Serrated wrack or Toothed wrack is a common wrack seaweed that grows just above the low water mark on rocky shores. Its name comes from the serrated edges on its fronds. These edges are so serrated that some people even call this seaweed Saw Wrack. Serrated Wrack provides shelter for many creatures in the lower shores, including Flat periwinkles and many small crustaceans. Other seaweeds are found to grow on its fronds, including Dulse. The dense bunches provide shade and shelter in rockpools too - lift up a bunch and see what's hiding underneath (though make sure you put everything back where you found it!).
What to look for
An olive-brown brown 'wrack' seaweed, recognised by the strap-like branching fronds with jagged serrated edges.It does not have air bladders and the fronds are flat not spiraled.
Where to find
Common on rocky shores all around our coasts.
Did you know?
Reproduction in Serrated wrack peaks in late summer when gametes are released into the water to be fertilised externally. Female Serrated wracks can release more than a million eggs. These eggs produce a pheromone called Fucoserratin that acts as a sperm attractant!