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opencc-by-4.0Dec 2019View details →

Perch positioning affects laying hen locomotion and forces experienced at the keel - FULL DATA SET

Full data set for publication in Animals Perch positioning affects laying hen locomotion and forces experienced at the keel Christina Rufener, Ana K. Rentsch, Ariane Stratmann, Michael J. Toscano

opencc-zeroDec 2015View details →

Data from: An environmental DNA-based method for monitoring spawning activity: a case study, using the endangered Macquarie perch (Macquaria australasica)

Determining the timing and location of reproductive events is critical for efficient management of species. However, methods currently used for aquatic species are costly, time intensive, biased and often require destructive or injurious sampling. Hence, developing a non-invasive sampling method to accurately determine the timing and location of reproduction for aquatic species would be extremely valuable. We conducted an experimental and field study to determine the influence of spawning, and the mass release of spermatozoa in particular, on environmental DNA (eDNA) concentrations. Using a quantitative PCR approach we monitored changes in nuclear and mitochondrial eDNA concentrations over time. The data from the experimental study and the field survey supported our hypothesis that spawning events are characterized by higher concentrations of nuclear relative to mitochondrial eDNA. Outside of the reproductive period, we find that nuclear and mitochondrial DNA fragments are equally abundant in environmental water samples. We have shown that changes in the relative abundance of nuclear and mitochondrial eDNA can be used to monitor spawning activity of the endangered Macquarie perch. Our method is likely to be transferrable to other aquatic species and can be particularly useful to increase our understanding of the spawning biology of cryptic, rare or threatened species as well as design and evaluate environmental management actions and determine species establishment.

Data from: Ecological disturbance influences adaptive divergence despite high gene flow in golden perch (Macquaria ambigua): implications for management and resilience to climate change

Populations that are adaptively divergent but maintain high gene flow may have greater resilience to environmental change as gene flow allows the spread of alleles that have already been tested elsewhere. In addition, populations naturally subjected to ecological disturbance may already hold resilience to future environmental change. Confirming this necessitates ecological genomic studies of high dispersal, generalist species. Here we perform one such study on golden perch (Macquaria ambigua) in the Murray-Darling Basin (MDB), Australia using a genome-wide SNP dataset. The MDB spans across arid to wet and temperate to sub-tropical environments, with low to high ecological disturbance in the form of low to high hydrological variability. We found high gene flow across the basin and three populations with low neutral differentiation. Genotype-environment association analyses detected adaptive divergence predominantly linked to an arid region with highly variable riverine flow, and candidate loci included functions related to fat storage, stress and molecular or tissue repair. The high connectivity of golden perch in the MDB will likely allow locally adaptive traits in its most arid and hydrologically variable environment to spread and be selected in localities that are predicted to become arid and hydrologically variable in future climates. High connectivity in golden perch is likely due to their generalist life history and efforts of fisheries management. Our study adds to growing evidence of adaptation in the face of gene flow, and highlights the importance of considering ecological disturbance and adaptive divergence in biodiversity management.

opencc-zeroDec 2017View details →

Data from: Is barotrauma an important factor in the discard mortality of yellow perch?

In physoclistous fishes, barotrauma caused by rapid decompression during capture may be an important source of fishing mortality that is unquantified for some fisheries. We developed a predictive logistic model for barotrauma incidence in Yellow Perch Perca flavescens and applied this model to Ohio's recreational and commercial fisheries in Lake Erie where discard mortality is implicitly considered to be negligible in current stock assessment. As expected, most of the variation in incidence was explained by capture depth with comparatively small effects of season, sex, and size categories. Measurements of whole body and gonad density provided limited explanation for the categorical effects. Both fisheries spanned a range of depths (7.6 to 16.8 m) that corresponded to a broad range of barotrauma incidence (13 to 74%). Using a recent example, we estimated that additional fishing mortality due to barotrauma in discards was approximately six-fold higher in the commercial than recreational fishery. Overall, this additional mortality was <1% of lake wide population size estimates. Thus, the assumption that all discarded Yellow Perch survive is unlikely to result in a detectable bias in population estimates. One caveat is that we still do not understand how strong year-classes might influence discard mortality via increased discard rate and barotrauma incidence for small fish.

Data from: Elevated temperature and acclimation time affect metabolic performance in the heavily exploited Nile perch of Lake Victoria

Increasing water temperatures due to anthropogenic climate change are predicted to negatively impact the aerobic metabolic performance of aquatic ectotherms. Specifically, it has been hypothesized that thermal increases result in reductions in aerobic scope (AS), which lead to decreases in energy available for essential fitness and performance functions. Consequences of warming are anticipated to be especially severe for warm-adapted tropical species as they are thought to have narrow thermal windows and limited plasticity for coping with elevated temperatures. In this study we test how predicted warming may affect the aerobic performance of Nile perch (Lates niloticus), a commercially-harvested fish species in the Lake Victoria basin of East Africa. We measured critical thermal maxima (CTmax) and key metabolic variables such as AS and excess post-exercise oxygen consumption (EPOC) across a range of temperatures, and compared responses between acute (3-day) exposures and 3-week acclimations. CTmax increased with acclimation temperature, however 3-week acclimated fish had higher overall CTmax than acutely-exposed individuals. Nile perch also showed the capacity to increase or maintain high AS even at temperatures well beyond their current range, however acclimated Nile perch had lower AS compared to acutely-exposed fish. These changes were accompanied by lower EPOC, suggesting that drops in AS may reflect improved energy utilization after acclimation, a finding that is supported by improvements in growth at high temperatures over the acclimation period. Overall, the results challenge predictions that tropical species have limited thermal plasticity, and that high temperatures will be detrimental due to limitations in AS.

opencc-zeroDec 2014View details →

Data from: Benefits of turbid river plume habitat for Lake Erie yellow perch (Perca flavescens) recruitment determined by juvenile to larval genotype assignment

Nutrient-rich, turbid river plumes that are common to large lakes and coastal marine ecosystems have been hypothesized to benefit survival of fish during early life stages by increasing food availability and (or) reducing vulnerability to visual predators. However, evidence that river plumes truly benefit the recruitment process remains meager for both freshwater and marine fishes. Here, we use genotype assignment between juvenile and larval yellow perch (Perca flavescens) from western Lake Erie to estimate and compare recruitment to the age-0 juvenile stage for larvae residing inside the highly turbid, south-shore Maumee River plume versus those occupying the less turbid, more northerly Detroit River plume. Bayesian genotype assignment of a mixed assemblage of juvenile (age-0) yellow perch to putative larval source populations established that recruitment of larvae was higher from the turbid Maumee River plume than for the less turbid Detroit River plume during 2006 and 2007, but not in 2008. Our findings add to the growing evidence that turbid river plumes can indeed enhance survival of fish larvae to recruited life stages, and also demonstrate how novel population genetic analyses of early life stages can contribute to determining critical early life stage processes in the fish recruitment process.

Data from: The interaction between predation risk and food ration on behavior and morphology of Eurasian perch

Both the risk of predation and food level have been shown to affect phenotypic development of organisms. However, these two factors also influence animal behavior that in turn may influence phenotypic development. Hence, it might be difficult to disentangle the behavioral effect from the predator or resource level effects. This is because the presence of predators and high resource levels usually results in a lower activity, which in turn affects energy expenditure that is used for development and growth. It is therefore necessary to study how behavior interacts with changes in body shape with regard to resource density and predators. Here, we use the classic predator induced morphological defense in fish to study the interaction between predator cues, resource availability and behavioral activity with the aim to determine their relative contribution to changes in body shape. We show that all three variables; the presence of a predator, food level and activity, both additively and interactively, affected the body shape of perch. In general, the presence of predators, lower swimming activity and higher food levels induced a deep body shape, with predation and behavior having similar effect and food treatment the smallest effect. The shape changes seemed to be mediated by changes in growth rate since body condition showed a similar effect as shape with regard to food level and predator treatments. Our results suggests that shape changes in animals to one environmental factor, for example predation risk, can be context dependent, and depend on food levels or behavioral responses. Theoretical and empirical studies should further explore how this context dependence affect fitness components such as resource gain and mortality and their implications for population dynamics.

Data from: Genome-wide SNPs identify limits to connectivity in the extreme freshwater disperser, spangled perch Leiopotherapon unicolor (Terapontidae)

The utility of restriction-site associated DNA sequencing (RADseq) to resolve fine-scale population structure was tested on an abundant and vagile fish species in a tropical river. Australia's most widespread freshwater fish, the "extreme disperser" Leiopotherapon unicolor was sampled from six locations in an unregulated system, the Daly River in Australia's Northern Territory. Despite an expectation of high connectivity based on life history knowledge of this species derived from arid zone habitats, L. unicolor was not a panmictic population in the tropical lower Daly. Using ~14,000 polymorphic RADseq loci, we found a pattern of upstream versus downstream population subdivision and evidence for differentiation among tributary populations. The magnitude of population structure was low with narrow confidence intervals (global FST = 0.014; 95% CI = 0.012, 0.016). Confidence intervals around pairwise FST estimates were all non-zero and consistent with the results of clustering analyses. This population structure was not explained by spatially heterogeneous selection acting on a subset of loci, or by sampling groups of closely related individuals (average within-site relatedness ≈ 0). One implication of the low but significant structure observed in the tropics is the possibility that L. unicolor may exhibit contrasting patterns of migratory biology in tropical versus arid zone habitats. We conclude that the RADseq revolution holds promise for delineating subtle patterns of population subdivision in species characterized by high within-population variation and low among-population differentiation.

opencc-zeroDec 2012View details →

Data from: Is the pirate really a ghost? Evidence for generalized chemical camouflage in an aquatic predator, Pirate Perch (Aphredoderus sayanus)

Camouflage occupies a central role in arsenals of both predators and prey and invokes visions of organisms possessing specific characteristics or altering their shape, color, or behavior to blend into the visual background or confound identification. However, many organisms use modalities other than vision. Chemical communication is particularly important in aquatic systems, and chemicals cues are used by a broad array of colonizing organisms to recognize and avoid risky habitats. Here we describe a habitat selection experiment with aquatic beetles and summarize results of 11 experiments involving colonizing beetles and ovipositing tree frogs that provide evidence that pirate perch Aphredoderus sayanus are chemically camouflaged with respect to a diverse array of prey organisms. We believe this to be the first example of a predator possessing a generalized chemical camouflage effective against a broad array of prey organisms, and we suggest that it may constitute a novel weapon in the predator-prey arms race.

opencc-zeroDec 2011View details →

Data from: The role of continental shelf width in determining freshwater phylogeographic patterns in southeastern Australian pygmy perches (Teleostei: Percichthyidae)

Biogeographic patterns displayed by obligate freshwater organisms are intimately related to the nature and extent of connectivity between suitable habitats. Two of the more significant barriers to freshwater connections are seawater and major drainage divides. South-eastern Australia provides a contrast between these barriers as it has discrete areas that are likely influenced to a greater or lesser extent by each barrier type. We use continental shelf width as a proxy for the potential degree of river coalescence during low sea levels. Our specific hypothesis is that the degree of phylogeographic divergence between coastal river basins should correspond to the continental shelf width of each region. This predicts that genetic divergences between river basins should be lowest in regions with a wider continental shelf and that regions with similar continental shelf width should have similar genetic divergences. Pygmy perches (Nannoperca australis and Nannoperca 'flindersi') in south-eastern Australia provide an ideal opportunity to test these biogeographic hypotheses. Phylogeographic patterns were examined based on range-wide sampling of 82 populations for cytochrome b and 23 polymorphic allozyme loci. Our results recovered only limited support for our continental shelf width hypothesis, although patterns within Bass clade were largely congruent with reconstructed low sea-level drainage patterns. In addition, we identified several instances of drainage divide crossings, typically associated with low elevational differences. Our results demonstrate high levels of genetic heterogeneity with important conservation implications, especially for declining populations in the Murray–Darling Basin and a highly restricted disjunct population in Ansons River, Tasmania.

FIGURE 4 in A new species of glass-perch from Belitung Island, Indonesia (Teleostei: Ambassidae: Gymnochanda)

FIGURE 4. Line drawing of head of Gymnochanda flamea. ZRC 22861, 18.8 mm SL male syntype, showing head serration. Scale bar = 1 mm.

FIGURE 1. Gymnochanda verae. a in A new species of glass-perch from Belitung Island, Indonesia (Teleostei: Ambassidae: Gymnochanda)

FIGURE 1. Gymnochanda verae. a. male ca 23 mm SL, living specimen, not preserved; b. female ca 19 mm SL, living specimen, not preserved.

FIGURE 3 in A new species of glass-perch from Belitung Island, Indonesia (Teleostei: Ambassidae: Gymnochanda)

FIGURE 3. Line drawing of head of Gymnochanda verae. MZB 17200, 21.4 mm SL male holotype, showing head serration. Scale bar = 1 mm.

FIGURE 2. Gymnochanda verae. a. MZB 17200, 21.4 in A new species of glass-perch from Belitung Island, Indonesia (Teleostei: Ambassidae: Gymnochanda)

FIGURE 2. Gymnochanda verae. a. MZB 17200, 21.4 mm SL male, holotype; b. MZB 17201, 19.2 mm SL female, paratype.

opennotspecifiedDec 2013View details →

FIGURE 4 in Nannoperca pygmaea, a new species of pygmy perch (Teleostei: Percichthyidae) from Western Australia

FIGURE 4. NJ tree based on pairwise Nei Ds among sties for Nannoperca vittata in seven catchments (Angove River, Goodga River, King River, Mitchell/Hay River, Kalgan River, Quickup River and Marbelup Brook) and Nannoperca pygmaea in the Mitchell/Hay River. See Fig. 1 for site localities.

opennotspecifiedDec 2013View details →

FIGURE 3 in Nannoperca pygmaea, a new species of pygmy perch (Teleostei: Percichthyidae) from Western Australia

FIGURE 3. Principal Co-ordinates Analysis (PCA) of Nannoperca vittata from six river systems (Mitchell (Hay) River, Marbelup Brook, King River, Kalgan River, Angove River, Goodga River) and Nannoperca pygmaea genotyped in the allozyme study. The relative PCA scores have been plotted for the first (X-axis) and second (Y-axis) dimensions, which individually explained 65% and 9%, respectively, of the total multivariate variation. See Fig. 1 for site localities.

opennotspecifiedDec 2013View details →

FIGURE 2 in Nannoperca pygmaea, a new species of pygmy perch (Teleostei: Percichthyidae) from Western Australia

FIGURE 2. Percichthyidae of the South West Coastal Drainage Division, Western Australia. A. Nannoperca pygmaea sp. nov. (WAM P.33380–001, 31.8 mm SL). B. Nannoperca vittata. C. Nannatherina balstoni. D. Bostockia porosa. Bottom, holotype N. pygmaea sp. nov. Photographs S. Beatty and D. Morgan.

opencc-zeroMar 2024View details →

Supplementary material 2 from: Grabowska J, Płóciennik M, Grabowski M (2024) Detailed analysis of prey taxonomic composition indicates feeding habitat partitioning amongst co-occurring invasive gobies and native European perch. NeoBiota 92: 1-23. https://doi.org/10.3897/neobiota.92.116033

Relative abundance of prey categories (%N) (number of given prey category in relation to total number of prey) identified in fish guts at sites Z, R, B in the Western Bug River in August 2007

opencc-zeroMar 2024View details →

Supplementary material 1 from: Grabowska J, Płóciennik M, Grabowski M (2024) Detailed analysis of prey taxonomic composition indicates feeding habitat partitioning amongst co-occurring invasive gobies and native European perch. NeoBiota 92: 1-23. https://doi.org/10.3897/neobiota.92.116033

Relative abundance of species (%N) in fish assemblages found at sites Z, R, B in the Western Bug River in August 2007 (Penczak et al. 2010)