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Zoogeography and Habitat Adaptations

Fish Distribution Patterns

  • Divison of Regions: FW and Marine

    • 58% MARINE

    • 41% Fw

  • MARINE:

    • Epiplegaic: surface-200m

      • 1.3% of total species

    • Deep pelgaic fishes: 1400 species

      • Mesoplegaic: 200-1000m

      • Bathypelagic: deeper than 1000m

    • Deep Benthic:

      • 6.4% of species

    • Littoral.contential shelf fishes:

      • Inhabit the shore and shelf above 200m

      • 45%

  • Freshwater:

    • Higher diversity: 1 species by 15km3 of water

    • Higher likelihood of genetic isolation

    • More energy available to support food webs

    • DIVISION:

      • FW Primary: strictly confined to FW

        • Disbtution not through dispersal

      • Secondary FW: may occasionally enter salt

      • Peripheral FW: spend part of their lifecycle in fresh and salt water

    • Islands with FW species have secondary and peripheral species; primary species could not have bene disbtuuited through dispersal because they are intolerant to salt water

Marine Zoogeographic Regions:

  • Indo-West Pacific: most diverse

    • ⅓ of species of shallow marine fishes

  • Western Atlantic

  • Eastern PAcific

  • Eastern Atlantic

  • Regions separated by Continents

  • Species richness in tropic areas

  • Dispersal: Typical pattern of fishes traveling and speciation occurring

    • occurs Across preexisting barriers that are not easily re-crossed

      • Ex: Sheepshead minnow (Cyprinodon vareigatus)

      • Ability to colonize many habitats by dispersing many miles across ocean waters

      • Ability to tolerate wide ranges of salinity

Freshwater Zoogeographic Regions:

  • Neartic

  • Neotropical

  • Afrotropical

  • Indo-Malay

  • Australian

  • Paleartic

Non-Dispersal Distributon

  • Present distribution= influenced by past arraignments of continents

  • Pangea: 430 mya

    • Movement between regions was easier due to the connection

    • Began to break apart 130 mya

  • Vicariant Events: tectonic, climatic, or oceanographic occurrences that isolate previously connected populations

    • Ex: continental drift and species of lungfishes

    • Dominant mod, esp in fw fishes

    • S. tritor(spnasih mackerels): sister species to the rest of the mackerel group

      • Located in africa

      • Other makreles are spread globally

      • NA Mackerel: Scomberomorus maculatus

Special Habitats

  • Fishes have colonized any ecosystem with some permanence or predictability

  • Principle of Convergence: the stronger the selection pressure, the more similar unrelated species will be

  • Extreme habitats are colonized to gain comptieitve advantage

  • THE DEEP SEA:

    • Occurs in a vertical basis

    • Characteristics:

      • Photophores: light emitting organs

      • Large mouth w/dagger like teeth

      • Enlarged tubular eyes/ or reduced eyes

      • Chin barbels

      • Dorsal fin rays modified as lures

    • Convergent evolution among species

    • Ecological Pressures:

      • Pressure:

        • Fishes made up of incompresible structures = water with dissolved compounds

        • Insensitive to pressure proteins

        • No gas bladder/ adjusted lipid filled gas bladder

          • Rete mirabile: Capillary network involved in gas secretion into the bladder

          • Or Physoclistous

      • Temperature

        • Strong predictor of vertical distribution due to perm. thermocline

        • Only a stressor to fish that move vertically

      • Space: large volume makes it difficult to find food, conspecifics, and mates

        • Sexual dimorphism

        • Ex: Male Anglerfish: dwarfed, sensitive olfactory organs and extensive red muscle, enlarged eyes, high lipid reservers

        • Ex: bristlemouths; smaller males, but are protandrous hermaphrodites

      • Light:

        • Modified eyes that are sensitive to light

        • Biolumnescence: evolved independently in 5 superorders

      • Food: food is scarce-> all marine food chains originate in the euphotic zone

        • Deep sea fishes carnivorous

        • Large mouths to make sure they can take advantage of any feeding opportunity

        • Food attraction by lures and energy conserved as much as possible

        • Mesopelagic fishes: vertical migration to feed at night

  • POLAR REGIONS

    • Anatartic Water Temperatures: -2, 2C)

      • Antarctic notothernoids: antifreeze compounds in blood; will not freeze down to -6C

        • Cannot tolerate high temps-> means they are endemic

      • Artici Fishes: fewer endemic species

        • Most are cold tolerant atlantic or pacific species

        • Antifreeze compounds and production

          • Production adjusted by tempes

        • Toleration of temps -2 to 20 C

  • ARID

    • Desert fishes

    • Must be tolerant to extreme salinity, alkalinity, temp and depltted OD

    • Withstand flashfloods and droughts

    • Adaptions:

      • Life history with diapause(hiberation) during dry period

        • Diapause is integrated into the lifecycle

        • EX: Cyprinodontiforms, Austrofunduls myseri

          • Eggs are stored for a year in the soil

      • Accessory respiratory structures for using atm O2

      • Estivation: where adults pass the dry season

    • Ex: Clarias catfish

  • HIGH ENERGY ZONES

    • Wavy shoes, rapids in rivers, streams, waterfalls

    • Adaptions:

      • Depressed small body; flattened ventral surface

      • Suction device

      • Subterminal or inferior mouth

      • Missing swim bladder

      • Modofiications to respiratory behavior

      • Large, horizontally oriented pectoral fins

      • Ex: Waterfall climbing Sirajo goby

  • CAVES:

    • Advantages: little to no compeptiors, predators, and constant moderate climate

    • Disadvanges: no light, infreqnet food

    • Adaptations:

      • Lack of Pigmentation

      • Reduced squamation

      • Loss of light receptors (blind)

      • Expanded lateral line and chemoreceptors

      • Will consume more and build large fat supply when given unlimited food; adaptions to irregular food supply

      • Producer fewer, larger eggs, long parental care, low reproductive rates

      • EX: CRYPTOROA THAMICOLA

        • Waterfall climbing fish

        • Has the adaptions for cave fishes and fishes living in high-energy enviroments

Zoogeography and Habitat Adaptations

Fish Distribution Patterns

  • Divison of Regions: FW and Marine

    • 58% MARINE

    • 41% Fw

  • MARINE:

    • Epiplegaic: surface-200m

      • 1.3% of total species

    • Deep pelgaic fishes: 1400 species

      • Mesoplegaic: 200-1000m

      • Bathypelagic: deeper than 1000m

    • Deep Benthic:

      • 6.4% of species

    • Littoral.contential shelf fishes:

      • Inhabit the shore and shelf above 200m

      • 45%

  • Freshwater:

    • Higher diversity: 1 species by 15km3 of water

    • Higher likelihood of genetic isolation

    • More energy available to support food webs

    • DIVISION:

      • FW Primary: strictly confined to FW

        • Disbtution not through dispersal

      • Secondary FW: may occasionally enter salt

      • Peripheral FW: spend part of their lifecycle in fresh and salt water

    • Islands with FW species have secondary and peripheral species; primary species could not have bene disbtuuited through dispersal because they are intolerant to salt water

Marine Zoogeographic Regions:

  • Indo-West Pacific: most diverse

    • ⅓ of species of shallow marine fishes

  • Western Atlantic

  • Eastern PAcific

  • Eastern Atlantic

  • Regions separated by Continents

  • Species richness in tropic areas

  • Dispersal: Typical pattern of fishes traveling and speciation occurring

    • occurs Across preexisting barriers that are not easily re-crossed

      • Ex: Sheepshead minnow (Cyprinodon vareigatus)

      • Ability to colonize many habitats by dispersing many miles across ocean waters

      • Ability to tolerate wide ranges of salinity

Freshwater Zoogeographic Regions:

  • Neartic

  • Neotropical

  • Afrotropical

  • Indo-Malay

  • Australian

  • Paleartic

Non-Dispersal Distributon

  • Present distribution= influenced by past arraignments of continents

  • Pangea: 430 mya

    • Movement between regions was easier due to the connection

    • Began to break apart 130 mya

  • Vicariant Events: tectonic, climatic, or oceanographic occurrences that isolate previously connected populations

    • Ex: continental drift and species of lungfishes

    • Dominant mod, esp in fw fishes

    • S. tritor(spnasih mackerels): sister species to the rest of the mackerel group

      • Located in africa

      • Other makreles are spread globally

      • NA Mackerel: Scomberomorus maculatus

Special Habitats

  • Fishes have colonized any ecosystem with some permanence or predictability

  • Principle of Convergence: the stronger the selection pressure, the more similar unrelated species will be

  • Extreme habitats are colonized to gain comptieitve advantage

  • THE DEEP SEA:

    • Occurs in a vertical basis

    • Characteristics:

      • Photophores: light emitting organs

      • Large mouth w/dagger like teeth

      • Enlarged tubular eyes/ or reduced eyes

      • Chin barbels

      • Dorsal fin rays modified as lures

    • Convergent evolution among species

    • Ecological Pressures:

      • Pressure:

        • Fishes made up of incompresible structures = water with dissolved compounds

        • Insensitive to pressure proteins

        • No gas bladder/ adjusted lipid filled gas bladder

          • Rete mirabile: Capillary network involved in gas secretion into the bladder

          • Or Physoclistous

      • Temperature

        • Strong predictor of vertical distribution due to perm. thermocline

        • Only a stressor to fish that move vertically

      • Space: large volume makes it difficult to find food, conspecifics, and mates

        • Sexual dimorphism

        • Ex: Male Anglerfish: dwarfed, sensitive olfactory organs and extensive red muscle, enlarged eyes, high lipid reservers

        • Ex: bristlemouths; smaller males, but are protandrous hermaphrodites

      • Light:

        • Modified eyes that are sensitive to light

        • Biolumnescence: evolved independently in 5 superorders

      • Food: food is scarce-> all marine food chains originate in the euphotic zone

        • Deep sea fishes carnivorous

        • Large mouths to make sure they can take advantage of any feeding opportunity

        • Food attraction by lures and energy conserved as much as possible

        • Mesopelagic fishes: vertical migration to feed at night

  • POLAR REGIONS

    • Anatartic Water Temperatures: -2, 2C)

      • Antarctic notothernoids: antifreeze compounds in blood; will not freeze down to -6C

        • Cannot tolerate high temps-> means they are endemic

      • Artici Fishes: fewer endemic species

        • Most are cold tolerant atlantic or pacific species

        • Antifreeze compounds and production

          • Production adjusted by tempes

        • Toleration of temps -2 to 20 C

  • ARID

    • Desert fishes

    • Must be tolerant to extreme salinity, alkalinity, temp and depltted OD

    • Withstand flashfloods and droughts

    • Adaptions:

      • Life history with diapause(hiberation) during dry period

        • Diapause is integrated into the lifecycle

        • EX: Cyprinodontiforms, Austrofunduls myseri

          • Eggs are stored for a year in the soil

      • Accessory respiratory structures for using atm O2

      • Estivation: where adults pass the dry season

    • Ex: Clarias catfish

  • HIGH ENERGY ZONES

    • Wavy shoes, rapids in rivers, streams, waterfalls

    • Adaptions:

      • Depressed small body; flattened ventral surface

      • Suction device

      • Subterminal or inferior mouth

      • Missing swim bladder

      • Modofiications to respiratory behavior

      • Large, horizontally oriented pectoral fins

      • Ex: Waterfall climbing Sirajo goby

  • CAVES:

    • Advantages: little to no compeptiors, predators, and constant moderate climate

    • Disadvanges: no light, infreqnet food

    • Adaptations:

      • Lack of Pigmentation

      • Reduced squamation

      • Loss of light receptors (blind)

      • Expanded lateral line and chemoreceptors

      • Will consume more and build large fat supply when given unlimited food; adaptions to irregular food supply

      • Producer fewer, larger eggs, long parental care, low reproductive rates

      • EX: CRYPTOROA THAMICOLA

        • Waterfall climbing fish

        • Has the adaptions for cave fishes and fishes living in high-energy enviroments

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