Vieira, Rui. 2011. Estrutura populacional de Electrona antarctica (Gunther, 1878) e Gymnoscopelus braueri (Lonnberg, 1905) no Mar de Scotia (Oceano Antártico).

Myctophidae fish species are the main alternative to the krill Euphausia superba, the basis of typical Antarctic foodweb. In the Southern Ocean, the estimated biomass of myctophids ranges between 70 and 200 million tons. Due to carrying out daily vertical migrations between the surface and 1000 m deep, myctophids provide energy to top predators in the surface layers, such as Dissostichus eleginoides (Patagonian toothfish), Diomedea exulans (Wandering Albatross) and Aptenodytes patagonicus (King penguin). Electrona antarctica and Gymnoscopelus braueri are two mesopelagic species of the family Myctophidae, whose knowledge in terms of biology and ecology is scarce. The population structure, age and growth of these two lanternfish species were investigated. Samples were collected during cruises conducted by the British Antarctic Survey in the Scotia Sea between 2004 and 2009. A sample of 405 individuals�f E. antarctica, with standard length between 30 mm and 112 mm was used to assess age, through otolith analysis, and estimate the Von Bertalanffy growth curve parameters. The estimated ages ranged from 2 to 8 years. The estimated parameters were L�‡ = 139 mm, k = 0.16 year-1 and t0 = -0.27 years. A G. braueri sample of 161 individuals, with standard length ranging from 44 mm and 139 mm, was used to estimate growth parameters. The estimated parameters were L�‡ = 128 mm, k = 0.33 year-1, t0 = -0.36 year and the maximum age observed was 6 years for this species.