Reproductive strategy of a primitive temperate notothenioid Eleginops maclovinus

Abstract

The reproductive biology of Eleginops maclovinus was examined in the Falkland Islands between October 2000 and December 2002. Males predominated at total lengths (L T ) of 10 to 52 cm and females at >53 cm L T . Length frequency analysis showed a bimodal distribution with females representing the larger mode for every month during the study period. Gonad histology revealed that 19% of the histological samples studied were considered to be those from hermaphrodites: morphologically as male gonads but containing protoplasmic oocytes. It was therefore concluded that E. maclovinus is a protandrous hermaphrodite. The size of first (male) maturation of E. maclovinus was 30Á73 cm L T . Males and females matured from August onwards and spawning occurred between September and December at depths of >40 m. Eleginops maclovinus has the smallest eggs and highest fecundity among the notothenioids. The highest potential fecundity was attained at maturity stage III with c. 48 million eggs. Because of further oocyte resorption, this value gradually decreased until the final fecundity ranged from 1Á1 to 7Á3 million eggs. Oocyte length frequencies in ovaries suggested that E. maclovinus was a batch spawner. Hydrated oocytes were found to contain a large perivitelline space indicating that the egg had a pelagic development. # 2005 The Fisheries Society of the British Isles

Somatic energy content and histological analysis of the gonads in Antarctic fish from the Scotia Arc

“…This species spawns partially in June in central to southern Chile (Panozo, 1996), and shows a protracted spawning season between September and December around the Islas Malvinas/Falkland Islands in waters of 30-100 metres depth. Each batch comprises between 1.1 and 7.3 million oocytes with a diameter of 1 to 1.2 mm (Brickle et al, 2005). Hence, taking into account the extended spawning period and the possible repetitive spawning of the non-Antarctic notothenioids vs. the usual single spawning of Antarctic notothenioids, Subantarctic waters obviously impose less severe constraints on the reproductive effort than Antarctic waters.…”

Genetic relationships between Atlantic and Pacific populations of the notothenioid fish Eleginops maclovinus: the footprints of Quaternary glaciations in Patagonia

“…Adults reach a maximum length of 80/90 cm (Brickle et al, 2005a;Licandeo et al, 2006) and are highly mobile, at least in aquaria (personal observations). E. maclovinus has been described as a protandrous hermaphrodite (Calvo et al, 1992;Brickle et al, 2005b;Licandeo et al, 2006) and is characterized by high fecundity and small pelagic eggs (Brickle et al, 2005b). Little is known about larval development of E. maclovinus, although it likely has extended pelagic phases, as found in many other notothenioid fishes.…”

Age, Growth Rates, Sex Change and Feeding Habits of Notothenioid Fish Eleginops Maclovinus from the Central-southern Chilean Coast

“…E. maclovinus has been described as a protandrous hermaphrodite (Calvo et al 1992;Panoso 1996;Brickle et al 2005a). Aspects related to its growth rates have been studied in different areas by Goztonyi (1974), Veas (1998) and Brickle et al (2005b).…”