Mathieu Colléter

Personality traits predict hierarchy rank in male rainbowfish social groups

Personality traits are becoming increasingly important in explaining adaptive individual differences in animal behaviour and probably represent a leading edge of the evolutionary process. Despite the new-found interest in animal personality among behavioural ecologists, few studies have investigated the link between personality traits and fitness measures. We examined this link using male rainbowfish, Melanotaenia duboulayi, as a model species and found that a range of personality traits (aggression, activity and boldness) covaried with a male’s position in a hierarchy, which is directly related to reproductive success in this and many other species. Dominant fish were more aggressive, active, bold and also significantly larger than subordinate fish. Moreover, we found strong correlations between activity levels and boldness suggesting that selection may act on a suite of traits in concert (sensu behavioural syndromes). When taken together with previous research, our results suggest that the activity–boldness syndrome is likely to be domain specific. We suggest that multiple trait correlations may be generated by high levels of competition (e.g. sexual selection) in addition to predation pressure as identified by previous studies.

EcoBasE: a rEpository solution to gathEr and communicatE information from EwE modEls

It is now clear that research addressed at a large scale can allow for new insights on complex phenomena taking place in the global ocean. Ecological studies are more and more based on data-driven methodologies that rely on pre-existing datasets. However, open-access, digital and cross-disciplinary datasets are still uncommon for ecology. In the face of the global overexploitation of marine resources and rapid degradation of ecosystem integrity, new research tools are required to tackle these issues and enable new powerful, interdisciplinary research capabilities. We have, in fisheries research generally, and at the Fisheries Centre in particular, broad experience with fisheries data collection, and analysis of food web aspects of ecosystem dynamics. With this report titled EcoBase: a repository solution to gather and communicate information from EwE models, Colleter and colleagues have made a big effort at collecting information from all existing ecosystem models worldwide, built using the Ecopath with Ecosim (EwE) approach. EwE is the world’s most widely used ecological modeling approach, and its development is led by Fisheries Centre researchers, including, Villy Christensen, Daniel Pauly and Carl Walters. A new accomplishment is now achieved with the EcoBase project initiated by the Ecopath Research and Development Consortium (ERDC) and carried out by the authors of this report. The ERDC was initiated at the Fisheries Centre in October 2011, and formally established in Edinburgh, Scotland, in May 2012. It contributes to creating synergies and partnerships between scientists in aquatic ecology, and promotes the EwE modeling approach. The main goals of EcoBase are to (i) gather published EwE models; (ii) communicate on EwE modeling research; (iii) facilitate meta-analyses based on EwE models. EcoBase is meant to be a comprehensive, open-access, digital repository where EwE models are made discoverable, accessible and reusable by the scientific community. The structure, capabilities and current state of the EcoBase models repository are described in further details in this report. This represents new opportunities for research and trans-disciplinary analyses, including, trophic functioning, fisheries impact or economic aspects, for which I commend the authors. U. R. Sumaila, Director, Fisheries Centre, UBC.

Global change in the trophic functioning of marine food webs

The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI) measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI) quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950–2010 time-periods. Global trends were identified and cluster analyses were used to characterize the variability of trends between ecosystems. Results showed that the most common pattern over the study period is a global decrease in TCI, while the ECI indicator tends to increase. Thus, changes in species assemblages would induce faster and apparently more efficient biomass transfers in marine food webs. Results also suggested that the main driver of change over that period had been the large increase in fishing pressure. The largest changes occurred in ecosystems where ‘fishing down the marine food web’ are most intensive.