Kansas Department of Wildlife and Parks
STANDARD FISH SURVEY TECHNIQUES FOR SMALL LAKES AND RESERVOIRS
Fifth Edition
REVISED BY THE
Fish Survey Techniques Committee Ron Marteney, Chairman Lowell Aberson Chuck Bever Sean Lynott John Reinke Mark Shaw
June 2010 TABLE OF CONTENTS
INTRODUCTION...... 1 RANDOM SAMPLING...... 1 AQUATIC NUISANCE SPECIES...... 2 AQUATIC DATA ANALYSIS SYSTEM (ADAS)...... 3 EQUIPMENT SPECIFICATIONS...... 4 STANDARD...... 4 Electrofishing...... 4 Core-mesh gill net (Monofilament)...... 7 Trap (fyke) net (‘A” mesh)...... 8
SUPPLEMENTAL...... 8 Gill Net (Monofilament)...... 8 Fry Trawl...... 9 Otter Trawl...... 9 Rotenone Sampling...... 9 Shoreline Seining...... 10 Trap Net (1” Mesh)...... 11 Baited Hoop Nets (Tandem)...... 11
SAMPLING TECHNIQUES...... 12
STANDARD...... 12 Electrofishing...... 12 Core-mesh gill net (Monofilament)...... 14 Trap Netting (1/2”Mesh)...... 15
SUPPLEMENTAL...... 17 8-Month Standard Creel Survey...... 17 Reservoir Winter Creel Survey...... 19 Urban Channel Catfish /Trout Creel Survey...... 22 Fry Trawl...... 25 Otter Trawl...... 25 Rotenone Sampling...... 25 Shoreline Seining...... 27 Trap Netting (Large Mesh)...... 27 Electrofishing (Blue Catfish Option)...... 28 Electrofishing (Shad Option)...... 29 Electrofishing (Flathead Option)...... 30 Baited Hoop Nets (Tandem)...... 31
SAMPLING SPECIFIC SPECIES...... 33
FAMILY CENTRARCHIDAE...... 33 FAMILY ICTALURIDAE...... 34 FAMILY PERCIDAE...... 35 OTHER SPECIES...... 36
CONFIDENCE INTERVALS...... 37 REFERENCES...... 41 APPENDIX I 43 INTRODUCTION
This document is organized to provide users with quick access to procedures for sampling fish in small lakes and reservoirs. Both water types are sampled with same gears (see EQUIPMENT SPECIFICATIONS).
ANY DEVIATION FROM THE SAMPLING TECHNIQUES DESCRIBED IN THIS MANUAL MUST HAVE PRIOR APPROVAL FROM A FISHERIES SECTION REGIONAL SUPERVSIOR.
The desirability of standardized sampling programs is recognized by the fisheries profession (Willis and Murphy 1996, Bonar et al, 2009). In general, standardized sampling programs use specific techniques to collect samples at randomly selected locations and similar dates each year. The Kansas Department of Wildlife and Parks (KDWP) began standardized sampling of small lakes and reservoirs in 1979.
This sampling manual updates the fourth edition of KDWP’s Fish survey techniques for sampling lakes and reservoirs (Marteney and Mosher 2004). As in earlier editions, the purpose of this document is to reduce variation in data collection by establishing standard techniques. Therefore, some techniques that may prove useful for special surveys are also listed. This document relies heavily on information compiled in Standard Methods for Sampling North American Freshwater Fishes (Bonar et al. 2009).
Strategies for sampling small lakes usually differ in some important ways from those used on reservoirs because of physical and biological differences in the two water types. For example, the number and location of sample sites in small lakes and reservoirs often differ because of impoundment size and shape. More effort is required to adequately sample large impoundments that have more habitat and species diversity than small impoundments. Sampling dates for small lakes frequently differ from those selected for reservoirs because of thermal differences which influence fish distributions and activity on a given date. Small lakes tend to warm faster than reservoirs in spring and cool more quickly in autumn. As a result, most species of fish spawn earlier in small lakes than in reservoirs. Other physical characteristics that influence the development of sampling strategies include rates of water exchange and sedimentation, water clarity, and lake morphometry. Sampling must be adjusted to account for differences in fish distributions, activity, and vulnerability to a sampling method in a particular environment.
RANDOM SAMPLING
KDWP has chosen to use a random sampling design. Prior to 2010 sampling was done using preselected or “index” sites. More fish may be caught at these selectively chosen index sites than at randomly chosen sites. However, index sites can be expected to produce biased estimates of some indices when surveying fish populations, especially indices of abundance and length structure (Wilde and Fisher 1996; Dauwalter et al. 2004). Moreover, the relative bias between subjectively and randomly chosen sites can differ among waters such as reservoirs (Hubbard and Miranda 1988). Therefore, to be able to compare fish population samples either among water bodies or within water bodies over time, some form of randomization to initially select sampling sites is needed to ensure that the survey is unbiased.
To assist in selecting random sampling sites, lake maps have been produced that have numbered-grid overlays. The grid sizes are 100 x 100 m for small impoundments and 333 x 333 m for large impoundments. Prior to sampling fish populations in a given water body using a particular gear type, grids are randomly chosen from an appropriate sampling frame. A sampling frame is the subset of grids that can be sampled effectively with that gear type. For example, the sampling frame for electrofishing sites would only include grids which include segments of shoreline, not grids in deep offshore areas where there would be little chance of catching fish by electrofishing. Additionally, to calculate population indices that can be compared among water bodies, the sampling frames should use the same selection criteria (eg. water 1.8 to 5 m deep for core gill nets). A randomly selected grid should only be used once per sampling gear per year. Grid selection
1 within a sampling frame will depend upon existing lake conditions. District Fisheries Biologists should develop a sampling frame for each of the major sampling gear types for each water body they will be sampling.
Once an appropriate sampling frame is chosen, using a random technique to select sampling sites within that sampling frame will allow indices to be computed that can be compared among water bodies and over time.
AQUATIC NUISANCE SPECIES
Sampling Activities
The movement of field gear and equipment can potentially provide a pathway for the introduction of invasive species. It is important to know what species occur in the waters that are to be sampled; however, this is not always possible. Therefore, it is vital to implement the standard practice of treating and cleaning all gear and equipment as if they were contaminated before moving from one water body to another.
If sampling is scheduled for several sites in the same body of water, if sampling is repeated at the same site over a period of time, or if sampling progresses in a downstream direction, it is not necessary to disinfect gear between sampling efforts. However, when in doubt, consider all gear and equipment contaminated and implement appropriate control measures to decontaminate these objects before they are moved.
Decontaminating sampling gear when moving between water bodies can substantially increase time and cost. Ideally, multiple sets of sampling gear and equipment should be purchased and kept solely for work in specific waters. The use of multiple sets or dedicated gear and equipment for work in different waters can reduce the time component and substantially reduce the probability of unintentional introductions compared to decontamination. Both approaches have a cost and must be factored into sampling schedules and project budgets.
Control Measures
The most effective control method is simply to avoid moving gear and equipment from one location to another. Where possible, gear should be procured specifically and solely for use in water bodies known to harbor invasive species. This strategy effectively blocks a primary invasion pathway and eliminates the necessity of decontamination procedures that must be implemented otherwise. However, it is usually impractical to have multiples of some large equipment items (eg. trucks, boats, and trailers).
If it is not possible to have multiple gear sets for different waters, it is critically important to decontaminate nets, waders, boots, and other gear (including boats, trailers and fish hauling boxes) to a level that will eliminate most invasive organisms (including plants, vertebrates, invertebrates, and many parasites and diseases). General decontamination procedures used to prevent the spread of zebra mussels, for example, are effective for plants and other organisms as well. KDWP’s accepted method of disinfecting gear and equipment is washing with high-pressure hot water. Water temperature must be greater than 140°F and contact time should be greater than 10 seconds. Special attention should be paid to cracks, crevices, and other hidden spaces where invasive species might escape visual detection. Engine cooling and generator cooling water lines should be purged once the boat is removed from the water. It is important to properly clean and rinse the lower units of boat motors. Boat live wells, holding tanks, and bilges should be drained on site and completely dried before leaving the water body being sampled. Then, a thorough visual inspection should be made to confirm that no visible contaminants were missed.
Hazard Analysis and Critical Points (HACCP) Plans are being developed for each KDWP administrative region to specify approved procedures which will be used to avoid the inadvertent spread of ANS through activities carried out by agency personnel.
2 AQUATIC DATA ANALYSIS SYSTEM (ADAS)
The KDWP maintains an Aquatic Data Analysis System (ADAS) (Hartmann and Mosher 1978) to store and summarize data collected by standard sampling. The system stores fishery data in a readily accessible form that can be summarized for biologists to evaluate and use in developing management plans for each body of water. In addition, these data are used to make regional and statewide evaluations of lake and reservoir fisheries through time.
Data Collection
The type and amount of data collected during each sampling effort depends upon the management objectives for a given water body. If a sample is being collected primarily to monitor a fish population over time, less information may be necessary than would be required to assess the impact of newly enacted special regulations or evaluate changes in stocking regimes.
For each species of interest (eg. gamefish, panfish, and primary prey species) a minimum of five fish > Stock size (Gabelhouse 1984) from each 10 mm length group should be measured to the nearest mm (TL) and weighed to the nearest gram. If more than five fish from a 10 mm length group are collected, the remaining individuals can be measured and recorded in a 10 mm length group to be entered in ADAS as group data.
If large numbers of Young-of-Year (YOY) crappie or gizzard shad are collected, a subsample of ~ 100 individuals should be measured and recorded in 10 mm length groups. The remaining individuals can then be counted, their total number recorded, and released. They can later be assigned to appropriate 10 mm length groups - based on the length frequency of the measured subsample - and entered into ADAS as group data.
ADAS can use the above data to calculate Catch Per Unit of Effort (CPUE), length frequency, and condition factors (Wr).
Data Entry
To make comparisons between gear types (eg. various types of electrofishing boats) it is critical that archived data be associated with sampling equipment used in collecting those data. The ADAS database currently has over 90 gear types which increases the possibility of inadvertently selecting the wrong sampling gear when entering data. The use of generic gear descriptions, such as ‘ELECTROFISHING-DC, 220V’, is not acceptable when a more specific description, such as ‘ELECTRO- SMITH ROOT, DC’, exists.
To ensure timely archiving of fisheries data, deadlines for uploading sampling results to ADAS have been established. Statewide and Regional analyses - in addition to District Biologist’s annual Progress Reports and Management Plans - require the ADAS archives to have the most current data available.
Deadlines for ADAS data submission
Spring Electrofishing : August 1 Fall Sampling (gillnets & trap nets): December 1 Supplemental samples: December 1
Data Analysis
Statistics generated by ADAS from standardized data include catch rate or catch per unit effort (CPUE), length frequency, and fish-condition. Length-frequency data are categorized using the five-cell Relative Stock Density (RSD) model developed by Gabelhouse (1984). Fish condition is indexed by Relative Weight (Wr) for
3 species with available Standard Weight (Ws) equations. More traditional K (Fulton-type) factors are utilized for the remaining species. See Anderson and Gutreuter (1983) for a discussion of both Wr and K factors.
Scientific names of all fishes discussed in this manual are listed in Appendix I. The appendix also indicates gears that can be used to sample important species.
ADAS User’s Guide
Instructions for use of ADAS for entering and uploading sampling data can be found on the KDWP Fisheries and Wildlife Division’s intranet site:
http://fw1.wp.state.ks.us/fw1/FW1-Home/Fisheries/Web-Applications/ADAS2/ADAS
EQUIPMENT SPECIFICATIONS
STANDARD EQUIPMENT
Electrofishing
KDWP currently uses electrofishing boats manufactured by Smith-Root, Coffelt, and Midwest Lake Management. It is recognized that differences in design exist between manufacturers, however, when preparing bid specifications for future purchases of electrofishing boats consideration should be given to the following general design features:
I. Description
A. Boat
1. Preferred is metal
a. 3.6-6.1 m (12-20 ft) long
b. 1.5-2.0 m (5.0-6.0 ft) wide
B. Outboard Motor
1. Balance need to access shallow water and cruise shore at low speed with power requirements to navigate long distances.
2. Must be in electrical continuity with the boat hull
C. Power Generator
1. Single-phase or three-phase able to produce 230 V and 5 kW or higher
2. Must be in electrical continuity with the boat hull
4 D. Control Unit (Electrofisher)
1. Capable of 60 Hz pulsed DC output, high voltage, with adjustable voltage, amperage, duty cycle (pulse width) and frequency output
2. Includes amperage and voltage meters, a dial rheostat and timer to track energized field time
E. Anode array design varies by manufacturer but should fall within the following specifications:
1. Suspended from boom(s) extending forward 2.4-2.5 m (approx. 8 ft) from the bow
a. Distance between the foremost ends of a double boom configuration should be 1.9-2.0 m (6.0-6.5 ft) (Miranda and Kratochvil 2008)
2. Anode array hangs from the end of the boom
a. Array is made up of 6 - 20 droppers
b. Droppers are evenly spaced in a circle of 91.4 - 101.6 cm (36 - 40 in) diameter
3. Each dropper consists of a stainless steel cable or tube 4.8-15.9 mm (1/8-5/8 in) diameter (4.8 mm recommended)
a. long enough to submerge 0.3-0.9 m (12-36 in) below the water surface
F. Cathode
1. Hull of the boat
G. Disconnect (Safety Switch)
1. A foot-activated disconnect in the bow to control field activation
2. Additional disconnects may be placed in the bow and near the control unit
H. Power Output
1. 2,750-3,250 W at 115 pS/cm ambient water conductivity for warm and coolwater fishes
2. Optimum operation occurs at a field size of 250 volts and field strength of 6 - 7 amperes. Individuals using Smith-Root and Coffelt units should refer to the owners manual for most efficient operation. 5 I. Frequency
1. 60 Hz pulsed DC for warm and coolwater fishes.
J. Boat Operation
1. In standing waters, operate the boat at 1-3 km/h (0.6-2.0 mph) along shallow (<3 m [10 ft]) nearshore areas
2. Forward progress may require meandering to parallel the shore, and to avoid obstacles
3. Sporadic backing up to retrieve fish and exit pockets along the shore may be required
K. Field Activation
1. Field activation is managed by the netter
2. Field is continuously activated during forward progress
3. Deactivate to avoid potential hazards and while backing up
L. Dip Nets
1. 6.4 - 12.8 mm (% - lA in) mesh
2. 30-60 cm (12-24 in) deep
3. fiberglass handles sufficiently long to allow netters to retrieve fish from the far end of the anode array
M. Netters
1. Two for most situations and for safety
2. One when catch rates are low
N. Livewell
1. Suitable livewell positioned behind the bow within reach of the netter(s)
2. Water is aerated to maintain high levels of oxygen and agitated to release carbon dioxide
3. Exchanged frequently so that fish do not show signs of stress
6 O. Calibration
1. Annual checks (may be conducted more frequently)
a. Check all electrical connections for corrosion
b. Check the entire system for continuity to the tips of the anodes
c. Check for proper operation of the kill switches (safety pedals)
d. Check resistance between each electrode and the control box
2. Electrodes must be cleaned often enough to remain shiny (no accumulated mineral deposit)
Core-mesh gill net (Monofilament)
I. Description
A. Net Type
1. Monofilament, 8 panel, sinking
B. Panel Sizes
1. 3.1 m (10 ft) long X 1.8 m (6 ft) deep
C. Mesh bar size
1. 19, 25, 32, 38, 44, 51, 57, 64 mm (0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50 in)
D. Monofilament diameters corresponding to mesh sizes above
1. 0.28, 0.28, 0.28, 0.33, 0.33, 0.33, 0.40, 0.40 mm (0.011, 0.011, 0.011, 0.013, 0.013, 0.013, 0.016, 0.016 in)
E. Mesh order 1. 38, 57, 25, 44, 19, 64, 32, 51 mm (1.50, 2.25, 1.00, 1.75, 0.75, 2.50, 1.25, 2.00 in)
F. Hanging ratio
1. 0.5 7 G. Top line
1. Poly-foam float line of % inch diameter braided nylon rope.
H. Bottom line
1. 30 lb/600' leadcore rope Sufficient weight to ensure negative buoyancy.
Trap (fyke) net FA” mesh)
I. Description
A. Net type
1. Modified fyke net consisting of a sinking trap and a lead; all netting 13mm (A in) bar knot-less nylon, a black asphalt-type coating will reduce abrasion and improve net life
B. Lead
1. One, 15-30 m (50-100 ft) long, shorten in steep situations; 0.91 m (3 ft)high, hanging ration 0.33
C. Trap
1. Two 1.2 X 1.5 m (4 X 5ft) rectangular frames each with a center brace; frames 0.6 m (24 in) apart with inwards mesh trap that tapers from the first frame to the second ending in a 102 mm (4 in) diameter opening; behind frames are four 0.77 m (30 in) diameter hoops, 0.6 m (24 in) apart, with mesh funnel between first and third hoops; cod end with purse string closure
SUPPLEMENTAL SAMPLING EQUIPMENT
Equipment listed below may be used to collect supplemental data on fish populations. It is NOT to be substituted for Standard Equipment (see above) without prior approval from a Fisheries Section Regional Supervisor.
Gill Net (Monofilament)
I. Description
A. Type and mesh - Monofilament net, with a single bar mesh.
Fry Trawl
I. Description 8 A. Trawl of 1/32-inch Delta weave nylon mesh capped with a detachable 4-inch diameter collection cup at the end.
1. Length - 18 ft.
2. Mouth a. 30-inch diameter b. 0.5 meter squared area. c. hoop constructed of 5/16-inch steel rod.
3. Bridles - plastic coated braided steel cable.
B. Towing warp of 'A-inch braided nylon and variable length.
C. Twenty foot security rope and float attached to cod end.
Otter Trawl
I. Description
A. Trawl of 'A-inch mesh nylon with a A-inch mesh nylon sock cod liner.
1. Length- 18 ft.
2. Mouth - When blossomed approximately 17ft. wide and 3ft. deep
3. Foot Line - 17 ft. long and weighted with lead and chain.
4. Headline - 14 ft. long and fitted with Styrofoam floats.
*Use of this equipment requires a minimum of 40 Hp outboard for towing.
Rotenone Sampling
**** ROTENONE s a m p l in g r e q u ir e s a p e r m it f r o m th e KANSAS DEPARTMENT OF HEALTH AND ENVIRONMENT (KDHE) PRIOR TO USING FISH TOXICANT****
I. Specifications
A. Block Net
1. Mesh size - 12.7 mm (A in) bar mesh
2. Floats - sufficient to ensure the float line is held above the water’s surface.
3. Weights - sufficient to ensure that the bottom line rests solidly along the bottom.
9 B. Rotenone
1. Liquid - 5.0% active ingredient or equivalent, 2.5% synergized ProNox™.
2. Application - apply heavy enough to ensure a total kill 2 to 3 ppm; up to 5 ppm if bullheads or golden shiners are abundant.
Shoreline Seining
I. Description
A. Minnow seine
1. Length and depth a. 6.1 X 1.22 m (20 X 4 ft) 2. Mesh a. 6.4 mm (% in) Delta 3. Brailes a. 1.8 - 2.5 m (6 - 8 ft) long (PVC or wood. Sturdy enough to pull the net) 4. Float and leadlines a. 29.5 kg (75 lb) leadcore bottom line and floatline with floats evenly spaced on the top line
5. Bag dimensions a. No bag Bag seine
1. Length and depth a. 9.1 X 1.8 m (50 X 6 ft) 2. Mesh a. 6.4 mm (% in) Delta 3. Brailes a. 1.8 - 2.5 m (6 - 8 ft) long (PVC or wood. Sturdy enough to pull the net) 4. Float and leadlines a. 29.5 kg (75 lb) leadcore bottom line and floatline with floats evenly spaced on the top line
5. Bag dimensions ' a. The bag (1.8 X 1.8 X 1.8 m [6 X 6 X 6 ft]) is incorporated in the center of the seine. Thus the seine contains 3.65 m (12 ft) wing on each side of the bag 10 C. Beach seine
1. 15.2 X 1.8 m ( 50 X 6 ft) with 12.7 mm (A in) mesh
2. used to supplement minnow seine.
Trap Net (1” Mesh)
I. Description
These nets are identical to the standard trap net described previously, except that the webbing is 25 mm (1 in) bar mesh of size 9 multifilament nylon.
Baited Hoop Nets (Tandem)
I. Gear Specifications
A. Hoop Net
1. Webbing - 25 mm (1in) bar mesh of size 15 multifilament
2. Dimensions - 3.35 m (11 ft) long
3. Hoops - seven fiberglass hoops ranging from 0.76 m (2 A ft) outside diameter (o.d.) at the front hoop and tapering to 0.61 m (2 ft) o.d. at the rear hoop.
4. Throats - 2 - Fingered crowfoot-style
a. tied to the net at the second and fourth hoop
b. rear throat is further constricted by tying the throat strings together about 6 inches from the cod end of the throat.
B. Bridles
1. Length - Approximately 0.91 m (3 ft)
2. Attached between the cod end of one net and the mouth of the next net in the series.
C. Bait Bags
1. 2 bags for each net (6 bags / HNS)
2. 305 X 305 mm (12 x 12 in) with 3.2mm (1/8 in) mesh
3. A drawstring with a lace-lok makes opening and closing the bag easier. 11 D. Bait
1. Type - Cheese logs (Boatcycle Inc. Henderson, TX., www.boatcycle.com)
2. Amount - Approximately 2.7 kg (6 lbs) per net (1.4 [3 lb] lb/ bait bag)
E. Anchor
1. Attached to the tail end of the series.
2. Of sufficient weight to hold the series in place and prevent it from collapsing.
SAMPLING TECHNIQUES
STANDARD TECHNIQUES
Electrofishing
Electrofishing is an efficient sampling procedure to evaluate black bass and other sport and non-sportfish populations by utilizing catch per unit effort, length-frequency, and body condition. Electrofishing samples should be conducted annually on lakes with length limit regulations to evaluate length limit effects. Fall night electrofishing for YOY walleye, saugeye, wipers and white bass is also an effective tool to measure yearly reproductive or stocking success of your target species. For more information on increasing electrofishing efficiency see Miranda (2005); Miranda and C. R. Dolan (2003); Miranda and C. R. Dolan (2004); Miranda and A. B. Spencer (2005); Miranda and M. Kratochvil (2008)
I. Operations
A. Direct-current (DC) electrofishing is preferred.
B. Optimum operation occurs at a field size of 250 volts and field strength of 6 - 7 amperes. Individuals using Smith-Root and Coffelt units should refer to the owners manual for most efficient operation.
C. 2,750-3,250 W at 115 pS/cm ambient water conductivity for warm and coolwater fishes
D. Time of day selected for sampling depends on lake clarity, depth and habitat. Night electrofishing may be necessary in clear-water impoundments.
12 II. Effort
A. Catch per hour is an efficient method of quantifying catch. Therefore, operators must take care to record only the energized field time to minimize bias.
B. Catch per unit effort may change for habitat types. Therefore, it is necessary for an impoundment to be divided into discreet grids that can be easily sampled. This will allow better comparisons from year to year, thus making it possible for managers to better analyze populations. Dividing the sample locations will also facilitate handling of fish by processing them close to capture sites and removing them from holding boxes before they become too stressed. Comparisons among habitat types will also improve through multiple-grid sampling on lakes. Recent research has also shown that 10-minute electrofishing segments on larger impoundments have produced comparable results to sampling the entire shoreline (Miranda et al. 1996). Large impoundments will have a minimum of 10 randomly selected suitable grids using 10-minute electrofishing sample segments. Small impoundments should have a minimum of 1 hour or l lap of the shoreline (in separately recorded and entered 10-minute sample increments).
C. Catch per unit effort will change from daylight to dark. Therefore, it is important to maintain a similar schedule from year to year, and to note sampling time during collection.
III. Sampling Frequency and Reporting
A. Black bass samples will be taken just prior to or during the spring spawning period when water temperatures are between 60 and 70 degrees F. Samples taken during this time frame portray the most reliable size structure for the population.
B. Supplemental black bass data can be collected in the fall. Night samples are required during the fall period. (Fall black bass samples may be applicable at impoundments where not disturbing spawning adults is a management priority.)
C. YOY walleye and saugeye samples are best taken during the fall when water temperatures drop to approximately 60 degrees F (Borkholder and Parsons 2001).
D. Scale samples are periodically necessary on lakes with length limits to assess impacts of regulations on fish growth and age distribution.
E. Length and weight of fish collected will be entered into PC ADAS at the field level and electronically uploaded for addition to the archives.
Core-mesh Gill Netting (Monofilament Nets)
Core-mesh gill-netting data are utilized to assess populations of many fishes in Kansas waters, including sport, commercial and prey species (Appendix I). The use of core-mesh gill nets does not ensure that the length structure of the sampled fish is representative of the true length structure of the fish population because mesh-size selectivity and efficiency influence catch rates of various sized fish. Mesh-size selectivity influences the length range of fish effectively caught within a particular mesh size, and primarily depends on fish length and shape, mesh size and hanging ratio, and method of fishing (Hamley 1975). 13 I. Effort
A. Each core mesh gill net set per night composes one unit of effort
1. The amount of sampling effort needed depends upon survey objectives and the precision of CPUE estimates. Initial effort (Net Night, NN) for each waterbody will be determined by the surface acreage of the impoundment as follows:
Impoundment Size Initial (acres) Effort (NN) <50 3 50-99 4 100-299 6 300-999 8 1000 - 2499 10 2500 - 4999 12 5000 - 8999 15 >9000 20
B. Units of effort should be increased to reduce the coefficient of variation among samples.
1. Each core mesh net will equal one “unit of effort” for each night it is set
II. Frequency of Collection
A. Standard core-mesh gill-netting samples will be collected each Fall between October 1 and November 15 or sampling should occur when water temperatures drop below 20° C (68° F). Gill nets should be set during the late afternoon and retrieved the following morning so that the sampling period encompasses both crepuscular periods.
III. Collection and Reporting
A. Sampling Sites.
1. Sampling sites should be randomly selected from the grids for each lake (Appendix II) that have been determined to be appropriate for gill nets.
a. Identify samples collected with a grid number
b. Some grids may be unsuitable for sampling with this gear due to physical changes at the lake, such as water level fluctuations. In this case, selections should be randomly made from grids where suitable conditions exist. 14 B. Net Placement
1. Deployment and retrieval of core-mesh gill nets should follow the procedure described by Hubert (1996).
a. Each net should be set in water 1.8 to 5 m deep, perpendicular to shore on the bottom (i.e. bottom set).
2. Net set variability:
a. All sets are to be horizontal, negative buoyancy sets.
b. The nets should not extend into an area of anoxic hypolimnetic water.
c. The net-end that is closest to shore should be randomly determined for each net set.
C. Data are recorded separately for each gill net. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
D. Scale samples should be collected when age and growth analysis is desired.
Trap Netting (1/2” Mesh)
I. Sampling
A. Units of Effort
1. Each net per night equals 1 net night of effort
2. Required effort is dependent upon lake size; more effort is necessary on larger lakes or if mean catches are highly variable.
Impoundment Size Initial (acres) Effort <100 2 100 - 299 4 300 - 999 8 1000-1499 10 1500-1999 12 >2000 16
15 B. Sample Period
1. Nets will be fished from before sunset to after sunrise and run within 24 hours of the time the nets were set.
II. Frequency of Collection
A. Standard trap-netting is done in the fall between October 1and November 15 or sampling should occur when water temperatures drop below 20° C (68° F). Trap nets should be set during the late afternoon and retrieved the following morning so that the sampling period encompasses both crepuscular periods.
III. Collecting and Reporting
A. Sampling Sites.
1. Sampling sites should be randomly selected from the grids for each lake (Appendix II) that have been determined to be appropriate for trap nets.
a. Identify samples collected with a grid number
b. Some grids may be unsuitable for sampling with this gear due to physical changes at the lake, such as water level fluctuations. In this case, selection should be randomly made from grids where suitable conditions exist
B. Net Placement
1. Set perpendicular to the shore with the frame in an upright position. Each net should be set in water 1 to 5 m (3 to 16 ft). Ideal locations will be those with a gradually sloping bottom. The net should not extend into an area of anoxic hypolimnetic water. Sets with the frame exposed above the water line may cause the trap to roll over.
C. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
SUPPLEMENTAL SAMPLING TECHNIQUES
The standard sampling techniques described above have been designed to provide the minimum information required for planning and evaluating fishery-management programs. For a variety of reasons, additional information may be useful to gain better insight on reproduction, recruitment, growth, and mortality of some fish species. Some supplemental sampling techniques, such as creel censuses, can be costly and time consuming to conduct. For this reason, they are not typically done on an annual basis. In some cases, a special permit is required before initiating a supplemental sampling regime. The use of supplemental sampling techniques is at the discretion of the District Biologist with approval from a Regional Fisheries Supervisor.
16 8-month Standard Creel Survey (Supplemental)
A creel survey provides valuable data on angler demands and fish harvest for a lake. Although this information is costly, it is invaluable to the overall management of a lake and should be conducted periodically.
The following is a general description of the creel census conducted by the Kansas Department of Wildlife and Parks. More specific information on schedules and field procedures may be obtained by contacting the Emporia Research & Survey Office.
Survey Design - The generic creel survey employs a randomly stratified sample scheme. Sampling efforts consist of 2-hr. (lakes) and 4-hr. (reservoir) survey periods organized to reflect gross variations in user patterns influenced by month, time of week (week days or weekend days/holidays), and time of day (morning, midday and evening). At SFL’s anglers actively fishing from shore and boats are counted at the beginning and at the end of each sample period and are recorded as “instantaneous”. At reservoirs, anglers are counted as the clerk travels around the reservoir completing interviews. These counts are recorded as “progressive”.
Additionally, one hour is set aside at reservoirs during which time clerks interview boat anglers at randomly selected boat ramps. These counts are not included to project total pressure, but the success of interviewed boat anglers is used to project total harvest. Total angling pressure (hours of angling effort) is estimated fromthe mean number of anglers per count. The fishing pressure exerted on weekdays and weekend days/holidays are independently calculated as follows:
P=FH
Where P = total fishing pressure in angling hours F = harmonic mean number of anglers per count H = total fishing hours (fishing hours per day times the number of days per month or year)
Survey Units - Each impoundment in this creel survey format is identified by an assigned four digit number. Larger impoundments or an impoundment with discreet areas of interest to be measured, may be assigned unit and sub-unit numbers to accommodate data separation needs. If you plan to measure a fishery requiring this multiple unit structure, contact your Section Supervisor for further information and plan coordination.
Sampling Structure - High angler use months (April, May and June) will be sampled more often than light use months (March, July, August, September and October). High use months will receive 36 hours of sampling time per month per unit at SFL’s and 72 hours of sampling at reservoirs. Light use months will receive 24 hours of sampling time per month per unit at SFL’s and 48 hours at reservoirs (Table 1).
In some cases, two survey periods may be scheduled to be conducted on the same day. The two survey periods will always be treated separately. In instances where more than one survey has been scheduled for the same day in consecutive time frames, survey periods will not be run “back to back”. A minimum of one hour will separate the two survey periods.
On large reservoirs the surveys can consist of a randomly selected 3-hour count and interview period every creel day. An additional one hour stay at a boat ramp is utilized to provide better completed trip information from boat anglers. Larger reservoirs are divided into subunits for creel censuses.
Table 1. Monthly structure of an 8-month, random-stratified creel survey with a 2-hour sampling period at Kansas state fishing lakes. Numbers in ( ) reflect sampling effort for reservoirs. 17 # WE # WD Or Holiday Total Total Periods Periods Periods Hours Month Per Unit Per Unit Per unit Per Unit March 6 6 12 24 (48) April 9 9 18 36 (72) May 9 9 18 36 (72) June 9 9 18 36 (72) July 6 6 12 24 (48) August 6 6 12 24 (48) September 6 6 12 24 (48) October 6 6 12 24 (48)
Sampling Procedures - Days have been divided into three time frames: morning, midday and evening. Length of time frames has been standardized according to the duration of daylight hours (Table 2). A random sampling schedule is provided using these criteria. Each creel survey sample period will be two or four hours. During this time, two instantaneous count of anglers who actively fishing will be made, one count at the start of the sample period and one at the end of the period at SFL’s, while one progressive count will be made at each reservoir unit. Angler interviews will be made after the initial count and be discontinued in time to make the final count.
Table 2. Daily time frames standardized according to the duration of daylight hours.
Day Length Month (Time) Morning (Hrs) Midday (Hrs) Evening (Hrs) (Hrs) March (CST) 0700-1100 (4) 1100-1530 (4) 1500-1900 (4) 12 April (CDT) 0630-1130 (5) 1130-1530 (4) 1530-1930 (4) 13 May (CDT) 0630-1130 (5) 1130-1630 (5) 1630-2130 (5) 15 June (CDT) 0630-1130 (5) 1130-1630 (5) 1630-2130 (5) 15 July (CDT) 0630-1130 (5) 1130-1630 (5) 1630-2130 (5) 15 August (CDT) 0630-1130 (5) 1130-1630 (5) 1630-2130 (5) 15 September (CDT) 0700-1200 (5) 1200-1600 (4) 1600-2000 (4) 13 October (CDT) 0730-1130 (4) 1130-1530 (4) 1530-1930 (4) 12
Instructions for use of IPAQ (pocket PC)
Instructions for use of IPAQ and other hand-held computers used for collecting creel census data can be found on the KDWP Fisheries and Wildlife Division’s intranet site:
http://fw1.wp.state.ks.us/fw1/FW1-Home/Fisheries/Web-Applications/Creel
Completed Surveys Completed creel surveys will be uploaded monthly using the following procedure: To upload files to the main server: 1. Open the creelmaint program that is located in your creel folder (c:\creel\creelmaint.mdb). 2. Click Create Upload and fill in the appropriate boxes for the data to upload. 18 3. Click Upload and wait until it is complete. (This may take a while depending on file size.) 4. Upload as many months and impoundments as necessary. 5. Once completed, close the program and go to the creel webpage. http://fw.wp.state.ks.us/creel/creel.asp 6. Click Upload creel data. 7. Click the Browse... button, and look in your c:\creel folder. Double-click on the impoundment upload file that was created earlier. (You will be looking for a filename in the form PPPP.mmyyyy-mmyyyy.mdb, where PPPP is the Impoundment code, and mmyyyy is a month/year date range.) 8. Click the Upload button to submit the file. 9. Repeat steps 6 through 8 for each additional upload file you may have created. 10. Upload your c:\creel\creelerrors.mdb file, so we can repair errors that may have encountered during synchronization. Your uploaded data will be checked over before being archived. I will send a paper copy with a monthly report. A final database will be available for you in the future when all uploaded data is received and archived
Reservoir Winter Creel Survey (Supplemental)
Survey Design The Generic Creel Survey employs a randomly stratified sample scheme. Sampling efforts consist of 4-hour survey periods organized to reflect gross variations in user patterns influenced by month, time of week (week days vs. weekend days/holidays) and time of day (morning, midday and evening). The survey season spans four months, 1 November through 28/29 February. Anglers actively fishing from shore and boats are counted at the beginning and at the end of each sample period; these counts are recorded as PROGRESSIVE.
Sampling Structure All winter months receive 48 hours of sampling time per month per unit (see Table 1).
Of the 48 hours sampled per month on each unit during light use months, 36 hours will be spent conducting traditional progressive creel survey, and 12 hours will be spent collecting completed trip interviews at boat ramps.
Sampling Procedures Days have been divided into two frames: morning, and afternoon. Length of the time frames has been standardized according to the duration of daylight hours (see Table 2). Because the four hour sample periods may have the potential of starting at several different times within the chosen period, start points should be randomly selected from all possible start times to complete the survey within 4 hours. Each creel survey sample period is four hours. During the first three hours of the period a progressive count on anglers and angler interviews will be made as the clerk traverses the unit. The clerk must judge the rate of progress as anglers are being interviewed and adjust travel and interview time to assure that anglers using the entire unit are counted. If this is not possible, an adjustment to the angler count must be made at the end of the count period to reflect total anglers present within the unit. A percentage estimate is acceptable. NOTE: Do not count boat trailers as an indication of the number of boat anglers. Only count the individual anglers that you can see.
19 Table 1 RANDOM STRATIFIED CREEL SURVEY Length of sampling period: Reservoirs - 4 Hrs
MONTHLY STRUCTURE
# Weekend/
# Weekday Holiday Day Total Total
Sampling Periods Sampling Periods Sampling Periods Hours Sampled
Month Per Unit Per Unit Per Unit Per Unit November 6 6 12 48
December 6 6 12 48
January 6 6 12 48
February 6 6 12 48
Table 2 DAILY TIME FRAMES
Length of Month Time Morning (Hrs) Afternoon (Hrs) Day (Hrs) Nov-Feb (CST) 7:00AM-12:00PM 5 12:00PM-5:00PM 5 10
Interviews at Boat Ramps Additional interviews will be conducted at pre-selected boat ramps exactly as those collected for the traditional creel survey, except that only boat anglers coming into the ramp will be interviewed. The majority of these interviews will therefore be completed trips.
20 Instructions for use of IPAQ (pocket PC)
Instructions for use of IPAQ and other hand-held computers used for collecting creel census data can be found on the KDWP Fisheries and Wildlife Division’s intranet site:
http://fw1.wp.state.ks.us/fw1/FW1-Home/Fisheries/Web-Applications/Creel
Completed Surveys See instructions in 8-month Standard Creel Survey section (above).
Urban Channel Catfish/Trout Creel Survey (Supplemental)
Survey Design
The most appropriate survey design to document the contribution of channel catfish and trout and stockings to urban creels is one whereby stocked fish are closely followed. To monitor each channel catfish and trout stocking, it is advisable to mark the stocked fish until it becomes apparent how quickly stockings are diminished. The urban/trout creel survey is conducted over a ten day period (Table 1), allowing each stocking to be followed, where day 0 (immediately following stocking), and days 1, 3, 5, 7, and 10 post stocking are creeled. Day 0 may be creeled immediately following the stocking, or at a later time period. Creel periods must be defined by whether the creel occurs in the first 10d period within the month, second 10 d period within the month, or whether the creel crosses into a second month (Table 1).
Time periods and start times (Tables 2 and 3) must be randomly generated (Table 4), most conveniently with a calculator or spreadsheet. These time periods are used to design the creel survey only. As an example, consider the following to generate a time period and start time for day 1 of a March rainbow trout stocking. Suppose when the random number button on a calculator is pushed the number 0.55 is returned. This would mean a midday time period is selected (Table 4). Next a start time needs to be determined. Suppose when the calculator's random number button is pushed this time the number 0.22 is returned. This would mean the start time would be 1130 (Table 4). Time periods and start times do not need to be evenly distributed over the 10-day creel period, but new time periods and start times should be randomly generated if they are clearly biased (e.g., only morning time periods are generated). Over the duration of the creel survey season time frames vary in length. Since the two hour sample period has the potential for beginning at a multiple of start points, start points have been randomly selected from all potential 30 minute intervals. Creel surveys conducted during March-October would utilize Kansas' standard time frames based on daylight hours (Table 2). Channel catfish sampling (March-October) consists of two hour survey periods randomly selected from one of three time periods (morning; midday; evening) (Table 2). For the urban/trout creel design, time periods for trout surveys during November-February would consist of two hour survey periods randomly selected from one of two, five hour time periods (Table 3), due to reduced daylight hours during winter.
Sampling Procedures
Each creel survey sample period is two hours. During this time, two instantaneous counts of actively fishing anglers are made one count at the start of the sample period and one at the end of the period. Interviews of anglers are then made after the initial count and discontinued in time to make the final count. It is important to interview as many completed trip anglers as possible.
Pocket Creel Instructions The iPAQ handheld computers will be used for conducting the creel census. Instruction manual for care, use, and operation of the iPAQs and the Pocket Creel Program will be provided for your reference. Instruction manuals can also be accessed through the internet at: http://fw.wp.state.ks.us/creel/iPAQ instructions.pdf
22 Table 1. Creel periods for Kansas Urban/Trout Creel design
Creel Period Portion of Month Creeled 7 First 10-day period that falls completely within a month 8 Second 10-day period that falls completely within a month 9 Any 10-day period that crosses into another month
Table 2. Daily time frames standardized according to the duration of daylight hours
Month Morning Hours Midday Hours Evening Hours Day Mar* 0700-1100 4 1100-1530 4 1500-1900 4 12 Apr 0630-1130 5 1130-1530 4 1530-1930 4 13 May 0630-1130 5 1130-1530 5 1630-2130 5 15 June 0630-1130 5 1130-1630 5 1630-2130 5 15 July 0630-1130 5 1130-1630 5 1630-2130 5 15 Aug 0630-1130 5 1130-1630 5 1630-2130 5 15 Sept 0700-1200 5 1200-1600 4 1600-2000 4 13 Oct 0730-1130 4 1130-1530 4 1530-1930 4 12
Table 3. Random time periods for surveying Kansas rainbow trout fisheries
Time Period Time 1 0700-1200 2 1200-1700
23 Table 4. Time period and start time random numbers for Kansas Urban/trout creel
Time period random numbers
March - October November - February
Random # Time Period Random # Time Period 0.00-0.33 Morning 0.00-0.49 Morning 0.34-0.66 Midday 0.50-0.99 Evening 0.67-0.99 Evening
Start time random numbers
March September Start Time Start Time Start Time Random # Morning Midday Evening Random # Morning Random # Midday Evening 0.00 - 0.19 0700 1100 1500 0.00 - 0.14 0700 0.00-0.19 1200 1600 0.20 - 0.39 0730 1130 1530 0.15 - 0.28 0730 0.20-0.39 1230 1630 0.40-0.59 0800 1200 1600 0.29-0.42 0800 0.40-0.59 1300 1700 0.60-0.79 0830 1230 1630 0.43-0.56 0830 0.60-0.79 1330 1730 0.80-0.99 0900 1300 1700 0.57-0.70 0900 0.80-0.99 1400 1800 0.71-0.84 0930 0.85-0.99 1000 April Start Time Start Time Random # Morning Random # Midday Evening October 0.00 - 0.14 0630 0.00-0.19 1130 1530 Start Time 0.15 - 0.28 0700 0.20-0.39 1200 1600 Random # Morning Midday Evening 0.29-0.42 0730 0.40-0.59 1230 1630 0.00 - 0.19 0730 1130 1530 0.43-0.56 0800 0.60-0.79 1300 1700 0.20 - 0.39 0800 1200 1600 0.57-0.70 0830 0.80-0.99 1330 1730 0.40-0.59 0830 1230 1630 0.71-0.84 0900 0.60-0.79 0900 1300 1700 0.85-0.99 0930 0.80-0.99 0930 1330 1730
May - August November - February Start Time Start Time Random # Morning Midday Evening Random # Morning Evening 0.00 - 0.14 0630 1130 1630 0.00 - 0.14 0700 1200 0.15 - 0.28 0700 1200 1700 0.15 - 0.28 0730 1230 0.29-0.42 0730 1230 1730 0.29-0.42 0800 1300 0.43-0.56 0800 1300 1800 0.43-0.56 0830 1330 0.57-0.70 0830 1330 1830 0.57-0.70 0900 1400 0.71-0.84 0900 1400 1900 0.71-0.84 0930 1430 0.85-0.99 0930 1430 1930 0.85-0.99 1000 1500
Instructions for use of IPAQ (pocket PC)
Instructions for use of IPAQ and other hand-held computers used for collecting creel census data can be found on the KDWP Fisheries and Wildlife Division’s intranet site:
http://fw1.wp.state.ks.us/fw1/FW1-Home/Fisheries/Web-Applications/Creel
Completed Surveys 24 See instructions in 8-month Standard Creel Survey section (above).
Fry Trawl (Supplemental)
The fry trawl can be an effective method for sampling newly hatched fish. It is especially effective to sample gizzard shad between 10mm and 20mm total length. Fish of all species seem better able to avoid the net when they reach 20mm, thus decreasing the effectiveness of the trawl. Because of the effectiveness for sampling smaller fish, the fry trawl can be efficient tool to better document time of spawning activities.
If used, data collected during trawling activities must be comparable. Comparisons should be made only between surface trawls or subsurface trawls. Data can be better quantified if digital flow meters are used with the trawl. If flow meters cannot be accurately used, a standard trawl time (eg. 10 minutes) may be substituted. It should be noted, however, that the volume of water strained will depend upon boat speed. A constant speed should be maintained to accurately compare results. High boat speeds may create a wake in front of the net that will repel fry, therefore, a speed that just maintains the net at the surface may be most effective.
I. Effort
A. Sampling during normal spawning periods should be conducted weekly to verify spawning time.
B. Tows should be of a standard duration (time or distance) that best fits the impoundment.
C. Night trawls may be required sample shad, especially in clear water.
D. If available, a flow meter should be used to determine the total volume of water sampled. If unavailable, volume should be estimated by multiplying distance sampled by the area of the net opening.
II. Collection and Reporting
A. Identify and measure fish captured to the nearest mm; enumerate by cm length group when overly abundant.
B. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Otter Trawl (Supplemental)
Contours and lake-bottom composition prohibit the effective use of otter trawls on most small Kansas lakes. The use of this equipment is, therefore, at the discretion of the individual biologist.
Rotenone Sampling (Supplemental)
25 Rotenone may be used to evaluate cove standing crops, or instantaneous YOY fish production (spot surveys). These methods will require netting off of a known area to determine quantitative data.
The use of rotenone REQUIRES A PERMIT which is obtained through the Kansas Department of Health and Environment (KDHE) PRIOR to using fish toxicant.
I. Frequency
A. Rotenone samples should be collected between July 1 and August 31.
II. Collection
A. Select a cove representing a range of habitat types
B. Determine area and volume of the cove.
C. Block cove or area to be sampled the morning of the collection date.
D. Mark fish
1. Collect a representative sample of fish from outside of sample area.
2. Mark, fin clip or tag, and release into sample area
3. Record number and species fish released.
E. Collect fish
1. First day
a. Collect and separate fish into 10mm groupings
b. Count all specimens by length group and species; bulk weigh by species.
c. Randomly subsample 10 fish from each cm length group, measure these fish to the nearest mm and weigh to the nearest gram.
d. Check fish for marks and record these separately to determine percent recovery after the rotenone application.
2. Second day
a. Collect and separate and count each species into 10mm groupings.
b. Weigh and measure any individuals of species or length groups
26 not recorded the first day.
c. Check fish for marks as on the first day.
3. Third day
a. Check for additional fish, police the area, and remove the block net.
Shoreline Seining (Supplemental)
Shoreline seining can be an efficient procedure to evaluate prey abundance and YOY production and is encouraged if special management plans call for the enhancement of reproduction of sport fish or prey production.
I. Effort
A. One standard “Swingle” drags (90° arcs) per station.
B. Determine grids which provide suitable seining stations covering as many habitat types as possible.
C. A minimum of 20 hauls will be made at suitable random locations when samples are collected on large reservoirs.
II. Frequency
A. Samples should be collected from May to October.
B. Frequency of sampling will be at the discretion of the biologist.
C. Night samples may be required for clear lakes where young fish and shad avoid the shoreline during daylight hours.
III. Collection and Reporting
A. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Trap Netting (Large Mesh) Supplemental
Larger-mesh nets are acceptable for special nettings where supplemental data for large fish is sought, such as spawning walleye. The use of A-inch mesh nets is required to obtain better data on small fish and to reduce the need to set two sizes of nets.
I. Sampling Effort
A. Units of Effort
27 1. Each net per night equals 1 net night effort.
2. Minimum effort will be 2 net nights per lake.
B. Sample Period
1. Nets will be fished from before sunset to after sunrise and run within 24 hours of the time the nets were set.
II. Collection Frequency
A. Standard test-netting data will be collected each Fall between October 1 and November 15.
1. Additional supplemental netting for bluegill and crappie may be conducted from April 1 to May 31.
2. Spawning walleye can be collected from March 15 to April 15.
B. Net Placement
1. Set perpendicular to the shore with the frame in an upright position. If sets are made with the frame exposed above the water line, wave action may cause the trap to roll over.
2. Sampling sites should be randomly selected from the grids for each lake (Appendix II) that have been determined to be appropriate for trap nets.
a. Identify samples collected with both a grid number and with GPS latitude and longitude readings
b. Some grids may be unsuitable for sampling with this gear due to physical changes at the lake, such as water level fluctuations. In this case, selection should be randomly made from grids where suitable conditions exist
C. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Electrofishing (Blue Catfish option) Supplemental
Blue catfish have traditionally been sampled using various gill netting equipment. Electrofishing is an alternative that can be used to further evaluate blue catfish populations. Buckmeier and Schlechte (2009) reported that electrofishing collected representative samples for blue catfish from 250mm to 850mm. Individuals <250mm were under represented. The technique uses electrofishing equipment with low pulse frequency and low amperage capability in a stationary position or while the boat is slowly moving. Fish collection is primarily by a chase boat(s).
I. Operations 28 A. Direct Current (DC)
B. Amperes = 3 to 4
C. Electrofishing pulse rate = 15
D. In addition to the electrofishing boat, a chase boat is used. Two chase boats may be necessary to collect all blue catfish in some circumstances. Regardless, the number of chase boats utilized should be constant from year to year. The chase boat(s) is used to collect specimens that could surface in a 200 foot radius of the electrofishing unit.
II. Effort
A. Biologist should select a number of sample sites that is appropriate for the acreage and abundance of blue catfish at the impoundment. Mid-lake reaches along the main river channel should be primary locations.
B. A stationary electrofishing boat is operated with an energized field for five (5) minutes at each standardized sampling site.
III. Collecting and Reporting
A. Samples should be collected in mid July.
B. Samples should be processed site specifically.
C. CPUE is measured in terms of fish per 5 minutes of energized field time at each location.
D. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Electrofishing (Shad option) Supplemental
In Kansas, YOY gizzard shad have traditionally been sampled by shoreline seining. Electrofishing is an alternative that may be particularly useful wherever fluctuations of water levels limit the availability of suitable seining sites. Electrofishing for shad tends to produce results that are comparable to those produced by seining. While electrofishing works well for shad, sampling of other species might be more effectively accomplished by seining.
I. Operations
A. Direct Current (DC) is preferred
II. Effort
A. A minimum of 10 standard sites should be established per impoundment
B. Each site should be sampled for 0.1 hour of energized field time. The number of dipper(s) and shocker boom anodes should be consistent to 29 maintain data continuity from year to year. The dipper should be instructed to operate the foot switch and dip net to collect as many YOY shad as possible during the time allotted per site.
C. Collecting and Reporting
1. Samples should be collected in August with other months optional.
2. Samples should be processed site specifically with shad measured in 10mm length groups.
3. CPUE is measured in terms of fish per 0.1 hour of energized field time.
4. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Electrofishing (Flathead option) Supplemental
Flathead catfish have traditionally been sampled using various gill netting equipment. Electrofishing is an alternative that can be used to further evaluate flathead populations. This electrofishing option is experimental but has shown promise as a sampling technique for flathead and blue catfish, but not for channel catfish. The technique uses electrofishing equipment with low pulse frequency and low amperage capability in a stationary position or while the boat is slowly moving. Fish collection is assisted by a chase boat. In addition, an observer has been used to further evaluate size and abundance of flathead catfish that are not collected.
I. Operations
A. Direct Current (DC) is preferred
B. Amperes = 3 to 4
C. Electrofishing pulse rate = 15
D. In addition to the electrofishing boat, a chase boat is used. This boat is used to collect specimens that could surface in a 100 to 200 foot radius of the electrofishing unit.
E. An occupant of the electrofishing boat can be assigned as an observer.
1. This individual should be assigned no other duties while the sample is being collected.
2. The observer will provide a visual evaluation of the abundance and quality of flathead not captured during the sampling effort.
II. Effort
30 A. Biologist should select a number of sample sites that is appropriate for the acreage and abundance of flathead at the impoundment.
B. A stationary electrofishing boat is operated with an energized field for three (3) minutes at each standardized sampling site.
III. Collecting and Reporting
A. Samples should be collected in June.
B. Samples should be processed site specifically.
C. CPUE is measured in terms of fish per 3 minute of energized field time at each location.
D. Length and weight of fish collected will be entered in PC ADAS at the field level and electronically uploaded for addition to the archive.
Baited Hoop Nets (Tandem)-Supplemental
Traditionally, channel catfish have been sampled in Kansas small impoundments using various types of gill netting equipment. The use of baited hoop nets that are rigged in tandem has been shown to be an effective alternative to gill nets (Michaletz and Sullivan 2001, Colombo et al. 2007). Advantages of hoop nets include: reduced mortality; fewer individuals of nontarget species being collected and the ability to sample a variety of sizes with a single gear type.
I. Effort
A. Each tandem hoop net series (HNS) compose one unit of effort
1. Effort (HNS) will be dependant upon the size of each water body to be sampled.
a. minimum effort should be 2 HNS
B. Increased effort will result in more reliable length-frequency data. Additional sampling units of effort would be required for research and special projects to attain a higher confidence level of data.
1. Although each hoop net series consists of three hoop nets joined together with bridles, the combined catch of the three nets equal one “unit of effort”.
2. Each net series will be fished for a period of three nights
a. set before sunset (day 0)
b. run after sunrise (day 3)
II. Frequency of Collection 31 A. Standard hoop net sampling will be done between July and September
III. Collection
A. Sample Sites
1. Sampling sites should be randomly selected from the grids for each lake (Appendix II) that have been determined to be appropriate for hoop nets.
a. Identify samples collected with a grid number
b. Some grids may be unsuitable for sampling with this gear due to physical changes at the lake, such as water level fluctuations. In this case, selection should be randomly made from grids where suitable conditions exist.
B. Net Placement
1. Nets are set parallel to the shoreline
2. Water depth should be 1 to 4 meters (3 to 12 ft)
a. To avoid anoxic water
i. to reduce fish mortality
ii. to increase catches
b. Steeply sloping bottoms should be avoided
i. to prevent nets from collapsing
ii. to prevent nets from sliding into deeper water
3. An anchor with flukes that will dig into the substrate should be attached to the cod end of the rear net
a. allows the series to be stretched tight
4. Additional weights may be needed to keep the series from collapsing or moving
a. between the middle and front net
b. to bridle on the front net
5. Each net in the series is baited
a. with approximately 4 kg of bait. 32 III. Reporting
A. Length and weight of fish will be entered into PC ADAS at the field level and electronically uploaded for addition in the archive.
SAMPLING SPECIFIC SPECIES
Family Centrarchidae
I. Black Bass
A. Species
1. Largemouth Bass - Micropterus salmoides 2. Spotted Bass - Micropterus punctulatus 3. Smallmouth Bass - Micropterus dolomieui
B. Sampling
1. Electrofishing 2. All other gears (for supplemental data only)
C. Sampling Period
1. Spring Spawning Period - May 1 to June 1 or water temperatures of 60 to 70 degrees Fahrenheit
2. Fall electrofishing (supplemental)
II. Crappie
A. Species
1. White Crappie - Pomoxis annularis 2. Black Crappie - Pomoxis nigromaculatus
B. Sampling Techniques
1. Trap Nets - A-inch mesh
2. Standard core-mesh Gill Nets - (to supplement trap net data)
C. Sampling Period
1. Fall Standard Netting 2. Spring Spawning - April to May (supplemental)
III. Bluegill - Lepomis macrochirus
A. Sampling Techniques 33 1. Trap Nets - '/2-inch mesh 2. Electrofishing (for supplemental data)
B. Sampling Period
1. Standard Fall sampling (Oct. - Nov.) 2. Spring Spawning period (May-June) (for supplemental data)
IV. Others
A. Species
1. Green Sunfish - Lepomis Cyanellus 2. Orangespotted Sunfish - Lepomis humilis 3. Longear Sunfish - Lepomis megalotis 4. Redear Sunfish - Lepomis microlophus 5. Rock Bass - Ambloplites rupestris
B. Sampling Techniques
1. Trap Nets - /-inch mesh 2. Electrofishing (for supplemental data)
C. Sampling Period
1. Standard Fall sampling (Oct. - Nov.) 2. Spring Spawning period (May-June) (for supplemental data)
Family Ictaluridae
I. Catfish
A. Species
1. Channel Catfish - Ictalurus punctatus 2. Flathead Catfish - Pylodictis olivaris 3. Blue Catfish - Ictalurus furcatus
B. Sampling Techniques
1. Gill Nets - standard core-mesh
a. If supplemental data is needed for smaller or larger fish than normally targeted using core-mesh nets, additional gill nets with different mesh sizes can be fished independently (i.e., separate nets)
2. Baited Hoop Nets (Tandem) - Supplemental
34 3. Electrofishing (supplemental for flathead and blue catfish) SEE INFORMATION ABOVE
C. Sampling Period
1. Standard Fall test-netting (Oct.-Nov.) 2. Post Spawning period (July - September)
a. if using baited hoop nets
II. Others
A. Species
1. Black Bullhead - Ameiurus melas 2. Yellow Bullhead - Ameiurus natalis
B. These species are to be sampled during the standard test netting
C. Sample Period
1. Standard test-netting (Oct. - Nov.)
Family Percidae
I. Species
1. Walleye - Sander vitreus 2. Sauger - Sander canadensis 3. Saugeye - S. vitreus x S. canadensis
A. Sampling techniques
1. Gill nets - Standard core-mesh 2. Trap Nets (for Spring egg collection efforts and supplemental data) 3. Electrofishing (for Fall YOY indices)
II. Sampling Period
A. Standard test-netting
1. October - November 2 . for general population data
B. Spring egg collection
1. mid-March thru mid-April 2 . 1-inch traps may be substituted for A-inch mesh traps
35 C. Fall Electrofishing
1. for supplemental YOY indices 2. at water temperatures <65° F.
Other Species
I. Gizzard Shad - Dorosoma cepedianum
A. Sampling Techniques
1. Seine - (YOY) 2. Fry Trawl - (larval YOY) 3. Gill Net - (subadults - adults) 4. Electrofishing - (subadults - spawning adults) 5. Rotenone sampling - (all ages)
B. Sampling Period
1. Standard Fall test-netting (general population parameters) 2. May - June (fry trawl for larval assessment) 3. July - August (electrofishing or seining to assess YOY production)
a. supplemental b. if prey management has been targeted
II. Morone spp.
A. Species
1. White Bass - Morone chrysops 2. Striped Bass - Morone saxatilis 3. Wiper - M. chrysops x M. saxatilis
B. Sampling Techniques
1. Standard core-mesh gill nets
2. Large mesh gill nets (>4”) may be necessary for supplemental sampling of populations with adult striped bass or large wipers
3. Trap nets (To supplement core-mesh gill net data)
4. Seining for YOY assessment
C. Sampling Period
1. Standard Fall sample (Oct. - Nov.)
2. Fall electrofishing (for supplemental YOY data)
36 III. Grass Carp - Ctenopharyngodon idella
A. Sampling Techniques (for small lakes)
1. Standard core-mesh gill net plus a 4-inch gill net
2. Electrofishing in feeding areas
3. Shoreline Seining (50ft. bag seine) in feeding areas
B. Sampling Period
1. Standard Fall sample (Oct. - Nov.)
3. Others - when convenient to capture.
CONFIDENCE INTERVALS
Catch rates of fish are used by fisheries biologists to estimate relative abundance, which are assumed to be proportional to population density. The high variability of catch rates among sampling sites can severely reduce the value of catch data reduce the value of catch data. Confidence intervals (CI) for mean catch should be calculated so that the quality of estimates can be assessed.
Confidence intervals are easily calculated using the formula:
CI = Mean ± t(df,sl) x SE where MEAN = mean catch; t(df,sl) = critical value from the Student’s t-distribution df (degrees of freedom (n-1)) and sl significance level (Table 1)); and SE = standard error of the mean.
The t-distribution values can be looked up in Table 1. For example, 5 trap net samples would have 5 - 1 = 4 degrees of freedom. Find df = 4 in the left-hand column of Table 1. By reading across this line to the 0.20 significance level column (for 80% CI), you should find a t-distribution value of 1.533; at the 0.50 level (95% CI) the t-distribution value is 2.2.776.
Standard Error can be calculated as follows:
SE= s V n where s is the sample standard deviation , n is the sample size,.
37 For the above example, assume you caught in the five trap nets. The SE for this data is calculated as follows:
NET Catch (X) X2 1 10 100 2 12 144 3 15 225 4 7 49 5 9 81 IX = 53 IX 2 = 599 n=5
Sample sum of squares (ss) = IX2 - (IX )2 = 599 - 2809 = 37.2 n 5
Population variance (s2) = ss = 37.2 = 9.3 n - 1 4 '
Sample variance or Standard Deviation (s) = Vs2 = V9.3 = 3.05
Standard Error = SE = s = 3.05 = 1.364 V n 2.236
The mean, 80% and 95% Cl’s are calculated as follows:
Mean (X) = I X = 53_ = 10.6 n 5 _ 80% CI = X ± (1.533 x SE) = 10.6 ± 2.1
95% CI = X ± (2.776 x SE) = 10.6 ± 3.8
Table 1. Critical values for Student’s t-distribution (Sokal and Rohlf, 1973)
Degrees of Significance Level Freedom (df) 0.20 0.05
1 3.078 12.706 2 1.886 4.303 3 1.638 3.182 4 1.533 2.776 5 1.476 2.571
6 1.440 2.447 7 1.415 2.365 8 1.397 2.306 9 1.383 2.262 10 1.372 2.228
38 11 1.363 2.201 12 1.356 2.179 13 1.350 2.160 14 1.345 2.145 15 1.341 2.131
16 1.337 2.120 17 1.333 2.110 18 1.330 2.101 19 1.328 2.093 20 1.325 2.086
21 1.323 2.080 22 1.321 2.074 23 1.319 2.069 24 1.318 2.064 25 1.316 2.060
26 1.315 2.056 27 1.314 2.052 28 1.313 2.048 29 1.311 2.045 30 1.310 2.042
40 1.303 2.021 60 1.296 2.000 120 1.286 1.980
1.282 1.960
Coefficient of Variation
In probability theory and statistics, the coefficient of variation (Cy) is a normalized measure of dispersion of a probability distribution. It is defined as the ratio of the standard deviation o to the mean p:
o Cv = ___ x 100 P
This is only defined for non-zero mean, and is most useful for variables that are always positive. It is also known as unitized risk.
The coefficient of variation should only be computed for data measured on a ratio scale. As an example, if a group of lengths are analyzed, the standard deviation does not depend on whether the measurements are recorded in millimeters or inches. However the mean length of the data set would be different in each scale and thus the coefficient of variation would be different. So the coefficient of variation does not have any meaning for data on an interval scale.
39 Coefficient of Variation of the Mean (Cv X)
The precision with which fish density is measured can be estimated as the coefficient of variation of the mean (Cv J? = SE/.?) (Cyr et al. 1992). This should not to be confused with the coefficient of variance of samples (see above). The coefficient of variation of the mean is a function of the average number of fish found per sample (.?). inter-sample variance (s2), and the number of samples collected (n ) .
Because Cv % utilizes the number of samples in the calculation, it is typically easier to achieve a target coefficient value using this method than by using the more traditional coefficient of variation of samples method. For this reason, KDWP will use Cv to determine when a sufficient population sample has been collected. The target Cv X value for most sampling efforts will be 0.25. In unusual circumstances or when sampling mortality is considered a overriding factor, the target Cv % value may be increased. Changes in target values must have prior approval by a Fisheries Regional Supervisor.
An Excel spreadsheet that will calculate both the coefficient of variation of samples and coefficient of variation of means has been developed and is available on the KDWP Fisheries & Wildlife Division’s intranet site: http://fw1.wp.state.ks.us/fw1/FW1-Home/Fisheries/Web-Applications/Sample-Covariance-Worksheet2
40 REFERENCES
Anderson, R.O., and R.M. Neumann. 1996. Length, weight, and associated structural indices. Pages 447 482 in Murphy, B.R. and D.W. Willis, editors. Fisheries techniques, 2nd Edition. American Fisheries Society, Bethesda, Maryland.
Bonar, S. A., W. A. Hubert, and D. W. Willis, editors. 2009. Standard methods for sampling North American freshwater fishes. American Fisheries Society, Bethesda, Maryland.
Bonn, E.W. 1969. Use of a trawl for sampling freshwater impoundments in Texas. Proceedings of the Annual Conference Southeastern Association of Game and Fish Commissioners 22:354-361.
Borkholder, B.D., and B. G. Parsons. 2001. Relationship between electrofishing catch rates of age-0 walleyes and water temperature in Minnesota lakes. North American Journal of Fisheries Management 21:318-325.
Buckmeier, D. L. and J. W. Schlechte. 2009. Capture efficiency and size selectivity of channel catfish and blue catfish sampling gears. North American Journal of Fisheries Management 29:404-416.
Cyr H., J.A. Downing, S. Lalonde, S. B. Baines, and M. L. Pace. 1992. Sampling larval fish populations: choice of sample number and size. Transactions of the American Fisheries Society 121:356-368.
Colombo, R. E., Q. E. Phelps, J. E. Garvey, and R. C. Heidinger. 2007. Gear-specific population demographics of channel catfish in a large Midwestern river. North American Journal of Fisheries Management 28: 241-246.
Davies, W.D., and W.L. Shelton. 1983. Sampling with toxicants. Pages 199-218 in L.A. Nielsen and D.L. Johnson, editors. Fisheries techniques. American Fisheries Society, Bethesda, Maryland.
Dauwalter, D. C., W. L. Fisher, R. A. Marston, and D. K. Splinter. 2004. Random selection of stream sites: an important step in fluvial geomorphic and fishery surveys. Pages 30-33 in J. R. Copeland, F. Fiss, P. E. Balkenbush, and C. S. Thomason, editors. Warmwater streams symposium II. Available: www.sdafs.org/wwstreams/wwsc1.htm (June 2007).
Gabelhouse, D.W., Jr. 1984. A length-categorization system to assess fish stocks. North American Journal of Fisheries Management 4:273-285.
Gustafson, K.A. 1986. Approximating confidence intervals for fish stock-density index calculations. Fisheries I & D 86-9, Kansas Fish and Game Commission, Pratt.
Hamley, J.M. 1975. Review of gill net selectivity. Journal of the Fisheries Research Board of Canada 32:1943-1969.
Hartmann, R.F. 1980. Statewide creel census. Kansas Fish and Game Commission, Federal Aid Project F-15-R, Final Report for Segments 13, 15, and 16, Pratt.
Hartmann, R.F. and T.D. Mosher. 1978. A manual for the use of the aquatic data analysis system (ADAS) and fisheries data system (FDS). Kansas Fish and Game Commission, Pratt.
Hubbard, W. D., and L. E. Miranda. 1988. Competence of random electrofishing sampling in assessment of structural indices. Proceedings of the Annual Conference Southeastern Association of Fish and Wildlife Agencies 40(1986): 79-84.
41 Jenkins, R.M. and D.I. Morais. 1978. Prey-predator relations in the predator-stocking-evaluation reservoirs. Proceedings of the Annual Conference Southeastern Association of Fish and Wildlife Agencies 30:141-157.
Marteney, R. E. and T. D. Mosher. 2004. Fish survey techniques for small lakes and reservoirs. Kansas Department of Wildlife and Parks. Pratt, Kansas.
Michaletz, P.H. and K.P. Sullivan. 2001. Sampling channel catfish with tandem hoop nets in small impoundments. North American Journal of Fisheries Management 22:870-878.
Miranda, L. E. 2005. Refining boat electrofishing equipment to improve consistency and reduce harm to fish. North American Journal of Fisheries Management 25:605-618.
Miranda, L. E. and C. R. Dolan. 2003. Test of a power transfer model for standardized electrofishing. Transactions of the American Fisheries Society 132:1179-1185.
Miranda, L. E. and C. R. Dolan. 2004. Electrofishing power requirements in relation to duty cycle. North American Journal of Fisheries Management 24:55-62.
Miranda, L.E., W.D. Holland, S. Sangare, and T. Holman. 1996. Optimizing electrofishing sample duration for estimating relative abundance of largemouth bass in reservoirs. North American Journal of Fisheries Management 16:324-331.
Miranda, L. E. and A. B. Spencer. 2005 Understanding the output of a Smith-Root GPP electrofisher. North American Journal of Fisheries Management 25:848-852.
Miranda, L. E. and M. Kratochvil. 2008. Boat electrofishing relative to anode arrangement. Transactions of the American Fisheries Society 137:1358-1362.
Serns, S.L. 1982. Relationship of walleye fingerling density and electrofishing catch per effort in northern Wisconsin lakes. North American Journal of Fisheries Management 2:38-44.
Sokal, R.R. and F.J. Rohlf. 1973. Introduction to biostatistics. W.H. Freeman and Company, San Francisco, California.
Swingle, H.S. 1956. Appraisal of methods of fish population study - Part IV, Determination of balance in farm fish ponds. Transactions of the North American Wildlife Conference 21:298-322.
Wilde, G. R., and W. L. Fisher. 1996. Reservoir fisheries sampling and experimental design. Pages 397 409 in L. E. Miranda and D. R. DeVries, editors. Multidimensional approaches to reservoir fisheries management. American Fisheries Society, Symposium 16, Bethesda, Maryland.
Willis, D.W. 1985. Revised correction factors for adjustment of white bass gill-netting data based on mesh-size efficiency. Kansas Fish and Game Commission, Pratt.
Wills, D.W. and B.R. Murphy. 1996. Sampling considerations. Pages 8-14 in Murphy, B.R. and D.W. Willis, editors. Fisheries techniques, 2nd Edition. American Fisheries Society, Bethesda, Maryland.
Willis, D.W., K.D. McCloskey, and D.W. Gabelhouse, Jr. 1985. Calculation of stock density indices based on adjustments for efficiency of gill-net mesh size. North American Journal of Fisheries Management 5:126-137.
42 APPENDIX 1. Gear used to collect most commonly sampled fishes in Kansas impoundments. (P = primary; S = supplemental)
Gill Trap Hoop Electro Creel Species Nets Nets Nets fishing Seining Survey
Walleye - Sander vitreus P S S* S* S
Sauger - Sander canadensis P S S* S* S
Saugeye - S. vitreus x S. canadensis P S S* S* S
White Bass - Morone chrysops P S S* S
Striped Bass - Morone saxatilis P S
Wiper - M. chrysops x M. saxatilis P S S* S
Channel Catfish - Ictalurus punctatus P S S* S
Flathead Catfish - Pylodictis olivaris P S S* S
Blue Catfish - Ictalurus furcatus P S S* S
White Crappie - Pomoxis annularis P* * S S
Black Crappie - Pomoxis nigromaculatus P** S S
Bluegill - Lepomis macrochirus P S S* S
Largemouth Bass - Micropterus salmoides P S* S
Spotted Bass - Micropterus punctulatus P S* S
Smallmouth Bass - Micropterus dolomieui P S* S
Bigmouth Buffalo - Ictiobus cyprinellus P S* S
Smallmouth Buffalo - Ictiobus bubalus P S* S
River Carpsucker - Carpiodes carpio P S* S
Common Carp - Cyprinus carpio P S* S
Freshwater Drum - Aplodinotus grunniens P S* S
Gizzard Shad - Dorosoma cepedianum P S** S*
Minnows (Family Cyprinidae) P
Darters (Family Percidae) P
* = young-of year ** = adults and young-of-year
43