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Abstract

Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River †

by
Ana Filipa Belo
1,*,‡,
Catarina Sofia Mateus
1,
Bernardo Ruivo Quintella
2,3,
Esmeralda Pereira
1,
André Moreira
1,
Roberto Oliveira
1,
Carlos Batista
4 and
Pedro Raposo de Almeida
1,5
1
MARE—Centro de Ciências do Mar e do Ambiente/ARNET—Aquatic Research NETwork, Universidade de Évora, 7002-554 Évora, Portugal
2
MARE—Centro de Ciências do Mar e do Ambiente/ARNET—Aquatic Research NETwork, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
3
Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
4
Departamento de Recursos Hídricos e Departamento do Litoral e Proteção Costeira, Agência Portuguesa do Ambiente, I.P., 2610-124 Amadora, Portugal
5
Departamento de Biologia, Escola de Ciências e Tecnologias, Universidade de Évora, 7002-554 Évora, Portugal
*
Author to whom correspondence should be addressed.
Presented at the IX Iberian Congress of Ichthyology, Porto, Portugal, 20–23 June 2022.
Presenting author (Oral communication).
Biol. Life Sci. Forum 2022, 13(1), 126; https://doi.org/10.3390/blsf2022013126
Published: 17 June 2022
(This article belongs to the Proceedings of The IX Iberian Congress of Ichthyology)

Abstract

:
Allis shad (Alosa alosa L.) populations have suffered declines and even regional extinction across their distribution range, mainly due to river impoundment, overexploitation, and pollution. In Portugal, the species is classified as Endangered (EN). This fish is regarded as a valuable delicacy, and commercial fisheries dedicated to this species in Portugal are found in rivers in Minho, Lima, Cávado, Douro, Vouga, Mondego, Tagus, and Guadiana. Official landings state that, in the last 10 years, around 10 t of allis shad were sold annually at the Figueira da Foz fish market. Fisheries are selective since the allowed mesh size for the nets employed does not capture smaller fish. Moreover, larger fish are more desirable, attaining higher prices per kg at fish auctions and thus generating higher revenue for the fishermen. The fishing pressure on this threatened resource in the Mondego is significant and bound to impact its population structure. With the present work, we assess the impact of fishing pressure and gear selectivity on the dimensional structure of the Mondego’s shad spawning population, one of the last strongholds for allis shads, and identify possible consequences for the future of the species. The dimensional structure and gender proportion of over 800 shads sampled at Figueira da Foz fish auction from 2015 to 2019 was analyzed. All shads sampled were between 400 mm and 745 mm in total length, with an average of 592 mm. Simultaneously, we used images recorded in the monitoring window at Açude-Ponte Dam’s fishway in Coimbra to study the shads reaching the upstream spawning areas in order to check for differences in the dimensional structure possibly related to fishing pressure. The results obtained aim to increase the existing biological knowledge of this population and the human pressure it is subjected to, thus contributing to future management efforts.

Author Contributions

Conceptualization, A.F.B., B.R.Q., P.R.d.A.; methodology, A.F.B., B.R.Q., P.R.d.A.; formal analysis, A.F.B., B.R.Q., P.R.d.A.; investigation, A.F.B., C.S.M., E.P., R.O., A.M., B.R.Q., P.R.d.A.; resources, C.B., P.R.d.A.; data curation, A.F.B., C.S.M., C.B.; writing–original drafts presentation, A.F.B.; writing–review and editing, A.F.B., C.S.M., E.P., R.O., A.M., B.R.Q., C.B., P.R.d.A.; supervision, B.R.Q., P.R.d.A.; project administration, C.B., P.R.d.A.; funding acquisition, B.R.Q., P.R.d.A. All authors have read and agreed to the published version of the manuscript.

Funding

The present study was supported by the project ANADROMOS–Plano Operacional de Monitorização e Gestão de Peixes Anádromos em Portugal (MAR-01.03.02-FEAMP-0002) funded by the European Fisheries Fund, and by the Portuguese Environment Agency (APA) through the “Coimbra fish pass monitoring program”. In addition, this study had the support of FCT through the strategic project UIDB/04292/2020 awarded to MARE and through project LA/P/0069/2020 granted to the Associate Laboratory ARNET”. FCT also supported this study through the individual contract attributed to Bernardo R. Quintella (2020.02413.CEECIND and the PhD scholarships attributed to Ana Filipa Belo (SFRH/BD/123434/2016) and Esmeralda Pereira (SFRH/BD/121042/2016).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Data is available from correspondence author, upon reasonable request.

Conflicts of Interest

The authors declare no conflict of interest.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Belo, A.F.; Mateus, C.S.; Quintella, B.R.; Pereira, E.; Moreira, A.; Oliveira, R.; Batista, C.; Almeida, P.R.d. Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River. Biol. Life Sci. Forum 2022, 13, 126. https://doi.org/10.3390/blsf2022013126

AMA Style

Belo AF, Mateus CS, Quintella BR, Pereira E, Moreira A, Oliveira R, Batista C, Almeida PRd. Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River. Biology and Life Sciences Forum. 2022; 13(1):126. https://doi.org/10.3390/blsf2022013126

Chicago/Turabian Style

Belo, Ana Filipa, Catarina Sofia Mateus, Bernardo Ruivo Quintella, Esmeralda Pereira, André Moreira, Roberto Oliveira, Carlos Batista, and Pedro Raposo de Almeida. 2022. "Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River" Biology and Life Sciences Forum 13, no. 1: 126. https://doi.org/10.3390/blsf2022013126

APA Style

Belo, A. F., Mateus, C. S., Quintella, B. R., Pereira, E., Moreira, A., Oliveira, R., Batista, C., & Almeida, P. R. d. (2022). Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River. Biology and Life Sciences Forum, 13(1), 126. https://doi.org/10.3390/blsf2022013126

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