In a basic fish bioenergetics model, what determines growth?

In a basic fish bioenergetics model, what determines growth?

• A. Light availability alone
• B. Prey diversity only
• C. Energy intake minus routine metabolism and activity costs
• D. Water temperature only

Answer: (C)

Growth in a basic fish bioenergetics model comes from the energy that remains after the fish has paid for its maintenance and activity costs. The fish takes in food and converts some of that into assimilated energy; from this, the routine metabolic needs and any energy spent on movement or other activities are subtracted. The leftover energy is what can be allocated to growth. So, the most direct determinant is the net energy available for production after covering maintenance and activity costs. Light, prey diversity, and temperature influence growth by affecting how much energy is ingested or how much energy is spent, but they do so by changing input and costs rather than constituting the growth term itself.

Growth in a basic fish bioenergetics model comes from the energy that remains after the fish has paid for its maintenance and activity costs. The fish takes in food and converts some of that into assimilated energy; from this, the routine metabolic needs and any energy spent on movement or other activities are subtracted. The leftover energy is what can be allocated to growth. So, the most direct determinant is the net energy available for production after covering maintenance and activity costs. Light, prey diversity, and temperature influence growth by affecting how much energy is ingested or how much energy is spent, but they do so by changing input and costs rather than constituting the growth term itself.