The document discusses various types of orientation and movement behaviors in animals, including taxis responses like phototaxis, geotaxis, chemotaxis, and thigmotaxis. It then focuses on migration, defining it as directed mass movements between places on a regular basis. The document discusses reasons for migration like following food and breeding habitats. It also mentions costs of migration like energy expenditure and increased predation risk. Methods for studying fish migration are discussed, including acoustic telemetry using tags that emit unique signals and receiver arrays to track fish movements over long periods of time.
4. Why migrate? (what are the benefits?)
Where/when does it occur?
What are the negative consequences of migration?
So, why migrate anyway?
Explain anadromy vs. catadromy
5. “(migration) occurs when the gain in fitness from
using a second habitat minus the migration costs of
moving between habitats exceeds the fitness from
staying in only one habitat.”
(Gross 1987)
6. Why migrate?
Habitats for different life history periods vary
But, there are liabilities:
energetic costs
drifting (getting lost, or displaced by currents)
exposure to predation
Migration
7. I. Function
feeding (daily)
follow food abundance
breeding (seasonal)
place offspring in their ideal habitat
minimize potential for cannibalism
wintering (seasonal)
adjustment to temperature
Migration may be horizontal OR vertical
Migration
8. II. Timing
daily (usually feeding)
seasonal/annual (wintering and reproduction)
lifetime - ontogenetic (e.g. salmon, lamprey)
Migration
adult feeding area
nursery area spawning area
9. III. Environment
diadromy: ocean fresh
anadromy ocean fresh (to breed)
catadromy fresh ocean (to breed)
obligate (eel)
facultative (sculpin)
amphidromy fresh ocean or ocean fresh
…but not for breeding (life cycle)
potamodromy fresh fresh
oceanodromy ocean ocean
Migration
10. “The contrasting directions of migration can largely be
explained by the relative availability of food resources in ocean
and freshwater habitats." Gross et al. (1988)
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relative level geographic predominating
of productivity location migratory mode
oceans > freshwaters temperate anadromy
latitudes
freshwaters > oceans tropical catadromy
latitudes
Migration