My research programme focuses on involving and mentoring undergraduate and postgraduate students in research. The four research themes we prioritise are:
Sustainable management of marine resources: an integrative approach to stock discrimination
Recent studies advocate an integrated approach to stock discrimination. The sensitivity of different stock discriminating tools may vary depending on temporal and spatial scale of sampling, and the ecology of the species of interest. We aim to compare the sensitivity of parasite communities (biological tags) in stock discrimination of commercial marine fishes relative to otolith-based and genetics/genomics approaches. Currently, I have two projects on this topic.
The first is a Study of the potential of parasites as biological tags for discriminating between cod (Gadus morhua) in Icelandic waters. The aims of this projects are to: (1) describe the complete parasite fauna and diet of cod samples collected from the North and South of Iceland in both shallow (<125 m) and deep (>250 m) waters; (2) examine the population structure using otolith shape, otolith microchemistry, and parasite communities, and validating assignment of ecotype using PanI locus; and (3) compare the efficacy of parasite communities at discriminating between cod ecotypes relative to the other methods. This project is funded through the University of Iceland Research Fund (grant number 15662) in collaboration with Christophe Pampoulie and Ingibjörg Jónsdóttir of the Marine and Freshwater Research Institute.
The second is on Blue whiting (Micromesistius poutassou) stock structure in the Northesaat Atlantic: one or many stocks? The aims of this project are to: (1) research blue whiting stock structure in the Northeast Atlantic Ocean using samples collected from west Greenland to the Barents Sea to the Mediterranean and clarify whether there are one or multiple stocks; (2) use an integrative approach to assess the potential of five different methods for stock identification, i.e. otolith shape, otolith microchemistry, parasite communities, gut microbiomes, and genomics, as a tool(s) for fisheries managers to discriminate between blue whiting stocks in the region; and (3) improve blue whiting stock assessment, prevent potential fishing to depletion of blue whiting stocks, and make sustainable harvesting goals for blue whiting more robust. This project is funded through the Icelandic Research Fund Rannís (grant number 239562-051 to Dr Brendon Lee) and NORA (grant number j.nr.510-221) in collaboration with Brendon Lee of the University of Iceland, Anna Heiða Ólafsdóttir of the Marine and Freshwater Research Institute, Jan Arge Jacobsen of the Faroe Marine Research Institute, Søren Post of the Greenland Institute of Natural Resources, Åge Høines of the Institute of Marine Research in Norway, and Patricia Goncalves of the Portuguese Institute for Sea and Atmosphere.
Parasites of skates in Icelandic waters.
Iceland is not considered by most as a biodiversity hotspot for elasmobranchs, yet 43 different species of cartilaginous fishes (22 species of sharks, 15 species of batoid skates, and 4 species of chimaerids) inhabit these waters. Very little is known about their parasite fauna with only 41 species belonging to 5 parasite groups being reported from cartilaginous fishes in Icelandic waters. Through a project titled: Conservation of ancient relationships: Assessment of skates (Rajiformes: Rajidae) and their parasite fauna in Iceland, we aim to survey the status of parasites infecting skates in waters surrounding Iceland to aid in the future implementation of conservation efforts of threatened host-parasite systems. The objectives of this project are to: (1) assess the diversity of parasites infecting skates in waters surrounding Iceland; (2) assess the genetic diversity of skate hosts and parasite lineages; and (3) evaluate the status of host-parasite systems based on IUCN Red List criteria. This project is funded through the Icelandic Research Fund Rannís (grant number 2410498-051) in collaboration with Bjoern Schaeffner of the Keldur Institute for Experimental Pathology and Peter Olson of the Natural History Museum in London, UK.
Parasites of marine fishes: providing ecological insights into trophic structure and dynamics.
Until recently, due to the cryptic nature of parasites, their relatively small size and assumed low biomass, they have generally been ignored in food web studies. In reality, species adopting parasitic lifestyles outnumber free-living ones and their biomass can exceed that of top predators in certain ecosystems. Knowledge of trophic interactions (i.e. transfer of energy from prey to predator) within an ecosystem provides clues identifying different transmission routes exploited by parasites that are transmitted through the food chain, such as tapeworms and roundworms. The presence of an adult worm in the gut of a predator and of larvae of the same species in a prey provides convincing evidence for a trophic interaction between both hosts. However, in marine ecosystems, our inability to accurately designate most larvae of tapeworms and other parasites to species, due to the lack of distinct morphological characters, impedes our efforts to elucidate the life cycles of these parasites and assess the epidemiology of disease or their ecological impacts on populations and communities. The advent of molecular tools has allowed us to circumvent the absence of distinctive morphological features in larvae and to address broader ecological questions such as how parasite transmission is affected by food web structure and whether parasites have adapted to exploit trophic links through which the bulk of energy is transferred up the food web as “transmission highways”.
Evolutionary processes shaping parasite evolution.
One of the major unresolved questions in evolution remains how parasites have made the transition from a free-living lifestyle. Parasitism has evolved independently many times throughout the tree of life and is the most common evolutionary transition in life history that we know of. Parasites account for up to half of the biodiversity of Earth and despite their ubiquity in a wide array of taxa, organisms shifting from a free-living existence to a parasitic one generally face similar selective pressures. For instance, regardless of their transmission strategy, parasites must optimise their transmission, evade the host’s immune response, and walk a fine line between high virulence and sustained host exploitation. The ecological paradigm within which we consider parasite evolution, proposes that all parasites converge towards six distinct life history strategies. The wide array of taxa in which parasitism has evolved towards a limited number of adaptive peaks (combination of traits that confer higher fitness and towards which all evolutionary trajectories eventually lead) suggests ecological constraints in the evolution of parasitism. For instance, a major adaptive peak for parasitism is trophic transmission, i.e. parasites requiring their host to be ingested to ensure successful transmission to the next host. Trophic transmission requires multiple hosts (intermediate and definitive hosts) for a parasite to successfully complete its life cycle (complex life cycles) and has evolved from direct transmission (simple life cycles). Most free-living organisms have simple life cycles, yet the majority of helminth parasites have evolved complex life cycles. Hence, there must be an adaptive origin for increased complexity in parasite transmission. It has been suggested that increased complexity provides an opportunity for growth (in intermediate hosts) and attaining larger body size (in definitive host) and therefore, greater fecundity. We aim to gain insights into trade-offs between specificity, life cycle complexity and fecundity in marine parasites.