Transcript Ichthyology Fall 2000 - University of North Dakota

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
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•
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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
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poster colors
queen angelfish
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poster colors
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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
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eye concealment
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eye concealment
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eye concealment
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eye enhancement
French angelfish
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eye enhancement
moray eel
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eyespots
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lateral stripes
common in schooling spp
For orientation &
pred. confusion
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lateral stripes
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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 cells
Most common in twilight-zone fishes 300-1000 m
Self-liminescence--liciferin/luciferace chem. react
Symbiotic luminescence--luminescent bacteria
in gland-like structures
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photophores
lanternfish
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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)
stridulation
Ariidae -- hardhead catfish
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 FW
Ex: 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 FW
2a. Freshwater Dispersants - SW is barrier
Ex: Ostariophysi; Esosidae; Percidae; Poeciliidae;
Lepisosteidae; Cichlidae
2b. Saltwater Dispersants - SW not barrier
Ex: 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
river
land barrier
erosion
limit
saltwater barrier
river
Ocean
Stream capture
river
capture
river
Ocean
Factors affecting distribution of fishes continued
• Dispersion Avenues/Barriers
– physical
• temperature; salinity
• divides; deserts
– biotic
• disease; competitors; predators
Fish Distribution
barrier
dispersal
A
mountains
time
center of origin
avenue
Tectonic plates & continental drift
Continental drift has changed barriers/avenues
barrier
center
avenue
center
Geologic Time
Scale
Teleostei
gars, bowfin
Acipenseriformes
Actinopterygii (Chondrostei)
Age of fishes
first fishes
Lungfishes present (Devonian); ancestors of sturgeons & paddlefish
Asia
Euramerica
SA
Africa
Ind.
Ant.
Permian 225 MYA
Aus.
Ancestors of gars and bowfin
Turgai Sea
Triassic--200 MYA
Origin of Teleostei
Euramerica
SA
Africa
Asia
Ind.
Aus.
Ant.
Jurassic -- 135 MYA
NA
Europe
Asia
Africa
Ind.
SA
Aus.
Ant.
Cretaceous -- 65 MYA
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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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