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
2001), the biota of hard grounds are known to be particularly vulnerable to the physical
disturbance associated with trawling (Turner et al. 1999). Typically trawling on and around hard
grounds and seamounts (such as that associated with the orange roughy fishery) causes damage
to the structure-forming biota associated with these habitats (Ragnarsson and Steingrimsson
2003). This in turn causes reduced habitat complexity, affecting community structure and
diversity (Kaiser et al. 2000). No studies specific to the impacts of trawling on Namibian hard
grounds have been conducted.
3.3 MID-WATER TRAWL FISHERY
The Cape horse mackerel has the highest volume and catch of all Namibian fish stocks; however
by economic value it is the second highest contributor to the fishing industry behind the fishery
for hake. Horse mackerel are either converted to fishmeal or sold as frozen, whole product.
Landings for the year 2006 were valued at N$800 million (MFMR unpublished data in Kirchner et
al. 2010). The stock is caught by the mid-water trawl fishery (targeting adult horse mackerel) and
pelagic purse-seine fishery (smaller quantities of juvenile horse mackerel). Maximum historical
catches were reported during the 1980s but catch rates have since declined with an average of
252,680 tonnes between 1990- 2008 (see Figure 10 for annual set TACs and catches). TACs have
decreased from 360,000 to 230,000 tonnes following a decline in estimated stock biomass in
recent years.
Figure 10. Catches (mid water and purse seine) and TACs set for the Namibian stock of Cape horse mackerel
from 1961 to 2009 (Kirchner et al. 2010)
Final Report
Namibian Marine Phosphate (Pty) Ltd.
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