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Sonia Ibarra

Ph.D. Student


Juneau, Alaska



Humboldt State University
B.S. Marine Biology





Pirtle, J.L., S.N. Ibarra, and G.L. Eckert. 2012. Nearshore subtidal community structure compared between inner coast and outer coast sites in Southeast Alaska. Polar Biology 35(12): 1889–1910.



  • Subtidal biological sampling


Research Overview

My research focuses on the impacts of sea otter recolonization on kelp communities throughout southern Southeast Alaska using an interdisciplinary approach. Sea otters were exterminated during the 19th century fur trade, and their populations are now rebounding, as a result of reintroductions in the 1960’s. This result suggests that there is hope that apex consumers can recover, yet new resource conflicts between humans and sea otters makes their future uncertain once again. Can humans and apex consumers coexist? Finding sustainable solutions to the otter impact on commercial, sport and subsistence fisheries is in its infancy and by integrating an interdisciplinary ecosystem-based approach, holistic solutions will better serve humans and otters alike. In addition to conducting biological surveys my work will integrate traditional knowledge of local communities to identify ecosystem services derived from the marine environment and tradeoffs with otter presence and absence. By using a tool similar to InVEST, data derived from field observations, local knowledge, analytical information from statistical analyses and conceptual models, we will be able to valuate ecosystem services and tradeoffs across various spatial scales. These results will have direct application to commercial, sport and subsistence fishing industries. With the future of commercially valuable marine invertebrates stocks uncertain, our project will provide valuable information on the potential future outcome of these stocks in respect to southeast Alaska’s expanding sea otter population.


Current Research Projects

  • Integrate and valuate ecosystem services and tradeoffs across scales. Using input values drawn from stakeholders, analytical information from ecological studies and conceptual models we will valuate ecosystem goods and services derived in each otter habitation treatment using a program called InVest.
  • Evaluate the sustainability of coastal communities along a spectrum of sea otter habitation. Study objectives: Identify sea otter impacts on subsistence resources and human use
  • Identify differential spatial impacts of sea otter presence on subsistence resources
  • Identify temporal changes in sea otter distribution from time of introduction
  • Identify temporal impacts on subsistence resources in different locations
  • Estimate impact of sea otter on subsistence harvests of different resources. Research methods used to acquire the data include literature reviews, local ecological knowledge interviews, mapping, structured questionnaires, and on-site visitations with knowledgeable subsistence users to locations of sea otter presence.
  • Document marine ecosystem structure in southern Southeast Alaska along a gradient of sea otter habitation using SCUBA survey techniques. We will conduct ecological studies in each of four sea otter population ‘treatments’, to include areas (1) with no sea otters, (2) recently colonized 3-10 years, (3) established 10-20 years and (4) established greater than 20 years (Figure 2). Eight ‘sites’ along 2 km of coastline will be sampled over two years in each of the four sea otter treatments. Within each site, four replicate samples will be taken for each of the parameters of interest.



  • UAF Marine Ecosystem Sustainability in the Arctic and Subarctic Fellowship Program
  • National Science Foundation Graduate Research Fellowship Program
  • Minority Striving and Pursuing Higher Degrees in the Earth Sciences Fellowship