Driftwood with holes made by Gribbles & Shipworms

Driftwood with infestation damage: Small piece of water-logged driftwood with holes made by Gribbles and Shipworms from the strandine at Rhossili Bay, Gower, South Wales (1) 

The photographs in this post show a small piece of water-logged driftwood about 30 cm long and riddled with holes and tunnels caused by two different types of wood-boring sea creatures. The larger borings are about 1 cm in diameter and many are lined with a smooth calcareous material that has become stained through burial in the beach sediments. These larger borings may be familiar to beachcombers as being made by Shipworms, Teredo navalis Linnaeus. I have talked about these worms – which are not really worms but bivalved molluscs – elsewhere in the blog.

Less familiar, are the much smaller holes and burrows in this piece of soft wood. These have been made by Gribbles, Limnoria lignorum (Rathke). Gribbles are very small marine isopod crustaceans. Crustacea is the major grouping  that includes the crabs, prawns, and sandhopper types of animal. Isopods are a bit like the terrestrial woodlice that you see in gardens – they have an ‘armoured’ body with lots of limbs and joints; and their body is flattened from top to bottom – compared with amphipods such as sandhoppers in which the body is flattened from side to side. Gribbles are very small and their length rarely exceeds 3.5mm.

Shipworms can burrow into hard wood but Gribbles prefer wet, cool and soft wood, like the bases of exposed pilings on piers and jetties. The pictures here show the infestation damage caused by both Gribbles and Shipworms that leads to the destruction and disintegration of the timber.

Gribble holes in driftwood: Detail of small holes and burrows made by marine isopod crustaceans called Gribbles, Limnoria lignorum (Rathke), in a piece of driftwood from the strandline at Rhossili Bay, Gower, South Wales (2) 

Driftwood with infestation damage: Close-up of hole and burrow infestation damage made by marine isopod crustaceans called Gribbles, Limnoria lignorum (Rathke), in a piece of driftwood from the strandline at Rhossili Bay, Gower, South Wales (3) 

Damage by Limnoria lignorum (Rathke): Damage caused by marine isopod crustaceans called Gribbles, Limnoria lignorum (Rathke), and Shipworm molluscs Teredo navalis Linnaeus, in a piece of driftwood from the strandline on Gower, South Wales (4) 

Comparison of Shipworm and Gribble damage: Detail of infestation damage in driftwood - comparing the generally distributed small burrows, caused by Gribbles, with much larger tunnels bored by Shipworm, from Rhossili, Gower, South Wales (5) 

Driftwood on the beach: Small piece of driftwood with holes made by Gribbles and Shipworms in situ as found on the sandy strandline at Rhossili, Gower, South Wales (6)

Driftwood damaged by sea creatures: Detail of infestation damage from wood-boring sea creatures: small tunnels by Gribbles and large tunnels and perforations by Shipworms. Driftwood from Rhossili, Gower, South Wales (7) 

 Revision of a post first published 29 May 2010

COPYRIGHT JESSICA WINDER 2011

All Rights Reserved

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7 thoughts on “Driftwood with holes made by Gribbles & Shipworms

  1. So bad for the boats, and yet the little gribbles are just trying to make a living. I’m glad they have a cute name, at least. Sorry to sound so shallow! But everything is beautiful when looked at for itself, isn’t it?

  2. “Gribble” sounds like something from a Dr Suess story, doesn’t it? They are a real pest because of their eating habits but I dare say they are quite cute in their own way. I haven’t seen one yet but I’ll post a picture when I do – then we can see whether they are beautiful or not.

  3. I can’t really remember! She was one of the nicer girls and I have very occasionally seen her when visiting my home town.
    I had an acquaintance at university who used to destroy any pens/pencils he was loaned by chewing them to nothing; I never loaned him anything again after I was presented with the remains at the end of a lecture. In my final year, he was sectioned as a result of a siege where he held one of the lecturers hostage to try and prove that he was Jesus Christ come back; the lecturer was an ex-monk… What larks, what larks!

  4. Viv, you have had some incredibly colourful experiences in your life. I hope that chewing wood is not a sign of madness – otherwise there are a lot of crazed gribbles, piddocks and beavers out there.

  5. Pingback: Common Piddocks – rock-boring molluscs | Jessica's Nature Blog

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