Symbiotic
Relationships
• Mutualism - both benefit
• Commensalism - one benefits
• Parasitism- viruses, bacteria, flatworms,
leeches,
Mutualistic relationships
• Zooxanthellae- in coral, anemones, snails,
& giant clams
• Corals- crabs, shrimp, fish
• Sponges- nitrogen fixing cyanobacteria
• Anemone fish- anemone
• Obligate symbionts- committed, can’t live
without
Relationships between
anemone/fishes
Anemone fish
provide
1. Protection- drive
away other fish
2. Sometimes will
feed host
Anemone
provide
1. Safe place
2. Nest/eggs
brooded under
anemone
Commensal relationships
Pearl fish typically, they live inside clams,
starfish or sea squirts, and are simply
commensal, not harming their hosts.
However, some species are known to be
parasitic on sea cucumbers, living in their
gut and eating their sex organs.
Parrot fish
• Are known for their parrot like beaks which
they scrape algae from coral. This distributes
coral sand, and prevents algae from choking
coral. Can produce 90 Kg of sand a year. To
keep up teeth grow continuously.
• Maneuver with pectoral fins.
• Excrete mucus cocoon at night to hide scent.
• Parrot fish must be protected to protect the
reef
Parrotfish
Damsel fish
• Brightly colored, territorial fish which
include anemone fish some defend an
area that grows a mat of algae, which they
feed on. (garden of algae)
Hawaiian Domino Damselfish
Damselfish
Types of reef
• 1. Fringing Reefs
• 2. Barrier Reef
• 3. Atoll
Types of Reefs:
1. Fringing Reefs:
• Simplest kind
• Grow in narrow band/ fringe along shore
• Most vulnerable to pollution runoff
2. Barrier Reef:
• Farther from shore (up to 60 miles)
• Separated from shore by lagoon
• Sand islands form (sand cays)
• Spur and groove (buttresses) coral with sand channels form in windward side.
• Great Barrier Reef/ Belize
3. Atolls:
• Ring of reef (or cays) surrounding lagoon
3. Atolls:
•Can be far from land and 1,000 meters deep
• Darwin solved the puzzle on how it formed fringing reef
growth on a subsiding island (volcano).