INTRO: Acoustic receivers were used to monitor over 100 individuals of sea trout in a southern Norwegian sea fjord. These receivers provide information on the habitat use of individual fish, and therefore enable the assessment of fish personality. The study investigated the role of external variables vs. individual identity in the survival of fish in their natural habitat.
MERITS: An interesting study on the scaling up of individual personality traits and their role in the survival of the fish.
CRITIQUE: Perhaps stating hypotheses more clearly in the abstract would make the abstract a little bit clearer. How do you think the different personalities may respond to different management strategies? Also, what are the main threats of the species in this area?
DISCUSSION: An interesting study, could be improved by a clearer statement of hypotheses, but unarguably there is only so much space in the abstract. Will the authors discuss the role of metabolism in this study, perhaps that could underlie the individual behavioural differences? (See for example Killen et al. (2015) Vulnerability of individual fish to capture by trawling is influenced by capacity for anaerobic metabolism. Proc R Soc B).
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INTRO: Authors of this study suggest that individual differences in personality may associate with sea performance in sea trout and hence the personality differences potentially cause survival consequences. They provide valuable information of the habitat usage of sea trout based on large scale telemetry data. Authors propose that the study of personality may help addressing the management methods accordingly since their results show personality differences in ecological gradient and management areas.
MERITS: I must acknowledge that the dataset in this study is very ambitious in revealing natural scale movement patterns in anadromous fish. Kudos to state of the art tracking methods, targeting these study questions is possible and I can easily understand authors' motivation for doing this study. They have used natural spatial and temporal scale that makes testing of personality-driven survival hypothesis meaningful.
CRITIQUE: I find that their ideas are there but need to be tied up in evolutionary context. I would like to hear the hypotheses behind the study such as which type of personality they expect to be selected in the certain habitat or under the management and why. At this point the abstract is missing a short justification, why range size and swimming depth are ecologically relevant factors to estimate the fish survival, would also be good additions. It is easy to understand that protection of the sea or fjord areas will benefit sea trout, but does it affect differently in different personalities i.e. does it only benefit certain personalities would be needed to discuss here.
DISCUSSION: The study described in this abstract has potentially great value, but in it's current state I find it a bit hard to follow. I reckon that authors will hit their target by simplifying the abstract and revisioning what they mean by personality differences. The attention to behavioural variation and its importance to species survival is increasing. Therefore, it would be interesting to see some discussion about what type of personalities will benefit the habitat protection and what may happen if these behavioural traits are selected in the wild (e.g. does protection potentially increase or decrease the home range and what will be the consequences in evolutionary perspective). Some brief introduction to behavioural conservation would help to tide this study in the eco-evolutionary context.
I would also like to comment that the uncertainty in analysing the fate of death of the fish could be reduced by comparing the capture-recapture data from non-tagged individuals to the data from tagged fish. By comparing these survival rates, it is possible to state whether the survival was "tagging" -dependent or not. I hope that they will be able to do this to increase the significance of the study.
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INTRO: Authors present rather ambitious project where large number of sea trout have been tracked with acoustic tags in Norwegian fjord. Aim was to investigate behaviour of individuals and link behavioural movement traits, and herein personality, to life history traits such as survival in order to assess to which degree personalities can affect fate of sea trout in the marine environment.
MERITS: Movement of aquatic animals is something we do not know much about as it is really difficult to study. Here inovative network of acoustic receivers in concise area is used to tackle interesting aspects of sea trout life history.
CRITIQUE: Study seems to be in early state, but I don't see this as a big problem.
DISCUSSION: Authors seem to provide infromation about potential protection benefits of the work for sea trout populations and more specifically the variation in obtained protection within the studied population. In general, such information is crucial for understanding the survival and protection of an anadromous species during their marine phase.
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INTRO: In this abstracts, authors discuss the relation between personality and survival of sea trout in a Norwegian fjord. The study plan is coherent and the setup using >100 tagged individuals in a dense accoustic receiver network seems adequate to answer these questions. The results shown here are only preliminary, but show interesting promises for future applications.
MERITS: The background, goals and focus of the study are well explained. The study question is of interest and could have important management and conservation implication for sea trout.
CRITIQUE: Some very fine-tuning of the language would be needed. For example :
L6: " in the horizontal and vertical plane" is a bit difficult to interpret to me.
DISCUSSION: The implication of this research can be very interesting and important for management purposes. I would be very interested to understand how personality affects survival, but also and probably even more, how personalities could affect the population response to protected areas.
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INTRO: This is highly interesting study and assays fish personality directly in natural setting giving it much relevance.
MERITS: This work has clearly a merit in being able to follow the behaviour of a large number of fish in their natural environment with direct possibility to estimate the survival costs and benefits for certain behavioural types.
CRITIQUE: The revision gives a chance to update the results if newer results are available now.
DISCUSSION: This is highly important research in natural setting with direct management conservation implications.
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INTRO: This part provides understandable framework for the study.
MERITS: The abstract provides information of interesting novel data on sea trout.
CRITIQUE: I did not identify any major weaknesses.
DISCUSSION: I judge that this work is quite important for the field as it helps us to understand how partial habitat protection may affect trout population that consists of differently migrating individuals.
