Impacts of Ferry Terminals on Juvenile Salmon Migrating along Puget Sound211 Shorelines. Phase 1. Synthesis of State of Knowledge

摘要

The project is assessing whether ferry terminals affect juvenile salmon migrating211u001ealong estuarine and nearshorre marine environments and, if so, how design of and 211u001emodifications to both ferry terminals and operations can mitigate those impacts. 211u001eThis project has three phases. This report summarizes results from Phase I 211u001e(status of knowledge, initial terminal surveys) and implications for Phase II and 211u001eIII research. We addressed three issues about over-water structures impacts on 211u001ejuvenile salmon: (1) alteration in migratory behavior, (2) reduction in prey 211u001eproduction and availability, and (3) increased predation. An assessment of over 211u001e60 direct sources of information found evidence that juvenile salmon react to 211u001eshadows and other artifacts in the shoreline environment created by shoreline 211u001estructures. While changes in light have been shown to affect salmon migration 211u001ebehavior and thus potentially place them at increased mortality risk, we found no 211u001equantitative information on the significance of these behavioral responses to 211u001ejuvenile salmon survival. Juvenile salmon also encounter limited prey resources 211u001eunder shoreline structures when important habitats such as eelgrass (Zostera 211u001emarina) are disturbed.