Fisheries

Historically fisheries management has mostly failed to sustainably develop and manage fisheries. In the past fisheries management focused on individual management for each type of target fish (what scientists called a “single species” approach focus). For example, management rules and advice did not worry about what impact harvesting the target fish had on other fish, habitats such as the ocean floor, or other species such as turtles or seabirds. Managers and scientists assumed that if there were any impacts, the target fish species would not be affected. We now know that this is not true. As pressure on resources and the ecosystem increases, the problems of this single-species approach have become more obvious.

Impacts of Fishing

All fishing methods have some degree of environmental impact. This could be something as simple as a seagull becoming entangled by apiece of discarded nylon fishing line from a recreational angler, to the destruction of centuries-old deep sea corals by heavy trawling gear. In order to decide whether a particular fishing method has unacceptable levels of environmental harm we need to consider the following factors:

Bycatch and incidental mortality

Bycatch: - How successful is a fishing method at catching what it intends to catch? If a certain type of gear is very target specific it can be considered a better fishery than one where a lot of the catch is wasted (e.g. tuna pole fishing for yellowfin tuna and albacore vs. bottom trawling for prawns). Bycatch is the term used to describe all organisms that are inevitably caught when fishing for a specific species or group...learn more

Foodwebs

Foodwebs: - All living things depend on one another to survive. Removing key species from the foodweb can cause an imbalance in the entire ocean ecosystem, as it may disrupt other foodwebs which rely on these key species to survive. Many marine ecosystems are particularly vulnerable to the removal of the dominant predators which occur at the top of the food chain such as sharks, dolphins and seabirds. Without these predators regulating the numbers of animals lower down...learn more

Habitat damage

This refers to the physical destruction of marine habitats. Some marine habitats are more fragile than others and can be permanently damaged from fishing gear, such as trawling over a coral reef. Destroying bottom habitats not only reduces the number of refuges or shelters for fish but disrupts the overall productivity of the system. Habitat damage can include human activities other than fishing, for example, undersea mining, or developments in or near estuaries that destroy important nursery areas for many...learn more

Other Concerns

Other Concerns - Fisheries do no occur in isolation and it is not just the impacts of the fishing methods that make some fisheries unsustainable. There are a number of important economic, political and social issues which are also at play in most fisheries. Local concerns South African fish stocks have also endured their share of abuse and exploitation over the past century. The most valuable local resource is hake, which consists of two species,...learn more