Midterm #2

• Biocomplexity: biological systems have emergent properties that exceed the sum of their elements, displaying resilience and adaptation.
• Sockeye salmon in Alaska display biocomplexity through self-organizing populations with emergent behavior of sustainability.
• Biocomplexity has enabled sockeye salmon populations to sustain fisheries production despite climactic changes.
• Biodiversity: diversity of life forms.
• There exists a diversity of life history and morphology within species.
• Diversity of life history is the key to the biocomplexity of sockeye salmon populations.
• Salmon in Alaska have adapted with different times of juvenile and adult migrations.
• The local population integrity of a species is maintained by the behavior of adults.
• A species local population integrity may result in reproductive isolation, causing the fish to develop phenotype characteristics exclusive to their population.
• Extirpation: the complete removal of a species from a habitat.
• Lack of awareness of a slow-growing species within a fisheries stock area may result in extirpation by overfishing.
• In Atlantic Canada, redfish stock include: Acadian redfish (fast growing) and Deepwater redfish (slow growing).
• Species: a group of similar individual organisms capable of reproducing with one another to produce fertile offspring.
• Fish stock: a management unit defined for operational purposes.
• All organisms within a stock area are assumed by fisheries managers to have the same value for the biological production parameters.
• Fish population: a group of individuals of one fish species that live in a particular geographic area and freely interbreed.
• Ideally:

  • A stock is a single population of fish
  • The stock area contains as much of the fish population as possible
• In practice, a stock may include only part of a population.
• In the past, boundaries of stocks were based on productivity parameters.
• A goal of modern management is to maintain the genetic diversity of populations.
• Size selective fishing:

  • Removes the largest individuals from a population
  • Changes the size distribution of the population
  • Removes the biggest breeders
• Fisheries induces evolutionary pressure for individuals to spawn sooner at a smaller size.
• Ecological memory: past environmental conditions and subsequent selection on populations are encoded into the current structure of biological communities and are reflected in the genetics of species.
• Past experience determines the present genetic makeup.
• The future state or evolution of a biological system depends on its past experience.
• Coral reefs exhibit ecological memory and resilience to rising sea temperatures.
• As biological systems are open systems with many possible futures, scientists are unable to predict the future of biological systems.
• Biological systems have many possible futures due to cell genetic mutation and epigenetic mechanisms in the adaptation of species.
• There are fundamental limits to the predictability of biological systems as it would require a complete knowledge of the past and present.
• It is not necessary to be able to predict biological systems to form theories.
• Epigenetics: the environment "turning on/off" sections of DNA to adapt .
• Biocomplexity allows for resilience and adaptability.
• Fish species grow slower in colder waters.
• The effects of bottom trawling on an ecosystem depend on the sea bottom of the area being trawled.
• Hard bottom habitats and invertebrate communities are damaged by bottom trawling.
• Cod aggregate offshore in the winter to spawn.
• Flat sea bottoms are repeatedly dredged for scallops.
• A Marine Protected Area (MPA) has its own management plan developed by the local resource users and Fisheries and Oceans Canada.
• Marine Stewardship Council (MSC): and ENGO which sets a standard for sustainable commercial fishing.
• Fishing industries that wish to be advertised as sustainable are assessed by a team of independent experts.