The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Joni Torsella - One of the best experts on this subject based on the ideXlab platform.
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feasibility of micronucleus methods for monitoring genetic damage in two Feral Species of small mammals
Environmental and Molecular Mutagenesis, 1999Co-Authors: John R Meier, Paul Wernsing, Joni TorsellaAbstract:Peromyscus leucopus (white-footed mouse) and Cryptotis parva (least shrew) possess desirable attributes for biomonitoring contamination of terrestrial ecosystems, but few studies have examined the potential use of these Species for monitoring exposure to genotoxic contaminants. The susceptibility of laboratory-reared C. parva, P. leucopus, and Mus musculus (house mouse, strain CD-1) to micronucleus (MN) induction by known clastogens was evaluated. Animals were exposed for 24 hr to methyl methanesulfonate (MMS; 12.5, 25, and 50 mg/kg), 4-nitroquinoline 1-oxide (4-NQO; 7.5, 15, and 30 mg/kg), or mercuric chloride (HgCl 2 ; 6, 12, and 24 mg/kg). Both MMS and 4-NQO induced dose-related increases in micronucleated polychromatic erythrocytes (MNPCE) in all three Species, whereas HgCl 2 induced a weak response only in P. leucopus. P. leucopus and C. parva were more sensitive than M. musculus to MMS. Similar micronucleus responses to 4-NQO were seen in each of the Species. The feasibility of using blood for MN assessment was evaluated by comparing MN frequencies in bone marrow (BM) PCE, and blood PCE and normochromatic erythrocytes (NCE) in untreated animals, and following daily treatment for 1, 2, 3, and 10 days with 0.4 mg/kg triethylenemelamine (TEM). The results indicated that micronucleated erythrocytes were removed from the circulating blood in P. leucopus, but not in C. parva. Measurement of BM and blood MN levels appears feasible for monitoring exposure to genotoxic agents in C. parva and P. leucopus, and for distinguishing between acute and chronic exposure in C. parva.
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Comparative sensitivity of small mammals to micronucleus induction in bone marrow cells by clastogenic compounds
1995Co-Authors: John R Meier, Paul Wernsing, F.b. Daniel, Joni TorsellaAbstract:The bone marrow micronucleus assay is the most widely used method for detecting genetic damage in vivo, but this assay has received little attention for its possible application to biomonitoring terrestrial environments. The present study compared the responsiveness of three small mammalian Species, Cryptotus parva (least shrew), Peromyscus leucopus (white-footed mouse), and strain CD-1 Mus musculus (house mouse), to the clastogen, methylmethanesulfonate (MMS). Five animals of each sex of each Species were exposed for 24 h to four concentrations of MMS ranging from 0 to 50 mg/kg. Bone marrow cells were flushed from the femurs, and smears were stained with acridine orange and examined using fluorescence microscopy. The slides were scored for evidence of acute bone marrow toxicity (polychromatic to normochromatic erythrocyte ratio, PCE:NCE) and frequency of micronucleated PCE. PCE:NCE was depressed at 50 mg/kg in P. leucopus, but not in the other Species. Dose-related increases in micronucleated PCE were observed in all three Species, with males being more sensitive for P. leucopus and M. musculus, and females being more sensitive for C. parva. For both sexes, the two Feral Species, P. leucopus and C. parva, were more sensitive than M. musculus. These studies demonstrate the successful application of themore » bone marrow micronucleus assay to Species other than standard laboratory strains of mice. The results also demonstrate heretofore unrecognized Species differences in responsiveness.« less
Stephen J. Beatty - One of the best experts on this subject based on the ideXlab platform.
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Margaret River Fishway
2020Co-Authors: David L. Morgan, Stephen J. BeattyAbstract:In order to enhance the migrations of fish Species in the Margaret River, the Margaret River Regional Environment Centre, in conjunction with the Department of Environment, constructed a rock ramp fishway at the Margaret River Weir (Apex Weir) between March and April 2003. Morgan and Beatty (2003) surveyed the fish fauna of the river during March 2003, capturing 9206 fish from five native Species, one Feral Species and the pouched lamprey (Geotria australis) (see Plate 1). All of the native fishes of the river are endemic to south-western Australia while the Feral Species is the mosquitofish (Gambusia holbrooki). The only other records of fish from the river are those recorded by Morgan et al. (1998) and there are also a few records in the Western Australian Museum. Large numbers of native fishes were known to be impeded by the town weir on their upstream migration during winter and spring. These native fishes included the western minnow (Galaxias occidentalis), western pygmy perch (Edelia vittata) and nightfish (Bostockia porosa). Furthermore, adult lampreys were often observed negotiating the weirs on Margaret River with the occasional dead animal also observed. The reservoir above the Margaret River Weir had the highest abundance of the Feral mosquitofish with this section of the river also containing western minnows, nightfish and western pygmy perch, and beds for larval lampreys (ammocoetes) (Morgan and Beatty 2003). It was thus deemed appropriate that the construction of a fishway on the Margaret River would be beneficial to fish and lamprey migrations in the Margaret River.
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Little fish under threat in a big state: south-western Western Australia’s endemic freshwater fishes
2020Co-Authors: Stephen J. Beatty, David L. MorganAbstract:Widespread habitat alterations and impacts of Feral Species have led to range reductions and population declines of south‐western Australia’s highly endemic freshwater fishes. Some Species have been lost from systems and/or are restricted to specific habitats within catchments. Habitat alterations primarily due to salinisation, water extraction and river regulation have compromised many populations. Recent studies on distributions, habitat associations, salinity tolerances, migratory patterns and fishway utilisation has greatly increased our understanding of these key threats and has enabled us to identify populations at greatest risk and to begin to predict future viabilities. This research is currently being used to prioritise populations and develop strategies to help ensure their ongoing sustainability.
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Fish fauna of the Vasse River and the colonisation by Feral goldfish (Carassius auratus)
2020Co-Authors: David L. Morgan, Stephen J. BeattyAbstract:During December 2003 and March 2004 a total of 7895 fish from nine Species were captured during a survey of the Vasse River, including two sites in the Vasse River Diversion Drain. Of the fish captured, four were native freshwater fishes that are endemic to the south-west, three were native estuarine Species and two were introduced fishes. Two estuarine Species dominated the native catches with the western hardyhead (Leptatherina wallacei) being captured at the most downstream sites and the Swan River goby (Pseudogobius olorum) being captured throughout the river aside from the upper-most headwater site. The endemic western pygmy perch (Edelia vittata) was also widely distributed in the river, however, it was captured in relatively low numbers aside from immediately downstream of the Diversion Drain at a site with more complex in-stream and riparian habitat. The western minnow (Galaxias occidentalis) and nightfish (Bostockia porosa) were only captured in relatively low numbers at two sites each in the lower Vasse River. This study also captured the rare mud minnow (Galaxiella munda) at the headwater site, which is the first record of this Species in the Vasse River. The Vasse River is generally heavily modified and two introduced Feral Species, the mosquitofish (Gambusia holbrooki) and goldfish (Carassius auratus) have become established and accounted for over 60% of all fish captures. These Species were particularly dominant in more degraded reaches of the river, such as the Diversion Drain and the lower Vasse River. The goldfish were captured in the lower Vasse River, between the Diversion Drain and immediately below the Old Butter Factory slot-boards. This stretch of the river has essentially become a heavily silted, stagnant pool due to the restriction of flow from the Diversion Drain and the presence of slot-boards, which together prevent adequate flushing of the system and that is likely to have facilitated the establishment of the Feral Species, as well as exacerbating algal blooms. It is suggested that the introduction of goldfish into the Vasse River is relatively recent and the dominance of juveniles born in October last year will result in a rapid increase in the population in the next few years. Growth rates of goldfish in the Vasse River far exceed those reported elsewhere with individuals attaining lengths of over 180 mm TL at the end of their first year, the age at which they also mature. Goldfish are known to be vectors for disease introduction, may prey on native fish and their eggs and larvae, reduce aquatic plant biomass and re-suspend nutrients further fuelling algal blooms. Furthermore, recent studies have demonstrated that significant growth of cyanobacteria is stimulated by the passage through goldfish intestines. Goldfish, which attained lengths of over 40 cm in the Vasse River, therefore have the potential to contribute to algal blooms. It is recommended that flushing of the river could occur by removal of the slot-boards at the Old Butter Factory and diverting flows from the Diversion Drain back into the river, thus attempting to return environmental flows to a more natural regime. Riparian vegetation should also continue to occur in this stretch of the River with estuarine Species able to tolerate the higher salinities expected to occur as the River returns to a more natural, estuarine system. A goldfish eradication program should be implemented in the lower Vasse River. This program would also provide an excellent opportunity to gain further information on their biology and ecological impact in the system, particularly with regard to their role in algal blooms. An education program should also be implemented outlining the problems caused by releasing aquarium fish into wild aquatic systems.
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Mitigating the impact of Serpentine Dam works on Carter’s Freshwater Mussel
2020Co-Authors: M.w. Klunzinger, Stephen J. Beatty, Mark G. Allen, J. KeleherAbstract:In order to mitigate the potential negative impacts on aquatic fauna caused by the draining of impoundment reservoirs, surveys and management programs within numerous reservoirs in south-western Australia have been successfully undertaken over the past decade (e.g. Beatty et al. 2003; Molony et al. 2003; Molony et al. 2005; Morgan & Beatty 2004; Beatty et al. 2006; Klunzinger et al. 2011a). Freshwater mussels are important in maintaining functional freshwater ecosystems (Vaughn & Hakenkamp 2001) with a great capacity to filter plankton, algae and other particulate material from the water column, thus maintaining water clarity and quality. Their empty shells also provide refuge for other freshwater fauna, including juvenile Marron (Cherax cainii and Cherax tenuimanus), gobies (Pseudogobius olorum and Afurcagobius suppositus) and other freshwater crayfishes. They oxygenate the sediments through their burrowing habit, as evidenced by tracks that can be seen in the sediments. They are also a favoured food item by water birds (e.g. Porphyrio porphyrio, Threskiornis molucca, Threskiornis spinicollis), water rats (Hydromys chrysogaster), aquatic reptiles and Marron (see Vestjens 1972; Woollard et al. 1978; Shannon & Mendyk 2009; Klunzinger et al., unpublished data). Their sensitivity to environmental changes makes freshwater mussels important bio-indicators of freshwater ecosystem health (Ponder & Walker 2003). Most freshwater mussels have a life cycle intricately associated with freshwater fishes. The larvae of most Species have an obligate parasitic phase which generally requires a fish as a host for development and dispersal. A recent study by Klunzinger et al. (2012a) has revealed that glochidia (parasitic larvae) of Carter’s Freshwater Mussel (Westralunio carteri), the only freshwater mussel Species found in south-western Australia, undergo metamorphosis to the juvenile stage on most native freshwater fishes and Eastern Gambusia (Gambusia holbrooki), but not Goldfish (Carassius auratus) or Pearl Cichlid (Geophagus brasiliensis). Failure of these Feral Species to support the life cycle of W. carteri has serious implications for the Species in areas dominated by these Feral fishes. Glochidia were generally restricted to the fins of host fishes and virtually non-existent on the gills or body. The fishes which were exposed to glochidia in captivity showed no ill effect. Rather than being a threat to fish stocks, freshwater mussels improve and maintain water quality in freshwater rivers, lakes and other water bodies, which benefit freshwater fishes (Treasurer et al. 2006). Glochidia attachment to host fishes is a natural phenomenon and a necessary part of the mussel’s life history, which also functions as a dispersal method. In the host fishes which were experimentally exposed to glochidia of W. carteri, juvenile mussels (i.e. metamorphosed glochidia) detached from the fishes 21-27 days post-exposure (Klunzinger et al. 2012a). Westralunio carteri is a seasonal spawner, spawning in late winter (July); embryos are brooded until mid-spring/early-summer developing into mature glochidia, which are released on mucus strands in response to warming water temperatures and external stimuli during late August, peaking in October to November. Females are virtually spent by December (Klunzinger 2011; Klunzinger et al. 2011b, 2012a and unpublished data). Little is known about the juvenile stage of freshwater mussels due to their difficulty to locate in wild populations, but mortality is generally thought to be high from predation by other macroinvertebrates and they are quite sensitive to interstitial ammonia (Walker et al. 2001). Results of a PhD study have shown that W. carteri has undergone major population loss from salinity, climate change and human activity (Klunzinger et al., unpublished data), suggesting the Species is probably more threatened than previously believed to be and its current IUCN listing as ‘Least Concern’ is probably inappropriate. Significant mortalities of the Species resulting from water removal and dehydration within the Helena Pipehead Dam, necessitated the translocation of remaining live mussels (n = 1205) into a refuge pool downstream from the dam in April 2011 (Klunzinger et al. 2011a). The current study is the second to focus on freshwater mussels within reservoirs of the south-west.
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Aquatic macrofauna of Ellen Brook and the Brockman River: fresh water refuges in a salinised catchment
2020Co-Authors: Stephen J. Beatty, David L. Morgan, M.w. Klunzinger, Alan J. LymberyAbstract:The South West Coast Drainage Division houses a highly endemic assemblage of aquatic fauna. For example, the region’s freshwater fish (80% endemic) and crayfish (100% endemic) endemicity is unsurpassed within the continent. However, this fauna has been severely impacted by habitat change and introduced aquatic Species. Understanding the distribution and population viability of these aquatic organisms allows for the development and implementation of effective river action plans that can utilise these organisms as long‐term bioindicators of ecosystem health, but can also aid in the recognition of fauna that is in need of special protection. The Brockman River and Ellen Brook are both major tributaries of the Swan River. While the fishes of the Swan River and the Swan‐Canning estuary have been well studied, the freshwater fishes of its major tributaries have received far less research attention. This study aimed to collate previously existing data on the fishes in the freshwaters of Brockman River and Ellen Brook and survey additional sites in both systems in spring and summer 2009/2010 to gather information on the distribution and abundance of native freshwater and estuarine fishes, Feral fishes, native and Feral freshwater crayfishes, and a freshwater mussel. By undertaking this research, the study aimed to determine whether changes in the fish fauna had occurred and to set a basis for predicting future changes of the aquatic fauna. A total of 11342 fish, crayfish and turtles were captured during the survey of 10 sites on the Brockman River and seven sites on Ellen Brook in 2009/2010. Of these captures, 1707 (15.1%) were native freshwater fish, 4392 (38.7%) were native estuarine fish, 3323 (29.3%) were Feral freshwater fish, 421 (3.7%) were native freshwater crayfish, 1431 (12.6%) were native freshwater shrimp, 25 (0.2%) were a Feral freshwater crayfish, and 43 (0.4%) were the native Oblong Turtle (Chelodina oblonga). There were six Species of native endemic freshwater fishes recorded during the survey and from the collated existing information, including: the Western Minnow (Galaxias occidentalis), Western Pygmy Perch (Edelia vittata) and Nightfish (Bostockia porosa) which were all present in both the Brockman River and Ellen Brook catchments. The Freshwater Cobbler (Tandanus bostocki) and Western Mud Minnow (Galaxiella munda) were recorded only from the Brockman River and Ellen Brook catchment, respectively, the latter Species only being found in Lennard Brook. A further native endemic freshwater fish Species recorded within the Ellen Brook system is the Black‐stripe Minnow (Galaxiella nigrostriata), which is known from Melaleuca Swamp (Smith et al. 2002a, b) and very recently from Lake Chandala (McLure and Horwitz 2009). As these represent the only known populations of these two Species in the entire Swan‐Canning catchment (which is south‐western Australia’s largest), and that they are outlying populations compared to their next nearest populations, indicates that they require specific conservation consideration. There were two estuarine Species recorded in both systems: the Western Hardyhead (Leptatherina wallacei) and the Swan River Goby (Pseudogobius olorum) that have penetrated these systems. The Feral fish Species captured consisted of the Eastern Mosquitofish (Gambusia holbrooki) and the Goldfish (Carassius auratus). While the Eastern Mosquitofish was widespread, the Goldfish was restricted in distribution. The native freshwater crayfishes recorded were the Gilgie (Cherax quinquecarinatus), which was the most widespread Species and the Marron (Cherax cainii) that was much more restricted in distribution in both systems. The Feral Yabbie (Cherax destructor) was also recorded in the Ellen Brook catchment. Eradication of these established Feral Species would be very unlikely, however, there is the potential to control or remove the Goldfish given its apparent restricted distribution in both systems. The extreme rarity of Carter’s Freshwater Mussel (Westralunio carteri), the south‐west’s only endemic freshwater mussel, in both these systems is cause for concern. This Species is likely to play an important role in ecosystem health and its larval phase is reliant on fish hosts. Although the life‐cycle is poorly understood, but is under current investigation by one of the authors, this study implies that it may have undergone a large range reduction in Ellen Brook, the Brockman River and other salt‐affected systems in the region. Further, if the range reductions of fishes that are hosts to the larval stage of the mussel have occurred, then this may have led to a concomitant decline in mussel distribution.
David L. Morgan - One of the best experts on this subject based on the ideXlab platform.
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Margaret River Fishway
2020Co-Authors: David L. Morgan, Stephen J. BeattyAbstract:In order to enhance the migrations of fish Species in the Margaret River, the Margaret River Regional Environment Centre, in conjunction with the Department of Environment, constructed a rock ramp fishway at the Margaret River Weir (Apex Weir) between March and April 2003. Morgan and Beatty (2003) surveyed the fish fauna of the river during March 2003, capturing 9206 fish from five native Species, one Feral Species and the pouched lamprey (Geotria australis) (see Plate 1). All of the native fishes of the river are endemic to south-western Australia while the Feral Species is the mosquitofish (Gambusia holbrooki). The only other records of fish from the river are those recorded by Morgan et al. (1998) and there are also a few records in the Western Australian Museum. Large numbers of native fishes were known to be impeded by the town weir on their upstream migration during winter and spring. These native fishes included the western minnow (Galaxias occidentalis), western pygmy perch (Edelia vittata) and nightfish (Bostockia porosa). Furthermore, adult lampreys were often observed negotiating the weirs on Margaret River with the occasional dead animal also observed. The reservoir above the Margaret River Weir had the highest abundance of the Feral mosquitofish with this section of the river also containing western minnows, nightfish and western pygmy perch, and beds for larval lampreys (ammocoetes) (Morgan and Beatty 2003). It was thus deemed appropriate that the construction of a fishway on the Margaret River would be beneficial to fish and lamprey migrations in the Margaret River.
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Little fish under threat in a big state: south-western Western Australia’s endemic freshwater fishes
2020Co-Authors: Stephen J. Beatty, David L. MorganAbstract:Widespread habitat alterations and impacts of Feral Species have led to range reductions and population declines of south‐western Australia’s highly endemic freshwater fishes. Some Species have been lost from systems and/or are restricted to specific habitats within catchments. Habitat alterations primarily due to salinisation, water extraction and river regulation have compromised many populations. Recent studies on distributions, habitat associations, salinity tolerances, migratory patterns and fishway utilisation has greatly increased our understanding of these key threats and has enabled us to identify populations at greatest risk and to begin to predict future viabilities. This research is currently being used to prioritise populations and develop strategies to help ensure their ongoing sustainability.
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Fish fauna of the Vasse River and the colonisation by Feral goldfish (Carassius auratus)
2020Co-Authors: David L. Morgan, Stephen J. BeattyAbstract:During December 2003 and March 2004 a total of 7895 fish from nine Species were captured during a survey of the Vasse River, including two sites in the Vasse River Diversion Drain. Of the fish captured, four were native freshwater fishes that are endemic to the south-west, three were native estuarine Species and two were introduced fishes. Two estuarine Species dominated the native catches with the western hardyhead (Leptatherina wallacei) being captured at the most downstream sites and the Swan River goby (Pseudogobius olorum) being captured throughout the river aside from the upper-most headwater site. The endemic western pygmy perch (Edelia vittata) was also widely distributed in the river, however, it was captured in relatively low numbers aside from immediately downstream of the Diversion Drain at a site with more complex in-stream and riparian habitat. The western minnow (Galaxias occidentalis) and nightfish (Bostockia porosa) were only captured in relatively low numbers at two sites each in the lower Vasse River. This study also captured the rare mud minnow (Galaxiella munda) at the headwater site, which is the first record of this Species in the Vasse River. The Vasse River is generally heavily modified and two introduced Feral Species, the mosquitofish (Gambusia holbrooki) and goldfish (Carassius auratus) have become established and accounted for over 60% of all fish captures. These Species were particularly dominant in more degraded reaches of the river, such as the Diversion Drain and the lower Vasse River. The goldfish were captured in the lower Vasse River, between the Diversion Drain and immediately below the Old Butter Factory slot-boards. This stretch of the river has essentially become a heavily silted, stagnant pool due to the restriction of flow from the Diversion Drain and the presence of slot-boards, which together prevent adequate flushing of the system and that is likely to have facilitated the establishment of the Feral Species, as well as exacerbating algal blooms. It is suggested that the introduction of goldfish into the Vasse River is relatively recent and the dominance of juveniles born in October last year will result in a rapid increase in the population in the next few years. Growth rates of goldfish in the Vasse River far exceed those reported elsewhere with individuals attaining lengths of over 180 mm TL at the end of their first year, the age at which they also mature. Goldfish are known to be vectors for disease introduction, may prey on native fish and their eggs and larvae, reduce aquatic plant biomass and re-suspend nutrients further fuelling algal blooms. Furthermore, recent studies have demonstrated that significant growth of cyanobacteria is stimulated by the passage through goldfish intestines. Goldfish, which attained lengths of over 40 cm in the Vasse River, therefore have the potential to contribute to algal blooms. It is recommended that flushing of the river could occur by removal of the slot-boards at the Old Butter Factory and diverting flows from the Diversion Drain back into the river, thus attempting to return environmental flows to a more natural regime. Riparian vegetation should also continue to occur in this stretch of the River with estuarine Species able to tolerate the higher salinities expected to occur as the River returns to a more natural, estuarine system. A goldfish eradication program should be implemented in the lower Vasse River. This program would also provide an excellent opportunity to gain further information on their biology and ecological impact in the system, particularly with regard to their role in algal blooms. An education program should also be implemented outlining the problems caused by releasing aquarium fish into wild aquatic systems.
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Aquatic macrofauna of Ellen Brook and the Brockman River: fresh water refuges in a salinised catchment
2020Co-Authors: Stephen J. Beatty, David L. Morgan, M.w. Klunzinger, Alan J. LymberyAbstract:The South West Coast Drainage Division houses a highly endemic assemblage of aquatic fauna. For example, the region’s freshwater fish (80% endemic) and crayfish (100% endemic) endemicity is unsurpassed within the continent. However, this fauna has been severely impacted by habitat change and introduced aquatic Species. Understanding the distribution and population viability of these aquatic organisms allows for the development and implementation of effective river action plans that can utilise these organisms as long‐term bioindicators of ecosystem health, but can also aid in the recognition of fauna that is in need of special protection. The Brockman River and Ellen Brook are both major tributaries of the Swan River. While the fishes of the Swan River and the Swan‐Canning estuary have been well studied, the freshwater fishes of its major tributaries have received far less research attention. This study aimed to collate previously existing data on the fishes in the freshwaters of Brockman River and Ellen Brook and survey additional sites in both systems in spring and summer 2009/2010 to gather information on the distribution and abundance of native freshwater and estuarine fishes, Feral fishes, native and Feral freshwater crayfishes, and a freshwater mussel. By undertaking this research, the study aimed to determine whether changes in the fish fauna had occurred and to set a basis for predicting future changes of the aquatic fauna. A total of 11342 fish, crayfish and turtles were captured during the survey of 10 sites on the Brockman River and seven sites on Ellen Brook in 2009/2010. Of these captures, 1707 (15.1%) were native freshwater fish, 4392 (38.7%) were native estuarine fish, 3323 (29.3%) were Feral freshwater fish, 421 (3.7%) were native freshwater crayfish, 1431 (12.6%) were native freshwater shrimp, 25 (0.2%) were a Feral freshwater crayfish, and 43 (0.4%) were the native Oblong Turtle (Chelodina oblonga). There were six Species of native endemic freshwater fishes recorded during the survey and from the collated existing information, including: the Western Minnow (Galaxias occidentalis), Western Pygmy Perch (Edelia vittata) and Nightfish (Bostockia porosa) which were all present in both the Brockman River and Ellen Brook catchments. The Freshwater Cobbler (Tandanus bostocki) and Western Mud Minnow (Galaxiella munda) were recorded only from the Brockman River and Ellen Brook catchment, respectively, the latter Species only being found in Lennard Brook. A further native endemic freshwater fish Species recorded within the Ellen Brook system is the Black‐stripe Minnow (Galaxiella nigrostriata), which is known from Melaleuca Swamp (Smith et al. 2002a, b) and very recently from Lake Chandala (McLure and Horwitz 2009). As these represent the only known populations of these two Species in the entire Swan‐Canning catchment (which is south‐western Australia’s largest), and that they are outlying populations compared to their next nearest populations, indicates that they require specific conservation consideration. There were two estuarine Species recorded in both systems: the Western Hardyhead (Leptatherina wallacei) and the Swan River Goby (Pseudogobius olorum) that have penetrated these systems. The Feral fish Species captured consisted of the Eastern Mosquitofish (Gambusia holbrooki) and the Goldfish (Carassius auratus). While the Eastern Mosquitofish was widespread, the Goldfish was restricted in distribution. The native freshwater crayfishes recorded were the Gilgie (Cherax quinquecarinatus), which was the most widespread Species and the Marron (Cherax cainii) that was much more restricted in distribution in both systems. The Feral Yabbie (Cherax destructor) was also recorded in the Ellen Brook catchment. Eradication of these established Feral Species would be very unlikely, however, there is the potential to control or remove the Goldfish given its apparent restricted distribution in both systems. The extreme rarity of Carter’s Freshwater Mussel (Westralunio carteri), the south‐west’s only endemic freshwater mussel, in both these systems is cause for concern. This Species is likely to play an important role in ecosystem health and its larval phase is reliant on fish hosts. Although the life‐cycle is poorly understood, but is under current investigation by one of the authors, this study implies that it may have undergone a large range reduction in Ellen Brook, the Brockman River and other salt‐affected systems in the region. Further, if the range reductions of fishes that are hosts to the larval stage of the mussel have occurred, then this may have led to a concomitant decline in mussel distribution.
John R Meier - One of the best experts on this subject based on the ideXlab platform.
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feasibility of micronucleus methods for monitoring genetic damage in two Feral Species of small mammals
Environmental and Molecular Mutagenesis, 1999Co-Authors: John R Meier, Paul Wernsing, Joni TorsellaAbstract:Peromyscus leucopus (white-footed mouse) and Cryptotis parva (least shrew) possess desirable attributes for biomonitoring contamination of terrestrial ecosystems, but few studies have examined the potential use of these Species for monitoring exposure to genotoxic contaminants. The susceptibility of laboratory-reared C. parva, P. leucopus, and Mus musculus (house mouse, strain CD-1) to micronucleus (MN) induction by known clastogens was evaluated. Animals were exposed for 24 hr to methyl methanesulfonate (MMS; 12.5, 25, and 50 mg/kg), 4-nitroquinoline 1-oxide (4-NQO; 7.5, 15, and 30 mg/kg), or mercuric chloride (HgCl 2 ; 6, 12, and 24 mg/kg). Both MMS and 4-NQO induced dose-related increases in micronucleated polychromatic erythrocytes (MNPCE) in all three Species, whereas HgCl 2 induced a weak response only in P. leucopus. P. leucopus and C. parva were more sensitive than M. musculus to MMS. Similar micronucleus responses to 4-NQO were seen in each of the Species. The feasibility of using blood for MN assessment was evaluated by comparing MN frequencies in bone marrow (BM) PCE, and blood PCE and normochromatic erythrocytes (NCE) in untreated animals, and following daily treatment for 1, 2, 3, and 10 days with 0.4 mg/kg triethylenemelamine (TEM). The results indicated that micronucleated erythrocytes were removed from the circulating blood in P. leucopus, but not in C. parva. Measurement of BM and blood MN levels appears feasible for monitoring exposure to genotoxic agents in C. parva and P. leucopus, and for distinguishing between acute and chronic exposure in C. parva.
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Comparative sensitivity of small mammals to micronucleus induction in bone marrow cells by clastogenic compounds
1995Co-Authors: John R Meier, Paul Wernsing, F.b. Daniel, Joni TorsellaAbstract:The bone marrow micronucleus assay is the most widely used method for detecting genetic damage in vivo, but this assay has received little attention for its possible application to biomonitoring terrestrial environments. The present study compared the responsiveness of three small mammalian Species, Cryptotus parva (least shrew), Peromyscus leucopus (white-footed mouse), and strain CD-1 Mus musculus (house mouse), to the clastogen, methylmethanesulfonate (MMS). Five animals of each sex of each Species were exposed for 24 h to four concentrations of MMS ranging from 0 to 50 mg/kg. Bone marrow cells were flushed from the femurs, and smears were stained with acridine orange and examined using fluorescence microscopy. The slides were scored for evidence of acute bone marrow toxicity (polychromatic to normochromatic erythrocyte ratio, PCE:NCE) and frequency of micronucleated PCE. PCE:NCE was depressed at 50 mg/kg in P. leucopus, but not in the other Species. Dose-related increases in micronucleated PCE were observed in all three Species, with males being more sensitive for P. leucopus and M. musculus, and females being more sensitive for C. parva. For both sexes, the two Feral Species, P. leucopus and C. parva, were more sensitive than M. musculus. These studies demonstrate the successful application of themore » bone marrow micronucleus assay to Species other than standard laboratory strains of mice. The results also demonstrate heretofore unrecognized Species differences in responsiveness.« less
Luis Zambrano - One of the best experts on this subject based on the ideXlab platform.
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Raining Feral cats and dogs? Implications for the conservation of medium-sized wild mammals in an urban protected area
Urban Ecosystems, 2020Co-Authors: Helí Coronel-arellano, Maya Rocha-ortega, Fernando Gual-sill, Enrique Martínez-meyer, Agueda Karina Ramos-rendón, Marcela González-negrete, Guillermo Gil-alarcón, Luis ZambranoAbstract:Mammals are one of the most negatively affected groups by urbanization, nevertheless, urban reserves can help their conservation. The study of wildlife within the reserves is important for the persistence of these populations, but stressors factors as Feral fauna might endanger the conservation of wildlife. Therefore, our objective was to analyze the patterns of temporal and spatial activity of wild and Feral mammals within the San Angel Pedregal Ecological Reserve, UNAM, Mexico City, using trap cameras. We found five Species of wild mammals and two Feral ones. All mammals were primarily nocturnal, except for the Rock Squirrel which changes their behavior in comparison with individuals in natural habitats. All wildlife Species showed a high temporal overlap of activity with Feral fauna particularly, Rock Squirrel, Eastern Cottontail, and Gray Fox. The analysis of spatial co-occurrence showed that the probability of an encounter between Species at a certain point of the reservation is random. Although, due to the reduced area of the reserve, Species may overlap spatially. In general, our results indicate that Feral fauna has a high overlap of activity with wildlife, however, the studied reserve protects wildlife populations. Therefore, to reduce this overlap, we recommend creating a dog and cat management program for urban protected areas and surrounding areas. Particularly in REPSA, we encourage to continue with the control program of Feral Species in the long term and change the management of waste within the UNAM.