Project

Of sharks, salmon and sea-farms

Species
  • Sharks
Years funded
  • 2021
Status
  • Active
Project type
  • Research
Affiliation
  • Universidad Austral de Chile
Description

Joaquín’s love of time at sea, and enthusiasm for working with fishers, comes in handy for his project. He collaborates with local fishers to collect shark stomach and muscle samples in southern Chile’s marine waters. By processing these samples, he hopes to understand what the sharks are eating – and understand what impact salmon aquaculture is having on where sharks are moving, and what they’re eating, in Patagonia’s fjords.

Of sharks, salmon and sea-farms

Joaquín Soto

Project leader
About the project leader

The place where I can recharge my batteries and reset my mind has always been the ocean. I grew up in Puerto Montt in southern Chile, spending the summers at the beach and on rocky shores where the marine biodiversity is spectacular. Currently, as a marine biology student, I usually spend my weekends diving, fishing and connecting with the ocean’s energy. My bond with marine animals started with my family’s passion for preparing seafood meals. I began to ask myself where these animals we were cooking came from and soon I was looking in the wild for all the species...

PROJECT LOCATION : Chile, Patagonia’s fjords
Project details

Effects of salmon aquaculture on diet and habitat use of Chondrichthyes from unique Patagonian fjords

Key objective

The project aims to assess the effects of salmon aquaculture on the diet and habitat use of three Patagonian Chondrichthyes based on stomach content and stable isotope analyses.

Why is this important

Chile is the second-largest salmon producer in the world. Salmon aquaculture concentrates in Patagonian fjords in the South of the country and has exponentially increased in recent decades. Still the effects of the aquaculture on Chondrichthyes that inhabit fjords are unknown. Thus, the present study aims to evaluate the effect of salmon aquaculture on the diet and habitat use of three Patagonian Chondrichthyes to inform aquaculture planning and prioritize conservation areas.

Background

Chilean Patagonian fjords are among few remaining largely undisturbed ecosystems and are a global conservation priority. Still, salmonid aquaculture ranks among the most important economic activities in Patagonian fjords (southern Chile) and the number of salmon farms is expected to double in the coming decade. This aquaculture expansion may cause significant environmental impacts such as severe alteration of benthic communities in farm proximities. As such impacts on local benthic Chondrichthyes such as Narrowmouth catshark (Schroederichthys bivius) categorized as ‘data deficient’ by the International Union for Conservation of Nature IUCN and American elephantfish (Callorhinchus callorhynchus) (‘vulnerable’ according to the IUCN) that feed principally on benthic prey may also be expected. In contrast, Spiny dogfish (Squalus acanthias) (‘vulnerable’ according to the IUCN) only occasionally feeds on benthic prey so it should be less affected by benthic community changes. However, the diet of Spiny dogfish may also be directly affected by aquaculture activity as it was shown to consume pellets in the proximity of net pens. This project aims at a comprehensive assessment of the effects of salmon farm presence on the diet of Chondrichthyes in the Patagonian fjord ecosystem by a combination of stomach content and stable isotope analyses. Stomach content analyses allow assessment of diet on a short temporal scale of days and provide proportional data. Analyses of stable isotopes of carbon, nitrogen and sulphur allow assessment of diet integrated on a longer temporal scale of months and provide continuous numeric data that reflect ecological and biological processes that result in organism´s isotopic signature.

Aims & objectives
  • Assess the effects of salmon aquaculture on stomach content (diet on a short temporal scale) of three Patagonian Chondrichthyes.
  • Assess the effects of salmon aquaculture on diet integrated over a longer period of time and habitat use of three Patagonian Chondrichthyes species based on stable isotope analyses.