The Human Impact on the Ocean | cooking lobster tails

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The Human Impact on the Ocean

The main fishing methods.

Commercial fishing accounts for 90% of the world catch. The main fishing methods have changed over time since commercial fishing really began in the 15th century. The advent of freezer ships after the Second World War has increased the ability of vessels to stay out fishing and improved fishing gear, longer lines, larger nets and more effective ways of locating fish have all contributed to overfishing. In modern commercial fishing just six species make up over half the catch ( cod, herring, anchovies, sardine, pollack and mackerel ).  Modern commercial fishing relies on several main methods. Purse seiners, trawlers, oceanic long liners, and drift nets.

Let us take each of these methods in turn. Purse seine nets encircle a whole shoal of fish and the net is then tightened like a purse string. This method is effective for sardines, anchovies and tuna. Trawling is the method used for dimersal fish. Here trawl nets are dragged along the bottom of the sea , usually on the continental shelf and these nets taper to the cod end. The nets are then drawn in. This method is effective for cod, hake, haddock, shrimp, prawn and lobster. Next we have the longliners. This is basically a series of lines with hooks. Some lines can be 30 kilometers in length. This method is effective for tuna, Marlin and billfish. Drift nets are another method used to catch fish. These are vast nets sometimes tens of kilometers long but they entangle many unwanted species. Trammel nets have a similar effect.

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