Question 1: Define sustainable fishing and explain its importance in managing trophic levels in an ecosystem.

Answer: Sustainable fishing involves harvesting fish at a rate that allows populations to replenish naturally, ensuring long-term availability. It is important for maintaining ecological balance, preventing overfishing, and conserving biodiversity within trophic levels.

Question 2: Describe how overfishing of top predators can affect the entire trophic pyramid.

Answer: Overfishing top predators reduces their population, which can lead to an increase in prey species, disrupting the balance of the ecosystem and potentially causing overpopulation of lower trophic levels, which may result in habitat degradation.

Question 1: A fish population has an initial biomass of 500 kg. If sustainable fishing practices allow harvesting 10% of the biomass annually, how much biomass can be harvested in one year? Show your calculation.

Answer: Biomass harvested = 10% of 500 kg = 0.10 × 500 kg = 50 kg.

Question 2: If a predator at the top of the food chain consumes 1000 kg of prey, and the energy transfer efficiency between prey and predator is 10%, how much energy (in kg) was originally present in the prey at the lower trophic level? Use the formula: Energy at top level = Energy at lower level × efficiency.

Answer: Energy at lower level = 1000 kg / 0.10 = 10,000 kg.

Question 1: Design a simple experimental outline to test the effectiveness of a new sustainable fishing quota policy. Include the variables you would measure and safety precautions.

Answer: The experiment would involve implementing the quota policy in a specific area and monitoring fish populations over time. Variables include fish biomass, species diversity, and reproductive rates. Control areas without quotas would be used for comparison. Safety precautions include ensuring proper boat handling, wearing life jackets, and avoiding overexertion or hazardous weather conditions.

Question 1: A report states that after implementing sustainable fishing measures, the biomass of cod increased from 200 tonnes to 350 tonnes over five years. Explain what this suggests about the effectiveness of the measures and the possible impacts on trophic levels.

Answer: The increase in cod biomass indicates that the sustainable fishing measures were effective, allowing the population to recover. This can help restore balance in the trophic pyramid, potentially leading to healthier ecosystems and improved fish stocks for future fishing.

Question 2: Discuss how technological advances in fishing gear can contribute to sustainability, and mention potential risks if not managed properly.

Answer: Technological advances, such as selective fishing gear and GPS tracking, can reduce bycatch and prevent overfishing by targeting specific species and areas. However, if not properly regulated, these technologies may lead to overexploitation, habitat damage, or unintended harm to non-target species, undermining sustainability efforts.