Two-way ANOVA for percent motility (A) and sperm speed (B) of <i>Heliocidaris erythrogramma</i> across different pH treatments (fixed) and males (random).

<p>Significant effects (<i>P</i>≤0.05) are shown in bold.</p

Seawater parameters for the three different pH treatments.

<p>pH<b>_NBS</b>, temperature (T), salinity (Sal) and total alkalinity (A_T) were measured directly and used to compute partial pressure levels of carbon dioxide (<i>p</i>CO₂) and seawater saturation states for calcite and aragonite (Ω_Ca and Ω_Ar respectively) using CO2SYS. Means ± S.E.</p

Scatterplots for observed (FSR_obs) versus modelled (FSR_mod) fertilization success for pH 7.8 (A) and 7.6 (B).

<p>Regression analyses revealed a significant relationship between observed (independent) and modelled fertilization (dependent) for pH 7.8 (<i>P</i> = 0.012, r² = 0.336), but not for pH 7.6 (<i>P</i> = 0.413, r² = 0.042).</p

Modelled (FSR_mod) and observed (FSR_obs) fertilization success for each urchin pair under acidified conditions (pH 7.6 and 7.8), and parameters from Control observations (pH 8.1) used in modelling FSR_mod at lowered pH levels.

<p>FSR_{50 Control} = 50% of maximum fertilization success in Controls; <i>F</i>_{50 Control} = sperm concentration that generates 50% of maximum fertilization success in Controls. Sperm data from each male in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053118#pone-0053118-t002" target="_blank">Table 2</a> were used in modelling FSR_mod. No females were spawned for male A.</p

Ocean acidification effects on sperm speed and percent sperm motility for each male <i>Heliocidaris erythogramma</i>.

<p>Significant differences in parameters between sites (<i>P</i>≤0.05) are shown in bold.</p

Impacts of ocean acidification on sperm motility and sperm swimming speed in <i>Heliocidaris erythrogramma.</i>

<p>Proportion of mean (±S.E.) motile sperm (A) and sperm speed (B) at different levels of ocean acidification (pH mediated by CO₂ addition). Lower case letters indicate significantly different groups at <i>p</i> = 0.05 (Tukey’s test). (C) Mean logarithmic response ratios (±95% CI) of effects of ocean acidification on percent motility and sperm speed (n = 19).</p

Two-way ANOVA for observed (FSR_obs; A) and modelled fertilization success (FSR_mod; B) of <i>Heliocidaris erythrogramma</i> across different pH treatments (fixed) and males (random).

<p>Significant effects (P≤0.05) are shown in bold.</p

Effects of ocean acidification on fertilization success (FSR) in <i>H. erythrogramma</i>.

<p>(A) Mean (±S.E.) observed (FSR_obs) and modelled fertilization success (FSR_mod) for pHs 7.6 and 7.8, and mean (±S.E.) FSR₅₀ (50% of maximum FSR) for pH 8.1. (B) Bootstrapped mean logarithmic response ratios (±95% CI) of effects of ocean acidification on FSR_obs and FSR_mod. FSR_mod shows change in fertilization success expected due to ocean acidification’s influence on sperm swimming behaviour (Fig. 2C). (n = 18 replicate trials). See text for details.</p

Diets and Resource Partitioning among Three Sympatric Gurnards in Northeastern Tasmanian Waters, Australia

<p>Dietary niches can support the coexistence of closely related sympatric species in marine systems, which can lead to the presence of greater abundances of those species that can potentially support their fisheries or greater abundances for other fish species that prey upon those species. Dietary relationships for three species of gurnard (Family Triglidae) that occur together in the benthic coastal environment of northeastern Tasmania, Australia (Red Gurnard <i>Chelidonichthys kumu</i>, Grooved Gurnard <i>Lepidotrigla modesta</i>, and Roundsnout Gurnard <i>Lepidotrigla mulhalli</i>), were examined for the presence of such dietary niches. The species are either fishery-important (Red Gurnard) or provide prey (Grooved Gurnard and Roundsnout Gurnard) for fishery-important species (e.g., Platycephalidae and Zeidae). Based on stomach content analyses, all three gurnards were shown to be bottom-feeding carnivores that consumed mainly benthic crustaceans, particularly decapods and amphipods, with teleosts also being important in the diets of only the larger Red Gurnard. Nonmetric multidimensional scaling ordination and multivariate analyses based on volumetric contributions of different prey taxa to the stomach contents revealed significant differences in dietary composition among all three species, implying a partitioning of food resources. Size-related and temporal changes in dietary composition were each significant among the three gurnards, but there were no interactions between body size and time. Principal components analysis of head and mouth morphology demonstrated that mouth protrusiveness was the dominant morphological difference among species, which may in part account for the niche partitioning observed from the stomach content analysis. Given the important role of gurnards in benthic food webs, these relationships will improve the specification of ecosystem-based fisheries models and their ability to predict the effects of environmental and anthropogenic perturbations.</p> <p>Received June 29, 2016; accepted April 9, 2017</p

Appendix A. Centrostephanus rodgersii sampling site data and genetic summary statistics.

Centrostephanus rodgersii sampling site data and genetic summary statistics