Already in the 19th century Sabaneev (1960) reported that piscivorous visually guided zanders, Stizostedion lucioperca, which eat only live food can nonetheless be caught on dead fish cut into stripes with the skin and silver scale. Like other visually guided predatory fish, namely pike, Esox lucius, and perch, Perca fluviatilis, zanders never eat decaying fish. According to the modern knowledge, zanders could respond in addition to visual cues to alarm pheromone that released in the water from the injured skin of fish or from dead fish without injuring their skin (Malyukina et al., 1980).

Indeed, dead fish in trolling and other rigs may be used to fish big pike and zander (Sabaneev, 1960).

In the undirect winter experiments carried out in the USA by Wisenden & Thiel (2001), predatory fish active in cold season such as pike, E. lucius, walleye, S. vitreum, largemouth bass, Micropterus salmoides, and yellow perch, P. flavescens, colud be attracted by the skin extract of fathead minnow, Pimephales promelas (Cyprinidae).

In the direct field experiments (Dnipro river in Ukraine, in June) described below, we found that S. lucioperca could be attracted by alarm pheromone of roach, Rutilus ruitlus.

Chemical stimulus of one type was prepared by squashing 30 g of roach skin together with the scale in the rough clay mortar and diluted with the 0,3 liter of river water, without further filtration. Chemical stimulus of another type was prepared of 30 g of roach flesh without skin in the foregoing way (according to Malyukina et al., 1980, standard extract of fish skin contains 1g of skin per 1 liter of water).

To compare both chemical stimuli, artificial soft lures made of high quality white foam rubber were used. Lures were in the form of stripes (0,5 x 0,5 x 5,0 cm) attached at one end to the single hooks (VMC live bait hooks #1/0, short shank). For more buoyancy, one white styrofoam olive was dressed similar to sabiki on the line leader in front of each lure.

In the field, two units of the typical feeder rods with reels, main lines, simple sinkers and two line leaders, 30 and 40 cm length, with the attached lures were used. In one rig, lures attached to 30 and 40 cm leaders was soaked with the skin and flesh extracts, respectively, vice versa in another rig.

Lures of both types were compared in the typical zander location with the depth of 2,0- 2,5 m at the distance of 15-20 meters from the shore, with the middle flow. Tests were carried out during two nights from 10⁰⁰ of evening until 12⁰⁰ of midnight, skin and flesh extracts in rubber bodies of lures were resoaked every thirty minutes.

In total, within two nights 21 bites were obtained. Potential predators, in addition to zander, were large individuals of chub, Leuciscus cephalus, ide, L. idus, and wels catfish, Silurus glanis, all with the nocturnal type of feeding activity. Among potential predators, 9 individuals of zander (from 0,8 to 1,2 kg) were caugh, all for lures soaked with the skin extract (sign test, n = 9, z = 9, p < 0,01). Also, single 3 kg wels was caught for the same lure.

These data show the preference of zanders to alarm pheromone of cyprinid fish. According to Valentinčič (2004), for wild zanders an odor of the fish flech extract must be indifferent.

Basic References

Malyukina G.A., Kasumyan A.O., Marusov E.A. 1980. Significance of olfaction in fish behaviour. Sensory systems: olfaction and gustation, 30-44

Sabaneev L.P. 1960. Life and fishing of freshwater fish. Prepared on the 3rd edition of 1911. Agricultural Literature State Publishing, Ukrainian SSR, Kyiv

Valentinčič T. 2004. Taste and olfactory stimuli and behavior in fishes. The senses of fish: Adaptations for the reception of natural stimuli. 90-108

Wisenden B.D., Thiel T.A. 2001. Field verification of predator attraction to minnow alarm substance. Journal of Chemical Ecology 28, 417-422