I am completing standing‐stock surveys, and at multiple surveys I have been encountering the same item. Should I tally this item at each survey (assuming it is in one of the random transects)?

Yes! This is part of the reason that standing-stock surveys are informative. They provide information on the density of debris on the shoreline and how it changes over time. Debris that remains on the shoreline for long periods of time is part of the “standing-stock”. The persistence of the item should be noted in the notes section of the data sheet.