Reminder:

• Projects Due: 10 December

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Reading Assignment:Chapter 24: Flounders, Puffers, and Molas

ocean sunfish (Mola mola)

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Communication continued

1. Visual Signals continued• Thermoregulation• Intraspecific communication• Evasion of predators

2. Auditory Signals

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poster colors--complex color patterns

(common in reef fish)

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Function of Poster colors:• advertisement of territory ownership• contact between foragers• intraspecific communication of sex, status,

maturity (Labridae, Scaridae)• predator avoidance--cryptic on color

background• aposmatic coloration--advertisement of

danger (poison; spines)

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poster colors

butterfly fish

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poster colors

end

poster colors

queen angelfishend

poster colors

end

poster colors lionfish--aposmatic coloration

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disruptive coloration--patterns that disrupt outline

flicker fusion--patterned fish against patterned background

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disruptive coloration

camouflage

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disruptive coloration

camouflage

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disruptive coloration

camouflage

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disruptive coloration

camouflage

guitarfish

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disruptive coloration

camouflage

leafy seadragon end

eye concealment

end

eye concealment

end

eye concealment

end

eye enhancement

French angelfish

end

eye enhancement

moray eel

end

eyespots

end

lateral stripes

common in schooling spp

For orientation &

pred. confusion

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lateral stripes

end

polychromatism

• different colors in different individuals– ex: midas cichlid

• gold morphs win comp. for food

• rarely common in wild (prob. due to pred.)

– ex: annual killifish• brightly colored morphs dominant--greater

reproductive success early

• dull forms live longer--rep. success later in season

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Midas cichlid

annual killifish

special patterns

Ex: egg-shaped spots on male cichlids– mouth brooders– females take eggs into mouth after laying– attempts to pick up “dummy” eggs aids

fertilization

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egg spots

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photophores dragonfish

Light producing cellsMost common in twilight-zone fishes 300-1000 m

Self-liminescence--liciferin/luciferace chem. react

Symbiotic luminescence--luminescent bacteria

in gland-like structuresend

photophores

lanternfishend

Communication continued:

1. Visual Signals

2. Auditory Signals

Auditory Signals--for communication

• Stridulation -- produced by bone-to-bone contact– occurs in Catfishes (Ictaluridae, Ariidae)– pectoral spines rub against socket– amplified by swim bladder

• Vibrating muscles & swim bladder– Sciaenidae (drum family)

Ariidae -- hardhead catfish

stridulation

stridulation

Ictaluridae -- channel catfish

sound production through muscle vibration

Sciaenidae

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Zoogeography of Freshwater Fish• Defn: Study of geographic distribution of

animals

Zoogeographic Types of FW Fishes:

1. Euryhaline marine fishes - can enter FWEx: bull shark; saw fishes

common in areas where FW fish not well developed (e.g. Central America)

Zoogeographic Types of Fishes: continued

2. Obligatory Freshwater Fishes - must spend at least part of life cycle in FW2a. Freshwater Dispersants - SW is barrier

Ex: Ostariophysi; Esosidae; Percidae; Poeciliidae; Lepisosteidae; Cichlidae

2b. Saltwater Dispersants - SW not barrierEx: diadromous fishes; anguillids; gobies; salmon

Give rise to non-migratory forms (FW drum)

Factors affecting distribution of fishes

• Center of origin--distribution of ancestors– distribution of proto-species or higher taxon

Factors affecting distribution of fishes continued• Time of origin--first appearance of species

– geological changes• sea level

• mountain building/erosion

• stream capture

– continental drift - position of continents– change in physical variables (temp., salinity)– dispersal takes time

Stream capture

Ocean

river

river

erosion

saltwater barrier

land barrier

dispersi

on

limit

Stream capture

Ocean

river

river

capture

dispersal

Factors affecting distribution of fishes continued

• Dispersion Avenues/Barriers– physical

• temperature; salinity

• divides; deserts

– biotic• disease; competitors; predators

Adispersal

dispersal

dispersal

disp

ersa

ldi

sper

sal

center of origin

mountains

barrier

avenue

time

Fish Distribution

Tectonic plates & continental drift

avenue

center

center

barrier

Continental drift has changed barriers/avenues

first fishes

Age of fishes

Teleostei

Geologic Time

Scale

Actinopterygii (Chondrostei)

Acipenseriformesgars, bowfin

Permian 225 MYA

Euramerica

SA

Asia

Africa

Ant.

Aus.Ind.

Lungfishes present (Devonian); ancestors of sturgeons & paddlefish

Triassic--200 MYA

Turgai Sea

Ancestors of gars and bowfin

Jurassic -- 135 MYA

SA

Asia

Africa

Ant.

Aus.

Ind.

Origin of Teleostei

Euramerica

Cretaceous -- 65 MYA

NA

SA

Asia

Africa

Ant.

Aus.

Ind.

Europe

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Reminder: Lab Exam on Fishes next week:• 100 points (~50 questions)• Primarily identification (class, order, family, species, etc); Also

possibly questions from lab handouts and notes.– Ex: What is the lowest taxon that includes species on display?

• Only taxa on your lab handouts will be answers• Either standardized common or scientific names for species are

acceptable (Primary answer 2 pts/ Secondary answer ½ point extra credit)

• Tip: Step 1--learn to recognize fish; Step 2—learn species names and higher taxa

• Study by quizzing yourself (test your long-term memory)• Doors to lab open this week.• Lab will be closed Mon. for exam setup

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