Defence behavior in fishes

Dedicated to all Zoologists

1. DEFENCE behavior in FISHES BY RAHIM ULLAH REG. ZO220172036 Submitted to : Ms. IRUM GUL Department of Zoology Kohat University of Science and Technology, Kohat-26000 Khyber Pakhtunkhwa, Pakistan

2. How fishes defend themselves??? Fish protect themselves through color camouflage, poisonous spines, stunning shocks and chemicals. Poison injected by teeth, or through barbs or spines is a useful defense employed by catfish and scorpionfish . Some species, such as minnows, warn others in their group when they release a chemical substance into the water. A Red Sea flounder releases a chemical so effective that even sharks avoid them.

3. Fishes protect themselves by several ways, discussed below. Staying in School Schooling is one of the primary ways many fishes help defend themselves from predators. “Big fish eat little fish” so many small fishes gather in schools and they look like a single large creature, and many predators tend to leave large animals alone .

4. Sticking it to ’ Em A variety of fishes use numerous sharp spines and armored scales to help fend off predators. By swallowing a lot of water when alarmed, balloonfishes and pufferfishes can inflate their bodies, erecting a number of very sharp spines. The rigid and sharply pointed spines give an attacker an unpleasant mouthful of “nails and needles” instead of an easy meal.

5. Poisons and Potions Scorpionfishes, lionfishes and stonefishes are equipped with a pair of poison glands at the base of each of their many pectoral spines. When threatened these species can quickly lunge forward and use these spines as venom-injecting needles to repel threats. The reef stonefish is thought to be the most highly venomous fish in the world.

6. On the Fly More than 50 species of flying fishes use their ability to glide above the surface of the ocean to escape predators such as tunas, billfish, sea lions, dolphins, sharks and more. Flying fishes are able to “jump” out of the water and then glide through the air over considerable distances. When spread while airborne, their greatly enlarged pectoral creates an airfoil similar to an airplane wing providing lift and enabling these fishes to glide. Those species that have four “wings” also have enlarged pelvic fins that provide additional lift . Flying fish can glide for at least 325 feet (100 m), and they are occasionally seen as high as 10 feet (3 m) above the surface.

7. Safe at Home Many fishes, including tilefishes , a variety of gobies and jawfishes , reside in self-made burrows to where these fishes retreat when they detect danger. In some cases the burrows are rather elaborate and have several entrances and exits meaning that a predator cannot just watch one opening and be ensured of cornering its prey. Razorfishes don’t require a burrow. They can quickly bury themselves in sandy bottoms.

8. Shock and Awe In comparison with other rays, electric rays are not fast swimmers. Nor are they armed with barbs like stingrays. But they are far from defenseless. As their name suggests, electric rays are equipped with specialized electricity-producing organs that can unleash powerful electric shocks that help these rays protect themselves and stun prey.

9. Mimicry A variety of fishes such as the four eyes butterflyfish use a false eyespot to confuse predators. The big, dark, conspicuous spot is on the back of the fish’s body above, but near the tail. Specialists believe that the eyespot is intended to trick predators into thinking that the fish’s tail is actually its head so the predator is likely to be fooled, the butterflyfish swims when it attempts to evade the predator.