Some aspects of the reproductive biology of the twaite shad, Alosa fallax (Lacépède, 1803), in the River Ulla (Northwest of the Iberian Peninsula)
David
J.
Nachón1*,
Sandra
Barca1, 2,
Sergio
Silva1,
Rufino
Vieira-Lanero2,
María
J.
Servia3,
Lorena
Lago1,
María
T.
Couto1,
Pablo
Gómez1,
Carlos
Morquecho1,
María
C.
Cobo1 and
Fernando
Cobo1, 2
-
1
Universidade de Santiago de Compostela, Departamento de Zooloxía e Antropoloxía Física, Spain
-
2
Universidade de Santiago de Compostela, Estación de Hidrobioloxía “Encoro do Con”, Spain
-
3
Universidade de A Coruña, Departamento de Bioloxía Animal, Bioloxía Vexetal e Ecoloxía, Spain
Evaluation of fecundity is a key step to quantify the reproductive potential of individual fish and to understand the stock-recruitment relationship, increasing the knowledge of the state of a stock and improving the assessment of the spawning stock biomass. For the present work we investigated the fecundity and gonad development in anadromous female twaite shad, Alosa fallax (Lacépède, 1803), during the upstream spawning migration in the River Ulla. Thirty-four females were sampled with trammel nets between April and June 2011 in seating areas for this species, located at 24 km and 20 km from the Atlantic Ocean respectively. Fish were lengthed to the nearest millimetre, weighed to the nearest gram and aged by using scales. Factor condition (K) was estimated as K= (TW/TL^3)*100 where TW is fish total weight (g) and TL is fish total length (cm). The ovaries from each female were removed and weighted to the nearest 0.01 gram. Approximately one gram samples were taken from the anterior, central and posterior regions of each ovary and preserved in 70 % ethanol. The number of eggs in each subsample was counted and the fecundity computed from the mean. Individual fecundity (F) was computed and F was divided by the weight of the fish to estimate relative fecundity (FR). Also the gonadosomatic index (GSI) was calculated to assess changes in fish maturity and spawning stage during the upstream migration. Female age ranged from 4 to 7 years and values of TL, TW, K and GSI were [mean ± SE (range)]: 493 ± 7.3 mm (408-562 mm); 1,112 ± 53.7 g (592-1,626 g); 0.91 ± 0.02 (0.67-1.09) and 12.5 ± 0.47 (6.6-21.4) respectively. The value of fecundity (F) was [mean ± SE (range)]: 96,471 ± 6,493 oocytes (24,962 to 182,154 oocytes), while the relative fecundity (Fr) was [mean ± SE (range)]: 87,142 ± 3,592 oocytes (25,319 to 129,189 oocytes). A significant correlation (Spearman´s ρ test, p<0.05) between fecundity and all parameters has been determined. As observed in previous studies variables that best correlated with fecundity were the TW (correlation coefficient: 0.793), K (correlation coefficient: 0.640) and TL (correlation coefficient: 0.612).
Acknowledgements
Part of this study has been carried out in the laboratories of the Station of Hydrobiology of the USC “Encoro do Con” at Vilagarcía de Arousa.
Keywords:
NW Iberian Peninsula,
Alosa fallax,
Upstream migration,
Reproductive biology,
fecundity
Conference:
XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015.
Presentation Type:
Poster Presentation
Topic:
Life Cycles, Migration and Connectivity
Citation:
Nachón
DJ,
Barca
S,
Silva
S,
Vieira-Lanero
R,
Servia
MJ,
Lago
L,
Couto
MT,
Gómez
P,
Morquecho
C,
Cobo
MC and
Cobo
F
(2015). Some aspects of the reproductive biology of the twaite shad, Alosa fallax (Lacépède, 1803), in the River Ulla (Northwest of the Iberian Peninsula).
Front. Mar. Sci.
Conference Abstract:
XV European Congress of Ichthyology.
doi: 10.3389/conf.FMARS.2015.03.00135
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
27 Nov 2015;
Published Online:
27 Nov 2015.
*
Correspondence:
Mr. David J Nachón, Universidade de Santiago de Compostela, Departamento de Zooloxía e Antropoloxía Física, Santiago de Compostela, Spain, davidjose.nachon@gmail.com