Lake Zonation

1
Lake Zonation

• Littoral Zone
• Deep water zone

• Open water zone
• Benthic Zone

2
Reservoirs

• Hydroelectric
• water flow
• nutrients
• horizontal stratification
• below-dam community
• Water supply
• No vegetative zone
• why?

Table Rock Lake
Truman Lake
3
Stream Zonation

• cold- warm-water
• e.g., Meramec River
• Cold-water fauna
• trout, smallmouth bass, cyprinforms, sculpins
• Cool-water fauna
• lmth smth bass, catfishes, walleye,
  cypriniforms
• Warm-water fauna
• largemouth bass, catfishes, gar, cypriniforms,
  shad, eels

4
Meramec River
Read Schlosser 1987 to understand why communties
change along a stream gradient.
5
Tropical Streams

• Is community assembly regulated more by
• Environmental factors?
• Biological Interactions?
• WHY?

6
Lake Malawi, Africa

• Rift lake ca. 2-5 MYA
• 560 km long
• 75 km wide
• 700 km deep
• Five broad habitats
• shallow bays and lagoons
• inshore mud / sand bottom
• inshore rocky
• open water
• deep water
• Each habitat has distinct cichlid species flock

7
Lake Malawi Cichlids

• gt 500 species
• Diversity stems from resource partitioning
• herbivores
• planktivores
• piscivores
• other carnivores
• Feed on other cichlids but not as predator
• scale eaters, fin nippers, egg eaters
• use mimicry to get close

8
Estuaries
Estuaries are the interface between the rivers
and the ocean.
9
Estuaries

• Harsh, fluctuating environment
• Rich in nutrients
• Diversity of fishes
• freshwater
• diadromous
• estuarine
• marine (dependent and nondependent)

10
Estuaries important nursery ground for many
offshore commercial fisheries
11
salt marsh
sea grass beds
mangroves