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Pace of life syndromes in fish: harvesting effects and the role of marine reserves

Final Report Summary - BE-FISH (Pace of life syndromes in fish: harvesting effects and the role of marine reserves)

Project objectives
BEFISH project, “Pace of life syndromes in fish: harvesting effects and the role of marine protected areas” (www.befishproject.wordpress.com) run from May 2014 to April 2016. The objective of BEFISH, as stated in the proposal document, where:
1. Objective 1: evaluate the existence of individual behavioural syndromes including behavioural traits measured both in the wild (Olsen et al., 2012 has shown that some behavioural differences actually exist) and in laboratory/mesoscale conditions, which has rarely been assessed. We will assess if behavioural differences between individuals are consistent over time and if they are correlated across different situations and contexts.
2. Objective 2: understand the correlation between the behavioural traits addressed in objective 1 and life-history and physiology traits at the individual level. The objective is to test some of the predictions by Réale et al (2010) who established the expected correlations between behavioural, life-history and physiological traits in the context of pace of life syndromes.
3. Objective 3: investigate if human harvesting is selective on some behavioural traits and investigate the role of marine reserves (phenotypic buffers vs. new evolutionary forces) in the context of pace of life syndromes, resource productivity and sustainability.

Work done since the beginning of the project
The project started with capturing cod individuals from the wild. For that we set eel pots in Tvedestrand fjord in two seasons: spring and autumn 2014. Individuals were transported to the facilities of the Institute of Marine Research in Flødevigen. Once there, they were subject to behavioral assays the scores their personality. We conducted several replicates of three different tests to each fish to measure their boldness, aggressiveness and exploratory tendency. Then, we sampled the individuals for life-history traits: body size and weight and scales. Last, we implanted a telemetry transmitter inside the body cavity using standard surgical techniques.
All fish were then released back to the fjord where a network of 51 hydroacustic receivers was previously installed to be able to detect the fish. Fish individuals were tracked for more than one year. During that period the network of receivers was frequently visited to download data and for maintenance.
Data analysis consisted of three main work packages. First, we analyzed data from the videos recorded during the captive behavioral assays. From each assay we extracted some variables that gave us information about the behavioral tendency of the individuals. Then, mixed model were used to detect predictors of personality (e.g. body size, time of the year), and to estimate repeatability (personality) and correlations among traits (behavioral syndromes). Second, we analyzed an existing data set on wild behavior using mixed model to investigate repeatability of wild behavior and correlations among wild traits. This allowed us to detect personality behavior in the wild and behavioral syndromes. Last, we analyzed the telemetry data from the fish that we tagged (and that were previously subject to behavioral assays) and investigated the correlation between captive personality and wild spatial traits, as a function of environmental variables (sea surface temperature).

Main results achieved so far
The main results of the project can be summarized in.
- We found that cod can be assessed for personality traits like boldness, exploration and aggressiveness using standard assays normally used with small model species.
- Personality scores of boldness, aggressiveness and exploration were highly correlated meaning that individuals can be scored into a reactive-proactive axis. Reactive fish are shy, little explorer and little aggressive, whereas proactive fish are the opposite.
- Cod individual showed a great variation in their spatial behavior in the wild, specifically in terms of home range, diel vertical migration, vertical and horizontal activity and use of the water column.
- Cod displayed consistent individual behavior in the wild. This mean that some fish have, for instance, larger home range that others once the effect of body size, season, year and others is accounted for. This can be considered personality behavior in the wild.
- Behavior displayed in the wild is correlated and structured into behavioral syndromes, but these syndromes vary depending on the population and the local conditions
- Personality as measured in captivity predicts behavioral response to temperature and survival in the wild. Proactive fish don’t change their general activity as water warms up, but reactives do. Proactive fish have a lower survival than reactive fish.

Impact
The impact of the project is evidenced by the novelty of the results. BEFISH will:
- Change the way we view and analyze telemetry data. We have shown the ability of this kind of data to understand eco-evolutionary processes, something rarely done to date.
- Increase our awareness about the potential for fisheries induced evolution on behavioral traits. Previous research showed selection on behavior, but we are among the first to show that those behaviors subject to selection are repeatable (and thus likely heritable) and correlated, which can bring about correlational selection processes.
- Produce new theory and hypothesis. One of our results is an opinion challenge that challenges how we view marine protected areas and their effects. Similarly, the fact that we found personality-dependent reaction norms in the wild is completely novel and will seed new project and publication on the topic.
- In general, BEFISH has looked into the eco-evolutionary consequences of individual behavior. As such, it has unrevealed important patterns and processes of behavioral consistency and variation that will deserve further research in the coming future.