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On the attractivity of earthworms, Eisenia foetida, in the capacity of fishing bait

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 set in evening (about 10:00 pm, in June) and checked at dawn to avoid catching fish with the day type of feeding activity.

The number of fish caught in the pair traps with the compared odors are shown for clarity in the Table 1. According to Wilcoxon sign-rank test (n = 10, Tfact < T standard, P < 0,01), spined loach ignored an odor of earthworms, E. foetida, at the high level of reliability.

In the daytime, the same minnow traps allow to catch juvenile roach, Rutilus rutilus, and other cyprinid fish chiefly with the day type of feeding activity. In all these tests, naïve fish preferred an odor of bloodworms, C. plumosus, over an unknown and unusual odor of earthworms, E. foetida.

For comparison (Fiore et al., 2004), predatory flatworms, Bipalium adventitium, are less successful at preying on E. foetida than on Lumbricus rubellus and L. terrestris with some aversion to the secretions of E. fetida.

So, use of the foregoing worms as an accessible fishing bait needs prebaiting. Apparently, in those fishing localities where anglers use these worms regularly fish are familiar with this bait.

Basic References

Fiore C., Tull J.L., Zehner S., Ducey P.K. 2004. Tracking and predation on earthworms by the invasive terrestrial planarian Bipalium adventitium (Tricladida, Platyhelminthes). Behavioural Processes 67, 327-334

Kostecka J., Pączka G. 2006. Possible use of earthworm Eisenia fetida (Sav.) biomass for breeding aquarium fish. European Journal of Soil Biology 42, S231-S233

Marszał L., Grzybkowska M., Przybylski M., Valladold M. 2003. Feeding activity of spined loach Cobitis Sp. in Lake Lucień, Poland. Folia biologica (Kraków) 51, S159-S165

Ortega C.M.F., Reyes O.A.L., Mendoza M.G. 1996. Chemical composition of earthworm (Eisenia fetida and Lumbricus rubellus) silages. Archivos Latinoamericanos de Nutrición 46, 325-328

Reinecke A.J., Hayes J.P., Cilliers S.C. 1991. Protein quality  of three different species of earthrvorms. South African Journal of Animal Science 21, 99-103

Robotman P.W.J. 1977. Feeding habits and diet in two populations of spined loach, Cobitis taenia (L.). Freshwater Biology 7, 469-477

Stafford E.A., Tacon A.G.J. 1985. The nutritional evaluation of dried earthworm meal (Eisenia foetida, Savigny, 1826) included at low levels in production diets for rainbow trout, Salmo gairdneri Richardson. Aquaculture Research 16, 213-222

Category: Baits | Views: 1634 | Added by: nickyurchenko | Tags: earthworms, Cobitis taenia, odors, spined loach, Eisenia foetida | Rating: 0.0/0





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