[问答题]
Figure: Capture fisheries by region
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Capture fisheries involve species that are generally higher up in the food chain, often feeding as secondary consumers. Suggest two possible impacts overfishing of these species might have on the ecosystems they belong to.
参考答案:
Sample answer:
1. Removing a large number of secondary consumers such as tuna or salmon could lead to an increase in their prey species, due to a lack of predation.
2. If these species become too numerous and are primary consumers, they could cause a reduction in the ecosystem's producers.
Any two of the following is OK:
a. Removal of these species could lead to overpopulation of the prey species they consume.
b. Competitors of the prey species would face increased competition as the numbers of the prey species increase.
c. Producers could be overgrazed if primary consumers become overpopulated due to lack of predation.
d. Other secondary consumers may change their preferred food if they experience decreased competition due to the removal by overfishing.
e. Tertiary consumers in these ecosystems could die off due to a lack of food (e.g. Bears who eat salmon).
本题详细解析:
