Earthworms, Eisenia foetida, are widely used as an accessible bait for many fish. Fishing practice shows, however, that these worms are not as attractive to fish as it is commonly believed.

The scientific term foetida references the well known fact that these worms use the yelowish stinky secretion for self-defense. If the worms are handled roughly, they emit an unpleasure odor designed to drive away predators. This stinky secretion can also be used to distinguish E. foetida from some close relative worms that look in the similar ways.

In addition, there are problems with the palatability and nutritive value of these worms as food for fish in aquaculture in comparison with other earthworm species (Stafford & Tacon, 1985; Reinecke et al., 1991; Ortega et al., 1996; Kostecka & Pączka, 2006). The aim of the foregoing research was to find the strong arguments advocating an idea to use these worms as an available protein source to fish.

Fishing Practice

In the field experiments, we compared the attractivities of an odor of squashed live earthworms, E. foetida, that may be unfamiliar food to fish, and an odor of natural food. Spined loach, Cobitis taenia, were selected as an model fish due to their abundance in the research area, small size (usable for minnow traps) and the night type of feeding activity (Robotman, 1977; Marszał et al., 2003). Squashed live bloodworms, Chironomus plumosus, were used in the capacity of food that is closer to the natural diets of spined loach in the different habitats than terrestrial earthworms.

Spined loach, Cobitis taenia (powered by Lubomir Hlasek)

Experiments were carried out in the upper part of Kaniv’s reservoir, below Kyiv, in the summer season.

Fish were caught in the narrow ducts of 20-40 cm depth with the slightly muddy sandy bottom and few macrophytes like pondweeds. Because spined loach were small (4-6 cm), that is mean length for this species, simple minnow traps made of 6 liters transparent plastic bottles were used. When setting at the bottom, the necks of the traps were located at the distance of 20 cm from each other and submerged by half into the sand. After final trap setting, feeders with 3gr of squashed earthworms and, correspondingly, 3gr of squashed bloodworms were fell through the top holes in the pair traps. Traps were ... Read more »