Ivonne Ortiz

• Doctor of Philosophy
• Researcher at University of Washington

Seasonal sea ice plays a key role in shaping the ecosystem dynamics of the eastern Bering Sea shelf. In particular, it leads to the formation of a characteristic pool of cold water that covers the bottom of the shelf from winter through summer; the extent of this cold pool is often used as a management index for distribution, productivity, recruitm...

North Pacific Marine Science Organization (PICES) Special Publication

Climate-related distribution shifts for marine species are, in general, amplified in northern latitudes. The objective of this study was to predict future distributions of commercially important species in the eastern Bering Sea under six climate scenarios, by incorporating predictions of future oceanographic conditions. We used species distributio...

The Bering Sea is a highly productive ecosystem, supporting a variety of fish, seabird, and marine mammal populations, as well as large commercial fisheries. Due to its unique shelf geometry and the presence of seasonal sea ice, the processes controlling productivity in the Bering Sea ecosystem span the pelagic water column, the benthic sea floor,...

Marine ecosystem forecasting is an area of active research and rapid development. Promise has been shown for skillful prediction of physical, biogeochemical, and ecological variables on a range of timescales, suggesting potential for forecasts to aid in the management of living marine resources and coastal communities. However, the mechanisms under...

Many coastal areas host rich marine ecosystems and are also centers of economic activities, including fishing, shipping and recreation. Due to the socioeconomic and ecological importance of these areas, predicting relevant indicators of the ecosystem state on sub-seasonal to interannual timescales is gaining increasing attention. Depending on the a...

The Bering Sea is a highly productive ecosystem, supporting a variety of fish, seabird, and marine mammal populations as well as large commercial fisheries. Due to its unique shelf geometry and the presence of seasonal sea ice, the processes controlling productivity in the Bering Sea ecosystem span the pelagic water column, the benthic sea floor, a...

A regional biophysical model is used to relate projected large-scale changes in atmospheric and oceanic conditions from CMIP5 to the finer-scale changes in the physical and biological structure of the Bering Sea, from the present through the end of the twenty-first century. A multivariate statistical method is used to analyse the results of a small...

We combined field data and the output from a climate-to-fish coupled biophysical model to calculate weekly climatologies and 1971-2009 time series of physical and biological drivers for 16 distinct regions of the eastern Bering Sea shelf and slope. We focus on spatial trends and physical-biological interactions as a framework to compare model outpu...

The composition of walleye pollock diets from the eastern Bering Sea continental shelf was determined from 25 years of sampling during summer surveys from 1987 through 2011. Substantial differences in the stomach contents of walleye pollock were found among the sizes and geographic strata that correspond to geographic distribution of the prey. With...

North Pacific Research Board Project Final Report

Projections of the impacts of climate change on marine ecosystems are a key prerequisite for the planning of adaptation strategies, yet are inevitably associated with uncertainty. Identifying, quantifying, and communicating this uncertainty is key to both evaluating the risk associated with a projection and building confidence in its robustness. We...

Traditionally, the advice provided to fishery managers has focused on the trade-offs between short- and long-term yields, and between future resource size and expected future catches. The harvest control rules that are used to provide management advice consequently relate catches to stock biomass levels expressed relative to reference biomass level...

Alaska Native coastal communities interact with the marine environment in many ways, especially through the harvest of fish, marine mammals, and seabirds. The spatial characteristics of this interaction are often depicted in terms of subsistence use areas: the places where harvests and associated travel occur. Another way to consider the interactio...

Mathematical modeling of marine food webs has been an area of active research in Alaska, particularly with respect to the fisheries management. Food web analyses have played a role in managing some single species fisheries, in estimating overall yields that may be sustainably extracted from ecosystems, and more recently in modeling and predicting f...

The aim of this paper is to identify and analyse policy frameworks that are important for facilitating adaptation to climate change impacts in coastal zones. The paper is based on a case study analysis of the Gulf of Mexico and examines two countries, the US and Mexico. It considers two climate change effects specific to coastal areas: sea level ri...

The goals of this research were to investigate geographic patterns in the Aleutian Island region's demersal ichthyofauna and to determine whether they reflected the physical and biological oceanographic patterns documented by other authors in this volume. The analyses were structured according to the level of organization: at the community level, p...

Thesis (Ph. D.)--University of Washington, 2007. Located between Asia and America and extending over a 1,000 mi., the Aleutian Islands have commonly been studied in a partial or fragmented manner. This dissertation presents the use of multiple spatial scales to distinguish between: (i) local and ecosystem-wide processes, and (ii) the ecosystem as d...