In general, larval were oval in shape when released. Measurements of Halichondria panicea from the Oosterschelde revealed that larvae varied from 180 by 340 mm up to 150 by 600 mm. The information in this section is taken from Wapstra & van Soest (1987) whose study focussed on demosponges from the Oosterschelde. Unlike Halichondria bowerbanki, Halichondria panicea survive the winter in a normal, active state in the Oosterschelde (Vethaak et al., 1982). A lifespan of about 3 years was suggested in Fish & Fish (1996). Wapstra & van Soest (1987) noted that the reproductive cycle in Halichondria panicea may vary considerably between areas. Vethaak et al. (1982) also observed that, in the field, newly settled colonies were apparent within one year, i.e. (1982) found, comparably, that large oocytes and embryos were present from mid-May until mid-August coinciding with an increase in water temperature from 12☌ to ca 19☌. They reported the species as being hermaphrodite although it was not stated whether or not the sponge was a permanent hermaphrodite or whether it exhibited protandrous or protogynous hermaphroditism.
However, Wapstra & van Soest (1987) reported that Halichondria panicea contained oocytes all year round in the Oosterschelde although embryos were only observed between May and September. Spermatogenesis occurred when mature oocytes were formed and larvae were released in the spring through to June. Oogenesis started in late summer/early autumn and oocytes developed overwinter. (1994) found that Halichondria panicea had a seasonally distinct, very short, reproductive period in the Kiel Bight, Western Baltic. Alander (1942, cited in Vethaak et al., 1982) recorded Halichondria panicea at 569 m depth off the Swedish coast. Burton (1959, cited in Vethaak et al., 1982) considered Halichondria panicea to be cosmopolitan in its distribution.
Habitat Information Halichondria panicea occurs in the intertidal zone to over 500 m. Lower circalittoral, Lower eulittoral, Lower infralittoral, Mid eulittoral, Sublittoral fringe, Upper circalittoral, Upper infralittoralĬobbles, Large to very large boulders, Small bouldersĮxposed, Extremely exposed, Ultra shelteredįull (30-40 psu), Reduced (18-30 psu), Variable (18-40 psu) Enclosed coast or Embayment, Estuary, Isolated saline water (Lagoon), Open coast, Ria or Voe, Sea loch or Sea lough, Strait or Sound
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