Find the Truth! Mortality caused by fishing may be replaced by juveniles that would not otherwise been recruited to the adult population. Fishing above the MSY is overfishing and will cause a decline in juvenile biomass. Overfishing can often be detected by reduced catches, a reduction in average age of adult fish and slower growth of the fish that do survive.

Find the Truth! Mortality caused by fishing may be replaced by juveniles that would not otherwise been recruited to the adult population. Fishing above the MSY is overfishing and will cause a decline in juvenile biomass. Overfishing can often be detected by reduced catches, a reduction in average age of adult fish and slower growth of the fish that do survive. So what impact does fishing have on fish populations?

What are the environmental impacts of fishing?

What is By-catch? Organisms that are caught unintentionally. They usually die Types include; fish that are too small to sell Surplus to quotas Species of no commercial value Albatrosses caught in long lines Whales/dolphins caught in drift nets species inadvertently caught in trawl nets

Ghost fishing Fish, lobsters etc caught by discarded or lost fishing gear Seabed damage Coral reefs damaged by nets. Foodchain effects Some species become more common if their predators are over-exploited Reduced food supply for predators, increased food supply for competitors. Other Environmental Impacts

The Crown-of-Thorns is a, carnivorous predator that preys on reef coral polyps. They climb onto reef structures, and then extrude their stomach onto the coral. This releases digestive enzymes that allow the starfish to absorb nutrients from the liquefied coral tissue.carnivorouspredator Overpopulation of Crown-of-Thorns has been blamed for widespread reef destruction. The Giant Triton (a mollusc) and the harlequin shrimp attack and feed on Crown-of-Thorns starfish. Some large reef fish, particularly Humphead wrasse, may also prey on the starfish.Giant Tritonharlequin shrimpHumphead wrasse Decline in predator populations (through overharvesting, habitat destruction) has also been offered as an explanation for increasing outbreaks of Crown-of-Thorns starfish. What is the threat from crown of thorns starfish?

The Crown-of-Thorns is a, ___________________that preys on reef coral polyps. They climb onto reef structures, and then extrude their stomach onto the coral. This releases digestive enzymes that allow the starfish to absorb nutrients from the liquefied coral tissue. Overpopulation of Crown-of-Thorns has been blamed for widespread reef destruction. The _____________(a mollusc) and the ____________attack and feed on Crown-of-Thorns starfish. Some large reef fish, particularly__________________, may also prey on the starfish. Decline in _________________(through overharvesting, habitat destruction) has been offered as an explanation for increasing outbreaks of Crown-of-Thorns starfish. What is the threat from crown of thorns starfish?

What are the environmental impacts of fishing? Seabed damage Bycatch Food web effects Ghost Fishing Effects on fish stocks examples explanation Complete a spider diagram to summarise the impacts. Include evidence and explanation