Predation and epibiosis on egg capsules of the Shorttail fanskate, Sympterygia brevicaudata: Depredación y epibiosis sobre cápsulas de la Raya de cola corta, Sympterygia brevicaudata

After deposition, chondrichthyan egg capsules are frequently exposed to numerous threats that affect their survival. However, the ecological factors affecting the development and survival of embryos inside egg capsules remain unclear. The aims of this study was to quantify and describe two ecological factors that affect of the Shorttail fanskate Sympterygia brevicaudata egg capsules: predation and epibiosis. The egg capsules were collected (241) stranded from Coquimbo Bay's intertidal zone in northern Chile (29°57’S; 71°18’W and 71°19’W), and examined predation marks and epibiosis of these egg capsules at different stages of development. About 32.8% of the egg capsules presented evidence of predation marks, of which 48.1% had not yet hatched. Based on our findings, the shape and size of predation marks were different from those reported in the literature. Additionally, 78% of the egg capsules presented epibiosis, of which 21% had not yet hatched. Non-hatched egg capsules with more advanced stages of development (i.e., possessing open respiratory fissures) showed a higher probability to be predated and present epibiosis than those with earlier development (closed respiratory fissures). Ecological interactions, such as predation and the settlement of epibionts, may influence demographic aspects such as hatching success and survival rate, regulating the population sizes of S. brevicaudata during the embryonic phase

Ocean acidification and increased temperature have both positive and negative effects on early ontogenetic traits of a rocky shore keystone predator species

The combined effect of ocean acidification and warming is expected to have significant effects on several traits of marine organisms. The gastropod Concholepas concholepas is a rocky shore keystone predator characteristic of the south-eastern Pacific coast of South America and an important natural resource exploited by small-scale artisanal fishermen along the coast of Chile and Peru. In this study, we used small juveniles of C. concholepas collected from the rocky intertidal habitats of southern Chile (39°S) to evaluate under laboratory conditions the potential consequences of projected near-future levels of ocean acidification and warming for important early ontogenetic traits. The individuals were exposed long-term (5.8 months) to contrasting pCO2 (ca. 500 and 1400 µatm) and temperature (15 and 19°C) levels. After this period we compared body growth traits, dislodgement resistance, predator-escape response, self-righting and metabolic rates. With respect to these traits there was no evidence of a synergistic interaction between pCO2 and temperature. Shell growth was negatively affected by high pCO2 levels only at 15°C. High pCO2 levels also had a negative effect on the predator-escape response. Conversely, dislodgement resistance and self-righting were positively affected by high pCO2 levels at both temperatures. High tenacity and fast self-righting would reduce predation risk in nature and might compensate for the negative effects of high pCO2 levels on other important defensive traits such as shell size and escape behaviour. We conclude that climate change might produce in C. concholepas positive and negative effects in physiology and behaviour. In fact, some of the behavioural responses might be a consequence of physiological effects, such as changes in chemosensory capacity (e.g. predator-escape response) or secretion of adhesive mucous (e.g. dislodgement resistance). Moreover, we conclude that positive behavioural responses may assist in the adaptation to negative physiological impacts, and that this may also be the case for other benthic organisms

Ocean acidification and increased temperature have both positive and negative effects on early ontogenetic traits of a rocky shore keystone predator species

The combined effect of ocean acidification and warming is expected to have significant effects on several traits of marine organisms. The gastropod Concholepas concholepas is a rocky shore keystone predator characteristic of the south-eastern Pacific coast of South America and an important natural resource exploited by small-scale artisanal fishermen along the coast of Chile and Peru. In this study, we used small juveniles of C. concholepas collected from the rocky intertidal habitats of southern Chile (39°S) to evaluate under laboratory conditions the potential consequences of projected near-future levels of ocean acidification and warming for important early ontogenetic traits. The individuals were exposed long-term (5.8 months) to contrasting pCO2 (ca. 500 and 1400 ?atm) and temperature (15 and 19°C) levels. After this period we compared body growth traits, dislodgement resistance, predator-escape response, self-righting and metabolic rates. With respect to these traits there was no evidence of a synergistic interaction between pCO2 and temperature. Shell growth was negatively affected by high pCO2 levels only at 15°C. High pCO2 levels also had a negative effect on the predator-escape response. Conversely, dislodgement resistance and self-righting were positively affected by high pCO2 levels at both temperatures. High tenacity and fast self-righting would reduce predation risk in nature and might compensate for the negative effects of high pCO2 levels on other important defensive traits such as shell size and escape behaviour. We conclude that climate change might produce in C. concholepas positive and negative effects in physiology and behaviour. In fact, some of the behavioural responses might be a consequence of physiological effects, such as changes in chemosensory capacity (e.g. predator-escape response) or secretion of adhesive mucous (e.g. dislodgement resistance). Moreover, we conclude that positive behavioural responses may assist in the adaptation to negative physiological impacts, and that this may also be the case for other benthic organisms

The combined effects of climate change stressors and predatory cues on a mussel species

In order to make adequate projections on the consequences of climate change stressors on marine organisms, it is important to know how impacts of these stressors are affected by the presence of other species. Here we assessed the direct effects of ocean warming (OW) and acidification (OA) along with non-consumptive effects (NCEs) of a predatory crab and/or a predatory snail on the habitat-forming mussel Perumytilus purpuratus. Mussels were exposed for 10–14 weeks to contrasting pCO2 (500 and 1400 μatm) and temperature (15 and 20 °C) levels, in the presence/absence of cues from one or two predator species. We compared mussel traits at sub-organismal (nutritional status, metabolic capacity-ATP production-, cell stress condition via HSP70 expression) and organismal (survival, oxygen consumption, growth, byssus biogenesis, clearance rates, aggregation) levels. OA increased the mussels' oxygen consumption; and OA combined with OW increased ATP demand and the use of carbohydrate reserves. Mussels at present-day pCO2 levels had the highest protein content. Under OW the predatory snail cues induced the highest cell stress condition on the mussels. Temperature, predator cues and the interaction between them affected mussel growth. Mussels grew larger at the control temperature (15 °C) when crab and snail cues were present. Mussel wet mass and calcification were affected by predator cues; with highest values recorded in crab cue presence (isolated or combined with snail cues). In the absence of predator cues in the trails, byssus biogenesis was affected by OA, OW and the OA × OW and OA × predator cues interactions. At present-day pCO2 levels, more byssus was recorded with snail than with crab cues. Clearance rates were affected by temperature, pCO2 and the interaction between them. The investigated stressors had no effects on mussel aggregation. We conclude that OA, OW and the NCEs may lead to neutral, positive or negative consequences for mussels

Average (±SE) conditions of the seawater used to maintain small juveniles of <i>Concholepas concholepas</i> during the acclimatization and treatment phases.

<p>The higher <i>p</i>CO₂ is based on rate of change in pH predicted by the most extreme scenario (RCP8.5 scenario) of atmospheric CO₂ for the beginning of the next century. See Meinshausen et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151920#pone.0151920.ref034" target="_blank">34</a>] for further details.</p

<i>Concholepas concholepas</i>.

<p>Two-way ANOVAs investigating the effect of different combinations of temperature (15 and 19°C) and <i>p</i>CO₂ (500 and 1400 μatm) levels on three body traits changes measured in small juveniles after 5.8 months of rearing in the experimental conditions (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0151920#pone.0151920.g002" target="_blank">Fig 2a and 2d</a>). Values in bold are significant at p < 0.05.</p

Schematic representations of the rearing bottles (a) and chamber used to measure dislodgement force (b-c).

<p>A: air stone, Al: plastic airline, Epl: external plastic lid; Icl: Internal conic lid; Pa: pivoting axis or fulcrum; Hpf: horizontal pivoting flap; Vpf: vertical pivotal flap; Wl: water level; Ei: experimental individual. In (c) the dashed contour depicts the position of the pivoting flap after the dislodgement force had been applied and the Ei was dislodged from the substratum. The black arrow depicts the point where the vertical force with the digital push-dynamometer was applied to the Hpf, and the grey arrow depicts the place where the resulting horizontal force of the Vpf was applied against the Ei.</p