218
A. DE DECKER:
Abundant species such as Calanoides carinatus or Centropages br.achiatus were found
to have their youngest copepodite stages concentrated in relatively small areas, mostly
around centres of upwelling, from where the later stages diverged further afield as they
progressed in age. Such "nurseries" were found both inshore and over the shelf edge, the
latter position probably denoting cyclonic eddies (Fig. 11 a - q). When comparing the
distribution of the various species identified over the Bank, a number of patterns can be
distinguished, as enumerated below (Fig. 12 a - q).
a) Species common in regions adjoining the Bank and also present over the latter,
without showing a noticeable increase in abundance:
Calanoides carinatus
Paracalanus parvus
Centropages chierchiae
Rhincalanus nasutus
Nannocalanus minor
b) Species occurring in adjoining regions, but showing a notable increase in abundance
over the Bank:
Calanus finmarchicus s.l.
Candacia bipinnata
Ctenocalanus vanus
Clytemnestra rostrata
Pseudodiaptomus nudus
Euterpina acutifrons
A number of species of groups a and b tend to follow the coastline eastward as far as
Durban and beyond, while becoming scarcer with distance from the Bank. They are
obviously carried by the cold countercurrent.
c) Species avoiding the Bank but commonly found on the edge of the shelf and beyond:
Neocalanus gracilis
Pleuromamma abdominalis
Eucalanus elongatus
P. borealis
Eucalanus mucronatus
P. piseki
Mecynocera clausi
P. xiphias
Undeuchaeta plumosa
d) Species found only in a relatively narrow inshore belt between the Cape and
Durban. Most of them seem to enter the area coming from the Indian Ocean and are
listed below in order of westward extension along the coast.
Candacia truncata
Labidocera acuta
Clytemnestra scutellata
Canthocalanus pauper
Cop ilia mirabilis
Temora turbinata
Candacia catula
Paracalanus aculeatus
Centropages calaninus
Clausocalanus furcatus
C. gracilis
Paracalanus crassirostris
e) Species widespread in the surveyed region of the Indian Ocean and extending
westward over the Bank in the inshore belt only (in order of westward penetration):
Acrocalanus monachus
Calocalanus contractus
Euchaeta acuta
Microsetella rosea
E. wolfendeni
M. norvegica
Groups d and e seem to imply longshore transport in the opposite direction from
groups a and b.
A. DE DECKER:
Abundant species such as Calanoides carinatus or Centropages br.achiatus were found
to have their youngest copepodite stages concentrated in relatively small areas, mostly
around centres of upwelling, from where the later stages diverged further afield as they
progressed in age. Such "nurseries" were found both inshore and over the shelf edge, the
latter position probably denoting cyclonic eddies (Fig. 11 a - q). When comparing the
distribution of the various species identified over the Bank, a number of patterns can be
distinguished, as enumerated below (Fig. 12 a - q).
a) Species common in regions adjoining the Bank and also present over the latter,
without showing a noticeable increase in abundance:
Calanoides carinatus
Paracalanus parvus
Centropages chierchiae
Rhincalanus nasutus
Nannocalanus minor
b) Species occurring in adjoining regions, but showing a notable increase in abundance
over the Bank:
Calanus finmarchicus s.l.
Candacia bipinnata
Ctenocalanus vanus
Clytemnestra rostrata
Pseudodiaptomus nudus
Euterpina acutifrons
A number of species of groups a and b tend to follow the coastline eastward as far as
Durban and beyond, while becoming scarcer with distance from the Bank. They are
obviously carried by the cold countercurrent.
c) Species avoiding the Bank but commonly found on the edge of the shelf and beyond:
Neocalanus gracilis
Pleuromamma abdominalis
Eucalanus elongatus
P. borealis
Eucalanus mucronatus
P. piseki
Mecynocera clausi
P. xiphias
Undeuchaeta plumosa
d) Species found only in a relatively narrow inshore belt between the Cape and
Durban. Most of them seem to enter the area coming from the Indian Ocean and are
listed below in order of westward extension along the coast.
Candacia truncata
Labidocera acuta
Clytemnestra scutellata
Canthocalanus pauper
Cop ilia mirabilis
Temora turbinata
Candacia catula
Paracalanus aculeatus
Centropages calaninus
Clausocalanus furcatus
C. gracilis
Paracalanus crassirostris
e) Species widespread in the surveyed region of the Indian Ocean and extending
westward over the Bank in the inshore belt only (in order of westward penetration):
Acrocalanus monachus
Calocalanus contractus
Euchaeta acuta
Microsetella rosea
E. wolfendeni
M. norvegica
Groups d and e seem to imply longshore transport in the opposite direction from
groups a and b.