length of . After age two, females grow faster than males, with the growth of males tapering off at about age eight, and females continuing to grow until about age 12 to 14. Lingcod live a maximum of about 36 years, reaching a maximum size around . Off the coast of Alaska, many reach . Lingcod are voracious predators, feeding on nearly anything they can fit in their mouths, including invertebrates and many species of fish, such as herring (Clupea pallasii), salmon, and Pacific hake (Merluccius productus). One of their favorite foods is smaller octopuses, and they also readily devour large rockfish. Lingcod that survive the larval stages have few predators themselves, and are vulnerable mainly to marine mammals, such as sea lions and harbor seals. Age determination In 1977, Dr. Dick Beamish and Doris Chilton of the Pacific Biological Station published an article showing that cross sections of the fourth to eighth fin rays from the second dorsal fin provided a method for estimating the age of lingcod.Chilton, D.E. and R.J. Beamish. 1982. Age determination methods for fishes studied by the Groundfish Program at the Pacific Biological Station. Can. Spec. Publ. Fish. Aquat. Sci. 60: 102 p. This method has since been validated by a mark-recapture study in which lingcod received an injection of oxytetracycline. Other methods of aging, such as those using scales and otoliths, were found to underestimate ages for older fish. Ages are determined from fins in much the same manner as for other aging structures: sections of varying thickness are examined under a microscope, and the annuli, or rings, that are formed for each year of growth are counted and used to estimate the age. The cross sections must be made at right angles to the length of the fin ray, and it is therefore important that fins be dried flat, with the cut surface at right angles to the fin rays. In addition, the distance the section is cut from the fin ray base is important, so all fins should be collected with the bases intact.McFarlane, G.A., and J.R. King. The validity of the fin-ray method of age determination for lingcod (Ophiodon elongatus). Fish. Bull. 99: 459-464. One problem associated with using fin rays to age older fish is the center may be resorbed, resulting in the loss of the first two annuli. It is therefore necessary to determine an average width for the