Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna
Results of the analysis of information taken from fishing logbooks and samples obtained from the Mexican purse seine fleet are presented. This information was analyzed independently of the size of the ships and areas of operation. The study includes the time of beginning of sets and the time they we...
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Iniversidad Autónoma de Baja California
1992
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oai:cienciasmarinas.com.mx:article-8742020-06-05T23:44:43Z Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna Actividad de la flota atunera mexicana de cerco y el comportamiento alimenticio del atún aleta amarilla Ortega-García, S Galván-Magaña, F Arvizu-Martínez, J n/a n/a Results of the analysis of information taken from fishing logbooks and samples obtained from the Mexican purse seine fleet are presented. This information was analyzed independently of the size of the ships and areas of operation. The study includes the time of beginning of sets and the time they were made, the relationship between the number of sets and the time they were made and the monthly variation in 1985. A comparison is made between this information and food volume of yellowfin tuna. It was found that the sets of yellowfin were made almost entirely during daylight hours as observed from the two modal intervals in nearly all the months analyzed; the first one occurs during the morning and the second one during the afternoon. The minimum of sets was registered between 11:00-13:00 hours; only in one case out of the 12 analyzed did the minimum occur between 13:00-14:00 hours (May). Various degrees of gastric depletion were observed throughout the day. However, at 13:00 and 14:00 hours the stomachs were nearly empty, forcing the tuna to look for food in deeper waters, because at this time of day light penetration is maximal, thus leading to a descent of the prey and lowering the vulnerability of the tuna to the fishing fleet. This, in turn, could account for the lesser number of sets at this hour of the day. The most important preys were: red crab (Pleuroncodes planipes), cephalopods Argonauta sp., Dosidicus gigac, Symplectoteuthis ovalaniensis and Onychoteuthis banksii) and the Pacific mackerel (Scomber japonicus). Se presentan los resultados del análisis de la información procedente de las bitácoras de la flota atunera mexicana de cerco, misma que se analizó independientemente del tamaño de las embarcaciones y áreas de operación. El trabajo incluye las horas en las que se inician los lances de pesca de la flota, la relación que existe entre el número de lances y la hora en la que se realizaron éstos, así como su variación mensual durante 1985. La información anterior se compara con el grado de repleción gástrica de los estómagos de los atunes. Se encontró que los lances de atún aleta amarilla se realizaron casi en su totalidad durante las horas diurnas y se observa la presencia de dos modas en la mayoría de los meses analizados; la primera ocurre en el transcurso de la mañana y la otra por la tarde. El mínimo de lances se presenta por lo general entre las 11:00 y las 13:00 horas, excepto en el mes de mayo donde el mínimo se presentó de las 13:00 a las 14:00 horas. A lo largo del día se observan diferentes grados de repleción gástrica; sin embargo, de las 12:00 a las 14:00 horas el grado de llenado de los estómagos es mínimo, lo que quizá obliga al atún a buscar su alimento en aguas más profundas, ya que en estas horas la penetración de luz es mayor, al igual que el descenso de las presas, lo que disminuye la vulnerabilidad del atún aleta amarilla para la flota cerquera. Este suceso podría explicar por qué es menor el número de lances a esta hora del día. Las presas más importantes fueron: la langostilla (Pleuroncodes planipes), los cefalópodos (Argonauta sp., Dosidicus gigac, Symplectoteuthis ovalaniensis y Onychoteuthis banksii), y la macarela (Scomber japonicus). Iniversidad Autónoma de Baja California 1992-03-06 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado application/pdf https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/874 10.7773/cm.v18i1.874 Ciencias Marinas; Vol. 18 No. 1 (1992); 139-149 Ciencias Marinas; Vol. 18 Núm. 1 (1992); 139-149 2395-9053 0185-3880 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/874/797 |
| institution |
Ciencias Marinas |
| collection |
OJS |
| language |
eng |
| format |
Online |
| author |
Ortega-García, S Galván-Magaña, F Arvizu-Martínez, J |
| spellingShingle |
Ortega-García, S Galván-Magaña, F Arvizu-Martínez, J Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| author_facet |
Ortega-García, S Galván-Magaña, F Arvizu-Martínez, J |
| author_sort |
Ortega-García, S |
| title |
Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| title_short |
Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| title_full |
Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| title_fullStr |
Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| title_full_unstemmed |
Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| title_sort |
activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna |
| description |
Results of the analysis of information taken from fishing logbooks and samples obtained from the Mexican purse seine fleet are presented. This information was analyzed independently of the size of the ships and areas of operation. The study includes the time of beginning of sets and the time they were made, the relationship between the number of sets and the time they were made and the monthly variation in 1985. A comparison is made between this information and food volume of yellowfin tuna. It was found that the sets of yellowfin were made almost entirely during daylight hours as observed from the two modal intervals in nearly all the months analyzed; the first one occurs during the morning and the second one during the afternoon. The minimum of sets was registered between 11:00-13:00 hours; only in one case out of the 12 analyzed did the minimum occur between 13:00-14:00 hours (May). Various degrees of gastric depletion were observed throughout the day. However, at 13:00 and 14:00 hours the stomachs were nearly empty, forcing the tuna to look for food in deeper waters, because at this time of day light penetration is maximal, thus leading to a descent of the prey and lowering the vulnerability of the tuna to the fishing fleet. This, in turn, could account for the lesser number of sets at this hour of the day. The most important preys were: red crab (Pleuroncodes planipes), cephalopods Argonauta sp., Dosidicus gigac, Symplectoteuthis ovalaniensis and Onychoteuthis banksii) and the Pacific mackerel (Scomber japonicus). |
| publisher |
Iniversidad Autónoma de Baja California |
| publishDate |
1992 |
| url |
https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/874 |
| _version_ |
1715724022415622144 |
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