US Long-Term Ecological Research Network
(revised 6/28/02)
NOTE: This protocol is for each sample site. Eight sites are sampled on each lake.
 
Day Crew
 
Equipment checklist:
 
25 (50 halves) Minnow Traps & Floats                       Measuring board
25 (50 halves) Crayfish Traps & Floats                      GPS                                                               
25 slices Beef Liver (6.5 packages)                           Balances (5, 10, 30g)
25 slices of white bread (2 bags)                                Computer
16 Reflectors                                                              12 volt batteries
Forceps                                                                       Data sheets
Scale Envelopes and paper (write in rain)                  Full fuel tank
ID keys                                                                        PFD’s
Forceps                                                                       Oars
Small Tubs                                                                  Aerators
Minnow nets                                                                Measuring tape
 
  • Place 1 slice of white bread in each minnow trap and 1 slice of beef liver in each crayfish traps. Minnow traps have 2.5cm diameter openings and crayfish traps have 7.6cm openings.
 
  • Locate the beginning of each site using the GPS. 
 
  • Set three minnow traps and three crayfish traps in shallow water (approx. 1 m), spaced approximately 15m apart along the 50m riparian transect corresponding with plots A, C, and E. Set the crayfish and minnow traps within two meters of each other.
 
  • Traps are fished for approximately 24 hours. Crayfish are identified to species, counted per trap, and returned to the lake. Fish caught in either the crayfish or minnow traps are identified to species. Bluegill, pumpkinseed, rock bass, largemouth bass, smallmouth bass, yellow perch, and walleye are measured for total length, weighed and scales taken if necessary (see “processing fish” below). Any other species caught are identified to species, counted for each trap, and returned to the lake.
 
  • After pulling the traps at each site, set out the reflectors for electrofishing. The reflectors should be placed 25m before the start of the adjacent riparian transect and 25m after the end of the transect.


Night Crew
 
Equipment Checklist:

Fishboards (large and small)                                      ElectrofishBox
Balances (5, 10, 30, 60, 100, 500, 1000 grams)        Forceps
Computer                                                                    Headlamps                             
Scale envelopes                                                         Cliplights (2)
Batteries (2-12 volts)                                                   Running lights                                                
Full fuel tanks (generator and boat)                            Aerators
PFD’s                                                                          GPS
Oars                                                                            Dip nets (2)                
Big Tubs (3)                                                                Small tubs
Rubber boots and gloves (2 pairs)                              Spotlight (2)
 
  • Locate each site by finding the reflectors with the spotlight.
 
  • Electrofish eight 100m transects on each lake after sunset.
 
  • Follow a 1.5m depth contour along the shoreline, but make sure to electrofish near littoral structure (docks, cwd, etc).
 
  • Two dipnetters will net all fish regardless of size and place them in the livewell.
 
  • The driver should record the average DC electrical output in amps and the time taken to complete each transect on the driver datasheet.
 
* Note – Communication between the driver and the netters is essential. It is the netters responsibility to let the driver know about obstructions (logs, rocks, etc) in the water and to let them know if they have to back up for missed fish. Don’t be shy, the driver has to hear you over the generator.
                                                                                                                       
PROCESSING FISH
 
  • Sort fish into small tubs by species if necessary.
 
  • Measure the total length (from nose to end of caudal fins pinched together) in mm and weight in grams for these seven species:
 
Bluegill                                     Pumpkinseed
Largemouth Bass                    Smallmouth Bass
Rock Bass                              Yellow Perch
Walleye
 
  • Take several scales from 5 fish of each of these species (bluegill, largemouth bass, smallmouth bass, yellow perch, and walleye) from each 10mm size class. Keep track of the number of samples taken from each of these species using the scale tally sheet.
 
  • For yoy fish (for yoy lengths see Table 1), take lengths and weights of 30 fish of each of the above seven species per lake. If possible take several of the 30 required fish from different locations, not all from the same site.
 
  • Weights should be taken with the appropriate sized spring balance – the fish should be in the mid-range of the scale.
 
 
  • Record the date, lake code, site number, fish ID number, species, length, and weight on the scale envelope.
 
  • Take the scales from behind the left pectoral fin if looking at the fish from the dorsal side. Place at least 5 scales in the scale envelope.
 
  • Take the third dorsal spine from 5 yellow perch and bluegill for each age class (Table 1). Place it in the scale envelope.
 
  • Identify all other fish and keep a count for each species for each trap or electrofish run. 
 
  • If a fish cannot be positively identified, preserve it for later identification.
 
  • Revive fish that have not recovered by holding them by their dorsal surface in the water and gently rocking them to the left and right to move water across the gills.
 
 
* Note - Remember to hang pesola spring balances to dry after each sampling. If the springs rust they are not reliable. Spring balances are to be calibrated weekly.
 
Table 1
   
Age and Growth (TL in mm) of primary Centrarchid and Percid Species (Becker 1983)
 
                         
Species
1
2
3
4
5
6
7
8
9
10
11
Source
SMB
61
135
208
269
318
359
399
424
447
465
480
Bennett (1938)
LMB
71
165
246
297
335
353
386
424
450
470
490
Bennett (1937)
PS
54
79
106
128
151
171
 
 
 
 
 
Parker (1958)
BG
44
75
96
120
140
154
165
174
169
180
184
Schloemer (1939)
RB
40
62
83
106
128
149
168
185
203
214
222
Hile (1942)
WLLY
135
221
348
421
483
526
551
566
587
592
 
Schloemer and Lorch (1942)
YP
69
109
140
180
201
236
 
 
 
 
 
Snow (1969)
 
Protocol Format
Process
Protocol ID
biocom_fish1
Protocol Type
field