DeepSea Fish Adaptations

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Deep-Sea Fish Adaptations

• KERSTIN EDBERG
• VERTEBRATE NATURAL HISTORY
• BIO 475

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The Zones

• Mesopelagic
• Bathypelagic
• Contains 75 of Ocean
• Deepwater Benthic
• Constant contact

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Environmental Conditions

• Light
• 1,000 m darkness
• Temperature
• 20o C to 5 or 6o C in a few hundred meters
• Changes slowly
• Pressure
• Inc. 1 atm each 10 m
• Range of 20-1000 atm
• Fish live in range of 200-600 atm
• Cannot survive outside these limits

• Salinity
• Constant below a few hundred meters
• Food
• No Primary Production
• Fall from above
• Bacteria
• Sludge

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The Fish

• 90 of all fish belong to 2 Families
• Gonostomatidae and Myctophidae
• Most diverse near continents
• Arctic
• Antarctic
• Actinopterygian species are rare
• Lampridiformes and Bercyiformes (ancient)
• Evolutionary Origins Different

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Adult Morphology

• Bathypelagic
• Larval traits
• Flabby Bodies
• Weak Skeletons
• No scales
• Poor CNS
• Lateral line
• Olfactory
• Small eyes, kindeys, hearts
• Reduced or abscent swimbladders

• Mesopelagic
• Muscular bodies
• Well developed skeleton
• Scales
• W.D. Nervous system
• Large Heart and Kidneys
• Large Eyes
• Photopigment concentration
• Lack Spines
• Some swimbladders

• Deep Water Benthic
• Muscular Bodies
• Elongate Bodies
• W.D organ systems
• All other characteristics variable

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Bioluminescence

• Symbiotic bacteria
• Blood flow
• Blue Green
• Red and Yellow
• 90 of Mesopelagic fish
• Camouflage/Predator Avoidance
• Defense
• Feeding

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Eyes

• 2,000 m depth
• Tubular
• Retinas
• 2 parts / 2 functions

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Finding Food

• Vertical Migrations
• Stomiatoids
• Barbels
• Bioluminescence
• Saber-toothed Viper fish
• Anglerfishes
• Modified dorsal spine (illicium)
• Esca
• Coelom lining

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Feeding

• Hinged Heads and Distensible Stomach
• Both allow for eating prey items much larger than
  themselves
• Teeth
• Shape and Placement
• Filter Feeding

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Reproduction

• Parasitic Males
• Anglerfish
• Hermaphroditic species
• Self fertilization?
• Sounds Production
• Swimbladder
• Bioluminescence

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Larvae

• Epipelagic Larvae
• Large numbers
• Large Benthic Eggs
• Larval Development

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Cool Fish!!

• Anglerfish
• Black Dragonfish
• Cusk eel