In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||Listed as Critically Endangered|
|Listing and Conservation Advices||
Commonwealth Conservation Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel) (Threatened Species Scientific Committee (TSSC), 2011f) [Conservation Advice].
Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel) (Threatened Species Scientific Committee (TSSC), 2011h) [Listing Advice].
|Recovery Plan Decision||
Recovery Plan not required, the approved conservation advice for the species provides sufficient direction to implement priority actions and mitigate against key threats (23/12/2010).
|Adopted/Made Recovery Plans|
Federal Register of
Amendment to the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (110) (23/12/2010) (Commonwealth of Australia, 2010a) [Legislative Instrument].
|State Listing Status||
|Non-statutory Listing Status||
|Scientific name||Hyridella glenelgensis |
|Species author||(Dennant, 1898)|
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
Scientific name: Hyridella glenelgensis
Common name: Glenelg Freshwater Mussel
The Glenelg Freshwater Mussel is accepted as Hyridella glenelgensis (AFD 2010). However, studies have shown a close relationship with the Southern River Mussel (Hyridella narracanensis), a species found in isolated streams in Victoria, Tasmania and South Australia. The Southern River Mussel is found in Deep Creek and Eight Mile Creek, both sites in proximity to the Glenelg catchment in south-east South Australia. It is suggested that additional research is necessary to clarify the relationship of the two species (Playford & Walker 2008).
The Glenelg Freshwater Mussel is a sedentary, bivalve mollusc that attains 51–80 mm in length. The shell is strong and almond-shaped, with a rounded posterior border, and both the umbo (peak along the hinge line) and the shell surface are marked with fine sculpture (wrinkles). The Maximum Height Index (MHI), the ratio of maximum height of the shell to its length used to distinguish mollusks, is about 50% for the species. The periostracum (flaky shell covering) is olive-green in immature individuals and dark purple-brown in mature individuals (Playford & Walker 2008; Walker et al. 2001).
The Glenelg Freshwater Mussel is found only in the lower reaches of the Crawford River, a tributary of the Glenelg River, in south-west Victoria (Playford & Walker 2008). Two specimens at the Australian Museum are recorded from "Port Fairy" (McMichael & Hiscock 1958) but these are considered erroneous (Playford & Walker 2008).
The Glenelg Freshwater Mussel is now known as a single population in the lower reaches of the Crawford River, in localised patches of suitable habitat. The estimated total number of mature Glenelg Freshwater Mussels is less than 1000 (Playford & Walker 2008).
The Glenelg Freshwater Mussel is found in shallow, narrow, flowing sections of the Crawford River with dense riparian vegetation that shade the water thus moderating water temperatures. Woody debris from the riparian vegetation that falls into streams is an important habitat feature, providing stable sediments and a refuge from strong currents (Playford & Walker 2008).
The species lives in firm, coarse sandy sediments that supply ideal burrowing substrate, and allows feeding, respiratory and reproductive organs to function without clogging. The species is also reliant on flowing water as this assists in maintaining suitable water temperatures and restricting algal growth. Mussels burrow using their hard shell as a blade and a strong muscular 'foot' as an anchor, leaving only the hindmost part of their shell above the sediments. They may occur singly in marginal habitats, and in small aggregations or shoals in more favourable environments. Due to the physical attributes of the Glenelg Freshwater Mussel, it is suggested that the species favours smaller streams with less forceful water movements (Playford & Walker 2008).
Water quality is an important aspect of mussel habitat. Adult Glenelg Freshwater Mussels are likely to have an upper salinity tolerance of about 4 parts per thousand, similar to other Hyriidae mussels (Walker et al. 2001). Only the Crawford River and two smaller tributaries in the Glenelg River catchment consistently have salinities below this level in the known range of this species (Playford & Walker 2008).
Plant species found in riparian areas where the Glenelg Freshwater Mussel is located include Eucalyptus species, Blackwood (Acacia melanoxylon) and Woolly Tea-tree (Melaleuca lanigerum) (Playford & Walker 2008).
Within the class Bivalvia, mussel species from the Hyriidae family are considered long-lived, with some New Zealand species known to survive 7–33 years (MDFRC 2006). Based on other freshwater mussel species, the Glenelg Freshwater Mussel is likely to reach sexual maturity between 2–4 years of age (Byrne 1998; Jones et al. 1986).
The Glenelg Freshwater Mussel reproduces in summer, when mature males release spermatozoa into the water. Females take in the spermatozoa to fertilise eggs they have developed. Mature embryos are known as glochidia and are brooded in special pouches in the gills of female mussels for approximately 8 weeks before release (Jones et al. 1986). Glochidia are ectoparasites and attach to the gills or fins of a host fish that provides them with nutrition and dispersal during metamorphosis. The host fish for the Glenelg Freshwater Mussel are not known, but are likely to include a number of native species (Walker et al. 2001). Once the glochidia have metamorphosed to become juvenile mussels, they adopt the burrowing habit typical of the adults.
Spawning can be influenced by floods, water temperature, conditions of females and the presence or absence of host fish. If females are in good 'body' condition, multiple clutches may be spawned. Clutch sizes for the Glenelg Freshwater Mussel are not well known, but other larger mussel species can have clutches from less than 100 to more than 100 000 (Vic. DSE 2009t).
Glenelg Freshwater Mussels, like all Hyriidae mussels, are omnivorous filter feeders. They draw in water through a siphon, and food particles are trapped by ciliated ctenidia (gills), sorted and passed to the mouth. Food particles include phytoplankton (bacteria, algae), organic detritus and zooplankton. Feeding is assisted by normal stream flows delivering food particles to the gills (MDFRC 2006; Vic. DSE 2009t).
Sampling for the Glenelg Freshwater Mussel in suitable habitat can be done by feeling with fingers in the sediment (Playford & Walker 2008).
The Glenelg Freshwater Mussel may be hard to identify based on the fact that shell characteristics (shell shape, sculpture and hinge dentition), often used in field identification, can vary widely with local environmental conditions in streams. Great variation can be seen within populations (Walker et al. 2001) and age can wear identifying characteristics (Vic. DSE 2009t). One distinguishing feature between the Glenelg Freshwater Mussel and the closely related Southern River Mussel (H. narracanensis) is that the sculpture of Southern River Mussel is present only on the umbo (Playford & Walker 2008).
The Glenelg Freshwater Mussel may be confused with smaller specimens of Flood Plain Mussel (Velesunio ambiguous) though the former has a more rounded, ovoid shell (Vic. DSE 2009t).
Habitat loss and habitat degradation
Erosion, siltation and loss of riparian vegetation caused primarily by trampling and grazing stock affect the habitat of the Glenelg Freshwater Mussel. The species is not found where cattle have access to the river bank, as loss of vegetation increases soft silts in stream beds that can then clog feeding, respiratory and reproductive organs of the species, or bury them totally (Playford & Walker 2008). Loss of riparian vegetation also removes shading, increasing water temperatures and promoting algal growth that is unfavourable to mussels, and removes in stream debris that provides a refuge for mussels. De-snagging of the river system in the 1960s and 1970s is partly responsible for bank and bed instability and siltation, and may have contributed to the contraction of the local range of the species (Playford & Walker 2008). A study by Brainwood and colleagues (2006) suggests that the width of riparian vegetation surrounding populations may play an important protective role against surrounding land uses.
Habitat requirements of freshwater mussels' means they are often found 'patchily' in waterways, often in dense clusters. The reliance on specific substrate and water flows makes these species highly susceptible to any changes in riparian vegetation, water flows and sedimentation. Clearing of riparian areas, urban build-up close to streams, and intensive farming have all been implicated in the loss of freshwater mussel species within Australia and Northern America (Brainwood et al. 2006).
Low water flows may increase salinity, water temperatures and lower oxygen levels, all of which threatens the survival of the Glenelg Freshwater Mussel. The more shallow regions of streams, that are preferred habitat of the species, are prone to drying out during low flows, causing the species to burrow or follow the receding water. Cessations in flow can threaten the refuge habitats used by species in drier periods (Vic. DSE 2009t).
Periods of low flows and cessations in flow are increasing in the Crawford River due to growth in plantations in the area and drought. More than 18 000 ha of Eucalyptus spp. plantations have been established in the Crawford River sub-catchment since 1990, lowering water tables and causing reduced flows and drying of springs (SKM 2008 cited in FWPA 2009). Drought has also affected the catchment, with flow records since 1970 indicating an increase in months of low to nil flows (Vic. DSE 2009t).
Potential threats to the Glenelg Freshwater Mussel include pesticide use, predation and habitat degradation by introduced Carp (Cyprinus carpio), loss of native fish hosts for the glochidia, bushfires and impacts of timber harvesting (Brainwood et al. 2006; Playford & Walker 2008; Vic. DSE 2009t).
Freshwater mussels are affected by contamination of waterways by chemicals such as pesticides (Ruessler et al. 2009) due to their filter feeding habit that may cause them to see them accumulating large quantities of contaminants in tissue (ROPME 2010; Vic. DSE 2009t). Pesticides are used as part of eucalypt plantation forestry along the Crawford River catchment (FWPA 2009; Vic. DSE 2009t).
Introduced Carp first appeared in the Glenelg River in 2001 and are likely to invade the whole system, including the Crawford River (ASFB 2001; Vic. DPI 2010). Carp pose a serious predation risk to juvenile mussels, and also disturb bottom sediments, damage or destroy aquatic vegetation and compete with native fish. Experimental trials suggest that the glochidia of Australian freshwater mussel species may not utilise Carp as a host, but this requires confirmation (Walker 1981).
Bushfires can cause destruction of riparian and catchment vegetation and severe degradation of aquatic habitats (Vic. DSE 2009t).
Timber harvesting has the potential to degrade mussel habitat through large scale sediment inputs and siltation, especially if buffer zones are inadequate (Vic. DSE 2009t).
Minister's reasons for recovery plan decision
There should not be a recovery plan for Glenelg Freshwater Mussel as the approved Conservation Advice (TSSC 2011f) for the species provides sufficient direction to implement priority actions and mitigate against key threats.
Victorian action statement
The Victorian Department of Sustainability and Environment has outlined the following management actions to assist in the recovery of the Glenelg Freshwater Mussel (Vic. DSE 2009t):
- Ensure records of species, communities and locations are documented on the relevant databases.
- Increase the extent and improve condition of habitat.
- Maintain captive populations for research, identify reintroduction sites and prepare a plan for reintroduction.
- Increase knowledge of biology, ecology and management requirements.
- Conduct survey to locate additional populations and suitable habitat.
- Secure populations or habitat from potentially incompatible land use or catastrophic loss.
- Amend Crown Land reservation.
- Develop or amend planning scheme overlays and schedules.
- Develop/revise management prescriptions and/or zoning for state forest.
- Develop, provide input to or implement park, reserve or land management plan.
- Develop, publish and distribute educational, technical or publicity material and/or displays.
- Liaise with private landholders and government agencies.
- Fence habitat to allow natural regeneration.
The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.
|Threat Class||Threatening Species||References|
|Agriculture and Aquaculture:Livestock Farming and Grazing:Grazing pressures and associated habitat changes||Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel) (Threatened Species Scientific Committee (TSSC), 2011h) [Listing Advice].|
|Agriculture and Aquaculture:Livestock Farming and Grazing:Habitat alteration (vegetation, soil, hydrology) due to trampling and grazing by livestock||Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel) (Threatened Species Scientific Committee (TSSC), 2011h) [Listing Advice].|
|Biological Resource Use:Logging and Wood Harvesting:Habitat disturbance due to foresty activities||Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel) (Threatened Species Scientific Committee (TSSC), 2011h) [Listing Advice].|
|Biological Resource Use:Logging and Wood Harvesting:Habitat loss, modification and degradation due to timber harvesting|
|Climate Change and Severe Weather:Droughts:Drought|
|Climate Change and Severe Weather:Droughts:Natural and artifically induced reductions to surface water availability|
|Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat loss, modification and/or degradation|
|Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification with associated erosion|
|Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification, destruction and alteration due to changes in land use patterns|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition, predation and/or habitat degradation||Cyprinus carpio (European Carp, Common Carp)|
|Natural System Modifications:Dams and Water Management/Use:Changes to habitat hydrology|
|Natural System Modifications:Dams and Water Management/Use:Salinity|
|Natural System Modifications:Fire and Fire Suppression:Inappropriate fire regimes including natural wildfires|
|Natural System Modifications:Other Ecosystem Modifications:Removal of wood snags from waterways|
|Pollution:Agricultural Effluents:Pesticide application|
Australian Society for Fish Biology (ASFB) (2001). Alien Fishes Committee Report - May 2001. [Online]. Available from: http://www.asfb.org.au/research/Alien%20Fishes%20Comm./escr200105.htm.
Brainwood, M., S. Burgin & M. Byrne (2006). Is the decline of freshwater mussel populations in a regulated coastal river in south-eastern Australia linked with human modification of habitat?. Aquatic Conservation: Marine and Freshwater Ecosystems. 16:501-516.
Byrne, M. (1998). Reproduction of river and lake populations of Hyridella depressa (Unionacea: Hyriidae) New South Wales: implications for their conservation. Hydrobiologia. 389:29-43.
Forest & Wood Products Australia (FWPA) (2009). Sustainability and Resources. Project no: PNC064-0607 June 2009 - Plantation forest water use in southwest Victoria. [Online]. Available from: http://www.fwpa.com.au/Resources/RD/Reports/PNC064-0607_Plantation_Water_Use_Research_Report.pdf?c=1&pn=PNC064-0607.
Jones, H., R.D. Simpson & C.L. Humphrey (1986). The reproductive cycles and glochidia of freshwater mussels (Bivalvia: Hyriidae) of the Macleay River, northern New South Wales, Australia. Malacologia. 27:185-202.
McMichael, D.F. & I.D. Hiscock (1958). A monograph of the freshwater mussels (Mollusca: Pelecypoda) of the Australian region. Australian Journal of Marine and Freshwater Research. 9:372-508.
Murray Darling Freshwater Research Centre (MDFRC) (2006). Identification and Ecology of Australian Freshwater invertebrates- Unionoida, Hyriidae and Bivalvia (mussels). [Online]. Available from: http://www.mdfrc.org.au/bugguide/display.asp?class=22&subclass=&order=42&Couplet=0&Type=3.
Playford, T.J. & K.F. Walker (2008). Status of the endangered Glenelg River Mussel Hyridella glenelgensis (Unionoida: Hyriidae) in Australia. Aquatic Conservation: Marine and Freshwater Ecosystems. 18:679-691.
Regional Organization for the Protection of Marine Environments (ROPME) (2010). Mussel Watch Program. [Online]. Available from: http://www.ropme.com/program3.html.
Ruessler, D.S., N.J. Kernaghan, C.M. Wieser, J.J. Wiebe & T.S. Gross (2009). An Assessment of Potential Contaminant Effects on Freshwater Mussels in the South Florida Ecosystem. [Online]. Southeast Ecological Science Centre U.S. Geological Survey, USA. Available from: http://fl.biology.usgs.gov/posters/Ecotoxicology/Contaminants_Effect_Mussels/contaminants_effect_mussels.html.
Threatened Species Scientific Committee (TSSC) (2011f). Commonwealth Conservation Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel). [Online]. Department of Sustainability, Environment, Water, Population and Communities. Canberra, ACT: Department of Sustainability, Environment, Water, Population and Communities. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/82953-conservation-advice.pdf.
Threatened Species Scientific Committee (TSSC) (2011h). Commonwealth Listing Advice on Hyridella glenelgensis (Glenelg Freshwater Mussel). [Online]. Department of Sustainability, Environment, Water, Population and Communities. Canberra, ACT: Department of Sustainability, Environment, Water, Population and Communities. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/82953-listing-advice.pdf.
Victorian Department of Primary Industries (Vic. DPI) (2010). Angling Waters of the Glenelg River Basin. [Online]. Available from: http://www.dpi.vic.gov.au/angling/38-Glenelg/Basin%20TEMPLATE%20Waters.htm.
Victorian Department of Sustainability and Environment (Vic. DSE) (2009t). Draft Flora and Fauna Guarantee Action Statement-Glenelg Freshwater Mussel Hyridella glenelgensis. [Online]. Available from: http://www.dse.vic.gov.au/CA256F310024B628/0/267883776C8F91C2CA25764F0013FC14/$File/Glenelg+Freshwater+Mussel+july+2009.pdf.
Walker, K.F. (1981). Ecology of freshwater mussels in the River Murray. Australian Water Resources Council Technical Paper.
Walker, K.F., M. Byrne, C.W. Hickey & D.S. Roper (2001). Freshwater mussels (Hyriidae) of Australasia. In: Bauer, G & W. Wächtler, eds. Ecology and evolution of the freshwater mussels Unionida. Ecological Studies. 145:5-31.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2014). Hyridella glenelgensis in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sun, 21 Sep 2014 20:50:54 +1000.