This data report presents the results of the field collections and chemical analyses of fish and crab tissue conducted as part of the Phase 2 Remedial Investigation (RI) for the Lower Duwamish Waterway (LDW). Six fish species and two crab species were collected from the LDW and analyzed for tissue chemistry. Other species of fish and invertebrates caught while collecting the target species were recorded for the RI biological community discussions. A subset of LDW target species was also collected from two background locations, along with sediment,1 and analyzed for total and inorganic arsenic for comparison with total and inorganic arsenic concentrations in fish and crab tissue samples collected from the LDW. The fish and crab tissue Quality Assurance Project Plan (QAPP; Windward 2004b) presented the design for this study, including details on project organization, field data collection, laboratory analyses, and data management. As described in the Phase 2 RI work plan (Windward 2004c), these fish and crab tissue data will be used to support the Phase 2 ecological risk assessment and human health risk assessment in the RI, and may be used to calculate sediment risk-based goals, based on sediment-tobiota relationships. The remainder of this report is organized into the following sections: Section 2 - Field collection and sample processing methods; Section 3 - Analytical methods; Section 4 - Chemical analysis results; and Section 5 - References. The text is supported by the following appendices: Appendix A - Data tables; Appendix B - Compositing information; Appendix C - Data management; Appendix D - Data validation reports; Appendix E - Laboratory-reported results; Appendix F - Field forms, notes, and navigation report; and Appendix G - Chain-of-custody forms.