Otters control sea-urchin populations in this kelp-forest food web.
If orcas drove otter numbers to near zero, the most likely cascading effect is:
- Acheck_circle
Urchins increase, kelp decreases (trophic cascade)
- B
Urchins decrease, kelp increases
- C
Kelp doubles due to release from grazers
- D
No change in kelp because urchins eat seals
Explanation
Removal of a top predator releases its prey from control. Without otters, urchins overgraze kelp, causing kelp deforestation.