Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards

Bycatch is a significant issue in global fisheries and understanding the length–weight relationships (LWR) of fish species can provide valuable insights for stock assessment and management efforts. In this study, we estimated the LWR of 74 fish species in trawl fleet discards from the Gulf of Cadiz,...

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Main Authors: Carlos Rodríguez-García, Jairo Castro-Gutiérrez, Ángel Rafael Domínguez-Bustos, Alberto García-González, Remedios Cabrera-Castro
Format: Article
Language:English
Published: MDPI AG 2023-04-01
Series:Fishes
Subjects:
Online Access:https://www.mdpi.com/2410-3888/8/5/222
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author Carlos Rodríguez-García
Jairo Castro-Gutiérrez
Ángel Rafael Domínguez-Bustos
Alberto García-González
Remedios Cabrera-Castro
author_facet Carlos Rodríguez-García
Jairo Castro-Gutiérrez
Ángel Rafael Domínguez-Bustos
Alberto García-González
Remedios Cabrera-Castro
author_sort Carlos Rodríguez-García
collection DOAJ
description Bycatch is a significant issue in global fisheries and understanding the length–weight relationships (LWR) of fish species can provide valuable insights for stock assessment and management efforts. In this study, we estimated the LWR of 74 fish species in trawl fleet discards from the Gulf of Cadiz, including 24 species for which LWR data had not been previously reported in this region. LWR was calculated from the formula <i>W = aL<sup>b</sup></i> where parameter <i>a</i> is the intercept of the equation, related to body shape, and parameter <i>b</i> is the slope, which indicates the type of growth of the species. A total of 20,007 individuals from 40 families were measured and weighed. The most abundant species were <i>Engraulis encrasicolus</i>, <i>Trachurus trachurus</i>, <i>Serranus hepatus</i>, <i>Sardina pilchardus</i>, <i>Capros aper</i>, and <i>Diplodus bellottii</i>, and the Sparidae family was the most represented with ten species. The parameter b, which represents the type of growth, ranged from 2.1607 to 3.7040. A positive allometric growth trend was observed in 64% of the species. The inclusion of individuals with a low sample size proved useful, particularly for first reports in a new study area. However, caution should be taken when using these data, as the estimates of the length–weight relationship for these species may be less precise. Further studies with larger sample sizes are needed to confirm the results and improve the accuracy of the estimates. Overall, our findings contribute to the understanding of the LWR of fish species in the Gulf of Cadiz, informing future research and management efforts in the region.
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spelling doaj.art-23c19c5bd43e46f6bcdfb8624cea856a2023-11-18T01:19:27ZengMDPI AGFishes2410-38882023-04-018522210.3390/fishes8050222Every Fish Counts: Challenging Length–Weight Relationship Bias in DiscardsCarlos Rodríguez-García0Jairo Castro-Gutiérrez1Ángel Rafael Domínguez-Bustos2Alberto García-González3Remedios Cabrera-Castro4Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus Río San Pedro, Universidad de Cádiz, 11510 Puerto Real, SpainDepartamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus Río San Pedro, Universidad de Cádiz, 11510 Puerto Real, SpainDepartamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus Río San Pedro, Universidad de Cádiz, 11510 Puerto Real, SpainDepartamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus Río San Pedro, Universidad de Cádiz, 11510 Puerto Real, SpainDepartamento de Biología, Facultad de Ciencias del Mar y Ambientales, Campus Río San Pedro, Universidad de Cádiz, 11510 Puerto Real, SpainBycatch is a significant issue in global fisheries and understanding the length–weight relationships (LWR) of fish species can provide valuable insights for stock assessment and management efforts. In this study, we estimated the LWR of 74 fish species in trawl fleet discards from the Gulf of Cadiz, including 24 species for which LWR data had not been previously reported in this region. LWR was calculated from the formula <i>W = aL<sup>b</sup></i> where parameter <i>a</i> is the intercept of the equation, related to body shape, and parameter <i>b</i> is the slope, which indicates the type of growth of the species. A total of 20,007 individuals from 40 families were measured and weighed. The most abundant species were <i>Engraulis encrasicolus</i>, <i>Trachurus trachurus</i>, <i>Serranus hepatus</i>, <i>Sardina pilchardus</i>, <i>Capros aper</i>, and <i>Diplodus bellottii</i>, and the Sparidae family was the most represented with ten species. The parameter b, which represents the type of growth, ranged from 2.1607 to 3.7040. A positive allometric growth trend was observed in 64% of the species. The inclusion of individuals with a low sample size proved useful, particularly for first reports in a new study area. However, caution should be taken when using these data, as the estimates of the length–weight relationship for these species may be less precise. Further studies with larger sample sizes are needed to confirm the results and improve the accuracy of the estimates. Overall, our findings contribute to the understanding of the LWR of fish species in the Gulf of Cadiz, informing future research and management efforts in the region.https://www.mdpi.com/2410-3888/8/5/222fisheriesbody lengthfish biometricsgrowthprofessional fleetmeasurements
spellingShingle Carlos Rodríguez-García
Jairo Castro-Gutiérrez
Ángel Rafael Domínguez-Bustos
Alberto García-González
Remedios Cabrera-Castro
Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
Fishes
fisheries
body length
fish biometrics
growth
professional fleet
measurements
title Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
title_full Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
title_fullStr Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
title_full_unstemmed Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
title_short Every Fish Counts: Challenging Length–Weight Relationship Bias in Discards
title_sort every fish counts challenging length weight relationship bias in discards
topic fisheries
body length
fish biometrics
growth
professional fleet
measurements
url https://www.mdpi.com/2410-3888/8/5/222
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