Because of such human activities as overfishing, development, dam building, logging, and farm irrigation, Pacific salmon populations have greatly declined, and many species are now listed as rare and endangered. The United States and Canada negotiated a conservation agreement in 1999 that includes setting catch limits based upon ongoing scientific assessments of salmon population levels. In addition, multiple-approach conservation efforts are under way in Washington and Oregon states to restore the salmon runs. For reasons less well understood, and despite international conservation measures, Atlantic salmon populations have also sharply declined. The desirability of salmon as food fish has led to their being raised in aquaculture.