Question 1: Define a trophic level and describe its role in an ecosystem.

Answer: A trophic level is a position in a food chain, representing organisms that share the same feeding mode. It helps understand energy flow and ecological balance.

Question 2: Explain how overfishing at higher trophic levels can affect the entire ecosystem.

Answer: Overfishing higher trophic levels reduces predator populations, which can lead to an increase in prey species, disrupting food chain balance and causing ecosystem instability.

Question 1: The biomass of a fish population at trophic level 3 is 500 kg. If the energy transfer efficiency between trophic levels is 10%, what is the estimated biomass at trophic level 4?

Answer: 50 kg

Question 2: A fishing boat catches 200 kg of fish from a trophic level 2 population per month. If sustainable fishing guidelines recommend harvesting no more than 15% of the biomass, what is the maximum allowable catch per month?

Answer: 30 kg

Question 1: Describe a simple experimental setup to assess the fish population in a local water body.

Answer: A suitable experiment involves selecting multiple sampling sites, using nets or traps to catch fish, recording the number and species caught, and calculating average fish density per area. Variables include time of day, water conditions, and net size. Safety precautions include wearing protective gear and handling equipment carefully.

Question 2: Identify two safety precautions that should be followed during fish sampling activities.

Answer: Wearing protective gloves and ensuring proper handling of fishing equipment to prevent injuries.

Question 1: A survey reveals that in a protected marine area, the biomass of fish at trophic level 2 is 1000 kg, while at level 3 it is 100 kg. What does this data suggest about energy transfer efficiency and fishing sustainability in this area?

Answer: The large decrease from level 2 to 3 indicates a typical energy transfer efficiency (~10%). It suggests that sustainable fishing at level 3 is possible if harvest levels do not exceed natural biomass decline, maintaining ecological balance.

Question 1: Discuss how sustainable fishing practices can help preserve trophic level balance and prevent ecosystem collapse. Include examples of methods used.

Answer: Sustainable fishing practices limit catch sizes, protect breeding stocks, and implement quotas to prevent overharvesting at key trophic levels. Methods include size limits, seasonal restrictions, and marine protected areas. These measures help maintain predator-prey relationships and overall ecosystem health, preventing collapse.

Question 1: Explain how the concept of trophic levels is used in designing sustainable fishing policies and quotas. Provide an example involving a specific fish species.

Answer: Trophic levels help determine the reproductive capacity and biomass of fish populations, guiding quotas to prevent overfishing. For example, in managing cod stocks, authorities set catch limits based on the fish's position in the food chain to ensure their populations remain stable and ecosystems stay balanced.