The do-nots

Do not enter the water, flooded banks, drains, manholes, culverts or private land, and never open or interfere with an outfall or drain. No photo is worth an injury — everything you record, you record from a safe public or club access point.

Do not name a person, farm or business as the cause — not online, not in the group chat, not on the bank. Even a well-meant accusation can damage a future prosecution and expose you to legal risk. Record facts; the authorities work out the cause. General photos of the affected water are fine and useful — photos framed to blame a specific premises are not.

• Don't take water samples — done wrong they have no evidential value, and collecting them can be dangerous. Official samples are taken by officers to a legal standard.
• Don't move or collect dead fish unless an officer asks you to. Investigators need to see where the mortalities are and how many; if disease is suspected, the Marine Institute may need fish fresh.
• Note where the dead fish are and roughly how many — a few, dozens, hundreds — and how long a stretch is affected.