State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
the construction of an offshore structure, such as a groyne, to change the wave and current
dynamics suspected to be underlying cause of the erosion. A positive Record of Decision (ROD) for
the construction of the gabion wall was issued by the Department of Environmental Affairs and
Development Planning, Western Cape (DEADP), and construction was begun during 2010 and is
ongoing (J. Kotze – Langebaan Ratepayers Association, pers. comm. 2011).
4.3.4 Shipping, ballast water discharges, and oil spills
4.3.4.1 Shipping and ballast water
Shipping traffic comes with a number of attendant risks, especially in a port environment,
where the risks of collisions and breakdowns increase owing to the fact that shipping traffic becomes
concentrated, vessels are required to perform difficult manoeuvres, and are required to discharge or
take up ballast water in lieu of cargo that has been loaded or unloaded. Saldanha Bay is home to the
Port of Saldanha, which is one of the largest ports in South Africa receiving over 400 ships per
annum. The Port comprises of an Iron export terminal for export of iron ore, an oil terminal for
import of crude oil, a multi-purpose terminal dedicated mostly for export of lead, copper and zinc
concentrates, and the Sea Harvest/Cold Store terminal that is dedicated to frozen fish products
(Figure 4.1). There are also facilities for small vessel within the Port of Saldanha including the
Government jetty used mostly by fishing vessels, the TNPA small boat harbour used mainly for the
berthing and maintenance of TNPA workboats and tugs, and the Mossgas quay. Discharge of ballast
by vessels visiting the iron ore terminal in particular poses a significant risk to the health of Saldanha
Bay and Langebaan Lagoon.
Ships carrying ballast water has been recorded since the late nineteenth century and by the
1950’s had completely phased out the older practice of carrying dry ballast. Ballast is essential for
the efficient handling and stability of ships during ocean crossings and when entering a port. Ballast
water is either freshwater or seawater taken up from ports of departure and discharged on arrival
where new water can be taken on, depending on the cargo load. The conversion to ballast water set
off a new wave of marine invasions, as species with a larval or planktonic phase in their life cycle
where now able to be transported long distances between ports onboard ships . Furthermore,
because ballast water is usually loaded in shallow and often turbid port areas, sediment is also
loaded along with the water and this can support a host of infaunal species (Hewitt et al 2009). The
global nature of the shipping industry makes it inevitable that many ships must load ballast water in
one area and discharge it in another, which has an increasing potential to transport non-indigenous
species to new areas. It has been estimated that major cargo vessels annually transport nearly 10
billion tonnes of ballast water worldwide, indicating the global dimension of the problem (Gollasch
et al. 2002). It is estimated that on average, 3,000-4,000 species are transported between
continents by ships each day (Carlton and Geller 1993). Once released into ports, these nonindigenous
species have the potential to establish themselves in a new environment which is
potentially free of predators, parasites and diseases, and thereby outcompete and impact on native
species and ecosystem functions, fishing and aquaculture industries, as well as public health
(Gollasch et al. 2002). Invasive species include planktonic dinoflagellates and copepods, nektonic
Scyphozoa, Ctenophora, Mysidacea, benthos such as annelid oligochaeta and polychaeta, crustacean
brachyura and molluscan bivalves, and fish (Carlton and Geller 1993). Carlton and Geller (1993)
record 45 'invasions' attributable to ballast water discharges in various coastal states around the
world. In view of the recorded negative effects of alien species transfers, the International Maritime
Organisation (IMO) considers the introduction of harmful aquatic organisms and pathogens to new
environments via ships ballast water as one of the four greatest threats to the world’s oceans (Awad
et al. 2003).
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 61