Browsing College of Fisheries and Ocean Sciences (CFOS) by Subject "whitefishes"
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The seasonal dynamics of coastal Arctic lagoons in Northwest AlaskaLagoons are zones of habitat transitions between freshwater and marine ecosystems, providing safe and productive feeding habitats for whitefishes in Northwest Alaska, important to subsistence users in the region. However, many important lagoon processes are not understood. Therefore, the goal of this thesis was to gain a baseline understanding of two important seasonal processes of lagoons in Northwest Alaska. First, I attempted to identify environmental processes correlated with Arctic lagoon breaching for three indicator lagoons that represent a range of environmental characteristics using generalized linear models (GLM) in an information theoretic approach and model averaging. Second, I developed a habitat suitability (HS) model to identify the range of physical conditions that whitefishes may experience if overwintering under ice of these lagoons during the Arctic winter, for the same three lagoons. The GLM model suggested that lagoon breaching day of year was slightly negatively related to day of year of river break-up, but other unconditional confidence intervals for the covariate parameters overlapped zero indicating considerable uncertainty in these estimates. Further data collection and monitoring in the region is needed to improve and verify lagoon breaching modelling results. The HS model indicated that lagoons have reduced suitability as whitefish habitat in winter due to loss of habitat due to the presence of bottomfast ice and a reduction of liquid water quality due to cold temperatures, high salinities and low dissolved oxygen levels. Importantly, small lagoons without freshwater inputs were potential sinks for fish populations. The results from this research will help the National Park Service and the Native Village of Kotzebue in a joint effort to understand and manage these important habitats that are critical for subsistence fisheries as the Arctic faces an uncertain future with climate change, oil spill threats, and increased coastal development.
Traditional knowledge and fish biology: a study of Bering cisco in the Yukon River Delta, AlaskaRelatively little is known about the biology of whitefishes (subfamily Coregoninae) in Alaska. To address this shortcoming, I combined social and biological science methods to examine whitefish in the Yukon River delta, Alaska. This study had two objectives: (1) to collaborate with Yup'ik subsistence fishers in sharing their knowledge of whitefish; and (2) to describe the life history of Bering cisco Coregonus laurettae. In August 2004, interview participants discussed Yup'ik traditional knowledge of whitefish. Participants shared knowledge of Bering cisco and other whitefish species. Interviews demonstrated the need for greater awareness of traditional knowledge, and the importance of communicating this knowledge with scientists. In addition, 120 Bering ciscoes were collected in August 2005 and 2006 with gill nets in the Yukon River delta, Alaska. Bering ciscoes ranged in fork length from 146 to 490 mm (mean = 321 mm) and in weight from 32 to 735 g (mean = 304 g). Fish ranged in age from 0 to 6, with one age-11 individual observed. Diet analysis showed that Bering ciscoes fed primarily on sticklebacks. My study records important social and biological data regarding Bering cisco, linking ethnography and fish biology as a means of investigating this poorly understood species.