The big-beaked, rock-munching fish that protect coral reefs - Mike Gil
-
0:07 - 0:13As the sun rises over a quiet coral reef,
one animal breaks the morning silence. -
0:13 - 0:16Named for their vibrant scales
and beak-like teeth, -
0:16 - 0:23these parrotfish are devouring
a particularly crunchy breakfast: rocks. -
0:23 - 0:27It may not be immediately clear
why any creature would take bites -
0:27 - 0:28out of the seafloor.
-
0:28 - 0:33But the diet of these flashy foragers
actually plays a key role -
0:33 - 0:36in defending the coral reef’s
complex ecosystem. -
0:36 - 0:40Massive coral reefs
begin with tiny coral larvae, -
0:40 - 0:43which settle on the seafloor’s
hard surfaces -
0:43 - 0:46and metamorphasize into coral polyps.
-
0:46 - 0:50Over time, these polyps
generate rock-like skeletons -
0:50 - 0:52made of calcium carbonate.
-
0:52 - 0:56Together, colonies of polyps produce
large three-dimensional structures, -
0:56 - 1:00which form the basis
of an underwater metropolis. -
1:00 - 1:03These coral complexes are full
of nooks and crannies -
1:03 - 1:06that house and protect
countless life forms. -
1:06 - 1:11Even though coral reefs occupy less than
one percent of the ocean floor, -
1:11 - 1:16these dense ecosystems are home to more
than twenty-five percent of marine life. -
1:16 - 1:22Many fish use corals as shelters for
sleeping and to hide from large predators -
1:22 - 1:25between their trips foraging for seaweed.
-
1:25 - 1:29As the primary food source for many
of the reef’s fish and invertebrates, -
1:29 - 1:32seaweed is vital to this ecosystem.
-
1:32 - 1:35But in high densities,
seaweed can become problematic, -
1:35 - 1:37and even lethal to corals.
-
1:37 - 1:42Seaweed grows on the same hard open
surfaces that coral larvae rely on, -
1:42 - 1:47and their growth prevents new coral
from settling and expanding. -
1:47 - 1:52These competitors have also evolved
a variety of ways to kill existing corals, -
1:52 - 1:54including smothering and abrasion.
-
1:54 - 1:58Some seaweed species
even engage in chemical warfare— -
1:58 - 2:02synthesizing compounds
that destroy coral on contact. -
2:02 - 2:04This is where parrotfish come in.
-
2:04 - 2:08Like many reef fish,
these colorful creatures eat seaweed. -
2:08 - 2:10But unlike their neighbors,
-
2:10 - 2:15parrotfish can completely remove
even the tiniest scraps of seaweed -
2:15 - 2:16from the ocean floor.
-
2:16 - 2:21Their so-called beak is actually a mosaic
of tightly-packed teeth -
2:21 - 2:24which can scrape and grind rock,
-
2:24 - 2:29allowing them to consume every bit
of seaweed covering a stony surface. -
2:29 - 2:32This helps parrotfish reach seaweed
other fish can’t consume, -
2:32 - 2:36while simultaneously clearing out
open space for new corals -
2:36 - 2:40to settle and existing colonies to expand.
-
2:40 - 2:44Eating rocks is just one way parrotfish
help manage seaweed. -
2:44 - 2:46Through a dynamic system
of social networks, -
2:46 - 2:51parrotfish can convey information
to other coral dwelling fish. -
2:51 - 2:56Each fish’s presence and simple routine
behaviors produce sensory information -
2:56 - 2:59that nearby fish can see, hear, or smell.
-
2:59 - 3:03They can even detect changes in water
pressure produced by their neighbors -
3:03 - 3:06using a special sensory organ.
-
3:06 - 3:10All these factors can inform
the behavior of nearby fish. -
3:10 - 3:14For example, a fish safely entering
an open feeding ground -
3:14 - 3:17and not getting attacked
means it’s safe to forage. -
3:17 - 3:22Conversely, a fish rapidly leaving
a location can provide an early warning -
3:22 - 3:24that a threat is approaching.
-
3:24 - 3:26By simply trying to stay alive,
-
3:26 - 3:30these reef fish can incidentally help
their neighbors survive— -
3:30 - 3:33and more of these fish
means less seaweed. -
3:33 - 3:36Unfortunately, human activities
over the last several decades -
3:36 - 3:40have disrupted almost every part
of this complex system. -
3:40 - 3:44In many coral reefs, overfishing
has reduced the number of parrotfish, -
3:44 - 3:49as well as other seaweed eaters,
such as surgeonfish and rabbitfish. -
3:49 - 3:51This has led to unchecked seaweed growth,
-
3:51 - 3:55which threatens to degrade
entire coral reefs. -
3:55 - 3:58The parrotfish that remain
live in much smaller communities. -
3:58 - 4:01Their reduced numbers
can weaken their social network, -
4:01 - 4:06making surviving fish more timid
and less effective at controlling seaweed. -
4:06 - 4:11Today, climate change and pollution
are lowering coral’s natural defenses -
4:11 - 4:13while contributing to runaway
seaweed growth— -
4:13 - 4:17leaving reef ecosystems
more fragile than ever. -
4:17 - 4:21Our reefs are vitally important
to both marine and human life. -
4:21 - 4:26Their unparalleled biodiversity offers
unique opportunities for ecotourism, -
4:26 - 4:29sustainable fishing,
and scientific research, -
4:29 - 4:34while their rocky structures guard
coastlines from waves and storm surges. -
4:34 - 4:37Fortunately, continued research
into reef species -
4:37 - 4:41like the quirky and critical parrotfish
can inform new strategies -
4:41 - 4:44for preserving these essential ecosystems.
- Title:
- The big-beaked, rock-munching fish that protect coral reefs - Mike Gil
- Speaker:
- Mike Gil
- Description:
-
View full lesson: https://ed.ted.com/lessons/the-big-beaked-rock-munching-fish-that-protect-coral-reefs-mike-gil
As the sun rises over a quiet coral reef, one animal breaks the morning silence. Named for its vibrant scales and beak-like teeth, the parrotfish devours a particularly crunchy breakfast: rocks. Why would any creature take bites out of the seafloor? Mike Gil explores how these quirky and flashy foragers play a key role in defending the essential coral reef ecosystem.
Lesson by Mike Gil, directed by Franz Palomares.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:45
TED Translators admin edited English subtitles for The big-beaked, rock-munching fish that protect coral reefs | ||
Elise Haadsma approved English subtitles for The big-beaked, rock-munching fish that protect coral reefs | ||
Elise Haadsma accepted English subtitles for The big-beaked, rock-munching fish that protect coral reefs | ||
lauren mcalpine edited English subtitles for The big-beaked, rock-munching fish that protect coral reefs |