Biological survey of Sandvis 1,
introduction and faunal list
by
Brian F. Kensley
South African Museum
Cape Town
M.J. Penrith
State Museum
Windhoek
Abstract - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 I
I Introduction 181
2 Collecting areas and methods 183
2.1 Hard substratum 183
2.2 Sand 183
2.3 Mud 183
2.4 Sand-mud mixtures 183
2.5 Shell 183
3 Acknowledgements 186
4 References 186
The topography of Sandvis is briefly introduced and changes
in the area, based on charts, described. These show that the
area has evolved, within 90 years, from an open harbour,
suitable for large craft, to an almost completely landlocked
generally shallow lagoon.
A faunal list of the aquatic and marinal fauna is given. Ex-
cluding the planktonic component a total of 93 invertebrate
and 25 vertebrates are recorded.
During 1974 the authors were asked by the Nature Conserva-
tion and Tourism Division to undertake a survey of the
marine invertebrates and fishes of Sand vis, to establish inter
alia its ecological importance and need for protection. The
results of this survey will be published as a series. Part I
describes the area in broad detail and contains a faunal list of
the marine animals. Part 2 will deal in detail with the distribu-
tion and numbers of intertidal invertebrates. Subsequent
reports will consider the distribution and biomass of subtidal
invertebrates, the biology of the fishes, and the physical
parameters.
Sandvis, or Sandwich Harbour (formerly Port D'Ilheo) is a
large body of generally shallow water situated at approximate-
ly 23?20'S 14?25'E, some 50 km south of Walvis Bay. It is
11, I kilometres long by 3,3 kilometres wide at its widest part.
(fig. I), with the long axis running roughly north-south. To the
east the lagoon is bounded by high sand dunes of the central
Namib system, along much of the eastern edge these dunes
run directly into the lagoon. In the south-east corner the line
of dunes is at an angle to the coast line and the dunes are
separated by pools of seepage water and channels only open
to the lagoon at high tide. The western side consists of a sand
bar separating the lagoon from the sea. There are extensive
shallows on the lagoon side of most of the sand bar. Although
the lagoon has been known to be completely closed off to the
sea (de la Bat pers comm) this has not occurred during the sur-
vey. The position and form of the mouth, however, is con-
tinually changing. In general it varies from a roughly central
position to an opening at the northern half.
An extensive damp salt pan lies to the south of the lagoon,
which appears devoid of macroscopic life apart from the in-
sect Heterocerus peringueyi. The northern end is a large area
of mud flats interspersed with pools and drainage channels.
Above H.W.N. there are extensive beds of the halophyte
A rthrocnemum and Sporobolus grass.
The high dunes of the land protect Sandvis from easterly
winds. The dominant winds (at least 6 hours on 90% of days)
are southerly, however, and the salt pan provides no protec-
tion. This wind combined with the shallow water results in a
very rough sea on most afternoons. The temperature within
the lagoon due to solar warming is always higher than the sea
outside. The degree of warming is dependant on several fac-
tors: apart from sunshine, air temperature, fog, evaporation
and the time of high tide are all important. In general the
temperature within the body of the lagoon is some 5-6?C
above the ambient sea temperature in summer and 2-3?C in
winter. In the semi-isolated pools of the northern mud flats
and gulleys near the south end, much higher temperatures can
occur. Sea temperatures, measured at the mouth on an incom,
ing tide, normally range between 12?C and 16?C; however,
since the low water temperatures are dependant on wind in-
duced upwelling, wide variations can occur, and sea
temperatures in the area within the range of lOoC and 2 1?C
occur.
Sandvls. General features. mouth not shown. Dark stippling: dry land. Light stippling: less than I metre L.W.S.T. Horizontal hatching: salt pan. M: alternate posi-
~Mdmoo~.X:A~p~De~hs~mwRD~wKoo~~~hs~w8m~resm~o~urint~~~nitYd~t:h:e~c:u:r~r:~:'t~m:(:)u:t:h:. ~~ ~ ???????????????
Initial water analysis suggest that underground seepage of
freshwater has little effect on salinities and that Sandvis is best
considered as a marine lagoon.
The higher temperature of Sandvis relative to the surrounding
coast line has resulted in a number of animals becoming es-
tablished outside their normal range.
Sand vis was a well known anchorage in the days of sail and is
believed to have been used as a careening base by pirate ves-
sels. It was certainly used for this purpose later by whalers
both British and American. Near the end of the 19th century
there was an ill-fated attempt to establish a meat canning fac-
tory there, while the Cape Town firm of de Pass & Spence
operated a fishing station for many years. Later a company
held the rights to collect guano.
Today it is difficult to imagine Sandvis being used as an
anchorage for large vessels. The topography of Sandvis has
however, undergone marked changes in the last 100 years.
When surveyed in 1880 by Lt. C.F. Oldham in H.M.S. Sylvia,
the northern end of the lagoon was an open bay with a depth
of 5 fathoms. By 1892 the sandspit had extended northwards
considerably and a bar of 10 foot was reported at the mouth.
Later silting in the northern end continued. This was probably
accelerated during the tenure of the guano company since, to
increase the roosting areas and thus the guano yield, they used
sandpumps to create artificial sand banks.
Due to its isolation very little marine biological work has been
done at Sandvis. The only previous word was Lucks' (1970)
study on the steen bras, Lithognathus aureti. Nothing was
known regarding the species composition of the invertebrate
fauna.
Unfortunately during the course of this survey a short list of
marine animals, randomly collected at Sandvis was published
(Stuart 1975). The work has many inaccuracies and areas are
vaguely defined. This is especially true of the beach which in-
cludes items washed up. Most serious however, is that in the
mollusc list certain species are listed as dead shells, implying,
to anyone not familiar with the area, that all other animals
were collected alive in the habitats listed. This is certainly not
always true. Among other dubious records Stuart lists Ostrea
atherstonei Newton from the sand bar. For a living animal
this would be both geographically and ecologically an excep-
tional record. We believe this record to refer to dead, beach
rolled valves of Hinnites sp. which are common on the sand
bar but having their origin well away from Sandvis.
The present faunal list records intertidal and benthic in-
vertebrates and aquatic vertebrates. In addition parasitic
animals and some of the larger planktonic invertebrates are
listed but no attempt has been made to include the copepods
and other smaller zooplankton. Birds, although in many cases,
important in the marine ecosystem of the area, are not in-
cluded. A detailed report on the birds has recently been
published (Berry & Berry 1976). In all cases only material col-
lected alive, and seen by us is listed.
2 COLLECTING AREAS
AND METHODS
The main hard substratum consists of three ridges of rock
projecting from the dunes and exposed at low water. Other
hard substrata for settling organisms are an iron cylinder
north of the rocks, and the old wreck site to the south. This
last consists of a scattering of iron work, bricks, bottles, cattle
bones etc. lying between H.W.N. and L.W.S. It is assumed
that these are connected with the illfated meat factory. In cer-
tain areas a secondary hard substratum fauna occurs where
animals have settled on large Perna which themselves are
anchored in mud or sand.
Coarse sand of marine origin occurs on the beach to seaward
of the sand bar and in places on the lagoon side of the bar, es-
pecially in the region where the current mouth is. In the mouth
area and outside the bar the sublittoral sand is very hard
packed, probably by a combination of wave action and scour
on the ebbtide.
Finer sand originating from the dunes occurs along much of
the eastern edge. At the southern end, wind blown sand of
dune origin forms a low ridge between the pan and the lagoon
and overspills into the lagoon due to the prevailing wind.
In the main lagoon mud occurs wherever the depth exceeds
about 2 metres L.W.S. These areas are referred to as green
mud, the bottom consisting of very soft mud matted together
with the tubes of amphipods of two species of Ampelisca.
The northern portion of the lagoon forms extensive mud flats
exposed at low water except for semi-isolated pools and
drainage channels. The higher portions of the mud banks are
covered with dense growths of Arthrocnemum and
Sporobolus, the former sheltering vast numbers of Assiminia
snails. Unlike the green mud areas, this mud is very hard
packed and often contains large numbers of dead bivalve
shells, especially Dosinia and Lutraria.
There are extensive areas of the lagoon where the depth is less
than 2 metres L.W.S. Most of these areas consist of sand-mud
mixtures. The physical constitution of the substratum varies in
different areas due to influence of scour action, aeration and
sand/mud ratios. This has resulted in differences in the domi-
nant fauna of the different areas. They have been named for
their dominant faunal constituent. (Map 3).
At the southern end, and to the south of the large Eastern
bank there are areas of dead shell, mostly Dosinia. These are
presumably the results of earlier mass mortalities.
Wherever possible collecting was done by hand, either direct-
ly on hard substratum or by means of digging and seiving on
soft substratums. Below L.W.S. most collecting was done by
dredging from a dinghy. Fish were collected by gillnetting,
seining and hand nets, depending on habitat.
w (J1(J1 ~ (J1 ~~ N ..N
~ -A
W WW ;:;:~ 1I.J.. W
W ;:;: W~.. W ;;:::....? ;:;: W~.. W ;:;:
????N ;:;: W
W ~ ~;:;: -A ~W N(J1 ;:;:;:;: ~N 1I.J
e::::'
>< 1111111 ",- '"Z ~ Cl }> "" '" c>0 c ro '" "0 or 0;; ; 0 '" 0 n:: CL '" OJ "0 "or OJ 0 (Q 0'" '" OJ '":; 0 ~ 0OJ C 0~ CL CLc
CL
Sandvis. Showing main marine ecological areas. Shell: areas of broken shell, large numbers of Allthothoe and Tapes. Sponge: Ciocalypta and associated boring and
surface organisms. Perna: Perna perna with attached week, smaller animals in weed. Asterina: Asterina luderitzialla and pelecypoda. Green mud: Ampelisca spp.
dominate. Mud sand: low biomass, pelecypod a and Diopatra. Northern mud: high biomass, pelecypoda and polychaeta.
The paper is published with the permission of the secretary for
National Education.
The survey was initiated by the Director of Nature Conserva-
tion and Tourism with the active co-operation of his staff. We
especially acknowledge the help of Messrs. John Dixon and
Charles Clinning, who, if not "hewers of wood and drawers of
water", certainly provided these two very necessary items
along with whole-hearted co-operation in many ways.
The field work has been made possible with the co-operation
of the Directors of the South African Museum and the State
Museum. In addition to Messrs. Clinning and Dixon, the fol-
lowing, all members of the State Museum staff assisted in field
work: Dr. M.L. Penrith and Messrs. A. Simoes & E.
Makgoabone. We are grateful to Dr. N.A. Millard for the
identification of some Coelenterata and Mrs. J. Day for cuma-
cean identifications. Copies of various interesting old charts of
Sand vis, were kindly supplied by the Hydrographer of the
South African Navy, Capt. A. Fawthrop.
BERRY H.H. and BERRY C.U.
1976: A check list and notes on the birds of Sandvis, South West
Africa.
Madoqua 9 (2) 5-18
LUCKS O.K.
1970: Aspekte van die witsteenbras
Lithognathus aureti Smith 1962 in die Sand vis Strandmeer.
MSc Thesis University of Stellenbosch (Unpublished)
PENRITH M.J.
1976: The first confirmed record of Lithognathus lithognathus sym-
patrie with L. aureti (Pisces Sparidae) Madoqua 9 (3): 53-54.
STUART C.T.
1975: Marine fauna collected at Sandvis, Namib Desert Park, South
West Africa. Madoqua (II) 4: 101-102.
SPECIES LIST
SPECIES OCCURRENCE AT
SANDVIS
MOLLUSCA
GASTEROPODA
Very abundant in northern weed-flats,
especially in Arthrocnemum
Taxonomic positIon very uncertain
On sandbar at lagoon mouth
On sandbar at lagoon mouth; dredged from mud
in channel near mouth
Present in Perna area near mouth, 8 m
Bullia digitalis Meuschen
Bullia laevissima (Gmelin)
Gibbula benzi (Krauss)
Lillorina knysnaensis Philippi
Fairly common in Perna area near mouth, 8 m
Juveniles abundant on rocks, adults
abundant in weeds at northern end
Common in weed beds at northern end
Common in sand/mud at bases of weed,
especially A rthrocnemum
Fairly common in starfish area; common in
channel near mouth; in mud around rocks
Fairly common starfish area
Common in mud around rocks; dredged from
mud in channels and from Perna area
Present on rocks
Fairly common on rocks
Abundant on rocks
Nassarius plicatellus (Adams)
Natica villata Gmelin
Patella granatina Linnaeus
Patella granularis Linnaeus
Siphonaria capensis Quoy & Gaimard
MOLLUSCA
Pelecypoda
Rare on rocks; fairly common in starfish
area attached to algae
Present on rocks; many juveniles attached
to algae 8 m
Rare in sandbar at mouth; abundant on
sea-beach
Abundant in mud flats and sand at
northern and southern end; present in
starfish area and Perna area
Present in northern mud flats
Rare on rocks and in algal area
Abundant in northern mud flats
Gastrana matadoa (Gmelin)
Gregariella barbatella (Cantraine)
Leporimetis hanleyi (Dunker)
Common in coarse sand at southern end:
dead in situ at northern end
Port Elizabeth to Liideritzbucht
Port Elizabeth to Liideritzbucht
Natal to False Bay; Mowe Point;
Baia dos Tigres
East London to Saldanha Bay
Natal to Rocky Point, S.W.A.
Camps Bay, Cape; Tristan da Cunha;
Gough Island; Dassen Island;
Port Alfred to False Bay
Port Alfred to Table Bay; Rocky Point,
S.W.A.
Table Bay to Mocamedes
Morocco to Senegal
Agulhas to Rocky Point, S.W.A.
Zululand to Mocamedes
Natal to Rocky Point, S.W.A.
Port Alfred to Rocky Point; Straits of Magellan;
Falkland Islands; Kerguelen Island
Port Alfred to Mowe Point
Bushmans River to Walvis Bay; Baia dos Tigres
to Senegal
lnhaca Island to Still Bay; West Africa
Natal to Cabo Negro, Angola; Mediterranean
Known as Pleistocene fossil from Redhouse,
Knysna, Sedgefield; taxonomic position
uncertain
Natal to Liideritzbucht, Mediterranean;
possibly West Africa
Amphipholis squamala (Delle Chiaje)
ASlerina luderilziana Doderlein
Ophiolhrix Iriglochis Miiller
Parechinus angulosus (Leske)
ARTHROPODA
INSECTA
Diopalra neopolilana neopolilana
Della Chiaje
Eulalia sanguinea Oersted
Harmolhoe aequisela aequisela
(Kinberg)
Lumbrineris lelraura (Schmarda)
Nereis (Neanthes) succinea
Frey & Leuckart
Nereis (Nereis) falsa
Quatrefages
Paleanotus chrysolepis Schmarda
Phyllodoce castanea
(Marenzeller)
Phyllodoce schmardei Day
Platynereis dumerilii
(Audouin & Edwards)
Pseudonereis variegata (Grube)
Scolelepsis squamata (Miiller)
Scoloplos (Scoloplos) sp.
Syllidea armata Quatrefages
Abundant on rocks; many juveniles on algae at
8 m; in mud channel at northern end
and in starfish area
Fairly common amongst barnacles on
rocks; in rusty iron ruins of wreck
Abundant on rocks; on algae at 8 m
Common on sandbar at mouth; in mudflats at
northern and southern end; rare on rocks;
fairly common in starfish area and
amongst algae
Present on sandbar at mouth; fairly
common on sea-beach
Fairly common in starfish area
Abundant in channel and starfish
area, present on Perna in channels
Fairly common in starfish area
Fairly common in starfish area
Abundant in upper layer of mud/organic
detritus in northern mud flats
Abundant in crevices in rocks and
in mud flats at low tide
Abundant in mud banks at northern
and southern end
Abundant in northern and southern mud
flats; from mouth to sand dune bases
Common in starfish area
Common in southern mud banks, and
sand bank close to sea beach
Fairly common in Perna and starfish
areas 8m
Common in mud banks
Fairly common in northern mud banks
Present in Perna area; fairly common
in starfish area
Common amongst Perna on rocks
Taken in plankton
Taken in plankton
Present in Perna area
Mocambique to Table Bay; Yzerfontein; Meob Bay
to Mocamedes; Mediterranean; West Africa;
Brazil; Straits of Magellan; Red Sea
Inhaca Island to Walvis Bay
Meob Bay to Angra Fria, S.W.A.; Ecuador;
Chile; Juan Fernandez Island
Natal to Rocky Point; Mediterranean;
West Africa to Angola
Mocambique to Liideritzbucht
Liideritzbuchtto Torra Bay
East London to Liideritzbucht
Zululand to Rocky Point
Cape to S.W.A.; Subantarctic; Australia;
New Zealand; Japan; Mediterranean; Europe
Mocambique to S.W.A.; Europe to West Africa;
Indo-Pacific
Natal; S.W.A.; Mediterranean
Mocambique to Cape; Rocky Point; cosmopolitan
in tropical and temperate waters
Mocambique to S.W.A.; Mediterranean to West
Africa; Tristan da Cunha; Madagascar, Persian
Gulf; Japan
Natal to S.W.A.
Natal to S.W.A.; cosmopolitan in tropical
and temperate waters
Natal to S.W.A.; Norway; Mediterranean
to Angola
Natal to S.W.A.; North Sea; North and
South Atlantic; Pacific
Natal to S.W.A.; Mediterranean to West
Africa; Madagascar
Natal to S.W.A.; Madagascar; Australia;
Chile; California to Alaska
Mocambique to Rocky Point; Indo-Pacific
False Bay
Natal to S.W.A.; cosmopolitan in tropical
and temperate waters
Mocambique to S.W.A.; circumtropical
Mocambique to S.W.A.; Mediterranean to West
Africa; Indo-Pacific
Electra verticil/ata
(Lamouroux)
CRUSTACEA
CIRRIPEDIA
CRUSTACEA
CUMACEA
CRUSTACEA
MYSIDACEA
Mesopodopsis slabberi
van Beneden
CRUSTACEA
LEPTOSTRACA
CRUSTACEA
COPEPODA (Parasitic forms only)
Brachiella lithognathae
Kensley & Grindley
Caligus engraulidus Barnard
CRUSTACEA
ISOPODA
Exosphaeroma laeviusculum
(Heller)
Idotea indica H.M. Edwards
Nerocila orbignyi
(Guerin-Meneville)
Niambia truncata (Brandt)
Pontogeloides latipes
Barnard
Abundant in patches in southern
shallow end of lagoon
Common on rocks and amongst ruins
of wreck
Common on rocks and in Perna area
near mouth
Abundant on rocks
Common in plankton; taken from stomach
contents of Argyrosoma
Common in plankton; taken from stomach
contents of grebe and Trachurus
Fairly common in algal area;
taken in plankton
Taken from stomach contents of
Argyrosoma
From Mugil cephalus; Hypacanthus amia;
free-swimming in plankton
On Diplodus sargus; Lithognathus aureri;
Argyrosoma hololepidorus
From Triakis megaloprerus
Common in sea-embayment where
new mouth is forming
Between mytilids on rocks
Present amongst algae 8 m
Free-swimming in plankton; parasitic
on Mugil, Thyrsites
Abundant in A rthrocnemum and other
weed patches under bushes along
shore
Free-swimming in pools; burrowing in
detritus; common in sand at sand
dune bases
Common on sand dune beach, and on
inner (land) side of sea beach sandbar
Mocambique to Cape; Liideritzbucht to
tropical West Africa
Table Bay to Rocky Point
Agulhas to SI. Helena Bay;
North Africa
Port Elizabeth; southern Cape; Namaqualand;
Walvis Bay; Okahandja
CRUSTACEA
AMPHIPODA
Amaryllis macrophthalma
Haswell
Ampelisca brevicornis
(Costa)
Ampelisca palmata Barnard
Abundant in mud flats, especially
below low tide level
Abundant in mud flats, especially
below low tide level
Fairly common in starfish areaErichthonius brasiliensis
(Dana)
Lembos hypacanthus Barnard Abundant in Perna area, in sponge
Ciocalypta and in starfish area
Abundant in starfish area and Perna area;
fairly common in sponge Ciocalypta
A bundant in Perna area
Common in Perna area
Common on sand dune beach
Paramoera capensis (Dana)
Photis longimanus Walker
Talorchestia quadrispinosa
Barnard
CRUSTACEA
DECAPODA
Hymenosoma orbiculare
Desmarest
Abundant in mud-bottom areas, in Perna
and starfish area, in weed pools,
in Arthrocnemum patches
Fairly common in channel near mouth
From Mustelus gut (probably does
not occur in lagoon)
From Mustelus gut; fresh dead
specimens washed ashore
Abundant in algal area and northern
channel
Abundant in algal area and northern
channels, common in night plankton
Fairly common amongst mytilids on
rocks, in algal area
Fairly common amongst rusty ruin
of wreck
Macropetasma africana (Balss)
Nautilocorystes ocellata
(Gray)
Ovalipes punctatus
(de Haan)
Palaemon (Palaemon) pacificus
Stimpson
Pa/aemon (Pa/aemon) pacificus
Stimpson
Pilumnoides per/atus (Poeppig)
Upogebia capensis
(Krauss)
Aglaophenia pluma dichotoma
(M. Sars)
Anthothoe stimpsoni
(Verrill)
Bunodosoma capensis (Lesson)
Koellikerina cffasciculata
(Peron & Lesueur)
Pleurobrachea sp.
Abundant in Perna and especially starfish
area, and on rocks
Common around rocks
Present in plankton
VERTEBRATA
PISCES
CHONDRICHTHYES
Mustc.'lIs mus/elus
(Linnaeus)
Triakis megalopten"
(A. Smith)
Rhinobates blochi
Muller & Henle
M.I'/iobates aquila (Linnaeus)
Das.l'atlispas/inaclls (Linnaeus)
Callorh.l'nchlls capensis Dumeril
Less common than preceeding species.
Again usually gravid 9 9
Abundant in all shallow areas
Seasonally abundant in mid water
Shallow water over banks. Uncommon
Rare
Engralilis capensis
Gilchrist
Sardinops ocellQtQ
(Pappe)
Small schools of juveniles
occasionally in lagoon
Not Common
Mocambique to Olifants River;
circum tropical
Natal to S.W.A.
Natal to S.W.A.; austral
Port Elizabeth to S.W.A., Indo-Pacific
False Bay to S.W.A.
Mocambique to southern Angola;
Zanzibar
Natal to False Bay; Swakopmund
Port Elizabeth to Walvis Bay
Natal to Liideritzbucht; austral
and Indo-Pacific
Mocambique to Rocky Point; Indo-Pacific
False Bay to Rocky Point; Panama; Chile;
North Atlantic
Mossel Bay to Liideritzbucht
East London to S.W.A.; Mediterranean
to West Africa
Durban to Liideritzbucht
Transkei to Liideritzbucht
West Africa and Mediterranean
England to South Africa
Baltic to South Africa
South Africa
TachysurusJeliceps
(Valenciennes in C & V)
Lichia amia (Linnaeus) Pelagic. Always present, possibly an
isolated population
Always present but numbers varyTrachurus trachurus
(Linnaeus)
Pomatomus salta tor (Linnaeus)
A rgyrosomus hololepidotus
(Lacepede)
Diplodus sargus Linnaeus
Lithognathus aureti Smith
Lithognathus Iithognathus
(Cuvier in C & V)
Thyrsites alUn Euphrasen
Mugil cephalus Linnaeus
Pelagic, rather rare in Sand vis
Common in midwater
Abundant over sand banks
Abundant over banks and midwater
Only found once (Penrith 1977)
Pelagic, only young found
Rare in main lagoon, abundant adults and
juveniles found in pools and galleys
RareLiza Tricuspidens
(Smith)
Liza richardsoni A. Smith Large schools in main lagoon,
juveniles in shallows
Common in shallow areas. Important food
of predators
Channels of N. mud flats, between Perna.
wreck site
Common at wreck site, and Perna
Rocks and dredged at Perna
Juveniles very common at times
Common in mud banks
Hepset ia breviceps
(Cuvier in C & V)
Gobius nudiceps
Cuvier in C & V
alel/nius cornutus Linnaeus
Clinus superciliosus Linnaeus
Trigata sp.
Ophisurus serpens Linnaeus
Arctocephalus pusillus
(Schreber)
? Cephalorhynchus heavisidei
(Gray)
Europe to South Africa.
very rare on S.W.A. coast
There is confusion over the name of this
species.japollicus. capel/sis, trachrus
have all been used.
Cosmopolitan (missing inshore on W. coast)
Congo to Mocambique
Mediterranean to W. Indian Ocean
Cape Frio to Liideritz
Sandvis to S. Mocambique
Circumglobal in S. temperate waters
Circum-Tropical
Sandvis to Natal. Possibly
a synonyn of L. aurata Risso
S. Angola to South Cape
Cape Cross to Natal
Rocky Point to Kei River