EFFECTS OF MEAL SIZE ON OTOLITH RECOVERY FROM FECAL SAMPLES OF GRAY AND HARBOR SEAL, PUPS

Recovered otoliths from pinniped feces provide valuable information on diet composition and prey site. We studied the effect of meal site on otolith recovery from the feces of one harbor and eight gray seal pup s. Each of 11 experiments comprised a half-ration meal, a period of fe cal collection, a 1.5- or double-ration meal again followed by a perio d of fecal collection. A significantly lower percentage of Atlantic he rring otoliths were recovered from half-ration meals (25% +/- 12.5% in the harbor seal, 8.6% +/- 6.9% in eight gray seals) than from 1.5- or double-ration meals (62.5% +/- 3.1% in the harbor seal, 32.8% +/- 23. 5% in gray seals). Meal size also significantly affected the percentag e of Atlantic cod otoliths recovered from gray seal feces (65.0% +/- 2 6.3% from half ration, 98.3% +/- 2.9% from 1.5 ration). For both size meals, recovered cod otoliths were more significantly eroded than herr ing otoliths. The development of correction factors to account for the effects of digestion will need to consider the distribution of meal s izes of free-ranging pinnipeds.