Documenting the diet of organisms that have been introduced and naturalised outside their native ... more Documenting the diet of organisms that have been introduced and naturalised outside their native range is a fundamental component of understanding their trophic interrelations in the receiving environment, and for developing holistic management practices for introduced species' predation impacts in an ecosystem. We describe two accounts of terrestrial reptiles in the diet of an introduced fish, rainbow trout Oncorhynchus mykiss in southern NSW, Australia. Our observations from the Southern Hemisphere together with recently published records from the Northern Hemisphere (e.g. USA, France and Italy) represent the presence of reptiles in the diet of O. mykiss across a broad geographical range and highlight a potential additional consideration of introduced salmonids and their impacts on terrestrial species.
In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species... more In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae. Although these nematodes have frequently been reported in Australian fish, reptiles, and birds and cause disease or mortality among them, there has been no attempt to date to characterise them genetically. Globally, also, no one has validated or defined suitable genetic markers to distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus, n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids (Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological examination and molecular characterisation. The adult nematodes from cormorants were iden- tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes, which were identical among all specimens (larvae and adults) and also identical to those of E. excisus available in the GenBank. However, only one base pair difference exists between the 18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom- panied with proper morphological data for the nematodes. With that limitation in mind, identi- fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that has successfully established its life cycle among Australian native species – may have occurred. Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do not exclude the possibility of the occurrence of other species of Eustrongylides, either native or exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter- ation affecting the reproductive success of the infected hosts. Therefore, awareness among the relevant authorities of the presence of the parasite in Australia and its adverse impact on native animals is crucial for the success of conservation plans such as fish recovery and relocation efforts
In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species... more In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae. Although these nematodes have frequently been reported in Australian fish, reptiles, and birds and cause disease or mortality among them, there has been no attempt to date to characterise them genetically. Globally, also, no one has validated or defined suitable genetic markers to distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus, n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids (Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological examination and molecular characterisation. The adult nematodes from cormorants were iden- tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes, which were identical among all specimens (larvae and adults) and also identical to those of E. excisus available in the GenBank. However, only one base pair difference exists between the 18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom- panied with proper morphological data for the nematodes. With that limitation in mind, identi- fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that has successfully established its life cycle among Australian native species – may have occurred. Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do not exclude the possibility of the occurrence of other species of Eustrongylides, either native or exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter- ation affecting the reproductive success of the infected hosts. Therefore, awareness among the relevant authorities of the presence of the parasite in Australia and its adverse impact on native animals is crucial for the success of conservation plans such as fish recovery and relocation efforts
International Journal of Environmental Research and Public Health
Aquatic snails serve an important role in the ecosystem. They also play an essential role in the ... more Aquatic snails serve an important role in the ecosystem. They also play an essential role in the life cycle of many parasites as hosts and may pose risks to animal and human health. In Australia, the role of snails in the transmission of parasites of livestock is well studied. However, despite the country’s unique biodiversity and wildlife, little is known about the role of snails in the transmission and survival of parasites in other ecosystems, including aquatic and aquaculture systems. This study aimed to determine the occurrence of parasites in freshwater snails in the eastern Murray Darling Basin. A total of 275 snails were collected from various localities, including aquaculture fishery ponds and natural creeks during the summer and autumn months in the southern hemisphere. Three different species of freshwater snails, all common to the area, were found, including Bullastra lessoni (n = 11), Isidorella hainesii (n = 157), and Haitia acuta (n = 107), of which 9.1%, 1.3%, and 4....
International Journal of Environmental Research and Public Health, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural product... more The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural production and supporting a population of over 4 million people. Historically, the MDB supported a unique native fish community with significant cultural, subsistence, recreational, commercial and ecological values. Approximately one-quarter of the MDB’s native species are endemic. Changes to river flows and habitats have led to a >90% decline in native fish populations over the past 150 years, with almost half the species now of conservation concern. Commercial fisheries have collapsed, and important traditional cultural practices of First Nations People have been weakened. The past 20 years have seen significant advances in the scientific understanding of native fish ecology, the effects of human-related activities and the recovery measures needed. The science is well established, and some robust restoration-enabling policies have been initiated to underpin actions. What is now required is...
Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contem... more Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contemporary ecological knowledge to guide management. This compendium contains knowledge collated from over 600 publications and 27 expert workshops to support the restoration of 9 priority native freshwater fish species, representative of the range of life-history strategies and values in south-eastern Australia’s Murray–Darling Basin. To help prioritise future research investment and restoration actions, ecological knowledge and threats were assessed for each species and life stage. There is considerable new knowledge (80% of publications used were from the past 20 years), but this varied among species and life stages, with most known about adults, then egg, juvenile and larval stages (in that order). The biggest knowledge gaps concerned early life stage requirements, survival, recruitment, growth rates, condition and movements. Key threats include reduced longitudinal and lateral connectiv...
Coppabella Creek in the Upper Murray Catchment near Tumbarumba supports one of only three remaini... more Coppabella Creek in the Upper Murray Catchment near Tumbarumba supports one of only three remaining populations of the endangered Southern Pygmy Perch (Nannoperca australis) in NSW. Murray Local Land Services (MLLS) and formerly Murray Catchment Management Authority (MCMA) have been actively providing funding and undertaking rehabilitation measures aimed at protecting, maintaining and improving the Southern Pygmy Perch population within Coppabella Creek since 2006. Summary of sampling to date The Southern Pygmy Perch population within Coppabella Creek suffered significant declines post the catastrophic flooding event that occurred in October 2010. This and subsequent flooding events in both 2011 and 2012 caused major changes to the morphology of the stream, the habitat and the fish community. As part of a long term monitoring program, a survey of the freshwater fish community of Coppabella Creek was undertaken by Fisheries NSW in November 2014. This survey was aimed at determining the current distribution, and relative abundance of Southern Pygmy Perch within the system as well as population trends over time. Summary of survey results Standardised sampling of ten sites spread along the 38km length of Coppabella Creek, yielded a catch of 111 fish and an estimated additional 19 individuals of eight species of fish were observed from the 10 sites. Only 3 individual Southern Pygmy Perch where captured (from the 2 upper most sites). However dip netting produced a much greater number of Southern Pygmy Perch from the sites where they where identified via the standardised sampling, along with one extra site where standardised sampling did not detect them. The most abundant species sampled was Common Carp with 52 individuals captured and 14 observed. The nest most abundant species captured was River Blackfish with 42 individuals captured and 5 observed, the remaining 5 species were all detected in relatively low abundances. Summary of key recommendations • Maintain existing barrier to alien fish passage • Investigate potential for additional improved barrier downstream of existing barrier • Investigate the potential removal of pest fish from a section of the creek between barriers • Stock limitation or exclusion from riparian areas • Ongoing weed control • Reestablishment of native vegetation • Identify potential translocation/reintroduction sites • Develop translocation/stocking strategies • Continue to monitor of the current population and any potential translocation sites. • Establish a captive breeding and re-introduction program. • Refrain from stocking trout or other predatory fish species into know Southern Pygmy Perch habitats.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Executive summary Background Macquarie perch (MP; Macquaria australasica Cuvier 1830) were histor... more Executive summary Background Macquarie perch (MP; Macquaria australasica Cuvier 1830) were historically widespread throughout the southern Murray–Darling Basin (MDB), but have substantially declined in terms of their abundance and distribution since the 1900s. The species is now listed as nationally endangered, and there is only one known remaining population in the NSW Murray region — in Mannus Creek, within the Upper Murray area. Despite the threat of localised extinction to MP in the NSW Murray region, little is known about the status of the Mannus Creek population, or how best to manage the creek’s habitat conditions to ensure the species’ persistence and recovery in the region long term. The current project was undertaken to: 1. determine if MP still persist within Mannus Creek, and if they do, 2. examine the abundance and distribution of MP within Mannus Creek 3. assess Mannus Creek for suitable habitat and refuge for MP, and identify any deficiencies or major threats 4. develop a long-term management plan for the Mannus Creek system. Findings There is a small, self-sustaining MP population still present in Mannus Creek, inhabiting the 9-km section immediately downstream of Mannus Falls and within Bogandyera Nature Reserve. This section of the creek is characterised by the presence of a relatively high proportion of flowing habitat (runs and/or riffles) and an abundance of coarse rock piles. Principal component analysis showed that the three studied reaches of Mannus Creek (upstream of Mannus Dam, between Mannus Dam and Mannus Falls and downstream of Mannus Falls) were significantly different in regards to habitat feature composition; particularly when comparing the upper reach (upstream of the Mannus Dam) with the lower reach (downstream of Mannus Falls). Multiple regression analyses confirmed that MP abundance was significantly positively associated with the occurrence of run habitat and boulders, especially during the autumn/winter. Canonical correspondence analysis determined that the presence of MP was mostly influenced by coarse rock substrate (cobble, boulder and bedrock). Results from the only other existing MP habitat association study reported similar findings for a remnant population in the upper Lachlan catchment — with MP occurrence found to be mainly determined by the availability of flowing habitats (riffles and runs) as well as the availability of small complex rock piles (aggregations of boulders of 0.5–1 m diameter) for cover (Gilligan et al. 2010b).
Documenting the diet of organisms that have been introduced and naturalised outside their native ... more Documenting the diet of organisms that have been introduced and naturalised outside their native range is a fundamental component of understanding their trophic interrelations in the receiving environment, and for developing holistic management practices for introduced species' predation impacts in an ecosystem. We describe two accounts of terrestrial reptiles in the diet of an introduced fish, rainbow trout Oncorhynchus mykiss in southern NSW, Australia. Our observations from the Southern Hemisphere together with recently published records from the Northern Hemisphere (e.g. USA, France and Italy) represent the presence of reptiles in the diet of O. mykiss across a broad geographical range and highlight a potential additional consideration of introduced salmonids and their impacts on terrestrial species.
In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species... more In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae. Although these nematodes have frequently been reported in Australian fish, reptiles, and birds and cause disease or mortality among them, there has been no attempt to date to characterise them genetically. Globally, also, no one has validated or defined suitable genetic markers to distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus, n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids (Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological examination and molecular characterisation. The adult nematodes from cormorants were iden- tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes, which were identical among all specimens (larvae and adults) and also identical to those of E. excisus available in the GenBank. However, only one base pair difference exists between the 18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom- panied with proper morphological data for the nematodes. With that limitation in mind, identi- fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that has successfully established its life cycle among Australian native species – may have occurred. Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do not exclude the possibility of the occurrence of other species of Eustrongylides, either native or exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter- ation affecting the reproductive success of the infected hosts. Therefore, awareness among the relevant authorities of the presence of the parasite in Australia and its adverse impact on native animals is crucial for the success of conservation plans such as fish recovery and relocation efforts
In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species... more In Australia, nematodes belonging to the genus Eustrongylides were believed to be endemic species until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae. Although these nematodes have frequently been reported in Australian fish, reptiles, and birds and cause disease or mortality among them, there has been no attempt to date to characterise them genetically. Globally, also, no one has validated or defined suitable genetic markers to distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus, n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids (Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological examination and molecular characterisation. The adult nematodes from cormorants were iden- tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes, which were identical among all specimens (larvae and adults) and also identical to those of E. excisus available in the GenBank. However, only one base pair difference exists between the 18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom- panied with proper morphological data for the nematodes. With that limitation in mind, identi- fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that has successfully established its life cycle among Australian native species – may have occurred. Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do not exclude the possibility of the occurrence of other species of Eustrongylides, either native or exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter- ation affecting the reproductive success of the infected hosts. Therefore, awareness among the relevant authorities of the presence of the parasite in Australia and its adverse impact on native animals is crucial for the success of conservation plans such as fish recovery and relocation efforts
International Journal of Environmental Research and Public Health
Aquatic snails serve an important role in the ecosystem. They also play an essential role in the ... more Aquatic snails serve an important role in the ecosystem. They also play an essential role in the life cycle of many parasites as hosts and may pose risks to animal and human health. In Australia, the role of snails in the transmission of parasites of livestock is well studied. However, despite the country’s unique biodiversity and wildlife, little is known about the role of snails in the transmission and survival of parasites in other ecosystems, including aquatic and aquaculture systems. This study aimed to determine the occurrence of parasites in freshwater snails in the eastern Murray Darling Basin. A total of 275 snails were collected from various localities, including aquaculture fishery ponds and natural creeks during the summer and autumn months in the southern hemisphere. Three different species of freshwater snails, all common to the area, were found, including Bullastra lessoni (n = 11), Isidorella hainesii (n = 157), and Haitia acuta (n = 107), of which 9.1%, 1.3%, and 4....
International Journal of Environmental Research and Public Health, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural product... more The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural production and supporting a population of over 4 million people. Historically, the MDB supported a unique native fish community with significant cultural, subsistence, recreational, commercial and ecological values. Approximately one-quarter of the MDB’s native species are endemic. Changes to river flows and habitats have led to a >90% decline in native fish populations over the past 150 years, with almost half the species now of conservation concern. Commercial fisheries have collapsed, and important traditional cultural practices of First Nations People have been weakened. The past 20 years have seen significant advances in the scientific understanding of native fish ecology, the effects of human-related activities and the recovery measures needed. The science is well established, and some robust restoration-enabling policies have been initiated to underpin actions. What is now required is...
Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contem... more Many freshwater fishes are imperilled globally, and there is a need for easily accessible, contemporary ecological knowledge to guide management. This compendium contains knowledge collated from over 600 publications and 27 expert workshops to support the restoration of 9 priority native freshwater fish species, representative of the range of life-history strategies and values in south-eastern Australia’s Murray–Darling Basin. To help prioritise future research investment and restoration actions, ecological knowledge and threats were assessed for each species and life stage. There is considerable new knowledge (80% of publications used were from the past 20 years), but this varied among species and life stages, with most known about adults, then egg, juvenile and larval stages (in that order). The biggest knowledge gaps concerned early life stage requirements, survival, recruitment, growth rates, condition and movements. Key threats include reduced longitudinal and lateral connectiv...
Coppabella Creek in the Upper Murray Catchment near Tumbarumba supports one of only three remaini... more Coppabella Creek in the Upper Murray Catchment near Tumbarumba supports one of only three remaining populations of the endangered Southern Pygmy Perch (Nannoperca australis) in NSW. Murray Local Land Services (MLLS) and formerly Murray Catchment Management Authority (MCMA) have been actively providing funding and undertaking rehabilitation measures aimed at protecting, maintaining and improving the Southern Pygmy Perch population within Coppabella Creek since 2006. Summary of sampling to date The Southern Pygmy Perch population within Coppabella Creek suffered significant declines post the catastrophic flooding event that occurred in October 2010. This and subsequent flooding events in both 2011 and 2012 caused major changes to the morphology of the stream, the habitat and the fish community. As part of a long term monitoring program, a survey of the freshwater fish community of Coppabella Creek was undertaken by Fisheries NSW in November 2014. This survey was aimed at determining the current distribution, and relative abundance of Southern Pygmy Perch within the system as well as population trends over time. Summary of survey results Standardised sampling of ten sites spread along the 38km length of Coppabella Creek, yielded a catch of 111 fish and an estimated additional 19 individuals of eight species of fish were observed from the 10 sites. Only 3 individual Southern Pygmy Perch where captured (from the 2 upper most sites). However dip netting produced a much greater number of Southern Pygmy Perch from the sites where they where identified via the standardised sampling, along with one extra site where standardised sampling did not detect them. The most abundant species sampled was Common Carp with 52 individuals captured and 14 observed. The nest most abundant species captured was River Blackfish with 42 individuals captured and 5 observed, the remaining 5 species were all detected in relatively low abundances. Summary of key recommendations • Maintain existing barrier to alien fish passage • Investigate potential for additional improved barrier downstream of existing barrier • Investigate the potential removal of pest fish from a section of the creek between barriers • Stock limitation or exclusion from riparian areas • Ongoing weed control • Reestablishment of native vegetation • Identify potential translocation/reintroduction sites • Develop translocation/stocking strategies • Continue to monitor of the current population and any potential translocation sites. • Establish a captive breeding and re-introduction program. • Refrain from stocking trout or other predatory fish species into know Southern Pygmy Perch habitats.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial ... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Executive summary Background Macquarie perch (MP; Macquaria australasica Cuvier 1830) were histor... more Executive summary Background Macquarie perch (MP; Macquaria australasica Cuvier 1830) were historically widespread throughout the southern Murray–Darling Basin (MDB), but have substantially declined in terms of their abundance and distribution since the 1900s. The species is now listed as nationally endangered, and there is only one known remaining population in the NSW Murray region — in Mannus Creek, within the Upper Murray area. Despite the threat of localised extinction to MP in the NSW Murray region, little is known about the status of the Mannus Creek population, or how best to manage the creek’s habitat conditions to ensure the species’ persistence and recovery in the region long term. The current project was undertaken to: 1. determine if MP still persist within Mannus Creek, and if they do, 2. examine the abundance and distribution of MP within Mannus Creek 3. assess Mannus Creek for suitable habitat and refuge for MP, and identify any deficiencies or major threats 4. develop a long-term management plan for the Mannus Creek system. Findings There is a small, self-sustaining MP population still present in Mannus Creek, inhabiting the 9-km section immediately downstream of Mannus Falls and within Bogandyera Nature Reserve. This section of the creek is characterised by the presence of a relatively high proportion of flowing habitat (runs and/or riffles) and an abundance of coarse rock piles. Principal component analysis showed that the three studied reaches of Mannus Creek (upstream of Mannus Dam, between Mannus Dam and Mannus Falls and downstream of Mannus Falls) were significantly different in regards to habitat feature composition; particularly when comparing the upper reach (upstream of the Mannus Dam) with the lower reach (downstream of Mannus Falls). Multiple regression analyses confirmed that MP abundance was significantly positively associated with the occurrence of run habitat and boulders, especially during the autumn/winter. Canonical correspondence analysis determined that the presence of MP was mostly influenced by coarse rock substrate (cobble, boulder and bedrock). Results from the only other existing MP habitat association study reported similar findings for a remnant population in the upper Lachlan catchment — with MP occurrence found to be mainly determined by the availability of flowing habitats (riffles and runs) as well as the availability of small complex rock piles (aggregations of boulders of 0.5–1 m diameter) for cover (Gilligan et al. 2010b).
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until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae.
Although these nematodes have frequently been reported in Australian fish, reptiles, and birds
and cause disease or mortality among them, there has been no attempt to date to characterise
them genetically. Globally, also, no one has validated or defined suitable genetic markers to
distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black
cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus,
n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids
(Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological
examination and molecular characterisation. The adult nematodes from cormorants were iden-
tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes,
which were identical among all specimens (larvae and adults) and also identical to those of
E. excisus available in the GenBank. However, only one base pair difference exists between the
18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom-
panied with proper morphological data for the nematodes. With that limitation in mind, identi-
fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that
has successfully established its life cycle among Australian native species – may have occurred.
Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do
not exclude the possibility of the occurrence of other species of Eustrongylides, either native or
exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing
dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the
flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter-
ation affecting the reproductive success of the infected hosts. Therefore, awareness among the
relevant authorities of the presence of the parasite in Australia and its adverse impact on native
animals is crucial for the success of conservation plans such as fish recovery and relocation efforts
until the late 20th century when they were all considered to be E. excisus, invalid or inquirendae.
Although these nematodes have frequently been reported in Australian fish, reptiles, and birds
and cause disease or mortality among them, there has been no attempt to date to characterise
them genetically. Globally, also, no one has validated or defined suitable genetic markers to
distinguish between species of Eustrongylides. In this study, adult Eustrongylides from little black
cormorant (Phalacrocorax sulcirostris; n = 3) and larvae from mountain galaxias (Galaxias olidus,
n = 2) and a Murray cod (Maccullochella peelii, n = 1), and a Murray cod-trout cod hybrids
(Maccullochella peelii x Maccullochella macquariensis, n = 1) were available for morphological
examination and molecular characterisation. The adult nematodes from cormorants were iden-
tified as E. excisus. Sequences of the 18S and ITS regions were then obtained for all nematodes,
which were identical among all specimens (larvae and adults) and also identical to those of
E. excisus available in the GenBank. However, only one base pair difference exists between the
18S sequences of E. excisus and E. ignotus, with limited sequences available in GenBank accom-
panied with proper morphological data for the nematodes. With that limitation in mind, identi-
fying our specimens as E. excisus suggests spill-over – that it is an introduced parasite species that
has successfully established its life cycle among Australian native species – may have occurred.
Our study is the first report of E. excisus in the little black cormorant, P. sulcirostris. Our results do
not exclude the possibility of the occurrence of other species of Eustrongylides, either native or
exotic, in Australia. This parasite is zoonotic and with increasing demand for fish and changing
dietary preferences, such as the consumption of raw or undercooked fish, its occurrence in the
flesh of the fish is concerning. This parasite is also associated with anthropogenic habitat alter-
ation affecting the reproductive success of the infected hosts. Therefore, awareness among the
relevant authorities of the presence of the parasite in Australia and its adverse impact on native
animals is crucial for the success of conservation plans such as fish recovery and relocation efforts