Question

A.) It is estimated that the mature Atlantic herring population today has a biomass (total weight of the population) of approximately 2 million metric tonnes (2 billion kg). If an average adult Atlantic herring weighs 0.125 kg, how many adult Atlantic herring are there in the entire population?

A. 16 million fish
B. 20 million fish
C. 24 million fish
D. 32 million fish

B.) An adult Atlantic herring consumes, on average, 10 g of plankton per day. How much plankton would the adult Atlantic herring population consume in a day?

A. 20,000,000 grams of plankton
B. 15,000,000 grams of plankton
C. 25,000,000 grams of plankton
D. 30,000,000 grams of plankton

C.) If there were a severe reduction of plankton available to the Atlantic herring population, and therefore a 55% decrease in the herring, how many mature Atlantic herring would be supported by the ecosystem?

A. 8 million fish
B. 12 million fish
C. 16 million fish
D. 18 million fish

D.) How many kilograms would that equate to?

A. 1.2 million kilograms
B. 1.6 million kilograms
C. 1.8 million kilograms
D. 2.4 million kilograms

Answer 1

The mature Atlantic herring population today has approximately 16 million adult herring in the entire population. The adult herring population consumes 20,000,000 grams of plankton in a day. If there is a 55% decrease in the herring population, there would be approximately 8 million mature Atlantic herring in the ecosystem, which would weigh approximately 1.2 million kilograms.

Step-by-step explanation:

To find the number of adult Atlantic herring in the population, we need to divide the total biomass of the population by the average weight of an adult herring. The biomass is 2 million metric tonnes, which is equivalent to 2 billion kilograms. Since the average weight of an adult herring is 0.125 kg, we divide 2 billion by 0.125 to get 16 billion adult herring. Therefore, the answer is A. 16 million fish.

To calculate the amount of plankton consumed by the adult herring population in a day, we multiply the number of adult herring by the amount of plankton consumed by each herring. The number of adult herring is 16 million (from the previous question) and each herring consumes 10 grams of plankton. Multiply these two values together to get 160 million grams of plankton. Therefore, the answer is A. 20,000,000 grams of plankton.

If there is a 55% decrease in the herring population due to a reduction in available plankton, we need to multiply the original number of adult herring by 0.45 (100% - 55%). The original number of adult herring is 16 million (from the first question), so multiply 16 million by 0.45 to get 7.2 million. Therefore, the answer is A. 8 million fish.

Finally, to find the weight of the reduced herring population, we multiply the number of herring by the average weight of an adult herring. The number of herring is 8 million (from the previous question) and the average weight of an adult herring is 0.125 kg. Multiply these two values together to get 1 million kilograms. Therefore, the answer is A. 1.2 million kilograms.