TAMONE, S.L.**; THOMTON, J.D.; University of Alaska Southeast; University of Alaska Fairbanks, Alaska Sea Life Center: Eyestalk Ablation of Female Dungeness Crabs Cancer magister Yields Diverse Results Dependent upon Physiological State.

The crustacean eyestalk is the source of numerous neurohormones that regulate important physiological processes such as reproduction, growth, metabolism, and coloration. Neurohormones are synthesized in the X-organ and stored in the sinus gland within the eyestalk of crustaceans. Eyestalk ablation (EA) is a technique used to manipulate the physiology of crustaceans by removing the influence of the eyestalk hormones. Induction of vitellogenisis is known to occur upon EA in studied crustaceans since specific regulatory inhibitory hormones are removed. Eyestalk ablation is commonly used to induce molting due to the removal of molt inhibiting hormone, which stimulates the secretion of molting hormones (ecdysteroids) that promote ecdysis. In a group of mature female non-ovigerous Dungeness crab, Cancer magister , EA resulted in either vitellogenesis or ecdysis, but not both. Increases in the yolk protein, vitellogenin (Vg) could be measured after EA in four of the five crabs manipulated. Vitellogenesis was measured using SDS-PAGE followed by silver staining. Levels of Vg increased 6.2 � 1.1 fold. In a single female, ecdysteroids initially measured at 35 ng/ml (intermolt levels) increased one week post ablation (78 ng/ml) and peaked 47 days prior to ecdysis (2590 ng/ml). The length of premolt period was 167 days and the change in ecdysteroids was not significantly different from those measured in control animals undergoing ecdysis in the laboratory. Non-ovigerous control females did not undergo vitellogenesis during the duration of the experiment. Current studies are investigating whether EA of post molt mature females or ovigerous females will induce ecdysteroid synthesis or Vg synthesis.