Copeia, 2003(2), pp. 392-397 ANTIPREDATOR DEFENSES OF LARVAL PACIFIC GIANT SALAMANDERS (DICAMPTODON TENEBROSUS) AGAINST CUTTHROAT TROUT (ONCORHYNCHUS CLARKI)

—We tested larval Pacific giant salamanders (Dicamptodon tenebrosus) for chemical and behavioral defenses against cutthroat trout (Oncorhynchus clarki). Youngof-year Dicamptodon were fully palatable to trout during single and repeated offerings. However, larvae increased refuge use in response to chemical cues from trout, although they did not select different microhabitats (shallow or deep) between trout treatments and controls. Our results suggest that while Dicamptodon larvae are potentially vulnerable to predation by cutthroat trout, increased refuge use by larvae in response to trout chemical cues may reduce the probability of encounters and contribute to the coexistence of these species.