Over fishing by, abdal rahman malikPresentation Transcript
CONTENTS What is overfishing? Consequences Global Levels of Fish Catch Rising Down the Food Chain Bycatch Harmful Methods of Fishing Bottom-Trawling No Take Zones Aquaculture Bibliography
WHAT IS OVERFISHING? Catching too much fish for the system to support by reproduction. When people catch fish faster than the fish can repopulate. On a global scale we have enough fishing capacity to cover at least four Earth like planets.
CONSEQUENCES If overfishing continues, fish populations will be reduced even more, no matter what measures are taken. Overfishing not only depletes the fish but seriously harms marine environment. Because the fish population has decreased so much, many other species have been placed at risk because they now lack their major food source.
GLOBAL LEVELS OF FISH CATCH Fish Stocks: o 52% of fish stocks are fully exploited o 20% are moderately exploited o 17% are overexploited o 7% are depleted o 1% is recovering from depletion Between 1950 and 1994, the ocean fishing industry increased the total catch by 400%. Global Fish Stocks are expected to Collapse by 2050 at Current Exploitation Rates. THE CURRENT LEVEL OF GLOBAL FISH CATCH IS IN NO WAY SUSTAINABLE!!!
GLOBAL LEVELS OF FISH CATCHThe graph points out that current levels of fishing are obviously
FISHING DOWN THE FOOD CHAIN Cause: Commercially valuable, bigger, slower growing species have been overfished. (e.g., tuna, cod, snapper) Effect: They target large quantities of smaller species of fish with less commercial value. (squid, sardines, oysters, mussels, and shrimp) Less predatory pressure. Less competition for food.
BYCATCH Living creatures caught unintentionally by fishing gear. Unlike target species, bycatch is unwanted and often unused. Bycatch may be kept or sold. Might be thrown back as discard if not usable. Handling and exposure sometimes injure the bycatch, which may die after being discarded.
HARMFUL METHODS OF FISHING Gillnetting – A invisible to fish fine-filament net used for capturing mainly salmon, cod and sardine. Damages other species. Cyanide fishing – Cyanide is used to stun and capture live coral reef fish. Cheap and effective but illegal.
HARMFUL METHODS OF FISHINGExplosive fishing – theuse of dynamite or otherexplosives to kill fish.Causes for majordestruction of reef. Long-line fishing – long baited hooks used to catch swordfish, tuna, sharks, and turtles.
BOTTOM-TRAWLING Dragging huge, heavy nets along the sea floor. Large metal plates and rubber wheels attached to these nets move along the bottom and crush nearly everything in their path. Water life forms are very slow to recover from such damage.
NO-TAKE ZONES Preserved areas where species are protected. Fishing or catching of other marine animals is prohibited. Help species regenerate, to restore population. Helps species which are not included in no- take zones to restore population.
AQUACULTURE The farming of aquatic organisms – keeping them under controlled conditions. Reduces the worlds dependence on wild stocks of fish. Helps to feed the worlds growing population. Negative impact on wild species.