David Lloyd Morgan

David Lloyd Morgan
Murdoch University · Freshwater Fish Group & Fish Health Unit, Centre for Sustainable Aquatic Ecosystems (Harry Butler Institute)

BSc(Hons), PhD

About

274
Publications
66,530
Reads
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3,954
Citations
Citations since 2016
85 Research Items
2211 Citations
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20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Introduction
The main focus of my research relates to threatened fishes (teleosts and elasmobranchs), particularly in Western Australia. I also study alien fishes and their impacts to native fauna. Much of my research revolves around the ecology of fish and how they use their habitats.
Additional affiliations
January 2016 - present
Murdoch University
Position
  • Professor (Associate)
January 1992 - April 2015
Murdoch University
Position
  • Senior Research Leader

Publications

Publications (274)
Article
Full-text available
Knowledge of how an animal uses its habitat is a fundamental component of effective conservation strategies. The Critically Endangered largetooth sawfish Pristis pristis uses rivers and their estuaries as nursery habitats, where it is likely to be exposed to elevated pressures from anthropogenic-induced stresses including fishing (e.g. bycatch, dir...
Article
Full-text available
The largest of the sawfishes is the Critically Endangered green sawfish Pristis zijsron, a species believed to have undergone a major decline (38%) in extent of occurrence. Conservation efforts are hampered by the lack of information on the habitat requirements of this species. We used passive acoustic telemetry to document the movement patterns of...
Article
Full-text available
The freshwater sawfish (Pristis pristis) was recently listed as the most Evolutionarily Distinct and Globally Endangered (EDGE) animal. The Fitzroy River in the remote Kimberley region of north-western Australia represents a significant stronghold for the species, which uses the freshwater reaches of the river as a nursery. There is also mounting p...
Article
• Sawfishes (Family: Pristidae) are one of the most imperilled fish families worldwide. There is an increasingly urgent need to better understand the biology, ecology, and population status of the five sawfish species to develop more effective conservation measures. The dwarf sawfish, Pristis clavata, is one of the least researched members of the p...
Article
Full-text available
Freshwater mussels are important functional components of aquatic ecosystems. Westralunio carteri is a threatened freshwater mussel species, endemic to south-western Australia, which has suffered a recent, dramatic decline in range. The density, size structure and distribution of adult mussels of this species within river reaches were investigated...
Chapter
This chapter provides a general discussion of ethical considerations and procedures relating to the capture and handling of freshwater animals, including welfare considerations for the study species and non-target species.
Article
Full-text available
A new microbothriid monogenean Dermopristis pterophilus n. sp. is described from the skin of the Critically Endangered green sawfish Pristis zijsron Bleeker, 1851 in the Ashburton River delta, northern Western Australia. Analyses of the 28S ribosomal DNA marker and the molecular barcoding markers Histone 3 and Elongation Factor 1 α confirmed positi...
Article
• Gambusia holbrooki is arguably the most widely introduced and ecologically damaging freshwater fish in the world. Although aspects of its aggressive behaviour have been studied in lentic environments and ex situ experiments, the physical damage to native freshwater fishes in riverine systems caused by this behaviour remains relatively unknown. •...
Article
The Asian fish tapeworm ( Schyzocotyle acheilognathi ) is an important fish parasite with a wide host range that infects over 300 species of fish worldwide. Schyzocotyle acheilognathi has been reported from eastern coastal areas of Australia, but has not been previously reported in Western Australia (WA). During a control program for invasive fresh...
Article
Gambusia holbrooki is one of the world's most environmentally damaging introduced species, being notoriously difficult to control once established. A composite double-winged fyke net comprising four vertically stacked compartments was developed to determine the potential to control Gambusia holbrooki, while reducing negative interactions of this ag...
Article
Full-text available
Reduced streamflow because of climate change presents a major threat to aquatic biodiversity in arid, semi-arid and Mediterranean climatic regions. Freshwater mussels are particularly sensitive to this threat, because of their sedentary nature and limited mobility as juveniles or adults. The freshwater mussel Westralunio carteri, which is endemic t...
Article
Symbiotic relationships between fishes and other organisms are not always easily defined, and three-way symbiotic relationships are rarely reported. Here we examine the relationship between the endangered whale shark, echeneids (remoras and sharksuckers) and a symbiotic copepod. Through their symbiosis with whale sharks, sharksuckers gain one food...
Preprint
Full-text available
PurposeThe Asian fish tapeworm ( Schyzocotyle acheilognathi ) is an important fish parasite with a wide host range that infects over 300 species of fish worldwide. Schyzocotyle acheilognathi has been reported from eastern coastal areas of Australia, but has not been previously reported in Western Australia (WA). Methods During a control program for...
Article
Full-text available
The relationship between growth and sexual maturation is central to understanding the dynamics of animal populations which exhibit indeterminate growth. In sequential hermaphrodites, which undergo post-maturation sex change, the size and age at which sex change occurs directly affects reproductive output and hence population productivity. However,...
Article
The increase in severity and occurrence of drought from environmental change poses a significant threat to freshwater ecosystems. However, many of the mechanisms by which periodic drought affects aquatic animals are poorly understood. Here we integrated physical, physiological, and behavioural measurements made in the field over a twelve-year perio...
Article
Understanding how the movement and habitat use of fishes are influenced by flow regimes is important in sustainably managing river ecosystems, particularly in regions undergoing drying due to climate change. Here, we aimed to determine how the movement of a freshwater fish from refuge pools is influenced by discharge and environmental variables in...
Article
With recent advances in sequencing technology, genomic data are changing how important conservation management decisions are made. Applications such as Close‐Kin Mark‐Recapture demand large amounts of data to estimate population size and structure, and their full potential can only be realised through ongoing improvements in genotyping strategies....
Article
Full-text available
Environments where extreme temperatures and low productivity occur introduce energetically challenging circumstances that may be exacerbated by climate change. Despite the strong link between metabolism and temperature in ectotherms, there is a paucity of data regarding how the metabolic ecology of species affects growth and fitness under such circ...
Article
• 1. Small‐bodied freshwater fishes are commonly overlooked in threatened species management despite being highly imperilled. Before this study, the newly described little pygmy perch (Nannoperca pygmaea) was known from only 0.06 km² of habitat in a single catchment in south‐western Australia and a lack of knowledge prevented an understanding of it...
Article
This study developed a portable, low-cost field respirometer for measuring oxygen consumption rates of large-bodied fishes. The respirometer performed well in laboratory tests and was used to measure the oxygen consumption rates ( M ˙ O2 ) of bull sharks Carcharhinus leucas (mean: 249.21 ± 58.10 mg O2 kg-1 h-1 at 27.05°C). Interspecific compari...
Article
Full-text available
Globally, freshwater fishes are declining at an alarming rate. Despite much evidence of catastrophic declines, few Australian species are listed as threatened under national legislation. We aim to help redress this by identifying the Australian freshwater fishes that are in the most immediate risk of extinction. For 22 freshwater fishes (identified...
Article
As Nannorperca pygmaea was only recently described (Morgan et al. 2013), the species had not been previously assessed. Comprehensive surveys since that period have allowed a detailed assessment of the AOO (40 km2) and EOO (<5000 km2) as well as estimates of population abundance in the type locality and it is found from 4 sites/locations (Beatty et...
Article
This species is assessed as Endangered (EN) due to small AOO, limited locations (1) and continuing decline in distribution, sub populations and habitat. Nannatherina balstoni has not been assessed since it was listed as DD in 1996. Only limited information was provided in that review. Since that time, the ecology and distribution has been mapped (M...
Article
This species is assessed as Least Concern. It is widespread and common in south-eastern Australia. Populations in Western Australian have previously declined and are now extremely restricted and isolated, but currently considered stable. Loss of the Western Australian subpopulations would result in a dramatic decline in the extent of occurrence (EO...
Article
This species was previously listed as Near Threatened by Wager (1996); data was lacking at that time. Ogston et al. (2016) demonstrated a recent (since 2000) climate change driven decline in EOO of 57% and a decline in AOO of 58% compared to historical records identified in Morgan et al. (1998). This species is now assessed as Endangered as a resul...
Article
This species was previously assessed as Near Threatened (Wager 1996) but limited information was available at that time, with distribution studies commencing around that time and recent evidence demonstrating serious declines in the populations (see Morgan et al. 1998, 2000; Ogston et al. 2016). This species is now assessed as Endangered due to its...
Article
This Australian species is known only from the Pentecost River, Western Australia to the Daly River, Northern Territory. There are very few records from the Kimberley, mostly in the Ord River.
Article
This species is endemic to the coastal rivers of the Pilbara Province of Western Australia (Allen et al. 2002, Morgan et al. 2014). It has been found in the Greenough, Hutt, Murchison, Wooramel, Gascoyne and De Grey rivers, but is absent from numerous rivers between the Gascoyne and De Grey rivers (Morgan and Gill 2004).
Article
This species is widespread, occurring in coastal drainages in northern and eastern Australia, and in southern central Papua New Guinea (Pusey et al. 2004). It is found from the Chapman River in Western Australia north throughout the Pilbara (Morgan and Gill 2004), to the Towamba River in southern New South Wales, as well as on Fraser, Moreton, Brib...
Article
This species occurs in the Kimberley Region of Western Australia where it is widespread within the Fitzroy River catchment, and also occurs in the Calder and Isdell Rivers (Morgan et al. 2011). This species is known to occupy several catchments in the Kimberley (Shelley et al. 2018).
Article
This species is found across eastern and northern Australia from the Northern Territory east and south to the Murray-Darling River. The species complex comprises three clades which probably present three discrete species (Unmack and Dowling 2010).
Article
Kimberleyeleotris hutchinsi occurs in the Mitchell River in the northern Kimberley Region, Western Australia where it is one of the most restricted freshwater fish species in Australia. It is known only from the Mitchell River system immediately upstream of Mitchell Falls and downstream of Mertens Falls where the species was first collected by Hutc...
Article
This species is considered locally common but occurs in highly restricted distributions. It is known only from two small tributaries of Prince Regent River and at King's Cascade, in the Western Kimberly region of Western Australia (Allen 1975, 1978; Morgan et al. 2011). This species is typically found in schools of up to 50 or more individuals in f...
Article
This species is endemic to the south-west of Western Australia in coastal drainages from Waychinicup River east of Albany to the Arrowsmith River 300 km north of Perth. It is found in most river systems throughout the region, as well as lakes along the south coast (Morgan et al. 1998, 2011). This is considered one of the most common and widespread...
Article
The Fortescue Grunter is assessed as Endangered (EN). It is found in three river basins but is only reasonably common in one where it is restricted to deep pools. There have been recent invasions of alien species within its range (see Morgan et al. 2014) and the catchment has multiple active mines which cause continuing decline in habitat quality.
Article
The species is assessed as Near Threatened. It has a small AOO with continuing decline in habitat quality. This species is endemic to Western Australia's Southwestern Province, and is found in the coastal region between the Moore River (Gingin) in the north and the Frankland River (Walpole) on the south coast (Allen et al. 2002, Morgan et al. 2011...
Article
This species is essentially endemic to the Drysdale River and one small tributary of each of the Morgan River (King Edward River), the King George River and the Durack River in the Kimberly region of far northern Western Australia (Hutchins 1977, Allen 1978, Morgan 2010, Morgan et al. 2011, ALA). Despite its restricted distribution, this species is...
Article
This species is widely distributed across northern Australia and southern New Guinea. (Allen et al. 2002). In Australia it occurs from the Fitzroy River in the Kimberley region across northern and eastern Australia, down to northern New South Wales (Morgan et al. 2004, 2011, Pusey et al. 2017). It has a semi-continuous distribution through northern...
Article
This species occurs in upper reaches of Barnett River and Manning Creek in the Fitzroy River catchment in Western Australia (Hoese and Allen 1983, Morgan et al. 2004, Shelley and Le Feuvre 2018). The species is endemic to the Fitzroy River catchment (Morgan et al. 2004). The species is most abundant in gorges below waters at Manning Creek and Barne...
Article
This species is endemic to the Kimberley Region of Western Australia, where it is restricted to the south-western corner of the region (Morgan et al. 2011). It is widespread throughout the Fitzroy River (Morgan et al. 2004, 2011), and has also been recorded in the Meda, May, Isdell, Charnley, Calder, Sale, and Glenelg Rivers (Allen and Gomon 2018).
Article
Hypseleotris ejuncida occurs in a small section of Prince Regent River in the Kimberley region of northern Western Australia within Gundarara Creek approximately 2 km upstream of the confluence with the Prince Regent River where it was collected in 1974 (Hoese and Allen 1983). The species has also been recorded in an unnamed tributary of the lower...
Article
Full-text available
Temperature is one of the most influential drivers of physiological performance and behaviour in ectotherms, determining how these animals relate to their ecosystems and their ability to succeed in particular habitats. Here, we analysed the largest set of acceleration data compiled to date for elasmobranchs to examine the relationship between volit...
Article
Sampling fish communities in tropical estuaries is inherently challenging due to poor visibility and the potential presence of dangerous fauna. We present two strategies for improving the identification of fishes in a turbid tropical estuary using video. The first was to attract species close to the camera by using two different bait types compared...
Article
Despite its social and economic benefits, the ornamental trade has become a major source of non-native fish introductions into freshwater ecosystems. However, the ornamental trade as a vector for introductions of non-native freshwater fishes is not well defined. We developed a framework incorporating elements of biological invasion processes and a...
Article
Full-text available
Diadromy is a form of migration where aquatic organisms undergo regular movements between fresh and marine waters for the purposes of feeding and reproduction. Despite having arisen in independent lineages of fish, gastropod molluscs and crustaceans, the evolutionary drivers of diadromous migration remain contentious. We test a key aspect of the ‘p...
Article
Understanding the modalities of aquatic species introductions is important in predicting and preventing new invasions. Australia’s Pilbara Province is an arid region with no naturally occurring freshwater crayfishes.We assessed the population demographics and reproductive potential of redclaw crayfish (Cherax quadricarinatus) in Lake Poongkaliyarra...
Article
Almost one third of all freshwater crayfishes are threatened with extinction. The factors influencing the distribution of freshwater crayfishes in lentic systems are poorly understood, hampering the conservation and enhancement of those populations. Cherax cainii is the third largest freshwater crayfish in the world and is endemic to south‐western...
Article
This species is assessed as Endangered, due to the small AOO, small number of locations, and continuing decline in AOO and habitat quality. Hypseleotris aurea is endemic to two rivers in Western Australia's Pilbara Province (Allen et al. 2002, Morgan and Gill 2004, Morgan et al 2014). Within the Murchison River and Gascoyne River, despite the EOO...
Article
Full-text available
Estuarine storm surge barriers are designed to prevent the flooding of human-developed landscapes. While such barriers may have a range of ecological impacts, including the fragmentation of aquatic habitats and the alteration of water quality, their impact on obligate estuarine fishes is largely unknown. The sparid, Acanthopagrus butcheri, was used...
Article
Full-text available
threatened aquatic fauna of Margaret River region
Article
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Aim Changing preferences regarding which species humans have transported to new regions can have major consequences for the potential distribution of alien taxa, but the mechanisms shaping these patterns are poorly understood. We assessed the extent to which changes in human preferences for transporting and introducing alien freshwater fishes have...
Book
Full-text available
The Kimberley region in north-western Australia is world renowned for its rugged natural beauty, remoteness, waterfalls, and Aboriginal culture. It is home to a rich array of animals and plants, including a large number found nowhere else on Earth. The fish fauna is no exception, among which are species that are culturally important such as the ico...
Article
Full-text available
The whale shark is an ideal flagship species for citizen science projects because of its charismatic nature, its size, and the associated ecotourism ventures focusing on the species at numerous coastal aggregation sites. An online database of whale shark encounters, identifying individuals on the basis of their unique skin patterning, captured almo...
Article
Following the complete eradication of the alien piscivorous perch Perca fluviatilis from a potable reservoir, the abundance of the endemic western minnow Galaxias occidentalis, which was previously undetectable prior to the initial eradication event, increased dramatically. The study reveals the potential of reservoirs to act as ecological refuges...
Article
Full-text available
The taxonomy of critically endangered and geographically isolated populations of the Spotted Galaxias (Galaxias truttaceus) from either side of the Australian continent has only recently been resolved with those in Mediterranean-climatic Western Australia considered to be an evolutionary significant unit . Ontogenetic changes in gross morphology, p...
Article
Full-text available
Margaret River and the Cape to Cape region in the extreme south-western tip of Australia are located between Cape Naturaliste in the north and Cape Leeuwin in the south and encompass all intervening catchments that drain westward to the Indian Ocean. The region has a Mediterranean climate and houses 13 native, obligate freshwater macrofauna species...
Article
Whale sharks Rhincodon typus were monitored via acoustic transmitters at the northern end of Western Australia's Ningaloo Marine Park to establish the extent to which the species inhabits the region beyond the whale-shark ecotourism industry season, which usually extends from March to August in each year. Despite the vast majority (c. 98%) of photo...
Poster
Full-text available
Poster presenting the findings of a risk-based targeted survey for E. ictaluri in wild fishes in northern Australia.
Article
Goldfish (Carassius auratus) was one of the first fishes to be domesticated and has been widely introduced across the globe, but is now considered one of the world's worst invasive aquatic species. Surprisingly, there is a dearth of information on its spatial and temporal movement patterns, which hampers the development of effective control program...
Article
The bacterium Edwardsiella ictaluri is considered to be one of the most significant pathogens of farmed catfish in the United States of America and has also caused mortalities in farmed and wild fishes in many other parts of the world. E. ictaluri is not believed to be present in wild fish populations in Australia, although it has previously been d...
Article
Full-text available
Northern Australia has been identified as the last stronghold for the dwarf sawfish Pristis clavata, green sawfish P. zijsron, and largetooth sawfish P. pristis, making these populations key in global conservation efforts for each species. This research assesses the levels of genetic diversity in these 3 sawfishes in Australian waters, testing for...
Article
Full-text available
This research demonstrates how population structure differs in elasmobranchs with different patterns of habitat use. Population structure was assessed using data at microsatellite loci in three species of Pristis sawfishes in northern Australian waters. Statistically significant population structure was found in each of P. clavata and P. zijsron, w...
Article
Full-text available
Circadian rhythms occur widely amongst living organisms, often in response to diel changes in environmental conditions. In aquatic animals, circadian activity is often synchronised with diel changes in the depths individuals occupy and may be related to predator–prey interactions, where the circadian rhythm is determined by ambient light levels, or...
Article
Detailed computational fluid dynamics simulations for the rostrum of three species of sawfish (Pristidae) revealed that negligible turbulent flow is generated from all rostra during lateral swipe prey manipulation and swimming. These results suggest that sawfishes are effective stealth hunters that may not be detected by their teleost prey's latera...