Golden Perch Research Articles

Environmental flow enhances native fish spawning and recruitment in the Murray River, Australia

AbstractEnvironmental flows aim to mimic components of a river's natural flow variability, including the magnitude, frequency, timing, duration, rate of change and the predictability of flow events. Aspects of the natural flow regime are thought to be linked to critical components of the life history strategies of many riverine fishes, including spawning and recruitment. In the Murray River, Australia, environmental flows are increasingly being used as a restoration tool; however, there is little information about the response of fish to these managed flow events. This study reports on the results from a 3‐year study on the effects of water management on the spawning and recruitment of four native fish species in the mid‐Murray River system. Two of these years were hydrologically similar, while the third year encompassed an extensive period of floodplain inundation, including the use of the largest environmental flow allocation to date in Australia. Drift nets were used to collect the drifting eggs and larvae of four iconic native species throughout their spawning season each year. Young‐of‐year were collected in the following autumn. Although golden perch and silver perch eggs were collected in all 3 years, both species increased their spawning activity during the major flood period compared to the previous two seasons. Murray cod and trout cod appeared not to increase their spawning activity in the flood year, but their recruitment may be increased when floodplain inundation occurs at times when their larvae and juveniles are present, most likely through the generation of abundant food resources. Whilst further study is required to confirm the role and mechanism of flooding in the spawning and recruitment of these species; this study provides important evidence of a link between the provision of an environmental flood and fish spawning and recruitment, and has significant implications for managing flows in regulated rivers. Copyright © 2008 John Wiley & Sons, Ltd.

Factors influencing recruitment patterns of Golden Perch (Macquaria ambigua oriens) within a hydrologically variable and regulated Australian tropical river system

Abstract – The links between river flows, water temperature, river regulation and recruitment variability of Golden Perch, Macquaria ambigua oriens, were investigated from the Fitzroy Basin, Queensland. The dominant age classes determined by interpreting growth marks observed in otoliths were variable among rivers. Positive correlations between the age frequency and monthly river flow volumes were greatest in summer (December–March) conversely, autumn, winter and spring river flows correlated poorly for most rivers. Water temperature exhibits strong seasonality across the basin with mean monthly temperatures >23 °C generally occurring between October and April. These data indicate the combination of water temperature and increased river flows are important factors for recruitment. The degree of river regulation is also suspected of contributing to increased variability in dominant age classes within rivers. This assessment highlights the importance of timing of river flows in mitigating the negative effects of river regulation on golden perch populations.

Enriched stable isotope marking of juvenile golden perch (Macquaria ambigua) otoliths

Stocking of native fish is a standard practice to aid in the recovery and enhancement of depleted populations. However, evaluating the effectiveness of these stocking programs has been hindered because of difficulty in distinguishing hatchery from wild fish, especially for species that are stocked as small, fragile fingerlings. Stable isotopes offer the potential to chemically mark fish with multiple marks that are distinct from each other and from natural signatures. Golden perch (Macquaria ambigua) fingerlings were reared in water enriched in 137Ba and combinations of 137Ba and 86Sr for various lengths of time. Ba and Sr isotopic ratios in the otoliths were determined using laser ablation inductively coupled plasma-mass spectrometry. Fish exposed to increased levels of 137Ba had lower 138Ba/137Ba ratios in their otoliths relative to the natural ratio of control fish and were significantly different in fish exposed to at least 5 µg·L-1 for 8 days or to 15 µg·L-1 for 4 days. Furthermore, eight unique signatures were produced in fish reared in combinations of 137Ba (0–5 µg·L-1) and 86Sr (0–100 µg·L-1) for 24 days. Our results suggest that immersion in water enriched in specific stable isotopes could be an effective means of marking hatchery-reared fish for stock enhancement.

Flow‐related patterns in abundance and composition of the fish fauna of a degraded Australian lowland river

Summary1. 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 storage releases. The fish fauna of the less regulated, nearby Broken River served as a reference to which that of the Campaspe River was compared for the last 3 years of the study to allow insight into the relative effects of hydrology, barriers to movement and other environmental characteristics. The study included one high‐flow year, a moderate‐flow year and five low‐flow years.2. A total of 16 fish species – 10 native and six alien – were caught in the Campaspe River, although of the native species, only three are considered to have self‐sustaining populations. The remaining species are either itinerants or a result of stocking. Alien species comprised approximately 64% of the total biomass of all fish caught.3. Overall composition of the fish fauna did not differ significantly by year, but did by section of river. Species richness and the abundance of most of the dominant species also differed significantly by river section, but there was little inter‐annual variation in the abundance of any species, except for European perch and for common carp; the latter showing an increase in abundance following a high‐flow event during the spring of 2000 as a result of recruitment.4. Overall faunal composition was not influenced by hydrology. However, multiple regression indicated that species richness, abundance of the dominant species and abundance of young‐of‐year (YOY) of golden perch, European perch and common carp all were influenced significantly by hydrological variables. The nature of the relationships was dependent on river section and hydrological season (‘winter’ or ‘spring/summer’). Of note was the result that the total abundance of fish and that of YOY common carp were significantly positively related to the number of spells above the threshold for movement upstream through the lower two weirs in the Campaspe River. Only one significant relationship between hydrological and fish‐related variables was found for the upper river section, whereas seven and five were found for the lower and middle sections respectively.5. Comparisons with fish collected in the Broken River over 3 years suggest that the fauna of the Broken River is in a more natural state than that of the Campaspe River. Since the two rivers do not differ substantially in water quality, and since both contain significant weirs, which act as barriers to movement of fish, flow regulation is most likely to be the major reason for the poor state of the fauna in the Campaspe River.

Determining diel variation in fish assemblages downstream of three weirs in a regulated lowland river

The diel variation in boat electrofishing catches was investigated on the lower Murray River (south‐eastern Australia), downstream of three low‐level weirs. Fish assemblage composition did not differ among three sites, but differed substantially between day and night. Significantly more small‐bodied species (e.g. Australian smelt Retropinna semoni, flyspecked hardyhead Craterocephalus stercusmuscarum, bony herring Nematalosa erebi and Murray rainbowfish Melanotaenia fluviatilis) and some large‐bodied predators (e.g. golden perch Macquaria ambigua) were caught during daytime samples. Significantly more flatheaded gudgeon Phylipnodon grandiceps, carp gudgeon Hypseleotris spp. and perch Perca fluviatilis were collected at night. The size composition of the fish assemblage also changed over the diel cycle. Significantly smaller goldfish Carassius auratus, flyspecked hardyhead, bony herring and Australian smelt were sampled during the day, while generally smaller individuals of golden perch and the common carp Cyprinus carpio were caught at night. These findings suggest that sampling during both day and night is required to adequately characterize riverine fish assemblages in the context of fish migration studies.

Can a low-gradient vertical-slot fishway provide passage for a lowland river fish community?

Fishways are commonly used to restore native fish movements in regulated rivers. In the Murray-Darling Basin, Australia, 14 fishways are to be built by 2011 to improve passage along 2225 km of the river. The first of these fishways, constructed in 2003, is a vertical-slot design with low water velocities (0.98–1.4 m s–1) and turbulence (average 42 W m–3). This design was selected to provide passage for individuals between 20 and 1000 mm long. To determine passage success, trapping and a remote automated passive integrated transponder (PIT) tag reading system was used from October 2003 to February 2006. In 57 24-h samples at the exit (upstream end) and entrance (downstream end), 13 species and 30 409 fish were collected at a maximum rate of 4415 fish per day. Fish between 31 and 1030 mm successfully ascended the fishway. However, significantly smaller (<31 mm) fish and small-bodied (<50 mm) carp gudgeons (Hypseleotris spp.), a species previously considered non-migratory, were sampled downstream from the entrance of the fishway. The remote PIT tag reading system revealed that 81% of native golden perch (Macquaria ambigua) and 87% of non-native common carp (Cyprinus carpio) successfully ascended the fishway. These data will help maximise the efficiency of future fishways against a series of pre-determined performance criteria.

Estimation of Growth of the Golden PerchMacquaria ambiguabased on a tagging program between 1959 and 1970

A tagging/recapture program was carried out on large freshwater fish species in the Murrumbidgee and Murray Rivers to examine their growth. Internal body tags were found to be more reliable than opercular tags. Adequate recapture data for further analysis was only obtained for Golden Perch Macquaria ambigua. Monthly frequency of recapture appeared to follow angling pressure. The length/ weight relationship curves of recaptured fish at tagging and recapture are similar (y=1.49E-06x3393 and y= 7.32E-06x31374 respectively), supporting the use of the data for growth analysis. Von Bertalanffy growth curves [Lt=L∞(I-e-k(t-to))] were constructed, where Lt =length at time t; and for all fish recovered L∞ (asymptotic length) = 550.6 mm, k (growth parameter) =0.2458 and t0 (hypothetical age in years at zero length) = 0.1333. The parameters determined for Murrumbidgee females indicated a more rapid growth than males. Murray River fish grew more rapidly than Murrumbidgee fish. Values of L∞ and k based on the method o...

Nursery Production of Golden Perch, Macquaria ambigua, at Two Densities in Ponds

ABSTRACT Golden perch, Macquaria ambigua (Richardson), is a freshwater percichthyid native to inland eastern Australia. Growth and feeding of this fish in pond aquaculture conditions was studied in nursery phase at high (95,300/ha) and low (32,800/ha) density over 126 days. Mean growth of golden perch at both densities was similar, but there were significantly more small fish in the high-density treatment. Coefficient of variation was high in both treatments (72–79%). After 126 days, 67% of the fish in both treatments reverted to natural foods. Reversion from pelleted diet to natural foods was very rapid in the low-density treatment (<14 days), but slower in the high-density treatment. Golden perch were found to be selective feeders. The smallest fish selectively ate water fleas, Moina sp., from the zooplankton, and larger fish ate chironomids and caddis flies (Trichoptera). Golden perch, which fed predominantly on pellets, grew 54% faster than those eating natural foods. Three to four months of an intensive nursery period, followed by grading for grow-out, is recommended to separate fast growing pellet feeding fish from slower growing fish that have reverted to eating natural foods.

Effects of temperature on the fast‐start swimming performance of an Australian freshwater fish

Abstract – The fast‐start swimming performance of juveniles of an Australian freshwater (warm‐water) fish, golden perch, was examined in the laboratory at six water temperatures ranging between 10 and 25 °C. Fast‐start swimming performance of fish was considerably reduced at temperatures less than 15.5 °C. Temperatures of less than 15 °C are typical of the thermal regime downstream of large dams in south‐eastern Australia, where conditions are more suited to introduced cold‐water fish species. We conclude that the swimming performance of native warm‐water fish such as golden perch is likely to be negatively affected by cold‐water releases from deep outlets in thermally stratified dams.

Production of External Fluorescent Marks on Golden Perch Fingerlings through Osmotic Induction Marking with Alizarin Red S

AbstractOsmotic induction marking trials with alizarin red S (ARS) were conducted on golden perch Macquaria ambigua to evaluate the use of ARS as a lower‐cost alternative to osmotic induction marking with calcein for producing external fluorescent marks on hatchery‐produced fish. After a 10‐min immersion in a 5% solution of salt, experimental groups of golden perch were rinsed for 5 s in freshwater and immersed for 10 min in either a 0.1% or 0.5% solution of ARS, whereas control groups were either left untreated or immersed in a 0.1% solution of ARS for 10 min without prior immersion in the salt solution. All fish treated in the 0.5% solution of ARS died within 5 min of immersion, but no mortalities were observed in any of the controls or fish treated with the 0.1% solution of ARS. External fluorescent marks were observed on both the osmotic induction‐marked fish and the direct ARS immersion‐marked fish 100 d after treatment, but the osmotic induction‐marked fish possessed more intense marks. Clear marks remained visible on fish marked by osmotic induction 9 months after treatment. This study indicates that highly visible external marks can be produced through osmotic induction with ARS at a substantially lower cost than marks produced through osmotic induction with calcein. Although further refinement and testing are needed, we conclude that the method has considerable potential for use in the mass marking of fish.

Diet and feeding habits of predatory fishes upstream and downstream of a low‐level weir

A study investigating the influence of a low‐level weir on the diets of three migratory percithyid species was undertaken on the Murrumbidgee River, Australia. A combination of fish community sampling and stomach flushing determined that Yanco Weir substantially impacted upon the abundance and feeding habits of golden perch Macquaria ambigua, Murray cod Maccullochella peelii peelii and trout cod Maccullochella macquariensis. The relative abundance of all three species was significantly greater downstream of the weir, where individuals attempting upstream migrations were obstructed. In areas of fish aggregations, some species displayed altered feeding strategies and exploited different prey taxa upstream and downstream of the weir. Diet overlap, and the proportion of individuals with empty stomachs, was also substantially greater from downstream zones. These results suggest that competition among species may be greater in areas of increased predator abundance and some species could be partitioning resources to minimize competitive interactions. Reducing accumulations of predatory species, by providing suitable fish passage facilities, would be an effective means to prevent such trophic interactions occurring at other low‐level weirs.

Murray cod an apex predator in the Murray River, Australia

Abstract – To determine if the Murray cod Maccullochella peelii peelii is an apex predator in the lowland rivers of the Murray‐Darling Basin, its feeding ecology was compared with that of the sympatric top predator, golden perch Macquaria ambiguaambigua based on samples supplied by recreational anglers. Diet and prey size were reconstructed from alimentary tract contents of Murray cod (N = 39) and golden perch (N = 52), and their feeding morphology was assessed and included calculation of length–gape relationships and relative gut index. Both species fed principally on fish and decapods although Murray cod was the more piscivorous (frequency of occurrence 44% versus 6%, total number 50% versus 2%, total weight 90.4% versus 16.0%). Based on reconstructions of prey sizes, fishes up to 1 kg in weight were preyed on by Murray cod, distinguishing it from other top predatory fishes in the Murray‐Darling Basin and supporting its classification as an apex predator.

Ontogeny of feeding in two native and one alien fish species from the Murray-Darling Basin, Australia

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 species, common carp, Cyprinus carpio. Murray cod free embryos are large and well developed at the onset of feeding, whereas the other two species begin exogenous feeding much younger and are smaller and less-developed. Carp commence exogenous feeding 3 days earlier than golden perch, and show more advanced development of the eyes and ingestive apparatus. We conducted feeding experiments, presenting larvae of the three species with a standardised prey mix (comprising equal numbers of small calanoid copepods, large calanoid copepods, small Daphnia, and large Daphnia). Larvae of most tested ages and species showed a preference for mid-sized prey (300–500 µm wide). This was true even when their gapes substantially exceeded the largest prey offered. Daphnia were consumed more than similar-sized copepods. The results of this study suggest that survival through their larval period will be threatened in all three species if catchable prey <500 µm in width are not available throughout such time. They also suggest that interspecific competition for prey may occur, especially when larvae are very young. The precocious development of structures involved in feeding and the extended transition from endogenous to exogenous feeding of early carp larvae are likely to have contributed to the success of this species since its introduction to Australia.

A Large-scale, Hierarchical Approach for Assessing Habitat Associations of Fish Assemblages in Large Dryland Rivers

Multiple-scale assessments of fish-habitat associations are limited despite the fact that riverine fish assemblages are influenced by factors operating over a range of spatial scales. A method for assessing fishhabitat assemblages at multiple scales is proposed and tested in a large Australian dryland river, the Barwon–Darling River. Six discrete mesohabitat types (large wood, smooth bank, irregular bank, matted bank, mid-channel and deep pool) nested within 10 km long river reaches were sampled. Individual reaches were, in turn, nested within four larger geomorphological zones, previously identified along the river. Fish assemblages varied significantly between mesohabitat types and at different spatial scales. Golden perch (Macquaria ambigua), Murray cod (Maccullochella peelii peelii) and common carp (Cyprinus carpio) were strongly associated with large wood, but golden perch and Murray cod exhibited higher habitat specificity than carp. Bony herring (Nematalosa erebi) were more common in shallow edgewater habitats. At the riverscale, regional differences in the fish assemblage occurred at scales closely corresponding to geomorphological zones and these differences were associated with changes in the relative abundance of species rather than the addition or replacement of species. The proposed hierarchical framework improves the efficiency of fish surveys in large rivers by viewing meso-scale fish-habitat associations in the context of larger-scale geomorphological processes.

Validation of Otoliths for Determining Age of Golden Perch, a Long‐Lived Freshwater Fish of Australia

AbstractSectioned sagittal otoliths have been validated for age determinations of golden perch Macquaria ambigua to age 9. However, previous studies have estimated ages up to 26 years. I used two known‐age fish of ages 20 and 22 years to confirm that sectioned otoliths are valid for estimating the true age of old golden perch. The present study has validated the periodicity and stability of annulus formation over a long period of time as well as the accuracy of the age estimates. Accurate age assessments and confirmation of the consistency of annulus formation over time (&gt;20 years) are important for increasing confidence for managers of the remaining golden perch populations.

Mortality of larval Murray cod (Maccullochella peelii peelii) and golden perch (Macquaria ambigua) associated with passage through two types of low-head weirs

Determining factors responsible for increases in the mortality of freshwater fish larvae are important for the conservation of recruitment processes and for the long-term sustainability of freshwater fish populations. To assess the impact of one such process, Murray cod (Maccullochella peelii peelii Mitchell) and golden perch (Macquaria ambigua Richardson) larvae were arranged into treatment and control groups and passed through different configurations (overshot and undershot) of a low-level weir. Passage through an undershot weir resulted in the death of 95 ± 1% golden perch and 52 ± 13% Murray cod. By comparison, mortality was significantly lower in the overshot treatment and both controls. The relatively large number of undershot weirs within the known distribution of these species could impact upon recruitment over a large scale. It is therefore recommended that water management authorities consider the potential threats of operating undershot gated weirs on the survival of larval fish until further research determines appropriate mitigatory measures for these and other species.

The effects of in vitro pesticide exposures on the phagocytic function of four native Australian freshwater fish

There are limited data concerning the lethal and sublethal effects of environmental pollutants on Australian freshwater fish and consequently many of the Australian water quality guidelines are based on data from exotic fish species. This study used a flow cytometric assay to assess the effect of in vitro exposures to commonly used pesticides, on the phagocytic function and cellular composition of head kidney cells from four Australian native fish, i.e. crimson-spotted rainbowfish ( Melanotaenia fluviatilis), silver perch ( Bidyanus bidyanus), golden perch ( Macquaria ambigua) and Murray cod ( Maccullochella peelii). Head kidney immune cells were isolated from the four native fish and incubated (1 × 10 6 cells/mL) under previously optimised conditions to measure the phagocytosis of fluorescent-latex beads. These cell cultures were exposed to three classes of pesticides, i.e. the organotins, tributyltin and dibutyltin, the organochlorine endosulfan and the organophosphate chlorpyrifos. The in vitro organotin exposures were highly immunotoxic to head kidney cells from the Australian fish, although there were some differences in immunotoxic responses between species. At the highest concentration (i.e. 10 mg/L), endosulfan exposure resulted in the modulation of phagocytic responses in all species except for silver perch. Chlorpyrifos displayed little immunotoxicity, although there was a dose-dependent reduction in Murray cod lymphocytes. These studies describe the first investigation of the phagocytic response of Australian freshwater fish immunocytes in the presence of environmental pollutants, and will help to determine appropriate ecotoxicity testing for Australian freshwater environments.

Flow cytometric analysis and optimisation for measuring phagocytosis in three Australian freshwater fish

The phagocytic activity of fish immunocytes has been measured by a wide range of methods, and has been used as a bio-indicator to assess the immunotoxicity of environmental pollutants and the efficiency of immunostimulants used in aquaculture. This study demonstrates the utilisation of a flow cytometric technique for measuring phagocytosis as an alternative to manual evaluations by light microscopy. Optimal conditions for the phagocytosis of latex beads were ascertained, including incubation period, cell:bead ratio and media components, for head kidney cells isolated from three native Australian fish that inhabit the Murray–Darling basin, i.e. silver perch ( Bidyanus bidyanus), golden perch ( Macquaria ambigua) and crimson-spotted rainbowfish ( Melanotaenia fluviatilis). Thus, standardised protocols have now been established for future use in the immunotoxicity testing of xenobiotics in native Australian freshwater fish.

Gill ATPase activities of silver perch, Bidyanus bidyanus (Mitchell), and golden perch, Macquaria ambigua (Richardson): Effects of environmental salt and ammonia

The Australian freshwater fish, silver and golden perch, are increasingly being used for aquaculture. Addition of salt to water is commonly used in commercial aquaculture to reduce stress attributed to high ammonia concentrations. The activities in gill homogenates of ouabain-sensitive Na +/K +-ATPase and NEM-sensitive ATPases (as a measure of H +-ATPases) of silver and golden perch were measured after maintaining the fish in water containing different salt and ammonia concentrations. Six treatments were applied in a 2 × 3 factorial design: two salt treatments, low salt (LS) of 2.5 g l − 1 and high salt (HS) 5 g l − 1 , and three ammonia treatments, no added ammonia (NA), low ammonia (LA), 3 mg total ammonia nitrogen (TAN) l − 1 and high ammonia (HA), 5 mg TAN l − 1 . In both species, activity of Na +/K +-ATPase was lowest in fish kept in the LSNA treatment (7.4 ± 0.4 μmol Pi mg protein − 1 h − 1 for silver perch and 3.1 ± 0.6 for golden perch) and highest in the HSHA treatment (15.2 ± 1.0 μmol Pi mg − 1 protein h − 1 for silver and 8.4 ± 1.2 for golden perch). In both species there was a significant increase ( P < 0.001) in Na +/K +-ATPase activity with increase in salt concentration and with an increase in ammonia concentrations. A significant interaction ( P < 0.036) between salt and ammonia on Na +/K +-ATPase activity was observed in silver but not in golden perch. In contrast, the lowest activity for NEM-sensitive ATPase was observed in the HSNA treatment (1.0 ± 0.2 μmol Pi mg − 1 protein h − 1 for silver and 1.5 ± 0.4 for golden perch) and highest in LSHA treatment (2.9 ± 0.4 μmol Pi mg − 1 protein h − 1 for silver and 3.6 ± 1.2 for golden perch). In both species there was a significant decrease in NEM-sensitive ATPase activity with increase in salt concentration and an increase in activity with increase in ammonia ( P < 0.003). In silver perch, a significant interaction between the treatments was observed ( P < 0.02). The results suggest that in these species of freshwater fish the Na +/K +-ATPase has a role in salt and ammonia homeostasis and that the NEM-sensitive ATPases are more active in fish kept in water with a lower salt content. It is possible that the increase in ammonia resistance when salt is added to the environmental water in commercial aquaculture systems may be due to the effects of salt on gill Na +/K +-ATPase activity rather than the NEM-sensitive ATPases.

Movements of Macquaria ambigua, in the Murray River, south‐eastern Australia

A 2 year (2000–2001) radio‐tagging study was undertaken to investigate the movements of 51 golden perch Macquaria ambigua in the Murray River at Nyah in north‐western Victoria, Australia. During the winter of both years, golden perch did not undertake movements &gt;5 km and displayed strong home range fidelity. In the first year of the study there was an increase in the distance of golden perch movement during late spring which coincided with increasing water temperature and river discharge. Nineteen golden perch were tracked during this period, of which 10 travelled downstream between 11 and 290 km. Seven of these fish moved to an area below the junction of the Murray and Wakool Rivers. Five golden perch travelled upstream between 13 and 35 km, four of which travelled to an area around the junction of the Murray River and Speewa Creek. The remaining four golden perch undertook localized movements of &lt;5 km. Many of the long distance movements undertaken in spring 2000 were rapid and 53% of these golden perch returned to within 3 km of their release locations, indicating homing behaviour. Given that the rapid movements of golden perch in spring coincided with the known spawning season of this species, these long distance movements may be associated with reproductive strategy.