108
A.J. Underwood . M.G. Chapman
The commonly cited potential effects of the development and running of marinas
include
i. degradation of quality of water from pollutants and changes to natural patterns of
circulation (Baird et al. 1981; Turner et al. 1997),
ii. detrimental changes to the fauna and flora in habitats near marinas because of pollutants, changes to water flow and shading (Iannuzzi et al. 1996),
iii. direct damage to sensitive habitats, such as seagrass beds by physical impacts of
anchors and chains (Walker et al. 1989), and
iv. direct toxicity to fauna by contaminants such as TBT (Waldock and Thain 1983; Gibbs
and Bryan 1994).
\ Nevertheless, despite such widespread and varied potential impacts, there are no
systematic data on the relative importance of the different effects of marinas and other
forms of mooring of recreational boats in urbanized areas of Australia, including
Port Jackson (Sydney) and the other estuaries. This is the case, despite the fact that there
are approximately 40 marinas and more than 10 000 mooring berths (in marinas and
on floating buoys) in the four estuaries around Sydney. In addition, managerial decisions about the development and expansion of marinas and other mooring structures,
including decisions to replace jetties with floating pontoons, are being made on an
ongoing basis and changes to marinas are subject to varied regulations because of
potential environmental impacts. The results of such decisions are seldom examined
within a scientific framework to evaluate their relative usefulness.
Because of a need to evaluate the relative effects of mooring in marinas or on mooring
buoys in order to improve management of marinas and recreational boating facilities,
in 1995 a collaborative research programme was developed between the Institute of
Marine Ecology (University of Sydney), the Boating Industry Association of Australia
and the Marinas Association of New South Wales. The research was aimed to identify
effects of marinas and mooring buoys on marine fauna and flora in the vicinity. This
study was supplemented by a study of organisms on rocky reefs near and away from
marinas (Glasby 1997a). This information can be used by the recreational boating industry to improve management of these facilities, thereby changing management from
a reactive response (to perceived or real impacts on a case-by-case basis) to a proactive
response (developing general practices to improve their environmental record).
The fauna examined included invertebrates living in the sediments, on nearby rocky
reefs, in seagrass beds, in the holdfasts and on the blades of kelps growing on these
reefs and on the blades of the seagrasses. Such assemblages of invertebrates are diverse
and numerous and their responses to different types of disturbances (e.g. chemical
contamination, turbidity, changes to flow of water) are documented. In addition, as
adults they are generally sessile or do not disperse very far and any differences in their
abundances or diversity are likely to be strongly influenced by local conditions. Any
widespread and general effects of marinas or boat moorings should, therefore, be found
in a number of different assemblage~. Although fish accumulate around structures
(Picken and McIntyre 1989), they were not examined in this project because they can
respond to influences away from the study sites and therefore any differences identified from place to place cannot easily be attributed to conditions in those places. In
addition to the fauna, the areal extent of the seagrasses Posidonia australis and Zostera
A.J. Underwood . M.G. Chapman
The commonly cited potential effects of the development and running of marinas
include
i. degradation of quality of water from pollutants and changes to natural patterns of
circulation (Baird et al. 1981; Turner et al. 1997),
ii. detrimental changes to the fauna and flora in habitats near marinas because of pollutants, changes to water flow and shading (Iannuzzi et al. 1996),
iii. direct damage to sensitive habitats, such as seagrass beds by physical impacts of
anchors and chains (Walker et al. 1989), and
iv. direct toxicity to fauna by contaminants such as TBT (Waldock and Thain 1983; Gibbs
and Bryan 1994).
\ Nevertheless, despite such widespread and varied potential impacts, there are no
systematic data on the relative importance of the different effects of marinas and other
forms of mooring of recreational boats in urbanized areas of Australia, including
Port Jackson (Sydney) and the other estuaries. This is the case, despite the fact that there
are approximately 40 marinas and more than 10 000 mooring berths (in marinas and
on floating buoys) in the four estuaries around Sydney. In addition, managerial decisions about the development and expansion of marinas and other mooring structures,
including decisions to replace jetties with floating pontoons, are being made on an
ongoing basis and changes to marinas are subject to varied regulations because of
potential environmental impacts. The results of such decisions are seldom examined
within a scientific framework to evaluate their relative usefulness.
Because of a need to evaluate the relative effects of mooring in marinas or on mooring
buoys in order to improve management of marinas and recreational boating facilities,
in 1995 a collaborative research programme was developed between the Institute of
Marine Ecology (University of Sydney), the Boating Industry Association of Australia
and the Marinas Association of New South Wales. The research was aimed to identify
effects of marinas and mooring buoys on marine fauna and flora in the vicinity. This
study was supplemented by a study of organisms on rocky reefs near and away from
marinas (Glasby 1997a). This information can be used by the recreational boating industry to improve management of these facilities, thereby changing management from
a reactive response (to perceived or real impacts on a case-by-case basis) to a proactive
response (developing general practices to improve their environmental record).
The fauna examined included invertebrates living in the sediments, on nearby rocky
reefs, in seagrass beds, in the holdfasts and on the blades of kelps growing on these
reefs and on the blades of the seagrasses. Such assemblages of invertebrates are diverse
and numerous and their responses to different types of disturbances (e.g. chemical
contamination, turbidity, changes to flow of water) are documented. In addition, as
adults they are generally sessile or do not disperse very far and any differences in their
abundances or diversity are likely to be strongly influenced by local conditions. Any
widespread and general effects of marinas or boat moorings should, therefore, be found
in a number of different assemblage~. Although fish accumulate around structures
(Picken and McIntyre 1989), they were not examined in this project because they can
respond to influences away from the study sites and therefore any differences identified from place to place cannot easily be attributed to conditions in those places. In
addition to the fauna, the areal extent of the seagrasses Posidonia australis and Zostera