December 16, 2016
I am looking to recruit two post-docs to work on two Department of Fisheries and Oceans Canada (DFO) projects in the Maritimes that include the development of EwE models, including Ecospace, to further both EBM in the Maritimes and explore the potential impacts of climate change from an ecosystem perspective. If you know of any PhD students that are about to finish, or that have recently graduated that have the relevant expertise, please forward this email to them and ask them to contact me (firstname.lastname@example.org).
Two brief descriptions are provided below. I already have funding for the first, and I am seeking funding for the second, which is part of a larger DFO project.
- Assessing management options for vulnerable species in an ecosystem context
Marine ecosystems are dynamic networks of interacting species, subject to a range of pressures, of which fishing has been the dominant pressure in the Maritime Region. Fishing has shaped the marine ecosystem of the Scotian Shelf, and climate change is forecast to do the same. Guenette et al (2014), using an ecosystem model, forecast that climate change was likely to lead to reductions of around 20% of ecosystem biomass on the western Scotian Shelf and Bay of Fundy. In a separate analysis, Stortini et al (2015), using a “Vulnerability to Projected Warming Assessment” found that marine species in the south west of the Scotian Shelf, were more vulnerable to climate change than species on the eastern Scotian Shelf. At the same time, several key fish species in the western Scotian Shelf and Bay of Fundy are also highly vulnerable due to their low biomass and reduced age structure, largely due to high fishing mortality. Guenette et al (2014) concluded that the projected declines in biomass due to climate drivers “could be alleviated in part by a 50% decrease in exploitation rate”. This project proposes to explore possible management options for key vulnerable species on the western Scotian Shelf and Bay of Fundy using an ecosystem approach. Species identified by Stortini et al (2015) will be placed in an ecosystem context and modelled using Ecopath with Ecosim and Ecospace (Guenette et al 2014, Araújo et al. 2012). The model will be driven by downscaled projections of climate change and different management options for key vulnerable species.
This is a one-year project with the potential to be extended to two years.
- An Ecosystem-Based Stock Assessment Approach to Improve Operational Fisheries Science Advice
Environmental and biological community variability (defined here as “ecosystem factors”) has not been integrated into the majority of stock assessments in the Maritimes region, despite the sensitivity of fish stocks to changes in environmental conditions and predator-prey communities. To date, integration of ecosystem factors into stock assessments has largely been done on an ad-hoc basis, in only a few assessments (Bundy et al. 2012, Choi et al. 2013, Hardie et al. 2015). As a result, scientific advice for decision making may be based on analyses that ignore ecosystem factors which influence population parameters at short (interannual), medium (several years), or longer time scales, resulting in greater uncertainty in the quality of advice provided to managers. The need to consider ecosystem factors in stock assessments is acute, since Maritimes ocean and plankton conditions have shifted in recent years to a state associated with lower productivity conditions (Hebert et al. 2016, Johnson et al. 2016), which will have impacts throughout the ecosystem.
Ecosystem, fish and invertebrate community trends
Temporal trends in the dynamics of ecological communities and functional groups do not inherently exhibit the same levels of variability as are observed in single species, due to the interplay of individual species abundances and their functional roles in community structure. Estimating system productivity at a multispecies or functional group level typically results in lower levels of population growth rates and total system carrying capacity when compared to the sum of individual species productivity estimates (Fogarty et al. 2012). It is therefore important to consider the role of community composition and species interactions in single species stock assessments. Incorporating multispecies and community metrics into stock assessment advice, development of reference points, and harvest control rules will provide the ecosystem context and potential consequences of different harvest strategies.
Ecosystem, fish, and invertebrate community status will be assessed in two ways: through scorecard-type visualization and analysis of normalized stock biomass anomalies from multiple surveys, and through model-based analyses using Ecopath with Ecosim (EwE). In year 1, scorecard assessments of dominant patterns of community composition and their response to changes in bottom up (e.g, plankton) and top down drivers (e.g., fishing, predation) will be evaluated for the eastern and western Scotian Shelves (ESS, WSS), providing ecosystem context for inclusion in single species stock assessments. The EwE model for the ESS will be updated in year 1 (Bundy 2004), while the WSS EwE model will be updated through an ACCASP project. In year 2, the EwE models will be used to estimate total system productivity, catch limits, and interaction strengths, to compare system productivity to estimates from fisheries production potential models (NAFO 2013), and to compare single species reference points with multispecies reference points, contributing to a precautionary approach.
This is a 2 year project.
For more information, contact:
Research Scientist, Ocean Ecosystem Science Division,
Fisheries and Oceans Canada
Bedford Institute of Oceanography,
PO Box 1006, Dartmouth, NS B2Y 4A2, Canada.
Tel: + 902 426 8353, Fax:+902 426 1506