New York State Canal System

Fish Assessment

§         Gear – 16' flat bottom, electroshocking boat.

§         Locations – In 2004, we are sampling at Tonawanda (Niagara River confluence), Rochester (Genesee River confluence), Fulton (Oswego River), Montezuma (Cayuga-Seneca Canal and Erie Canal), and Utica.

§         Sample Dates – May and September.

§         Procedure – Historic sample sites at each location are electroshocked for a targeted time of 500 seconds.  3-5 sites are sampled at each location. 

§         Fish data collected – Length, species.  New invasive fish are not released.

§         Other data collected – Water temperature, DO, air temperature, depth, secchi, plankton samples at each electrofishing locations.

§         This study seeks to strengthen baseline historic fish community information and search for new invasive species of fish and plankton that may be introduced.

This protocol uses three gear types:  gill nets, Fyke nets and electrofishing.

Electrofishing:

1) Electrofishing should be conducted with pulsed DC, high range 100-1000 volts, 120 cycles per second

2) Standardize power output of the electrofishing unit based on the conductivity of each lake (see Appendix C)

3)  Electrofish starting at each randomly chosen sampling point for 600 seconds as measured by the timer on the electrofishing unit.  Always record on data sheets the actual number of seconds shocked

4)  Electrofish in the same direction from the sampling point for all samples

5)  Electrofish pedal operations (continuous or intermittent) are at the discretion of the operator, and should be designed to capture the highest number of fish.  Use intermittent shocking when approaching structure such as beaver lodges, downed trees, docks and weed patches.  Stay off the pedal until close to structure, then hit the pedal.

6)  A minimum of two dippers and one driver should be in each electrofishing boat.  Dippers should go for everything, even young-of-year

7)  We have found that catch rates go down if you electrofish the same section over again.  Never cover the same section that you have electrofished over again

8)  Make sure that when fish are worked up, they are released back at the start of the section, and not near the end where they can stray into the next section to be electrofished again

9) Electrofish at night to have the highest catch rates.

This monitoring protocol calls for a combination of gear types, including electrofishing, hoop netting, Fyke netting and trawling. 

The electrofishing component of the protocol uses 5.5-m (18 ft) flat-bottomed aluminium boats powered by 45 to 110 hp outboard motors.  A pulsed De field is used at 60 Hz (uniform base power of 3,000 W).

Electrofishing is conducted in the daytime from one hour after sunrise to one hour before sunset.  Sampling runs have a duration of 15 minutes and are approximately 200 m long and 30 m wide.

See document for extensive technical descriptions of sampling technique.