TRansfers of Anthropogenic and Natural Stressors Involving Trophic Interactions of Ocean Nekton (TRANSITION).

PAstners: IIM-CSIC e Instituto Español de Oceanografia

Principal Investigator IIM: G. Pierce

Funding: Ministerio de Ciencia, Innovación y Universidades

Budget: 153 700 €

Start: 2019

End: 2021

The overall objective of the project is to model the transfer via marine food webs, of stressors of anthropogenic and natural origin and their impacts, in the Northwest Iberian Peninsula. The project will focus on three types of stressors, parasites (especially the zoonotic nematodes Anisakis spp.), contaminants (focused on persistent organic pollutants (POPs)) and pathogens (focused on Brucella and morbillivirus in cetaceans), while considering the broader context of pressures such as fishing and climate change. Trophic links in the ecosystem will be considered in terms of both benefits (energy transfer) and costs (stressor transfer), and in relation to (1) their cumulative effects on individual life history, via food intake, from effects on growth, maturation condition and health to consequences for survival and fecundity, (2) consequences for population dynamics and (3) effects on ecosystem function. The project builds on an ecosystem model of intermediate complexity constructed using GADGET, originally for hake assessment and latterly modified to investigate interactions involving hake, common dolphin and bottlenose dolphin. The inclusion of stressors and individual level impacts in an ecosystem model is novel and is expected to provide a different perspective on the health and resilience of populations and ecosystems. The project will collect and analyse new samples and data on hake and dolphins, and assemble historical data on these species plus blue whiting and sardine. It will analyse relationships between different individual life-history parameters, and between diet, stressors, individual and population parameters, based on empirical statistical relationships and simple mathematical representations. Comparisons between individuals of different sizes and ages will be used to infer the time course of bioaccumulation of pollutants and parasites and hence the trajectories of resultant impacts. At the population level, impacts of fishing, climate and density-dependence will also be considered. Results will be used to construct an ecosystem model using GADGET, based on the existing GADGET models. The project will provide new information on pollutant concentration and Anisakis infections in fish and cetaceans and the role of these stressors in determining condition and reproductive output. It will provide insights into the incidence and impacts of Brucella and morbillivirus in dolphins. Analysis and modelling results will improve our understanding of abundance trends and will allow us to run scenarios of current and hypothetical fishing and climate regimes, predicting likely outcomes for abundance of commercially fished and protected species, the abundance of Anisakis, ecosystem resilience, sustainability of fishing and the implications for food safety in the seafood value chain. The core team of the project includes three researchers from IIM CSIC and IEO, supported by an extensive multidisciplinary group of collaborators from within these institutes, other Spanish and overseas institutes and a Spanish NGO, providing additional expertise, access to relevant data and samples, and carrying out specific analyses on behalf of the project (e.g. analysis of POPs, stable isotopes, Brucella and morbillivirus).