Fishermen Advocates: Disclosing Forgery in Fishing Industries




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Freshwater percid (Percidae) fish can be divided into the two groups depending on type of their activity and sensory equipment. European perch, Perca fluviatilis, American yellow perch, Perca flavescens, and numerous American darters (Etheostoma) demonstrate the diurnal type of activity (first of all of the feeding activity), are visually guided fish and, thus, may be included in the first group.

In laboratory and natural conditions, both perches usually do not eat immobile as well as dead food and demonstrate relatively weak responses to food odors or their absence. According to Mirza et al. (2003), an aqueous brine shrimp (Artemia spp.) extract (5 g of frozen shrimp in 150 ml of distilled water for 1 hour) induces searching movements in P. flavescens. Both perches, however, do not go practically into the minnow traps baited with the animal lures (in contrast to cyprinid, cobitid and other fish).

In aquarium, blinded P. fluviatilis may find the pieces of earthworms using olfactory and gustatory systems (Wunder, 1927). But convergence of perch with brown trout, Salmo trutta, on sensory system utilization is incorrect.

Both species of euryhaline Percarina, Azov percarina, P. maeotica, and common percarina, P. demidoffi, use vision in day when hunting for zooplankton and lateral line system at night when hunting for preyfish (Kanaeva, 1956).

Roberts and Winn (1962) have tested utilization of the senses in feeding behavior of johnny darter, Etheostoma nigrum, using live worms (Tubifex), dead worms and crushed worm solutions. It is shown that darters prefer live worms and respond slightly to an olfactory stimulus. Daugherty et al. (1976) have studied responses of six species of darters (E. gracile, E. spectabile, E. whipplei, E. radiosum, E. collettei and E. punctulatum) to visual and olfactory cues of worms. It is revealed that olfactory cues (water from live Tubifex) alone are not sufficeint to stimulate complete feeding behaviour in darters, both in clear or muddy waters.

Fountain darter, Etheostoma fonticola, respond to live aquatic microinvertebrates and ignore immobile items (Shenck & Whiteside, 1977).

Darters or longperches of Percina genus are also diurnally active and feed on live macroinvertebrates (Greenberg, 1991). Percina are more mobile than Etheostoma and spent most time above the bottom.

Another group is formed by percids with the twilight or nocturnal type of feeding activity with the well developed chemosensory and lateral line systems. Three Europen zander ... Read more »

Category: Olfaction & Gustation | Views: 532 | Added by: nickyurchenko | Date: 2013-06-17

Microsmatic fish are represented by species in which the well developed visual system provides most of the behavioural responses in comparison with the less developed chemosensory system (Devitsina & Malyukina, 1977). Visually guided diurnal or twilight predators, like Northern pike, Esox lucius, and other Esocidae, on the one hand, and visually guided planktoneaters, like Black Sea black-striped pipefish, Syngnathus nigrolineatus, and other Syngnathidae, on the second hand, form this group of fish (e.g., Doroshenko, 2008). In general, the chemosensory system of microsmatic fish provides first of all their reproductive behaviour, spatial migration, partially anti-predator behaviour and is weak or indifferent in providing feeding responses.

Data for microsmatic fish are given by many authors (Hara, 1975; Devitsina, 1977; Devitsina & Malyukina, 1977; Doroshenko, 1981, 2008).

Pike & Musky

According to data received by Devitsyna & Malyukina (1977) in the electrophysiological experiments, the olfactory system of pike, E. lucius, responds only to conspecific sexual pheromones (gonad extracts), but does not respond to conspecific odors, pure water and feeding substances like fish blood or tissue extracts.

In the behavioural experiments with pike, Nilsson & Brönmark (1999) have found that the chemical cues from the foraging conspecifics render only minor effects upon the foraging individuals.

In feeding behaviour, musky, E. masquinongy, use mainly vision and lateral sensory systems (New et al., 2001).

Pike larvae decrease the frequency of their attacks on zooplankters and show other anti-predator responses to chemical cues of Eurasian perch, Perca fluviatilis (Lehtiniemi, 2005; Lehtiniemi et al., 2005). Chemical cues of perch (water from under adult predators, 15 cm length, fed on pike larvae until experiments) affect alone, but chemical and visual cues offered together are more effective.

Furthermore, it is shown that pike are attracted by alarm pheromone of fathead minnow, Pimephales promelas (Mathis et al., 1995; Chivers et al., 1996; indirect data by Wisenden & Thiel, 2001). In addition, pike demonstrate distinct foraging responses to artificial hypoxanthin-3(N)-oxide (Mathis et al., 1995) identified as an active component of ostariophysan fish alarm pheromones.

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Category: Olfaction & Gustation | Views: 2338 | Added by: nickyurchenko | Date: 2012-07-05

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