21. Determination of Gastric Evacuation Rate for Immature Spiny Dogfish
Abstract.—Gastric evacuation rate was estimated for immature spiny dogfish Squalus acanthias from the San Juan Islands, Washington. Dogfish were fed known quantities of herring and removed at intervals after feeding to recover the remaining portion of the meal. Stomach contents were recovered using the non-lethal technique, gastric lavage. Regression analysis was used to evaluate the adequacy of linear, square root, and exponential models in describing the decrease in stomach contents over time. An exponential model proved best at describing the pattern of evacuation. Gastric evacuation in immature dogfish was comparable to that of other elasmobranchs of similar size at similar temperatures. Re-using test subjects did not significantly impact gastric evacuation estimates.