44-661: Lake Awoonga was formed on the Boyne River by the dam located 30 km (19 mi) from Gladstone , in Central Queensland , Australia . It is approximately 30 minutes drive from Gladstone, via Benaraby . Lake Awoonga is the main water supply for the Gladstone region. Its recreation areas and recreational fishery are provided free to locals and tourists by the Gladstone Area Water Board. Originally built across
88-645: A large scale. Weirs are also believed to have blocked the migrations of spawning adults and juveniles, which are important to maintain populations over the lengths of rivers. Weirs also kill most drifting silver perch larvae that pass through them, if they are of an undershot design (which, unfortunately, most are). Recent studies that has proven more than 90% of silver perch passing through undershot weirs are killed. And without doubt, weirs trap drifting silver perch eggs (and larvae) as well, where they are either diverted down irrigation offtakes, resulting in eventual death, or sink into fine weir pool sediments and die. It
132-759: A mysterious, rapid and catastrophic decline. Silver perch have now declined close to the point of extinction in the wild. Based on simple catchment area estimates, the silver perch has disappeared from 87% of its former range. Only one sizeable, clearly viable and self-sustaining population now survives in their natural range, in the central reaches of the Murray River . For these reasons, the Australian federal government has listed wild silver perch as critically endangered under national environmental law. Silver perch are bred extensively in aquaculture but these domesticated strains and captive populations are of little use in ensuring
176-477: A new impact that is not understood on an already imperilled species, creating a narrowed window of time for breeding and recruitment (recalling females only reach sexual maturity at 5 years of age). The finding has sparked fresh concerns about their conservation in a heavily regulated river system and some changes in management. As recently as the 1970s, silver perch abounded in the entire Murray-Darling Basin, vast though it is. Since then, however, they have undergone
220-541: A preference for flowing water. Though nowadays found in the lowland reaches of the Murray-Darling system, they originally had a strong presence in the slope and upland reaches of many Murray-Darling rivers as well. In particular, they had a strong presence in upland reaches of the Murrumbidgee River and were originally found as far upstream as Cooma . As recently as the early 1980s, long summer migrations into
264-458: A quarry on the side of the dam wall. The embankment is over 650 metres (2,130 feet) in length and 54.4 metres (178 feet) in height, with a volume of approximately 2,000,000 cubic metres (71,000,000 cubic feet) of rock. This design of the current dam allows for further raising, if necessary, through the addition of gates to the top of the spillway. The maximum capacity of the present dam is 777,000 megalitres (2.05 × 10 US gallons). The second raising of
308-485: A total of over 2.9 million fish had been released into Lake Awoonga including 2.4 million barramundii , 470,000 sea mullet and 15,000 mangrove jack. These fish were bred at Gladstone Area Water Board's Fish Hatchery facility. The largest barramundi caught, as at November 2008, weighed in at a 36.5 kg (80.5 lbs). Lake Awoonga is one of the only dams in Australia to have been stocked with mangrove jack. Lake Awoonga
352-467: Is a basic camping facility around the southern side of Lake Awoonga, ten minutes from the townships of Many Peaks and Ubobo. Access is via a dirt road from the Gladstone to Monto Road which may become boggy in wet weather. There is no potable water at this site. The area inundated by the dam includes much of the Glengarry pastoral station, making it unviable as a pastoral property and so it was purchased by
396-568: Is competition for food between introduced carp and silver perch at larval, juvenile and adult stages. Competition at the larval stage is considered the most serious. Indeed, suspicions are mounting that introduced carp are having very large impacts on a number of native Murray-Darling fish species due to competition at the larval stage, and that these impacts have so far been underestimated. Exotic pathogens such as EHN virus and possibly similar viruses, introduced via importation of non-native fish, are now strongly suspected of playing pivotal role in
440-455: Is home to an array of small animals, several of which are of conservation significance including the grey-headed flying fox and the yellow-bellied glider . Aquatic vegetation maintains an array of small animals that support the fish, eels, turtles, platypus and birds. Other species of birds, reptiles, and native fauna including bandicoots , rufous bettongs , kangaroos , wallabies , greater gliders , and brushtail possums can be found around
484-647: Is located between the twin towns of Boyne Island and Tannum Sands . A bridge was built to cross the river joining the two towns in 1980. The river is dammed by the Awoonga Dam which is the major water source for the Gladstone region. The river has a catchment area of 2,496 square kilometres (964 sq mi) of which 49 square kilometres (19 sq mi) are riverine wetlands and 17 square kilometres (7 sq mi) are estuarine wetlands. The Queensland Department of Environment and Heritage Protection consider
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#1732883750639528-473: Is not clear if these results are simply the result of extreme blackwater fish kills in the Murray River between 2010 and 2012, the result of some other human/management impact, or a true expression of the species' biology. The latter is doubtful as extensive sampling of the same population in the 1990s found a normal age structure with fish up to 17 years of age. More concerning is the possibility this represents
572-541: Is not widely appreciated that silver perch eggs sink in still water; silver perch eggs are often inaccurately described as simply being pelagic, or "floating". The eggs may actually settle onto the substrate in the wild and should perhaps be considered benthic in many circumstances rather than pelagic. This may be a factor in their recent serious declines; silver perch may rely on their eggs settling onto clean, well oxygenated substrates of coarse sediments. In this era of flow regulation and flood curtailment by dams, which control
616-712: Is self-sustaining. The long established prohibition on fishing, the consequent absence of exotic fish and their diseases, and the pristine nature of the dam, including a largely undisturbed, thickly-forested sandstone-dominated catchment and an abundance of coarse rubble and gravel in many inshore areas, where fertilised eggs can settle and not be smothered by silt, are all likely contributors to this unique situation. Fishermen caught silver perch on unweighted baits such as worms and on small spinning-blade lures in rapids during migrations into upland rivers, as well as flowing and moving waters more generally. They were renowned for being very fast and strong fighting fish. The [fishing] rod
660-431: Is streamlined and laterally compressed, with a spiny dorsal fin of medium height, angular soft dorsal and anal fins and a forked tail. Large specimens become very deep bodied with a large hump behind the head. In terms of colouration, they are dark grey to silvery greyish-brown on the back, silver-grey on the sides, with darker scale margins giving a checkered pattern; the belly is whitish; the dorsal and caudal fins are dark,
704-717: Is … used amongst the bream [silver perch] which run up to six pounds, and fight every inch of their way from the time they are struck till they are safely landed. … It is as easy to land a fifteen pound cod as it is a five pound bream, as the latter is notoriously the hardest fighter in our rivers, only being even nearly approached by the catfish. Male silver perch reach sexual maturity at three years of age. Female silver perch reach sexual maturity at five years of age. Silver perch spawn in late spring and early summer. Originally water temperatures of close to 24 degrees Celsius were considered necessary for spawning to occur but as with all Murray-Darling fish species it has become apparent that
748-402: The Boyne River south west of Gladstone in the early 1950s as a 12m high mass concrete dam, it was raised by 6m shortly after. In the 1980s it was raised again, now as a rockfill structure with a concrete upstream face slab to a full supply level of 30m AHD. The dam was raised for a third time in 2002 to its current full supply level of 40m AHD. The embankment was formed from rock excavated from
792-557: The Murray-Darling river system in south-eastern Australia . The silver perch's scientific name comes from an aboriginal name for the species – bidyan – recorded by Major Mitchell on the Barwon River on his 1832 expedition. (Mitchell's original scientific name for the species was Cernua Bidyana .) Silver perch are not a "true" perch of the genus Perca , but are instead a member of Terapontidae or 'grunter' family. They are
836-427: The spangled perch ( Leiopotherapon unicolor ), does occur sporadically in the northern Murray-Darling Basin. Common names for Bidyanus bidyanus include silver perch, black or silver bream and the aboriginal names 'bidyan' (northern NSW) and 'tcheri/tcheeri' (South Australia). The silver perch is a large grunter with a small head, small eyes, a small mouth at the end of a pointed 'beak-like' snout. The species
880-573: The "required" spawning temperature is flexible and that they can and do spawn at lower temperatures. Researchers in the Barmah Forest region of the Murray River have collected drifting fertilised silver perch eggs in water temperatures as low as 17.2 degrees and as high as 28.5 degrees C, between early November and mid-February. Eggs were consistently collected in water temperatures above 20 degrees. Silver perch are moderately fecund , with egg counts commonly around 200,000 to 300,000. Spawning occurs at
924-614: The Boyne River to be the southern habitat extent of the saltwater crocodile . However, crocodiles can occasionally be found as far south as the Mary River . The river was named in 1823 by John Oxley as it reminded him of the River Boyne in Ireland. Bidyanus bidyanus The silver perch ( Bidyanus bidyanus ) is a medium-sized freshwater fish of the family Terapontidae endemic to
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#1732883750639968-565: The Gladstone Area Water Board on 1 August 1979. It is expected when the dam is at its highest levels of inundation, the heritage-listed Glengarry Homestead will be on an island within the dam. Boyne River (Central Queensland) The Boyne River is a river in Central Queensland , Australia. The headwaters of the river rise in the Bobby Range, within the Great Dividing Range southwest of Miriam Vale . The river descends from
1012-628: The Lake Eyre system. A translocated and reproducing population of silver perch exists in Cataract Dam on the Hawkesbury-Nepean system. This population was established by NSW Fisheries translocations of juvenile fish from drying billabongs in the lower Murrumbidgee River in approximately 1915–17. The Cataract Dam population is unique in being the only population of silver perch in an artificial impoundment that regularly and successfully recruits and
1056-402: The agitation of the surface. Next moment the water all around and below the fish had assumed a whitish, opaque tinge, as though a bucket of milk had been thrown in; clearly caused by the extrusion of the milt of the male fish, and its contact with the colourless ova thrown out by the female fish. The operation was repeated five or six times at intervals of about 20 to 30 minutes. Soon after sundown
1100-482: The area. There are a number of declared alien plants and environmental weeds proliferating throughout the river system and the catchment including parthenium , salvinia , cat's claw vine , lantana , oleander and rubbervine . A pest management plan has been developed to supplement the annual weed control programme. The Gladstone Area Water Board has carried out vegetation re-establishment programs in order to replace remnant endangered regional ecosystems impacted by
1144-674: The dam was built by Thiess Brothers and was completed in March 1985. The dam reached its lowest level of 7.44% capacity in February 2003, and its highest recorded level of 192.9% (8.3m over the spillway) in January 2013 as a result of heavy rain from ex Tropical Cyclone Oswald . The dam continued spilling from 25 January until early May. When full the lake is 40 m (111 feet) above sea level. Approximately 200,000 fish are released each year including barramundi and some mangrove jack . By early 2006
1188-671: The fish disappeared.” The eggs of the silver perch are demersal and adhere to submerged roots, rushes, &c., in the vicinity of the eddies described. The observer considered what he had seen to be complete evidence of the spawning. Silver perch continue the trend in native fish of southeast Australia of having high potential longevity. Longevity is a survival strategy in the often challenging Australian environment to ensure that most adults participate in at least one exceptional spawning and recruitment event, which are often linked to unusually wet La Niña years and may occur only every one or two decades. Silver perch can be relatively long-lived;
1232-645: The flood events that remove fine sediment, and chronic siltation from poor agricultural practices, the eggs may now frequently land in anoxic fine sediment and organic matter — including in weir pools — and fail to survive. It may be that the section of the central Murray River that supports the last clearly viable natural population of silver perch primarily does so because it supplies a sufficiently long stretch of weir-free river, under standard regulated flows, for eggs to successfully complete their drift and hatch larvae into relatively natural, suitable riverine habitats for survival. Suspicions are also mounting that there
1276-412: The lake. Swimming is permitted from the shore and there is a 24-hour boat ramp that provides access for sailing, fishing, and skiing etc. Various watercraft, including house boats can be hired and organised. Fishing cruises are also available. The waters of Lake Awoonga are controlled by Queensland Boating and Fisheries Patrol and Queensland Water Police and all users of the lake are required to adhere to
1320-401: The lake. The lake hosts more than 225 species of birds. Species include the southern squatter pigeon which is listed as vulnerable and a further twenty-seven bird species listed on International Migratory Conservation Agreement Lists. The Gladstone Area Water Board has a fish breeding program in place and breeds barramundi and mangrove jack for stocking into Lake Awoonga as well as some of
1364-552: The lake. Barramundi in the 10–25 kg range are regularly caught from the lake. More than 415 plant varieties play a vital role in the health of the Lake Awoonga region. Ranging from vine thickets and rainforests to tall woodlands and grassy woodlands, they include over 45 confirmed species of aquatic plants such as ribbon weed , hornwort and sedges found in the shallow water areas. Aquatic plants have an important function in that they provide food and cover for animals, stabilise
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1408-525: The largest member of the Terapontidae, capable of growing in excess of 60 cm (24 in) and close to 8 kg (18 lb), but today wild river specimens are typically 30–40 cm (12–16 in) and 1.0–1.5 kg (2.2–3.3 lb). The silver perch is the only major representative of the family Terapontidae in the southern Murray-Darling system, compared to northern tropical systems where terapontid species are common. Another small terapontid,
1452-589: The largest stocks in Australia with more than 50,000 released. Other fish species include Agassiz's glass perch, banded grunter, barramundi, bony bream, eastern rainbowfish , eeltail catfish , fly-specked hardyhead, forktail catfish, gudgeon , long-finned eel, longtom , mouth almighty, sea mullet, snub-nose garfish and spangled perch. Also present in low numbers are Hyrtl's tandan, mangrove jack, saratoga , silver perch , sleepy cod , sooty grunter , and yellowbelly . Since 1996, over 2.5 million barramundi fingerlings and 470,000 mullet fingerlings have been released into
1496-435: The oldest individual aged so far was sampled from Cataract Dam, NSW (where a vitally important, self-sustaining, translocated population survives) and calculated to be 27 years old through otolith examination, while Murray River fish have been aged to 17 years old. However, recent (2017) research unexpectedly found only a small proportion of silver perch in the surviving Murray River population older than seven years of age. It
1540-485: The pelvic fins white. Silver perch are opportunistic feeders, feeding on insect larvae, molluscs, annelid worms and algae. The importance of vegetative matter in the diet of silver perch is still debated. Silver perch appear primarily to be a low-order predator of small aquatic invertebrate prey, with occasional intakes of small fish and vegetative matter. In aquaria, silver perch are reported to take blood worms readily. Silver perch are schooling mid-water fish with
1584-536: The posted speed limits. The lake is a popular fishing spot, especially for barramundi . The barramundi closed season does not apply to Lake Awoonga, although some limits do apply. Camping is permitted at two places on Lake Awoonga, the Caravan Park and the Boynedale Bush Camp. The main recreation area is provided free to the public and includes picnic shelters, barbecues, walking paths. The Boynedale Bush camp
1628-406: The river bottom against erosion and recycle nutrients. Several plants of conservation significance exist in the region Awoonga including Persoonia Amaliae and Eucalyptus melanoleuca which are listed as rare, while Cycas Megacarpa and Grevillea venusta are noted as vulnerable. Banksia integrifolia and Xanthorrhoea latifolia are common protected species that can also be found in
1672-399: The species' decline, and may explain the suspicious, very rapid collapse of some populations (e.g. upper Murrumbidgee). In a positive development, since 2000, the installation of fishways in many Murray River weirs, so that native fish can pass through them and successfully migrate long distances again, and recent carefully managed environmental flow events, have seen silver perch numbers in
1716-457: The species' survival in the wild. Such aquacultured silver perch are regularly stocked into numerous artificial impoundments where, without exception, they fail to establish self-sustaining populations. Reasons for the catastrophic decline of silver perch are only partially understood. Dams, weirs and river regulation and the virtual removal of spring floods appear to have removed the conditions silver perch need to breed and recruit successfully on
1760-425: The surface and others swimming about apparently aimlessly—in a series of eddies under a precipitous bank of the Murrumbidgee River, at a spot where the water was 10 or 12 foot deep. A section of the shoal, mostly the largest fish, remained in a central position. Suddenly, as though preconcerted, all the fish swam rapidly into a centre, splashing the water, in all directions, and becoming for an instant invisible owing to
1804-555: The surface at dusk or the first few hours of night. The female sheds the eggs and the male fertilizes them in a few seconds of vigorous thrashing. The eggs are semi-buoyant and will sink without significant current, and take 24 to 36 hours to hatch. A 1914 account describes a unique observation of silver perch spawning in the wild in the Murrumbidgee River: The observer of a shoal engaged in distributing ova says: “Between 50 and 70 silver perch were playing—some feeding at
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1848-578: The surrounding waterways. Approximately 200,000 fish are released into Lake Awoonga each year (200,000 barramundi and small numbers of mangrove jack). The fish are bred at a purpose-built fish hatchery, operated jointly by the Gladstone Area Water Board and the Gladstone Ports Corporation. The hatchery is one of the largest breeders of barramundi fingerlings in Queensland and their mangrove jack breeding program has resulted in Lake Awoonga holding
1892-586: The upland reaches of the Murrumbidgee were an annual event. Unfortunately these migrations, and these populations, have now collapsed — silver perch are functionally extinct in the Murrumbidgee River now, as in most parts of their former range. Silver perch have been introduced into the Lake Eyre Basin in arid central Australia. These releases were not officially sanctioned and pose serious hybridisation risks to closely related species of terapontids endemic to
1936-751: The western slopes of the range and flows generally north by east parallel with the Gladstone-Monto Road through the Boyne Valley . The river enters Lake Awoonga where it flows east by north, crossed by the Bruce Highway near Riverview, and finally discharging into the Port Curtis and the Coral Sea . The river descends 371 metres (1,217 ft) over its 125-kilometre (78 mi) course , joined by thirteen tributaries from source to river mouth . The mouth
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