This file contains data on numerical abundance of mesopelagic fishes collected in winter (December 2009) and summer (July 2010) in the Balearic Islands region. A relatively small area was repeatedly sampled throughout the day. Samples were obtained by means of a double-warp modified commercial mid-water trawl, with standard pelagic trawl doors (otter boards) and graded-mesh netting to the cod-end (10 mm). Hauls were horizontal and lasted between 30 min and 1 hour, and the depth of the net was controlled by a SCANMAR system. Samples were identified on board or frozen for a later identification in the laboratory. These data were obtained within the project: "Estructura y dinámica del ecosistema bentopelágico de talud en dos zonas oligotróficas del Mediterráneo: una aproximación multidisciplinar y a distintas escalas temporales en las Islas Baleares", financed by the Spanish Ministerio de Ciencia e Innovación CTM2007-65844-C03.

Haul layer code: Net acronym, haul number, layer acronym (DSL: Deep Scattering Layer, Surf: Surface, BBL: Benthic Boundary Layer)