mudflat temp

Alarm bells are ringing for plants, algae and sea creatures stressed by the current heatwave in  mudflats, shallow mudlat pools and coastal rocks where temperatures have exceeded 30C. 

“While there isn’t much we can do to help sea life, we have advice on how to avoid exasperating the situation, and we are asking people to record what is happening,” says Karin Dubsky, Coastwatch European International Coordinator.

Coastwatch is gathering information on areas and species: which are more resilient; is mass death occuring and if so what is the cause; are fish and other mobile inshore sealife moving into seaweed forests for cover?

What damage is this heat doing to juvenile fish (eel, lamprey, flounder) which tend to stay in the stream mouths that are now drying out?

Advice and requests

  • avoid walking over seagrass and other sensitive habitats to minimise stress
  • suspend bait digging during heatwave
  • don’t pick seafood now and warn others this is not a time to eat wild seafood. Poisonous plankton species have been recorded by the Marine Institute
  • Botulism is possible in seagulls from digesting Clostridium bacteria which produces a potent poison and can be transferred to humans. Watch for signs of ‘drunk’ or dying seagulls and report to your local authority. Keep children and dogs away


Mud and sandflats

Overheating and lack of oxygen with recorded intertidal mud temperatures above 30C in Dublin Bay. Temperatures were highest in the mid to upper shore in darker mud areas and the shallow sandy mud pools where dislodged decaying green seaweeds would have added to the problem by using oxygen during breakdown. Conditions are also perfect for botulism.

Stress intertidal seagrass (Zostera species): Merrion Strand, Co Dublin and Salthill, Co Galway

Blackened grass blades in overheating mudflats and die back. (This protected habitat grass is favoured by Brent geese for its high calorie food in Autumn)

Seashells and cockles that normally live in the sediment are rising to the surface and mud snails normally visible on mud have disappeared

Rocky shores

Rich barnacle settlements on rocks observed in early June have been wiped out except on north facing surfaces and overhangs and the typical green seaweed fringe on intertidal rocks near fresh water inflows has turned white.

Pink Coralina seaweed fronds that form a busy calcerous band in many pools are bleached white and are dropping.

Contact Coastwatch or Karin Dubsky on 086 8111 684