An increase in the world’s populations along coasts is putting a huge amount of pressure on the ocean and reefs as a food supply. Fishing, when done sustainably, will continually ‘restock’ itself. However, destructive fishing methods are greatly used throughout the world which is destroying reefs. Blast fishing, cyanide poisoning and trawling are all methods used with ideas of quick gain rather than future investment. A study done by Hingco & Rivera (1991) found that 70% of the fish caught by sodium cyanice poisoning were captured for use in aquariums and live fish markets such as in Figure 4.
Pet-Soede et al (2000) found that blast-fishing triggered in the water killed or stunned all fish within a 2.5 metre radius per bomb and several bombs would be set off on a particular trip. The fish sink to the bottom as the swim bladder is punctured and are collected using a seine net (Cornish & McKellar 1998). These methods are still used in less developed countries as this could be a fisherman’s only income. However, this is a hugely wasteful way to catch fish as all organisms in that radius are affected either directly or indirectly by killing fish or decreasing the habitat. Sometimes not all fish are collected as the fishermen flee the area to avoid capture by marine police as, fishing using explosive and poison have been banned for over 40 years (Cornish & McKellar 1998). When blast-fishing is used it decreases the overall value of the environment aesthetically, biologically and economically. Sites become less appealing to SCUBA divers and therefore decreasing tourism in the area.
Over-fishing is simply; ‘too many fishermen catching too few fish’ (Kaiser et al. 2005). The fish species being targeted will soon reach a biological capacity where it is difficult to recover with further fishing. Over fishing certain areas is also a huge cause of decrease in the diversity and the resilience of corals to natural threats such as storms and hurricanes (Roberts 1995). Reef systems have delicate predator-prey interactions, therefore they are necessary to investigate the effects humans have on the organisation of communities (Bascompte et al. 2005).