e.g.

Sea cucumbers - use their tubed feet to sift through sediments, extracting organic particles and detritus within

• Suspension feeding - Removal of suspended food particles from water column/

e.g.

Baleen whales - They have baleen plates hanging from their upper jaws which act like sieves to filter out krill and plankton from the water column

• Filter feeding - Feeding current is generated to remove food particles from water column, actively captures single food particles on cilia, hairs, mucus, sieve.

e.g.

Bivalve mollusks - have specialized gills equipped with cilia that create a current of water through their bodies. Small particles get trapped and transferred to their mouths for ingestion as water passes

• Ambush predation - Lying in wait and attacking prey suddenly.

• Capture predation - Actively searching for and pursuing prey.

• Scavenging - Feeding on dead organisms.

• Grazing - Consuming plant or algal matter.

e.g.

Sea lilies - use their branched arms to capture food particles from the water, attaching themselves to substrate and extend their arms into the water flow to capture plankton/ organic matter

• Active

  - aka active filter feeding

  -requires organism to actively create feeding currents, bringing water and organic matter into their filtering structures

  must supply its own energy to transport water over filtration surface

e.g.

Whales - actively feed by swimming through dense patches of prey like krill, opening their mouths wide and engulf large volumes of water containing prey

• Facultative

  - able to switch from passive to active feeding vice versa (according to ambient flow changes)

e.g.

Sea stars - they are able to extend their stomach into cervices in the sediment to digest organic material or they may use their tube feet to capture suspended particles from the water column

• Combined

  - continuously perform both passive and active feeding mechanisms simultaneously

  - found on organisms with collar sieving structure, where a beating flagellum creates a collar filter that passively capture food particles.

3 functional components

• Accelerating

  -rapid movements

  -maximized propulsions generated by strong caudal fin

• Cruising

  -undulation of body

  -lunate tail sheds water easily, minimize disruptive turbulence at posterior

• Maneuvering

  -accomplished by disc or diamond shaped body, permits body flexure and sudden change of movement

Rounded/ Torpedo shaped

Streamlined body (Ideal for acceleration, continual cruising)

Oval cross-section

Well adapted for open waters

e.g. Tuna, Mackerel, swordfish, sailfish

b) Compressiform

Compressed laterally from side to side

Can maneuver easily and accelerate in short burst

Well suited for schooling, maneuvering around coral reefs and living around wrecks or rocks

e.g. reel fish and moonfish

c) Depressiform

Flattened or flat shape

Live/rest on bottom of the sea floor

Flap fins up and down to swim through water

e.g. Flounders, Halibuts, Rays and Skates

d) Anguilliform

Eel-like

Elongated body

Round cross section

Blunt/ wedge shaped heads

Often have long dorsal and anal fins (sometimes lack paired fins)

tapering and rounded tails

Efficient swimming/maneuvering through narrow spaces

e.g. eels, hagfishes and lamprey

e) Filiform

Filament like (sometimes thread shaped)

Typically have narrow mouths and streamlined bodies (for swift movement through the water

e.g. pipe fish and trumpet fish

f) Taeniform

Ribbon shaped (for hiding in crevices)

Laterally compressed

Not fast but great in maneuvering

e.g. Oarfish, Ribbon, hairtail

g) Sagittiform

Arrow shaped

Ambush predators

Able to strike and accelerate in short bursts

e.g. Garfish, Pike, Needle fish and Barracuda

h) Globiform

Globe-like shapre

Slow swimmers

Modified fins for walking across sea bed

e.g. Frogfish, Lumpfish and Pufferfish

The position of a fish’s mouth can indicate whether a fish consumes prey from the

surface, in front of it, or on the sea floor.

Superior: positioned towards the surface and the fish feed on what is above them.

Terminal: positioned in the middle of the head and the fish either chases its prey or

feed what is ahead

Inferior: positioned toward the bottom usually prey upon or scavenge food on the

bottom.

1. Creates propulsive force to move through water:

- Most common way is undulatory mechanism

- Side-to-side motion created by alternate contractions of body musculature, first on one

side and then the other

2. To overcome water resistance and move efficiently in water, a fish has:

- Streamlined shape

- to reduce water resistance

- Scales on the body facing backwards (towards caudal fin) to reduce water resistance

- Its body surface covered in mucus (to reduce water resistance and friction)

3. Dimensions of movement

- The fins help maintain the stability of the fish.

- The dorsal and ventral fins reduce the tendency to roll and yaw.

- they also assist in turning movements.

- The pectoral and pelvic fins act as hydroplanes and control the pitch.

- The tail fin contributes to the forward thrust.

4. A fish must control its pitch, yaw and roll.

- Caudal fin provides thrust and control direction

- Pectoral fins acts as rudder, steer up or down, also helps in stop

- Pelvic fins mostly control pitch

- Dorsal fin controls roll

- Anal fin helps to stabilize a fish like the keel on the bottom of a boat

Most common form of swimming

Wave of contractions from head to tai

. Swings tail back and forth

. Strength and amplitude of contractions increase toward tail

2) MPF(Median and paired fin swimming)

Involve the use of Median and pectoral fin

Forward propulsion mainly by pectoral fin

Sea fans that grow in strong currents have flexible structures and point downstream of a current to prevent breakage and reduce drag forces in strong currents.

Coral polyps sting prey using nematocysts in their tentacles.

Crinoids use tube feet transport food between adjacent tube feet along the arm towards the mouth.

Active suspension feeding:

Barnacles use appendages like eulaterofrontal and prolaterofrontal cilia that create feeding currents, capture and transport particles into the mouth.

Bryozoans, phoronoids and polychaetes use ciliary sieving.

Salps filter feed by trapping particles mucus nets as they move through the water using front-rear jet propulsion.

Mussels use gills and labial palps to filter and select for food particles

Basking sharks, manta rays and whale sharks swim with their mouths open to create currents and collect water with suspended particles into their mouths. They use reticulated mesh of gill that retain food particles as water leaves the gills. This is known as ram filter feeding

Whale sharks suck water in a stationary position when food density is high. This is known as stationary suction feeding.

Facultative feeding:

Many intertidal barnacles use energy in areas with low flow velocity, while passively feed in higher flow velocities. This is known as facultative feeding. They use setals to capture particals.

Combined feeding:

Sponges use collar sieving, a choanocyte with a flagellum pumps water into a collar of microvilli that captures food.