Lab 6:Senses,

Suckers, and Catfish

channel catfish (Ictalurus punctatus)

golden redhorse (Moxostoma erythrurum)

Four main sensory systems in fish

• Chemoreception – olfaction and taste

• Acoustico-lateralis – hearing and lat. line

• Electroreception

• Photoreception/vision

Chemoreception -- olfaction• Olfaction “smell”

– Nares– Used for food detection,

orientation, predator avoidance

Nare function of american eel (Anguilla anguilla)

Nares of different fishes

• The # of lamellae (folds) usually correlate with the ability to smell

• Range from 0 (seahorses) to 230 (porgy).

Chemoreception Examples

• Salmonid homing – adults use nares to detect chemical signature of native stream

• Cyprinids, Catostomids use papillae on their lips• Ictalurids use barbels, note the orientation of the barbels• How do you test these senses….plug or block them!

Auditory Systems-- Acoustico-lateralis

• Inner ear and otoliths

• Swim bladder and Weberian apparatus

• Lateral Line

Inner Ear -- Otolith• Otolith (hard earstone) – held in a fluid sac, saculus, 3x

density• Hairs inside the sac detect otoliths movement, fish

moves otolith stays in place cause it is more dense• Also balances the fish in three planes

Swimbladder and Weberian Apparatus• Bony connection between swimbladder and

inner ear,• Dense waterless dense air causes swim

bladder to vibrate, the Weberian apparatus transmit vibrations to the inner ear.

Lateral line – “distant touch”

Neuromast

Hair cells

Electroreception• Widespread among fishes….except teleosts

– Freshwater examples: gymnotid, electric catfishes, African electricfishes…the mormyridae, really cool!

– Useful in finding food, especially in turbid environments

Vision

• Most can see color, but more rods then cones• Rods are much more precise, therefore used

to detect movement• Tapetum lucidum, which amplifies the incoming light,

layer of guanine crystals which glow at night.

Eye orientation determines what a fish can see….evolutionary consequences

Eyes of Wisconsin fishes

Fish Identification Catostomidae and Ictaluridae

Family Catostomidae -- suckers

• Small family only 68 species but successful• In North America often most abundant• Primarily bottom dwellars• Subterminal mouths, fleshy• Fins in primitive position• Two main forms Lotic and lentic….?

White sucker (Catastomus commersoni)

First, what does lotic or lentic mean…?

Lotic – running water streams, rivers

Lentic – standing water lakes, ponds

How do you remember the difference….?

Lotic = Flowing

Lotic and lentic catostomids

LOTIC

Lotic and lentic catostomids

LENTIC

smallmouth buffalo (Ictiobus bubalus)

carpsucker

carpsucker

Lotic and lentic catostomids

In Betweens

White suckerCatostomuscommersoni

Quillback Carpiodes cyprinus

Genus Catostomus

White sucker (Catostomus commersoni)• Lips are very papillose (bumpy)

Shorthead redhorse (Moxostoma macrolepidotum)

Golden redhorse (Moxostoma erythrurum )• Large scales, larger then Catostomus• Lower lip formed differently between two species

Shorthead redhorse (Moxostoma macrolepidotum)

Genus Moxostoma

Golden redhorse(Moxostomaerythrurum)

Genus Hypentelium

Northern hog sucker (Hypentelium nigricans) • Have indented head• 3 saddle patches on back

Quillback (Carpiodes cyprinus)– Have extended ray on dorsal fin– Subtriangular subopercle

Genus Carpiodes

Genus Ictiobus nevermind

Smallmouth buffalo (Ictiobus bubalus)• Looks like a carp with no barbels or spines• Semicircular Subopercle

Family Ictaluridae -- CatfishesWhiskery snout, 1-4 pair of barbels, 1 from maxillae

Small eyes

Flattened head

Adipose fin

With or without sclaes, some with bony plates

Stout spine from pectoral and dorsal fins

Catfishes - Armour

Genus Ameiurus -- bullheads

black bullhead (Ameiurus melas)

brown bullhead (Ameiurus nebulosus) yellow bullhead (Ameiurus natalis)

Black, yellow, and brown bullheads • Look at CHIN barbels first, yellow bullhead are

lighter then black or brown• Black bullhead all one color, brown are mottled

Genus Noturus -- madtoms

Stonecat Noturus flavus

Tadpole madtom Noturus gyrinus• Look at adipose fin and caudal fin, distinct adipose

are bullheads, connected or almost connected are madtoms

Tadpole madtom (Noturus gyrinus) Stonecat (Noturus flavus)

Connected – no notch

Genus Ictalurus

Channel catfish Ictalurus punctatus• Deeply forked tail

Channel catfish

Bullhead