Untitled Flashcards Set

Migrations

• Types of migratory patterns:

  • Anadromous (e.g., salmon) – fish migrate from saltwater to freshwater to spawn.

  • Catadromous (e.g., eels) – fish migrate from freshwater to saltwater to spawn.

  • Oceanodromous – migration occurs entirely within saltwater.

  • Potamodromous – migration occurs entirely within freshwater.

• Cues for migration:

  • Temperature changes, daylight length, and food availability.

  • Chemical cues (e.g., scent of natal rivers in salmon).

  • Lunar and tidal cycles influence movement.

• Problems managing migratory stocks:

  • Overfishing during migration.

  • Habitat destruction (e.g., dams block migration).

  • Climate change altering migration patterns.

• Vertical migration:

  • Organisms move up and down the water column daily.

• Diel migration:

  • A type of vertical migration where marine organisms (e.g., zooplankton) move to surface waters at night to feed and descend to deeper waters during the day for protection.

Dams and Fisheries

• Why do we build dams?

  • Hydroelectric power, flood control, water storage, irrigation.

• Dams physically block movement upstream and downstream

  • Fish cannot reach spawning grounds.

  • Interrupts natural water flow, affecting sediment transport.

• What life stages are affected the most?

  • Spawning adults and migrating juveniles.

• What do we do to make it easier for fish to go around or through the dam?

  • Fish ladders, bypass channels, and trap-and-haul systems.

• What is a trophic upsurge in a reservoir?

  • A temporary increase in productivity after dam construction due to increased nutrient availability.

Aquaculture

• Top countries involved:

  • China, India, Indonesia, Vietnam, and Bangladesh are leading in aquaculture production.

• Top products involved:

  • Shrimp, tilapia, salmon, catfish, oysters, and seaweed.

• Applications of aquaculture—what is important in Florida?

  • Florida focuses on shrimp farming, shellfish (oysters and clams), and ornamental fish production.

• How important is seafood in world fish production now and in the future?

  • Currently, about 49% of world fish production comes from aquaculture, and this percentage is expected to grow due to declining wild fish stocks.

Estuaries

• What physical features change or stay stable throughout the year?

  • Salinity, temperature, and nutrient levels fluctuate with tides and seasons.

  • Sediment composition and depth remain relatively stable.

• Ranking habitats based on primary productivity:

  • Highest: Salt marshes → Seagrass beds → Mangroves → Open water.

• Features of salt marshes, mangroves, and seagrass beds:

  • Salt marshes: Highly productive, provide habitat for juvenile fish, protect shorelines from erosion.

  • Mangroves: Act as nurseries for many fish species, reduce coastal erosion.

  • Seagrass beds: Stabilize sediments, improve water quality, provide food and shelter for marine life.

• Food webs of estuarine habitats: indirect or direct? What does that mean?

  • Mostly indirect – detritus-based food webs where decomposing organic material supports the ecosystem.

• Why are estuaries important to fisheries?

  • Serve as nurseries for many commercially important fish and shellfish species.

• What human-induced impacts have estuarine habitats faced in the past (and continue to face)?

  • Pollution, habitat destruction, climate change, invasive species.

• Life cycle of a typical estuarine fish (Red Drum example):

  • Spawning in offshore waters → Larvae drift into estuaries → Juveniles grow in seagrass beds/marshes → Adults migrate offshore to spawn.

  • This is a guaranteed exam question!

Warmwater and Coldwater Coral Reefs

• Compare and contrast reef types:

• What human-induced impacts do tropical coral reefs face?

  • Coral bleaching (caused by rising sea temperatures).

  • Ocean acidification (weakened coral skeletons).

  • Overfishing and destructive fishing practices.

  • Coastal development leading to habitat destruction.

  • Pollution (nutrient runoff causing algal overgrowth).