How does the humpback anglerfish attract prey?

2. What species are the most abundant of all vertebrate families?

3. What is orabyssopelagic zone?

4. How does the behaviour of bathypelagic fish differ from the behaviour of mesopelagic fish?

5. Describe the bathypelagic fish.

Read the text and fill in the right words: pressure, inhabit zone, habitat, food, teeth, sperm, predators, male.

The swimbladders of deep sea fish are either absent or scarcely operational, and bathypelagic fish do not normally undertake vertical migrations. Some deep sea fishes have swimbladders which function while they are young and ______ the upper epipelagic zone, but they wither or fill with fat when the fish move down to their adult ______.

The most important sensory systems are usually the inner ear, which responds to sound, and the lateral line, which responds to changes in water _______. The olfactory system can also be important for males who find females by smell. Bathypelagic fish are black, or sometimes red, with few photophores. When photophores are used, it is usually to entice prey or attract a mate. Because _____ is so scarce, bathypelagic ______ are not selective in their feeding habits, but grab whatever come close enough. They accomplish this by having a large mouth with sharp _____ for grabbing large prey.

It is not easy finding a mate in this zone. Some species depend on bioluminescence. Others are hermaphrodites, which doubles their chances of producing both eggs and ____ when an encounter occurs. The female anglerfish releases pheromones to attract tiny males. When a ______ finds her, he bites on to her and never lets go. When a male of the anglerfish species Haplophryne mollis bites into the skin of a female, he release an enzyme that digests the skin of his mouth and her body, fusing the pair to the point where the two circulatory systems join up. The male then atrophies into a pair of gonads. Many forms other than fish live in the bathypelagic ____, such as squid, large whales, octopuses, sponges, brachiopods, sea stars, andechinoids, but this zone is difficult for fish to live in.

Fig. 3 Fish skeletom system

Make questions for the following sentences:

1. Flashlight fish have aretroreflector behind theretina which they use withphotophores to detecteyeshine in other fish.

2. The gulper eel uses its mouth like a net by opening its large mouth and swimming at its prey. It has a luminescent organ at the tip of its tail to attract prey.

3. The black swallower, with its distensible stomach, is notable for its ability to swallow, whole, bony fishes ten times its mass.

4. The widespread fangtooth has the largest teeth of any fish, proportionate to body size. Despite their ferocious appearance, bathypelagic fish are usually weakly muscled and too small to represent any threat to humans.

5. Demersal fish live on or near the bottom of the sea. Demersal fish are found by the seafloor in coastal areas on the continental shelf, and in the open ocean they are found along the outer continental margin on the continental slope and the continental rise.

6. In deep waters, the fishes of the demersal zone, compared to fishes of the bathypelagic zone, are active and relatively abundant."

7. Rattails and brotulas are common, and other well established families are eels, eelpouts, hagfishes, greeneyes, batfishes andlumpfishes.

8. The bodies of deep water benthic fishes are muscular with well developed organs. In this way they are closer to mesopleagic fishes than bathopelagic fishes. In other ways, they are more variable.

9. Photophores are usually absent, eyes and swimbladders range from absent to well developed. They vary in size, with larger species greater than one metre not uncommon.

10. Deep sea benthic fish are usually long and narrow. Many are eels or shaped like eels. This may be because long bodies have long lateral lines. Lateral lines detect low-frequency sounds, and some benthic fishes appear to have muscles that drum such sounds to attract mates.

11. The main diet of deep sea benthic fish is invertebrates of the deep sea benthos and carrion. Smell, touch and lateral line sensitivities seem to be the main sensory devices for locating these.

12. Deep sea benthic fish can be divided into strictly benthic fish and benthopelagic fish.

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