HISTOLOGICAL ANALYSES OF GONAD DEVELOPMENT IN FEMALE SPINY-CHEEK CRAYFISH ORCONECTES LIMOSUS RAF.
Dorota Juchno*, Łucjan Chybowski**
*University of Warmia and Masury in Olsztyn, Poland
**The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn, Poland
ABSTRACT. Histological analyses were preformed to investigate the annual cycle of the ovaries of female spiny-cheek crayfish Orconectes limosus Raf. (Crustacea). In May, the crayfish ovaries were filled mainly with oocytes in the initial stage of development (previtellogenic oocytes). The histological picture of the ovaries indicated the presence of empty follicles and mature oocytes undergoing resorption. In the summer months, the volume of the oocytes gradually increased and surplus substances material began to be synthesized (phase I or endogenous vitellogenesis). The histological picture of the ovaries in August was varied; some of them contained previtellogenic and vitellogenic oocytes in phase I, while others contained mainly oocytes in phase II of vitellogenesis when the cytoplasm fills with yolk and lipid globules. In fall, winter and spring the ovaries of crayfish O. limosus were filled mainly with oocytes in phase II of vitellogenesis; these were gradually increasing in volume. The annual gonadosomatic index (GSI) was calculated in the range of 0.41 to 5.83. The percentage of previtellogenic to vitellogenic oocytes prior to spawning was 23:77, and following spawning it was 70:30.
Key words: SPINY-CHEEK CRAYFISH (ORCONECTES LIMOSUS), REPRODUCTIVE CYCLE, OOGENESIS, GONADOSOMATIC INDEX
Dorota Juchno, Uniwersytet Warmińsko-Mazurski, Katedra Zoologii, ul. Oczapowskiego 5, 10-719 Olsztyn; Tel./Fax:+48 (89) 5233261; e-mail: firstname.lastname@example.org