Port Stanvac Jetty as significant marine habitat
Whom it may Concern
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It is likely that Port Stanvac jetty functions as a very significant artificial reef habitat in Gulf St Vincent, and available evidence indicates that the jetty supports species of conservation concern, including Leafy Seadragon, which is fully protected under South Australian legislation. Divers in SA and across southern Australia would like this marine environmental asset to be retained, possibly in a partly dismantled state, so that the site may be used for diving and dive tourism, by insured individuals, dive clubs and dive businesses. The jetty would also be very useful as a long term marine monitoring site, given its close proximity to the new desalination plant, and its previous use as a tidal monitoring station of regional significance.
We would recommend removal of some inshore surface structures (to prevent illegal fishing access from shore), but retention of offshore jetty surface structure as part of the reef habitat. If all of the overlying structures are taken away, habitat that has developed during the past 40+ years will be altered (and therefore community composition of marine fauna will change, due to increased light penetration, coupled with the likely change in local water circulation patterns). We also recommend retention of all subtidal structures, particularly the jetty piles, due to their role as reef habitat.
With regards to the option of retaining the jetty as an artificial reef and monitoring site, we would like to draw your attention to 13 points of justification, provided below. We are aware of the current maintenance and safety issues, but consider that this proposal may enable those obstacles to be surmounted.
Thanking you for your time, and hoping to hear from you soon.
from the following individuals:
J. Baker, Marine Ecologist
Dr S. Shepherd AO, Marine Biologist and Ecologist
S. Reynolds, SCUBA Divers Federation of South Australia
N. Skinner, Marine Life Society of South Australia
P. Mercurio, Environmental Chemist and Marine Photographer
M. Ludgate, Marine Cinematographer
P. Macdonald, Marine Photographer
J. Lewis, Marine Photographer
A. Brown, Diver and Marine Researcher
H. Crawford, Artist and Marine Photographer
J. Brook, Marine Consultant and Diver
C. Hall, Diver and Marine Photographer
and from the following associations:
Marine Life Society of South Australia
Flinders University Underwater Club
-The Leafy Seadragon Phycodurus eques and Weedy Seadragon Phyllopteryx taeniolatus occur in the vicinity of the jetty. Leafy seadragon has been recorded by video under the jetty, and weedy seadragon has been recorded by government survey about 800m west of the jetty, swimming along a pipe associated with the desalination plant. Leafy Seadragon is formally protected in SA waters under the Fisheries Management Act 2007. Both seadragons are nationally listed species, under the Environment Protection and Biodiversity Conservation Act 1999. It is of concern to dive groups and conservationists in SA that habitat for these species could willingly be destroyed.
-The Port Stanvac "dump", a dive site 300m north of the jetty, supports Blue Devilfish , Long-snouted Boarfish, and seadragons, according to recreational dive records, and Reef Watch data. All are species of conservation concern in South Australia, and listed in Conservation Council of South Australia's "In Peril" species list. The Stanvac "dump" is where surplus equipment (reportedly trucks, pontoons, barges, kilometres of cable) from the oil refinery was dumped into the sea, and has now formed an artificial reef. It is very likely that the artificial reef habitat of the Port Stanvac jetty also supports strongly site-associated species such as devilfish and boarfish, and other long-lived reef species of conservation concern. Surveys undertaken at other similar jetties in Gulf St Vincent and surrounds have shown such structures to provide habitat for boarfishes (e.g. Baker et al. 2008, 2009).
-Surveys at Rapid Bay jetty have shown that long jetties which support a variety of micro-habitats in both shallow and deeper water, have high species richness and diversity in fishes (Baker et al. 2008 Appendix 2; S. Shepherd, pers. comm.). Given the length and position of Port Stanvac jetty, it is quite likely that this jetty is similarly rich in fish species, particularly reef fishes, and a thorough survey of the jetty fauna is long overdue.
-Hard structures (such as Port Stanvac Jetty) in the mainly soft-bottom surrounds of the metropolitan waters of Gulf St Vincent (GSV) are ecologically important, as the few patch reefs and other jetties and artificial reefs in the area show.
-An underwater video made several years ago showed that the jetty piles support dense and colourful assemblages of marine invertebrates. Given the lack of disturbance in the area (other than previous periodic oil spills, and a sand dredging episode during the 1990s), it is possible that rare invertebrates also occur in both the intertidal and shallow subtidal area. During the mid- 2000s, an intertidal survey by Flinders University marine researchers on the intertidal reef directly south of Port Stanvac, showed the area to be species-rich, and supporting various invertebrate species that are no longer found in other parts of the metropolitan area.
-Given the length and depth of Port Stanvac jetty, and reduced light penetration due to the structure overlying the jetty piles, it is probable that the jetty provides habitat for deeper water fishes and invertebrates, and rare benthic species that exist in low light conditions. A number of SA's benthic reef fishes are rare, and known from very few records (Baker et al. 2008, 2009).
-Illegal fishing that has occurred in recent years at Port Stanvac jetty (e.g. see http://www.strikehook.com/forum/74-pirsa-fisheries/149812-stanvac-jetty?limit=15&start=15) indicates that the jetty support a large number of fish, including large individuals of fish species that are fully fished in South Australian waters, such as King George whiting, and Pink Snapper.
-Given that the jetty has been protected from recreational fishing for at least 40 years, in that time it would have developed as a significant refuge for reef fishes, and other fishes associated with vertical structure. Some of the more mobile fishes may periodically disperse away from the jetty, which would benefit recreational fishing in the eastern Gulf St Vincent region. Almost all jetties in Gulf St Vincent are open to recreational fishing, but given the significant role of Port Stanvac as a de facto marine refuge, this jetty should not be fished.
-Long jetties that provide significant habitat for both shallow and deeper water fishes, as well as numerous invertebrates that are associated with the jetty piles and material under the jetty, are important for diving. In this regard, the Port Stanvac jetty may be similar to the old Rapid Bay jetty, which has environmental, social and economic value (e.g. Davidson and Brook, 2006).
-Port Stanvac jetty could become a significant dive site. Given the currents and depth, access should be limited to insured divers, dive groups and dive businesses only, similar to the arrangement for diving the Hobart wreck off Wirrina. In this way, liability issues could be addressed, safety could be ensured, and there could be flow-on economic benefits for South Australia, due to dive tourism.
-The jetty would be a very useful long-term case study and monitoring site, for the possible changes that may occur to nearshore habitats and biota in mid-eastern Gulf St Vincent, following the development and operation of the desalination plant. This jetty could be a valuable monitoring site, using scientifically valid and internationally recognised Reef Life Survey methods. A baseline survey would be critical to determine the current composition and "health" of the marine life in the area prior to full operation of the desalination plant.
-There may be justification for declaring Port Stanvac jetty as an Aquatic Reserve, under the Fisheries Management Act 2007, particularly due to its role as a fish refuge, and as a habitat for protected species such as seadragons. An alternative option would be to declare the area as a Special Purpose Zone, or a Sanctuary Zone, under the Marine Parks Act. Irrespective of which piece of legislation is used, formal protection of the jetty is warranted.
-The end of the jetty has been a significant long-term weather and sea condition monitoring site for the Bureau of Meteorology, and this role could continue if the offshore jetty structures were retained. The Bureau of Meteorology has used the jetty to monitor tidal changes. Highly sensitive and sophisticated instruments have been used to monitor fluctuations in the tidal cycle and assess changes in sea level. This is important in verifying the impact of climate change on Adelaide's metropolitan coastline. The instruments were specifically installed at Port Stanvac because of the location in GSV; access to deep water on a solid structure; power availability and security (limited access by public). It has been reported that there is no other site in GSV that can support this type of equipment. The data collected have been utilised by State and Federal authorities, oceanographers, universities and private industry.
Baker, J.L., Shepherd, S.A, Brown, A., Muirhead, D., Crawford, H. and Lewis, J. (2008) Uncommon and cryptic reef fishes: results of pilot surveys along Fleurieu Peninsula, southern Yorke Peninsula and north-eastern Kangaroo Island. Report for South Australian Government's Wildlife Conservation Fund Project No. WCF 3718, June 2008.
Baker, J.L., Shepherd, S.A, Brown, A., Crawford, H. and Muirhead, D. (2008) Uncommon and cryptic reef fishes: results of pilot surveys along Fleurieu Peninsula. Report for Adelaide and Mt Lofty Ranges Natural Resources Management Board, South Australia. June 2008.
Baker, J.L., Shepherd, S.A, Crawford, H., Brown, A., Smith, K., Lewis, J. and Hall, C (2009) Surveys of uncommon / rare and site-associated reef fishes in South Australia. Report to Commonwealth Department of the Environment, Water, Heritage and the Arts, Envirofund Project 63120, October 2009.
Davidson, K. and Brook, J. (2006) Rapid Bay Jetty Closure: its triple bottom line impact to the Southern Fleurieu region. Report.