Overfishing

overfishing

harvesting so many fish that there’s not enough breeding stock remaining to replenish the species

fisheries

populations of fish used for commercial fishing

fishery collapse

when overfishing causes 90% population decline. never recover bc decreased biodiversity (of fish AND other species)! inability to find mates, inbreeding depression

fishery collapse economic consequences

lost income for fishermen, lost tourism dollars for communities

factory fishing

highly industrialized, huge vessels use powerful tech to capture fish in huge volumes (process and freeze while catching)

longline

fishing for tuna and swordfish

bottom trawling

dragging large net across ocean floor, leads to bycatch, stirs sediment (increase turbidity), destroy coral reef and benthic communities, similar to clear cutting/strip mining

bycatch

unintended species caught in net

longline fishing

long lines of hooks stretch to catch fish, bycatch

driftnets

nets hung in water to catch fish, ghost netting (nets left behind constantly catching organisms forever), bycatch

as we deplete large predatory fisheries we move down to smaller fish species leading to..

decreased fishery recovery and decrease food supply of marine mammals and seabirds

aquaculture

humans mitigate fishery impact through this by breeding, rearing, and harvesting in marine or freshwater for consumption; raising fish in cages/enclosures underwater

fish farming (aquaculture)

man made tanks/enclosures (catfish, tilapia, salmon, carpet, cod, trout)

mariculture (aquaculture)

marine organisms in open ocean enclosures (flounder, shellfish, oyster, kelp, seaweed)

aquaculture benefits

requires only small amount of water, space, fuel; reduce risk of fishery collapse, doesn’t take up any land

aquaculture negatives

high density →high concentration of waste (e. coli, eutrophication), increase disease risk which transmit to wild pop., non-native species or GMOs to local ecosystem if escape, fed antibiotics which contaminate water via their waste