Question

scientists believe that green crabs, originally from europe, reached u.s. shores in the mid - 1800s after riding across the atlantic in the ballast water on ships. once here in north america, they traveled to maine, where they have been present for more than a century. green crabs are a non - native, or invasive species, organisms that have been transported via human activities and introduced to locations in which they previously did not occur. the green crab population in some areas of maine has increased dramatically in recent years, and they have been feeding on shellfish resources such as blue mussels and soft - shell clams, threatening the states third - largest wild fishery. the increase in the green crab population has coincided with an increase in ocean temperatures. a similar cycle occurred in the early 1950s when the ocean temperatures rose and the green crab population increased, devastating the soft - shell clam resource in maine. what can be done to mitigate the environmental impact of this invasive species? select all that apply.
a incentivize green crab trapping and removal programs.
b introduce poisons to green crab habitats to reduce their population.
c reduce water temperatures in areas with large green crab populations.
d relocate green crabs to other areas of the state with a smaller population.
e use fencing as a method of excluding green crabs from valuable bivalve shellfish areas.

Explanation:

• Option A: Incentivizing trapping and removal programs can directly reduce the green crab population, which is a common and effective method for dealing with invasive species.
• Option E: Using fencing to exclude green crabs from valuable bivalve shellfish areas can protect the local fishery resources.

• Option B: Introducing poisons may have negative impacts on the entire ecosystem, not just the green crabs. It can harm non - target species and disrupt the ecological balance.
• Option C: Reducing water temperatures in large areas is not a practical or feasible solution. Ocean temperatures are influenced by large - scale climate factors and cannot be easily manipulated in a local area.
• Option D: Relocating green crabs to other areas just spreads the problem. They will likely cause the same negative impacts in the new location.

Answer:

A. Incentivize green crab trapping and removal programs.
E. Use fencing as a method of excluding green crabs from valuable bivalve shellfish areas.