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CONTINENTAL SHELF - Coggle Diagram

- - - - Damage is mostly caused by discarded gear, which may remain on a reef for decades, causing acute and chronic degradation. Fishing gear is discarded by fishermen who are unable to retrieve ropes, when lines or nets become entangled on the sea-bed, or when breakage occurs. Nets in particular also become entangled on coral reefs after having become lost in storms or heavy seas. Other fishing gear, for example that which is judged by fishermen to be beyond repair, is simply dumped at sea by fishermen. Some of this gear is carried by currents and wave action onto coral reefs.
        
        A total of 87 abandoned gill nets or fragments of gill nets were found on coral reefs during the survey. Of these 21 % were thought to have been lost or aban-doned less than 1 year previously. A further 29% were lost or abandoned 1 to 5 years previously and the remaining 51 % had been on the reefs for more than 5 years
        
        Sixteen percent of the nets, including mono-filament
        nets, were found to contain live or recently dead
        fishes, crustaceans, molluscs turtles, cetaceans or
        other marine wildlife, that had become entrapped
        within them following the abandonment of the nets
        
        Degradation of coral communities as a result of
        abandoned nets allows invasion by algal species, which quickly out-compete corals and prevent coral larval settlement.
        
        Macro-photography reveals the effect of nylon
        filament on living coral tissue. The coral polyps surrounding the filament become damaged and feeding tentacles remain retracted in the calyx, impairing the normal function of the colony.
  - - - analysis of plastic debris in the oceans has shown that it can carry many bacteria, including some pathogens that cause coral disease
      - According to them, plastic debris has a direct effect on the development of disease by causing physical damage to coral tissue. In addition, by carrying pathogens within and between reefs, they promote their spread and increase the risk of infection.
      - another study suggests that corals voluntarily ingest plastic because they are attracted by its taste, probably because of the chemical additives present in plastics (chemoreception mechanism)