TY - JOUR
T1 - Catch efficiency of trawl nets used in surveys of the yellow squat lobster (Cervimunida johni) estimated by underwater filming records
AU - Ahumada, Mauricio
AU - QUEIROLO PALMA, DANTE
AU - Apablaza, Pedro
AU - Wiff, Rodrigo
AU - Flores, Andrés
N1 - Funding Information:
The authors express their gratitude to two anonymous reviewers for their valuable comments and suggestions and to Marcia Tomasoni C. and Ana Luíza Couto-Ziezkowski for processing the video records for the analysis. R. Wiff was partially funded by the project CONICYT, Chile PIA/BASAL FB0002. The present research was partially financed by funds from the projects of the Direct Stock Assessment of the Yellow Squat Lobster and Red Squat Lobster of 2015 and 2018, which were tendered by the Instituto de Fomento Pesquero and implemented by the Pontificia Universidad Católica de Valparaíso, Chile .
Funding Information:
The authors express their gratitude to two anonymous reviewers for their valuable comments and suggestions and to Marcia Tomasoni C. and Ana Lu?za Couto-Ziezkowski for processing the video records for the analysis. R. Wiff was partially funded by the project CONICYT, Chile PIA/BASAL FB0002. The present research was partially financed by funds from the projects of the Direct Stock Assessment of the Yellow Squat Lobster and Red Squat Lobster of 2015 and 2018, which were tendered by the Instituto de Fomento Pesquero and implemented by the Pontificia Universidad Cat?lica de Valpara?so, Chile.
Publisher Copyright:
© 2021 Elsevier B.V.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - Catch efficiency is an important index to relate observed density to the size of a population in the context of bottom trawl surveys. The estimation of catch efficiency is challenging because it involves independent measures of animals in the path of the bottom trawl. We estimated catch efficiency using an underwater camera system on three trawl fishing vessels used for estimating the density of the yellow squat lobster (Cervimunida johni) off central Chile. During 2015 and 2018, 54 hauls were analyzed, and a total of 20 h of filming were recorded. A total of 4,155 yellow squat lobster individuals were analyzed approaching the net in the path of the trawl, of which 2,330 (56%) were captured and 1,825 escaped underneath the groundrope. The median estimated ranges of catch efficiency varied between 0.81–0.90 for vessel 1, 0.15–0.72 for vessel 2 and 0–0.58 for vessel 3. According to a hierarchical generalized linear model (HGML), fishing vessels and mean depth of hauls showed significant differences in catch efficiency (p<0.05). The results were comparable with estimates available for other crustacean species, and differences among vessels can be associated with differences in rigging configurations. Discussion was focused on the processes affecting catch efficiency and how differential catchability among sampling vessels may bias the construction of spatially explicit density maps and further abundance estimates of yellow squat lobsters in Chile.
AB - Catch efficiency is an important index to relate observed density to the size of a population in the context of bottom trawl surveys. The estimation of catch efficiency is challenging because it involves independent measures of animals in the path of the bottom trawl. We estimated catch efficiency using an underwater camera system on three trawl fishing vessels used for estimating the density of the yellow squat lobster (Cervimunida johni) off central Chile. During 2015 and 2018, 54 hauls were analyzed, and a total of 20 h of filming were recorded. A total of 4,155 yellow squat lobster individuals were analyzed approaching the net in the path of the trawl, of which 2,330 (56%) were captured and 1,825 escaped underneath the groundrope. The median estimated ranges of catch efficiency varied between 0.81–0.90 for vessel 1, 0.15–0.72 for vessel 2 and 0–0.58 for vessel 3. According to a hierarchical generalized linear model (HGML), fishing vessels and mean depth of hauls showed significant differences in catch efficiency (p<0.05). The results were comparable with estimates available for other crustacean species, and differences among vessels can be associated with differences in rigging configurations. Discussion was focused on the processes affecting catch efficiency and how differential catchability among sampling vessels may bias the construction of spatially explicit density maps and further abundance estimates of yellow squat lobsters in Chile.
KW - Bottom trawl
KW - Catch efficiency
KW - Catchability
KW - Cervimunida johni
KW - Underwater video
KW - Yellow squat lobster
UR - http://www.scopus.com/inward/record.url?scp=85103344124&partnerID=8YFLogxK
U2 - 10.1016/j.rsma.2021.101744
DO - 10.1016/j.rsma.2021.101744
M3 - Article
AN - SCOPUS:85103344124
VL - 44
JO - Regional Studies in Marine Science
JF - Regional Studies in Marine Science
SN - 2352-4855
M1 - 101744
ER -