Long-duration (>1 s) marine mammal vocalizations (i.e., blue whale calls) generate echos and other multipath effects [McDonald et al., J. Acoust. Soc. Am. 98, 712--721 (1995)], obscuring the original structure of the call, which may contain valuable anatomical information about the animal. Several deconvolution techniques are evaluated for their effectiveness in removing multipath effects from both a hypothetical and actual marine mammal call. The evaluation is first performed on a model of a whale call in an isovelocity waveguide with noise, where the source signal is known and can be compared with the output of the deconvolution schemes. The methods are then applied to two blue whale calls recorded during an experiment (SWellEx-3) in July, 1994 in 200-m water. The depth and range of the animal at those two times had previously been determined by matched field processing. As the position of the animal is known, the resulting multipath propagation can be computed and the accuracy of the techniques in identifying those multipaths determined.