Coasts & Estuaries - City of Port Adelaide Enfield - SA.Gov.au

Coast & EstuariesFisheriesThe fisheries of the Gulf St Vincent are an important ecological resource. The commercial andrecreational fishing industries have economic importance to the State. The over exploitation (overfishing) of these resources can have a significant impact on the ecology of our marine life, and theviability of industries. In South Australia the management of fisheries is overseen by the StateGovernment (PIRSA). The Barker Inlet St Kilda Aquatic Reserve and St Kilda/Chapman CreekAquatic Reserve form part of this fisheries management system.The Department of Environment and Heritage expresses concerns regarding the sustainability ofNorthern Zone rock lobster and snapper in Gulf St Vincent.The impacts of recreational fishing are noted. Recreational fishing is responsible for a greaterproportion of the fish catch for certain species (principally snapper and King George whiting) than thecommercial sector, however there are not the same levels of control in relation to total annual catchlevels.There are environmental, social and economic effects of over-exploiting fisheries. Effectivemanagement is required to ensure commercial and recreational fisheries remain sustainable and thatmarine biodiversity is not adversely affected by over fishing or damaging habitats through fishingpractices (DEH, 2006).Port Adelaide was subject to an ‘Inventory of Important Coastal Fisheries Habitats in South Australia’.Threats to fisheries habitats were identified within the study. Some of these include: establishment ofexotic pest species such as the Sabellid fanworm north of Outer Harbor and Caulerpa taxifolia inWest lakes and upper Port Adelaide River; increased nutrients caused by the Bolivar SewageTreatment outfall; altered patterns of water and sediment movement caused by the location of theOuter Harbor breakwaters; physical disturbance caused by human trampling; bait digging and off roadvehicle use; increased turbidity and sedimentation caused by intermittent dredging operations atOuter Harbor and in Port Adelaide River; increased heavy metals caused by atmospheric fall out andstormwater runoff of industrial effluent in the region; and thermal pollution from the Torrens Islandpower station (Bryars 2003).Coastal DevelopmentPressures of urbanisation and developments associated with coastal tourism significantly impacts onthe coastal zone. Development in close proximity to the beachfront damages the natural dunesystem. The clearing of dune vegetation and modification to the shore line disrupts the natural coastalenvirons.Urban development resulted in accelerated erosion of parts of the foreshore. Undisturbed dunes actas physical barriers that absorb wave energy and thereby protect inland areas from waves and tides.Dunes also store large quantities of sand that replenish beaches affected by wave and storm damageand play an important ecological role by supporting a diverse range of flora and fauna (Petherick2005).Coastal development has caused large quantities of sand to be ‘locked up’ or removed from thebeach system. Many of Adelaide’s coastal suburbs were built on an extensive system of coastaldunes, land was reclaimed along the Lefevre Peninsula to establish the suburb of North Haven.If development on the coast was restricted, the natural recession of the coast would have beenallowed with the coastline alignment progressively adjusting inland at southern beaches inaccordance with natural northward littoral drift of sand.157