Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia
This work compiles hydroacoustic recordings and catch data over Senegambia (Senegal and The Gambia) from assessment surveys on the major clupeid species to identify sources of bias in abundance estimates caused by their horizontal distribution. The latitudinal distribution of small pelagic fish is o...
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| Format: | Article |
| Language: | English |
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EDP Sciences
2018-01-01
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| Series: | Aquatic Living Resources |
| Subjects: | |
| Online Access: | https://www.alr-journal.org/articles/alr/full_html/2018/01/alr170084/alr170084.html |
| _version_ | 1797700808182071296 |
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| author | Sarré Abdoulaye Krakstad Jens-Otto Brehmer Patrice Mbye Ebou Mass |
| author_facet | Sarré Abdoulaye Krakstad Jens-Otto Brehmer Patrice Mbye Ebou Mass |
| author_sort | Sarré Abdoulaye |
| collection | DOAJ |
| description | This work compiles hydroacoustic recordings and catch data over Senegambia (Senegal and The Gambia) from assessment surveys on the major clupeid species to identify sources of bias in abundance estimates caused by their horizontal distribution. The latitudinal distribution of small pelagic fish is often well known, while their “across shelf” distribution on the continental shelf is less understood. The southern part of the Senegambian shelf has a wide shallow water (<10 m) area that makes up 20% (1500 NM2) of the total shelf surface, while the northern part accounts for 3% (200 NM2). These areas are not assessed by conventional fisheries acoustics surveys and therefore increase the uncertainty of the assessment of these species. Our findings show that this likely introduces a bias in the assessment of Sardinella maderensis, while for S. aurita no major estimation-error is caused by their horizontal distribution. The data confirm that Ethmalosa fimbriata and Ilisha africana are challenging to assess by conventional surveys, due to their mostly inshore distribution. We emphasise the usefulness of assessing S. aurita through fisheries independent hydroacoustic surveys, and propose alternative methods to survey shallow water areas to reduce biases in biomass estimates and distribution mapping. |
| first_indexed | 2024-03-12T04:27:57Z |
| format | Article |
| id | doaj.art-7b2c46dbe03546ec8b15dcf757a51374 |
| institution | Directory Open Access Journal |
| issn | 1765-2952 |
| language | English |
| last_indexed | 2024-03-12T04:27:57Z |
| publishDate | 2018-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | Aquatic Living Resources |
| spelling | doaj.art-7b2c46dbe03546ec8b15dcf757a513742023-09-03T10:15:43ZengEDP SciencesAquatic Living Resources1765-29522018-01-0131910.1051/alr/2017049alr170084Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The GambiaSarré Abdoulaye0Krakstad Jens-Otto1https://orcid.org/0000-0003-1685-6236Brehmer Patrice2https://orcid.org/0000-0001-8949-9095Mbye Ebou Mass3Centre de Recherche Océanographique de Dakar − Thiaroye (CRODT)Institute of Marine Research (IMR)Centre de Recherche Océanographique de Dakar − Thiaroye (CRODT)Ministry of Fisheries, Water Resources and National Assembly Matters, Gambia, Fisheries Department (FD)This work compiles hydroacoustic recordings and catch data over Senegambia (Senegal and The Gambia) from assessment surveys on the major clupeid species to identify sources of bias in abundance estimates caused by their horizontal distribution. The latitudinal distribution of small pelagic fish is often well known, while their “across shelf” distribution on the continental shelf is less understood. The southern part of the Senegambian shelf has a wide shallow water (<10 m) area that makes up 20% (1500 NM2) of the total shelf surface, while the northern part accounts for 3% (200 NM2). These areas are not assessed by conventional fisheries acoustics surveys and therefore increase the uncertainty of the assessment of these species. Our findings show that this likely introduces a bias in the assessment of Sardinella maderensis, while for S. aurita no major estimation-error is caused by their horizontal distribution. The data confirm that Ethmalosa fimbriata and Ilisha africana are challenging to assess by conventional surveys, due to their mostly inshore distribution. We emphasise the usefulness of assessing S. aurita through fisheries independent hydroacoustic surveys, and propose alternative methods to survey shallow water areas to reduce biases in biomass estimates and distribution mapping.https://www.alr-journal.org/articles/alr/full_html/2018/01/alr170084/alr170084.htmlfish distributionethmalosa fimbriatailisha africanasardinella spp.west africa |
| spellingShingle | Sarré Abdoulaye Krakstad Jens-Otto Brehmer Patrice Mbye Ebou Mass Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia Aquatic Living Resources fish distribution ethmalosa fimbriata ilisha africana sardinella spp. west africa |
| title | Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia |
| title_full | Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia |
| title_fullStr | Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia |
| title_full_unstemmed | Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia |
| title_short | Spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of Senegal and The Gambia |
| title_sort | spatial distribution of main clupeid species in relation to acoustic assessment surveys in the continental shelves of senegal and the gambia |
| topic | fish distribution ethmalosa fimbriata ilisha africana sardinella spp. west africa |
| url | https://www.alr-journal.org/articles/alr/full_html/2018/01/alr170084/alr170084.html |
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