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Respiration and Feeding

BIOL/FISH/OCEAN 250

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Respiration = the physical and chemical process of gas exchange

Ventilation = the mechanical process of putting gas exchange structures incontact with the exchange medium

► Pressure on Operculum—» Row of waterGUI FBcmenl

view of a ventilating fish generating a continuousrespiratory current

Buccol Cavtty

j

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Oesophagus-----------' I

- Pharynx http://images.tutorvista.com/content/respiration-animals/respiration-

mechanism-fish.jpeg

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water breathers air breathers

Megaptera novaeangliae

water breathers air breathersHumpback whale

Megaptera novaeangliae

^ , Humpback whaleCetoscarus bicolor *

Hard clams Mercenaria mercenaria

Wedell sealLeptonychotes wedelli 4

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Sunflower star Pycnopodia helianthoides

Marine mammal diving adaptations

Reduced heart rate (bradycardia)

Reduced blood supply to muscles &digestive system

More oxygen per kg

Most oxygen stored in blood

Myoglobin in muscles

Collapsible lungs and rib cage

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150

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'S im iOxygenated Deoxygenaied g j , W |

Water blood to body blood trom body a ' ,"] S f p| ,

mss' Diffusion > * • •

Flows out of Deoxygenatedoperculum blood from body

counter-current flow is key to oxygen extraction

Scherd and Piiper (1997) effkiency m aquatic respiration

Fish gills:

countercurrent

gas exchange

8Castro & Huber

Gill raker Lamellae

pp 80 torr("expired")

pp130 torr("inspired")

pp 80 torr("expired")

pp130 torr("inspired")

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because of the counter-current, there is a continuous diffusion gradient arterial pressuresexceed "expired" pressure

assuming expired air could reach pp 80torr...

If it were co-current, system comes to equilibrium.Rapid diffusion at the "inspired" end limits further diffusion

pp 50 torr(venous)

pp 100 torr(arterial)

pp 80 torr(arterial)

pp 50 torr(venous)

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Schmidt-Nielsen

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Fish Respiration

Cartilaginous fishSharks, skates, rays

Class Chondrichthyesspiracle

Ram ventilation*

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Spiracle

Pharynx

Enchangedlearning.com

Gill Surface AreaTop - Fast SwimmersBottom - Slow Swimmers

stop buccal pump,

start ram

ventilation

Summer flounder 268

Toidfith - 137

---- i/ ________

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0.4 0.6 0.8

Swimming speed (ms 1)> <

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Feeding• Filter feeding

• Herbivory- Microalgal scrapers

- Macroalgae

• Detritivore (Deposit Feeding)

• "Fishing"- Float/hide and wait

- Collection device-Pursuit

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Filter Feeding with mouth

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10

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Filter Feeding•with siphons

http://web.uconn.edu/ievanward/video/musselsum.MPG

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Stegastes variabilis Sea urchinsTop: Strongylocentrotus franciscanus

Bottom: Diadema antillarum 20

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Detritivores

# e

<4^4vr /. -fjr

Spaghetti wormPhylum: AnnelidaClass: PolychaetaLanice conchilega

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Semaphore crab

Heloecius cordiformis

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1 1 1 1 1 1 11

SI

Suction feeding

• nearly all fish use suction to some degree

• useful on a wide range of prey

• relatively cheap to produce

Has led to a remarkable

conservation of motor

pattern and kinematics;

these movements produce

a "wave of expansion"

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Jaw protrusion - usually refers to only the upper jaw or premaxilla

teleost with a non-protrusible upper jaw

teleost with a protrusible upper jawafter Schaeffer and Rosen, 1961

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time (s)

p rem^xi l la

maxi l la-

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Suction is effective only over a short distance• Have to get your face close enough to use suction

Extreme Jaw Protrusion

https://www.youtube.co Slingjaw wrasse Epibulus insidiatorm/watch?v=pDU4CQW

- This case is extreme, and includes lower jaw

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\\| ̂How do predators l-Bchoose their prey? JU ™

• readily availableJ Y. a ^ ,BJ 1 Br^

• easy to catch

• easy to eat (no spines)

• tastes good (no toxins; fatty)

• bigger before smaller

• easy to digest

EL ' ■'• ' " B_24_J

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Candlefish (smelt)

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If time, play octopus videoSometimes predation happens in ways otherthan we expect.

Change in smelt populations^Impacted stellar sea lions in Alaska

one smelt = 2.5 Pacific cod

Forage Fish Energy Content (kcal/g)