Corrigendum: The significance of cephalopod beaks as a research tool: An update.

[This corrects the article DOI: 10.3389/fphys.2022.1038064.].

The significance of cephalopod beaks as a research tool: An update.

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960's, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed.

First indication of deleterious impacts in white-seabream larvae (Diplodus sargus) survival and behaviour following acute venlafaxine exposure.

Wastewater effluents are teeming with organisms, nutrients and chemical substances which water treatment processes fail to remove. Among these substances, pharmaceuticals such as antidepressants are a frequent occurrence, and have been reported to lead to severe effects in the physiology and behaviour of non-target marine species across taxa. Venlafaxine (VFX) is one of the most consistently prescribed substances for the treatment of human depressive disorders, acting as a serotonin and norepinephrine reuptake inhibitor. In the present study, the potential effects of this antidepressant on the survival and key behaviours (i.e. movement, aggression and foraging) of white seabream (Diplodus sargus) larvae were addressed. Larvae were submitted to an acute exposure of two different VFX treatments (low concentration, 10 µg L-1; and high concentration, 100 µg L-1) for a total of 48 h. Sampling took place after 24 and 48 h of exposure. Overall, results showed a significant effect of a two-day exposure to VFX in larvae of D. sargus. Survival was significantly reduced by exposure to a high concentration, but behavioural effects of antidepressant exposure were subtle: i.e. increased attack frequency and temporary modulation of capture success. Further research efforts should be directed towards evaluating the potential chronic effects of antidepressants in marine species, if we are to anticipate possible pressures on natural populations, and effectively advice policymakers towards the investment in new and more efficient methods of wastewater treatments.

Differential behavioural responses to venlafaxine exposure route, warming and acidification in juvenile fish (Argyrosomus regius).

Antidepressants, such as venlafaxine (VFX), which are considered emerging environmental pollutants, are increasingly more present in the marine environment, and recent evidence suggest that they might have adverse effects on fish behaviour. Furthermore, altered environmental conditions associated to climate change (e.g. warming and acidification) can also have a determinant role on fish behaviour, fitness and survival. Yet, the underlying interactions between these environmental stressors (pharmaceuticals exposure and climate change) are still far from being fully understood. The aim of this study was to assess behavioural responses (in juvenile meagre (Argyrosomus regius) exposed to VFX via water ([VFX] ~20µgL-1) and via dietary sources ([VFX] ~160µgkg-1 dry weight), as well as to increased temperature (ΔT°C=+5°C) and high CO2 levels (ΔpCO2 ~1000µatm; equivalent to ΔpH=-0.4units). Overall, VFX bioaccumulation in fish plasma was enhanced under the combination of warming and acidification. VFX triggered fish exploration, whereas fish activity and shoal cohesion were reduced. Acidification alone decreased fish exploration and shoal cohesion, and reversed fish preference to turn leftwards compared to control conditions. Such alterations were further enhanced by VFX exposure. The combination of warming and acidification also reduced shoal cohesion and loss of lateralization, regardless of VFX exposure. The distinct behaviour observed when VFX contamination, acidification and warming acted alone or in combination highlighted the need to consider the likely interactive effects of seawater warming and acidification in future research regarding the toxicological aspects of chemical contaminants.