Habitats

Balanoglossus live in continental shelf,island and reefs areas, in mud or shallow sandy flats of intertidalregions (Mertz 2004). Even though they can occurin deep waters, like abyssal plains (Mertz 2004), they are mainly found belowthe surface of the ocean bottom, in a burrow (Bateson, 1883).

The burrow is U-shaped (figure 5) and is usually at a depth of around 30 – 75cm(Biocyclopedia, 2012; EcoMarines 2013). It has two openings separated from each other fromapproximately 10 to 30 cm (Biocyclopedia,2012). Generally they stay with the proboscis stand out in one of the openings,but they might also stay for a long period underground (Mandal,2012).  Usually, Balanoglossus can befound with its body curled up in spiral, similar to a corkscrew (Bateson, 1883).Their epidermal secretions helps to give strength to the burrow walls strong (Mertz 2004).

Figure 5 - Balanoglossus sp position on the sediment (Rachel, 2012)

There are some species that can also live under rocks (Biocyclopedia,2012), inthe sand insideshells, in dense seaweed, or in the middle of roots (Mertz 204).