Ichthyology Final

Shoaling vs schooling

• shoaling

  • can be many species

  • individual activities

  • not organized

  • Can sometimes form a school if need be

• schooling

  • 1 species

  • synchronized swimming

  • Common goal

• Both

  • predator deterrent

Searching

• Active

  • Vision

  • Electroreception

  • smell

  • touch

  • hearing

• Passive

  • aggressive resemblance

  • ambush

• Cooperative hunting

Anti detection

• Protective resemblance

• Disruptive coloration

• Countershading

• mirror-sided

• Transparency

• Hiding

• Polarized schooling

Pursing predators

• cursorial

  • high speed sustained chases

  • Tuna, smallmouth

• Lurking

  • rapid acceleration

  • barracuda

• Luring

  • Uses a part of the body to attract prey within range

  • anglerfish

Deterring pursing

• Aposematic coloration

  • Warning colors

  • Surgeonfish, lion fish, fangblenny

Preventing attacks

• Shoaling reduces individual risk of attack

  • standing out in a shoal increases risk of attack

  • Dilution effect

  • Trafalgar effect - relay info to other members

  • Confusion effect

  • Fast start

Handling

• fish are eaten head first because they cant swim backwards

• rotational feeding - death roll, knotting

Preventing handling

• morphology that is difficult to swallow

  • hump

  • spines

  • inflation

• Toxins

• slime

• Schrekstoff - alarm substances

Herbivory

• only in teleosts

• pharyngeal mill and gizzard

• digestion more efficient at warmer temps

• strong preferences

Color production

• pigments are in chromatophores

• color is determined by genes and food

• Melanin - black, brown

• Guanine - white

• xantophyll - yellow

• carotenoids - orange, red, purple, blue

Static vs dynamic display

• static

  • longterm displays

• dynamic

  • color changing

  • bioluminescence

Acoustic communication

• startle/release

• courtship

• agonistic

• shoal formation (FRT)

• Methods

  • Farts (FRT)

  • Muscles w/ swim bladder

  • stridulations of bones

Chemical communication

• pheromones produced a behavioral or devo response in receiving individuals

Tactile communication

• uncommon

• fights, mating, parent-offspring interactions

Electrical communication

• Electric organ discharge is species and gender specific

• use different frequencies

Agonistic interactions

• Dominance hierarchies

  • linear - fish A is above fish B and fish B is above fish C

  • Despotic - Fish A is above fish B and C

• Territorially

• Home range

Symbiosis

• parasitism

  • + -

  • blood sucking, scale eating, burrowing, eat chunks

• mutualism

  • ++

    • cleaner fish

• Commensalism

  • +0

  • Remoras?

• w/ inverts

  • clownfish and anemones - mutualism

  • sea cucumber and pearlfish - commensalism sometimes parasitism

Diodontidae

• porcupine fish

• “two teeth”

• beaks

• durophagous

• inflation through buccal pumping

• broadcast spawn

Ceratioidei

• deep sea anglerfish

• sexual dimorphism

• facultative and obligate male parasitism

• Attracts prey with illicium, first dorsal fin ray that has bioluminescent bacteria

• defensive spines

• Sculling and quasi amiiform

Channidae

• snakehead

• Walking, facultative air breathers

  • suprabranchial organ

  • can survive out of water for several days

• live in shallow hypoxic waters

• aquariums

• native to Asia, Oceania, and Africa

• long dorsal fin, elongated body, truncate

• cycloid scales

• parental care, some mouth brood

• generalist predators - dangerous to humans

Micropterus

• black bass

• native to north america

• fusiform body, carangiform swimming

• pelagic generalist apex predators

• gonochoristic, polyandry, external fertilization

• males nest guard

• iteroparous

• some endangered, many invasive

Scorpaenidae

• scorpionfish

• venom

• camouflage

• produce sound

• zoophagous - durophagy and small fish

• nocturnal benthic ambush predators

• reefs, crevices, caves, seagrass

• native - pacific and indian ocean

• invasive - suez and Caribbean

• mostly oviparous, some ovoviviparous? a few viviparous

• some endangered

Hippocampus

• seahorses

• Camouflaged to shallow vegetation and reefs

• Tubular mouth, bony plates, dorsal propulsion, brood pouch

• flexible neck, fused jaw, prehensile tail

• circum-global

• planktivorous

• Monogamous, viviparous, iteroparous

• some endangered

Ophidiidae

• Cusk-eel

• modded pelvic fin - ventral fin

  • sensory organ

• no scales

• some deep sea

• wide range of maire habs

• gneralist pred and detritovore

• benthic, burrowing, solitary

• enhanced bone density

• translucent skin

• flexible diet

Cetomimoidea

• whalefish

• female, males, and larvae look very different

• bathypelagic

• anguilliform - subcarangiform

• Larvae

  • eat copepods

• males

  • enlarged liver, lost stomach and esophagus

  • they stop eating

  • smell out females

  • die after reproduction

• Females

  • gaping mouth

  • unique gill structure

• sensory pores, bad eyesight, scaleless

• data deficient

Regalecidae

• oarfish 3 species

• pelagic

• tropical to temperature worldwide

• amiiform

• batch spawn, no parental care

• hyperossified, no swim bladder

• long dorsal fin, no caudal or anal

• no scales

• epi-mesopelagic

• self amputation

• solitary

• filter feed

• oviparous

Nematogenyidae

• Mountain Catfish

• scaleless, elongated

• no adipose

• 3 pairs of barbell

• benthic durophagy

• external fert

• endangered

Bathysauridae

• deep-sea lizardfish

• sagittiform

• large liver, flat head, large tough scales

• needle like teeth that collapse inwards

• apex pred

• data deficient

• hermaphrodites

Stomiidae

• barbeled dragonfish

• barbeled chin, long gaping laws

• photophore

• some loosejaw

• apex predator

• asynch diel vertical migration

• iteroparous, batch

• data deficient

Coregoninae

• whitefish

• northern hemisphere

• cold-water, thermal migration

• diel vert mig

• benthic molluscivore

• low parental investment

• ecotypes in same lakes - plasticity

• declining pop

Apteronotidae

• ghost knifefish

• long anal fish

• EOD

  • courtship, aggression, communication

• small/reduced eyes

• south america, deep fast water

• eats fish, plankton, benthic foraging, scales

• gymnotiformes

• dorsal filament

• data deficient

Mormyridae

• African elephant fish

• west and central africa in river basins

• scavenge and eat inverts

• lat compressed

• elongated chin appendage - schnauzenorgan

  • Used for electroreception

• nocturnal, males are territorial, school

• external fert

• nest building and guarding

• EOD

• large brain to body ratio

Megalops

• Tarpon 2 species

• 4-8 ft long

• large flat silvery scales

• facultative air breathing - modded swim bladder

  • obligate as larvae

• unique larval stage

• countershading

• 5 types of cone cells

• rolling

• vulnerable

Amiidae

• bowfin

• cycloid scales, heterocercal, long dorsal

• eyespot on tail

• facultative air breathers - modded swim bladder

• buccal pumping

• wide range of environs

• amiiform

• North america wetlands, rivers, swamps, lakes

• live deep

• nest building, paternal care, and courtship

• survive out of water for upto 5 days

• least concern

Etmopteridae

• Lantern Shark

• deep water

• most are relatively small

• photophores on underside

• subcarangiform

• spines behind fin

• bioluminescent fins

• middle trophic carnivore

• ovoviviparous

Why the fish distribution of today?

• global

  • continental drift

• Regional

  • river and mountain formation

• Local

  • Chemistry

  • temp

  • water flow

  • productivity

  • gradients

  • hab size

Types of processes that influence distribution

• Vicariance

  • species are shaped by passive isolation

• dispersal

  • subpop of an ancestral species migrates across a geographic barrier

barriers to dispersal for marine fish

• continents

• depth

• salinity

• temp

Realms

• eastern pacific

• Western atlantic

  • hotspot: Caribbean

• Eastern atlantic

• Indo-west pacific

  • hotspot: Indo-Australian Archipelago

Freshwater fish types

• primary - only fresh

• secondary - tolerant

• peripheral - complete part of their life at sea

Freshwater realm

• Neartic - North american

• Palaeartic - North eurasia

• Neotropical - SA

• Sino-oriental

• African

• Australian

Freshwater diversity trends

• High in tropical lakes and rives

• low on island

• volume, diversity, and stability

Species flock

taxon that dominates a habitat

Competition

• resources not abundant enough

• resource partitioning - spatiotemporal specialization

• competitive displacement

  • usually caused by invasive species

  • hab displacement, pop decline, local extinction

Predation

• density dependent changes - prey pop size determines impact of predation

• depensatory - opposite ex. schooling

impacts of parasitism

• predator-prey interactions

• behavior

• social interactions

Herbivory

• 25-50% of diet is vegetation

• correlated w/ latitude

• impacts

  • fewer aquatic insects

  • seed dispersal

  • coral health

  • anti-pred adaptations

  • algal biomass

trophic levels

• 10% energy loss

• eating low trophic level food is better for environ

Torpedinidae

• electric ray

• round shape

• EOD

• pred with electricity

• viviparous

Polypteridae

• bichir 12 species

• facultative air breathers

• lungs

• poor eyesight, good sense of smell

• modded dorsal

• external larvae gills

• african

• hears good

• noctural predator

• suction feed

• courthship

• anguilliform

• LC

Acipenseridae

• sturgeon

• cartilage skeleton

• dorsal fin is back

• barbels

• toothless

• bony scutes

• heterocercal

• physostomus

• anadromy

• benthic crusiers

• endangered

Lamniformes

• Mackerel sharks 15 species

  • basking shark, great white, mako, porbeagle, megamouth, thresher, croc, sand tiger, goblin

• fusiform, large mouth, 5 gill slits, countershade, 2 dorsal

• some endothermy

• ovovivipary

• good sight

• global, pelagic

• opportunistic predat expect for filter feeder

Hexanchidae

• cow shark 5 species

• 6-7 gill slits

• cylindrical

• short dorsal

• notch in caudal

• ovovivipary

• mesopredators

Myliobatidae

• eagle ray

• pelagic

• diamond shape

• sometimes serated stinging barbs

• lobe under snout for digging

• viviparous w/ diapause

• electroreception

• durophagy

• benthic feeding

• jumps