Investigation on fecundity, follicles and free embryo size of pond-reared pike (Esox lucius) of different age and size

Abstract

The purpose of the present study is to investigate the gonadosomatic index (GSI %), the absolute and relative fecundity of one-year-old pike weighing over 400 g and at the same time to study the dependence between the egg size and the size, behavior and vitality of the free embryos obtained from one-and two-yearold spawners. The study involved two weight groups of females, differing in age and body weight and length-one-year-old (W = 514 g, SL = 36.1 cm) and two-year-old matured pike (W = 1454 g, SL = 49.3 cm). Ovary samples were fixed and egg follicles containing maturing oocytes counted and weight. The weight and length of the free embryos from semi-artificial spawning were measured. The results showed that, when raising this species under farmed conditions, more than 40% (in rarer cases 90%) of one-year-old pike females reached over 400 g and 35 cm (SL) and reached puberty. Absolute fecundity of 15,030 follicles (30 follicles per gram body weight) was observed; the GSI was nearly 15% and the follicle weight reached 3.7 mg. This data differs significantly from that obtained from the larger two-year-old fishes: absolute fecundity 41,363 follicles (28 follicles per gram body weight), GSI nearly 20%, follicle weight 5.8 mg. Results showed that the different follicle size determines the free-embryo size. A positive linear correlation was found between the egg follicle weight and the free-embryos weight (r = 0.7143). The free embryos obtain from the one-and two-year-old spawners differed significantly both in terms of their weight (7.13 mg against 10.61 mg) and total length (0.81 cm against 0.97 cm), the differences being 1.5-and 1.2-fold, respectively.

Effects of weaning time, light regime, and stocking density on growth, condition, survival, and cannibalism rates in northern pike (Esox lucius L.) larvae and early juveniles under intensive culture

“…The northern pike, Esox lucius L., a fish species widely distributed in most water bodies in the Northern Hemisphere (Lucas, 1996), can influence the abundance and distribution of many species (Hubenova et al, 2007;Craig, 2008). It is promising for inland aquaculture diversification (Samarin et al, 2016) because of its high-quality meat and popularity in commercial fishing and angling (Salam and Davies, 1994;Bondarenko et al, 2015b).…”

Does constant photoperiod inhibit the onset of the reproductive cycle in northern pike (Esox lucius) males?

“…The northern pike, Esox lucius (L., 1758), is a keystone piscivorous species in cool-water habitats that can influence species composition, abundance and distribution of many species (Balik et al 2006;Hubenova et al 2007;Craig 2008). It is one of the few predatory fish species that are most preferred by anglers throughout Europe, and it is intensively fished because of its flesh quality (Billard 1983;FAO 2014).…”