Notes on Fish Population and Fishing Quotas

Overview of Fishing Dynamics

• Observations of fish stock indicate:
  • Catch levels falling or remaining constant despite increased fishing effort.
  • More boats, larger sizes, and advanced technology contribute to increased effort.
  • Declining catch suggests declining fish population.

Case Study: Grand Banks Cod

• Decline of cod population off the eastern coast of Canada.
• Scientists indicated overfishing, but policymakers ignored warnings due to high catches.
• Resulted in a ban on cod fishing for over 20 years due to low population.

Fish Population Modeling

Population Growth Dynamics

• Fish population growth follows a curve:
  • Initially low growth when population is low.
  • Growth accelerates as population increases, then slows as resources become limited.
  • Death rate equals birth rate at carrying capacity.
• Ecosystems are dynamic, affecting carrying capacity.

Key Points on Growth Rate vs. Population

• Growth rate is low at low populations and high populations.
• Optimal growth occurs at intermediate population levels.
• Sustainable practices must consider growth rates in relation to population.

Fishing Quotas and Economic Rent

Determining Sustainable Quotas

• Catches can be sustainable if kept below growth line.
  • Maximum Sustainable Yield (MSY) allows for maximum catches without harming population.
• Quotas should aim to maximize economic rent for fishermen rather than just sustainable yields.

Understanding Economic Rent

• Economic rent = profit (difference between revenue and costs).
• Goal is to maximize sustainable profits over time.

Revenue and Costs in Fishing

• As fishing effort increases, total revenue initially rises, but eventually plateaus.
• Costs will rise with increasing effort, affecting economic rent.
• Maximum Economic Yield (MEY) occurs at a point where the difference between revenue and costs is maximized.

Open Access Scenarios in Fisheries

• Multiple fishermen have different incentives:
  • Individual fishermen stop fishing at MEY, but multiple entrants can lead to overfishing.
• Open access leads to less rent being generated and potential collapse of fish populations.

Conclusion and Future Directions

• The goal is to structure fisheries to maintain fish populations while maximizing economic rent.
• Future discussions will explore challenges and strategies to achieve sustainable fishing practices.