Clams were once a major subsistence resource of the native communities of Nanwalek and Port Graham in lower Cook Inlet and Tatitlek in Prince William Sound. Local clam populations have been decreasing for the past 30 years, and their contribution to the subsistence harvest has been greatly reduced. Several factors likely contribute to this decline, including the 1964 earthquake altering beach elevations and habitats, the Exxon Valdez oil spill, changes in currents and beach patterns, and increasingly heavy sea otter predation.
Given these ongoing challenges, it became crucial to assess the current state of clam populations and their habitats. To that end, beach surveys were conducted on August 28, August 31, and September 1, 2024 at three key sites in the Chugach Region. These sites were selected for their historical significance as traditional shellfish harvest areas and had been previously surveyed in 1995 under Exxon Valdez Oil Spill Project 95131. The primary objective of the recent surveys was to evaluate the present condition of native hardshell clam populations, utilizing current technologies and compare them to data collected in 1995.
Researchers used systematic random quadrat sampling to quantify the abundance and diversity of bivalve species at each site. Sediment samples were collected to evaluate habitat suitability, and GPS coordinates were recorded for all quadrat and sediment sampling locations to support accurate georeferencing and spatial analysis. These data informed the development of population density and habitat suitability maps using GIS tools. The results confirmed local knowledge that populations continue to decline and that shellfish enhancement tools should be employed to help reestablish local populatins.