Gulf Watch Alaska Nearshore Component: Intertidal Mussel Site Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park, 2016

This data is part of the Gulf Watch Alaska (GWA) long term monitoring program, nearshore monitoring component. Specifically, these data describe mussel sampling and observations conducted in the northern Gulf of Alaska within the GWA program. The dataset consists of five comma separated files exported from a Microsoft excel workbook. The data consists of 1. Mussel sampling site layout information, 2. Mussel count and 3. Size measurements for mussels greater than 20 millimeters, 4. Mussel count and 5. Size measurements for all mussels collected from core samples. Samplers used transect tapes, quadrat frames, rulers, and core tools to sample mussels from mussel sites. Mussels greater than 20 millimeters were collected from a quadrat and measured with dial calipers to the nearest millimeter. Associated with the quadrat, but not within it, a small core sample was collected and all mussels greater than 1mm were counted and measured (measurements began in 2014). Sampling year, region, block, site, quadrat number, quadrat size (overall area sampled), and number of mussels in the core were recorded. Sites are in Alaska and include locations in Katmai National Park and Preserve, Kenai Fjords National Park and Prince William Sound. There are five mussel sites in each of those three regions. The time interval includes 2016.
Pacific blue mussels (Mytilus trossulus) are a conspicuous and abundant filter feeding marine invertebrate in the intertidal zone. Mussels are widely distributed, but also form relatively monotypic stands of larger individuals that are termed mussel beds. Although a number of factors such as environment, disturbance, predation and competition influence the abundance and distribution of mussels, they can be a competitively dominant intertidal species. Within the nearshore foodweb, mussels area a source of energy to a wide array of invertebrate, avian, and mammalian predators and are critically important prey for sea otters, black oystercatchers, harlequin ducks, Barrows goldeneye, and several species of sea stars.
The purpose of this task is to assess change in the density and size distribution of mussels (Mytilus trossulus) in mussel beds. These data are primarily to be used as an indicator of mussel prey for various predators, including sea otters, black oystercatchers, sea ducks and sea stars. Specifically, the objectives of this task are to assess changes in: 1) The size (area) of selected mussel beds, 2) The density of mussels within these beds, and 3) The size distribution of mussels within the beds. Sampling will be conducted in sheltered rocky habitats within each of the regions (Kenai Peninsula (KEP), Alaska Peninsula (AKP), and Prince William Sound (PWS).