ACOUSTICS UNPACKED

A General Guide for Deriving Abundance Estimates from Hydroacoustic Data

 

 

 

 

Time budget

Generating a time budget is a necessary step in the survey design process (Table 4).  With a detailed budget, you can quickly determine whether additional time is needed to meet survey objectives or whether achieving multiple objectives is not feasible with available time.  Necessary considerations or inputs include:

  • amount of total time available (if fixed), including any diel considerations
  • logistic constraints associated with docking, accommodations, etc.
  • optimal vessel speed during acoustic survey and transit
  • time required for individual tasks (e.g., trawling, stationary sounding)
  • Table 4.  An example time budget showing possible categories and calculations.

    Day

    Activity

    #

    Dist (nmi)

    Speed (knot)

    Time (hr)

    Total time (hr)

    Day hours

    1

    Transit to start

    1

    10

    10

     

    1.0

     

     

    Systematic

    4

    10

    6.5

     

    6.2

     

     

    Trawling

    2

     

     

    1.0

    2.0

     

     

    Adaptive

    2

    2

    6.5

     

    0.6

     

     

    Stationary

    1

     

     

    1.0

    1.0

     

     

    Transit to dock

    1

    15

    10

     

    1.5

    12.3

    2

    Transit to start

    1

    15

    10

     

    1.5

     

     

    Systematic

    4

    10

    6.5

     

    6.2

     

     

    Trawling

    2

     

     

    1.0

    2.0

     

     

    Adaptive

    2

    2

    6.5

     

    0.6

     

     

    Stationary

    1

     

     

    1.0

    1.0

     

     

    Transit to dock

    1

    20

    10

     

    2.0

    13.3

     

     

     

     

     

     

     

     

     

    Total transit

    4

    60

     

     

    6.0

     

     

    Total systematic

    8

    80

     

     

    12.4

     

     

    Total trawling

    4

     

     

    4.0

    4.0

     

     

    Total adaptive

    4

    8

     

     

    1.2

     

     

    Total stationary

    2

     

     

    2.0

    2.0