Does trawl fisheries affect the diet of fishes? A stable isotope analysis approach

Trawling is the main fishing practice worldwide and its ecosystem effects have been raising concern over the past decades. Long-term impacts can be monitored through changes in the trophic structure, and several studies evaluated trophic level (TL) shifts in fish populations between trawled and untr...

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Bibliographic Details
Published in:Isotopes in environmental and health studies 2019-07, Vol.55 (4), p.327-343
Main Authors: Funes, Manuela, Marinao, Cristian, Galván, David E.
Format: Article
Language:English
Subjects:
Bycatch consumption
carbon-13
Diet
Ecological monitoring
Ecosystem assessment
Ecosystems
Environmental changes
Fish populations
Fisheries
fisheries impact
Fishing
Hake
isotope ecology
metanalysis
Niches
nitrogen-15
Northern Hemisphere
Patagonia
reef fish
Southern Hemisphere
Stable isotopes
Studies
Trawling
Trophic levels
trophic position
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Summary:Trawling is the main fishing practice worldwide and its ecosystem effects have been raising concern over the past decades. Long-term impacts can be monitored through changes in the trophic structure, and several studies evaluated trophic level (TL) shifts in fish populations between trawled and untrawled environments. However, published results are contrasting. We performed a metanalysis integrating all available studies that evaluated TL shifts in fishes between trawled and untrawled environments and conducted a local study comparing several features of the trophic ecology in two species of fishes. According to the metanalysis, TL does not change significantly with trawling. In contrast, the local study showed higher TLs and broader isotopic niches in the trawled environment. Diet reconstruction indicated a potential consumption of hake, the main discard component, at the trawled environment. All the studies used in the metanalysis were conducted in the Northern Hemisphere, whereas the local study represents the first data available from the Southern Hemisphere. As industrial commercial fisheries in Argentina are relatively recent, it is possible that our data are capturing the initial stage of ecological changes induced by trawling, compared with the historical fisheries located at the Northern Hemisphere.
ISSN:1025-6016
1477-2639
DOI:10.1080/10256016.2019.1626381