Measuring the State of
Fish
Measuring the State of Fish
 There are many human
stressors that impact a fish
community and specific
fish species such as:
fishing, habitat loss,
invasive species (exotic &
range extensions),
pollution
 MNR utilizes standard
netting surveys to measure
fish status and some
invasive species
Measuring the State of Fish
 Other surveys are carried
out to measure the
stressors such as:
– Creel surveys to measure
fishing pressure
– Water testing to measure
pollution, chemical habitat
availability (O2, temp, N, P
etc.) and invasive species
– Physical habitat mapping to
identify spawning & nursery
limitations/opportunities
Measuring the State of Fish:
Standard Netting Surveys
 benefits
– A means of controlling some variables in nature and
hopefully measuring them
– Reduce sampling bias
– Can directly compare results year to year and across
different lakes measured using the same standard
technique
 Standard criteria
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Gear size, material, dimensions, configuration
Timing (water temperature, thermal stratification)
Number of sets per lake and set duration
Random selection of sites meeting standard criteria
Net orientation to shore and/or depth contours
Gear depth
Minimum net separation distances and duration
between reuse of sites
Measuring the State of Fish:
Standard Netting Surveys
 There are two main
types of gear utilized in
lakes
– Gill nets
– Trap nets
Measuring the State of Fish:
Other standard & non-standard gear
 Standard electrofishing protocol
developed for streams
 Other non-standard
gear that are useful in
certain situations
include: seine nets,
hoop nets, minnow
traps, dip nets,
electrofishing boats
Measuring the State of Fish:
Pros & Cons of Gill Nets vs Trap Nets
Gear Type
Cons
Gill Nets
Can be lethal if set too
long, some surveys utilize
shorter set durations to
minimize this
Some species not as
vulnerable to gill nets
(crappie, largemouth
bass, sunfish, eel)
Pros
 can gather more
information from lethal
sample: better age
structures, sex, sexual
maturity, contaminant
samples, stomach samples
Samples the entire lake
Easier & lighter to handle,
can utilize wider variety of
boats
Less time required to
complete survey, usually can
lift, sample and reset 10-12
nets per day
Measuring the State of Fish:
Pros & Cons of Gill Nets vs Trap Nets
Gear Type
Cons
Trap Nets
 heavy (dry weight 165 lbs)
and harder to handle
 boats need to be open at
front and minimum 16 ft
 more time required to
complete survey, usually can
only lift, sample and reset
four nets per day
 lake size, near shore slope
& aquatic vegetation can
limit # of suitable netting
sites
 fish smaller than 4” can
pass through mesh (perch)
Pros
 non-lethal sampling
Captures all fish species
inhabiting the near shore
area
Measuring the State of Fish:
Standard Netting Surveys
Trap Nets
Survey Name Targeted Fish Timing
Min. # net
sets
End of Spring
Trap Netting
(ESTN)
Walleye
Spring (MayJune)
Water 12C-18C
16 overnight sets
10 days on lake
Nearshore
Community
Index Netting
(NSCIN)
All near shore
species such as
bass, pike,
sunfish, crappie,
bullheads,
suckers, walleye
August to end
September
Water > 13C
16 overnight sets
10 days on lake
Measuring the State of Fish:
Standard Netting Surveys
Gill Nets
Survey Name Targeted Fish Timing
Min # net sets
Broad scale
All fish species
Monitoring (BsM)
Mid June to end
of September
Water >18C
12-55 overnight
sets, lake size &
depth dependant
3-10 days on
lake
Fall Walleye Index
Netting (FWIN)
Walleye, yellow
perch, cisco,
whitefish
Late September to
late October
Water 15C-10C
8-28 overnight sets
for lakes 10 to
5000 ha
3-6 days on lake
Summer Profundal
Index Netting
(SPIN)
Lake trout,
whitefish, cisco
Mid July to mid
September
25-44 two hour
sets for lakes 101000 ha
4-7 days on lake
Measuring the State of Fish:
Creel [Fishing] Surveys
 Provides:
– estimates of fishing
effort, catch rates &
total harvest by species
– Angler origins & visitor
types (daytrip, cottage,
paid guest, non-pd
guest etc)
– Size, weight, age of
harvested fish (if
collected)
Fish
species
Walleye
Pike
Bass
Trout
Fishing
effort
Catch
rate
Total
Harvest
Anglerhrs
No.
fish/hr
No. fish
6500
3200
8900
2200
0.75
1.10
1.45
0.15
2000
1300
5500
500
Angler Origin
CAN
USA
ONT
Local
Measuring the State of Fish:
Creel [Fishing] Surveys
 4 main types of creel surveys:
– Roving
 on the lake counting boats and talking to them
 Good for lakes where boats heading out from numerous locations
 Often incomplete fishing trip information, used to estimate a complete trip
– Access
 Interviewing anglers as they leave the lake from access point(s)
 Good for lakes where boats heading out from few locations
 Get complete fishing trip information, less estimation required
– Voluntary logs
 Books or forms handed out ahead of time to anglers
 Biased results if all large cross section of anglers don’t participate or only
fill out for successful trips
 Works best with participation incentives and/or on-lake coordinator
– Aerial boat counts
 Boats counted from aircraft
 Only gives estimate of fishing effort
 Cost of aircraft can be prohibitive
Measuring the State of Fish:
Creel [Fishing] Surveys
 Creel design:
– Final estimates are derived from “snap-shot” samples
obtained throughout a survey period
– Survey periods experience fluctuating levels of fishing
effort, catch rate, harvest etc. depending upon:
 Season: spring open fishing seasons, summer vacation, fall,
winter
 Day type: weekday vs weekend
 Period: morning, midday, evening; walleye lakes experience
three periods whereas lake trout & bass lakes one or two
 Area or lake basins: for larger lakes to ensure boat counts are
completed in 30-50 minutes
– Need “snap-shot” samples on 2-3 occasions, regardless
of weather (rain or shine), for each combination of the
above
Measuring the State of Fish:
Creel [Fish] Surveys
How to conduct a roving creel survey
On randomly chosen sample day:
1. Boat around the lake [basin] and count boats that are
fishing, don’t stop to interview during counts, should
complete in 30-50 minutes
2. Interview as many fishing boats as possible. Introduce
yourself & ask if they’d mind answering a few quick
questions:
1.
2.
3.
4.
5.
6.
What time did you start fishing today?
Are you staying on the lake, if so, where?
Where do you live?
What are you fishing for today?
Have you caught anything? (record all species caught, often
need to prompt for other species)
Have you kept anything? If yes, and you are sampling this boat
1.
Do you mind if we take lengths, weights and scales from your fish?
Plan to carry out two boat counts and 1-2 interview periods
per sample day
Measuring the State of Fish:
SAFETY FIRST!
 Volunteer agreement forms cover those listed on
the form:
– Volunteers do not qualify for workplace safety &
insurance benefits
– MNR has purchased Accidental Death &
Dismemberment Policy on behalf of volunteers
– Ontario General Liability Protection Program protects
volunteers from suits arising through injury caused to
another person or another person’s property while
performing duties listed on volunteer agreement form
– Volunteers dealing with the public will carry volunteer
identification provided by MNR
Measuring the State of Fish:
SAFETY FIRST!
 The Min. of Labour & Transport Canada require certain
safety training & equipment is provided & on board:
– Safety kit: Cell phone kept in waterproof container, buoyant throw
rope (15m+), working flashlight, flares, fire extinguisher, whistle or
some other sounding device, bailing bucket, map of lake, running
lights if on lake ½ after sunset or before sunrise
– Let someone know where you will be and expected time off lake
– All boat operators must have a Pleasure Craft Operators Card
– One approved personal flotation device per passenger
– One paddle or an anchor with 15m+ cable, rope or chain
– Dry land Man-Over-Board training & dry land putting on PFD in
water training
 Reminder to stay off or get off the lake if thunderstorms are
approaching or other weather conditions such as high
winds make it unsafe
How Can Stewardship Councils and Other
Partners Get Involved ?
 There is reimbursement funding
available ($500-$2500) through
the Community Fisheries &
Wildlife Involvement Fund
(CFWIP) to cover:
Equipment & supplies
 Deadline to apply is February
1st
 Applications and guidelines
available from your district office
CFWIP
 CFWIP $ cannot be utilized to pay wages (except for heavy equipment
operator costs)
 Work must be completed by volunteers
 Funding provided after submission of receipts for equipment and
materials (applicants must be willing to initially cover purchasing costs)
 Equipment purchased with CFWIP $’s is OMNR property and may be
returned to OMNR upon completion of project
 OMNR staff available to meet with stewardship councils to provide
project ideas and technical guidance