Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas
Tunas are among the most exploited top predators worldwide, with negative impacts on some of their stocks. Changes in their population abundance can impact marine food-webs and have the potential to alter entire ecosystems. To better understand the impacts of the exploitation of tuna stocks in the m...
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ftispalisboa:oai:repositorio.ispa.pt:10400.12/8044 2023-05-15T17:41:43+02:00 Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas Romero, Joana Catry, Paulo Hermida, Margarida Neves, V C Cavaleiro, Bárbara Gouveia, Lídia Granadeiro, José Pedro 2021-03-20T01:05:40Z http://hdl.handle.net/10400.12/8044 https://doi.org/10.1016/j.fishres.2021.105914 eng eng elsevier PTDC/MAR-PRO/ 0929/2014 Fisheries Research, 238, 1-9 Doi:10.1016/j.fishres.2021.105914 01657836 http://hdl.handle.net/10400.12/8044 doi:10.1016/j.fishres.2021.105914 openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Thunnus obesus Katsuwonus pelamis Diet Mercury Northeast Atlantic Ocean article 2021 ftispalisboa https://doi.org/10.1016/j.fishres.2021.105914 2022-05-30T08:47:22Z Tunas are among the most exploited top predators worldwide, with negative impacts on some of their stocks. Changes in their population abundance can impact marine food-webs and have the potential to alter entire ecosystems. To better understand the impacts of the exploitation of tuna stocks in the most critical habitats, basic knowledge on the diet of these species in each region is required. Here, we describe the diet of the two most fished tuna species in the archipelago of Madeira, the Bigeye tuna Thunnus obesus and the Skipjack tuna Katsuwonus pelamis, based on stomach contents analysis. To gain further insights into the diet, and also better assess the possible bias caused by the occurrence of live bait in stomachs, we compared tuna mercury values with those of two other predators with similar diets that are not directly targeted by fisheries, and with Bigeye and Skipjack tunas from other ocean basins. Bigeye tunas fed mostly on Atlantic chub mackerel Scomber colias and mackerel Trachurus sp., which together contributed with 85% of total prey weight. Only 7.5% of prey weight was constituted by mesopelagic prey, including myctophids and cephalopods. Skipjack tunas had an epipelagic diet (NF = 97%), with the Atlantic chub mackerel representing half of the total prey weight, despite Longspine snipefish Macroramphosus scolopax and Sand smelt Atherina sp. accounting for 62.9% of the total number of prey. There were interannual variations in diet likely linked to interannual pelagic community shifts. Bait did not bias the results of the stomach analysis of these tunas and bait species were observed to be part of the natural diet of both tuna species. Baseline data provided by this study should allow for more informed decisions for an efficient ecosystem-based fisheries management. Fundação para a Ciência e Tecnologia - FCT info:eu-repo/semantics/publishedVersion Article in Journal/Newspaper Northeast Atlantic Instituto Universitário de Ciências Psicológicas, Sociais e da Vida: Repositório do ISPA Fisheries Research 238 105914 |
institution |
Open Polar |
collection |
Instituto Universitário de Ciências Psicológicas, Sociais e da Vida: Repositório do ISPA |
op_collection_id |
ftispalisboa |
language |
English |
topic |
Thunnus obesus Katsuwonus pelamis Diet Mercury Northeast Atlantic Ocean |
spellingShingle |
Thunnus obesus Katsuwonus pelamis Diet Mercury Northeast Atlantic Ocean Romero, Joana Catry, Paulo Hermida, Margarida Neves, V C Cavaleiro, Bárbara Gouveia, Lídia Granadeiro, José Pedro Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
topic_facet |
Thunnus obesus Katsuwonus pelamis Diet Mercury Northeast Atlantic Ocean |
description |
Tunas are among the most exploited top predators worldwide, with negative impacts on some of their stocks. Changes in their population abundance can impact marine food-webs and have the potential to alter entire ecosystems. To better understand the impacts of the exploitation of tuna stocks in the most critical habitats, basic knowledge on the diet of these species in each region is required. Here, we describe the diet of the two most fished tuna species in the archipelago of Madeira, the Bigeye tuna Thunnus obesus and the Skipjack tuna Katsuwonus pelamis, based on stomach contents analysis. To gain further insights into the diet, and also better assess the possible bias caused by the occurrence of live bait in stomachs, we compared tuna mercury values with those of two other predators with similar diets that are not directly targeted by fisheries, and with Bigeye and Skipjack tunas from other ocean basins. Bigeye tunas fed mostly on Atlantic chub mackerel Scomber colias and mackerel Trachurus sp., which together contributed with 85% of total prey weight. Only 7.5% of prey weight was constituted by mesopelagic prey, including myctophids and cephalopods. Skipjack tunas had an epipelagic diet (NF = 97%), with the Atlantic chub mackerel representing half of the total prey weight, despite Longspine snipefish Macroramphosus scolopax and Sand smelt Atherina sp. accounting for 62.9% of the total number of prey. There were interannual variations in diet likely linked to interannual pelagic community shifts. Bait did not bias the results of the stomach analysis of these tunas and bait species were observed to be part of the natural diet of both tuna species. Baseline data provided by this study should allow for more informed decisions for an efficient ecosystem-based fisheries management. Fundação para a Ciência e Tecnologia - FCT info:eu-repo/semantics/publishedVersion |
format |
Article in Journal/Newspaper |
author |
Romero, Joana Catry, Paulo Hermida, Margarida Neves, V C Cavaleiro, Bárbara Gouveia, Lídia Granadeiro, José Pedro |
author_facet |
Romero, Joana Catry, Paulo Hermida, Margarida Neves, V C Cavaleiro, Bárbara Gouveia, Lídia Granadeiro, José Pedro |
author_sort |
Romero, Joana |
title |
Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
title_short |
Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
title_full |
Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
title_fullStr |
Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
title_full_unstemmed |
Tunas off northwest Africa: The epipelagic diet of The Bigeye and Skipjack tunas |
title_sort |
tunas off northwest africa: the epipelagic diet of the bigeye and skipjack tunas |
publisher |
elsevier |
publishDate |
2021 |
url |
http://hdl.handle.net/10400.12/8044 https://doi.org/10.1016/j.fishres.2021.105914 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_relation |
PTDC/MAR-PRO/ 0929/2014 Fisheries Research, 238, 1-9 Doi:10.1016/j.fishres.2021.105914 01657836 http://hdl.handle.net/10400.12/8044 doi:10.1016/j.fishres.2021.105914 |
op_rights |
openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1016/j.fishres.2021.105914 |
container_title |
Fisheries Research |
container_volume |
238 |
container_start_page |
105914 |
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1766143414210920448 |