Mirjam AmcoffResearch Analyst
A selection from Stockholm University publication database
Long-term exposure to elevated carbon dioxide does not alter activity levels of a coral reef fish in response to predator chemical cues
2017. Josefin Sundin (et al.). Behavioral Ecology and Sociobiology 71 (8)Article
Levels of dissolved carbon dioxide (CO2) projected to occur in the world's oceans in the near future have been reported to increase swimming activity and impair predator recognition in coral reef fishes. These behavioral alterations would be expected to have dramatic effects on survival and community dynamics in marine ecosystems in the future. To investigate the universality and replicability of these observations, we used juvenile spiny chromis damselfish (Acanthochromis polyacanthus) to examine the effects of long-term CO 2 exposure on routine activity and the behavioral response to the chemical cues of a predator (Cephalopholis urodeta). Commencing at similar to 3-20 days post-hatch, juvenile damselfish were exposed to presentday CO2 levels (similar to 420 mu atm) or to levels forecasted for the year 2100 (similar to 1000 mu atm) for 3 months of their development. Thereafter, we assessed routine activity before and after injections of seawater (sham injection, control) or seawater-containing predator chemical cues. There was no effect of CO2 treatment on routine activity levels before or after the injections. All fish decreased their swimming activity following the predator cue injection but not following the sham injection, regardless of CO2 treatment. Our results corroborate findings from a growing number of studies reporting limited or no behavioral responses of fishes to elevated CO2. Significance statement Alarmingly, it has been reported that levels of dissolved carbon dioxide (CO2) forecasted for the year 2100 cause coral reef fishes to be attracted to the chemical cues of predators. However, most studies have exposed the fish to CO2 for very short periods before behavioral testing. Using long-term acclimation to elevated CO2 and automated tracking software, we found that fish exposed to elevated CO2 showed the same behavioral patterns as control fish exposed to present-day CO2 levels. Specifically, activity levels were the same between groups, and fish acclimated to elevated CO2 decreased their swimming activity to the same degree as control fish when presented with cues from a predator. These findings indicate that behavioral impacts of elevated CO2 levels are not universal in coral reef fishes.
Multiple male sexual signals and female responsiveness in the swordtail characin, Corynopoma riisei
2015. Mirjam Amcoff, Niclas Kolm. Environmental Biology of Fishes 98 (7), 1731-1740Article
In the courtship process, multiple signals are often used between the signaller and the receiver. Here we describe female response to multiple male visual morphological and behavioural signals in the swordtail characin, Corynopoma riisei. The swordtail characin is a species in which males display several morphological ornaments as well as a rich courtship repertoire. Our results show that high courtship intensity was associated with an increased female response towards the male ornament, increased number of mating attempts and a reduction in female aggression. The morphological aspects investigated here did not seem to correlate with female response. This may indicate that, when both behaviour and morphology are considered simultaneously, courtship behaviour may have priority over morphological cues in this species.
Does female feeding motivation affect the response to a food-mimicking male ornament in the swordtail characin Corynopoma riisei?
2013. Mirjam Amcoff, Niclas Kolm. Journal of Fish Biology 83 (2), 343-354Article
Female response to various aspects of male trait morphology and the effect of female feeding motivation were investigated in the swordtail characin Corynopoma riisei, a species where males are equipped with a flag-like food-mimicking ornament that grows from the operculum. Unfed females responded more strongly to the male ornament and showed a stronger preference for larger ornaments than did fed females. Females were shown not to discriminate between artificial male ornaments of either undamaged or damaged shape.