A member of the ragworm family, but rather rarer, the rockworm is found only in chalk rock, living in small sand-lined burrows and crevices. Similar to the king rag, but much smaller at about 8cm long, it is a bright brown/orange colour. It looks much like its close relative the small ragworm found inside the shells of hermit crabs.
Noted for its toughness, the rockworm is exceptionally lively and is particularly effective for pier pollack, pouting and scad. At the same time it is something of a specialist bass bait in chalk cliff regions. All the flatfish also find the rockworm’s wriggly tail irresistible. Mostly favoured as a sight bait or for tipping off other baits, it works best in clear water and when fished off the sea bed.
First find your worm
Locating rockworm is often a matter of trial and error, although in most cases the worms inhabit the same areas of chalk rock as the piddock clam.
Find some white chalk cliffs and there will inevitably be rockworm where the sea meets the chalk. The worms five higher up the tide line than the clams but tend to overlap them towards the shoreline, favouring the inner undercliff rocks and plateaux covered with green weed.
The limited number of chalk cliffs around the British Isles restricts rockworm to a few places. Thanet in Kent and Beachy Head in Sussex are the worm’s two main strongholds. There are also favourable chalk cliff habitats for rockworm along the north Norfolk coast and the coasts of Dorset and Lincolnshire.
Digging them up
It’s easiest to use a small hand pick or a hand fork to dig for rockworm. The entrance to the burrows can be seen quite clearly – you will find that they tend to be on top of ridges or rock among the humps and hollows, along fault lines or at the edge of a ridge.
If you are using a fork, collect the worms by chipping off the humps and corners of a ridge. This can be a messy business since the chalk and spray splash everywhere. A hand pick is useful for removing the worm from its burrow once small lumps of chalk are broken off. The worm tends to curl up in a ball and can be removed by splitting the piece of chalk with the pick so that the split passes through the burrow.
Once dug, keep the worms required for immediate use in a bowl or box of green weed and dry tissue paper. If you want to keep them alive for longer, transfer them to a shallow tray filled with sea water and put it in the fridge.
Fishing with rockworm
You can fish rockworm singly or in fat dan-gly bunches, passing the hook point through the worm’s head end only. It is superb fished on booms alongside pier walls or piles, and it can take thin-lipped mullet, garfish, mackerel and even herrings from some south coast piers.
Rockworm is such a tough customer that even when hooked through the head it can withstand forceful casting. Dunking the worm in the sea before casting also helps — as with harbour rag, it makes the worm contract and so harden.