Page 340 - (DK) Ocean - The Definitive Visual Guide

338 ANIMAL LIFE

Reproduction

The majority of bony fish, when mature, simply shed their eggs and sperm MOUTH BROODING
directly into the sea, where fertilization takes place. The eggs develop When a female
and the larvae hatch while drifting on ocean currents. Death rates of jawfish has laid
eggs and larvae are high, so many eggs are laid—up to 100 million by the her eggs, the male
collects them
giant ocean sunfish. Once the larvae have grown to juvenile fish, they into his mouth to
often congregate in nursery grounds in sheltered estuaries and bays. In keep them safe. He
contrast to most oceanic fish, many coastal bottom-living species are able will not feed until
to protect their offspring, so they lay fewer, larger eggs, often hiding them the eggs hatch and
the fry disperse.
or caring for them until they hatch. Some have evolved elaborate forms
of care, such as mouth brooding.

SEX CHANGE IN THE CUCKOO WRASSE

1 Like most wrasse, cuckoo wrasse 2 Some older females develop the 3 At the next spawning season, a
have a complex reproductive pattern blue-and-orange pattern of males sex-changed male acquires vibrant colors
featuring sex change. The majority of and change sex after about seven years and courts all females in his territory,
eggs develop first into pink females. of age. Others remain female. fertilizing their eggs (see p.369).

Hunting and Protection

All fish must eat and in doing so may expose themselves to the risk of
being eaten if they come out into the open to forage. Their ultimate aim
is to survive long enough to reproduce successfully and so pass on their
genes to the next generation. Bony fish have evolved many ingenious
methods for catching prey and defending themselves against predators.
Camouflage is an effective strategy and can serve to hide a fish, both
from its predators and from its prey. Color patterns can also deceive,
and butterflyfish use false eye patterns to fool
predators into lunging for their tail end. In the
CAMOUFLAGE
Scorpionfish employ color, crowded environment of a coral reef, many
shape, and behavior in a small fish protect themselves with spines. Filefish
combined camouflage erect a dorsal spine and lock it into position,
strategy. Experts at keeping thereby preventing larger fish from swallowing
still, they can strike with
lightning speed if a small them. Out in the surface waters of the open
fish strays within reach. ocean, there is nowhere to hide, and many
small fish live in shoals for safety. Predators find
it difficult to pick out a target as the
shoal moves and swirls. Although
the shoal is conspicuous, it is
safer for each individual to
join than to swim alone.

OCEAN LIFE SHOALING SHADOW-HUNTING

Even predatory fish need protection from
Trumpetfish often shadow predatory
larger predators, especially when young.
fish when they hunt, since the larger fish
Barracuda juveniles live in shoals during
will often flush out suitable prey. This
the day, while most adults hunt alone.
trumpetfish has chosen to swim with a
Nassau grouper similar in color to itself.