Microsmatic
fish are represented by numerous freshwater and marine species in which the
well developed visual system provides most of the behavioural responses in
comparison with the less developed chemosensory system. Visually guided diurnal
or twilight predators as well as visually guided bentivorous and planktivorous
species form this group of fish. The chemosensory system of microsmatic fish is
active in providing their reproductive behaviour, social behaviour, spatial
migration, partially anti-predator behaviour and is weak or indifferent in
providing feeding responses.
Here, we
consider esociform fish.
Esocidae
5 species: Esox americanus, E. lucius, E. masquinongy, E. niger, E. reicherti
Fresh
waters of boreal Eurasia and Northern America
Northern
pike, E. lucius, and other
representatives of Esox genus,
including Amur pike, E. reicherti,
and some North American species, are apexpredators with the well developed
vision and lateral line system.
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
feeding behaviour, musky, E. masquinongy,
use vision and seismosensory system (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). It is also 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).
Dalliidae
3 species: Dallia admirabilis, D. delicatissima, D.
pectoralis
Fresh
waters of Bering Sea basin
Blackfish
primarily feed on crustacens (ostracods, cladocerans, copepods) and insect
larvae (ephemeropterans, hemipterans, dipterans, odonates), with the occasional
cannibalism and consumption of juvenile pike, E. lucius (Chlupach 1975).
However,
leading sensory systems in feeding and reproductive behaviours of blackfish are
unknown.
In winter
with the oxygen lack, blackfish concentrate in the vicinity of holes in the
ice, being easy to capture with the simple funnel-shaped traps made from strips
of tamarack or spruce (Andersen et al., 2004). In spring and fall, blackfish are also easily caught while
migrating to and from their summer habitats by placing the traps in narrow
channels, it is appear these traps are not baited.
Umbridae
4 species: Novumbra hubbsi and Umbra krameri, U. limi, U. pygmaea
Fresh waters
of Europe and Northern America
According
to rare observations, feeding behaviour of mudminnows is rather provided by
vision. For example, European mudminnow, U.
krameri, eat in an aquarium only living and moving invertebrates such as
cladocerans, copepods, Chaoborus
larvae, chironomid larvae, culicid larvae, mayflay larvae, Acellus aquaticus and tubificid worms (Kováč, 1997). Cannibalism
and hunting on juvenile fish in the nature are occasionally observed. However, Glasgow
& Hallock (2009) report that Olimpic mudminnows, Novumbra hubbsi, are caught by the minnow traps baited with the
chironomid larvae baits (15 g of chironomid larvae per one funnel-shaped trap).
So, the problem of sensory providing of feeding behaviour in mudminnows is
currently unclear.
On the
other hand, chemical cues may play an important role in social and
anti-predator behaviours of mudminnows. Indeed, central mudminnows, U. limi, demonstrate anti-predator
behaviour in response to conspecific chemical alarm cues (Wisenden et al.,
2007). Yet, mudminnows display comlex reproductive behaviour, from territory
guarding to parental care (Hagen et al., 1972; Bohlen, 1995; Kováč, 199
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