Trophic signatures of small-scale fishing gears: implications for conservation and management
We quantified the ecosystem effects of small-scale gears operating in southern European waters (Portugal, Spain, Greece), based on a widely accepted ecosystem measure and indicator, the trophic level (TL). We used data from experimental fishing trials during 1997 to 2000. We studied a wide range of...
Published in: | Marine Ecology Progress Series |
---|---|
Main Authors: | , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2012
|
Subjects: | |
Online Access: | http://hdl.handle.net/10498/14808 https://doi.org/10.3354/meps333117 |
id |
ftunivcadiz:oai:rodin.uca.es:10498/14808 |
---|---|
record_format |
openpolar |
spelling |
ftunivcadiz:oai:rodin.uca.es:10498/14808 2023-05-15T17:41:45+02:00 Trophic signatures of small-scale fishing gears: implications for conservation and management Stergiou, Konstantinos I. Moutopoulos, Dimitrios K. Hernando, J.A. Erzini, Karim Biología 2012-07-05T10:18:24Z application/pdf http://hdl.handle.net/10498/14808 https://doi.org/10.3354/meps333117 eng eng 0171-8630 http://hdl.handle.net/10498/14808 doi:10.3354/meps333117 Attribution-NonCommercial-NoDerivs 3.0 Unported info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/3.0/ CC-BY-NC-ND Marine Ecology Progress Series 2007. Vol. 333: 117–128. Trophic level Trophic signatures Gill nets Trammel nets Longlines Indicators Northeast Atlantic Ocean Mediterranean Sea info:eu-repo/semantics/article 2012 ftunivcadiz https://doi.org/10.3354/meps333117 2023-02-24T08:01:16Z We quantified the ecosystem effects of small-scale gears operating in southern European waters (Portugal, Spain, Greece), based on a widely accepted ecosystem measure and indicator, the trophic level (TL). We used data from experimental fishing trials during 1997 to 2000. We studied a wide range of gear types and sizes: (1) gill nets of 8 mesh sizes, ranging from 44 to 80 mm; (2) trammel nets of 9 inner panel mesh sizes, ranging from 40 to 140 mm; and (3) longlines of 8 hook sizes, ranging from Nos. 15 (small) to 5 (large). We used the number of species caught per TL class for constructing trophic signatures (i.e. cumulative TL distributions), and estimated the TL at 25, 50 and 75% cumulative frequency (TL25, TL50, TL75) and the slopes using the logistic function. We also estimated the mean weighted TL of the catches (TLW). Our analyses showed that the TL characteristics of longlines varied much more than those of gill and trammel nets. The longlines of large hooks (Nos. 10, 9, 7, 5) were very TL selective, and their trophic signatures had very steep slopes, the highest mean TL50 values, very narrow mean TL25 to TL75 ranges and mean TLW > 4. In addition, the mean number of TL classes exploited was smaller and the mean TL50 and TLW were larger for the longlines of small hooks (Nos. 15, 13, 12, 11) in Greek than in Portuguese waters. Trammel and gill nets caught more TL classes, and the mean slopes of their trophic signatures were significantly smaller than those of longlines as a group. In addition, the mean number of TL classes exploited, the mean TL50 and the TLW of gill nets were significantly smaller than those of trammel nets. We attribute the differences between longlines of small hooks to bait type, and the differences between all gear types to their characteristic species and size-selectivity patterns. Finally, we showed how the slope and the TL50 of the trophic signatures can be used to characterise different gears along the ecologically ‘unsustainable– sustainable’ continuum. Article in Journal/Newspaper Northeast Atlantic RODIN - Repositorio de Objetos de Docencia e Investigación de la Universidad de Cádiz Marine Ecology Progress Series 333 117 128 |
institution |
Open Polar |
collection |
RODIN - Repositorio de Objetos de Docencia e Investigación de la Universidad de Cádiz |
op_collection_id |
ftunivcadiz |
language |
English |
topic |
Trophic level Trophic signatures Gill nets Trammel nets Longlines Indicators Northeast Atlantic Ocean Mediterranean Sea |
spellingShingle |
Trophic level Trophic signatures Gill nets Trammel nets Longlines Indicators Northeast Atlantic Ocean Mediterranean Sea Stergiou, Konstantinos I. Moutopoulos, Dimitrios K. Hernando, J.A. Erzini, Karim Trophic signatures of small-scale fishing gears: implications for conservation and management |
topic_facet |
Trophic level Trophic signatures Gill nets Trammel nets Longlines Indicators Northeast Atlantic Ocean Mediterranean Sea |
description |
We quantified the ecosystem effects of small-scale gears operating in southern European waters (Portugal, Spain, Greece), based on a widely accepted ecosystem measure and indicator, the trophic level (TL). We used data from experimental fishing trials during 1997 to 2000. We studied a wide range of gear types and sizes: (1) gill nets of 8 mesh sizes, ranging from 44 to 80 mm; (2) trammel nets of 9 inner panel mesh sizes, ranging from 40 to 140 mm; and (3) longlines of 8 hook sizes, ranging from Nos. 15 (small) to 5 (large). We used the number of species caught per TL class for constructing trophic signatures (i.e. cumulative TL distributions), and estimated the TL at 25, 50 and 75% cumulative frequency (TL25, TL50, TL75) and the slopes using the logistic function. We also estimated the mean weighted TL of the catches (TLW). Our analyses showed that the TL characteristics of longlines varied much more than those of gill and trammel nets. The longlines of large hooks (Nos. 10, 9, 7, 5) were very TL selective, and their trophic signatures had very steep slopes, the highest mean TL50 values, very narrow mean TL25 to TL75 ranges and mean TLW > 4. In addition, the mean number of TL classes exploited was smaller and the mean TL50 and TLW were larger for the longlines of small hooks (Nos. 15, 13, 12, 11) in Greek than in Portuguese waters. Trammel and gill nets caught more TL classes, and the mean slopes of their trophic signatures were significantly smaller than those of longlines as a group. In addition, the mean number of TL classes exploited, the mean TL50 and the TLW of gill nets were significantly smaller than those of trammel nets. We attribute the differences between longlines of small hooks to bait type, and the differences between all gear types to their characteristic species and size-selectivity patterns. Finally, we showed how the slope and the TL50 of the trophic signatures can be used to characterise different gears along the ecologically ‘unsustainable– sustainable’ continuum. |
author2 |
Biología |
format |
Article in Journal/Newspaper |
author |
Stergiou, Konstantinos I. Moutopoulos, Dimitrios K. Hernando, J.A. Erzini, Karim |
author_facet |
Stergiou, Konstantinos I. Moutopoulos, Dimitrios K. Hernando, J.A. Erzini, Karim |
author_sort |
Stergiou, Konstantinos I. |
title |
Trophic signatures of small-scale fishing gears: implications for conservation and management |
title_short |
Trophic signatures of small-scale fishing gears: implications for conservation and management |
title_full |
Trophic signatures of small-scale fishing gears: implications for conservation and management |
title_fullStr |
Trophic signatures of small-scale fishing gears: implications for conservation and management |
title_full_unstemmed |
Trophic signatures of small-scale fishing gears: implications for conservation and management |
title_sort |
trophic signatures of small-scale fishing gears: implications for conservation and management |
publishDate |
2012 |
url |
http://hdl.handle.net/10498/14808 https://doi.org/10.3354/meps333117 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_source |
Marine Ecology Progress Series 2007. Vol. 333: 117–128. |
op_relation |
0171-8630 http://hdl.handle.net/10498/14808 doi:10.3354/meps333117 |
op_rights |
Attribution-NonCommercial-NoDerivs 3.0 Unported info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/3.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.3354/meps333117 |
container_title |
Marine Ecology Progress Series |
container_volume |
333 |
container_start_page |
117 |
op_container_end_page |
128 |
_version_ |
1766143474738921472 |