GMU 416 - Decatur, Washington

Low-elevation marine island in the Salish Sea between Lopez Sound and Rosario Strait, San Juan County, Washington. Decatur Island lies mostly at or just above sea level with gently rolling topography typical of the San Juan archipelago. Vegetation is dominated by second-growth Douglas-fir and madrone forest interspersed with open meadows and brushy edges. The island is small (roughly 6 square miles) with a rocky shoreline, no significant elevation relief, and a mild, wet maritime climate with high annual precipitation. No river corridors, mountain foothills, or Cascades terrain; entirely island/marine character.

Access requires private boat or commercial water taxi — Decatur Island is not served by the Washington State Department of Transportation (WSDOT) ferry system. Most private docks and landings are privately owned; hunters should confirm mooring rights in advance. San Juan County owns and maintains several docks and boat ramps in the archipelago. Almost all land on Decatur Island is privately held; WDFW, BLM, and DNR have no significant ownership on Decatur specifically (unlike Cypress, Lopez, or Orcas islands where some public parcels exist). San Juan County ordinance requires written landowner permission before hunting any private property. No WDFW Private Lands Access Program (PLAP) properties had been enrolled on Decatur Island as of the 2025 season, though WDFW continues to negotiate island access. The WDFW Hunt by Reservation system is available for any properties that become enrolled. Overnight camping is not available on Decatur Island through public land managers.

Pacific maritime forest dominated by Douglas-fir, western red cedar, and Pacific madrone. Understory includes salal, Oregon grape, sword fern, and ocean spray. Openings and forest edges provide browse for deer. No alpine or subalpine zones. The island's mild climate and browsable shrub layer support year-round deer foraging. Deer tend to be smaller-bodied than mainland black-tails, consistent with island resource limitations.

Resident island population with no seasonal migration. Deer are year-round island residents with no connection to mainland herds. Population dynamics driven by island carrying capacity, forage availability, and disease cycles. The 2021 Adenovirus Hemorrhagic Disease (AHD) outbreak impacted multiple nearby San Juan Islands (Blakely, Henry, Lopez, Shaw, Stuart) though Decatur was not specifically listed as an AHD-confirmed unit; AHD was also detected on BC Gulf Islands in fall 2024. Deer have historically been overabundant on San Juan Islands as a district management concern. No elk movement — no elk herd exists in the San Juan Islands. No black bear documented on Decatur Island.

Firearm restrictions are in effect throughout San Juan County — all big game hunting on Decatur Island is subject to those restrictions, effectively limiting practical methods; archery is the predominant approach. Legal deer designation is 'any deer' (no antler restriction) for all seasons. Hunters must report the correct GMU (416) on harvest reports — WDFW notes ongoing misreporting among island GMUs that impairs population assessment. Resident islanders often value deer and may be reluctant to grant permission; access should be secured well in advance. No special permits or limited-entry draws are required for GMU 416; it is an over-the-counter tag unit. The San Juan County Land Bank and WDFW PLAP may expand access opportunities — check wdfw.wa.gov for current enrolled properties before each season. Harvest data for GMU 416 specifically is limited due to historical misreporting; WDFW is working to improve accuracy.