Fish early life stages associated with giant kelp forests in sub-Antarctic coastal waters (Beagle Channel, Argentina)

Abstract

The aim of this study was to assess seasonal and spatial variations in fish larvae abundance between areas with Macrocystis pyrifera kelp forests and areas without them off the coast of the Beagle Channel. Monthly plankton sampling at three sites was performed from June 2014 to May 2016 in two areas of each site. One area was defined along the offshore margin (edge of the forests) of M. pyrifera kelp forests and the other area parallel to the forests but 200 m offshore (out of the forests). To test for spatial and temporal differences in the abundance of fish larvae, a multiple-hypothesis model approach was adopted by fitting generalized models (GLMs) with the abundance of fishes as the response variable and possible combinations of seasons, sites, areas, and water parameters as explanatory variables. Ten fish taxa in larval stage were collected of which Patagonotothen spp. larvae were the dominant group. Season and area affected most the abundance of fish larvae along the coast of the Beagle Channel. High abundance of fish larvae was collected in spring of both years with a second peak in autumn. Harpagifer bispinis and Patagonotothen spp. peaked in spring, while Careproctus pallidus peaked in autumn. In every season of the two years sampled, the abundance of fish larvae was higher at the edge of the forests than out of them. The importance as nursery ground of M. pyrifera kelp forests for early stages of fishes that inhabit the Beagle Channel is discussed.