DDT residues were average or less than average in lobsters, five species of molluscan shellfishes, and seven species of finny fishes from estuarial and coastal waters of New Brunswick and Prince Edward Island, compared with the same or similar species elsewhere in North America and northern Europe. Mackerel had the highest residues, averaging 0.38 ppm of DDT or 0.54 ppm of DDT plus metabolites. These levels do not seem to be an immediate danger to the fish. In terms of human diet, residues in mackerel are as high as those in some beef. The other species averaged 0.1 ppm or less of total DDT residue in the whole body or muscle, usually much less. This is relatively low by present day findings. Viscera of salmon, cod, and hake had 6–15 times higher concentrations of DDT residues than did muscle. Flounder viscera had no more residue than did muscle, whereas lobster eggs had nine times as much as muscle. None of the four sampling locations produced consistently higher residues than the others.