TURKISH JOURNAL OF VETERINARY & ANIMAL SCIENCES

The common cuttlefish (Sepia officinalis) is known as one of the economically important species in the classis Cephalopoda. In this study, from October 2000 to April 2002, 674 cuttlefish were collected monthly from the surroundings of Homa lagoon (in the Aegean Sea). In order to determine reproductive behaviors and spawning season of S. officinalis species, the gonad stages of both sexes and the seasonal gonadosomatic index values were determined. It was observed that the spawning period of S. officinalis covers the whole year with two maximum peaks in March and June

Reproductive strategies in female polar and deep-sea bobtail squid genera Rossia and Neorossia (Cephalopoda: Sepiolidae)

Female reproductive features have been investigated in five polar and deep-sea bobtail squid genera Rossia and Neorossia (R. macrosoma, R. moelleri, R. pacifica, N.c. caroli and N.c. jeannae). These species are characterized by asynchronous ovary maturation, very large eggs (>10% ML), fecundity of several hundred oocytes, very high reproductive output, and continuous spawning with low batch fecundity. This adaptive complex of reproductive traits evolved in these small animals as an optimum strategy for polar and deep-water habitats

Are introduced gibel carp Carassius gibelio in Turkey more invasive in artificial than in natural waters?

The underlying mechanisms responsible for ecological plasticity and consequent invasive character of non-native freshwater fish species, variations in growth and life history traits in gibel carp Carassius gibelio (Bloch) were compared in natural and artificial water bodies of Turkey. Females significantly outnumbered males in all natural and most artificial waters. Discriminate function analysis differentiated gibel populations into three separate groups (natural lakes, artificial water bodies and running waters), with significant differences among separated groups in growth index, standard length and age at maturity, relative fecundity and gonado-somatic index, but not in egg diameter and both generalised and relative condition. Growth features (e.g. growth index and relative condition) and reproductive features (e.g. relative and absolute fecundity) positively correlated with water body area. No correlations were found for any growth or life history trait with depth, latitude and altitude. With the exception of smaller size at maturity, all traits were higher in populations from artificial water bodies than those inhabiting running waters, suggesting gibel carp is required to exert more reproductive effort to invade natural ecosystems than artificial waters