biological adaptations of deep sea fishes
DESCRIPTION
Biological adaptations of deep sea fishes. Ashley Fooy, Rachel Krumbein, Gerald Marsh, Sandhya Rajagopal. Introduction. 60% of the Earth's surface Boundaries; part of the ocean that spans beyond the continental shelf Upper bound of 200m lower 11,000m Pressure; 1000x the atmospheric pressure - PowerPoint PPT PresentationTRANSCRIPT
Biological adaptations of deep sea fishesAshley Fooy, Rachel Krumbein, Gerald
Marsh, Sandhya Rajagopal
Introduction• 60% of the Earth's surface
• Boundaries; part of the ocean that spans beyond the continental shelf o Upper bound of 200m
lower 11,000m
• Pressure; 1000x the atmospheric pressure
• Temperatures; -1C to 4C
Adaptations • High Pressures
o Reduced skeleton and muscle mass
o Piezolytes; prevent distortion of molecules
• Colder temperatures o Flexible proteins and
unsaturated membranes
Adaptations (con't)• Food availability - limited
o Large mouth/jaw hinges, teeth that hook inward, and expandable stomachs
• Reproduction o Sexual parasitism
Bioluminescence • 80% of deep sea
fishes
• Photophores; light emitting organso Intrinsic; chemical
reactions under neural/hormonal control
o Extrinsic; symbiotic relationship with bioluminescent bacteria under mechanical control
Bioluminescence (Con't)• Usage
o Attract/ startle preyo Confuse predators
Mimic light traveling in a different direction
o Attracting a mateo Counterillumination
Use photophores to match the light radiating from the environment
Velvet Belly Lantern Shark• Important ecological
role; one of the most abundant predators
• Captured/discarded by several off-shore fisheries
• Nine luminous zones (hormonal control)o Counterillumination (produce
light to match an illuminated background)
o Cooperative swimming/hunting and sex signaling
Anglerfishes
• Order - Lophiiformes, Suborder - Ceratioidae
• Structure of escal photophoreo fluorescent bacteria
• Purpose of escal photophore
Anglerfishes-bioluminescence
Anglerfishes - feeding and locomotion
• lie-in-wait predatoro interesting adaptation
when feeding on the bottom
o diet
• common locomotive patternso passive driftingo movement when
threatened
Anglerfishes - reproduction
• two reproductive strategieso fusiono temporary
attachment
• sexual dimorphism
Male anglerfish larva
Deep-sea hatchetfish• Argyropelecus affinis or
Argyropelecus hemigymnus
• Adaptationso Upward facing snout,
moutho Upward facing, large,
tubular eyeso Narrow silhouettes,
silver sides
Deep-sea hatchetfish• Bioluminescence
o Camouflage, counterillumination
o Can rapidly alter luminescence according to background
o Possible nitric oxide modulation of luminescence
• Zooplanktivorous
• Lens pigmentationo Increased acuityo Detect own groupo Avoid enemieso Chemical properties
differ from other species with coloration
• Sexual dimorphism in olfactory organso Males larger than
femaleso Pheromone responses
Umbrella Mouth Gulper eel
SaccopharyngiformesEurypharynx pelecanoides
Adaptations: Pelican eel
• Enlarged mouth & heado "Largest gape size of any
vertebrate in relation to body size" (Nielsen, 1989 p.194).
• Extended lateral line
• Luminous filaments on caudal fin used for hunting
• Leptocephalic Larveo Similar to relatives they
breed once and die (semelparity)
Umbrella mouth Gulper eelAmbush hunting• Uses lateral line to detect prey
• Lunges at prey using water to open mouth similar to a parachuteo Only has to expend energy
closing jaw
• Typically used when hunting small prey
Lure hunting
• Ambush hunting of larger prey items
• Bioluminescent filaments on caudal fin are used to lure prey closer
• Before they swallow prey they digest it in its gape with an acidic substrate.
Conservation• Largest ecosystem with
least know about ito Millions of square miles of
unexplored ocean floor
• Possibly the largest reservoir of biomass on the planeto Number of species living
there may outnumber terrestrial animals
• Millions of years of evolution in a harsh environment requires very specialized adaptations
• Practical uses of fish adaptations for developing medicine
ConservationEnvironmental changes• "Undetected mass extinctions"
• So few interactions with them we have no idea if populations are declining
Human impacts • Deep ocean oil spills
o Event horizon spill
• Overfishing of top predators & fishing down the food web
Conservation is important because the benefits these fish can provide is highly unknown
Conclusion and future directions• more research is
needed for all species
• new technology• biological
adaptations are key to success in the deep sea