Environmental Engineering Reference
In-Depth Information
Analysis type
Field application
Key advantages
Key disadvantages
Mark-recapture
Live recapture
Requires relatively low technical capacity
Usually labour-intensive; can disrupt
(con't)
behaviour and distribution of the population
Camera trapping
Eliminates the need for live trapping
Requires natural individual-specific markings
(stripes, spots etc.); high start-up costs
Genetic (hair, dung)
Eliminates the need for live trapping
Requires high technical capacity
Offtake-based
All
Data readily available when harvest
Often biased by heterogeneous capture
well-monitored, minimising effort required
probability or poor quality data; require heavy
depletion
Catch-effort
Can be developed into full population
Easily biased by inappropriate measurement
model if applied over longer periods
of effort
Change in ratios
Data requirements relatively modest
Population needs to be structured into readily
observed categories, with harvest strongly
skewed
Catch-at-age
Gives detailed age-structured results
Extremely data-demanding, not widely
applicable outside large-scale fisheries
Others
Indirect sign
Can be applied to otherwise invisible species
Great scope for bias in calibrating sign with
abundance
Presence-absence
Useful for species both rarely seen and hard
Sampled area usually difficult to define
to catch; flexible data requirements
 
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