Title
Coastal Lagoon Monitoring in the Southern Chukchi Sea National Park Units: Fieldwork Summary 2018
Author(s)
Beatrice Smith; Martin Robards; Marguerite Tibbles
Published
2019
Abstract
Wildlife Conservation Society (WCS) works with the National Park Service to design and implement the Coastal Lagoon Vital Sign component of the Inventory and Monitoring Program. This program is intended to establish biotic and abiotic reference conditions for assessing long-term changes in the coastal lagoons of Cape Krusenstern National Monument and Bering Land Bridge National Preserve. The vital signs program focuses on monitoring both the structure and ecological function of lagoons, as well as the fish resources used for subsistence by coastal communities. A standardized Vital Sign Protocol was developed for these coastal lagoons, informed by our field efforts throughout 2015, 2016, and 2017. Our 2018 vital sign field efforts, supplemented by funding from the National Park Foundation in support of a project called “Kotzebue Sound Whitefish Ecology and Seasonal Dynamics,” sought to build upon the pre-existing database of in-depth temporal and spatial information on lagoon ecology. There are nine coastal lagoons described in the boundary of Cape Krusenstern National Monument – Aukulak, Imik, Ipiavik, Kotlik, Krusenstern, Port, Sisualik, Tasaycheck, and Atilagauraq. We collected seasonal physical and biological data at three Cape Krusenstern lagoons including Kotlik, Krusenstern and Aukulak. We collected information of physciochemcal water properties and performed zooplankton community sampling as well a primary productivity assessment at all three lagoons. We sampled community composition, seasonal and spatial patterns of lagoon use, trophic dynamics, and fish health taking otolith, fin clip samples and muscle plugs from captured specimens. Additionally, we conducted sampling in the Tukrok River, a marsh and riverine matrix which acts as the connection between Krusenstern Lagoon and the Chukchi Sea, with the outlet to the marine environment located 15 km away from the main body of the lagoon. Given the significant distance between the two sampling locations we treated the Tukrok channel as an entirely different sampling site than Krusenstern lagoon. While ease of access and logistics allowed for frequent sampling at Cape Krusenstern, the need for floats (unavailable locally so cost preclusive) or a helicopter (no permits approved from Bering Land Bridge) prevented sampling effort at the Bering Land Bridge lagoons during the 2018 field season. We generally accessed the various Park unit lagoons via fixed-wing plane equipped with tundra tires. Within each visited lagoon, we used a small inflatable boat equipped with a 9.9 horsepower outboard motor. Four long-term (Center, Outflow, Inflow, and Adjacent-to-the-Ocean stations) and three random sampling stations where sampled at each lagoon. At each station we collected data on primary productivity (YSI Sonde instrumentation) and fish population (beach seine, fyke net, gillnet, minnow trap). Additionally, certain stations were sampled for zooplankton abundance (Wisconsin plankton tow net), while opportunistic observations of avifauna and animal communities surrounding the lagoons were collected when possible. Preliminary results from data gathered during the 2018 field season are synthesized in this report. The data compiled in this report reflect findings from sample efforts which included a total of 7 beach seine sets, 4 fyke net sets and 40 gillnet sets. These will supplement results from in-depth laboratory analyses of zooplankton and fish samples in collaboration with the University of Alaska, Fairbanks and Juneau. Lagoons vary in their seasonal connectivity with the ocean. Initial analysis of water quality data indicates that physical water properties varied by lagoon and season. Seasonal salinity levels appear to be related to a lagoon’s connection with the marine environment; the more directly connected the lagoon is to the Chukchi Sea, the higher its salinity. All lagoons were open to the marine environment during the first round of sampling and closed during the second round of sampling. Salinity levels at Aukulak were higher than the 2017 season, but lower than both the 2016 and 2015 mean salinity levels. Salinity levels at both Krusenstern and Kotlik lagoons were comparable to previous field seasons. Temperature at all three lagoons decreased over the course of the field season. Average temperature at Krusenstern lagoons was 2.5 °C higher that previously recorded. Species richness of fishes and their abundance in lagoons fluctuated during the course of each field season with population composition and relative abundance varying between both season and lagoon. We recorded a total of 22 different fish species, including several key forage and important subsistence species. We found higher overall richness than the 2017 field season wherein 19 species were caught. Species richness was highest at Aukulak Lagoon with 18 different species. We discovered lower overall species diversity in the Tukrok river channel during the 2018 season. Otoliths were extracted from a total of 176 individuals of five species including: humpback whitefish, Being cisco, least cisco, Pacific herring and sheefish. We collected a total of 228 fin clip samples with the majority of samples taken from Krusenstern Lagoon. Muscle plugs were taken at Aukulak Lagoon exclusively, with a total of 30 samples taken from humpback whitefish, least cisco, Pacific herring and sheefish. Our research included collaboration with members of the local community who shared their Traditional Ecological Knowledge with the lagoons field crew and provided insight into their comprehensive understanding of our study sites. Traditional knowledge of local ecosystems is a vital component of this monitoring system that supplements our scientific data collection. Many residents of the areas surrounding Cape Krusenstern, who rely on the lagoons for subsistence purposes, have observed a range of significant changes to these resources, potentially linked to climate change. In our efforts to construct a thorough and comprehensive picture of lagoon ecology and the subsistence resources the lagoons provide, we include these first-hand accounts from local communities. Our primary interaction with Kotzebue residents included a single informal meeting and brief interview with a member of the nearby village. Overall, our research builds on prior traditional knowledge and scientific research, providing ecological information vital for understanding long-term change, monitoring and managing Arctic lagoons of these Park units, helps prioritize spill contingency planning (by establishing the most productive lagoons), and will continue to inform a comprehensive understanding of the Story of the Lagoons – a key priority for the Native Village of Kotzebue, Wildlife Conservation Society, and the National Park Service.

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