18 research outputs found
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 newfound interest in animal personality among behavioural ecologists, fewstudies 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 maleâs 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 activityeboldness 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
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
Social equity is key to sustainable ocean governance
Calls to address social equity in ocean governance are expanding. Yet âequityâ is seldom clearly defined. Here we present a framework to support contextually-informed assessment of equity in ocean governance. Guiding questions include: (1) Where and (2) Why is equity being examined? (3) Equity for or amongst Whom? (4) What is being distributed? (5) When is equity considered? And (6) How do governance structures impact equity? The framework supports consistent operationalization of equity, challenges oversimplification, and allows evaluation of progress. It is a step toward securing the equitable ocean governance already reflected in national and international commitments
Fishing impacts on the trophic functioning of marine ecosystems, a comparative approach using trophodynamic models
Faced with the global overexploitation of marine resources and the rapid degradation of ecosystemsâ integrity, many states agreed to the principle of an ecosystem approach to fisheries (EAF). In fact, overfishing induces strong decrease of targeted species biomass, which impact predators, their competitors, prey, and ultimately the ecosystemsâ trophic networks. Thus, it is an important challenge to understand the trophic functioning of marine ecosystems and the related impacts of fisheries.
In this spirit, my thesis was developed to address concerns about the potential impacts of fisheries on the underlying trophic functioning, and to better understand this trophic functioning and its variability through ecosystems. Two well-known trophodynamic models were used : Ecopath with Ecosim (EwE) and EcoTroph (ET). First, I developed EcoBase, i.e., an online repository to gather and communicate information from EwE models, which enabled to give a global overview of the applications of the EwE modeling approach. Then, the ET model was corrected and standardized through the creation of a software package in R. A new trophic control, i.e., foraging arena (FA) trophic control, was integrated to study its impacts on trophic flows and fishing effects on aquatic ecosystem trophic networks. I showed that that making ecosystem behavior more realistic by incorporating FA controls into EcoTroph decreased the resistance and the production of modeled ecosystems facing increasing fishing mortality. An analysis of case studies focusing on marine protected areas (MPAs) was then performed using EwE and ET. I analyzed the potential spillover effect from three MPAs, and showed that their potential exports were at the same order of magnitude as the amount of catch that could have been obtained inside the reserve. Finally, a meta-analysis of marine ecosystem trophic functioning was conducted using 127 EwE models, which showed that ecosystem types were distinguished by different biomass trophic spectra and associated trophic indices. These differences were mainly driven by different production, but also kinetic for some ecosystem types. In conclusion, trophodynamic models, as EwE and ET, appeared to be useful tools to better understand the trophic functioning of marine ecosystems, its variability through ecosystems, and the associated impacts of fisheries.Science, Faculty ofZoology, Department ofGraduat
Fishing inside or outside? A case studies analysis of potential spillover effect from marine protected areas, using food web models
International audienceMarine protected areas (MPAs) are implemented worldwide as an efficient tool to preserve biodiversity and protect ecosystems. We used food web models (Ecopath and EcoTroph) to assess the ability of MPAs to reduce fishing impacts on targeted resources and to provide biomass exports for adjacent fisheries. Three coastal MPAs: Bonifacio and Port-Cros (Mediterranean Sea), and Bamboung (Senegalese coast), were used as case studies. Pre-existing related Ecopath models were homogenized and ecosystem characteristics were compared based on network indices and trophic spectra analyses. Using the EcoTroph model, we simulated different fishing mortality scenarios and assessed fishing impacts on the three ecosystems. Lastly, the potential biomass that could be exported from each MPA was estimated. Despite structural and functional trophic differences, the three MPAs showed similar patterns of resistance to simulated fishing mortalities, with the Bonifacio case study exhibiting the highest potential catches and a slightly inferior resistance to fishing. We also show that the potential exports from our small size MPAs are limited and thus may only benefit local fishing activities. Based on simulations, their potential exports were estimated to be at the same order of magnitude as the amount of catch that could have been obtained inside the reserve. In Port Cros, the ban of fishing inside MPA could actually allow for improved catch yields outside the MPA due to biomass exports. This was not the case for the Bonifacio site, as its potential exports were too low to offset catch losses. This insight suggests the need for MPA networks and/or sufficiently large MPAs to effectively protect juveniles and adults and provide important exports. Finally, we discuss the effects of MPAs on fisheries that were not considered in food web models, and conclude by suggesting possible improvements in the analysis of MPA efficienc
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, CollĂ©ter 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 worldâs 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
Fisheries Centre Research Reports, Vol. 21, No. 1
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. 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.Science, Faculty ofNon UBCOceans and Fisheries, Institute for theUnreviewedFacultyPostdoctoralGraduateUnknow
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Who Gets the Catch? How Conventional Catch Attribution Frameworks Undermine Equity in Transboundary Fisheries
The focus on flag States for the purpose of attributing fisheries catch is inconsistent with the assignment of sovereign rights to coastal States under international law and undermines equity in contemporary quota allocation negotiations. We propose modernizing reporting frameworks to include zone-based reporting of fish catches to more equitably present data, ensure consistency with the Law of the Sea, and better support the realization by developing coastal States of their development aspirations consistent with SDG 14, Life Below Water. States are already required to collect the data necessary to support this change, and many regional fisheries management authorities already do so. Reforms to data collection and reporting mechanisms should support zone-based catch attribution as a central feature of negotiations around access to future fishing opportunities on shared resources. Doing so will ensure that the sovereign rights of developing coastal States are properly accounted for and implemented
TCI and ECI trends on an a priori selection of LMEs.
<p>(a) Time indicator nominal values trends (b) Efficiency indicator nominal values trendsââGroup 1â gathers the 10 most strongly exploited ecosystems (according to their SSPs); âGroup 2â gathers the 10 ecosystems with the strongest increase in SST since 1990; âAll LMEsâ gathers the 56 LMEs. Colored sectors refer to bootstrap confidence intervals of the mean, at 95%.</p