Maternal effects on fecundity and egg quality of the Patagonian stock of Argentine Hake (Merluccius hubbsi)

Abstract

Abstract-The influences of age, size, and condition of spawning females on fecundity and oocyte quality were analyzed for the Patagonian stock of Argentine Hake (Merluccius hubbsi). Samples of mature females were collected in the spawning area as part of 2 research surveys conducted in January 2010 and 2011, during the peak of the reproductive season. Batch fecundity (BF) ranged between 40,500 (29 cm total length [TL]) and 2,550,000 (95 cm TL) hydrated oocytes, and was positively correlated with TL, gutted weight, age, hepatosomatic index (HSI), and the relative condition factor (Kn). Relative fecundity ranged between 85 and 1040 hydrated oocytes g -1 and showed significant positive relationships with gutted weight, HSI, and Kn; however, coefficients of determination were low for all regressions. Dry weights of samples of 100 hydrated oocytes ranged between 1.8 and 3.95 mg and were positively correlated with all variables analyzed, including batch and relative fecundity. Multiple regression models created with data of the morphophysiological characteristics of females supported maternal influences on fecundity and egg weights. Within the studied size range (29-95 cm TL), larger individuals had better somatic and egg condition, mainly revealed by higher HSI and hydrated oocytes with larger oil droplets (275.71µm [standard error 1.49]). These results were associated with the higher feeding activity of larger females during the spawning season in comparison with the feeding activity of young individuals (<5 years old); the better nutritional state of larger females, assumed to result from more feeding, was conducive to greater production of high-quality eggs.

Effect of nursery ground variability on condition of age 0+ year Merluccius hubbsi

“…Results on condition of age 0+ year M. hubbsi are presented for the first time for the Patagonian stock of the species within their main nursery ground in the Argentinean continental shelf, by a combination of different indices. Data are novel, considering that condition studies of exploited species in the ACS have focused either on Engraulis anchoita Hubbs & Marini 1935 larvae (Díaz et al ., ), or M. hubbsi larvae (Díaz et al ., ) and adults (Leonarduzzi et al ., ; Macchi et al ., ), with only a previous record for age 0+ year M. hubbsi solely based on morphology (Prenski & Angelescu, ). Despite the lack of previous local data to establish a comparison, our estimations closely agree with results on related age 0+ year gadoid species.…”

Maternal size, not age, influences egg quality of a wild, protogynous coral reef fish Plectropomus leopardus

“…The quantity and quality of eggs is often strongly influenced by the female size and age structure of a population; larger, older females often have greater batch fecundity (Sadovy 1996), spawn more frequently (Lowerre- Barbieri et al 2009), have a longer spawning season (Claramunt et al 2007) and produce better quality eggs and larvae (Berkeley et al 2004a) than smaller, younger conspecifics. Female body condition may also influence egg quality, with the hepatosomatic index (HSI) commonly used as an indicator, because of the liver's ability to store high levels of lipids used in egg production (Berkeley et al 2004a, Macchi et al 2013. Maternal effects on egg quality can have important implications for the reproductive potential of fished stocks because age or size truncation of a population through the removal of larger and older females by fishing can cause a greater reduction in the reproductive potential of that population than just a reduction in mature female biomass (Berkeley et al 2004b, Venturelli et al 2009, Hixon et al 2014.…”

Effects of skipped spawning on the reproductive potential of Argentine hake (Merluccius hubbsi)

“…In Argentine hake, it seems that the overestima-tion of reproductive potential could be even lower than expected because in this species, females that would skip spawning are primarily young individuals. Macchi et al (2006Macchi et al ( , 2013 suggested that young (<5 years old) female Argentine hake produce eggs of poorer quality than eggs spawned by older females. In addition, it was reported that the extent of the spawning season in young females of this species is shorter than that in old individuals (>5 years old), and a lower number of spawning events occur during the reproductive season (Macchi et al, 2004).…”

“…The coefficients were compared by using an χ 2 test according to Aubone and Wöhler. 2 In the case of the August surveys, we had only data for TL and gonad maturity stage from samples of females collected in , 2007, 2011, 2012and 2013. Using this information, we constructed lengthbased maturity ogives for August of those years, and the models obtained were compared with the maturity ogives estimated using data from January of the same year, during the previous spawning peak.…”