Biological adaptations of deep sea fishes Ashley Fooy, Rachel Krumbein, Gerald Marsh, Sandhya Rajagopal
Feb 25, 2016
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