Lobster burrows in Swedish waters
- B. I. Dybern1
© Biologischen Anstalt Helgoland 1973
1. The typical habitat of the European lobster(Homarus vulgaris) is rocky or soft bottom with crevices, boulders and stones.
2. At the Swedish west coast it favours a bottom with stones and boulders on sand or shellsand, where it can dig burrows in the soft bottom material under the stones or boulders.
3. Such burrows have one, or more than one, opening; in the latter case usually two. A relationship between the size of a lobster and its burrow is often, but not always, noted. The lengths of tunnel-formed burrows, for instance, vary with the size of the overlying stones.
4. External factors more or less important in the choice of the site of a burrow are, for example, the composition of the bottom material, the occurrence of slightly overhanging edges of stones or rocks, an outwards-downwards sloping bottom, highest possible values of salinity and temperature, and a sparse algal vegetation or no vegetation at all. Lobsters tend to be absent from polluted areas where the sedimentation rate of organic particles and the turbidity of the water are high.
5. Besides being shelters, the burrows also serve as look-outs.
6. Burrows may be dug in soft-bottom material in rocky crevices or in flat mud bottoms.
7. The burrowing behaviour is characterized by three main patterns: (a) loosening of the bottom material with the walking legs and sometimes with the big claws, (b) shuffling off of piles of soft bottom material in a “basket” formed by the 3rd pair of maxillipeds and one or two pairs of walking legs, and (c) fanning backwards with the pleopods.
8. Small lobsters behave like adults.
9. The burrowing behaviour is very similar to that of the American lobster and resembles that ofNephrops norvegicus.