Türkiye Denizleri ve İç Sularında Avlanan Türlerin ... - Greenpeace

2008
Age Growth, Reproduction and Mortality of Tub Gurnard (Chelidonichthys lucernus Linnaeus,
1758) Inhabiting in Babadıllimanı Bight (Northeastern Mediterranean Coast of Turkey).
Çiçek, E., Avşar, D., Özyurt, C.E., Yeldan, H., Manaşırlı, M.
Journal of Biological Sciences 8 (1): 155-160.
Abstract: This study was carried out between May 1999 and April 2000 in Babadillimani
Bight, located in the Western entrance of Mersin Bay. A total of 228 specimens were trawled
by monthly sampling and they consisted of 49.56% females, 46.49% males and 3.95%
juveniles. Age composition varied from 0 to V. The mean total length and weight for females,
males and combined sexes were calculated as 15.12±4.36 cm-39.85±38.55 g, 15.11±4.51 cm to
40.71±38.69 g and 14.82±4.71 cm to 39.24±38.63 g, respectively. The length-weight
relationships were W = 0.0114*L 2.9179 for females, W = 0.0094*L 2.9883 for males and W =
0.0129*L 2.8735 for combined sexes. The von Bertalanffy growth parameters were estimated as
L ∞ = 46.42 cm, W ∞ = 832.13, K = 0.157 year -1 and t o = -1.569 year for females, L ∞ = 56.77 cm,
W ∞ = 1728.32, K = 0.121 year -1 and t o = -1.646 year for males and L ∞ = 42.25 cm, W 8 =
605.90, K = 0.196 year -1 and t o = -1.351 year for combined sexes. According to monthly
changes of mean Gonadosomatic Index values, spawning occurs between February and May.
Mean fecundity was calculated as 77010±17622. In additionally, length-fecundity and weightfecundity
relationships were estimated as F = 1898*L 1.156 (r 2 = 0.4077) and F = 242*W+43072
(r 2 = 0.4827), respectively. Total mortality rate (Z) was estimated 1.19, fishing mortality (F)
was calculated as 1.09 and exploitation rate (E) was estimated as 0.90 by using mortality rates.
Key words: Chelidonichthys lucernus, fecundity, length-weight relationships, Mersin Bay, tub
gurnard
2008
Spatio-temporal pattern of bluefin tuna (Thunnus thynnus L. 1758) gonad maturation across
the Mediterranean Sea.
Heinisch, G., Corriero, A., Medina, A., Abascal, F.J., de la Serna, J.M., Vassallo-Agius, R.,
Belmonte Ríos, A., García, A.,de la Gándara, F., Fauvel, C., Bridges, C.R., Mylonas, C.C.,
Karakulak, S., Oray, I., De Metrio, G., Rosenfeld, H., Gordin, H.
Mar. Biol. 154:623-630.
Abstract: Atlantic bluefin tuna (BFT; Thunnus thynnus) is a migrating species straddling the
North Atlantic Ocean and Mediterranean Sea. It is assumed that this species is divided into a
western and an eastern stock, which spawn in the Gulf of Mexico and the Mediterranean Sea,
respectively. To learn more about the reproductive behavior of the eastern BFT stock, we
tracked gonadal development in adult fish that were sampled between April and July during
three consecutive years (2003–2005). Sampling campaigns were carried out using common
fishing methods at selected locations within the Mediterranean Sea, namely Levantine Sea,
Malta, and Balearic Islands. An additional sampling point, Barbate, was situated northwest of
the Straits of Gibraltar along the Atlantic coast. Morphometric parameters such as the total
body mass (MB) and the weights of the gonads (MG) were recorded, and the respective
gonadosomatic index (GSI) values were calculated. The data collected revealed two important
trends: (1) GSI values are higher in fish caught in the eastern rather than the western locations
across the Mediterranean Sea, and (2) the GSI reaches maximum values between late May and
early June in Levantine Sea (eastern Mediterranean Sea), and only 2 and 4 weeks later in the
central (Malta) and western (Balearic Islands) locations, respectively. The advanced gonadal
development in BFT correlates well with higher sea surface temperatures. Our findings also
distinguish the northern Levantine Sea BFT population (mean MB 78.41 ± 4.13 kg), and the