Ocean Explorers

Lethrinus spp.

Where it lives: Coral reef

What it eats: Crabs, shellfish and small fish it crunches with strong back teeth

Three true things

• Emperors have thick lips and powerful jaws built for cracking shells.
• Many emperors start life as females and change into males as they grow older.
• They hunt mostly at dawn and dusk, and rest among the coral in between.

Looking after it: Common on Kenyan reefs and caught by handline. Reef fish are slow to replace themselves, so size limits matter.

Scomberomorus commerson

Where it lives: Open water near the reef edge

What it eats: Sardines, anchovies and squid, chased at speed

Three true things

• A kingfish can swim in short bursts faster than most people can cycle.
• It has no swim bladder, so it must keep moving to stay off the bottom.
• Its silver sides carry faint wavy bars that fade the moment it leaves the water.

Looking after it: A fast-growing ocean fish. Healthier stocks than slow reef species, but still fished hard across the region.

Thunnus albacares

Where it lives: The open ocean of the Pemba Channel

What it eats: Small fish, squid and crustaceans

Three true things

• Tuna are warm-blooded — unusual for a fish — which lets their muscles work harder.
• They never stop swimming, not even to sleep.
• A yellowfin tuna can cross an entire ocean in a single year.

Looking after it: Tuna cross borders, so they are managed by countries working together through the Indian Ocean Tuna Commission.

Octopus cyanea

Where it lives: Holes and crevices in the coral reef

What it eats: Crabs, shellfish and small fish

Three true things

• An octopus has three hearts and blue blood.
• Two thirds of its neurons are in its arms, so each arm can partly think for itself.
• It can change colour and skin texture in under a second to vanish against a rock.

Looking after it: Kenyan villages have tried closing octopus grounds for a few months at a time. When the area reopens, the octopus are bigger and there are more of them — a simple idea that works.

Siganus sutor

Where it lives: Seagrass meadows

What it eats: Seagrass and algae — it is a grazer, like a goat of the sea

Three true things

• Rabbitfish have mildly venomous spines, so fishermen handle them carefully.
• They graze seagrass the way cattle graze a field, which keeps the meadow healthy.
• They often swim in pairs and stay together for a long time.

Looking after it: One of the most abundant and fastest-growing fish on this coast, which makes it one of the more sustainable choices.

Epinephelus spp.

Where it lives: Caves and overhangs in the reef

What it eats: Fish and crustaceans, swallowed whole in a sudden gulp

Three true things

• A grouper does not bite its prey — it opens its huge mouth so fast that water rushes in and carries the meal with it.
• Some groupers live for decades and stay in the same cave for years.
• Groupers and moray eels sometimes hunt together, which is rare between different species.

Looking after it: Large groupers grow slowly and gather in the same place to spawn, which makes them easy to overfish. Small ones should be left to grow.

Scarus spp.

Where it lives: Coral reef

What it eats: Algae scraped off coral rock with a beak made of fused teeth

Three true things

• Parrotfish poo is sand. A single big one can produce hundreds of kilos of white sand a year.
• Some sleep inside a bubble of mucus they blow around themselves at night, which hides their smell from predators.
• Many change both colour and sex as they grow up.

Looking after it: Parrotfish keep algae from smothering coral, so a reef with plenty of them recovers faster after bleaching.

Sardinella spp.

Where it lives: Open water, in huge shoals

What it eats: Plankton — tiny drifting plants and animals

Three true things

• A shoal turns and flashes as one because each fish watches only its closest neighbours.
• Sardines are one of the few fish people eat whole, bones and all.
• They are food for almost everything bigger — tuna, kingfish, dolphins and seabirds.

Looking after it: Small, fast-breeding and abundant. Eating small fish puts less pressure on the ocean than eating the big ones that hunt them.

Carcharhinus spp.

Where it lives: Reef edges and open water

What it eats: Fish and squid

Three true things

• Sharks have no bones at all. Their whole skeleton is cartilage, the bendy stuff in your ear.
• Shark skin is covered in tiny tooth-like scales that make it rough as sandpaper.
• Sharks have swum in these oceans since long before there were trees on land.

Looking after it: Many shark species are in serious trouble worldwide because they grow slowly and have few young. Several are protected in Kenya and must never be caught or sold.

Uroteuthis duvaucelii

Where it lives: Open water, near the bottom by day

What it eats: Small fish and shrimp caught with two long tentacles

Three true things

• A squid moves by squirting water — the same idea as a jet engine.
• When frightened it releases ink and jets away behind the cloud.
• Squid have the largest eyes, for their body size, of almost any animal.

Looking after it: Squid live fast and die young — usually within a year — so their numbers recover quickly.