Lecture 17 - Behavioural Ecology of Fish

Question 1

What percentage of reef fish are herbivores?

Answer 1

25%

Question 2

What percentage of primary production of algae on the reef is removed by herbivores?

Answer 2

50%

Question 3

Why are parrotfish important species in coral reef communities?

Answer 3

Partake in the bioerosion process.

Grind down calcium carbonate skeleton, which falls among the reef and fuses together, leading to reef growth.

Question 4

Give a territorial herbivore.

Answer 4

Farming damselfish.
Selectively weed out unpalatable algae and maintain a highly productive farm within their hiding hole which they feed on.

Question 5

What is the role of planktivores in coral reefs?

Answer 5

Form coupling of offshore plankton communities and coral reef communities, bringing nutrients onto the reef.

Question 6

Give an example of a nocturnal planktivore.

Answer 6

Squirrelfish.
Take advantage of the diurnal-migrating plankton.
Spread out as a group for hunting, and vocalise as they find a plankton school.

Question 7

Are the majority of fish on reefs predators or prey?

Answer 7

Predators.

Question 8

Give two examples of predators on coral reefs.

Answer 8

• Great barracuda; has big teeth.

- Red hind; has large extendable mouth that creates a vacuum and sucks prey in.

Question 9

When do prey have a competitive advantage?

Answer 9

When light levels are high.

Question 10

Give an example of a species with a sit-and-wait strategy.

Answer 10

Spoon-nosed eel.

Highly camouflaged against its surroundings, lives in burrow, and emerges rapidly and grabs prey species.

Question 11

Give an example of a species that hunts through pack hunting.

Answer 11

Comb grouper.

Question 12

What is the benefit of shadow feeding?

Answer 12

By hunting together, provide competitive advantage over prey from a confusion effect.

Question 13

Give an example of two species that hunt through shadow feeding.

Answer 13

Bar jack and southern stingray.

Have different feeding strategies, but prey makes more mistakes than if only faced by one of them.

Question 14

What is nuclear hunting?

Answer 14

Two or more species hunting together.

Question 15

Give an example of nuclear hunting.

Answer 15

Moray eels and Coney.

Question 16

Describe the work of Alex Veil.

Answer 16

Described complex behaviour interaction between Coney and moray eel.
Coney vocalises to moray, inviting to hunt.
Coney chases fish towards hole, performs a dance to indicate location of prey.

Question 17

Give a defence mechanism of angelfish.

Answer 17

Have high bodies, as most predators are gape-limited.

Question 18

Give a defence mechanism of triggerfish.

Answer 18

Can make their bodies temporarily taller using spines, increasing body height, preventing being eaten by gape-limited predators.

Question 19

What are chromatophores?

Answer 19

Temporarily ink-filled cells, through hormones flood ink to the surface of the cell, allowing fish to change colour quickly.

Question 20

Give an adaptation of parrotfish.

Answer 20

Has ‘sleeping colours’, uses chromatophores for hiding in low light levels.
Secretes a bubble of mucus that encases the whole fish, preventing it from releasing olfactory cues about its location for predators.

Question 21

Give an example of permanent advertising on the reef.

Answer 21

Queen angelfish, swim high above the reef using bright colours to signal to one another the edges of their territory.

Question 22

Give an example of temporary advertising on the reef.

Answer 22

Bluelip parrotfish.
Males change colour, demonstrating their health.
A measure of quality, attracting females.

Question 23

Give an example of a symbiotic relationship,

Answer 23

Orange spotted goby and snapping shrimp.
Shrimp has poor eyesight, good at digging burrows.
Goby good eyesight, nowhere to live.

Question 24

Give an example of commensalism.

Answer 24

Juvenile bar jacks developed tolerance to the stinging cells of jellyfish, live in their tentacles.

Pearlfish vocalises, convincing sea cucumber to open its anus. Lives within the anus of the sea cucumber.

Question 25

What is commensalism?

Answer 25

Where one species gains an advantage from a mutualistic relationship, but the other species does not gain an advantage or a disadvantage.

Question 26

Give an example of mimicry.

Answer 26

Wrasse blenny imitates initial phase of blue-headed wrasse, gaining protection from predators by imitating a non-preferred prey species.

Question 27

Give an example of aggressive mimicry.

Answer 27

Juvenile tiger grouper has colouration of initial phase blue-headed wrasse, uses this to get near prey.

Question 28

What is reciprocal mimicry?

Answer 28

Both species benefit from looking like the other.

Question 29

Give an example of reciprocal mimicry.

Answer 29

Goatfish and yellowtail snapper swim in two-species schools; goatfish have barbels that allow them to smell hidden prey, yellowtail snappers faster at catching prey.

Question 30

Give an example of cleaning symbiosis.

Answer 30

• Gobies swim into the mouth of Nassau groupers and clean parasites off the gills.
• Shrimp pick off scales and decaying skin.

Question 31

Describe the intelligence of a cleaning organism, a ‘cleaner’.

Answer 31

• Can recognise 1000 individual clients
• Keeps a record of how they cleaned client last time
• Adapt cleaning routine to client, depending on whether they cheated the client the previous time.

Question 32

Why is the bluehead wrasse not predated upon?

Answer 32

Because it performs 20% of the cleaning of fish on Caribbean reefs.

Question 33

Describe the use of harems in a broadcast spawner.

Answer 33

Bluehead wrasse.
Terminal phase male controls a harem of females, defends territory for.
20-50x more successful than ‘sneakers’ - male fish living among females.

Question 34

How much easier was it to catch European eels when played shipment noise?

Answer 34

Took half as long to catch eels.

Question 35

How did European eel respond to ambush predatory threat under shipment noise?

Answer 35

Majority of fish did not startle.

Took greater time for those that did to startle.

Question 36

Describe some physiological changes in European eels experiencing shipment noise.

Answer 36

• Increase in operculum beat rate with ship noise, indiciating increased ventilation rates, therefore increased stress.
• Use more oxygen in the water, indicates increased metabolic rate.
• Loss of lateralisation, lose preference for exploring novel habitats. Indicates change in cognitive ability.