Reproductive studies of Anchoa marinii Hildebrand, 1943 (Actinopterygii: Engraulidae) in the nearby-coastal area of Mar Chiquita coastal lagoon, Buenos Aires, Argentina

Abstract

The aim of the present study provides the first results on the reproductive biology of the anchovy, Anchoa marinii, in a nearby-coastal area of Mar Chiquita coastal lagoon, 37º32'00"S 57º19'00"W, Argentina. To perform this, we employed mainly female gonads, at both microscopic and macroscopic levels. The oocyte diameter distribution and the microscopy analysis of oocytes, showed different batches of growing oocytes, suggesting that the anchovy is a multiple spawner, with constant oocytes recruitment all over the reproductive season. The batch fecundity ranged between 749 and 3,207 oocytes for females, and the relative fecundity ranged from 127 to 422 yolked oocytes per female gram (ovary free). The fecundity estimation has been made with yolked oocytes. No correlation between the fecundity estimation and female size and total weight (without ovary) has been found. The estimated L 50 values were 74.13 and 73.76 mm TL for females and males, respectively. Shoals of females in advanced maturity phase were recorded, between December to April in the study area. During this period a significant increase of species abundance was correlated with water temperature increase (above 16°C). This fact, together with the detection of post-ovulatory follicles, indicated the existence of reproductive events in the nearby-coastal area of Mar Chiquita coastal lagoon.El objetivo del presente trabajo es avanzar en la comprensión del ciclo de vida de la anchoa, Anchoa marinii, en relación a la franja submareal frente a la laguna costera Mar Chiquita, 37º32'00"S 57º19'00"W, Argentina. Para llevarlo a cabo se utilizaron gónadas, principalmente hembras, y se estudiaron a nivel macro y microscópico. El análisis microscópico de los ovarios evidenció la presencia de diferentes camadas de ovocitos, con un reclutamiento constante de ovocitos inmaduros durante la época reproductiva, relacionado con un patrón de puestas parciales. La fecundidad parcial arrojo valores entre 749 y 3207 ovocitos, y la fecundidad relativa estuvo comprendida entre 127 y 422 ovocitos por peso total libre de ovarios. Las estimaciones se realizaron a partir de ovarios con ovocitos vitelados. No se encontraron relaciones significativas entre las estimaciones de fecundidad y la talla o peso de las hembras. La talla de primera madurez se estimó en 74,13 mm para las hembras y 73,76 mm para los machos, en el área muestreada. La presencia de hembras en estadio de maduración avanzada fue muy abundante entre diciembre y abril, correlacionándose con elevada temperatura del agua (por encima de 16°C). Este hecho sumado a la detección de hembras con folículos post-ovulatorios indicarían que la anchoa, Anchoa marinii, presenta actividad reproductiva durante la temporada estival, en el submareal frente a la Laguna costera Mar Chiquita.

Reproduction of Brevoortia aurea (Spix & Agassiz, 1829) (Actinopterygii: Clupeidae) in the Mar Chiquita Coastal Lagoon, Buenos Aires, Argentina

“…Also, no significant correlation was found between the fecundity and the variables "weight" and "length". This fact was reported by Macchi & Acha (2000) for this species, but also for other species of Clupeiformes with similar reproductive strategies (López et al, 2013). The females used in this work correspond to the asymptote of infinity length, of the growth curve of Lopez-Cazorla (1985).…”

“…These values are much greater than those of the most important local species of Clupeiformes with similar reproductive strategies. For example, batch fecundity estimated of Anchoa marinii was 749 to 3,207 oocytes, (López et al, 2013). Rodrigues et al (2008) reported a batch fecundity of 570-2,026 oocytes for Ramnogaster arcuata specimens.…”

“…However, when comparing the relative fecundity of these species, it is noticeable that B. aurea presented the lowest values in comparison with those of the above mentioned species: 41-381 hydrated oocytes per gram of female (ovary free) for B. aurea, 127-422 oocytes for A. marinii (López et al, 2013); R. arcuata between 150 and 437 oocytes (Rodrigues et al, 2008) and E. anchoita with 574 oocytes (Pájaro et al, 1997). These differences could be due to the largest size of the hydrated oocytes of B. aurea (1000 to 1600 μm in this paper), in comparison with other local species of Clupeiformes (A. marinii; R. arcuata and E. anchoita) which are less than 1000 μm (Rodrigues et al, 2008;López et al, 2013;Pájaro et al, 1997). The size and number of eggs produced vary greatly among species and all of these traits have important consequences for survival.…”

Feeding habits of South American and sub‐Antarctic fur seals during their nonbreeding season in the southwestern Atlantic Ocean

“…The presence of A. marinii is closely associated with the cold waters transported by the Brazilian Coastal Current, similar to other engraulid species in the area (Franco et al, 2006). Based on the reconstructed length of fish consumed by SAFSs, it was observed that the majority of A. marinii individuals were mature (López et al, 2015).…”