Marine effect of introduced salmonids: Prey consumption by exotic anadromous rainbow and brown trout in the Patagonian Continental Shelf

CIANCIO, J.E.; BEAUCHAMP, D.; PASCUAL, M.A.

LIMNOLOGY AND OCEANOGRAPHY

AMER SOC LIMNOLOGY OCEANOGRAPHY

Año: 2010

0024-3590

<!-- /* Font Definitions */ @font-face {font-family:Garamond; panose-1:2 2 4 4 3 3 1 1 8 3; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:647 0 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin-top:6.0pt; margin-right:0cm; margin-bottom:0cm; margin-left:0cm; margin-bottom:.0001pt; text-align:justify; mso-pagination:widow-orphan; text-autospace:none; font-size:12.0pt; font-family:Garamond; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:Garamond; color:black; mso-ansi-language:EN-US;} p.entry, li.entry, div.entry {mso-style-name:entry; margin-top:0cm; margin-right:0cm; margin-bottom:6.0pt; margin-left:27.2pt; text-align:justify; text-indent:-27.2pt; mso-pagination:widow-orphan lines-together; text-autospace:none; font-size:12.0pt; font-family:Garamond; mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:Garamond; color:black; mso-ansi-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> 13 For centuries humans have been spreading salmonids in rivers around the world, a process that14 has increased exponentially during the past two centuries. The freshwater impacts of salmonids15 have been studied in several places around the world, but no information is available on marine16 environments. In Southern Patagonia, Pacific and Atlantic rivers have self-sustained17 populations of exotic anadromous salmonids. Based on stable isotopes analysis we estimated18 the diet of the most abundant anadromous salmonid species on Patagonian Atlantic basins. The19 results were coupled with bioenergetic and population models to estimate the consumption of20 food of and compared with food consumption by sea birds, the most abundant top predators in21 the area. Amphipods were the main prey, followed by sprat, then silversides, squid, and22 euphausiids. The overall consumption by salmonids was minor as compared to native top23 predators. The total consumption assuming large size salmonids populations consisted on less24 than 5% of total bird consumption. Meanwhile, we identified particular seabird colonies and25 artisanal fisheries with which trophic interactions could be significant.