Abstracts of Fisheries Management Reports, Technical Circulars
and Project Reports of the Fisheries Branch

Daiva O. Zaldokas & Debra L. Aird

B.C. Fisheries Branch, 2204 Main Mall, U.B.C.,
Vancouver, B.C. V6T 1Z4

Fisheries Technical Circular No. 91


Lirette M.G. and D. Tredger.  1991. Polley and Bootjack Lakes Creel 
Survey, 1990.  B.C. Environment, Williams Lake, B.C. Regional Fish. 
Rep. No. CA 911:21p.
A creel survey was conducted on two popular sport fishing lakes in the 
Cariboo, Polley and Bootjack lakes.  Between June 2 and September 2, 
1990, 407 anglers were interviewed and 151 rainbow trout were sampled 
to provide information on the recreational fisheries of these lakes.  The 
number of boats angling on Polley and Bootjack lakes were counted from 
shore and aircraft to determine total effort.  Anglers fished an estimated 
7,891 hours (3,446 days) to catch 15,412 trout (11,825 harvested) from 
Polley Lake during the May to September fishery.  Bootjack Lake anglers 
fished 5,670 hours (2,324 days) to catch 7,515 trout (5,829 harvested).  The 
trout captured from both lakes averaged 290 mm (145 to 360 mm) and 
were mainly 4+ years old (2+ to 6+).  Over 80% of the fish harvested 
appeared to have spent at least one year rearing in their nursery stream 
prior to migrating to Polley and Bootjack lakes.

Doligan, R.B. and M.G. Lirette.  1991.  Fisheries Assessment of Upper 
Maud Creek.  B.C. Environment, Williams Lake, B.C. Regional Fish. 
Rep. No. CA 912:12p.

An exploratory assessment of juvenile rainbow trout in the "upper" Maud 
Creek drainage was conducted to determine current abundance and 
provide estimates of potential migrant production to Maud Lake.  
Rainbow trout fry were found in high densities at all sample sites in both 
Maud (4.3/m2) and Rudy Creeks (3.2/m2). Collectively, the total 
population of juvenile rainbow trout was estimated to be in excess of 
110,00 fish.  Gill net sampling for rainbow trout in Sandy Lake confirmed 
the presence of sport-fish in this lake.  Water quality and quantity 
requirements to protect the fishery resource are discussed.

Lirette, M.G.  1991.  West Road (Blackwater) River air survey of angler 
use, 1990.  B.C. Environment, Williams Lake, B.C. Regional Fish. Rep. 
No. CA 913:25p.

An air survey of angling use in the West Road River watershed was 
carried out between June 21 and September 17, 1990.  Boats on fifteen 
lakes and boats/vehicles on or near seven sections of the river were 
counted on approximately eleven weekend days and nine weekday days.  
Mean boat count for weekend and weekdays varied for lakes and stream 
sections depending on their accessibility.  Good access resulted in high 
weekend use while poor access to lakes or stream sections resulted in 
higher weekday use.  Mean boat counts were used to estimate angler use 
in days fished.  The largest fisheries were on Tsacha Lake (1843 angler 
days), Marmot Lake (1672 days) and zone 2 (1095 days) and zone 3 (1047 
days) of the Blackwater River mainstem.  The total estimated use on the 
Blackwater River was 4,333 angler days.  The air survey data provides a 
relative comparison of angler use between lakes and river section in the 
watershed.  It also provides the means to monitor future changes in the 
various lake and stream fisheries of the West Road River.  Survey costs 
and effectiveness are discussed.

Griffith, R.P.  1991.  Blackwater (West Road) River Assessment of 
Existing and Potential Resident Rainbow Trout Production Downstream 
of Kluskoil Lake.  R.P. Griffith and Associates, Sidney, B.C. for B.C. 
Environment, Williams Lake, B.C. Region Fish. Rep. No. CA-914:176p.

During the period of critical low flows in September 1990, an assessment 
was conducted of existing and potential fish production in the Blackwater 
(West Road) River drainage below Kluskoil Lake. Results were based on 
intensive field sampling and sophisticated analytical methodologies.  
Electrofishing in juvenile habitat resulted in the capture of 11 different fish 
species.  Rainbow trout was the species with highest frequency of 
occurrence, followed by chinook salmon, the only other salmonid species 
captured.  Non-salmonids were principally found in mainstem areas 
(Blackwater, Nazko, and Baezaeko rivers).  Rainbow juveniles were found 
at few mainstem sites (and in low numbers), but were by far the most 
numerous species in the 12 smaller tributaries that were sampled.  Based 
on production modelling, rainbow fry and parr densities in mainstem 
habitat were grossly below theoretical capacities.  Similarly, standing 
stock of rainbow fry was well below respective capacity in most of the 
smaller streams sampled. In contrast, rainbow parr appeared to be near 
(or above) capacity in all of the smaller streams where they occurred.  In 
terms of mainstem populations of catchable-size fish, various estimates 
indicate that the Blackwater system (below Kluskoil Lake) is functioning 
at about half its theoretical potential, based on production modelling for 
such populations.  The cause appears to be lack of recruitment.  Survival 
of rainbow fry seems low in mainstem habitats (due to non-salmonid 
predators and competitors), emphasizing the importance of older recruits 
(parr) from tributaries.  All indications suggest that a limitation in suitable 
habitat for parr is imposing a similar limitation on mainstem recruitment, 
and ultimately the numbers of catchable-sized fish in mainstem areas 
(notably the Blackwater River).  The principal limiting factor appears to be 
the severity of low flows in most tributary streams, exerting greatest 
impact on parr habitat.  since the current level of mainstem recruitment 
appears to rely on all available parr production, all smaller tributaries 
(and their flows) should be afforded full habitat protection (even small 
producers).  Habitat enhancement should focus on increasing the 
abundance/availability of parr habitat in tributaries by such means as 
barrier/obstruction removal and/or flow augmentation (if feasible).  
Various options are suggested.