For many mesopelagic fishes, even basic knowledge regarding their biology is missing, greatly impeding effective management. Here we present length–weight relations for 16 fishes sampled during research surveys in the Greek seas (eastern Mediterranean). The following species were studied: Benthosema glaciale (Reinhardt, 1837); Ceratoscopelus maderensis (Lowe, 1839); Diaphus holti Tåning, 1918; ...