Increase in human population causes an increased demand for fish. Some species of fish have been caught in such large numbers that their populations have drastically decreased. These species are over-fished.
Modern fishing methods may lead to indiscriminate removal of marine lifeforms (ie immature organisms or unwanted species eg turtles). Examples include the
1. use of large drift nets which are nets left to drift freely in seas. These nets trap almost everything in their path,
2. dredging which involves scraping the seabed and in the process destroys coral reefs and organisms that live on the seabed,
3. trawling that involves dragging large fishing nets along the bottom of the seabed, trapping marine life indiscriminately and
4. cyanide fishing that involves squirting a poison, cyanide into the water around coral reefs. The cyanide stuns reef fish and makes them unable to swim properly. The fishermen then capture the fish and sell them as pets. Explosives such as dynamites are also used to stun and catch reef fish. Both cyanide and explosives kill corals and other reef organisms.
Effects:
Some species of fish may be removed faster than they are replaced. Faster extinction.
Young fish that are caught may not have a chance to grow and reproduce. Fish populations will decrease.
Watch this video on drift net fishing.
Questions
1. What is drift net fishing?
2. What are some harmful effects of drift net fishing?
URL: http://youtube.com/watch?v=DL3cm8a1P6c
Watch this video on dredging.
Questions
1. What is dredging?
2. What are some harmful effects of dredging?
URL: http://youtube.com/watch?v=E2OgJMz2tRE
Dynamite Fishing
Visit this Youtube link: http://www.youtube.com/watch?v=FHrlXY9Gd6c
One point to consider:
Is dynamite fishing safe for the fishermen?
Drift-Net fishing
1. What kind of fish species do fishermen target on when they carry out drift net fishing?
2. What is the percentage of flora and fauna removed each time the drift net is used?