Paul Humphries

Paul Humphries
Charles Sturt University · School of Environmental Sciences

PhD

About

80
Publications
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Introduction
I am a fish and river ecologist, specializing in early life history, and increasingly including historical ecology of rivers and floodplains in my research.

Publications

Publications (80)
Article
Full-text available
Lateral Hydrological Connectivity (LHC) has been extensively fragmented in river–floodplain ecosystems of the world. Uncertainties about how LHC affects fishes are great, impeding the design of effective rehabilitation strategies. Existing conceptual frameworks do not provide sufficient mechanistic detail to support the novel decision problems rive...
Article
• Studies in the Northern Hemisphere have shown that mussels play important roles as benthic‐pelagic couplers in freshwater systems, transferring filtered material, nutrients, and energy from the water column to sediments, through biodeposition and excretion. However, we know little of the functional roles of species of the Southern Hemisphere Hyri...
Article
The size and intensity of bushfires during the 2019‐2020 Australian season has been unprecedented (Nolan et al., 2020). The fires in south‐eastern Australia were extraordinary in terms of the land area burnt (7.2 million hectares; Figure 1); four times that of the 2019 Brazilian Amazon and 1.8 times the 2017 United States’ fires (Bladon, 2018). The...
Article
Most fish recruitment models consider only one or a few drivers in isolation, rarely include species’ traits and have limited relevance to riverine environments. Despite their diversity, riverine fishes share sufficient characteristics that should enable predictions of recruitment. Here we synthesize the essential components of fish recruitment hyp...
Article
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The Australian Government is considering Cyprinid herpesvirus 3 (CyHV-3) for biocontrol of invasive common carp (Cyprinus carpio L.). We review the evidence-base for its potential ecological risks, benefits and effectiveness. Lower carp abundance may boost native fish biomass and improve water clarity, but there is little evidence available to sugg...
Article
The biomass of organisms of different sizes is increasingly being used to explore macroscale variation in food-web and community structure. Here we examine how invasive species and river flow regulation affect native fish biomass and fish community log10 biomass – body mass scaling relationships in Australia’s largest river system, the Murray–Darli...
Article
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Subfossil chironomid head capsules have been used extensively as proxies to characterise past environmental conditions of waterbodies. To date, their potential to distinguish between temporary and permanent waterbodies has not been determined. This study set out to assess if subfossil chironomid head capsules could be used to distinguish between te...
Article
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The special issue brings together selected contributions from the 39th Annual Larval Fish Conference hosted by the University of Vienna, Austria, and presents the latest research and understanding of dispersal patterns and processes of early life stages of fishes of various aquatic environments around the world (open ocean, coastal areas, estuaries...
Article
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The serial discontinuity concept (SDC) proposes that hypolimnetic-releasing impoundments cause major disruptions to the naturally occurring physical, chemical and biological gradients of rivers but that this impact diminishes with distance downstream. Such a gradient in discharge, flow velocity and temperature regime occurs below a large hypolimnet...
Article
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Fish species that have no commercial or recreational value are often overlooked in conservation management, despite serious threats to their long-term future. This can be termed the 'small threatened freshwater fishes' paradigm. Population viability analysis (PVA) is a useful technique to assess threatened species and conservation management option...
Article
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Large-scale invasive species control initiatives are motivated by laudable desires for native species recovery and economic benefits, but they are not without risk. Management interventions and policies should include evidence-based risk–benefit assessment and mitigation planning.
Article
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We investigated the mode (active vs. passive) of larval downstream dispersal and it´s influencing factors in the nase carp (Chondrostoma nasus). Marked larvae (early and later stages) together with equivalent numbers of passive particles were released in the main channel of the River Danube (Austria) at different flow- (low-flow, high-flow) and cur...
Article
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en Small body size is generally correlated with r‐selected life‐history traits, including early maturation, short‐generation times, and rapid growth rates, that result in high population turnover and a reduced risk of extinction. Unlike other classes of vertebrates, however, small freshwater fishes appear to have an equal or greater risk of extinct...
Article
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Current-mediated downstream dispersal by the early developmental stages of fish in rivers is a common phenomenon. Knowledge of patterns and processes in the dispersal, or ‘drift’, of young fishes provides important information on spawning location and spawning success, habitat use, movement paths and flow-ecology relationships more generally, all o...
Article
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Global ecosystems have shifted from historical conditions, but it is unclear from what baselines change should be assessed. Scientists and managers have increasingly accepted the impossibility of returning ecosystems to a “pristine” state; however, historical conditions remain the cornerstone for restoration and management. We explore the rationale...
Article
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Colloff et al. (2015). Marine and Freshwater Research examined time-series data for flow-dependent vegetation, invertebrates, fish, frogs, reptiles and waterbirds in the Murray-Darling Basin, 1905 2013. They concluded that temporal patterns fluctuated, declining during droughts and recovering after floods. They suggested that major changes in land...
Article
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Colloff et al. in Marine and Freshwater Research (http:dx.doi.org/10.1071/MF14067) examined time-series data for flow-dependent vegetation, invertebrates, fish, frogs, reptiles and waterbirds in the Murray–Darling Basin, 1905–2013. They concluded that temporal patterns fluctuated, declining during droughts and recovering after floods. They suggeste...
Article
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Understanding the causal mechanisms that determine recruitment success is critical to the effective conservation of wild fish populations. Although recruitment strength is likely determined during early life when mortality is greatest, few studies have documented age-specific mortality rates for fish during this period. We investigated age-specific...
Article
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We introduce the river wave concept: a simple, holistic model that unifies river ecosystem concepts. The river wave concept proposes that river flow can be conceptualized as a series of waves varying in shape, amplitude, wavelength, and frequency, traveling longitudinally and laterally; the position on the wave determines the source of organic prod...
Conference Paper
Winemiller and Rose’s life history model (opportunistic, periodic and equilibrium strategies) seeks to explain the adaptations of organisms to a changeable environment. In fishes, these adaptations relate to traits, such as age at maturity, and relative investment in size and number of young. A key element missing from the life history model, howev...
Conference Paper
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The fate and survival of small fishes depends greatly on the successful dispersal from spawning sites to nursery habitats. Dispersal patterns in rivers are shaped by the interplay of behavioural reactions and hydraulic forces. The latter can be influenced by river regulation. Alterations in river morphology (e.g. channelization and shoreline embank...
Conference Paper
Larval dispersal of riverine ecosystems is strongly related to water movement. Currently, numerical models are able to generate flow fields and trajectories of passive particles, which are assumed to represent larval transport. A laboratory study was conducted in a racetrack laboratory flume which contained a shoreline along the inner boundary. Thi...
Conference Paper
Past model studies assumed larvae to behave like simple passive particles. However, in a previous laboratory study (part I: Determination of movement patterns in a racetrack flume and model development) this assumption was shown to be insufficient for riverine ecosystems. Hence, a new concept of an individual based larval model (ILAM) was developed...
Article
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Critical (<30 min) and prolonged (>60 min) swimming speeds in laboratory chambers were determined for larvae of six species of Australian freshwater fishes: trout cod Maccullochella macquariensis, Murray cod Maccullochella peelii, golden perch Macquaria ambigua, silver perch Bidyanus bidyanus, carp gudgeon Hypseleotris spp. and Murray River rainbow...
Article
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Dispersal of fluvial freshwater fish larvae occurs commonly in heavily regulated rivers. Studies increasingly indicate that drifting young fish have an active component to their movement and so are capable of coping with the dynamic hydraulic forces typical of rivers. We investigated hydraulic–drift relationships of the young stages of fish over on...
Article
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The dispersal patterns of marked larvae of the nase carp (Chondrostoma nasus L.) were observed alongside dissimilar shoreline configurations in the main channel of the free-flowing Austrian Danube and compared with those of floating particles to investigate the mode of dispersal (active–passive). Individuals of different larval stages and floats at...
Article
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We develop a swimming costs model that accounts for the influence of flow velocity and body weight on the net active metabolic rate of Murray cod (Maccullochella peelii). Laboratory trials indicated that swimming costs increased with flow velocity (exponent = 2.36) and declined allometrically with body weight (exponent = −0.27). The newly derived s...
Chapter
Ecology of Australian Freshwater Fish (edited by Paul Humphries and Keith Walker) This edited volume reviews our past and present understanding of the ecology of Australian freshwater fishes. It compares patterns and processes in Australia with those on other continents, discusses the local relevance of ecological models from the northern hemispher...
Article
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We present and test an extension of the "match/mismatch" hypothesis that attempts to explain the persistence, under conditions of flow alteration, of small, short-lived, native, riverine, fish species. The premise is that flow alteration typically changes environmental conditions, such as temperature and prey abundance, which may affect survival du...
Article
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The spatial and temporal dynamics of physical habitat in rivers is driven by the interaction between channel morphology and discharge. However, little is known about how altered discharge affects the dynamics of habitat patches such as slackwaters. This study investigated the influence of discharge on the availability, stability, quality, and diver...
Book
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This edited volume reviews our past and present understanding of the ecology of Australian freshwater fishes. It compares patterns and processes in Australia with those on other continents, discusses the local relevance of ecological models from the northern hemisphere and considers how best to manage our species and their habitats in the face of c...
Article
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Little information is available on governing factors of larval fish dispersal in natural river systems. Therefore, we aimed to describe dispersal and retention of marked larval nase carp, Chondrostoma nasus, along a shoreline nursery habitat of the River Danube. Based on a three-dimensional hydrodynamic model, we analyzed the influence of the hydra...
Article
1. The response of a species to environmental disturbance is largely mediated by its life history traits that have evolved within a particular habitat template. Altered flow seasonality, as a direct consequence of river regulation, is a major environmental disturbance and has been implicated in the redistribution of a range of riverine organisms. A...
Article
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This study investigated the importance of dispersal and retention processes during early ontogeny for three caridean shrimp species that complete their entire life history in freshwater. Directional traps were used to examine the small-scale movement patterns of shrimp into and out of nursery habitat patches (slackwaters) in a small lowland river i...
Article
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Driftdensity of young fish in the Austrian Danube: taxonomic and stage specific composition. Drift of young fishes was investigated in the main channel of the Austrian Danube with regard to the taxonomic-and stage specific composition. A total of 7 drifting families were recorded with Gobiids being most abundant. Furthermore we found larvae of the...
Article
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Researchers have hypothesised that influxes of pelagic zooplankton to river channels after floods and high flows are necessary for strong recruitment of some native fish species, including Murray cod (Maccullochella peelii peelii) (Mitchell), in the Murray–Darling river system, Australia. This study investigated the composition of the diet and gut...
Article
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Wilhelm Blandowski is best known for the scandal that surrounded his attempts to name a number of new species of freshwater fish after prominent members of the Victorian scientific establishment. Although this 19 th Century anecdote is diverting, it belies, I believe, the significant contribution that the first paid Victorian government zoologist m...
Article
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The decimation of aquatic wildlife through overexploitation is usually perceived as a marine phenomenon, yet it has also been common in freshwater ecosystems. Fish and other aquatic animals were superabundant when Europeans first arrived in North America and Australia, and were intensively exploited soon after. Contemporaneously, the construction o...
Article
1. A 7-year study was conducted in three hydrologically distinct sections within the highly regulated, lowland Campaspe River to investigate the influence of hydrology on temporal and spatial patterns in fish composition, abundance and recruitment. One section had 6 months, one section 2 months and one section no months of increased flow due to sto...
Article
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Summary Indigenous people demonstrably lived along rivers and around lakes and wetlands of Australia's Murray-Darling Basin in pre-European times. Waterways were, and continue to be, of major significance to the society and culture of Aboriginal peoples throughout Australia. Historically, they exploited most of the fauna – from mussels and crayfish...
Article
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Investigations into the feeding of the early stages of fishes can provide insights into processes influencing recruitment. In this study, we examined ontogenetic changes in morphology and feeding behaviour of two native Australian freshwater species, Murray cod, Maccullochella peelii peelii, and golden perch, Macquaria ambigua, and the alien specie...
Article
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The dynamic nature of habitat patches in rivers is driven primarily by flow regime. Altered hydrology, through river regulation, can limit the size and distribution of slackwater patches; important areas for the development of young fish and for shrimp in lowland rivers. Between late October 2002 and late January 2003, we investigated responses of...
Article
To examine temporal variation in diet, two size classes of western carp gudgeon Hypseleotris klunzingeri were collected from macrophyte habitats in Dugays 2 billabong, a floodplain lake on the River Murray, Victoria, Australia, for 1 year. Fish were collected bimonthly during the day and at night between October 1995 and September 1996. Western car...
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I investigated aspects of the early life history of Murray cod in the Broken River, southern Murray-Darling Basin, Australia. I documented patterns in abundance, length, age and the amount of yolk of drifting free embryos and estimated spawning periods for adult Murray cod in two reaches throughout each breeding season between mid-October and mid-D...
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Wilhelm Blandowski, a Prussian émigré, arrived in Australia in 1849 with hopes of exploring and documenting the natural history of this still relatively scientifically nai;ve colony. After several years travelling, surveying and mining gold, he became the first government zoologist at the infant National Museum of Victoria and was a key player in t...
Article
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Floodplain inundation in rivers is thought to enhance fish recruitment by providing a suitable spawning environment and abundant food and habitat for larvae. Although this model has not previously been tested in Australian rivers, it is often extrapolated to fishes of the Murray-Darling Basin. Fortnightly sampling of larvae and juveniles was conduc...
Article
SUMMARY 1. This paper introduces, and summarises the key messages of, a series of papers that emanated from a symposium on the Role of Drought in the Ecology of Aquatic Systems, held in Australia in 2001. 2. Defining drought hydrologically is problematic because the return times, intensity, duration and long-term trends in low-flow periods are spec...
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In floodplain ponds with low piscivore abundance, both endemic Midgley's gudgeons, Hypseleotris sp. 5, and exotic mosquitofish, Gambusia holbrooki, showed significant ontogenetic variation in the use of food and space. Small gudgeons were generally associated with surface and benthic habitats, then restricted their distribution to benthic habitats...
Article
1. Patterns in abundance and distribution of larval fish in a heavily regulated and a mildly regulated Australian lowland river were compared over four breeding seasons to gain some insight into how river regulation affects fish populations.2. Larvae from a total of 13 species from nine families were recorded from the two rivers. The mildly regulat...
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There is growing awareness that patterns of habitat use by animals cannot be isolated from issues of scale. Recently, techniques have been devised which allow empirical testing of hypotheses related to the effects of spatial scale on habitat use. We used spatially explicit statistical procedures to examine the roles of scale and habitat arrangement...
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ABSTRACT Alterations to the natural hydrologic,regime,in regulated rivers can disrupt cues that initiate the maturation,and spawning of riverine fish, or they can change the conditions which are suitable for the recruitment of larvae into juvenile populations. Observations,of fish larvae have,the potential to provide,insights into the effects of fl...
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Knowledge of the biology of native fishes of the Murray-Darling Basin is based largely on studies conducted under hatchery conditions and on a limited number of recreationally important species. From observations that increases in water level in aquaculture ponds initiate spawning in some species, and from limited studies of wild fishes and studies...
Article
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The macroinvertebrate communities of large lowlandrivers are little studied, partly because of the lackof suitable collection methods. In this study, fourmacroinvertebrate collecting methods: two artificialsubstrates, snags and onion-bag baskets; air-liftsampling of soft sediments; and sweep net sampling ofedges (including macrophyte stands where t...
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The macroinvertebrate assemblages associated with three species of aquatic macrophyte were investigated in a pool in the Macquarie River, Tasmania. Whereas the greatest abundance of macroinvertebrates was found associated in all summer months (ie at all water levels) with the structurally complex and shallowest macrophyte species, Myriophyllum simu...
Article
Littoral habitats in large rivers are influenced to varying degrees by changes in discharge. Irrigation abstractions can increase the amount of habitat that would naturally be dewatered during low flow periods and therefore it is important to have some knowledge of the potential impact this may have on riverine macroinvertebrates. The macroinverteb...
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The reproductive biology, age, growth, food and habitat of Nannoperca australis are described from samples collected from fringing macrophyte beds of the Macquarie River, Tasmania. Comparisons are made with the same species at Narrandera in New South Wales and other nannopercids, mainly in south-western Australia. Nannoperca australis spawned at th...
Article
The growth, age composition, reproductive biology and diet of Galaxiella nigrostriata in seasonal water bodies in south-western Australia are described and compared with G. munda and G. pusilla. Like the other two Galaxiella species, G. nigrostriata has a 1 year life cycle. The mean length attained by female G. nigrostriata at sexual maturity is ap...
Article
The mouth morphology of three species of atherinids, which feed at different levels in the water column (benthos, plankton and water surface) were compared. These three species, which all grow to less than 100 mm in length, inhabit the shallows (<2m) of Wilson Inlet, a temperate south-western Australian estuary. The species could be distinguished p...
Article
The distributions and diets of the six most abundant species of teleost in the shallows of a large south-western Australian estuary were examined from samples collected between March 1988 and February 1989. Fish were collected monthly by seine net from over bare sand and from within patchy and dense areas of the aquatic macrophyte Ruppia megacarpa....