Published:
N/A
Originator:
George Earl Trice IV, Matthew Balazik
Associated with:
Invasive Catfish Workgroup

The goal of the project was to design a more effective way to harvest invasive catfish (predominantly blue catfish, Ictalurus furcatus) in Virginia waters stunned by low-frequency electrofishing (LFE). LFE was conducted from May 18, 2015 to October 6, 2015; however, no weight was harvested on October 6 when water temperatures were 19oC . None of the data collected from the October 6 trip was used for catch statistics. Seventy-five trips were made during the LFE season; 37 in the James River and 38 in the Pamunkey River (Figure 1). The last day enough blue catfish (BCF) were susceptible to make commercial harvest worthwhile was September 29, 2015 when water temperatures were 23oC. In 2014 only large hooped (handle length about 2.5m long with a 0.4m2 net opening) were used to collect stunned fish. During the 2014 study 155,161lbs of catfish were harvested electrofishing for 5430 minutes resulting in a catch-per-unit-effort (CPUE) of 28lbs per minute. In 2015 a total of 334,680lbs of catfish were landed electrofishing for 12850 minutes resulting in a CPUE of 26lbs per minute (Figure 2, Table 1). Three different new harvest techniques methods were attempted to increase the harvest efficacy of invasive BCF compared to regular dip netting: 1) a modified butterfly skimmer (Figure 3), 2) pulling a hoop net along the side of the boat, 3) dragging a surface trawl behind the boat (Figure 4). All three techniques were compared to a chase boat that utilized simple dip nets. The chase boat using dip nets harvested significantly more weight than the new techniques (Table 2). One modification that substantially helped harvest of small fish was using dip nets with smaller openings (0.24m2) and handles 3.5m long. The smaller nets had a wire mesh which allowed fish to be dumped out quicker without hanging in the mesh.

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