Post on 20-Jan-2016
Ecological Sampling
Why Do We Sample?
• Determine presence and/or abundance
• Monitor population fluctuations
• Assess ‘ecological damage’
• Assess quality of habitat
• Assess population responses
What Do We Sample?
• Physical Environment– Temperature, DO, pH, salinity, clarity, flow,
sediment
• Biotic Environment– All living things
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
YSI 550A DO Meter w/12' cable
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
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.
Sediment
• Sediment size is important to many aquatic organisms.
• Sieve’s are used to separate and grade sediment samples.– Percent of each size grade can be determined
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
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 trapHavahart trap
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
Terrestrial Insects
• Sticky paper– flies
• Baited Traps– Fire ants
• Nets– butterflies
• Foggers– Collect insects from tree canopies
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
Crawfish and Crab Traps
Fish Larvae• Light Traps– Larvae are attracted to the light
• Ichthyoplankton nets– Can be towed at various depths– Fish collect at the ‘cod’end
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
Throw net
Pop-net
Lift net
Minnow trap
• Usually use bait to attract small fish– Light is used sometimes as an attractant
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
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
Bar mesh
Stretch mesh
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
Hoop nets (and other similar nets) can have bait or not.
Fyke nets have leads to help guide fish to the net.
Seine• Seines are nets that are pulled through
shallow water to catch fish.
Purse Seine• Used to encircle entire schools of fish– Usually involves a spotter plane and a second
boat
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.
Shrimp (or fish) Trawl
• Net pulled behind a boat along the bottom– Either a beam or otter
boards keep the net open
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
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