Fisheries and Fishing Techniques

Fisheries Overview

  • Fisheries Definition: Systems established for the harvesting of fish populations.
  • Fishing Techniques: Various methods employed in fisheries, including nets, lines, traps, and modern industrial methods.

Overfishing

  • What is Overfishing?: The depletion of fish stocks due to excessive hunting beyond natural reproduction rates.
  • Causes:
    • Increased demand for seafood.
    • Advances in fishing technology.
    • Lack of effective management practices.

Marine Fishery Systems

  • Commonly found:
    • Near shallow coastal shelves.
    • In deeper, open waters.
  • Impacts on marine environments:
    • Altered Ecosystem Biodiversity: Disruption of food chains and habitat balance.
    • Altered Physical Traits of Habitats: Changes in seafloor topography and vegetation.

Historical Context of Fishing

  • Fishing History:
    • Humans have engaged in fishing for thousands of years.
    • Initially, only coastal fish species were at risk due to limited range and weather conditions.
    • Misconceptions about sustainability prevalent due to historical practices.

Case Study: Collapse of Cod Fisheries

  • Atlantic Cod: A historically significant fish for North American fisheries.
  • Long-standing targeting by fishermen leading to its near collapse.

Technological Impact on Fishing

Industrial Revolution Advances:
  • Key developments:
    • Steam trawlers and diesel engines.
    • Hydraulic winches and echosounders.
    • Inboard refrigeration.
    • Real-time oceanographic data.
  • Technology Consequences:
    • Increased capture efficiency and fishing volume.
Global Fisheries Catch Trends
  • Increasing global fisheries catch since the 1950s through aquaculture and wild capture.

Types of Fishing Techniques

  • Industrialized Fishing Methods:
    • Factory Fishing: Large vessels using advanced tech to maximize catch.
    • Driftnets: Unattached vertical nets that catch various fish species.
    • Longline Fishing: Long lines of baited hooks targeting specific fish such as tuna.
    • Trawling:
    • Midwater Trawling: Targets pelagic fish like tuna.
    • Bottom Trawling: Targets seabed fish like cod.
    • Purse Seining: Targeting large schools of fish using weighted nets.
    • Pots, Traps, and Creels: Various mechanical traps for capturing fish.

U.S. Commercial Fishery Methods Distribution

  • Purposive Distribution:
    • Purse Seine (25%), Trawl (54%), Pot and Trap (7%), Longline (5%), Gillnet (3%), others.

Environmental and Economic Issues

  • Overexploitation:
    • 30% of U.S. fish stocks are overfished; many with unclear status.
    • “Fishing down the food web” phenomenon observed.
  • Economic Impact:
    • Significant job losses and economic downturn due to declining fish populations in regions like the Northwest and North Atlantic.

Marine Reserves as a Solution

  • Goals of Marine Reserves:
    • Increase fish biomass and sizes, decrease mortality, and protect migratory species.
    • Enhance ecotourism opportunities.

Key Legislation: Magnuson-Stevens Act of 1976

  • Established 200-mile Exclusive Economic Zone (EEZ).
  • Created Regional Fishery Management Councils for sustainable management practices.

Exclusive Economic Zone (EEZ) Concept

  • Definition: Area extending 200 nautical miles from a country’s coast where it has exclusive rights for resource management.
  • Conflicts may arise (e.g., Cod Wars between the UK and Iceland).

Related Legislation: Marine Mammal Protection Act (MMPA)

  • Prohibits the capture and disturbance of marine mammals in U.S. waters and creates certain exemptions for native practices.

Exit Ticket Reflection Questions

  • Identifying Problems: What is wrong with the global fisheries situation?
  • Proposing Solutions: What are potential solutions to address the situation?
  • Personal Reflection: What aspect of the learning stood out to you?