Bowerbank's Halichondria is easy to confuse with the breadcrumb sponge. Older specimen have long thin, stringy branches which emerge from a thin crust. Young specimen lack these stringy branches. Since the Delta Works were built, Bowerbank's Halichondria is found more often than the breadcrumb sponge. It used to be the other way around. But this sponge is more resistant to mud. Bowerbank's Halichondria is also known as crumb-of-bread sponge or the common sponge.

This demosponge species is either encrusting, branching, or forms flattened lobes. The skeleton is composed of irregularly and loosely packed, siliceous spicules. Spicule type includes megascleres (oxeas) only, measuring 170-300 mm in length. Color variants include gold, yellowish-tan, or olive-brown; surface is often translucent. For complete description, see Lee et al., 2007.

 The growth form is variable (see General biology) from thinly to massively encrusting, with tassel-like irregular branches which form flattened masses. Colonies can be up to 25 cm across with branches reaching 12 cm high. Its colour is beige to dull brown in the summer, and light grey/yellow in the winter. Halichondria bowerbanki typically turns a characteristic yellow-orange when spawning because of the colour of the larvae. There are no obvious large exhalent openings (oscules) present and the surface is smooth or uneven with a breadcrumb-like texture.

• Microscopic examination of the spicules reveals that they are relatively long and thin, and taper to the apices.
 
• Named after James S. Bowerbank (1797-1877), a pioneering authority on sponges.
 
• Easily confused with Halichondria panicea but Halichondria bowerbanki is distinguished by the absence of the chimney-like oscules that occur in Halichondria panicea.

This sponge can be very polymorphic, varying from a cushion to almost a branching-repent form. A cushion can give rise to oscular chimneys with oscules at the top or, more typically, to a profusion of simple, solid, tassel-like branches with the oscules mainly along their length (cf. Halichondria panicea). In some sheltered localities the branches grow over other organisms and loop like bramble stolons, attaching to any suitable object they encounter. The colour is usually buff or cream, never green. The variable nature of Halichondria bowerbanki can make it very difficult to identify positively. The most likely confusion is with Halichondria panicea. The growth of tassels in H. bowerbanki seems to be a good character, but these are not present all year round. H. bowerbanki lacks the green colour that is present in H. panicea in well lit conditions and also the characteristic smell.

Celtic Seas, Gulf of Maine/Bay of Fundy, Gulf of Mexico, North Sea, South European Atlantic Shelf, Southern Norway, United Kingdom, United Kingdom Exclusive Economic Zone, Virginian

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Halichondria bowerbanki has been introduced to the Northeast Pacific, with confirmed records from British Columbia to central California. This species is native to the Northeast Atlantic, distributed from the Bay of Fundy to Cape Hatteras.

A common species in the British Isles.

In the Northeast Pacific, Halichondria bowerbanki is most similar to H. panicea (Pallas, 1766).

Depth range based on 109 specimens in 1 taxon.
Water temperature and chemistry ranges based on 23 samples.

Environmental ranges
  Depth range (m): 0 - 108
  Temperature range (°C): 11.054 - 24.233
  Nitrate (umol/L): 0.501 - 8.267
  Salinity (PPS): 34.903 - 36.315
  Oxygen (ml/l): 4.476 - 6.346
  Phosphate (umol/l): 0.100 - 0.838
  Silicate (umol/l): 0.805 - 5.123

Graphical representation

Depth range (m): 0 - 108

Temperature range (°C): 11.054 - 24.233

Nitrate (umol/L): 0.501 - 8.267

Salinity (PPS): 34.903 - 36.315

Oxygen (ml/l): 4.476 - 6.346

Phosphate (umol/l): 0.100 - 0.838

Silicate (umol/l): 0.805 - 5.123
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Marine; bays and harbors, on floats

 Present on rocky surfaces in the shallow subtidal, with occasional intertidal specimens under overhanging rocks. Halichondria bowerbanki occupies wave-sheltered, sediment-rich environments. It often grows intertwined with hydroids and algae and may be common in estuaries. May occur in areas sheltered from strong tidal flow through to tidal sounds.

On rock or other animals, even ascidian tests. It reaches its maximal development in harbours and estuaries, being very tolerant of muddy and brackish conditions where it tends to replace Halichondria panicea (but there are reports of both species occuring together in silty conditions).

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: GNR - Not Yet Ranked