Question 1
Figure Global trends in the world's marine capture fishery stocks, 1974-2019
Question (a)
Outline two reasons for the change in overfished stock between 1974 and 2019, as shown in Figure.
Increased marine capture/overfishing because:
a. Increased population increasing the demand for food;
b. Increased demand in fish by consumers (because it fashionable/healthy);
c. Increased use of fish for animal feed/aquaculture;
d. Increased of subsidies/economic incentives to promote more fishing;
e. More intensive/unsustainable fishing technologies / e.g. long-lines/trawling/gill nets/satellite imaging;
f. reduced MSY due to lower reproductive potential/dwindling fisheries (positive feedback of past fishing pressure);
Note to examiners: No credit unless points imply an increase in marine (over)fishing
Question (b)
Evaluate a management strategy for capture fisheries that could be used to reduce the levels of unsustainable fishing from 2019 as shown in Figure.
Valid strategy that could increase sustainability [1 max]
One mark per outlined strength [2 max]
One mark per outlined weakness [2 max]
Valid balanced conclusion [1 max]
Note to examiners: Credit the evaluation of any one valid strategy, if more than one, award the highest marked. See examples below:
Example Strategy:
a. Use quotas/fish at/below maximum sustainable yield;
Strengths [2 max]:
b. Setting quotas below maximum sustainable yield reduces the amount of fish caught;
c. Allows fisheries re-stocking/gives time for fish to breed;
d. Forces regular data collection allowing informed management decisions;
Weaknesses [2 max]:
e. Difficult/expensive to monitor or enforce quotas/types of fishing gear/no fishing zones;
f. Difficult to estimate MSY / If MSY is overestimated the stock will be overfished;
g. MSY ignores system complexity/role of the organism;
Marking guidance:
Award one mark for a balanced conclusion;
Ex. Although marine protected areas can be difficult to monitor, if done successfully it promotes biodiversity and increases fish stocks.
Example Strategy:
h. Restrict types and sizes of fishing gear/mesh sizes;
Strengths [2 max]:
i. Allows fisheries re-stocking/gives time for fish to breed;
j. Having larger mesh sizes allows young fish to escape;
k. Decreases bycatch/capture of non-target species;
I. No trawling decreases habitat destruction;
Weaknesses [2max]:
m. Difficult to enforce and monitor on the sea;
n. Larger mesh size may still allow bycatch of larger species;
o. Might decrease income for fishermen;
Award one mark for a balanced conclusion;
Ex. Gear restrictions are an important tool in protecting small fish and fragile habitats, however, they are incapable of controlling the quantity of fishing effort or the total catch.