Open Access

The effects of raking irish moss(Chondrus crispus) on lobsters in Prince Edward Island

  • D. J. Scarratt1
Helgoländer wissenschaftliche Meeresuntersuchungen24:BF01609530


1. The number of damaged lobsters(Homarus americanus) seen aboard commercial moss raking boats varies with the abundance of lobsters on the grounds, but is low in comparison with the numbers known to be damaged.

2. Lobster abundance is highest on rough, boulder strewn moss beds, and lowest where beds are smooth.

3. Some lobsters are seen to escape from the path of the rake unharmed. The proportion avoiding the rake is lowest on rough grounds, and highest on smooth grounds.

4. Examination of rake tracks in heavily raked areas shows that up to 5.2 % of lobsters in the path may be killed by each passage of the rakes.

5. Up to 280 lobsters, average size 35 mm carapace length, average value 8 c each, may be killed by one moss raking boat in one day. More lose claws or are wounded.

6. Total value of lobsters killed by all rakers in one area is $ 36,000 which is 18 % of landed value of moss or 7 % of lobster landings.

7. Some control of moss raking is justified.