I carried out my undergraduate studies at the University of Lisbon (Portugal) and afterwards my Masters degree and PhD at the Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO) of the University of Porto (Portugal). During my PhD I studied the impact of the geological and climatic history of the Atlantic Ocean and Mediterranean Sea on the evolution of a group of marine isopoda (Genus Stenosoma), using molecular tools. I joined CRIPES in 2011 when I was awarded a post-doctoral grant to work with Dr Jo Cable to investigate host-parasite interactions and parasite spill-over between fish hosts using a phylogenetic framework. In open marine and freshwaters habitats, fish can easily come into contact with new parasites, often compromising their fitness. In addition, most aquatic environments are heavily affected by anthropogenic pressures leading, for example, to habitat degradation. Environmental stressors, such as pollution and climate warming, may induce changes in parasite prevalence and may even influence the diversity of parasite communities. Evaluating levels of parasite spill-over, as well as identifying which factors contribute to the emergence of diseases is paramount, especially when hosts are used for human consumption. Moreover, this knowledge can be used to improve conservation and habitat management measures.
Position: Post-Doctoral researcher
Telephone: +35 1252660411
Location: CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, R. Padre Armando Quintas, 4485-661 Vairão, Portugal
Since 2012 I have been working in collaboration with Prof. Jo Cable, Dr. Benoit Goossens, and Cardiff student Mike Reynolds in uncovering the parasite diversity of commercially valuable fish hosts, from the Kinabatangan River, Borneo. Ecosystems in this area are being greatly affected by encroaching oil palm plantations, which are responsible for pollution and habitat disturbance. Our main aims are to quantify parasite diversity and understand the effects of pollution and habitat degradation in parasite communities from this region. This is particularly important as local communities rely on fish for food and fishing for subsistence.
Additionally, I am running a project in Portugal aiming at using an integrative approach to investigate the consequences of pathogen spill-over between wild and farmed fish species in the Alvor Estuary. This estuary is an important nursery for many native species that has been designated a Natura 2000 site. Aquaculture is one of the fastest growing industries worldwide, levered both by an increasing demand for fish food and the current awareness about the over-exploitation of wild fish stocks. Parasitic diseases cause significant impacts on fisheries and aquaculture production by inducing high levels of fish mortality. Fish farming conditions are known to affect parasite evolution causing the emergence of more virulent strains. Moreover, stressful conditions imposed by farming can reduce fish immunocompetence, favouring the spread of pathogenic infections. Parasite spill-over from farmed to wild fish populations is not uncommon and has been responsible for the emergence of diseases in many wild populations. Changes in parasite host-range and host-switching events, i.e. the infection of new hosts, are known to drive parasite speciation, and to cause severe impacts on ecosystems by affecting host diversity and altering entire food web dynamics. Our aims with this project are to investigate whether: 1) parasite host-switching is occurring between wild and farmed fishes; 2) farmed fishes are acting as reservoirs of diseases for the native fish fauna; 3) host-switching is promoting parasite speciation; and 4) host-switching is prompting the emergence of more virulent parasite strains. This project is financed by the Fundação para a Ciência e Tecnologia (FCT).
Cabezas M.P., Xavier R., Branco M., Santos A.M., Guerra-García J.M. (2014). Invasion history of Caprella scaura Templeton, 1836 (Amphipoda: Caprellidae) in the Iberian Peninsula: multiple introductions revealed by mitochondrial sequence data. Biological Invasions 16 (10): 2221-2245. http://doi.org/10.1007/s10530-014-0660-y
Xavier R., Severino R., Pérez-Losada M., Cable J., Harris D.J. (2013). First record of Sphaerospora dicentrarchi (Myxosporea, Sphaerosporidae) in Dicentrarchus punctatus. Bulletin of the European Association of Fish Pathologists 33: 21-24.
van Oosterhout C., Mohammed R.S., Xavier R., Stephenson J.F., Archard G.A., Hockley F.A., Perkins S.E., Cable J. (2013). Invasive freshwater snails provide resource for native hermit crabs. Aquatic Invasions 8: 185-191 http://dx.doi.org/10.3391/ai.2013.8.2.06
Sousa L.L., Seabra R., Wethey D.S., Xavier R., Queiroz N., Zenboudji S., Lima F.P. (2012). Fate of a climate-driven colonization: demography of newly established populations of the limpet Patella rustica Linnaeus, 1758, in northern Portugal. Journal of Experimental Marine Biology and Ecology 438: 68-75. http://dx.doi.org/10.1016/j.jembe.2012.09.005
Xavier R., Santos A.M., Branco M. (2012). MtDNA and nuclear data reveal patterns of low genetic differentiation for the two isopods, Stenosoma lancifer and Stenosoma acuminatum, with low dispersal ability along the Northeast Atlantic coast. Scientia Marina 76: 133-140. http://dx.doi.org/10.3989/scimar.03373.29A
Xavier R., Santos A.M., Harris D.J., Sezguin M., Zenboudji S., Branco M. (2012). Phylogenetic analysis of Stenosoma (Isopoda: Idoteidae) species in the Atlantic and the Mediterranean. Zoological Scripta 41: 386-399. http://10.1111/j.1463-6409.2012.00537.x
Santos A.M., Xavier R., Zenboudji S., Branco T., Branco M. (2011). Stenosoma stephenseni (Isopoda, Idoteidae), a new species from the SW Mediterranean and Alboran Sea, with a note on the nomenclatural status of the genus name Synisoma Collinge, 1917. Zookeys 141: 29-44 http://dx.doi.org/10.3897/zookeys.141.1376
Xavier R., Zenboudji S., Santos A.M., Harris D.J., Lima F.P., Branco M. (2011). Phylogeography of the marine isopod Stenosoma nadejda (Rezig, 1989) in North African Atlantic and western Mediterranean coasts reveals complex differentiation patterns and a new species. Biological Journal of the Linnean Society 104:419–431 http://dx.doi.org/10.1111/j.1095-8312.2011.01718.x
Xavier R., Lima F.P., Santos A.M. (2010). Forecasting the poleward range expansion of an intertidal species driven by climate alterations. Scientia Marina 74: 669-676. http://dx.doi.org/10.3989/scimar.2010.74n4669
Lima F.P., Queiroz N., Ribeiro P.A., Xavier R., Hawkins S.J., Santos A.M. (2009). First record of Halidrys siliquosa (Linnaeus) Lyngbye in the Portuguese coast: counter-intuitive range expansion? JMBA2 – Marine Biodiversity Records 2:e2. http://dx.doi.org/10.1017/S1755267208000018
Ribeiro P.A., Xavier R., Santos A.M., Hawkins S.J. (2009). Reproductive cycles of four species of Patella on the northern and central Portuguese coast. Journal of the Marine Biological Association of the United Kingdom 89: 1215-1221. http://dx.doi.org/10.1017/S0025315409000320
Xavier R., Santos A.M., Lima F.P., Branco M. (2009). Invasion or invisibility: using genetic and distributional data to investigate the alien or indigenous status of the Atlantic populations of the peracarid isopod, Stenosoma nadejda (Rezig 1989). Molecular Ecology 18: 3283–3290 http://dx.doi.org/10.1111/j.1365-294X.2009.04260.x
Lima F.P., Ribeiro P.A., Queiroz N., Xavier R., Tarroso P., Hawkins S.J., Santos A.M. (2007). Modelling past and present geographical distribution of the marine gastropod Patella rustica as a tool for exploring responses to environmental change. Global Change Biology 13: 2065-2077. http://dx.doi.org/10.1111/j.1365-2486.2007.01424.x
Xavier R., Barata A., Cortez L.P., Queiroz N., Cuevas E. (2006). Hawksbill turtle (Eretmochelys imbricata Linnaeus 1766) and green turtle (Chelonia mydas Linnaeus 1754) nesting activity (2002-2004) at El Cuyo beach, Mexico. Amphibia-Reptilia 27: 539-547 http://dx.doi.org/10.1163/156853806778877077
Queiroz N., Araújo S., Ribeiro P.A., Tarroso P., Xavier R., Santos A.M. (2006). A first record of longfin mako, Isurus paucus, in the mid-North Atlantic. JMBA2 – Biodiversity Records 1:e34. http://dx.doi.org/10.1017/S1755267206003484