Metadata

Protocol Title:  Electrofishing

Protocol Creator(s)

• Name: Dr. Jennifer Rehage 

Publication Date:  2004-01-01

Abstract
Sampling is conducted at 15 mangrove creeks in two drainages: Rookery Branch and the North, Roberts, and Watson rivers. Electrofishing is used to target large-bodied predatory species. At each creek, we systematically sample, three 100 meter long sections of creek bank by electrofishing (0-100m, 200-300m, and 400-500m). Each electrofishing bout lasts five minutes (pedal time). Electrofishing is an effective method for sampling large fishes in freshwater habitats, and eletrofishing catch per unit effort (CPUE) provides a reliable index of fish abundance. For all bouts, electrofishing power is standardized to 1500 watts according to the ambient temperature and conductivity conditions. Because creek width is considerably greater than the electric field generated by the electrofisher, a left or right bank was randomly selected for each bout. Folling USGS-NAWQA guidelines, all electrofishing is conducted using intermittent application of electrical current to prevent fish from fleeing deep beneath the mangroves. All fish captured are placed in a holding tank, identified, measured (to the nearest 1-mm standard or total length), weighed (if necessary), and released after full recovery. We measure mass of those species for wich we do not have reliable length-mass regression equations with which to estimate mass-this procedure results in less handling of fishes and reduces stress on the specimens. Only non-indigenous species are saved and preserved in 10 percent formalin to be returned to the laboratory for processing. Although electrofishing typically targets large fish species, we routinely capture specimens as small as 5-cm standard length (SL). During each sampling event, we use a YSI 85 unit to record physico-chemical parameters (water temperature, specific conductance/salinity, and dissolved oxygen) at the beginning of each electrofishing bout. Water clarity and bottom type are measured with a measuring stick and turbidity with an electronic turbidity meter.
Sampling is conducted at 15 mangrove creeks in two drainages: Rookery Branch and the North, Roberts, and Watson rivers. Electrofishing is used to target large-bodied predatory species. At each creek, we systematically sample, three 100 meter long sections of creek bank by electrofishing (0-100m, 200-300m, and 400-500m). Each electrofishing bout lasts five minutes (pedal time). Electrofishing is an effective method for sampling large fishes in freshwater habitats, and eletrofishing catch per unit effort (CPUE) provides a reliable index of fish abundance. For all bouts, electrofishing power is standardized to 1500 watts according to the ambient temperature and conductivity conditions. Because creek width is considerably greater than the electric field generated by the electrofisher, a left or right bank was randomly selected for each bout. Folling USGS-NAWQA guidelines, all electrofishing is conducted using intermittent application of electrical current to prevent fish from fleeing deep beneath the mangroves. All fish captured are placed in a holding tank, identified, measured (to the nearest 1-mm standard or total length), weighed (if necessary), and released after full recovery. We measure mass of those species for wich we do not have reliable length-mass regression equations with which to estimate mass-this procedure results in less handling of fishes and reduces stress on the specimens. Only non-indigenous species are saved and preserved in 10 percent formalin to be returned to the laboratory for processing. Although electrofishing typically targets large fish species, we routinely capture specimens as small as 5-cm standard length (SL). During each sampling event, we use a YSI 85 unit to record physico-chemical parameters (water temperature, specific conductance/salinity, and dissolved oxygen) at the beginning of each electrofishing bout. Water clarity and bottom type are measured with a measuring stick and turbidity with an electronic turbidity meter.
Sampling is conducted at 15 mangrove creeks in two drainages: Rookery Branch and the North, Roberts, and Watson rivers. Electrofishing is used to target large-bodied predatory species. At each creek, we systematically sample, three 100 meter long sections of creek bank by electrofishing (0-100m, 200-300m, and 400-500m). Each electrofishing bout lasts five minutes (pedal time). Electrofishing is an effective method for sampling large fishes in freshwater habitats, and eletrofishing catch per unit effort (CPUE) provides a reliable index of fish abundance. For all bouts, electrofishing power is standardized to 1500 watts according to the ambient temperature and conductivity conditions. Because creek width is considerably greater than the electric field generated by the electrofisher, a left or right bank was randomly selected for each bout. Folling USGS-NAWQA guidelines, all electrofishing is conducted using intermittent application of electrical current to prevent fish from fleeing deep beneath the mangroves. All fish captured are placed in a holding tank, identified, measured (to the nearest 1-mm standard or total length), weighed (if necessary), and released after full recovery. We measure mass of those species for wich we do not have reliable length-mass regression equations with which to estimate mass-this procedure results in less handling of fishes and reduces stress on the specimens. Only non-indigenous species are saved and preserved in 10 percent formalin to be returned to the laboratory for processing. Although electrofishing typically targets large fish species, we routinely capture specimens as small as 5-cm standard length (SL). During each sampling event, we use a YSI 85 unit to record physico-chemical parameters (water temperature, specific conductance/salinity, and dissolved oxygen) at the beginning of each electrofishing bout. Water clarity and bottom type are measured with a measuring stick and turbidity with an electronic turbidity meter.

Keywords
Electrofishing, fish capture
Procedural Steps
Apply electric current to sampling area
net immobilized fish
place fish into a water tank on boat