Por favor, use este identificador para citar o enlazar este ítem: http://dspace.azti.es/handle/24689/612
Ficheros en este ítem:
No hay ficheros asociados a este ítem.
Título : A re-evaluation of the spawning fraction estimation procedures for Bay of Biscay anchovy, a species with short interspawning intervals
Autor : Uriarte, Andres; Alday, Ana; Santos, Maria; Motos, Lorenzo
Citación : FISHERIES RESEARCH, 2012, 117, 96-111
Resumen : The estimation procedures of the spawning fraction (S) of the Bay of Biscay anchovy (Engraulis encrasicolus), a species with short spawning intervals, have been revised using the samples collected in 14 surveys for the application of the daily egg production method in the period 1990-2007. Towards this aim, the procedure to assign mature females to daily spawning classes was first improved by incorporating all the available knowledge on final oocyte maturation and degeneration of post-ovulatory follicles (POFs) in a matrix system which defines the probabilities of females with either of these histological indicators belonging to pre- and post-spawning daily classes according to the time of capture. Subsequently several S estimators and their biases were evaluated: The proportion of day\_0 and day\_1 spawners showed a high consistency over a 24-hour cycle around the mean S value of 0.395 (CV = 18\%), although some oversampling of day\_0 females, up to 0.48, was observed around peak spawning time (at 23:00 hours). Individual daily spawning classes had a clumped distribution, resulting in strong negative correlation (-0.73) between day\_0 and day\_1 spawners. For all these features the mean proportion of day\_0 and day\_1 S(0 + 1), was practically unbiased and slightly more precise than the traditional S(1) corrected estimator (based upon the proportion of day\_1 females, corrected for oversampling of day\_0). The new estimates were very similar throughout the study period and were independent of the fishing gear or sampling time. Female size had a small but significant influence on S. In support of the high spawning fraction recorded, it is shown that many females received a double allocation to a pre and a post spawning daily class; this allowed an alternative estimation of S based upon the reciprocal of the individual spawning frequencies of females which produced a result very consistent with the other S estimators. (C) 2011 Elsevier B.V. All rights reserved.
Palabras clave : Spawning fraction; Post-ovulatory follicles; Final oocyte maturation; Reproduction; Anchovy; DAILY EGG-PRODUCTION; BATCH FECUNDITY; REPRODUCTIVE PARAMETERS; SARDINA-PILCHARDUS; JAPANESE ANCHOVY; POSTOVULATORY FOLLICLES; MEDITERRANEAN SARDINE; SCOMBER-JAPONICUS; ENGRAULIS-RINGENS; PACIFIC SARDINE
Fecha de publicación : 2012
Editorial : ELSEVIER SCIENCE BV
Tipo de documento: Article
Idioma: Inglés
DOI: 10.1016/j.fishres.2011.03.002
URI : http://dspace.azti.es/handle/24689/612
ISSN : 0165-7836
Patrocinador: Department of Agriculture, Fishing and Food of the Basque Government
European Commission UNCOVER [022717 (SSP 8)]
Agricultural and Fisheries Department of the Basque Country
Aparece en las tipos de publicación: Artículos científicos



Los ítems de DSpace están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.