BIOPHYSICAL EVALUATION OF 15 LLAKES ON THE NORTH COAST OF BRXTISH COLUMESIA
Prepared for the New Projects Unit Enhancement Operations Branch Department of Fisheries and Oceans Vancouver, B.C.
by T.L. Slaney AQUATIC RESOURCES LIMITED Vancouver, B.C.
March, 1988 The Department of Fisheries and Oceans is reviewing the potential for the rapid development of large, artificially sustained runs of high value salmon species for harvesting in discrete terminal fisheries. The object of this program is to provide benefits to commercial fishermen while diverting fishing pressure from weaker wild stocks. This report summarizes the findings of a program of physical limnology, water chemistry and fish sampling on 15 lakes. Most of the lakes are above barriers to returning anadromous fish, but they could serve either as enhancement water supplies or as rearing areas for juvenile salmonids. In addition, the report reviews the merits of the candidate systems on the basis of the in£ormation collected to date.
The candidate lakes included: Wyndham, Batchellor, Sylvia and Red Bluff Lakes on Grenville Channel; Whalen, Deer, Bear, Cougar, Butedale and Yule Lakes in the Princess Royal Area; Ingram and Ellerslie Lakes on Spiller Channel; Link Lake at Ocean Falls; Namu Lake on Fitz Hugh Sound; and Sandell Lake in Rivers Inlet. The lakes were sampled in February, June, August and December of 1987.
It was found that all of the lakes were highly oligotrophic and monomictic. The systems circulate all winter and there was no sign of oxygen depression at depth. Late summer oxygen concentrations at maximum sample depth ranged from 9.1 in Butedale lake to 11.8 mg/L in Whalen Lake. The waters were uniformly soft, with low pH values which ranged from 5.76 in Ingram Lake to 6.47 in Sandell Lake. The lakes were thus suitable for rearing fish but would have limited utility in incubation. Preliminary experiments were performed with salt-water injection and it was concluded that this technique may be useful in improving hatchery water quality. Zooplankton densities of 5.45 to 20.1 mg/m3 were found to be within the range of other similar lakes in coastal B.C. Fish densities were successfully estimated in only five of the systems, but ranged from 580 fish/ha in Link Lake to 7,160 fish/ha in Sylvia Lake.
The relative merits of the candidate lakes were assessed on the basis of: possible fishery con£ licts, availability of suitable donor stock, suitability of potential terminal fishery areas, presence of private sector interests, rearing potentials, freshwater quality, potential costs and potential predation. It was concluded that Link Lake offered the best opportunities due to its large size, low fish density and ample forage base as well as the potential for lower costs due to existing infrastructure and private sector interests in the area. Other top candidates included Namu Lake, and the Surf Inlet chain. ii
TABLE OF CONTENTS
Page Abstract i Table of Contents ii List of Appendices iii
INTRODUCTION
METHODS Logistics Climate Physical and chemical sampling Plankton Fish populations and their disease complements Outlet streams Background information Evaluation
RESULTS Climate Physical characteristics Water quality Phytoplankton Zooplankton Fish Outlets Ingram and Ellerslie background
ENHANCEMENT IMPLICATIONS Rearing potential Water 'quality Disease profiles Potential competition and predation
SUMMARY Recommendations for further study
ACKNOWLEDGEMENTS
LITERATURE CITED LIST OF APPENDICES
Volume I 1. Water quality data 2. Oxygen and temperature profiles 3. Thermograph records 4. Minnow trap catches 5. Fish health report.
Volume I1 4. Photo record
The appendices are under separate cover and are available from B.G. Shepherd, New Projects Unit, Enhancement Operations, Department of Fisheries and Oceans, Vancouver, B.C. Phytoplankton and zooplankton data were not included in the appendices. They are filed in the Limnology Lab at the DFO West Vancouver Laboratory. This report summarizes the results of a lake sampling program which was undertaken on behalf of the New Projects Unit, Salmonid Enhancement Program (SEP), Department of Fisheries and Oceans (DFO). SEP is investigating the potential for rapid development of large, entirely hatchery sustained runs of high value species, such as chinook and sockeye, for harvesting in discrete terminal fisheries. The object of this program is to provide benefits to commercial fishermen while diverting fishing pressure from weaker wild stocks.
The investigation of candidate sites began with a reconnaissance by SEP staff and the preparation of a report which ranked twelve lakes on the basis of existing information (Fedorenko 1987). The systems studied included: Van Inlet in the Queen Charlotte Islands; Batchellor, Red Bluff, Sylvia and Wyndham Lakes in Grenville Channel; Butedale, Bear, Cougar, Deer, Whalen and Yule Lakes in Princess Royal Channel; Link Lake at Ocean Falls; Namu Lake on Fitz Hugh Sound; and Sandell Lake near Good Hope on Rivers Inlet (Figure 1). All of the lakes were deemed to present some potential either as unused rearing capacity, gravity feed water supplies, or readily available infrastructure. During the course of the evaluation, a number of areas were identified where site specific physical and biological information would be required before the evaluation and decision making process could be completed.
To fill the data gaps, a lake sampling program was conducted between February and December, 1987. In the course of the program, the Van Inlet site was deferred and two additional sites were identified. Ingram and Ellerslie Lakes in the Spiller Inlet area were added to the later sampling sessions on the basis of their apparent rearing capacity.
The specific objectives of the lake sampling program were: 1. Compile existing water quality and temperature data . 2. Undertake basic limnology surveys including:
- temperature and dissolved oxygen profiles. - water quality profiles. - productivity estimates. - examine fall8 at outlet for potential to injure out-migrating juveniles. - sampling for potential predators and competitors.
It was further specified that program reporting should follow the format established by Fedorenko (1987) and that the new
information should be used to update the evaluation and ranking process initiated in that report.
An initial round of water samples was taken from the outlets of Sandell, Namu and Link Lakes by SEP staff during a January 1987 reconnaissance. Thereafter, four sampling sessions were planned for February, June, August and December, 1987. The February and December sessions focused primarily on water quality and physical conditions during the incubation period. The warm weather sessions were designed to examine some aspects of productivity and the disease, competitor and predator complements.
Logistics
The February, June and December sampling sessions were conducted from floatplanes based either in Prince Rupert or Bella Bella. At mid-lake stations, the aircraft drift was slowed by a drogue. An anchor was used outlet stations.
In August, the lakes were accessed by float plane and temporary camps were established. Sampling on these occasions was conducted from a 4 m inflatable boat.
Climate
Summaries for 1987 weather and 1951 - 1980 climatic normals were obtained for Bonilla Island at the northwest end of the study area and for McInnes Island, near Bella Bella (Figure I), from the DOE Atmospheric Environment Service.
Physical and Chemical Sampling
Two sampling stations were established in each lake (Figures 2 - 14) and additional temperature monitoring stations were placed in some of the outlets. The first station was placed near the lake outlets where the water depth was generally 10 - 15 m. These stations were intended to provide information on the water temperature and quality likely if incubation water were drawn from the lakes. A second station was placed in the major basin of each lake and samples taken here were intended to reflect conditions in the lake as a whole. Both stations were examined during the February session. In later sessions, only the mid-lake stations were sampled.
Sampling sessions included vertical temperature profiles with either a YSI model 33 (t0.5 'C) or a Hydro Lab Marine Thermometer with 50 m probe (t0.5 'C). Water samples were taken with a Van Dorn bottle. Samples from surface, 10 m and 80 m (or near bottom in shallow lakes) were placed in PVC containers for lab analysis of Figure 2 WYNDHAM LAKE
@ - SAMPLING STATIONS
KILOMETERS
RED BLUFF LAKE
@ - SAMPLING STATIONS @ - MINNOW TRAP GROUP - GILLNET SITE - SOUNDING TRANSECT
KILOMETERS Figure 6 WHALEN LAKE - SAMPLING STATION
@ - MINNOW TRAP GROUP I9 I9 - GILLNET SITE
000 - SOUNDING TRANSECT
("<
KILOMETERS
Figure 10 INGRAM LAKE
@ - SAMPLING STATION
LAKE
0 I 2 KILOMETERS
\ Braden River
Figure 12 LINK LAKE
@ - SAMPLING STATION Q - MINNOW TRAP GROUPS - GILLNET SlTE - - SOUNDING TRANSECTS * - MILL SlTE A - TOWN SlTE
nutrients and metals. Two samples were taken from each of the surface, 10, 20 and 80 m depths for dissolved oxygen determination by Winkler titration (t0.2 mg/L). Two litre samples from the surface and 80 m depths were placed in PVC buckets for pH and conductivity measurements using a Fisher model 119 portable pH meter (20.05 pH units) and a YSI model 51A TSC meter (t2 umhos/cm). Oxygen samples were titrated each afternoon and no samples were stored for more than eight hours (Strickland and Parsons 1972).
Metals, nutrients and residues from the February sampling sessions were analysed by the EPS/DFO Cypress Creek Lab and Quanta Trace Laboratories Inc. (EPS 1979). Samples from the later sessions were analyzed at the MOEP Environmental Laboratory at U.B.C. (MOEP 1976). The parameters examined are summarized in Table 1 along with the criteria used in subsequent evaluations. At the Cypress Creek Lab, all of the metals were presented as total values. Samples analysed at the MOEP lab were treated slightly differently and potassium and sodium were expressed as dissolved quantities.
During the June and August sessions, an acid washed, double distilled, de-ionized water rinsed screw capped test tube was filled with 100 ml of water from the lake surface, covered with clean aluminium foil and stored near 4°C for later analysis of total phosphorous. These samples were shipped to the DFO West Vancouver Laboratory where they were analysed by staff of the Lake Enrichment Program using the method outlined by Stephens and Brandstaetter (1983).
At the conclusion of the February round of sampling, it was apparent that although the lakes offered abundant rearing habitat, none of the study lakes had waters of high enough pH and hardness to support intensive (hatchery) fish culture. A series of experiments was therefore initiated to investigate the possibility of using small amounts of sea-water to raise the pH, conductivity, hardness and calcium levels of the freshwater supplies. During the June and August sampling sessions at Butedale, samples were taken of the surface sea-water and of Butedale Creek. The pH and conductivity of both samples were noted. Two additional freshwater samples were taken and 5 - 20 mL of sea-water was added. The conductivity and pH of these mixtures were noted and all four samples were preserved and shipped to the MOEP Lab for analysis as described previously.
Temperatures at the outlets of Butedale, Cougar and Link lakes were monitored with Ryan thermographs (20.5 "C). The Butedale thermograph was placed in a sink in one of the residences during the February survey. This building was unfortunately destroyed by fire during the spring of 1987. In August, a replacement thermograph was placed under boulder cover in the tail race approximately 80 m below the power house. Table 1 SUMMARY OF VATER QUALITY PAUMETERS ANAL'Y'SED AND THEIR ASSOCIATED LIMITS Parameters Detection Recommended Toxic Analysed* Limits Values * * Values Alkalinity >I5 Ammonia <0.005 (totalM.03 Chloride .5 470 ,400 Conductivity (umhos) 150 - XKKI Hardness >20 Nitrite 4.005 d.015 02 pH (re1 units 1 6.5 - 8.5 6. >9 Phosphate (0.05 Residue - Filterable 70-400 Residue - Non filt. <3.0/ a*** Silica
At Ocean Falls, the Link Lake thermograph was placed in a valve chamber within the pulp mill filter house.
Plankton
Phytoplankton and zooplankton were sampled during the June and August sessions. Phytoplankton samples from the surface of each lake were stored in opaque 250 mL bottles with 1 mL of Lugol's solution. Vertical zooplankton hauls were made from a depth of 50 m with a 0.5 m diameter, 100 um UNESCO-SCOR net. Zooplankton samples were preserved in a sucrose-formalin solution per Haney and Hall (1973).
Phytoplankton and zooplankton samples were identified, enumerated and sized by staff of the DFO Lake Enrichment Program as described by Nidle et al. (1984).
Fish Populations and Disease Complements
Fish populations in some of the lakes were sampled during the August session. Because of time and budget restraints, only those lakes which were either recommended by Fedorenko (1987) or easily accessed were sampled for fish. Work therefore concentrated on Namu, Link and Butedale Lakes. Additional lakes, including the Yule, Surf Inlet, Red Bluff, Sylvia and Sandell systems, were included as time and logistics permitted. One or more gillnet sets were made in each of the these lakes. The nets were of graduated panel construction and contained 5, 8 m x 3 m panels which were graduated from 2.5 cm to 12 cm stretch mesh. They were set perpendicular to the shore with the small mesh at the shallow end. Sets were made in the afternoon and retrieved in the early morning. Captured fish were identified, counted, packed in individual plastic bags and placed on ice for shipment within 36 hours to the DFO Diagnostics Lab in Nanaimo.
Near-shore fishes were also sampled by Gee minnow trap. Standard sets of 30 traps were made in groups of 10 traps per Hyatt et al. (1985). Where possible, the traps were set in early afternoon and retrieved in 3 - 6 hr. On some occasions, logistics dictated that the traps were set in early evening and retrieved the next morning. Captured sticklebacks were preserved in 50% ethanol. After one week, they were drained and transferred to 70% ethanol. A Furuno FM-22 200 kHz sounder with 100 watts power output and an added time varied gain circuit was used to make estimates of limnetic fish populations. The sounder was mounted in the inflatable boat and transects were sampled across each of the major basins of the study lakes. During the evening prior to sounding, lights were placed at each end of the transects. The transects were then sounded between 2200 and 0200 hours with the boat running at a constant speed. The sounding tapes were then interpreted and extrapolated to estimates of whole lake populations by staff of the Lake Enrichment Program's Productivity Assessment Unit per Hyatt et al. (1985).
Disease and parasites in the salmonids collected by gillnet were examined by the DFO Fish Health and Parasitology Unit at the Pacific Biological Station. All fish were checked for gross external and internal abnormalities. To test for bacterial pathogens, kidney material from each fish was plated onto Tryptic Soy Agar and a Gram stain of kidney material was evaluated. Up to a maximum of 15 fish per sample, were checked for protozoan parasites in the internal organs. With the exception of coho, all fish were assayed in lots of five for the presence of IHN or IPN virus.
Outlet Streams
All of the outlet streams were inspected and photographed from the air, particularly during the February and December sampling sessions when the leaves were off the trees. During late summer low water, the outlets of the Whalen, Surf Inlet, Butedale, Ellerslie, Link and Namu systems were walked and examined in greater detail. Mean gradients of the outlet streams were determined from the lake elevation (Fedorenko 1987) and 1:50,000 topogaphic maps.
Background Information
Ingram and Ellerslie Lakes were added to the study after Fedorenko (1987) had completed her survey of the available data on candidate systems. As a result, information was missing on the following topics:
- Possible fishery conflicts - Availability of suitable donor stocks - Suitability of terminal fishing sites - Presence of private sector interests - Site construction and operating costs
To fill some of these gaps, local DFO personnel were contacted. In addition, some .extrapolations were made from Fedorenko (1987). The resulting summaries are in no way exhaustive but were deemed sufficient for evaluation purposes.
The evaluation process was designed to complement the earlier work of Fedorenko (1987). A ranking system was established for each category describing the study systems and the systems were rated from 1 (best) to 10 (worst) on the basis of their rankings. The three lakes of the Surf Inlet chain were considered as one unit. An overall rating for each project was obtained by calculating its mean rating over the range of categories. All of the categories in the rating and evaluation process were weighted equally.
RESULTS
CLIMATE
Rainfall and temperature generally followed the patterns of the long term normals at Bonilla and McInnes Islands during 1987 (Figure 15). The distribution of rainfall at both stations was slightly unusual with approximately half the normal rainfall recorded during the months of July and August and heavier rainfalls in November and December.
The winter of 1986/87 was quite mild and monthly mean temperatures for January and February were well above normals at both stations. At Bonilla Island, the January 1987 mean temperature was 2.5 "C above normal. During the late winter and spring, the mean temperatures declined relative to the normals and by June there was essentially no difference. Total precipitation was near the 1951 - 1980 average from January through June. The July rainfall was well below average as was the precipitation in October. November and December rainfalls were higher than normal such that by the end of the year, the total precipitation of 2,018 mm was 96% of the long term normal at this station.
The mean temperatures at McInnes Island followed a trend similar to that at Bonilla Island, although the data for November and December were not available. Rainfall at this station was well above normal; particularly in April, June and November. As a result, the total rainfall for the year was 3,187 mm, which is 25% more than the long term average.
The stations Bonilla Point and McInnes Island are located near the north and south ends of the study area. In addition, they are the only stations within the area for which both long term records and 1987 data are available. They do, however, differ somewhat from most of the study lakes in that, except for Namu Lake, all of the study systems are at higher elevations and are Figure 15 Monthly mean temperature and total precipitahon at Bonilla and McInnes Islands, 1987 (Atmospheric Environment Service file station records, AES 1 9 82)
Bonilla Island
15 600 h h 0 El w w8 10 400 g
C .r( a C Ll (d Q, .Cd Q 9 5 200 'B Q, Q, w L PI a L 0 O E Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mc Innes Island
600 h 8 0 w w8 10 400
C .Cd Q L 2 .d Q, Q
4 5 200 0"Q, Q, w aL a C 0 0 E Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
o - 1987 Temperature - 1987 Precipitation
- 1951 - 1980 Normal Temperature - 1951 - 1980 Normal Precipitation
! separated from the open ocean by at least one range of mountains. The study systems are thus likely to be slightly warmer in summer, cooler in winter and generally have higher total precipitation. At the now inactive Ocean Falls climate station, annual total precipitation averaged 4,386 mm compared to only 2,558 mm at McInnes Island during the period 1951 - 1980 (AES 1982). Mean July temperature was 15.6 "C which was 1.9 'C warmer than McInnes Island and the mean January temperature of 0.2 "C was 2.7 "C colder.
PHYSICAL CHARAmERISITCS
The study lakes can all be characterized as coastal warm monomictic and oligotrophic. They were strongly stratified in summer and circulate at temperatures near 4 "C through most of the winter (Figures 16 - 30).
In February, the water columns of all of the lakes were relatively homogeneous. At mid-lake, temperatures were near 4 "C down to the maximum sampling depth of 83 m. Oxygen concentrations were all greater than 11 mg/L which is near saturation at this temperature.
By June, there was evidence of a developing thermocline as temperatures in the upper 10 m increased to 10 - 12 "C. With this heating, there was some decrease in dissolved oxygen in the epilimnion. However, it remained near saturation in all of the lakes and there was no change at depth.
When the lakes were sampled again in early August, the epilimnion was well developed at all stations. In the southern lakes, which were sampled first, surface temperatures ranged from 18.6 - 22 "C. Rainfall during the latter part of the sampling period resulted in cooler temperatures at the surface of the northern lakes. Generally orthograde 0, profiles in all of the study lakes provided evidence of their oligotrophic status. Oxygen saturations were >80% at the deepest stations in all of the lakes except Sylvia, Yule and Namu Lakes which were extrapolated to 78%, 76% and 73% saturation respectively. The 80 m depth in Butedale Lake was slightly lower at 65%.
The lakes were last sampled at the beginning of December. At that time there was still some evidence of the summer stratification. However, the surface water had cooled considerably and it was evident that the lakes would soon be mixing.
Water temperatures at the outlets of the Surf, Butedale and Link systems are shown in Figures 31 and 32 and in Table 2, all of which indicate peak water temperatures in early August and steady declines thereafter. In general, the temperatures reflected the nature of the outlets. At Butedale where water is drawn from the lake surface and temperatures were taken below the power house, water temperature peaked at 20.6 "C. This was 4 "C higher than r
Figure 16 Oxygen and temperature profiles at Wyndham Lake, Stahon 2, 1987
February 13 June 10
0 5 10 15 20 0 5 10 15 20 0
20 h 8 30 V C 40 40 C e 50 0 60 60 70 70 80 80
~ugust1 6 December 2
0 5 10 15 20 0 5 10 15 20 0
h 8 30 V 40 B I 8 50 0 50 0 CI 60 60 70 70 80 80 o
0 - Temperature (C) rn
Figure 17
Oxygen and temperature profiles at Sylv~aLake, Stahon 2, 1987
February 14 June 12 0 5 I0 I5 20 0 5 10 15 20 0
20 0 h El 30 V C 40 0 Y e 50 0 la 60 70 70 80 80
August 16 December 2 0 5 10 15 20 0 5 10 15 20 0
h 8 30 w C 40 40 Y a 50 o 50 91 n 60 60 70 70 80 80
C Figure 18
Oxygen and temperature profiles at Batchellor Lake, Stahon 2, 1987
February 13 June 10 0 5 10 15 20 0 5 10 15 20 0
.- El 40502030 0 w ~-!- s 4 504 0 fa 60 60:-"- 70 70 o 80 80
August 16 December 2 0 5 10 15 20 0 5 10 15 20 0 - El wefa4 5060340 0 ::pep-50460iP4!- 0 0 70 70 80 80 0
0 - Temperature (C) Figure 19
Oxygen and temperature profiles at Red Bluff Lake, Stabon 2, 1987
June 12 0 5 10 15 20 0
h 30 w8 G 40 Q 50 0 al c? 60 70 80 •
DQCQ~~Q~3 0 5 10 15 20 0 -.-1 1 h . 8 w 5 40 e 50 c? 60 70 80 0
- Temperature (C)
A Figure 2 0
Temperature and oxygen profiles at Whalen Lake, Stahon 2, 1887
February 11 June 13 0 5 10 15 20 0 5 10 15 20 0
'i- nVs84 4205030'i- 0 0 450 0 oo fl 60 7-60 70 70 80 80
August 13 December 3 0 5 10 15 20 0 5 10 15 20 -3-
n 30 30 wa s 40 40 4 50 50 n 60 60 70 70 80 80 Figure 2 1
Oxygen and temperature profiles at Deer Lake, Stabon 2, 1987
February 1 0 June 13 0 5 10 15 20 0 5 10 15 20
20 n 30 30 wa 5 40 40 8 50 0 50 0 fa 60 60 70 70 80
December 4 0 5 10 15 20 0
Not n #ampled in August 30 wa 40 5 I a 50 0 Q) CI 60 70 80 0
L Figure 22 Oxygen and temperature profiles at Bear Lake, Station 2, 1987
February 1 0 JUM 14 0 5 10 15 20 0 5 10 15 20 0
20 n 8 30 30 V C 40 0 Y 4 50 a 60 60 70 70 80 80
August 18 December 4 0 5 10 15 20 0 5 10 15 20 0 9- -*-
20 n 8 30 o 30 V 40 o 40 G I 6 50 0. @ 50 fa 60 60 70 70 80 80 I J
Figure 2 3
Oxygen and temperature profiles at Cougar Lake, Station 2, 1987 I
Fekrcxary 1 1 Jane 14 0 5 10 15 20 0 5 10 15 20
20 .- 8 30 o .4 4 40 40 0 8 50 50 0 (3 60 60 70 70 e 80
August 18 Decerxber 4 0 5 10 15 20 0 5 10 15 20
20 .? i3 30 30 kd B 40 40 a 50 0 50 0 Q f=3 60 70 70 80 80 Figure 25
Oxygen and temperature profiles at Yule Lake, Stahon 2, 1987
February 15 0 5 10 15 20 0 -*- / /
30 40
60 70 80
December 6
o - Temperature (C) Figure 2 7
Oxygen and temperature profiles at Ellerslie Lake, Stahon 2, 1987
June 1 S 0 5 I0 15 20 0 0
6 8 Not sampled 30 V in February C 40 C Q 50 0 Q) fa 60 70 80
December 8 0 0 5 10 15 20 0 0
h8 2 lo-'4!- 0 30 w C 4 0 Y Q 50 Q) 6a 6 0 70 80 o Figure 24
Oxygen and temperature profiles at Butedale Lake, Stabon 2, 1967
February 1 5 June 15 0 5 10 15 20 0 5 10 15 20 o -*- 98-
20 n 30 wa 40 40 A" 2 SO 0 fr 60 60 70 70 80 80
August 10 December 6 0 5 10 15 20 0 5 10 15 20 0
20 n 30 0 30 wa 6 40 0 40 0 4 50 0 50 0 CI 60 60 70 70 80 80
. Figure 26
Oxygen and temperature profiles at Ingram Lake, Stabon 2, 1987
June 16 0 5 10 15 20 0
- Not earnpled a in 30 V February 5 40 Q 5 0 0 Q) 60 70 80
Auguet 8 December 8 0 5 10 15 20 0 5 10 15 20
h a 30 V 40 40 5 I Q 50 50 0. Q) 6a 60 60 70 70 80 80
! w
Figure 2 8
Oxygen and temperature profiles at Link Lake, Stabon 2, 1987
Februery 16 June 17 0 5 10 15 20 0 5 10 15 20 0
20 h 30 30 w8 G 40 3 50 0 ~c 60 60 70 70 80 . 80 .
August b December 7 0 5 10 15 20 0 5 10 15 20
.h 30 w8 6 40 40 a 50 al Cc 60 60 70 70 80 80
L -
Figure 2 9
Oxygen and temperature profiles at Namu Lake, Stabon 2, 1987
February 17 June 18 0 5 10 15 20 0 5 10 15 20 0
20 n 8 30 30 w 40 40 s 50 4 50 cl 60 60 70 70 80 80
August 5 December 9 0 5 10 15 20 0 5 10 15 20 0 B-
20 n 30 30 w8 5 40 40 4 50 50 fa 60 60 70 70 80 80
* Figure 30
Oxygen and temperature profiles at Sandell Lake, Sahon 2, 1987
February 17 June 18 0 5 10 15 20 0 5 10 15 20 0 - 20 8 30 30 V 5 40 4 0 Q 50 Q) a 60 60 70 70 80 0 80
August b 0 5 10 15 20 0
- Not sampled 8 30 in December V 5 4 0 Q 50 aQ) 60 70 80 0 L
Figure 3 1
Daily maximum and minimum temperatures at Surf River Penstock and Butedale Power House, 1987
Surf River
20 -
h V 1 5 V 6
Y 10- 0 k 6
-# flk z6 5 I-
0 1 01 30 28 29 27 26 24 23 21 19 18 16 15 Jan Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Butedale Power House
20 -
h ---0 15.p QI
c. lo*, r0 8, e 5 c 0 + 01 30 28 29 27 26 24 23 21 19 18 16 15 Jan Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
L h
Figure 32
daily maxlmum and minimum water temperatures at Ocean Falls filter house, 1987
20 -
n wv 15- 01 LI Y
b 01
012 5.) I- ---r 0 * 01 30 28 29 27 26 24 23 21 19 18 16 15 Jan Jan Feb Mar Apr May Jun Jul Auq Sep Oct Nov Dec Table 2 Summary of mesn and extreme mter temperatures (C) at lake outlets, 1987 Surf Inlet Butedale Ocean Palls Notes January man 2.2a a StartJan.14 Max 3.5 Min 2.0
February Mean b c 2.1 b Installed Feb 11 : Max 2.2 meter stalled. Min 1.9 c Installed Peb 15: March Mean 2.4 building burnt do Max 3.3 Min 1.9
April Mean 3.4 b b meter jammed on Max 3.5 April 2 Min 32
May Mean Max I Min
June Mean 9.4 d 72 c c Re-start June 14 I Max 12.0 8.O d Re-start June 17 Min 8 .O 6.6
J~Y Mean 11.7 Max 152 Min 9 .O
August Mean 15.0 18.3 e 12.8 e New meter Max 16.6 20.6 14.5 August 10 Min 12.5 16.8 11.0
September Hean 15.1 15.7 12.6 Max 16.7 18.6 152 Min 8.9 12.8 11.1
October Mesn 11.3 11.6 10.9 Mar 12.0 13.7 12.1 Blin 7.5 9.8 9 .O
November Mean 9.4 8.4 8.5 Max 10.7 3.8 9.9 Win 8.3 7.2 7.1 the Surf Inlet or Ocean Falls outlets, both of which are drawn from the bottom of the dams.
Interestingly, the greatest die1 temperature range and the most precipitous temperature drop in September came not from the surface intake at Butedale, but from the the penstock at the base of the Surf River dam. Daily temperatures there varied over a range of 1 - 2 "C. The cause of these changes was not immediately clear. It was unlikely to be caused by heating within the pipe as flows were about 0.5 m3/sec. The only other possibility would be insolation along the cliffs on the north side of the reservoir near the intake. In early September, there was a dramatic event: the daily minimum fell from 12.5 - 7.5 "C over two days. For the following week, the daily minimums were near 10 "C.
WATER QUALITY
All of the systems examined during this program were below recommended fish culture levels for alkalinity, conductivity, hardness, pH, filterable residues, turbidity and calcium (Table 3, Sigma 1984). In addition, several of the lakes had aluminium, copper, cadmium, lead or zinc levels which were higher than recommended. It should be noted that the following paragraphs discuss the water quality of the study lakes in terms of intensive (hatchery) fish culture. Fish rearing at large in the lakes would be at much lower densities and the water quality requirements would therefore be less rigorous.
In Wyndham Lake, pH averaged 5.9 and ranged from 5.7 to 6.1, with no relation to depth or season. Alkalinity 1.6 mg/L) was the lowest of the study lakes and hardness averaged 1.75 mg/L (1.3 - 3.3 mg/L), well below the recommended minimum of 20 mg&. Filterable residues were very low in all of the samples. The February 13 sample from 10 m at station 1 had levels of non- filterable residues which were excessive for incubation use although acceptable for rearing. Aluminium equaled or exceeded the recommended level of 0.1 mg/L in five of the 12 samples taken from this lake. Phosphorous concentrations from Wyndham Lake were the highest of the 15 study systems, largely as a result of high values during the February survey. In June and August, when more precise measurements were taken, Wyndham Lake phosphorous concentrations were the lowest examined.
The pH (6.21) and hardness (2.22 mg/L) of Sylvia Lake were slightly higher than those in Wyndham Lake, although still well below recommended levels. Aluminium levels were high in all of the surface samples taken at station 2 but at all other stations and depths, it was present at less than 0.1 mg/L. Total phosphorous concentrations of 0.09 mg/L at station 1 (2 m) and 0.12 mg/L <*t station 2 (surface) reported in February appear to be aberrat~ons as all other phosphorous samples were in the range 0.0013 - Table 5 Sumaary* of water quality analysl Lake Wyndlmcn Lk Sylvia Lk Batchellor Lk Red Bluff Lk Whelen Lk M.of 8awl 15 15 15 15 15 Alkalinity Ammonia Chloride I 1.1 1.4 1.3 1.4 1.1 Conductivity {mnbdcm) field 6.0 4.0 8.4 5.3 Conductivity {umhs/ctd lab 1 9.0 8.7 10.8 8.9 Dissold - 02 ppm 11.1 10.9 11.3 11.1 Hard- 2.22 1.84 2.1 7 2.39 Nitrite Nitrate 0.03 0.03 0.03 0.03 pH (rel. u) - Field pH {rel. u) - Lab Phosphate Residue - Filterable Residue - Non filt. Silica Sulphate Turbidity {FTU) A1 -Alaatim As -Arsenic Ba- Barimn
1 Zn -Zim I 0.002 0.012 0.006 - Xean of all values greater than the detection knits. (4unless mtcd) - Values exceed* reconvaended levels (Table 1) are uderlined. - Individual sample resalts are listed in Apperdix 1. - Table continues overleaf Table 3 {contiaued) Sununary* of water quality analysis Lake Deer Lk Bear Lk Cougar Lk Butedale Lk Yule Lk 12 15 12 15 15 Alkalinity Aavnotda Chloride 1.5 1.4 1.2 1.2 Cductivity (&/cd field 5.6 6.0 10.0 6.4 Conductivity (umhodcm) lab 10.7 9-7 8.3 8.6 Dissolved - 02 ppm 10.9 10.8 10.5 10.6 Hardfws 2.93 2.1 0 1.63 2.16 Ptrite 0.006 Witrste 0.03 0.03 0.1 0 0.04 pH (rel. u) - Field 6.30 6.05 5.82 6.22 pH (rel. u) - Lab 6.0 5.9 5.5 5.8 Phosphate 1- 0.009 0.003 Residue - Filterable 13 11 7 8 Residue - bnfilt. Silica 1 .O 1 .O 0.8 0.9 Sulphate 1 1 1 1 Turbidity (FTa 0.50 0.54 1.57 1.41 A1 -Alrrmimm 0.1 2 0.12 0.1 2 0.1 0 0.08 As -Ar8enic 0.00 Ba- Bariutn 0.002 0.002 0.002 0.002
Zn -2im 1 0.002 0.003 0.003 0.005 0.013 * - neam of 811 retuw @e%terthan tk detection limits. (4ad- mted) - Values exceeding recommended levels {Table 1) are underlined. - Individual sample resalts are listed in Appendix 1. - Table continues overleaf Table 3 {continad) Smamrp* of water quality analysis Lake Ingram Lk Ellerslie Lk Link Lk Hemu Lk Sardell Lk I&. of rraatples 9 9 15 15 12 Alkalimty 2.3 2.2 2.5 2.7 4.1 Amnotlie 0.006 0.01 0 Chloride 0.8 2.2 1.1 Conductivity {umhoslcm) field 10.0 4.5 10.5 6.9 Corrductiviip {umhos/cm) lab 8.2 7.9 10.6 14.4 12.1 Dissol~- 02 ppm 10.3 10.5 10.9 10.6 10.7 Hard- 2.07 2.38 2.88 3.75 3.89 fitrite Nitrate 0.03 0.04 0.06 pH (rel. u) - Field 5.76 6.04 6.30 6.1 8 6.47 pH (rel. u) - lab 5.7 5.7 6.0 5.9 6.2 Phosphate 0.003 0.003 Residae - Filterable 9 10 8 11 10 Besidue - Non filt . 11 Silica 1.3 1.3 1.2 1.4 0.9 Srrlplmte 1 1 1 1 1 Turbidity o'm 0.50 0.47 1.63 1.86 1.95 A1 -Almtilum 0.1 7 0.12 0.07 0.22 0.12 As -Arsenic 0.00 Ba- Barium 0.005 0.002 0.002 Ca-Calciam 0.49 0.59 0.91 0.96 1.25 Cd -Cadmiam 0.0002 0.0005 Co -Cobalt
- Fe -Iron 0.1 27 0.042 0.088 0.245 0.1 31 Hg -Hercur7 0.00007 0.00008 0.00008 K -Potaeaium 0.12 0.1 0 0.1 5 0.16 0.1 2 Hg -Ha@esimn 0.20 0.22 0.14 0.29 0.1 7 Mn -Har@nese 0.006 0.01 7 0.006 Ho -Holybd~ Ha -Mican 1.2 0.8 0.7 1.5 0.7 Ni -Nickel 0.00 0.00 0.00 P -Pbospborws 0.0043 0.0033 0.0041 0.0077 0.0040 Pb -Lead 0.004 0.007 0.01 9 0.004 0.009 Sb -Antiammy SQ -kletriam Si -Silicon 0.5 0.7 0.5 , ir -2ktium 0.005 0.004 0.004 0.000 0.002 0.002 ~;--T;?timam 0.000 [Zn -Zinc 0.01 0 0.006 0.008 0.010 0.006 * - Hean of all values gr~atertlmn the btection limits. ~ttt#'L adem noted) - Values exceeding recomnendd levels (Table 1) are underlirred. - Idividuai sanple results are listed inAppendix 1. 0.0039 mg/L or <0.05 mg/L depending on the analytical technique used. A zinc concentration of 0.017 mg/L was reported from the surface sample at station 1 in February. However, this appears to be due to sample contamination as all other samples were well within recommended limits and averaged 0.012 mg/L.
In Batchellor Lake, the alkalinity (1.8 mg/L), conductivity (4 umhos/cm), hardness (1.84 mg/L), pH (5.84) and calcium (0.32 mg/L) concentrations were among the lowest of the systems studied (Table 3). Aluminium (0.12 mg/L) exceeded the recommended 0.1 mg/l in all but one of the samples taken. Copper concentration (average 0.002 mg/L) was high in one of the surface samples and in two of the three samples taken from 80 m at station 2.
Red Bluff Lake pH averaged 6.23 and hardness 2.17 mg/L; well below the recommended levels. The 'system's alkalinity (2.2 mg/L) was in the mid range of the systems studied Aluminium (average 0.07 mg/L) was present in detectable concentrations in all but one of the samples however only one sample contained enough to be of concern. Phosphorous concentrations were the lowest of the 15 lakes at 0.0025 mg/L.
Whalen Lake had high concentrations of aluminium in all but three of the samples (average 0.11 mg/L) and excessive copper (0.002 mg/L) in three of the samples. The June and August phosphorous levels of 0.0035 mg/l and 0.0029 mg/L were higher than most of the study lakes. The pH ranged from 5.9 - 6.2 (average 6.04) and hardness was only 2.1 - 2.7 mg/L (average 2.39 mg/L).
The alkalinity (2.4 mg/L), conductivity (12.9 umhos/cm), hardness 3.1 mg/L), pH (6.24) and calcium (0.80 mg/L) concentrations of the Deer Lake samples were among the highest of the study lakes while metals concentration, particularly copper (0.001 mg/L) and lead (0.003 mg/L), were among the lowest. On the other hand, phosphorous concentrations were also very low, averaging 0.003 mg/L, which was one of the lowest
The waters of Bear Lake were generally similar to those of Deer Lake which is to be expected, as the two are only separated by a shallow sill. There were some concerns that the lake has been adversely affected by leachates from the defunct Surf Inlet gold mine located on the Paradise Creek tributary. The creek carries the run-off from several tailings piles and shaft drains and had a lower pH of 5.65 on December 4, 1987. Because of these concerns, samples were taken from all three of the lake basins. There was little sign of elevated metals levels in Bear lake. Most of the concentrations were similar to those of Deer Lake. Although detectable levels of mercury are always of concern, and the mercury levels in Bear Lake were higher than the other lakes, they were still well below the recommended maximum of 0.0002 mg/L (Table 1). Cougar Lake, which is at the downstream end of the Surf Inlet chain, was much lower in hardness (2.1 mg/L) and pH (6.05) and somewhat lower conductivity (6.0 umhos/cm) than Deer and Bear Lakes.
The pH and hardness of Butedale Lake were the lowest of the systems studied, averaging 5.81 and 1.63 mg/L respectively. Alkalinity (2.0 mg/L) and calcium (0.46 mg/L) were also among the lowest studied. The Butedale Lake samples also had relatively high metals concentrations. Lead averaged 0.006 mg/L, the highest of the study lakes. Copper averaged 0.00188 mg/L, which is below the recommended maximum of 0.002 mg/L (Table 1) although the limit was actually exceeded in six of 11 samples analysed at the time of writing. Cadmium averaged 0.00033 mg/L which is near the recommended limit in soft water (Table 1).
The waters of Yule Lake were not quite as low in pH and hardness as those of Butedale Lake. However, they ranked in the lower third of the lakes examined (Table 3). Like Butedale Lake, Yule Lake had high metals concentrations including lead (0.004 mg/L), and copper (0.003 mg/L). Cadmium (0.0014 mg/l) was the highest of the study lakes.
Samples from Ingram Lake had mean concentrations of 0.16 mg/L aluminium, 0.005 mg/L copper and 0.004 mg/L lead which are above the recommended limits for fish culture (Table 1). In addition, the mean chromium concentration (0.04 mg/L) equaled the recommended maximum. These metals levels are of particular concern as the pH and hardness of the system were quite low (Table 3).
The hardness and pH of Ellerslie Lake were lower than recommended for fish culture (Table 1) but near the median of the fifteen study lakes. Mean concentrations of aluminium (0.12 mg/L), copper (0.002 mg/L) and lead (0.005 mg/L) exceeded recommended levels for soft water.
The pH of Link Lake (6.3) was among the highest of the study systems. It was also one of the few systems in which lead (0.019 mg/L) and aluminum (0.07 mg/L) were both within the recommended levels. None-the-less, its low alkalinity (2.5 mg/L), hardness (2.88 mg/L), conductivity (10.6 umhos/cm), and calcium (0.91 mg/L) were similar to the other lakes sampled.
Namu Lake ranked in the top third of the study lakes in terms of alkalinity, calcium, hardness and pH (Table 3) although it was still well below recommended levels for fish culture (Table 1). The mean lead concentration, 0.004 mg/L, far exceeded recommended levels. Aluminium and copper levels were also above recommended levels In several of the samples. Among the fifteen study systems, Sandell Lake had the highest mean alkalinity (2.4 mg/L), hardness (3.89 mg/L), pH (6.47) and calcium (1.25 mg/L). Unfortunately, the system's metals levels were also high with aluminium (0.117 mg/L), copper (0.002 mg/L) and lead (0.09 mg/L) all well above recommended limits for fish culture (Table 1).
Sea-water Mixes Sea-water (SW) mixing experiments conducted at Butedale on June 15 were intended to produce three solutions with conductivities near 100 umhos/cm. The main objective of the experiments was to increase hardness, pH and buffering capacity. Conductivity was used as an indicator during the mixing process as it permits rapid and relatively accurate observations under field conditions. pH would have been a more desirable indicator, but would have made the mixing process very difficult as the pH meter takes up to 20 minutes to stabilize in soft water at pH <6.5. The 100 umhos/cm level was selected initially as a minimum level likely to produce useful results for fish culture.
The addition of 0.4 - 0.45% SW at 12,800 umhos/cm resulted in mixes of 90 - 114 umhos/cm (Table 4). At 114 umhos/cm, pH was 6.19, hardness was 14 mg/L and calcium was 1.16 mg/L. All of which were near the recommended minimums (Table 1). Alkalinity remained low at 2.4 mg/L. SW addition increased levels of lead and aluminium which were already at or near recommended maximums. However, the toxicity of these metals decreases with increasing hardness and pH (Sigma 1983). Copper concentrations were unusually high in the Residence water samples which was unexplained as the plumbing appeared to be iron. Copper levels in the mixed samples were all much lower although slightly above the recommended levels at 0.003 mg/L.
In ~ugust,a second series of mixes was made with the object of further raising the conductivity, hardness and pH. On this occasion, the conductivity of the sea surface (22,000 umhos/cm) was higher than it had been during the June samples. Increasing the conductivity to 157 umhos/cm required only a 0.35% SW addition and resulted in a solution with a pH of 6.5 which would be acceptable for hatchery operation. Hardness (17.7 mg/L), calcium (1.53 mg/L) alkalinity (2.9 mg/L) were still below recommended levels. In this set of samples, sodium levels increased to 25.6 mg/L although the aluminium values remained relatively low (0.07 mg/L) and the copper concentrations were just over the recommended limit at 0.002 mg/L. Unfortunately, due to problems in preservation, only a few parameters of the ocean surface sample could be analysed
The results of the June and August mixes were plotted in Figure 33. The conductivity ratio (12,800/22,000) was used to adjust the June dilutions for the differences in salinity on the two days. As some of the important parameters were still below recommended levels at 0.0035% SW addition, values for increased SW Table 4 Redts of Freshwater/Saltwater mixes at Butedale, B.C. 15-Jun-87 15-Jun-87 15-Jun-87 15-Jun-87 15-Jun-87 Parameters* Residence 0.40% SW' 0.42% SW' 0.45% SW' banSfc Alkalinity 1.9 2.9 2.6 2.4 (u-8 l d - field 5 90 95 114 12,800 (umtms / cm) - lab 6 129 129 156 Dissolved - 02 ppn 10.4 Dissolwd - 02 W Sat 98.2 Dis8olwd Gas Total 1 05.4 Dissolved Nitrogen 107.39 Hardnew 1.3 12.1 12.3 14 Nitrite (0.005 (0.005 (0.005 (0.005 Nitrate (0.02 (0.02 (0.02 (0.02 pH (rei. u) - Field pH (rel. u) - Lab Silica Sulpbete < 1 5.2 4.9 5.9 Temperature (C) 13 14 14.1 11 Turbidity (FTU) 1 1.1 1 1 A1 -Aluminium 0.12 0.1 7 0.1 3 Ca-Calcium Cd -Cadmium
I 1 mg/l anless stated Values QxGeQdingreconrreended litnits are underlined. Table contimes awxleaf. Table 4 contimed hltsof Freshwster/Saltwater mixes at Butdale, B.C. 1 9-Aug-87 09-Anq-87 09-Aug-87 09-Aug-8; Parmeters* Dock (FW W) 0.24% SW 0.35% SW (bcoan Sfc Alkalinity (umh/ cd - field (umhos / cd- lab DissolQed - 02 ppm Dissolved - 02 1Sat Dissolved Gw Total Dissolwd Nitrogen Hardness Nitrite Nitrate pH {rel. a) - Field pH (rel. u) - Lab Silica Sulpbte Temperature (C) Turbidity {FTW A1 -AlWnium Ca -Calcium Cd -Cadmium Co -Cobalt Cr -Chromium Cu -Copper Fe -Iron K -Pota88itna Hg -Hagzwsium Mn -Manganese Ho -Molybdenum Na -Sodium Ni -Nickel P -bporm Pb -Lead v -vaaebitrm 1Zn -Zinc
* 41unless stated Valaes exceeding recomrrendd limits are drlirred. Figure 33 Effects of saltwater addikons on selected freshwater parameters at Butedale, B.C.
-June 15, 1987 o - August 9, 1987 I
Conductlvlty Hardness
200 1 20- (C, 0 0 u 150.b u, 15.b \ . V 9 10.b 50
0- 0- 02 4 0.0 0.1 0.2 0.3 0.4 0.0 0.1 0.2 0.3 0.4 Saltwater addition (%) Saltwater addition (93)
pH (field) Sodium
0 30 7 0 n ** 0 0 V . % 6.0: E 9 .3 lo-,
5.5 00 I 0.0 0.1 0.2 0.3 0 4 0.0 0.1 0.2 0.3 0.4 Saltwater addition (93) Saltwater addition (7%)
Alkalinity Calcium
0 0 V 1.0 Q. , 3E U
0.0 0.0 01 0.2 03 04 0.0 0.1 0.2 0.3 0 4 Saltwater addition (%) Saltwater addition (%)
! were calculated. In the absence of information about the ocean surface sample, regression and extrapolation from the mix results were used to predict results for increased SW concentrations. Sodium concentrations increased at 72 mg/L/%SW addition (r2 = 0.98) and would equal the upper recommended limit of 50 mg/L at 0.007% SW addition. This appears to be the maximum safe SW addition. An operational limit would probably be 0.006% SW addition.
Using the same regression and extrapolation process, it was calculated that at 0.006% SW addition, conductivity would be 240 umhos/cm, hardness would be 29 mg/L, pH would be 6.7 and sodium would be 44 mg/L. Calcium and alkalinity would still be below the recommended levels at 2.4 mg/L and 2.8 mg/L respectively. The regression on alkalinity results was not significant (r2 = 0.59) however, values for the ocean surface were available and the results were extrapolated by dilution. Values for aluminium,. copper and lead were not calculated but would probably be slightly above the recommended limits.
PHYTOPLANKTON
Phytoplankton samples were collected during the June and August surveys. However, staff shortages at the West Vancouver Lab delayed their analysis past the report production date (K. Shortreed, DFO pers. comm.). ZOOPLANKTON
In the following sections, total biomass estimates are compared as dry values while those of individual taxa are expressed as wet values. This is because zooplankton samples were split in the lab. One half of the sample was dried, weighed and expressed as (mg/m3, dry). The second half was enumerated and sampled using the DFO Caliper s stem (Sprules et al. 1980). This results in abundance (animals/mY ) and blomass (mg/m3, wet) estimates for each zooplankton taxon. The discussion focuses on groups which are common sockeye forage such as Bosmina and Daphnia as well as potentla1 competitors such as Chaoborus.
Wyndham Lake had very high concentrations of Chaoborus in both June and August samples (Table 5) although they declined frc~m 98,000/m3 to 19,500/m3 between the two samples. Other major changes included a shift in numerical dominance from Diaptomus to Bosrnln Total zooplankton biomass in the Sylvia Lake samples increased slightly from 6.5 to 9.0 mg/m3 (dry) between the June and Aucjust samples (Table 5). None-the-less, total biomass was about the median of the study systems. The zooplankton composlt 1 c)n Table 5 Sarmtary of Jrw zooplankton h1s(August hauls on follorimg page) Total z#p. ~r#,.&?rQY &phi* &p%* Lake Replicate Biomass Biomass Biocrrass Ilean Size {dry. dm3) (wetmg/m3) (wet, tng/m3) ~md) Wyndham 1 7.3 93,087 0.1 18 0.602 2 9.7 103,462 0.000 0.000 mean 8.5 98,274 0.059 0.301 Sylvia 1 4.9 0 0.236 1.1 20 2 8.1 0 0.522 0.844 mean 6.5 0 0.379 0.982 Batchellor 1 7.8 0 32.1 69 0.934 2 7.9 0 28.404 0.936 mean 7.9 0 30.286 0.935 Red Bluff 1 4.6 0 3.094 0.690 2 3.8 0 2.499 0.777 mean 4.2 0 2.796 0.733 W'halen 1 4.8 10,681 7.788 0.646 2 4.4 18.1 65 5.003 0.609 man 4.6 14,423 6.396 0.628 Deer 1 8.8 35.523 5.035 0.692 2 6.4 4.914 3.090 0.702 Bear 1 18.8 0 2.559 0.721 2 14.0 0 2.663 0.667 Congar 1 4.0 906 0.140 0.749 2 3.7 0 0.649 1.114 mean 9.3 6.891 2.356 0.774 Butedale 1 6.6 5.025 36.905 0.945 2 6.8 4 8 34.890 1.087 marl 6.7 2.536 35.897 1 .016 Yule 1 4.0 0 9.280 0.938 2 4.8 0 2.467 0.706 mean 4.4 0 5.873 0.822 Ellerslie 1 6.2 26,038 4.349 0.866 2 12.5 50.535 5.71 9 0.830 mean 9.4 38,286 5.034 0.848 Ins= 1 5.6 1.783 2.31 7 0.71 5 2 8.2 5.295 2.498 0.674 an 6.9 3.539 2.408 0.694 Link 1 3.7 0 9.963 1.009 2 3.1 0 3.657 0.795 nwan 3.4 0 6.81 0 0.902 Wsma 1 8.9 34 3 4.499 0.640 2 16.3 1,926 11.900 0.635 nwrn 12.6 1,134 8.1 99 0.638 Sandell 1 8.3 80,688 136.300 1.025 2 10.1 16,292 105.970 0.971 mean 9.2 48,490 121.1 35 0.998 Table 5 {contimed) SumMIy of Auw-lankton hauls Total Zoop. Ckbuurm &pihi* &phi* Lake Replicate Biomrrss Biottm88 Biontass ~eanSite (dry, mg/m3) (wet,mg/m3) (wet, dm3) {mn) Wyndhstn 1 6.4 10.714 0.000 0.000 2 4.5 28.435 0.000 0.000 man 5.5 19.575 0.000 0.000 Sylvia 1 9.6 0 0.61 8 0.760 2 8.4 0 0.322 0.696 man 9.0 0 0.470 0.728 Batchellor 1 9.4 38,672 34.068 1 .041 2 6.8 14,389 15.108 0.969 me8n 8.1 26.530 24.588 1.005 Red Bluff 1 11.0 0 1 .1 85 0.634 2 10.2 0 4.401 0.754 me8n 10.6 0 2.793 0.694 Wen 1 9.8 1,162 6.754 0.737 2 10.2 5,061 6.163 0.71 8 mean 10.0 3,112 6.459 0.727 Bear 1 9.2 1,471 7.391 0.754 2 8.2 0 6.744 0.807 COU~W 1 6.0 0 0.877 0.631 2 12.0 540 0.504 0.896 me8n 9.0 270 0.691 0.763 Batedale 1 10.8 2,223 29.400 1.080 2 10.2 2,437 22.1 38 0.999 man 10.5 2,330 25.769 1.039 IWm 1 7.0 177 14.266 0.81 6 2 mrd ll~e8n 7.0 177 14.266 0.81 6 Yale 1 5.2 0 1.013 0.735 2 6.0 0 1.085 0.697 mean 5.6 0 1.049 0.716 Ellerslie 1 5.9 1,273 28.543 0.923 2 8.4 3,591 19.671 0.889 ueaa 7.2 2,4 3 2 24.1 07 0.906 Link 1 18.0 1 37.291 0.943 2 22.2 6,805 32.614 0.91 7 cmwl 20.1 3,4 0 3 34.953 0.930 httw 1 14.0 15,603 3.347 0.794 2 23.8 12,418 2.558 0.713 18.9 14,010 2.953 0.754 Sandell 1 4.9 76,239 44.926 1.057 2 4.7 116,380 60.147 1.030 m~8z~ 4.8 96,310 52.536 1.043 Figure 34 Relative abundance (animals/m3) of major zooplankton groups in Wyndham and Sylvia ~akes,1Y87 Jlme Allgl-rst Wyndham Lake Sylvia Lake Di@hm~me U ICalanoM -mind fli~tmm ~X~phniB Nauplii :.:::::... . . :.:.:.:.:.:.:. HD~D-~UM Rotdfo. Q.vlc1p CA~~QPW I remained relatively unchanged over the summer except for an increase in the number of nauplii present in the August sample. None of the samples from Sylvia Lake contained Chaoborus. The Batchellor Lake samples illustrate the problems of typifying lakes from a small number of plankton samples. In the June samples, there were no Chaoborus (Table 5, Figure 35). However, the August samples from Batchellor Lake had the second highest concentrations (26,500/m3) among the study lakes. Other changes over the summer included a decline in the relative abundance of nauplii and Diaptomus, and an increase in Bosmina and Daphnia. Total plankton biomass in samples from Red Bluff Lake increased dramatically from 4.2 mg/mYdry) in June to 10.6 mg/m3(dry) in August (Table 5). During this period, the zooplankton composition remained relatively constant, aside from an increase in the relative abundance of Bosmina (Figure 35) Neither sample set from this lake contained Chaoborus. In Whalen Lake, the total zooplankton biomass increased from 4.6 mg/m3(dry) in June to 10.0 mg/m3(dry) in August (Table 5). During this period, the Daphnia concentration did not change and remained near 6.4 mg/m3(wet). Principal causes of the increased total biomass were changes in Bosmina from 203 to 482 /m3 and in Diaphanasoma from 4.36 to 282 mg/m3(wet). Chaoborus concentrations were high (3.1 - 14.0 g/m3(wet) in both samples from this station. Deer Lake was only sampled in June. At that time, the numerically dominant group were the various nauplii, followed by Bosmina (1,171/m3) (Figure 36). Chaoborus abundance was moderate at 4.8/m3 (Table 5). Mean zooplankton biomass in the Bear Lake samples increased from 5.9 to 8.7 mg/m3(dry) but remained near the lower end of the range of the study lakes (Table 5) Principal composition changes between June and August included increases in Diaphanasoma, Daphnia and Diaptomus as well as a major decrease in the relative abundance of Bosmina (Figure 37). Cougar Lake is separated from Bear Lake by the Surf River. Since impoundment in 1918, the river is no more than a shallow sill. June zooplankton composition in the Cougar Lake samples was very similar to those from Bear Lake (Figure 37). Total biomass was also similar at 3.8 mg/m3(dry) in June and 8.7 mg/m3 in August (Table 5). The August composition was quite different from that of the Bear Lake samples, as Bosmina numbers remained high and large numbers of rotif ers appeared. Zooplankton biomass in Butedale Lake samples increased from 6.7 mg/m3(dry) in June to 10.5 mg/m3(dry) in August. Principal composition changes over the period included a decrease in nauplii _. Figure 35 Relative abundance (animals/m 3)of major zooplankton groups in Batxhellor and Red Bluff Lakes, 1987 June August Batchellor Lake Red Bluff Lake I fl~~h6?.~~~ma U I Calsnoid mmina fli~tomw Pqhnia Nauplii ::::::: ..:.:.:...... Holop&~m R~tdtoria ~~?10~ LAmhr.m Figure 36 Relative abundance (animals /m 3) of ma1 or zooplankton groups in Whalen and Deer ~akes,1987 .Jme August 'h1sn Leks Deer lake Not Sampled in Arxgust ~,i@hmmmzt U ICalanoid mmina fli~romur -13nizt Nauplii ...... ::::::: HOID~&~UM ~oraforia L~.W~OJC chrnbruf r Figure 37 Relative abundance (animals/ms) of major zooplankton groups in Bear and Cougar Lakes, 1 9 23 7 June August Bear Lake Corzgar Lskc Di&pBamwrna U I Calanoid &f2221iza Diqt0mw Aphnia Nauplii ...... :.:.:.:.:.:.: Hulup&i~m a Ru?&?u~i& c~~:lo~v a CnLchr~r P and increases in Bosmina and rotifers (Figure 38). Mean Chaoborus densities were constant at 2,300 - 2,500 mg/m3(wet) and ranked in the mid-range of the study lakes. The Yule Lake zooplankton samples were dominated by Bosmina and nauplii in both June and August samples (Figure 37). Total biomass was relatively low at 4.4 - 7.0 mg/m3(dry) in both sample sets. Chaoborus densities were amongst the lowest sampled at 0 mg/m3(wet) in June and 177 mg/m3(wet) in August. Daphnia concentration increased from a mean of 5.87 mg/m3(wet) in June to 14.3 (mg/m3(wet) in August although its abundance relative to the population as a whole decreased slightly (Figure 38). Zooplankton biomass in Ingram Lake was quite low in both June (6.9 mg/m3(dry) and August (7.0 mg/m3(dry) (Table 5). In June, the most abundant groups included Diaptomus and Bosmina, both of which were near 25% of the total population. Nauplii, Daphnia, Cyclops, Holopedium and an unidentified calanoid were less numerous, each representing 10 - 15% of the total (Figure 38). In August, Diaphanasoma increased from 22 mg/m3(wet) to 405 mg/m3(wet) and Daphnia, increased from ll/m3 to 440/m3. Almost half of the organisms present in the June zooplankton samples from Ellerslie Lake were nauplii of one type or another (Figure 39). The next most numerous groups were Diaptomus and an unidentified calanoid. In the August sample, there were far fewer nauplii and the unidentified calanoid was not apparent. In contrast , Daphnia and Diaphanasoma increased Zooplankton biomass in Ellerslie Lake was about average relative to the other lakes studies with 6.9 mg/m3(dry) in June and 7.0 mg/m3(dry) in August. Chaoborus densities were also in the mid range at 3,500 mg/m3(wet) in June and 2,432 mg/m3(wet) in August (Table 5). Zooplankton biomass in the Link Lake samples ranked as the lowest of the study lakes in June at 3.4 mg/m3(dry) and as the highest in August at 20.1 mg/m3(dry) (Table 5). In the June samples, slightly over 50% of the organisms present were nauplii of various types, while Diaptomus were the next most numerous (Figure 40). In the August samples, these two groups together composed less than 25% of the total as Holopedium and Daphnia were numerically dominant. Cyclops formed the most numerous groups in both June and August samples from Namu lake (Figure 40). Bosmina and Holopedium which were also present in large numbers in June declined in August when large numbers of Nauplii were seen. Total zooplankton biomass was among the highest of the lakes samples at 12.6 mg/mYdry) in June and 18.9 mg/m3(dry) in August (Table 5). At the Sandell Lake station, the August biomass of 4.8 mg/m3(dry) was the lowest of the study lakes and much lower than the 9.2 mg/m3(dry) sampled in June (Table 5). Diaptomus densities in Figure 36 Relahve abundance (animals/m 3) of major zooplankton groups in Bukdale and Yule Lakes, 1987 June August Eutedale Lake Yule Lake Diwhmmma TJ I Calanoid l&?xrnlna mn Diwl~~ Dq~hnla Nauplii ...... :.:.:: ...... XDI~&I.~LIIU 60180ria Gyvtop Cimbrw Figure 3~3 Relative abundance (animals/m 3 of major zooplankton groups in Ingram and Ellerslie ~akes,1987 .Jl-ine Algust Ingram Lake Ellerslie Lske fl.bpAanmma U I Calanoid ~mina 11 ~iwr~mw mbnia Nauplii 0;;::::: ...... HoSopefi~m AoIatoNR ~-t^iop .5^Amkrrw r Figure 40 Relative abundance (animals/m 3 1 of major zooplankton groups in Link and Namu ~akes.1967 June Augllst Link Lake N.mu Lake ~~r'~Ammrnd U ICalmoid mmim WJ J!!*~O~LLT LkpAnia Nauplii ...... :.:.:.: .:.:.:. ~o~o~ium a ~utaturi~ Cp?Ibp a Lbdoh-rur b these samples declined from 1,700/m3 in June to 156/m3 in August. Daphnia concentrations also declined from 1,700 to 787/m3. However, with the drop in total population, they became numerically dominant (Figure 41). Chaoborus densities rose from 14.1m3 to 23.1/m3 over the summer. Overall, zooplankton biomass in samples from the study lakes (Table 5) ranged from 3.4 - 20.1 mg/m3(dry) which is similar to the non-glacial, coastal monomictic lakes of British Columbia which were examined by Rankin and Ashton (1980). Gillnetting and Minnow Trapping Gillnets and minnow traps were set in some of the study lakes with the primary objectives of collecting specimens for disease analysis and to determine the presence of resident species. Minnow traps were set in Namu, Link, Ellerslie, Butedale, Whalen, Red Bluff, Sylvia and Bear Lakes (Table 6). Sticklebacks were collected in all except Whalen Lake. In addition, cottids were collected from Ellerslie, Butedale, Red Bluff, Sylvia and Bear Lakes. Whalen Lake was the only system where the trap sets did not produce either sticklebacks or cottids. Trap catches there consisted of Dolly Varden char and trout. The lack of sticklebacks in Whalen Lake may be related to the substrate which contained large numbers of boulders and was quite exposed. Unfortunately, program logistics did not permit a standardized soak time and many of the minnow trap sets were made overnight rather than during daylight as recommended by Hyatt et al. (1984). In the absence of a standard catch per unit effort, the trap catches best serve as a rough indication of species present in the near-shore areas. Gillnet sets were made in nine of the 15 study lakes and the results are summarized in Table 7. The gillnet sets were somewhat more consistent than the minnow trapping as most of the sets were left overnight. The exception to this was in Namu Lake, where net checks during the evening revealed that excessive numbers of adult sockeye were being caught and gillnetting had to be stopped. None-the-less, there was a great deal of variation in the effectiveness of the gillnet sets resulting from variations in near-shore habitat. Cutthroat trout were collected in all gillnet sets except those in Yule and Whalen Lakes. Kokanee were present in catches from Red Bluff, Sylvia and Bear Lakes, while Dolly Varden were only found in the catches from Namu, Butedale Yule and Whalen Lakes. Cottids were collected in Link and Bear Lakes. Figl~.re4 1 Relative abundance (animals/m 3) of major zoopla.nkton grol-~ps in Sandell Lake, 1987 June August I 1riw~3anm~a U ICalanoid ~mmina mJ ~niqtomw LkpnRla Nauplii .:.:.:. ::::::: MO~~UM @ ~.m~zori~ L).'~"ldzpr a Ch.%obrm L Soundings Transects were sounded in Sylvia, Red Bluff, Whalen, Bear, Cougar Butedale, Link and Namu Lakes (Figures 2 - 14). The soundings from Butedale and Namu Lakes revealed very high concentrations of Chaoborus and could not be interpreted for fish densities. The results from the other lakes are summarized in Table 8. Fish densities ranged from 580 fish/ha in Link Lake to 7,160 fish/ha in Sylvia Lake. The ultra-oligotrophic coastal systems examined as enhancement candidates by Hyatt and Stockner (1985) ranged from 75 to 5600 fish/ha. Species Composition The available information on fish species present in the study lakes is summarized in Table 9. No data were available for Wyndham or Ingram Lakes; however, cutthrout trout have been recorded in all of the other study systems. Kokanee, sticklebacks and Dolly Varden are also present in most of the systems. Given the preliminary nature of the sampling program, it is reasonable to suspect that all four species are found throughout the study lakes. Disease and Parasites The results of the fish health check performed by DFO Diagnostic Services are summarized in Table 10. In general, the sample sizes were too small to permit a detailed characterization of each lake population. None-the-less, some trends are evident. No viruses were found in any of the samples despite assays for IHN and IPN. Of the fifteen parasites looked for, Myxobolus arcticus was most common and was found in the brains of all lake samples except those from Link Lake. Diphyllobothrium was also common being found in samples from Yule, Butedale, Sylvia and Red Bluff Lakes. The only bacteria found which are known to be pathogenic to salmonids were Renibacterium salmoninarum and Yersinia ruckeri. These are the pathogens responsible for bacterial kidney disease (BKD) and enteric redmouth disease (ERM), respectively. One fish in each of the samples from Sandell, Namu and Yule Lakes was R. salmoninarum positive, but there were no overt signs of BKD-like lesions in any fish. Y. ruckeri was found in nine of the 19 Dolly Varden sampled from Whalen Lake and in one of the 18 cutthroat from Sylvia Lake. OUTLETS Stella Creek flows out of Wyndham Lake and drops over a chute- like fall approximately 5 m in height into a small (10 ha) lake. From there, the creek descends over a series of falls and cascades to Grenville Channel, a distance of 650 m. The mean gradient of the creek is 13%. There is a fall of 15 m approximately half way down the hill and a second of 7 m near the ocean. The system was observed from the air only. Table 8 Summary of sounding rfansects Lake Transect Targets Mean targets Fish lm2 /m2 /ha Bear D-C 0.166 E-F 0.501 0.334 3,300 A-B 0.176 0.176 1,760 Link A-B 0 .620 C-D 0.#0 E-F 0.066 H-G 0.045 0.058 Red Bluff 8-A 0.071 C-D 0.091 E-F 0.055 0.072 Sylvia B-A 0.246 C-D 0.386 E-F 0.739 Ii-G 1.493 0.716 7,160 Whalen A-8 0.244 D-C 0.101 F-E 0.192 0.179 1,790 Table 10 Summary of diseases and paras:'-- - -- Lake Species Sample Bacteria %us Parasites Size BKD ERM ABCDEF G Sylvia kokmee 49 19/19 cutthroat 18 1/18 Red Blut'f cutthroat 15 kokanee 1 Beat cutthroat 61 kokanee 11 Butedale cutthroat 16 Dally v. 4 1Yule Dolly V. 9 1/3 9 /9 l~ink cutthroat 13 13/13 1 Namu Dolly V. 3 1/3 2/2 1/2 113 cutthroat 4 2 /4 coho 4 2 /4 114 infections observed/subsample size PARASITES df~.To&Iw mAIir:uf in brain HFI'I&~ inurinarybladder Afm.dum in kidney Chlumm,~1.um in gall bladder PBiIo~erna D.!iG)n.*Io&rium L330.d~wh in swim bladder (list includes only those parasites found in at least one sample.) Sylvia Lake discharges over a narrow sill. At station 1, approximately 40 m from the discharge (Figure 3), the depth was 50 m. Below the lake, the outlet creek flows 30 m and drops over a 5 m fall into an outlet lake of 47 ha. Below this small lake, Sylvia Creek descends in a steady series of cascades. The system has a mean gradient of 3%. The outlet area was ground truthed, however, the remainder of the creek was viewed from the air only. At the outlet of Batchellor Lake, there is an extensive debris jam. Many of the logs support growths of grasses and small trees indicating that the jam seldom moves. Below the lake, Batchellor Creek descends with a mean gradient of 6% for 1.6 km. There are two falls of 3 m in an otherwise steady cascade descent. There is an extensive area of shallows at the outlet of Red Bluff Lake which contains an accumulation of logs and debris. This shallow area tapers into Red Bluff Creek which flows 450 m to Grenville Channel with a mean gradient of 7%. There is one particularly steep set of cascades just above Grenville Channel. Whalen Lake has an elevation of 118 m and discharges into Whale Channel over a distance of 1 km. The mean gradient is 12%. There are no significant plunge pools and the flow tumbles over bedrock for most of its length. A shoal holds a large debris jam in the lake about 100 m from the outlet. Most of the material appears to be derived from logging operations on the lake which took place during the 70's. This suggests that freshets or surges must happen at infrequent intervals and have removed earlier, natural debris. Deer, Bear and Cougar Lakes discharge into Surf Inlet over a 26 rn dam. From there, the Surf River drops over a cascade-like fall of 7 m into Surf Inlet. There is a lip on the spillway which causes most of the water column to fall clear of the dam. However, the plunge pool is quite shallow. At the north end of the dam there is a 1.3 m diameter pipe which leads from the bottom of the dam and spills into a small creek. This pipe was at one time the power house penstock. Scavenging operations after the mlne closure included removal of the pipeline. At present the plpe flows at approximately 20% of capacity. There is probably a partially closed valve somewhere in the dam structure but time did not permit further investigation. Butedale Lake discharges from an elevation of 99 m into Princess Royal Channel. The creek falls and cascades over bedrock for most its 500 m length with a mean slope of 20%. A pipeline intake has been constructed 100 m south of the natural outlet. The intake 1s a concrete structure and includes trash racks, screens and stop logs. A small channel has been excavated from the lake to the intake. At the lake's natural outlet, a concrete sill has been constructed. At low water levels, this sill directs all of the flow to the intake and the natural creek remains dry. Leaks in the pipeline flow down a narrow chute into which the power house also discharges. This flow joins the natural outlet channel just above the ocean. Yule Lake lies at an elevation of 108 m above Swanson Bay on Princess Royal Channel. It discharges through a creek which is 820 m in length and has a mean gradient of 13%. There are several drops of <5 m in height and some low weirs which remain from the pulp mill operation. Approximately halfway down, the flow splits around a bedrock outcrop. Both of the resulting channels then fall over a drop of approximately 15 m. There appears to be a well developed plunge pool below these falls. Falls at the outlet of Ellerslie Lake discharge directly into Ellerslie Lagoon which lies 14 km from the head of Spiller Inlet. The falls are in two parts totaling 21 m in height. The upper falls are <10 m high and drop into a small bedrock pool. At high water levels, a second outlet discharges down a narrow chute into the same pool. The lower falls are approximately 12 m high and drop into the lagoon well clear of the rock. At the outlet of the lagoon there is a shallow sill. Water flow over the sill is quite turbulent on ebb tides. Ingram Lake lies near the head of Spiller Inlet. It is separated from the inlet by a 400 m long creek. The creek forms a series of cascades and has a mean grade of approximately 10%. At Ocean Falls, the level of Link Lake has been raised to approximately 50 m by the construction of a 23 m dam at the top of the natural falls. Water falling from the dam's spillway drops to a small, turbulent plunge pool. Below this pool, the turbulence continues as the flow drops over the natural falls which contain numerous rock out-crops. In addition to the spillway, the dam can discharge through turbines and through a process water pipeline which leads to the mill site. During 1987, only one of the four turbines was in operation. Some water was flowing through the process pipeline but the amount was unmeasured. Namu Lake lies at an elevation of 15 m and is connected to Namu Harbour on Fitz Hugh Sound by a 0.5 km creek. The creek descends at a 3% gradient over a substrate of boulder and cobble and is easily negotiated by salmonids passing in either direction. The Sandell River flows 2.7 km from Sandell Lake and discharges into Rivers Inlet at Good Hope. The river has a mean gradient of 5% however, this is a misleading figure as there are two small lakes along the route and the remainder of the river is largely formed of falls and cascades. The largest of the falls lies 0.5 km below Sandell Lake. It descends 24 m in an extremely turbulent flow which is broken by numerous rock outcroppings. INGRAM AND ELLERSLIE BACKGROUND The Ingram and Ellerslie systems were added to the program after Fedorenko (1987) had completed a review of the information available at that time. The following section is intended to complete the data set for the later additions so that subsequent evaluations can be made on the basis of similar information for all 15 candidate systems. Ingram Lake is located in DFO Statistical Area 8, approximately 50 km north of Bella Bella and flows into the north end of Spiller Inlet. The discharge from Ellerslie Lake enters the inlet 16 km further south. In examining the fisheries and cultural background of the area, the two lakes can generally be considered as one unit. Potential Fishery Conflicts B. Bailey (DFO Bella Bella) reports that there are late summer net fisheries for pink and chum in Area 7, Seaforth Channel, which could conflict with terminal fisheries if they were late in the season. Other potential conflicts include: a planned Area 8 net fishery for chinook in Fitz Hugh, Fisher, Dean and Burke Channels, a July sockeye fishery in Area 8 Fitz Hugh/Fisher area, and the summer troll fisheries in Areas 6 - 11 (DFO 1986, Fedorenko 1987). These problems appear less severe than those faced by either Ocean Falls or the Butedale Group and the lakes were rated at 5. Availability of Donor Stocks Most of the commercially significant salmon stocks in DFO Statistical Area 7 are composed of either chum or pink salmon and there are only small numbers of sockeye and coho. In Spiller Channel, which lies just to the south of the candidate lakes, there is one significant sockeye stock (Tankeah River, mean escapement 1,500) and two coho stocks (combined mean escapement 300). Given the small size of the local stocks, it would be necessary to look further afield. Potential donor systems are summarized in Table 11 where it can be seen that there are good sockeye, coho and chinook donor stocks available but they are all further away than would normally be desirable (Fedorenko and Shepherd 1986). Suitability of Terminal Fishing Sites Spiller Channel is an existing DFO sub-area which is actively managed for chum and pink salmon (DFO 1986). Spiller Inlet comprises the northern half of this sub-unit and is 25 km long and varying in width from 2.5 km at the south end to near 1 km at the northern end. The depths are not known as the area is uncharted. However, the surrounding topography suggests that it is reasonably deep. There may be some traffic associated with the proposed logging program in Ellerslie Lake, but at the moment the area is little used. A discrete terminal fishery could be confined Table 11 Sutnmary of potential domu stocks for proje ts at In&? m and Ellerglie Lakes :S~ECIES~ ( Mean beans Esc, adproximity 1 Maritu Fisbry Access to ! system (~sca~ernentl48 of taxget I + 10 krn (Orientatiot Conflicts I Broodstock SOCKEYE 1 LoweIrdet ( 6,100 1 153 I 210 1 85 Heavy Prob. reasorable 01 [ 51 37 6.2 fair Heavy ProR. reasonable 11 01 I51 47 7.8 fair lioderate Difficult 111 [ 51 11 01 141 [ 31 11 01 33 5.5 good Beila Coolal 41,300 55 130 5 5 Light Good Atnarko R. 11 I [ 61 [?I [ 21 (11 I11 1 20 3.3 1 good Kimsqrxit R. 16,.400 55 145 55 Moderate Float Plane 11 I 161 [?I [ 21 [ 51 [ 91 32 5.3 good Koeye R. 4,000 20 105 85 Light B'o road [ 81 [ 91 [?I 141 [ 11 [ 91 40 6.7 fair Namt R. 2,600 35 8 5 9 5 Light small comnit y [ 91 [ 81 [ 81 [41 [I1 [ 81 38 6.3 fair COHO m-4 Belia Coolal 22,100 2 8 130 55 Moderate Good I AttwrkoR. . [I] [ 81 [ 91 [ 21 [ 51 [ 11 26 4.3 good Dean R. 3.400 34 135 55 Moderate Limited [ 91 [ 81 [ 91 [ 21 [ 51 [ 91 42 7.0 fair Kimsquit R. 3.1 00 8 145 55 Heavy No road [ 91 01 [ 91 [ 21 [I01 [ 91 49 8.2 poor Koeye R. 3.300 13 105 8 5 Heavy No road 191 [I01 [ 91 [dl 11 01 [ 91 51 8.5 poor Kwatna R. 6.300 4 2 120 70 Heavy Limit. road I61 [ 71 191 I41 11 01 [ 71 43 7.2 fair Mwtin R. 2,000 3 3 6 0 0 Heavy Frob, reasonable [I01 [ 81 [ 61 Ill [I 01 [ 31 38 6.3 fair CHINO OK Belia Cooial 1 3,300 5 3 130 55 Moderate Good, Hatchery Atiwrko R. [I] [ 61 [ 91 [21 [ 51 [I] 24 4.0 good Dean R. 3,100 [ 61 135 55 Moderate local logging roads [ 81 [ 81 [ 91 [Zl [ 51 [ 41 41 6.8 fair Ovevril rating calculated from the total iuunber of 'good' donors (5) plus half the 'fair' stocks (81 = 8 (Fedorenko 1 9871 to the head of the inlet, although the fishing industry may have fish quality concerns. Private Sector Interests At present, there are no aquaculture leases within the Spiller Inlet area although there have been some expressions of interest and preliminary surveys (B. Bailey, DFO Bella Bella , pers comm.). A proposal for 'A-frame' logging of the Ellerslie Lake foreshore is under review by the B.C. Forest Service and DFO. A decision on this proposal will be made after site inspections this fall. Availability of Sea Pen Sites There are areas of significant herring spawn along the west side of Spiller Channel as far north as the mouth of the Neekas River. From there, the spawn continues in scattered patches along the west side almost to the head of Spiller Inlet. Sea pens must therefore be restricted to the eastern shore. None-the-less, there are several areas of well protected deep water where pens could be located. ENHANCEMENT IMPLICATIONS The lake sampling program was, as noted earlier, designed to fill gaps in the data base which had been defined by Fedorenko (1987). Discussion in the following sections is therefore grouped under the headings Rearing Potential, Fresh Water Quality, Disease Profiles and Potential Competition and Predation so that comparisons can be made with Fedorenko's summary table. REARING POTENTIAL Productivity and Forage Base. Although the standing crop and forage base observed in the study lakes during 1987 would be severely impacted by the introduction of additional salmonids, the pre-introduction standing crops provide a convenient basis for inter-lake comparisons and evaluations of productivity and forage bases. System evaluations were made primarily on the basis of the August survey. The determining factors were; phosphate concentration, Chaoborus concentration, total zooplankton biomass, Daphnia biomass, and Daphnia size. Except for t. he Chaoborus concent rations, the parameters were ranked from highest (1) to lowest (13). Total phosphorous and zooplankton biomass were included as general indicators of lake productivity and the Daphnia parameters were included as representative of the fraction of total zooplankton which might serve as forage for juvenile sockeye (Hanson and Peters 1984, Goodlad et al. 1974), Bosmina could well have been included as the indicator of preferred prey (Koenings and Burkett 19871, but this would have biased the total index away from productivity indicators. Chaoborus densities were ranked negatively for two reasons. First, Chaoborus are zooplankton predators and may be competitors rather than forage at some times of year (K. Hyatt pers. comm.). Second, Chaoborus form dense, acoustic scattering layers in some lakes which can make hydroacoustic . sampling impractical. As a result, population sampling and benefit evaluation become more difficult or expensive. The results of the evaluation are shown in Table 12 where it can be seen by the mean ranks, that the systems were fairly closely clustered with Butedale Lake scoring somewhat higher than the others despite moderate Chaoborus densities. At the other end of the scale, Wyndham Lake was near the bottom of the list in all categories. The Yule Lake score was biased downward by incomplete phosphorous results. However, given the low zooplankton biomass, the system would not have rated much higher even if there were substantial concentrations of phosphorous. Existing Fish Populations Quantitative information on the fish populations of the study lakes is limited to the five systems which were successfully sounded in 1987. However, it appears likely that cutthroat, kokanee, Dolly Varden and sticklebacks are present in all of the systems and that the density of limnetic fish covers a considerable range (Table 8). In Link Lake (580 fish/ha), at the lower end of the scale, the potential for successful fish introduction is excellent, given a reasonable forage base. Red Bluff, Whalen and Cougar Lakes all have higher existing fish densities but may still have additional capacity. Sylvia Lake, at the upper end of the scale (7,600 fish/ha) appears to offer limited potential for additional fish unless the forage base is considerably more productive than is common in oligotrophic coastal lakes. Where fish density data were available the study lakes were ranked from lowest density (best) to highest (worst). Those lakes where no data were available, or where the fish densities were already high, were ranked at 10. The results are as follow: (1) Link, (2) Red Bluff, (3) Whalen, (4) Surf, (10) Sylvia, all unknowns (10). Downstream Passage With the exception of Namu Lake, all of the study lakes are above barriers to migration. Where stocks are propagated artificially, the upstream barriers are of lesser concern. Juvenile fishes must however, be able to migrate from the system without excessive mortality. It was therefore necessary to assess the probability of successful passage over the falls. Potential mortality at waterfalls is difficult to predict with any certainty. At one extreme, Richie (1956) investigated free fall mortality in migrating fishes and reported that, for fish <18 cm, the terminal velocity in air was lower than the lethal velocity of 16 m/sec. Thus, where small fish fall clear of a descending water column into a still pool, height is not a problem. It is difficult to compare these results with a natural waterfall. The development and operation of hydroelectric facilities has resulted in considerable research into fish passage problems. Ruggles et al. (1981) noted that, at most dams, physical injuries are related more to turbine problems than to spillway falls. None- the-less, at some installations, such as the Lower Elwha Dam on the Columbia system, significant mortalities resulted where water cascaded over a number of rock outcroppings in a highly turbulent manner before reaching the stilling pool,. After reviewing the literature, Ruggles et al. (1981) prepared a list of mortality factors. Some of the factors, such as stranding below spillways, are peculiar to dams and of no account here. Others, more applicable to natural falls included: - Direct physical injury, - Increased exposure to predation - Atmospheric gas supersaturation - Sublethal effects Direct physical injuries can occur when fish are subjected to striking obstructions such as rock outcroppings during the fall. Physical distortion and injuries can also result from the tumbling, and shearing forces within turbulent and rapidly decelerating water. Other sources of injury can include; abrasion, rapid deceleration and rapid pressure changes. It is apparently difficult to predict the relative importance of these factors without a detailed analysis of the structure and hydraulic conditions. Spillways of various designs and heights of up to 80 m, have recorded survivals of 54 - 100% among downstream migrant salmonids (Bell and DeLacy 1972). At chute type natural falls such as the 27 m falls on the Skykomish River in Washington, juvenile chinook, coho and steelhead were able to descend successfully and no losses were recorded. In comparison with these figures, most of the falls in the candidate systems are likely to pass a large portion of the downstream migrants without injury. In ranking the systems, it was noted that there are no falls on Namu Creek and that those on the Sylvia, Batchellor, Red Bluff and Ingram systems are all 5 m or less in height (Table 13). In the next rank are the systems which have larger falls (12 - 15 m) but are still likely to be easily passed. This includes the Wyndham, Yule, and Ellerslie discharges. The higher and more turbulent flows of the Whalen, Butedale and Sandell are more difficult to assess. The direct drops at Surf Inlet, Ocean Falls and Sandell Falls are near the lower end of the range of heights examined by Bell and DeLacy (1972). But as Ruggles et al. (1981) reported, these Table 13 Summary of outlet evaluation for downstream migration 1 System Outlet Type Mean Approximate height Gradient (7~) of highest falls (m) Rating* 'Wwdham Series of small falls and cascades 13 15 4 sy1via Steady series of cascades Batchellor Steady series of cascades Red Bluff Several cascades whalsn Continuous falls and cascades Surf River Concrete dam above short set of cascades Butedale Continuous turbulent falls Yule Series of falls ingram Series of cascades Ellerslie Tw sets of falls Link Concrete dm, cascades Namu Small creek, no obstructions Sandell Falls and cascades I J * (1 = best) heights are still sufficient to result in significant mortalities in turbulent plunge pools. Whalen and Butedale Creeks are continuous rapids and turbulent falls with mean grades of 12 and 20% respectively. It seems probable that some juvenile salmonid losses can be expected fprihr~ these descents. The systems with larger falls should not be totally discounted. The Alaska Department of Fish and Game (ADFG) has been outplanting sockeye and coho into lakes above migration barriers for some years. In most cases, they have found that out migrant smolts could successfully transit natural falls as long as there was an adequate plunge pool. Where there were losses associated with waterfalls, ADFG was able to concentrate the fish at a converging throat weir and construct a small diameter plastic pipeline to carry the fish around the obstruction. These systems require personnel on site and are therefore an increased cost. However, the initial capital costs are minimal. Pipelines have been used to by-pass falls 80 m in length and up to 40 m in height (J. Koennings, ADFG, pers. comm.). Cascading water falling into plunge pools frequently drives captured air to a depth sufficient to result in a solubility greater than at normal atmospheric pressure. Atmospheric gases may thus be supersaturated and lethal to fishes in flows below the obstruction (Ebel et al. 1975). The significance of supersaturation as a mortality factor in chronic cases varies with the degree of supersaturation, fish size, water depth and the components of the gases present. As a rule of thumb, a maximum total gas pressure of 103.8% is recommended for long term exposure (Jensen et al. 1986). Where freshwater migration routes and exposures to supersaturated conditions are short, such as the present study systems, juvenile fishes may be able to withstand somewhat higher supersaturation. Ebel et al. (1975) noted that where juvenile fishes were subjected to sublethal periods of supersaturation, they recovered when returned to normally saturated water. Plunge pools in all of the study systems were relatively small and the potential for high levels of supersaturation limited. Further, the short migration routes would render any exposure relatively brief. Supersaturation was therefore not included in the outlet ranking. Long term effects of sublethal stress can have catastrophic impacts on fish populations (Brett 1958). Although most investigations of fish passage at obstructions have focused on immediate mortalities, there do not appear to be any well documented long term effects of falls, particularly where downstream migration continued in freshwater (Ruggles et al. 1981). Where smolts move rapidly into salt-water, scale losses of 10% can result in 50% mortality. The short migration routes and absence of estuaries in the present study systems may thus present a problem. If there are scale losses or abrasions during passage over falls and chutes, there is little chance of recovery before the fish move into the marine environment. Estuaries also present an opportunity for migrant juveniles to adjust to temperature and salinity changes. Fish dropped from freshwater systems directly into the marine environment may suffer additional stress-related mortality during this adjustment. Unfortunately, in£ormat ion on the potential extent of losses due to sublethal stress associated with waterfalls of varying heights was not available and there was no way to evaluate the various sources of potential stress. Sublethal effects were therefore not included in the system rankings, although some of the concerns are addressed indirectly in assessments of other parameters such as physical injury and predation. Rearing Evaluation The evaluation of rearing potential was altered somewhat from Fedorenko (1987). Indirect measures of productivity such as shoreline length and development were replaced by measured parameters including phosphate concentrations and zooplankton density and composition. The overall rearing potential of the candidate systems are summarized in Table 14. The highest ranked system was Link Lake despite a poor rating for the potential safety of downstream migrants. The system is large and has very low existing fish densities. Even if the fish density can only be increased by a small increment, Link Lake could still produce a significant number of juvenile salmonids. This evaluation is relatively robust. Even if the forage base assessment were based on the June zooplankton results, which ranked Link Lake as one of the least productive systems, Link Lake would still be in the top 3 for overall rearing potential. Red Bluff Lake ranked second in rearing potential. It is much smaller then Link Lake, has a higher existing fish density and a poorer forage base. None-the-less, it offers much better downstream passage for juvenile fishes. The principal failing of Red Bluff Lake lies in the lack of net pen sites as the system discharges into the middle of Grenville Channel with only a very small bay. Ellerslie Lake is nearly as large as Link Lake and has good net pen sites. In addition it offers a moderate forage base and downstream safety. The system might have ranked higher if time had permitted lake sounding during the August survey. The 10 rating for existing fish population was arbitrarily assigned in the absence of further information. Tsble 14 Summary of rearid potential at candidate sites (1 = bast) Foxage Base Existing Safety of Adlability Mean 0vtral17 System Lake Size (a) and fish downstream of suitable Rating Rank Area Rating Productivity population pagefor sea-pen (ha) {Table 12) juveniles {b) sites {a) Whelen 2,200 2 6 3 8 8 5.4 4 Surf 1,300 3 5 4 10 5 5.4 4 Iwam 380 8 5 10 (c) 2 2 5.4 4 Nsmr 282 3 3 10 (dl 1 4 5.4 4 Butedale 557 6 1 10 (dl 8 3 5.6 5 Batcbllor 610 5 3 10 (c) 2 9 5.8 6 Yule 620 5 9 10 (c) 4 3 6.2 7 Safdell 327 8 6 1 0 tci 10 3 7.4 8 2 9 7 -4 Sylvia 483 7 9 10 (el 1I I n 1 Wyndharn 549 6 10 10 (f) 4 .-,Y f.0 10 (a) - Fedorenko (1 987) except Ingram and Ellerslie (b) - Table 13 (c) - nQtsounaed. {d) - Sonndinga undecipherable due !o cbwborao. (e) - High fish densities in soandin@. {f) - Blot sounded due to iughchsolzorus densities in zooplankton hauls. The Whalen, Surf, Ingram and Namu systems were all ranked equally at 4. Whalen Lake is large and had a moderate forage base and few existing fish but has hazardous falls and poor locations for seapens. The Surf Inlet chain is somewhat smaller than Whalen Lake and has slightly higher fish densities. It was also held back by poor downstream safety. Ingram and Namu Lakes are among the smallest of the study lakes. Their ranks were also reduced because of the absence of quantitive data on existing fish populations. In Ingram Lake, the absence occurred because the system was not sounded. The lack of data on Namu Lake is due to a dense Chaoborus layer which rendered sounding tapes indecipherable. WATER QUALITY Water quality of the study systems was ranked on the basis of eight key parameters which included: alkalinity, conductivity, hardness, pH, aluminium, calcium, copper and phosphorous. The results are shown in Table 15. It should be noted that all of the systems were deficient in terms of the recommended standards for hatchery use (Table 1). The highest ranked system, Namu Lake, is thus the best of a bad lot. On the other hand, salmonids were observed in almost all of the study systems and their ability to support fish rearing at low densities is apparent. Commercially significant stocks of sockeye are supported by other lakes in the study area with similar water quality including Curtis and Bonilla Lakes (Costella et al. 1983, Nidle et al. 1984). Alkalinity is a measure of the buffering capacity of water. It is of concern in hatchery settings as the byproducts of fish metabolism tend to result in increased water acidity. In systems such as those in the study lakes, where pH is already very low, the results could be critical. Further effects of low pH include: facilitating the dissolution of metals such as aluminium; and increasing the toxicity of others such as copper, lead and zinc which were in relatively high concentrations in all of the study systems. Soft, low hardness waters have also been related to increased incidence of kidney problems in hatchery reared fish (Warren 1x3). Sigma (1983) suggests that hatchery waters with hardness less than 20 mg/L would be cause for concern. Given these concerns, it is not recommended that any of the systems be used for incubating waters. However, it may be possible to improve the water quality through the addition of small amounts of sea-water. The results of the mixing program conducted at Butedale, one of the lowest ranked potential supplies, during the June and August surveys suggest that acceptable results could be obtained. This type of water treatment has not been tested locally on incubating fish and would undoubtedly increase the cost and complexity of facility operations None-the-less, there are supplies of well flushed sea- water convenient to each of the study lakes and the technique warrants further investigation. DISEASE PROETLES The pathogens and parasites found during the health check are all common in B.C. salmon stocks and are unlikely to limit production under normal circumstances. The virus IHN and IPN, which are of particular concern in artificially propagated stocks, were not found in any of the samples. The bacteria Renibacterium salmoninarum, which is the causative agent for BKD, was found in samples from Yule, Namu and Sandell Lakes. BKD is found in low levels in many B.C. hatcheries and generally causes few mortalities. It is of greater concern in salt-water environments where it has resulted in significant mortalities in pen-reared fish (D. Kieser, DFO pers. comm.). BKD has also been observed during the ocean migrations of anadromous salmonids however, there is little information available on its significance at this stage (Banner et al. 1982 & 1983). Yersinia ruckeri is responsible for enteric redmouth disease (ERM) and can cause significant mortalities among fish rearing in freshwater, particularly trout. It was found in samples from Whalen Lake where it occurred in nine of 19 Dolly Varden sampled, and from Sylvia Lake where only one of 18 cutthroat and 40 kokanee carried the bacteria. Most of the parasites found in the lake samples are carried by salmonids with little effect on the health of the stocks. Two possible exceptions include: Philonema sp. which was found in the Sylvia, Red Bluff, Butedale and Yule samples; and Diphyllobothrium sp. which was found only in Link Lake. The adhesions caused by these worms can interfere with spawning success if the damage is severe enough. Diphyollobothrium, can on occasion, have a severely debilitating effect on juvenile salmonids. Cage cultured juvenile chinook at the Marie Lake CEDP project in the Queen Charlotte Islands were severely effected by this tapeworm (D. Kieser, DFO pers. comm.). The disease profiles of the candidate systems were not ranked for three reasons. First, all of the parasites and diseases found are common to B.C. salmon stocks and are unlikely to limit productivity under normal circumstances. Second, there is no quantitive basis for evaluating the relative threats of BKD and ERM. Finally, there is as yet little information on the disease complements of potential donor stocks so compatibility can not be assessed. POTENTIAL COMPETITION AND PREDATION Competition Competition exists where one or more resources are in short supply. In lacustrine fishes, food, space and spawning habitat are commonly limiting (Keast 1978). Assuming that fish introduced to the study lakes are likely to be artificially propagated, and that they are most likely to be introduced where existing fish densities are low, then the competition faced by introduced fish is most likely to be based on the food supply. The information on existing fish populations suggests that, in the limnetic zone, the two most likely competitors are sticklebacks and kokanee (Table 9). Juvenile kokanee will exploit the same food resources as juvenile sockeye and are thus potential competitors. However, their numbers may be constrained by factors which do not impact on stocked sockeye. These include the availability or suitability of spawning habitat and a limited forage base for older, larger animals. In many lakes, juvenile sockeye must compete with sticklebacks for food resources. O'Neill and Hyatt (1987) demonstrated that limnetic sticklebacks exploit food types which are similar to those of juvenile sockeye and that sticklebacks could impact significantly on sockeye production. The problem is that not all sticklebacks are limnetic. Hyatt and Stockner (1985) reported that all of the coastal B.C. lakes which they studied contained sticklebacks, but only half of the lakes contained limnetic populations. In the present study, there were sticklebacks in the littoral areas of almost all of the lakes but these areas are used during the summer by both littoral and limnetic sticklebacks and the two cannot be readily distinguished. Sampling for the limnetic fish populations by trawling or other means was beyond the scope of the present study. Predation There is a potential for fish losses to predation in both the freshwater and marine environments. Within the study lakes, it is difficult to assess the potential for predation on introductions of limnetic fish. All of the systems appear to have cutthroat trout and Dolly Varden populations which are likely to be piscivorous. We do not have sufficient population data to assess the relative risk within the various lakes. The nature of the outlet will also have a serious impact on the potential for predation. Brown and Moyle (1981) noted that predation increased below falls and spillways where there were opportunities for predators to aggregate. Migrating juvenile salmonids were apparently stunned or disoriented by the passage and thus easier prey. Where migration routes include falls which drop directly into the sea, there is ample opportunity for predators to collect and losses could be significant. It has also been noted that where juvenile salmonids are released into enclosed bays or lagoons, there is an increased opportunity for predator aggregations and juvenile salmonid losses (Aimes MS 198?). In ranking the potential for predation in the marine environment, field surveys were limited to a brief reconnaissance of each river mouth. Whalen Creek, which flows into a broad channel leading directly to the sea was given the best ranking. Second was Namu Creek which flows into a small harbour leading to Fitz Hugh Sound. In the next rank were all of the systems which discharged directly into Grenville and Princess Royal Channels. This includes the Wyndham, Sylvia, Batchellor, Red Bluff, and Butedale systems. These steep sided channels limit the activities of some near-shore and estuarine predator species such as sculpins, although the juvenile salmonids must negotiate the length of the passage to get out. Yule and Sandell systems fell slightly behind the others as the juveniles must negotiate a small bay before reaching the channel. Ocean Falls, the Surf River and Ingram Lake are all located at the heads of inlets and juveniles migrating to the sea and there is an increased opportunity for predator aggregation. Ellerslie Lake ranks worst in this respect. On leaving the lake, juvenile migrants would have to avoid predators in the confined and shallow spaces of Ellerslie Lagoon. After leaving the lagoon, fish must migrate the length of Spiller Inlet and Channel. In considering the Ellerslie system's configuration, it should be noted that the predation problem may not be as serious as it seems. Other major salmon producing systems such as the Docee River discharge through tidal lagoons. The problem could, however, warrant concern in the early years of a project when the number of out-migrating salmonids is low relative to the numbers of predators. SUMMARY On the basis of the data collected to date, it appears that all of the study lakes are capable of supporting salmonids. None-the- less, the establishment of enhancement facilities would be practical in only a few instances and would entail the solution of some outstanding problems, primarily those of incubation water supply, downstream safety and fishery management. The overall results of the 1987 surveys are summarized in Table 16. Disease compatibility and marine water quality were not scored as there are, as yet, no data available. The systems were fairly closely clustered with only Link Lake distinctly better than the rest and Wyndham Lake clearly less desirable. It should be noted that the evaluation ranked the systems on a fairly arbitrary basis and different conclusions could be made if the systems were examined for a particular species or for a particular enhancement Table 16 Sunwry of a11 pauanleters exstrrined at candidate lakes. System Possible Availability Suitability Presence Rearing Fresh Site Disease Marine Potential Mean Owrail fishery of suitable of terminel of private potentials water construction profile water competition rank rating Conf licts donor stocks fishiN sector (d) quality & operation compatibility quality & predation (a> (b) site8 (c) interests (c! (4 costs (a) (f) (f) ($0 Lialr 9 6 4 1 1 2 1 ? ? 8 4.0 1 Namu 10 2 8 6 4 1 2 '? ? 2 4.4 2 Surf 6 3 2 5 4 2 6 ? ? 8 4.5 3 Whalen 6 1 7 5 4 5 8 ? ? 1 4.6 4 Brrtedale 6 2 7 2 5 9 3 ? .? 3 4.6 4 Red Bluff 4 3 10 5 2 3 4 '? ? 3 4.9 5 Sandell 7 10 N/A 3 8 1 4 ? ? 5 5.4 6 Yule 6 2 7 5 7 4 8 .? ? 5 5.5 6 Ellerslie 5 5 2 5 3 7 8 ? ? 10 5.6 7 Sylvia 4 3 10 5 8 3 9 .? ? 3 5.6 7 Itwarn 5 5 2 5 4 10 8 ? ? 8 5.9 8 Batchller 4 3 10 5 6 8 4 ? ? 3 6.0 9 Wy~~4 3 10 5 10 6 9 ? ? 3 6.3 10 (a) - Imludes isolation from wild stocks, Fedorenko (1 987) except Ingram and Ellerslie Lakes. (b) - Fedoreiko (1 987) plus Table 1 1. (c) - Fedorenko (1 987) except Ingram and Ellerslie Lakes. (d) - Table 14. (el - Table 1 5. (f) - further data required. (g) - see discussion 'Potential Competition and Predation' strategy. For example, the existence of seapen sites would not be important if fry were outplanted to lakes, or vice versa. Also, certain factors could be more important then others (an extreme case being 'go - no go'). At present, the factors have not been weighed. Link Lake had the best rating of the study systems on the basis of high scores in rearing potential, freshwater quality, private sector interests, and potential construction and operations costs. The lake's large size, low existing fish densities and acceptable forage base, combined with good sea-pen sites in Cousins Inlet, result in high potential for rearing juvenile salmonids despite problems in out-migration. Link Lake water quality is less than ideal for fish culture but it is among the best of the candidate systems and certainly good enough for fish rearing at low densities. It may also be possible to improve the water quality through the addition of saltwater during the incubation process. In terms of private interests, there is an existing pool of local labour and popular support. In addition, the potential for conflict with the various proposals for aquacultural or industrial activity in the area is limited. Infrastructure developed during the site's industrial past will result in reduced construction and operation costs relative to other candidate sites. The benefits of Link Lake were sufficient to outweigh potential problems in fishery management and potential predation. It should also be noted that, although the scoring system for rearing potential ranked the downstream safety at Ocean Falls as poor, this factor was outweighed by other considerations. In reality, unless safe passage around or over the falls can be assured, the stocking potential of Link Lake may be nil. Namu Lake was the second highest rated system. Donor stocks were more readily available than for Link Lake and water quality was slightly higher. However, these factors were outweighed by problems with fishery conflicts and the lack of a discrete terminal fishery area as well as some potential for conflicts wlth existing private sector activities in the area. It should also be noted that enhancement assessment would be difficult on this system as the dense Chaoborus layer makes sounding difficult. More expensive enumeration techniques, such as an outlet fence, could be required. The Surf Inlet system rated quite highly in terms of water quality and potential for a discrete terminal fishery (Table 16). The rest of the scores were in the mid-range except for the potential for predation which was high due to the system's discharge at the head of an inlet. Like Link Lake, this system flows over a dam and although this factor was considered in the assessment of rearing potential, it may prevent lake stocking. In addition, although existing water quality is fair and no trace could be found of effluents from past mining operations, the mine is about to re-open and further examination may be required. Whalen Lake ranked highly in terms of the availability of donor stocks and potential predation. Unfortunately, it also had a potential for high costs and management problems related to the presence of transient stocks in the potential terminal fishery areas. This system has also been rejected by a DFO Small Projects review which decided that coho fry outplanted from the Hartley Bay facility could not survive passage over the falls (M. Foye, DFO pers. comm.). Butedale Lake offers low construction and operation costs due to the existing infrastructure and the potential for hydroelectric power. It was downgraded somewhat due to poor freshwater quality, the absence of a discrete terminal fishery area, and the presence of transient stocks. None-the-less, some of the biological considerations including availability of donor stocks and rearing potential were fairly good. Potential problems which are not readily apparent in Table 16 include a dense Chaoborus layer which rendered echo sounding assessments of fish densities ineffectual, and high turbulent outlet falls which may have to be by-passed by migrating juveniles. Red Bluff Lake was rated fifth among the systems studied despite good potential for rearing, acceptable water quality, readily available donor stocks and a minimal danger of predation. The problems with this site were due to its location at the south end of Grenville Channel. There is little opportunity for a discrete terminal fishery and cost would be high during both development and operation phases. Water quality was very good in Sandell Lake and there is nearby labour and support. Unfortunately, the rearing potential is limited, and there are few good donor stocks available. Further, the potential for fishery conflicts is quite high in the Rivers Inlet area. Yule Lake ranked high in terms of donors stocks and low in terms of terminal fishery areas and costs. In all other areas, it was fair. Ellerslie Lake was ranked seventh among the study systems despite good rearing potential and suitability as a terminal fishing area. These were balanced by high costs of construction and operation as well as high potential for predation on out-migrating juveniles. It should be noted that the potential for predation may be over valued by the ranking system and would be of lesser concern to larger stocks. Sylvia Lake offers little rearing potential due to its small size and high existing fish densities. It ranked high in terms of donor stock availability and freshwater quality, but these were outweighed by its location in Grenville Channel and the attendant high costs and poor potential for terminal fisheries. Ingram Lake lies at the head of Spiller Inlet and this offers a good potential for a terminal fishery. However the system's potential is limited by small size, poor water quality and a high potential for predation losses among juvenile fishes attempting to transit the inlet. In addition, it is relatively remote and would have high construction and operation costs On the other hand, it should be noted that many of these problems could be overcome if the system were considered a satellite to operations at Ellerslie Lake rather than as an independent project. Batchellor and Wyndham Lakes share the problems of the other Grenville Channel systems including the lack of terminal fishing areas, and high costs. in addition, Batchellor Lake has poor water quality while Wyndham Lake has limited rearing potential. One failing which all of the candidate systems had in common was poor water quality for high density fish culture. While water quality was generally adequate for rearing at large, hardness, pH, alkalinity and conductivity were generally well below recommended levels for hatchery incubation and rearing. Mixing experiments which were conducted at Butedale suggest that the addition of salt water to a conductivity of 240 umhos/cm could increase hardness, pH and conductivity to acceptable limits without raising sodium concentrations to harmful levels. Alkalinity and calcium levels would, however, remain low. Alkalinity is is required to buffer the pH drop resulting from respitory carbon dioxide in rearing facilities (Sigma 1983). Given the low alkalinity water likely to result from salt water addition, it may be necessary to increase water flow rates through any facilities designed to use this technique. In a similar, vein, the variations in ocean surface salinity suggest that saltwater should be drawn from greater depths where salinity is likely to be more constant. Recommendations for further study The 1987 sampling program was developed as a reconnaissance level survey to provide data for use in planning and preliminary decision making. The data collected were sufficient to permit an evaluation of the relevant merits of the candidate systems and to point out some of the potential problems in the development of enhancement programs. There remain however, a number of areas which should be examined before the program proceeds much further. These include: 1. More detailed sampling Productivity, disease profiles and potential production estimates were all developed on the basis of a small number of samples. Given the variability inherent in a large lake system, the possibility of a significant error is quite large. This is particularly true of Link Lake where there were large variations in the forage base components between the June and August surveys and where logistics limited echo soundings to the southern half of the lake. In addition, the field survey budget did not permit detailed bathymetric survey of the candidate lakes. As the estimated volumes of the lakes are integral parts of the population calculations, and thus the estimates of potential benefit, it would be worthwhile to develop more accurate bathymetric and volume data. 2. Sampling potential donor systems. Once decisions have been made about the candidate lakes, more detailed work can be completed on matching potential donors. This should include comparisons of the limnology and estuarine components of the two systems as well as more exhaustive disease profiles. 3. Expanded search for incubation water To take advantage of the rearing potential of the study lakes, it will be necessary to either develop incubation facilities on site or transport fry from some other facility. If the former approach is used, an adequate incubation water supply will be required. To date, all of the systems have proved unsuitable for this purpose. One approach to this problem would be to examine and sample the tributaries of the leading candidate lakes as well as any nearby drainages. 4. Testing incubation waters Failing the discovery of an adequate natural incubation water supply, the effectiveness of salt-water mixing should be evaluated on incubating eggs. This should include a review of the literature and a field trial. The literature search should focus on sodium tolerance of sperm and the metals tolerance of alevins. The field trial could be attempted at any of the central coast facilities including the Snootli Hatchery or the CEDP hatcheries at Hartley Bay and Bella Bella. All three of these facilities have low- pH/low-hardness water supplies and are relatively close to saltwater. ACKNOWLEDGEMENTS J.R. Fielden and P. Lawrie assisted with the field operations. K.D. Hyatt and P. Rankin of the LEP Enhancement Assessment Unit provided equipment for lake soundings and and analytical skills for the estimation of fish populations and capacities. K.S. Shortreed and the staff of the LEP Limnology Lab in West Vancouver offered advice in the collection of productivity indicators as well as analyzing the zooplankton and phosphate samples. Water quality samples were analyzed at the DOE Cypress Creek Laboratory and at the MOEP Environmental Laboratory at U.B.C. The DFO Scientific Authority for the program was B.G. Shepherd. His advice and thoughtful editing were deeply appreciated. Aimes, J. MS 198-. Salmon stock interactions in Puget Sound: A preliminary look. In R. Hilborn (ed), Evaluation of Salmonid enhancement projects: Proceedings of a workshop. Can. Tech. Rept. Fish. Aquat. Sci. (in prep.) Atmospheric Environment Service (AES) 1982. Canadian climate normals: Temperature and precipitation 1951 - 1980, British Columbia. 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