Lynnath Beckley

Recent major coastal disasters in the Asia-Pacific region have resulted in a massive loss of life and high societal costs. Unbridled development, growing coastal populations and injudicious land planning amplifies the predicted disaster risk due to climate change and extreme weather events. As it typifies expanding coastal development in areas prone to extreme weather events, the town of Exmouth (NW Australia) was used to investigate economic strategies for coastal risk mitigation. Recent marina development, with a loss of disaster mitigating ecosystem functions, has increased risk to previously unaffected areas. The extent to which risk perceptions of cyclonic storm-surge inundation and flooding influenced the price buyers paid for residential property in Exmouth over the period 1988–2013 was examined using a Hedonic Price Model. The analysis indicated that prices did not reflect the real societal cost of risk. Due to the absence of a monetary signal, such as higher insurance premiums, buyers tended to be risk insensitive and give greater weight to coastal amenity. To internalize these costs, a mandatory private insurance scheme for high-risk properties, penalties for local councils undertaking unsustainable developments, and a hybrid economic instrument aimed at correcting the market failure in coastal land, is proposed.

The South African coastline stretches from the mouth of the Orange River in the northwest to Kosi Bay in the northeast, a distance of some 3000 km. It covers a wide range of habitats from kelp beds to mangrove forests and coral reefs. The Benguela ecosystem on the west coast is characterised by upwelling and extends from Cape Point northwards, constituting the Namaqua biogeographic province. The warm temperate Agulhas biogeographic province is found on the south coast from Cape Point to East London and the Natal biogeographic province along the sub-tropical east coast. Marine biodiversity in south Africa is particularly high as a result of this environmental variability. Commercial, recreational and subsistence fisheries are discussed, many of which are harvested sustainably because of conservation legislation instituted by management agencies. There is no room for complacency, however, as there has been a serious depletion in some instances. Demographic pressures on the estuarine and coastal environments are cause for concern as well as the popular misconception of the sea providing an endless supply of food and as a repository for unlimited waste.

The dominant large-scale oceanographic feature along the east coast of southern Africa is the Agulhas Current Ecosystem, a western boundary current that forms part of the anticyclonic Indian Ocean gyre. The average course of the core of the current, which flows southward at speeds greater than 1 m/sec, follows the edge of the continental shelf, moving further from the coast as the shelf widens to form the extensive Agulhas Bank off the southern tip of Africa. Several studies have suggested that the Agulhas Current Ecosystem is responsible for the dispersal of the early life history stages of various fish species, and to test this hypothesis, three cruises were conducted in the southwest Indian Ocean during 1990 and 1991. Spatial and temporal oceanographic features of the region are presented and correlated with composition and abundance of the ichthyoplankton assemblages. In general, concentration of larvae decreased offshore, and there were marked differences in ichthyoplankton composition between stations on the continental shelf and offshore in the Agulhas Current Ecosystem. Larvae of clupeoids, myctophids, and some economically important perciform families are considered, and their observed distribution patterns related to possible dispersal mechanisms.

The dominant large-scale oceanographic feature along the east coast of southern Africa is the Agulhas Current Ecosystem, a western boundary current that forms part of the anticyclonic Indian Ocean gyre. The average course of the core of the current, which flows southwestward at speeds greater than 1 ms super(-1), follows the edge of the continental shelf, moving further from the coast as the shelf widens to form the extensive Agulhas Bank off the southern tip of Africa. Several studies have suggested that the Agulhas Current Ecosystem is responsible for the dispersal of the early life history stages of various fish species, and to test this hypothesis three extensive cruises were conducted in the southwest Indian Ocean during 1990/91. Spatial and temporal oceanographic features of the region are presented and correlated with composition and abundance of the ichthyoplankton assemblage. In general, concentration of larvae decreased offshore and there were marked differences in ichthyoplankton composition between stations on the continental shelf and offshore in the Agulhas Current Ecosystem. Larvae of clupeoids, myctophids, and some economically important perciform families are considered, and their observed distribution patterns are related to possible dispersal mechanisms.

Biological studies on several linefish species have revealed annual northward spawning migrations of adult fish from Cape to Natal waters. Juveniles of these species are encountered in inshore nursery areas in the Cape and in several papers spanning nearly two decades it has been suggested that the Agulhas Current is the mechanism responsible for the southward dispersal of the early life history stages of these species. In 1990 a SEFREF funded project commenced to study the ichthyoplankton along the east coast with the objective of testing the hypothesis that linefish larvae drift south in the Agulhas Current.