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of P. elegans within micro-scale patches. For example, the potential feeding area of
P. elegans is likely to have been over-exploited within these localised patches (Brey,
1991) and since spionids are known to predate on settling larvae of other species
(Breese and Phibbs, 1972; Daro and Polk, 1973; Tamaki, 1985; Whitlatch and Zajac,
1985) there may have been no refuges from predation for settling larvae. However,
such interactions would presumably have resulted in significant negative associations.
It was not possible to determine sediment heterogeneity along each transect in this
study. Therefore, correlation analysis between the abundances of adult and juvenile P.
elegans with the measured sediment variables (% water, % organic and % silt/clay
contents) were not possible. P. elegans patches appeared as smooth plateaus with no
visual sign of topographical variability within them. Samples taken from 3 patches
during February 1998 revealed micro-scale spatial patterning of the 3 sediment
variables. These sediment patches were at least 3cm 2 with apparent correlation
between at least 2 of the variables in 2 of the 3 replicates. These patches were not of
the same scale as patches exhibited by adult P. elegans or by new recruits during most
of the study period (less than 3cm2), however, sediment patterning of this scale for
other variables, or for these variables during other times of the study period cannot be
ruled out. The possibility that micro-scale patchiness of P. elegans was generated by
aggregated larval settlement patterns in response to sediment heterogeneity cannot be
falsified with the results from this study.
Although P. elegans is a sessile tube-building spionid, adults of this species may be
capable of some mobility. Armonies (1994) found adult P. elegans individuals in the
water column, and Wilson (1992, 1994) suggested that adults of this species were
capable of lateral crawling. P. elegans is the only reported spionid species in which
direct spermatophore transfer is used during sexual reproduction (Schlotzer-
Schrehardt, 1987, 1991). This involves a special pattern of reproductive behaviour
including active seeking of the females by males and therefore adults may actively
seek to relocate near conspecific individuals to enhance their reproductive chances.
This factor may also have been partly responsible for the micro-scale aggregations of
adults observed in this study, at least at certain times during the year. Direct
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