Ecological Sampling

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Ecological Sampling
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Why Do We Sample?

• Determine presence and/or abundance
• Monitor population fluctuations
• Assess ecological damage
• Assess quality of habitat
• Assess population responses

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What Do We Sample?

• Physical Environment
• Temperature, DO, pH, salinity, clarity, flow,
  sediment
• Biotic Environment
• All living things

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Physical Habitat

• Temperature
• Mercury thermometer
• Electronic thermometer
• Long-term thermometers
• Dissolved Oxygen
• Winkler method (titration)
• DO meter (electrode)
• pH
• Litmus paper
• pH meter (electrode)
• Salinity
• Salinity Meter

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Water Clarity

• Secchi Disk
• Disk is attached to a calibrated rope. The disk
  is lowered into the water until the white parts
  can no longer be seen. Secchi disk depth is then
  recorded and serves as the waters transparency
  index. The clearer the water, the greater the
  secchi disk depth.

Secchi Disk
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Current Velocity (flow)

• Floating-orange method.
• Put an orange (or something else that floats just
  below the water surface) and measure the time it
  takes it to float across a known distance.
• Odometer-type flow meter
• Number of revolutions the propeller makes for a
  given time is calibrated to flow velocity.

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Sediment

• Sediment size is important to many aquatic
  organisms.
• Sieves are used to separate and grade sediment
  samples.
• Percent of each size grade can be determined

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Water Sample

• Water and plankton from various depths can be
  collected.
• A trigger mechanism is used to close the sampler.
• Sample is then brought back to the surface

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Small Mammals

• Mouse/rat Traps
• Fatal
• Pit Falls
• Bucket is placed in the ground
• Sometimes have leads to the buckets
• Live traps
• Havahart
• Sherman
• Spot-light

Sherman trap
Havahart trap
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Birds

• Stick-under-the-box method
• Bird-trap
• Works like a minnow trap
• Mist net
• Captures birds in flight
• Rocket net
• Uses a propellant to throw a net over birds

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Terrestrial Insects

• Sticky paper
• flies
• Baited Traps
• Fire ants
• Nets
• butterflies
• Foggers
• Collect insects from tree canopies

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Aquatic Insects

• Drift Net
• Place net in flowing water
• Kick Net
• Kick sediment upstream from block net and the
  flow will wash them into the net
• Wash bucket
• Serber or Hess Sampler
• Stir up known area of sediment
• Animals are collected by a catch net
• Multi-plate Sampler
• Become colonized

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Crawfish and Crab Traps
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Fish Larvae

• Light Traps
• Larvae are attracted to the light
• Ichthyoplankton nets
• Can be towed at various depths
• Fish collect at the codend

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Fish

• Lift net
• Net is placed down, and after a set amount of
  time it is quickly lifted
• Pop-net
• Similar to a lift net, but floats are attached to
  a framed net.
• Operated by a trigger mechanism
• Throw net
• A net attached to a heavy frame is thrown and
  every thing inside is netted out

Pop-net
Lift net
Throw net
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Minnow trap

• Usually use bait to attract small fish
• Light is used sometimes as an attractant

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Fish

• Electrofishing
• Electricity is put into the water
• Fish are temporarily stunned and usually swim
  towards the electricity source
• Usually non-fatal but may cause some damage

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Fish

• Gill Net
• Gill nets resemble tennis nets
• Fish can not swim completely through the net and
  get caught
• Gill nets are size selective (based on mesh size)

Square Mesh
Stretch mesh
Bar mesh
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Fish

• Trammel Net
• Three panels two large mesh on the outside and a
  small mesh on the inside
• Fish swim through the outer mesh, pushes the
  small mesh through the other side and becomes
  entangeled

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Hoop nets (and other similar nets) can have bait
or not. Fyke nets have leads to help guide fish
to the net.
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Seine

• Seines are nets that are pulled through shallow
  water to catch fish.

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Purse Seine

• Used to encircle entire schools of fish
• Usually involves a spotter plane and a second boat

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Trotline (longline)

• A series of baited drop lines connected to a main
  line.

Can be deployed by tying one end to the bank and
tying the other end with a heavy weight.
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Shrimp (or fish) Trawl

• Net pulled behind a boat along the bottom
• Either a beam or otter boards keep the net open

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Tagging Individuals

• Coded Wire Tags
• Microwire that has a unique label
• Magnetic wand detects the tag
• Tag retention should be determined
• T-Bar tags
• Can be individually numbered
• External tag
• PIT tags (Passive Integrated Transponders)
• Wand induces the tag to transmit, individual
  number is displayed

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Other Tagging Methods

• Toe clip
• Amphibian and reptile
• Clip of one or more toes to identify individuals
• Bird Band
• Place a metal band on a bird leg
• Generally has identification information