Dear MARMAM: The Following paper has been published online in Marine Biodiversity Records Juan-Pablo Gallo-Reynoso, Janitzio Égido-Villarreal and Elsa-María Coria-Galindo. 2009. Sperm whale distribution and diving behaviour in relation to presence of jumbo squid in Guaymas Basin, Mexico. Marine Biodiversity Records. doi:10.1017/S1755267209990571 Abstract Sperm whale Physeter macrocephalus distribution was compared to acoustic backscatter observations in the Gulf of California. Forty-three sperm whale groups totalling 813 individuals were encountered during 28 observation days Sperm whales occurred over deep waters (mean depth = 659 mrange: 300–1800 m). A significant correlation was found between the whales' maximum depth of dive and depth of the acoustic scattering layer (N = 36r2 = 0.944P = 0.000). We observed sperm whales dive to the scattering layer and then surface with prey in their jaws: jumbo squid Dosidicus gigas (10 events) and unidentified fish (one event). The average depth of sperm whale foraging dives to the scattering layer was 342 m the average diving time was 23 minutesand the average surface interval between foraging dives was 6 minutes. Sperm whales spent 75% of their time diving and 25% on the surface. Swimming speed at the surface was slower when whales reached scattering layers during a dive (2.4 km/h) compared to dives when no scattering layer was reached (8.9 km/h). Our results establish a direct link between sperm whale distribution and presence of its prey in the Gulf of California. For more information contact Dr. Juan Pablo Gallo: jpgallo@ciad.mx Kind regards, Janitzio MDI Janitzio Égido Villarreal Investigador Asociado Laboratorio de Ecofisiología CIAD - Unidad Guaymas Carretera al Varadero Nacional Km 6.6 Col. Las Playitas Guaymas, Sonora 85480 MEXICO Tel.: 01(622) 22 1 65 33 Ext. 117