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The Sydney Morning Herald smh.com.au TUESDAY, DECEMBER 4, 2012 11
EDITORIAL FEATURE IN ASSOCIATION WITH THE SYDNEY INSTITUTE OF MARINE SCIENCELIVING HARBOUR: DYNAMIC SCIENCE
■ Editor Bellinda Kontominas, [email protected] ■ Advertising Elisha Clothier, 9282 2373, [email protected] ■ Readerlink 9282 1569, [email protected]
Ecosystems worth saving
Fighting back ... (clockwise from above) a researcher investigates seagrass beds in Sydney Harbour; seagrass and moorings in Shoal Bay; Desmond Maslen. Photo: Rob Carraro
An innovativemooring scheme aimsto minimise damageto seagrass beds,writes Guy Wilkinson.
WHEN Desmond Maslen wasworking as a mooring contractorin Port Stephens, he saw firsthandthe devastating effect the existingswing-mooring systems werehaving on seagrass beds.
His love of the environment,coupled with a strongbackground in engineering,prompted him to work on a newmooring system that wouldsignificantly reducedestruction of marine life andimprove the sustainability ofrecreational boating in andaround Sydney.
After two years ofdevelopment – during whichtime he had to ensure the systemcould withstand adverseweather conditions – Maslenreleased his new invention,known as SeagrassFriendly Mooring.
The system is designed with asingle point screwed in to placethe mooring post as the anchorpoint and uses a set of loadspreaders to help reduce theimpact on the seabed.
‘‘It offers a natural, shelteredenvironment for marine life toeat, live and grow . . . while stillmaintaining a secure swingmooring for boats,’’ Maslen says.
‘‘On one occasion, whilerowing out to my own mooredboat with my family, we saw aturtle that had settled under theshock absorber of a SeagrassFriendly Mooring. It was eatingthe regrown seagrass.
‘‘For me, this was one of themost defining moments of themooring’s worth.’’
As well as winning the ABC NewInventors program, Maslen’smooring system has beeninstalled at sites around ManlyCove and is now being evaluatedby scientists at the University ofTechnology, Sydney.
Under a government-funded,four-year study at Manly Cove,experienced volunteers fromEco Divers are using underwatercameras to record the cover andlength of seagrass in areasaround the mooring whereseagrass had been scoured bythe old swing system.
As well as the SeagrassFriendly Mooring, informationis also being collected aroundswing moorings and in seagrassbeds with no moorings, toensure the data is an accuratereflection of the impact ofMaslen’s invention.
‘‘Seagrass beds areproductive, shallow-waterecosystems that provide a
habitat for a large number ofspecies and serve as a criticalnursery habitat for many speciesthat are important forcommercial and recreationalfishing activities,’’ says aprofessor from the Universityof Technology’s school ofthe environment, WilliamGladstone. He says seagrassbeds have declined in health andnumbers in NSW because ofincreased turbidity, erosionfrom dredging, siltation,nutrient pollution, sea-urchingrazing, prawn trawling and thewidespread construction ofmoorings and jetties.
‘‘Moorings are a source ofpressure on seagrass beds, andthe loss of seagrass aroundswing moorings is likely tocontribute, along with otherpressures, to declines inecosystem health and negativeimpacts on the species andhuman uses dependent onseagrass,’’ Gladstone says.
‘‘This study is testingwhether the Seagrass Friendly
Moorings are living up toexpectations, and it’s a criticalpart of the evidence needed formanaging the human uses ofSydney Harbour so they areecologically sustainable.’’
Maslen says his projecthas estimated economic
benefits of $11.4 million a year,based on 15,000 registeredmoorings in NSW and thepotential increase in marinespecies to the fishing industry.
He is currently involved in aproject with SEQ Catchments toreplace 100 moorings in
Moreton Bay, off theQueensland coast.
He is also installing new, andservicing existing, SeagrassFriendly Moorings in NSW andhopes a shift in policy willensure the environmentallyconscious system becomes
mandatory in sensitive areas.Maslen has plans to expand thebusiness into a franchisesystem, which will enablesubcontractors to be fullytrained and equipped to installand service his inventionthroughout Australia.
Mighty creatures best viewed from a distance
Spectacular ... a whale breaches in Sydney Harbour. Photo: Emma Birdsey
With more whales coming into the harbour, boaties must steer clear while admiring the majestic mammals, writes Keeli Cambourne.
THEY call the east coast ofAustralia the ‘‘HumpbackHighway’’ and Sydney Harbouris a rest stop along the way formany of the 14,000-16,000humpback whales that make themigration each year.
As their population grows,humpbacks, and more recentlysouthern right whales, areincreasingly stopping to rest inthe harbour’s calmer waters.Although their presence creates awonderful show, it can also causechaos for the many who use thewaters in and around the basin.
An expert at the marineecology faculty at Macquarie
University, Professor RobertHarcourt, runs a marinemammal research groupassociated with the SydneyInstitute of Marine Science,looking at how tourism affectshumpbacks in Sydney andwhether the use of alarms couldprevent whales becomingentangled in fishing nets.
Harcourt says federal lawsrequire that no more than threeboats are allowed within a300-metre radius of a whale, orfurther if a calf is present.
‘‘That is quite a large area andSydney Harbour is prettycrowded, so this is an ongoing and
growing issue, especially with thewhale population increasing at11 per cent per annum – as fast asit can grow,’’ he says.
Harcourt has been studyinghow whales respond to boatsand has found that if a vessel iswithin one kilometre of a whale,the animal’s behaviour changes.
‘‘In some other places thewhales dive, but in SydneyHarbour they spend a longertime on the surface,’’ he says.‘‘These are animals that havegone past boats throughout theirlife and even though tourism hasgrown, so has the numberof whales.
‘‘On their southerly migration,mothers and calves willoccasionally come over to lookat boats, and young males arevery curious about boats. Thischange of behaviour has beenobserved in other parts of theworld. Humpbacks are veryplayful and are great for tourism,and sometimes they come andsit around boats – even to liebetween pontoons.’’
Harcourt says this behaviourindicates tourism has no effecton the population growth ofwhales, but the industry mustuse best practice to ensure thisremains the case.
The manager of the marinefauna program for the NationalParks and Wildlife Service,Geoff Ross, says whales cominginto the harbour are ofteninspecting traditional haunts,which is typical behaviour offemales with calves.
‘‘The southern right whalescheck out bays and estuaries,educating the calf about where togo, how deep the water is, lookingfor protected waters for thewelfare of the calf, particularly ifthere are killer whales or greatwhite sharks around,’’ Ross says.
‘‘We have plans in place nowwhere we [the NPWS] move into
a patrol location to assess theanimal’s welfare and have aNPWS boat stay with the animaland notify all major users of theharbour . . . to warn skippersabout the location of the whale.’’
The manager of Sydney’s Bassand Flinders Cruises, Will Ford,says he has seen more whalescoming into the harbour andthat following the rules is part ofowning the business.
‘‘The drama comes withrecreational boaters on weekends.. . as they don’t know the rules [onexclusion zones] and can getcarried away, but most people arepretty good,’’ he says.
World first ... associate professor Emma Johnston, who leads the‘‘ground-breaking’’ Sydney Harbour Research Program.
Fish are jumping,but there’s a catchPollutants provide nutrients that help SydneyHarbour to thrive although too much can ruinthe delicate balance, writes Melinda Ham.
NOT getting enough nibbles onyour line at your favouritefishing spot?
Maybe Sydney Harbour wouldbe a better bet. Port Jackson isone of the most prolific estuariesin the state, surprising scientistsand outdoing Port Hacking insouthern Sydney, and thepristine marine parks of JervisBay and Batemans Bay, for thenumber of fish it produces,according to new research.
‘‘It’s actually a ground-breaking study,’’ says thedirector of the Sydney HarbourResearch Program at the SydneyInstitute of Marine Science(SIMS), associate professorEmma Johnston, who led theresearch team over three years.
‘‘There hasn’t been a study likethis worldwide; we’ve collectedlocal information that will have aglobal relevance.
‘‘It’s really nice that it’s not alldoom and gloom and negative;that the harbour is still aliveand thriving.’’
Using baited, underwatervideo cameras and thenreplaying the footage to countthe number of fish, Johnston andher team of marine scientistscalculated the volume of fish atvarious locations scatteredaround Port Hacking, Jervis Bay,Batemans Bay and SydneyHarbour. In addition, theynetted, weighed and thenreleased other fish.
‘‘We also looked at the numberof invertebrates living in thesediment and found that therewas actually more productivityin the whole food chain,’’ saysJohnston, who jointly won thisyear’s NSW Scientist of the Yearaward for excellence inbiological sciences.
While all the four study areashad the same variety of fish
species, Sydney Harbour cameout ahead of Port Hacking andthe marine parks, with thelargest number, especially ofpopular recreational fish such aspink snapper, silver trevally andyellowfin bream.
So why is Sydney Harbourflourishing? Historically, it’sbeen a naturally productive,well-flushed estuary and wasprobably one of the reasons forcolonial settlement, says asenior research scientist at NSWFisheries, Dr Melinda Coleman,who jointly led the team.
With more than 1 millionpeople now living around theharbour, this has furtheraffected the waterways. ‘‘Thereare lots of extra nutrientsrunning off into the harbourfrom fertiliser on lawns andstormwater,’’ she says. ‘‘Thismay feed the food web.’’
The harbour also has a lot ofman-made structures such asbreak walls and jetties, which area great place for invertebratesand fish to live.
But Johnston warns that weshouldn’t be complacent. ‘‘Weare walking a tightrope,’’ shesays. ‘‘There’s still the danger ofalgal blooms and red tides; wesaw that in the 1990s. Theharbour also has world-recordlevels of toxic contaminants inits sediment.’’
And what about eatingharbour fish? Although theresearch team tested fish tissuefor heavy metals such as lead,arsenic, copper and zinc, onlythose caught nearWoolloomooloo had unsafelevels for human consumption,Johnston says. But theydidn’t test for dioxins.Commercial fishing hasbeen banned in theharbour since 2006.
