Notes on Fish, Fisheries, and Genetically Engineered Foods

Agenda

  • Overview of fish and fisheries
  • Discussion on genetically engineered foods

Fish

  • Atlantic Cod Overview
    • Known for its high reproductive capacity.
    • Cod lays between 3 to 9 million eggs per spawning event.
    • Quote from Mark Kurlansky highlights the disparity in how the cod, despite its high productivity, is often overlooked compared to less prolific species like the hen.

Cod - Basic Biology

  • Characteristics
    • Bottom-dwelling species.
    • Historically, cod could weigh more than 100 lbs, but current catches are mainly between 55-77 lbs.
    • Maximum age is over 20 years, but most caught today are 2-5 years old.
    • Reaches sexual maturity at 2-4 years old.
    • Historical references note 9,384,000 eggs in a mid-sized cod.

Range

  • Cod are spread across various important locations, including the Gulf of Maine, Bay of Fundy, and surrounding areas such as Portland, Bangor, and Saint John.

History

  • Native and Colonial Impact
    • Served as a critical food source for Native Americans and European settlers.
    • First successful industry in colonial America.
  • Fishing Evolution
    • By the early 1900s, bottom trawling became popular.
    • In the 1950s, larger ships with processing facilities started operations.
    • 1960s witnessed the removal of 60% of adult cod in US/Canada annually, leading to significant population declines.

Spawning Stock Biomass and Recruitment

  • Graphs and Data:
    • Spawning Stock Biomass fluctuated significantly from 1962 to 1992.
    • Recruitment of new juvenile cod aged 3 years also recorded variations, highlighting a trend of declining biomass.
    • Natural mortality assumed constant at 18% per annum.

Decline of the Newfoundland Cod

  • In 2003, the Newfoundland cod population was declared "endangered" by the Canadian government due to severe depletion.

Effects of Overfishing

  • Alters size and age distribution of fish populations.
  • Female cod spawn earlier than previous norms, reducing overall reproductive output:
    • Early spawning at 3 years vs the historical range of 5-6 years.
    • Younger females produce fewer and smaller eggs, impacting fry size.

Industrial Fishing Methods

  • Various techniques include:
    • Driftnets: Large nets that drift with current and catch by entangling.
    • Longline Fishing: Involves a long line with baited hooks.
    • Trawling: Dragging a net through the water.
    • Bycatch: Unintended catch of non-target species associated with these methods.

Bycatch and Conservation Efforts

  • For instance, in Australia, the prawn industry's bycatch ratio was found to be 8:1.
  • Turtle Excluding Devices (TEDs) have been shown to reduce bycatch of turtles significantly.

Fish Farms: Pros and Cons

  • Pros
    • Eliminate bycatch.
    • More efficient production.
    • Reduces fishing pressure on wild populations.
  • Cons
    • Waste generation.
    • Use of antibiotics and pesticides.
    • Introduction of non-native species can disrupt local ecosystems.

Wild-caught vs Farm-raised Fish: Concerns

  • Wild-caught: Issues include overfishing, bycatch, and ecosystem impacts from trawling.
  • Farm-raised: Concerns about chemical use, nutrient runoff, and escape of farmed fish into the wild.

Genetically Engineered Foods

  • Overview of GE Foods:
    • Common US GE foods include corn, soybeans, and now genetically engineered salmon.
  • Terminology
    • "Genetically Modified (GM)" vs. "Genetically Engineered (GE)”.
  • Adoption: A significant rise in planted acres of HT (herbicide-tolerant) soybeans and Bt (Bacillus thuringiensis) corn from 1996-2024.

Potential Uses for GE Plants

  • Enhancements in agriculture, potentially making medicines, and creating other useful products.
  • Benefits can include increased yields, higher nutrient content, and environmental sustainability through lower pesticide use.