Reef Fish Feeding

1. Odyssey Expeditions Reef Fish Feeding Odyssey Expeditions – Reef Fish Feeding

2. Introduction • Fishes feed on plants, animals, plankton, and detritus • Feed at night (nocturnally) or during day (diurnally) • Mouth shape and size determines prey type • Diets can change throughout life • Generally all start out as planktivores during larval stage in water column • As juveniles settle on reef they change to adult diet • Diets are not written in stone, most fishes switch prey when something else is abundant (called optimal foraging theory) Odyssey Expeditions – Reef Fish Feeding

3. Odyssey Expeditions Odyssey Expeditions Introduction • Most fishes forage by day • Low light hours when most feeding occurs • Vision a key to daytime foraging Odyssey Expeditions – Reef Fish Feeding

4. Feeding Categories • Herbivores – Consume plant material (algae, seagrass) • Carnivores – Feed on animals (inverts, plankton, fishes) • Invertebrate feeding – primary prey are invertebrates • Piscivores – fishes are the primary prey • Planktivores – prey upon planktonic creatures • Detritivores – Consume decomposing plant and animal matter Odyssey Expeditions – Reef Fish Feeding

5. Feeding Behaviors • Specialist • Single food source • When food source scarce they must change or perish • Generalist • Feed on a variety of foods (no preference) • Generally stay in their feeding category • Opportunist • Feed on anything regardless if in feeding category or not Odyssey Expeditions – Reef Fish Feeding

6. Odyssey Expeditions Odyssey Expeditions Herbivores • Small number of herbivorous species • Large population sizes • Common families (parrotfish, damselfish, surgeonfish) • Mostly found in water < 30’ (more light = more algae) • Consume large amounts of algae • Healthy populations consume most of daily algae production Odyssey Expeditions – Reef Fish Feeding

7. Odyssey Expeditions Odyssey Expeditions Herbivores • Highly maneuverable • Swim with pectoral fins • Many have compressed bodies • May contain organisms in gut to enable efficient plant material digestion • Incisor-like teeth makes feeding on algae easier (may be fused to form beak like structure) Odyssey Expeditions – Reef Fish Feeding

8. Herbivorous Feeding Strategies • Nomadic Feeders • Scour over large areas of the reef in search of algae • Parrotfishes, surgeonfishes • Sedentary Feeders • “Farm” mats of algae • Damselfishes Odyssey Expeditions – Reef Fish Feeding

9. Odyssey Expeditions Nomadic Feeders • Parrotfishes • Use beaklike teeth to scrape algae off hard surfaces • Large amounts of calcium carbonate is taken in along with algae • Can excrete over 1 ton of sand per year Odyssey Expeditions Odyssey Expeditions – Reef Fish Feeding

10. Odyssey Expeditions Odyssey Expeditions Nomadic Feeders • Surgeonfishes • Mouths enable them to pluck algae efficiently • Feed alone or in large number • Can overwhelm damselfishes and therefore eat their farm-fresh algae Odyssey Expeditions – Reef Fish Feeding

11. Odyssey Expeditions Odyssey Expeditions Sedentary Feeders • Damselfishes • Most abundant • Aggressively guard mats of algae from other herbivores • Can be aggressive towards divers Odyssey Expeditions – Reef Fish Feeding

12. Herbivorous Fishes • Blennies • Damselfish • Gobies • Mullets • Chubs • Surgeonfish • Triggerfish Odyssey Expeditions – Reef Fish Feeding

13. Odyssey Expeditions Odyssey Expeditions Planktivores • Most larval/juvenile fishes are planktivores • Planktivores continue this feeding type in adulthood • Water column yields the most plankton • Many have protrusible upturned mouths • Good eyesight • Long gill rakers allow them to strain plankton from water. Odyssey Expeditions – Reef Fish Feeding

14. Odyssey Expeditions Odyssey Expeditions Planktivores • Quick, schooling, and/or large fishes feed up in the water column • Chromis, creole wrasse, manta ray • Generally the smaller fishes school in large #’s for protection (silversides) • Slower fishes feed just outside their hiding places • Yellowhead jawfish, garden eel, fairy basslet, sweepers Odyssey Expeditions – Reef Fish Feeding

15. Cardinalfish Garden eel Jawfish Manta ray Silversides Sweepers Bicolored Damselfish Blue Chromis Brown Chromis Creole Wrasse Blackbar Soldierfish Planktivorous Fishes Odyssey Expeditions – Reef Fish Feeding

16. Odyssey Expeditions Odyssey Expeditions Invertebrate Feeding Carnivores • Excellent maneuverability • Good close-up vision (inverts excellent at camouflage) • Mouth types designed for specific prey • Typically hunt alone, no schooling (avoids competition for limited resource but riskier) • Rely on other defenses (spines-porcupine fish, body plates-trunkfish, broad bodies-angelfishes) Odyssey Expeditions – Reef Fish Feeding

17. Odyssey Expeditions Odyssey Expeditions Invertebrate Feeding Carnivores • Goatfish use chemical sensing barbels to locate prey in sand • Spotted eagle rays use their dental plates to crush shells • Trunkfish shoot a jet of water at the prey to uncover it Odyssey Expeditions – Reef Fish Feeding

18. Odyssey Expeditions Odyssey Expeditions Invertebrate Feeding Carnivores • Angelfishes feed primarily on sponges • Prefer those will less spicules • Secrete layer of mucus to protect stomach from spiclules • Only a few bites are taken from each sponge so it does not kill the sponge. Odyssey Expeditions – Reef Fish Feeding

19. Odyssey Expeditions Odyssey Expeditions Invertebrate Feeding Carnivores • Butterflyfishes use their tubular mouths to pluck feather duster and calcareous tube worms from their tubes • Surgeonfish and parrotfish remove coral polyps in their quest for algae Odyssey Expeditions – Reef Fish Feeding

20. Odyssey Expeditions Odyssey Expeditions Invertebrate Feeding Carnivores • Night predators • Most invertebrate activity at night • Difficult to see • Rely on touch, taste, smell and lateral lines • Large mouths open wide and create suction to capture prey • Many have large eyes to help vision • Generally red or muted in color (camouflage for the night) • Grunts and snappers move to seagrass beds to feed at night, during the day they hang on the reef in schools Odyssey Expeditions – Reef Fish Feeding

21. Angelfish Bigeye Blennies Cardinalfish Cowfish Trunkfish Drums Eagle Ray Filefish Flounder Goatfish Grunts Hamlet Hawkfish Goliath Grouper Moray Porcupinefish Sand Tilefish Snapper Stingray Triggerfish Wrasse Invertebrate Feeding Carnivores Odyssey Expeditions – Reef Fish Feeding

22. Piscivores • Foraging strategies • Pursuit • Jacks, sharks, barracuda, tarpon • Stalking • Trumpetfish, • Ambush • Lizardfish, toadfish, grouper, flounder Odyssey Expeditions – Reef Fish Feeding

23. Odyssey Expeditions Odyssey Expeditions Pursuit Predators • Begin attack from great distance • Typically already on the move • Use speed to capture prey • Streamlined body enables them to swim large distances around the reef more efficiently in search of prey • Large eyes • Silvery bodies aid in open water camouflage Odyssey Expeditions – Reef Fish Feeding

24. Odyssey Expeditions Stalking Predators • Begin attack from stationary position • Maneuver close to prey in order to spring attack • Caudal fin has large surface area in order to provide quick burst of speed for strike • Many fishes have expandable circular jaws that enables them to suck in prey • Trumpetfishes camouflage with gorgonians to enhance their stalking success Odyssey Expeditions – Reef Fish Feeding

25. Odyssey Expeditions Odyssey Expeditions Ambush Predators • Wait for prey to come to them • Often well camouflaged • Groupers and others create a negative pressure inside mouth area by expanding gill covers, then the mouth opens and brings in prey and water. • Flounders are the snipers of the ambush predators • They lay camouflaged on the bottom and quickly capture prey with their sharp teeth Odyssey Expeditions – Reef Fish Feeding

26. Barracuda Black Hamlet Coronetfish Spotted Moray Frogfish Graysby Grouper Jack Lizardfish Mackerel Scorpionfish Snapper Soapfish Trumpetfish Tuna Piscivorous Fishes Odyssey Expeditions – Reef Fish Feeding

27. Odyssey Expeditions Detritivores • Decomposing plant and animal matter • Few found on the reef • Some herbivores take in detritus by accident when feeding on plant material • Mullets and some gobies Odyssey Expeditions – Reef Fish Feeding

28. Different Foraging Behaviors • Nuclear Hunting – two or more species work together in order to capture prey • Shadowing – one species follows another in close proximity trying to blend in with the other Odyssey Expeditions – Reef Fish Feeding

29. Odyssey Expeditions Odyssey Expeditions Nuclear Hunting • Common for Eels and groupers • Eels will go into holes in the reef while the grouper will wait outside the hole • The prey has two choices: • 1) They can stay in the holes and take its chances with the eel • 2) Escape the eel by exiting the hole and take its chances with the grouper on the outside Odyssey Expeditions – Reef Fish Feeding

30. Odyssey Expeditions Odyssey Expeditions Shadowing • Trumpetfish and bar jacks are seen doing this the most • These fish hang just above the shadowed fish • This camouflage hopefully enables it to get closer to unsuspecting prey Odyssey Expeditions – Reef Fish Feeding

31. Resources • Deloach, Ned and Paul Humann. Reef Fish Behaviour: Florida Caribbean Bahamas. Florida: New World Publications, Inc., 1999 • Humann, Paul and Ned Deloach. Reef Fish Identification: Florida Caribbean Bahamas Florida: New World Publications, Inc., 1999 • McGinley, Mark. Caribbean Reef Fish Foraging. 2006 Odyssey Expeditions – Reef Fish Feeding