Tomasz Wandzel
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland
Key words: round goby, Neogobius melanostomus, gobiidae, fecundity, reproduction, Puck Bay, invasive species, Baltic Sea.
Abstract.
This work presents results of fecundity and reproduction
investigations of round goby, a species which is new to the Puck Bay. A
total of 728 fish were analyzed. The material for initial fecundity analyses
consisted of 135 chosen females with gonads in maturity stages IV and V
on the Maier scale. The longitudo totalis (l. t.) of the females
ranged from 7 cm to 22 cm. Analyses revealed that the majority of females
and males, even at a l. t. of 80-90 mm, were mature. In 1999, round
gobies began spawning in the Puck Bay in April and finished in late August
and early September of the same year. The absolute fecundity of female
round gobies ranging in length from 7.4 cm to 16.6 cm (average 12.4 cm)
was 89 to 3,841 spawn grains. It was determined that the relationship between
absolute fecundity Fa and l. t. (R = 0.888)
is nonlinear, while that between absolute fecundity and female body mass
GW (R = 0.877) is linear. The hypothetical, absolute fecundity of females
15 cm long was 3,036 eggs. The relative fecundity Fw
of round goby females ranged from 17 to 109 eggs/g of female body mass.