Influence of Environmental Conditions on Mytilus trossulus Size Frequency Distributions in Two Glacially Influenced Estuaries

Abstract The Pacific blue mussel ( Mytilus trossulus ) is a foundation species in high-latitude intertidal and estuarine systems that creates complex habitats, provides sediment stability, food for top predators, links the water column benthos. M. also makes an ideal model to assess biological responses environmental variability; specifically, its size frequency distributions can be influenced by environment which it lives. Mussels inhabit estuaries high latitudes receive freshwater runoff from snow glacial-fed rivers or under oceanic influence. These hydrographic conditions work together with local static characteristics, such as substrate type, fetch, beach slope, distance freshwater, glacial discharge influence demographics. In 2019 2020, mussels were collected two Gulf of Alaska ecoregions determine whether frequencies change over spatial (local ecoregional) scales any characteristics correlate this variability. This study demonstrated most comparable at sites similar conditions, according ecoregion year they collected. Hydrographic explained approximately 43% variation both years, combined ecoregions. Mussel recruits (0–2 mm) more abundant higher while large (> 20 protected sites. Fetch years across ecoregions, slope important 2020. suggests may play role structuring sizes. Although differences found depending on sizes showed little difference differing types influence, so resilient changes associated melting glaciers.