATUS ASSESSMENT August 2000 Prepared for ALBERTA ENVIRONMENT Natural Resources Service Fisheries and Wildlife Management Division Bow Region Strathmore, Alberta by RL&L ENVIRONMENTAL SERVICES LTD 17312 - 106 Avenue Edmonton, Alberta T5S 1H9 Phone: (780)483-3499 Fax: (780)483-1574 edmonton@rll.ca March 2001 Prinled on Recycled Paper Cover Photo: A member brown Suggested Citation: ot' Alberta Environment colleets a scale sample tor ageing purposes from a Bow River trout RL&L Environmental Services Ltd 2001 assessment - No 855F: 30 August 2000 p + app Low'er Bow River fish Prepared for Alberta Environment population status RL&L Report RL&L ENVIRONMENTAL SERVICES LTD ACKNOWLEDGEMENTS RL&L Environmental Services Ltd would Environment for initiating the project like to thank the staff like to thank Mr Trevor Rhodes and Mr Cam Wallman and for providing information and guidance during the study of Alberta Environment for their contributions to the data collection of Alberta We would also Funding was provided by the Alberta Conservation Association The following employees of RL&L Environmental Services Ltd contributed to the collection of data and/or preparation of this report: Lower Bow River Corey Stefura - Project Biologist, Author Jack Patalas - Report Editor Jim Campbell - Fisheries Biologist Scott Morrison - Fisheries Technician Charlene Williamson - Fisheries Technician Chantal Pattenden - Fisheries Technician Mike Braeuer - Fisheries Technician Rob Stack - Fisheries Technician Fish Population Status Assessment - August 2000 Page i Ri &! KN\ IKONMKN I \l SKK\ ICKS 1 1) TABLE OF CONTENTS Page P ACKNOVVLEDCEMENTS i LIST OF TABLES iii LIST OF FIGURES i\ 1.0 INTRODUCTION 2.0 METHODS STUDY ARHA AND SAMPLE PERIOD 2.2 RIVER CONDITIONS 2.3 FISH CAPTURE AND ASSESSMENT DATA ANALYSIS 2.1 2.4 2.4.1 Size-Classes 2.4.2 Catch Data 2.4.3 Life History 2.4.4 Population Estimates 3.0 RIVER CONDITIONS 4.0 SPECIES COMPOSITION 5.0 AND RELATIVE ABUNDANCE S SPECIES COMPOSITION K 4.2 RELATIVE ABUNDANCE S LIFE HISTORY DATA 13 5.1 SIZE DISTRIBUTION 13 5.2 13 5.4 FORK LENGTH TOTAL LENGTH RELATIONSHIPS LENGTH-WEIGHT RELATIONSHIPS AGE AND GROWTH 5.5 FISH INJURY INDICES IS - POPULATION ESTIMATES 6.1 BROWN TROUT 6.2 RAINBOW TROUT 6.3 MOUNTAIN WHITEFISH 6.4 7.0 4.1 5.3 6.0 FISH 16 16 20 21 24 24 MOVEMENTS 27 LITERATURE CITED 30 APPENDIX A Raw APPENDIX B CPUE APPENDIX C Population Estimate Data Data for Captured Fish Lower Bow River Fish Population and Life History Data Status Assessment - August 2000 Page ii RL&L ENVIRONMENTAL SERVICES LTD OF TABLES LIST Page # Table 2.1 Fin marking procedures for identifying capture date and location during the Bow River fish population assessment, August 2000 Table Table 3.1 Water temperature, conductivity, and mean daily discharge of the population assessment, August 2000 Sportfish species captured in the Table 4.2 Mean catch per unit effort sportfish captured in the Bow River, (CPUE Bow River during the fish August 2000 expressed as Bow River in August (RL&L 2000) fish/1 000s) and standard deviation (SD) for 2000 compared to similar data from 1990- 1992 (Courtney 1993) and 1999 Table 5.1 Number of River, Table 10 injured fish and causes recorded during fish population assessment in the Bow August 2000 18 Number of fish marked and recaptured during fish population assessment in the Bow River, August 2000 20 Table 6.2 Brown Table 6.3 Rainbow Table 6.4 Mountain whitefish population estimates Table 6.5 trout population estimates for the trout population estimates for the Summary of fish movements out of assessments, August 2000 Lower Bow River Bow River, Fish Population Status Assessment - Bow River, for the the August 2000 Bow August 2000 Bow River, August 2000 21 24 27 River study area during fish population 29 August 2000 Page iii R1 &1 LIST KNMRONMKM Al SKR\ 1C KS I 1) Page iv I OF FIGURES Page P Figure 2.1 Figure 4.1 Bow 20()() Relative abundance, expressed as catch-per-unit-eft'ort (C'PUF), of trout, Figure 4.2 River Study Area, August and mountain whitefish captured Comparison of brown (CPUE) trout, rainbow brown trout, rainbou in the liow River August trout, and mountain whitefish catch-per-unii-cffon 990- 992 (Courtney 993 ) 999 Rl.iicL indices recorded in the lk)w River during 1 2()()() 1 ( 2000) and during the present study (August 2000) Figure Length frequency distribution of brown by boat eleetrofishing Figure 5.2 the Bow trout, rainbow trout, and mountain whitefish captured River, August 2000 14 Fork length-weight regressions and fork length-total length relationships rainbow Figure 5.3 in trout, and mountain whitefish in the Bow River, Augu.st for brown trout, 2000 15 Age-length relationships for brown trout and rainbow trout captured in the Bow River August 2000 Figure 6.1 17 Comparison of brown 95% trout population estimates (± confidence intervals) calculated using the Darroeh method, 1982 to 2000 Figure 6.2 Comparison of brown 22 95% trout population estimates (± confidence intervals) calculated using the Null method, 1990 to 2000 Figure 6.3 Comparison of rainbow 23 trout population estimates (± 95% confidence intern als) calculated using the Darroeh method, 1982 to 2000 Figure 6.4 Comparison of rainbow 25 trout population estimates (± 95% confidence inter\ als) calculated using the Null method, 1990 to 2000 Figure 6.5 Lower Bow River moved by 26 brown trout, rainbow release and recapture locations in the Bow River, August Distance individual Fish Population Status Assessment - August 2000 trout, and mountain whitefish between 2000 28 RL&L ENVIRONMENTAL SERVICES LTD INTRODUCTION 1.0 The Lower Bow River near Calgary (downstream of Bearspaw Dam) provides an excellent sport fishery for rainbow trout {Oncorhynchus mykiss), brown trout {Salmo trutta), and mountain whitefish {Prosopium williamsoni) Fisheries studies conducted during the early 1980's assessed the status of brown trout and rainbow trout populations immediately downstream of Calgary (Sosiak and Griffiths 1983; Sosiak 1984) Based on these studies, regulations requiring anglers to release all trout greater than between Highway 22X bridge and the Carseland Weir number of large trout Fernet et al in the system 40 cm in length were implemented in 1983 new fishing in the section of river This regulation change was designed to increase the Monitoring studies were conducted between 1984 and 1992 (Sosiak et al 1988; 1988; Courtney and Fernet 1989, Courtney and Fernet 1990, Courtney and Fernet 1991; Helwig and Courtney 1993; Courtney 1993) to assess the effectiveness of these regulations In August 1999, Alberta Environment and to update the status RL&L Environmental Services Ltd (RL&L) conducted a fisheries study of the sportfish populations in the Lower Bow with the previous data of the 1980's and early 1990's in monitoring program Lower Bow River is The results of this study were compared (2000) Recognizing that the continuation of the necessary to assess the impact of fishing regulations and increasing recreational use on the sportfish populations, Alberta August 2000 Similar RL&L River Environment contracted to the objectives outlined in RL&L to assist in a follow-up survey in RL&L (2000), the main requirements of the present study were to: • derive population estimates (with confidence limits) for different size-classes of brown trout, rainbow trout, and mountain whitefish; • calculate catch-per-unit-effort • determine life (CPUE) indices for these size-classes and species; history data (length frequencies, length- weight regressions, condition factors, fork length to total length conversion factors, age-length relationships, injury indices, etc.) for the target species; • identify possible changes in fish populations over time by comparing the current data to corresponding data from previous years; and, • assess statistical assumptions inherent in mark/recapture methods (e.g., fish movement) Lower Bow River Fish Population Status Assessment - August 2000 Page Rl 2.0 STUDYAREA AND SAMPLE PERIOD The study area Bow Bearspaw Dam) and eorresponded named tributaries to the river section as.sessed in Kms 49.5 at ( (UTM NAD27) - ) IC KS I II) ol the There are no major The upstream and downstream boundaries of each the study area using a ( :20 Garmin 45 GPS unit The mean width (m) and area 000 on July scale) taken Fish Creek Provincial Park, located upstream of the conducted between SKK\ and 53.5 do\^nstreanl 999 Figure 1 998 As reported sampled area was approximately 36 within the 4-km study section The study launch Highway 22X site in (ha) of the study RL&L (2000) the was accessed using The bridge section field the boat sampling was and 24 August 2000 RIVER CONDITIONS 2.2 Water temperature the the City ofC'algary (between same 4-km to the sections were measured from air photos total in \l River within this river section This section was further divided into four 1-km sub- movements within sections to assess fish were geo-referenced Bow River IRONMKM KN\ METHODS 2.1 was loeated on the iI Bow (digital thermometer, ±0 °C) and conductivity (Oakton TDSTestr3, ±2%FS) were measured River within the study area each day during the study period Discharge information for the Bow River in at Calgary (Water Survey of Canada Station 05BH004) was obtained from the Forecasting Section of the Alberta Environment Water Sciences Branch FISH 2.3 CAPTURE AND ASSESSMENT Similar to the methods employed in 1999 (RLE 2000), fish sampling was conducted by members of The Alberta Environment, using two three-person crews and two jet-drive electrofishing boats Smith-Root SRI and a Roughneck Tunnelhull; each boat was equipped with a fixed-boom anode arrays The clectrofishcr units were yielding a total power output ranging from 3.5 to 5.0 A set at a These GPP frequency of 30 settings capturing large fish without inducing injuries Pulse widths of 60 a pulse width to and boats used were a 5.0 clectrofishcr unit and Hz and were determined Hz were RL&L two of 3.5 ms be the most efficient for not used as they may have resulted in a higher incidence of injury (Snyder 1995) Sampling within each section was conducted along both banks of the river To ensure optimum coverage, the boat operators manoeuvred the boats in a downstream direction In areas where islands were encountered (Sections and 3), sampling was conducted in the of the study area was sampled twice Lower Bow River channel where sufficient depth and better fish habitat existed Each section daily Fish Population Status Assessment - August 2000 Page Table B7 Date Raw data for aged fish captured in the Bow Section Species FL(mm) WT(g) 23 21 23 22 22 MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH MNWH 370 370 373 399 404 405 433 368 378 378 379 384 384 390 393 405 407 410 412 415 415 418 427 428 430 434 435 445 390 392 408 411 420 460 395 424 455 410 155 173 176 177 183 187 190 204 208 214 220 230 195 195 198 212 1085 850 965 1260 1280 1475 1590 995 925 1135 880 1165 950 1295 930 1110 1275 1400 1425 1440 1270 1370 1605 1360 1570 1520 1410 1685 985 1090 1340 1405 1370 1855 970 1565 1630 1235 50 85 75 60 80 90 105 125 120 135 145 190 105 110 105 145 Aug4D0 3 23 29 30 30 29 24 23 23 22 30 22 29 29 22 22 29 22 22 23 22 23 22 22 23 29 22 22 29 30 29 23 23 22 30 29 29 1 2 2 2 1 4 2 1 1 2 21 22 30 30 22 22 22 23 22 3 21 30 30 30 RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR Page of River, August 2000 Structure 3134 2983 3218 2833 2820 3132 SC SC sc sc sc sc M4 M27 so so so M31 Ml ** Age (yrs) 4 5 5 6 2862 3087 sc sc sc sc sc so sc so so sc sc so sc sc sc sc sc sc sc sc so sc sc M2 M25 M3 so so so 3499 3493 2805 sc sc sc R26 R9 R4 so so so 2671 3135 3492 2803 M26 2866 M10 M9 2859 2787 M14 2826 3086 3133 2835 3217 3088 2830 3140 M5 sc sc R18 R29 so so 3102 2878 2899 3124 2887 sc sc sc sc sc sc so so so R19 R25 R24 6 6 6 6 6 6 6 6 6 7 7 8 13 1 1 1 1 1 1 2 2 Table B7 Date Raw data for aged fish captured in the Bow Section Species FL (mm) WT(g) 30 21 21 29 22 30 23 23 RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR 226 232 235 239 240 244 245 257 289 295 165 30 Aug-00 30 22 30 22 29 22 21 30 22 30 30 22 30 21 23 21 29 29 22 23 22 23 23 29 22 21 22 21 22 22 21 21 22 29 29 21 21 22 22 1 29 22 22 22 23 21 2 190 170 150 210 205 220 225 295 410 385 450 345 500 770 775 605 535 645 590 705 810 785 840 635 830 860 925 1000 820 895 865 815 795 960 925 880 955 1245 935 1200 495 850 1015 900 855 1050 815 1010 1025 1135 1070 1205 1310 301 307 324 335 380 400 344 359 360 374 379 380 390 391 391 402 402 405 407 407 410 413 413 416 420 429 433 435 444 451 452 405 424 430 433 434 440 444 446 450 453 454 469 495 Page of River, August 2000 Sample # R22 R28 2990 2970 RIO 3093 R17 * Structure SO SO ** Age (yrs) 2 3489 SC SC SO sc so sc sc 3231 2 2 2 R27 so 2890 sc R23 so 3095 sc so sc sc so sc so so sc so R7 2784 2715 R21 2844 R20 R16 2809 R30 3034 3487 2981 R5 R1 3111 3145 3084 3485 3123 R3 2842 2979 3105 2779 3112 2841 2714 2713 2839 R13 R11 2975 3029 2872 2785 R2 2871 2811 2798 3144 2718 sc sc sc 2 3 3 3 3 so so sc sc sc sc sc so sc sc sc sc sc sc sc sc sc so so sc 3 3 3 3 3 3 3 4 4 sc sc sc so sc sc sc sc sc 4 4 4 Raw data Table B7 Y Date for aged ® 21 21 22 22 21 29 22 30 21 22 22 21 21 22 23 29 29 22 22 22 29 21 22 22 22 FL (mm) RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR RNTR 496 508 518 520 423 432 435 445 448 455 458 459 459 ^ 1 1 4 Indicate either Floy tag which were SC fin = scale; number clipped during the SO captured Species Aug-00 21 fish = scale and 461 465 465 465 470 483 502 505 511 530 535 523 539 in the Bow River, August 2000 Sample#^ 1450 1405 1570 2065 845 1040 1640 890 1045 940 1060 985 1200 1130 1295 1310 1130 1225 1040 1195 1385 1350 1675 1620 1630 1910 2721 2781 2724 3114 3085 2708 R8 2806 R15 3030 2863 2792 3032 2709 3113 3484 R12 R14 3098 2827 2837 R6 2776 2896 3361 2869 Structure ^ Age (yrs) SC SC sc sc sc sc so sc so sc sc sc sc sc sc sc so so sc sc sc so sc sc sc sc 4 5 5 5 5 5 5 5 5 5 6 or Alberta Environment identification tag (e.g., R12) Blanks indicate fish Bow River population estimate study otolith Page of 2000 August River, Bow the in captured trout rainbow and trout brown of weights and lengths fork Age-specific deviation B8 standard Table 2000 August River, Bow the in assessment population fish during recorded Examined*100 fish lnjuries)/Fish injured of No with Number S II 9- E Examined-Fish B9 Table (Fish Brown Trout 150-250 mm 251-388 FL mm > 388 FL mm FL n=34 km) Day / (fish CPUE Section Section Section Section km) / (fish CPUE n=9 km) / (fish CPUE _J^ Section Section Section Section km) / (fish CPUE n=120 n=109 All km) / Days Combined (fish CPUE Section Figure B1 Section Section Section Section Section Section Section Relative abundance, expressed as catch-per-unit-effort (CPUE), of brown trout size-classes the Bow River, August 2000 in Rainbow Trout 150-250 mm 251-380 FL mm FL > 380 mm FL n-7 Day km) / (fish CPUE Section Section Section Section n=15 Day km) / (fish CPUE n : Section Section Section Section n=14 n=44 Day km) / (fish CPUE Section Section Section Section Section Section Section Section n=12 Day km) / (fish CPUE I n=183 fZZZl .I Section I I Section Section Section n=209 All Days Combine km) / (fish CPUE Section Figure Section Section Section B2 Section Section Section Section Relative abundance, expressed as catch-per-unit-effort (CPUE), of rainbow trout size-classes in the Bow River, August 2000 Mountain Whitefish 150-199 mm FL 200-280 mm FL > 280 mm FL n-47 Day km) / (fish CPUE Section Section Section Section n=74 Day km) / (fish CPUE Section Section Section Section Day km) / (fish CPUE Day km) / (fish CPUE All Days Combined km) / (fish CPUE Figure B3 Relative abundance, expressed as catch-per-unit-effort (CPUE), of mountain whitefish size-classes in the Bow River, August 2000 (note changes in y-axis scales) APPENDIX C Population Estimate Data — CO CD a> LiJ o o o o o o o o o o o o o o o O o o CO M- o 0) CD O « LU JS Ui £1 o o o o o CM 00 CM 00 o o o o o o To o o o o o o o o o o o o o o o o 00 CM o o o o o o o o o o o o o o o o o o o 00 CM N CM ro o o o C5 o o o o o CO o o o o o o o o CO N CM C3) ro 11 CO o o o o o o o CM « o o o o o o o o o o o M- (O n CN $ C lU c 2000 o o o o o o o o o o o o o o o o o o o o (O o o o o CO CM 00 CNI o 00 CO o o o o o o o o o o o o o o o o CO CO o o o o o o o o o o o o o o o o o o o o o CO CD CM o o C3 o o o o o C3 o o o CM CO CO T o rv CO »- o o o o CO o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o T« CM Y- 00 CO r~ T~ CD T~ »- o o o o o o o o o o CO o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o CM Y- CO CM T- T- 00 CM T~ o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o CO o o o o Y- o o o o o o o o o o o CO CO CO o o o o o o o o o o o o o CO o »- CM CO o o o o o o o o o o o o o CM o o o o o o o o o o o o o o o o o o o Oi CO o o o o o o o o o o o o o o o o o o o o o o o o — ip N CM CD o CO o S CJ> o> (/) August c LU o o o o o C3 o m o o o o o C-) ( ) o o o o o o o o o o o C5 o o o o o o o o C) C3 C ) o o CO o CO o CO o o o o o C.J o o o o o o history T fish Y^ CTi River, 00 CO M- CO M- 00 00 CM O) CO encounter CO CO 00 CM o Mr same o> nl Bow the LU in C A size-classes w p 0> CO o o o o o o CO o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o given the of C3> o 00 n O T“ lO CM > > O E re presence exhibited o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o TT- o o o o o o run indicates that 5*'’ fish the of CO on number (0 i o o X o o o c o o LU o c Q_ a CO CM o o o o o o o o o o o o o -M- r~ of o o o o o o o O iS sportfish o o o o o o o o o o o o o o o> o o o o o o o o o o o o o o CO Oi o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o Mr oo 1^ CM CM o o o o o o o o o o o o o o o o o o o o 00 whereas recaptured the absence, cn CO and represent estimates s o o X o in o o o c o o LU o 01 ' population c CO CM o o o o o o o o CM o o o o o o o u £ E history 00 CM o o o o o o o c > p CM CO o o o o o o o o o o o o o Mr T— o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 00 CO CO o o o o o o o o o o o o o o o o o o o o 1^ Y^ CO o o o o o o o T— o o o o o o fish o o o o o o Y^ o o o o o o indicates configuration electrofishing CD CM CM o o o o o o o o o o o o o o CM o o o o o Mr CO CM runs; CM V- Mr o o o o o o o o o o o o o o o o o o o o o o o o o o M- M- Mr CM CM CO CO CO o o o o o o o o o o o o o o o o o o o o o o o o o o o o cy> CM r- CM Mr 2"'’ history the on encounter electrofishing CM o o o o o o o o captured each eight fish on beside based N run represents CO Mr italics 00 CO CO to CM m \ O) o o o o o o CO Mr C3i o o o o o o o o o o o o o o o o o o o o o o T— o o o o o o o o o o o o o o o o o o o o o c (0 '% o X o o o o c o o UJ o o o o o o o o c \ o 388/380^280 Species Brown trout Rainbow trout Mountain whitefish Year mm FL Total 95% Cl 95% fish/km Cl fish/km lower upper lower upper 1982 30 16 44 352 246 410 1983 61 128 693 469 916 1984 65 28 98 339 253 426 1985 111 60 157 378 263 493 1988 115 61 160 583 454 686 1990 52 23 82 503 309 698 1991 40 17 64 571 487 655 1992 69 11 139 528 375 681 1999 117 84 175 267 199 370 2000 202 103 427 660 397 1131 1982 91 65 117 165 121 208 1983 151 101 201 486 357 616 1984 98 62 133 1010 827 1192 1985 189 139 239 576 486 667 1988 217 177 258 539 451 625 1990 86 67 105 359 287 432 1991 121 92 151 292 224 361 1992 368 220 518 966 741 1192 1999 176 108 307 224 139 382 2000 1999 2000 223 155 82 297 337 229 649 681 491 853 1143 584 964 1273 1557 132 432 851 C c upper c C the 372 1162 200 404 C c 386 968 140 493 1293 1573 Cl in 95% 0) c C c c lower c c in Total 00 size-classes