Ecological Impact of Fisheries

• per capita consumption: divide total consumption by total population size. Represents average individual consumption.

• How many factors can you think of the ecological impacts of fisheries? Why is it important to consider various ecologically important fisheries when we’re here to discuss marine wildlife conservation?

  • boat strikes, overharvesting, invasive species, ecotourism, non game birds affected by depletion of fish resources, composition of ecosystem,

• Methods to catch targeted fish species:

  • recreational/sport

  • artisanal

    • commercial

    • subsistence

  • traditional

  • industrial

• Common Fishing Gear

  • prawn trap

  • dive

  • groundfish bottom longline

  • shrimp beam trawl

  • groundfish otter trawl

  • purse seine

  • button trawling

  • deep sea dredging

• Fish

  • bluefin tuna

  • largest tuna: Atlantic bluefin, 1974, 1496 lbs

• Sharks and Finning

  • scalloped hammerhead shark

  • oceanic whitetip shark

• Non-targeted species mortality

  • catch of ocean wildlife and non-target fish

    • sea turtles

    • pelagic birds

    • sharks

    • marine mammals

    • coral

• Pelagic birds

  • albatross

    • mates for life, largest wingspan, sensitive to bycatch

Bottom Trawling

• NASA’s landsat satellite captured images of dozens of mudtrails (re-suspended sediment) dredged up by bottom trawlers

• impacts on coral

  • coral reefs and other hard bottom areas are flattened by bottom trawling

  • 23,000 square miles of rare deep sea corals and sponges from FL to NC and 13,000 sq miles from WA to Ca are protected by bans (enacted in 2010 and 2020, respectively)

• dredging for scallops

• 70% of benthic fauna found within 5-8 cm of sediment surface

Interruption of ecological succession

• whale fall

  • scavenger phase (eat flesh), opportunistic phase (worms and larval critters feed on other stuff), sulphophilic (release sulfur compounds)

  • can take years to complete!

• trawling can interrupt this process

Ecological impact of fisheries

• non-targeted mortality

• over harvest of targeted species

• habitat destruction

• change in abundance and biomass (Fishery and non-fishery species)

• reduction in distribution)

• decline in diversity

• change in community structure

Ecological context: community structure

• before and after disturbance:

  • species richness: total number of different species

    • decreases

Change in Biomass & Reduction of Distribution

• fishing has become an evolutionary selection agent

• organisms reproduce sooner but smaller size, impact fisheries

  • profit less for size of catch

Conservation Challenges

• how to manage for maintenance of biodiversity and human livelihood?

• how to manage for long lived fished and non fished species that migrate long distances and breed at predictable times and locations

• how to harmonize management across political territories?

• what else?

  • solutions: agreements between nations, funding,

Sustainable fisheries

• allowable catch that still makes money without harming populations

• TAC (total allowable catch)

• landing feeds, payments per tonne of landed fish

• Individual (tradeable) quotes

• technical modifications to target catch

UN Convention on the Law of the Sea (UNCLOS)

• Coast/Baseline → Territorial Sea (12nm) → Contiguous zone (limited law enforcement zone) 24nm → exclusive economic zone EEZ (200 nm → Extended Continental Shelf (max of 350 nm) → High seas (beyond 200 nm) Areas where no single nation has jurisdiction, requiring international cooperation for sustainable management of fish stocks.

• NM= nautical mile, 1.15 miles

• Endangered species monitoring is crucial to ensure that fishing practices do not further threaten vulnerable populations, and it involves tracking their populations and habitats to inform management decisions.

Fisheries Management (US)

• 8 regional councils are charged with developing conservation and management measures for marine fisheries in collaboration with the federal government

• East Coast

  • New England Fishery Management Council

  • Mid-Atlantic Fishery Management

  • South Atlantic Fishery Management

  • Atlantic States Marine Fisheries Committee

• WRC and NC Division of Marine Fisheries cover all of marine stuff

• NOAA is federal marine

Management Process Covers Diverse Fisheries

• 530 stocks (ranging from Arctic to tropical regions)

• 46 fishery management plans (using different strategies)

• Which stakeholders do we need at meetings for counting marine mammals?

  • people who are fishing, are knowledgeable in the situation

State Jurisdiction (3NM)

• State regulations govern

  • amount of fish to be taken

  • legal size limits

  • seasons (harvest/closure)

  • manner in which fish are taken)