Fisheries - Enviro Dynamics Namibia

F I S H E R I E S , M A M M A L S A N D S E A B I R D S S P E C I A L I S T S T U D Y
1999). No information exists in the published literature regarding spawning and recruitment of
west coast sole along the Namibian coast.
2.2.4 Orange roughy
Orange roughy Hoplostethus atlanticus is a deep sea species occurring at depths of 400 – 1400 m
(Branch 2001). These fish are unusual in that they are very long-lived (> 100 years) and slow
growing (reaching sexual maturity at around 25 years), have low fecundity and show low natural
mortality (Boyer and Hampton 2001a, Boyer et al. 2001b, Branch 2001). Off Namibia this species
has a restricted spawning period of less than a month in late July, when spawning takes place in
dense aggregations close to the bottom in small areas typically between 10 and 100 km 2 in extent
(Boyer and Hampton 2001b).
2.3 OTHER FISH SPECIES
2.3.1 West coast steenbras
Two stocks of west coast steenbras Lithognathus aureti occur in Namibian waters, a southern
population around Meob Bay and a northern population in central and northern Namibia
(Holtzhausen and Kirchner 2001a). The southern population falls within the restricted area of the
Namib-Naukluft Park. No spawning migration is known for this species, although males of the
northern population appear to disperse south in search of gravid females (Holtzhausen et al.
2001). The diet of this species is focused on the mussels Choromytilus meridionalus and Perna
perna (Holtzhausen and Kirchner 2001b).
2.3.2 Silver kob
Silver kob Argyrosomus inodorus occurs along the entire length of the Namibian coast but are
most abundant from Meob Bay to Cape Frio (Kirchner and Voges 1999). Namibian stocks are
distinct from those occurring off South Africa (Van der Bank and Kirchner 1997). Spawning adults
move southwards from the northern end of their distributional range in early summer. Spawning
occurs at Meob Bay and Sandwich Harbour (Holtzhausen et al. 2001). From here larvae drift
northward to the nursery area between Sandwich Harbour and the Ugab River mouth. Two years
after spawning juveniles reach the area north of the Ugab River. It is to this same area that adults
return after spawning (Kirchner and Holtzhausen 2001). Note that there is a concern that the
discharge pipeline from the dredging operations (which is 2 m in diameter and will be laid on the
sea floor i.e. not buried, for the first two years of operation) will obstruct kob on their way to and
from the spawning ground at Sandwich Harbour however this has been considered and referred
to in Pulfrich and Steve Lamberth terrestrial EIA report. In northern Namibia silver kob feed
mainly on pelagic fish, shrimps and squid, whereas in the central and southern Namibia shrimps
dominate the diet of these fish (Kirchner 1999).
2.3.3 Bearded goby
The bearded goby Sufflogobius bibarbatus occurs from the Kunene River to the east coast of
South Africa (Cruickshank et al. 1980). Juveniles of this species usually inhabit inshore waters
shallower than 200m, with the greatest concentrations occurring within 10 km to 30 km of the
Final Report
Namibian Marine Phosphate (Pty) Ltd.
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