Frequently Asked Questions

Here are answers to our most frequently asked questions. Not finding your question here? Feel free to email or call the COASST office.


What is pacing used to measure?

Pacing is a unit COASST uses for measuring two things:

  1. Determining and getting to sampling rectangle locations if you are surveying for medium and small marine debris (only marine debris surveyors do this).

  2. Measuring zone widths (both beached bird and marine debris surveyors do this).

Won’t pacing result in "sloppy" data?

Yes.  Substrate type, solidity/looseness, uphill/downhill steepness, weather, and other favors can affect the accuracy of the paces per meter (paces/m) measurement, which COASST uses to convert zone widths from paces back into meters.

COASST is all about appropriate precision.  For instance, identification of a bird to species is dependent on the measurements of the wing, bill and tarsus that are accurate and precise to the centimeter (or less!).
Much larger distances, like beach zone widths, or lengths down the beach where marine debris rectangles are located, can sustain a coarser unit of measurement.  Neither of these purposes require sub-meter, or even meter accuracy.

For marine debris sampling locations, pacing is a simple way to get from one location to the next.  The important points are to have these locations randomly selected each survey and distant enough from each other so that there is no interference.

For beach zone widths, pacing is a simple way to get a general indication of the relative size of each zone.  That is, what proportion of the total beach width each zone comprises.


What is the purpose behind measuring beach zones?

Knowing the approximate width of a beach, and of the zones comprising that total width, allows COASST to create a more accurate estimate (statistical model) of the true density (carcasses or debris objects per unit area) of things. 

The presence and width of beach zones can indicate two important things:

  1. The likelihood of detection: wood and wrack zones can "hide" the presence of carcasses or debris.

  2. Accumulation: birds, debris and other flotsam are deposited and “stick” to each beach zone differently. In particular, wrack accumulates small things (like plastic fragments).

How do I record beach zones that are missing or that I didn’t survey?

It is important for COASST to know the difference between no data (that is, no measurements were made), absence of one or more zones, and a zone was present but not surveyed due to extenuating circumstances like safety concerns.  Here is how COASST would like you to distinguish:

  1. If a zone is not present (e.g., there is no wrack, or no wood at the location you are measuring the zone widths), record a “0” (literally, a zone width of zero) on your datasheet.

  2. If a zone is present but not surveyed for safety reasons (e.g., a wood zone of large slippery logs or a surf zone of mudflats), put a “UM” (stands for unmeasured) on your datasheet.

  3. If a zone is present and you choose to estimate its width rather than actually pace it (e.g., same scenario as above), write a comment indicating you estimated instead of actually paced.

What if the zones on my beach overlap?

If multiple zones appear to be present in equal levels, follow the following hierarchy:

  • When wrack and surf are present, call it wrack.
  • When wood and wrack are present, call it wood.
  • If vegetation and any other zone are present together, call that zone vegetation.

Like most other things in COASST, think in terms of predominance. The vegetation zone begins when vegetation becomes a consistent on the section of beach that you are measuring. A few sparse plants don't count. An odd log or two does not constitute a wood "zone", but an area where many logs have accumulated does.

What do I do with wood in the wrack zone?

Wrack is (almost) all of the floating material deposited by the tide.  Obviously most of the wood on a beach came in on the tide at some point, usually during storms where big waves have “thrown” the wood high up on the beach, which would include material that makes up the wood zone. 

Think of the wrack as the material that has been deposited on successive days of the tidal cycle.  It is all of the small stuff (i.e. seaweed, shells, Velella velella, and small/medium marine debris) that could easily be washed away and re-deposited in the next days of the tide washing in and out.

Wrack may include some wood pieces, but it is less likely that a continuous line of large logs washes in and out daily on the tide. That more permanent line of wood would be defined as the wood zone.


I know I’m supposed to measure zone widths at the start and turnaround points on my beach, but these locations are very different (not typical) of the beach.

The COASST protocol has instructions for measuring zone widths on a simplified beach (knowing that all COASST beaches are different, and may be quite different from the version in the protocol).  Using the start and turnaround points as places of measurement are suggested because these are known locations that are convenient, and at which you are literally walking the width of the beach anyway. 

If these locations are not convenient, or are not "typical" of your beach (i.e. the start and turnaround points are actually roadways where vehicles enter the beach), don't use them!  Instead, select two locations that are typical and that are convenient to how your team surveys the beach. 

Here are some general guidelines:

  1. Choose two locations along your beach that you feel are “typical” of the beach on that day.

  2. Make sure they are not right next to each other—they should be at least 50 paces apart from one another.

  3. If it is easier to establish these as set locations (same place every time), then do that.  On the other hand, if the beach is tremendously variable across time so that you feel that choosing locations each time is better, then do that.

  4. Don’t worry about the absence of zones, the beach is what it is.  For example, if a storm deposits wrack from the surf zone up into the vegetation, then you’ve got a darned wide wrack zone!  You can always annotate in the comments section on the COASST cover sheet.

  5. Know that the surf zone will always be the most variable in width, because of the tide.

I know I’m supposed to measure zone widths at the start and turnaround points on my beach, but I access from the middle.

That’s OK! What's most important is that:

  1. You select locations that are "typical" of your beach.

  2. You select locations that are easy (hence the guidelines to pace at the start and turnaround points, because you enter the beach from the back and can easily walk down towards the water, counting paces per zone as you go, and vice versa walking up the beach at the turnaround). If you access the beach from somewhere other than one of the ends, use the general guidelines listed above.