PRELIMINA RY RESULTS O N RA YED PEA RL O YSTER ( Pinc tada radiata , Le a c h 1814) SPA T C O LLEC TIO N A T KA RA NTINA ISLA ND IN IZMIR BA Y (TURKEY) *Department of Aquaculture, Fisheries Faculty, Ege University, Bornova-Izmir, 35100 Turkey E-mail: selcuk.yigitkurt@ege.edu.tr Selçuk Yiğitkurt*, Aynur Lök Figure 1. Pinctada radiata, Leach 1814. INTRO DUC TIO N Pe a rl o yste r Pinc tada radiata is o ne o f the im p o rta nt sp e c ie s in fa m ily Pte riid a e (Fig ure 1). Sp a t c o lle c tio n is the m o st im p o rta nt sta g e in the p e a rl c ulture . Sp a t c o lle c tio n a lso p ro vid e s a m e tho d o f c o lle c ting sm a ll fra g ile a nd c ryp tic sp e c ie s tha t a re o the rwise uno b ta ina b le . Re se e d ing a nd sto c k e nha nc e m e nt p ro g ra m m e s (Ho rtle a nd Cropp 1987, Robins- Troager and Dredge, 1993, Saudeco et al. 1994) also may be based on spat collection. There is no published data on the collection of pearl oyster Pinc tada radiata spat in Turkey. The aim of this study is to find the a nswe r o f the fo llo wing q ue stio n: Whic h c o lle c to r typ e is the suc c e sful to c o lle c t p e a rl o yste r sp a t in Ka ra ntina Isla nd , Izm ir Ba y? MA TERIA LS A ND METHO DS The study site at Karantina Island is located at 38°22''44N, North; 26°47''12E on the west side of Izmir Bay. The water depth is approximately 5 m at shallow water and the bottom is muddy sand. Twelve bag collectors (onion sack; polyethylene, 1,5 mm fiber size and 3x3 mm mesh size, 0,81 m²) and twelve mussel shell collectors (avarage lenght size of shell; 60.27±7.26 mm ) were suspended on longlines spaced one meter apart, approximately 1 m below the water surface. Each groups of collectors were deployed on June 2003, and two collectors from two type were taken for observation at the other months. Observation continued six months. The last samples of collectors was taken on December 2003. Chi-square (χ²) analysis was used to find d iffe re nc e s b e twe e n b a g a nd she ll c o lle c to rs. Diffe re nc e s we re c o nsid e re d sig nific a nt whe n p < 0.05. 0 5 10 15 20 25 30 Jun Jul Aug Se p Oct No v De c Ja n Fe b Mar Ap r May Te mp e ra ture (°C ) 35,7 35,8 35,9 36 36,1 36,2 36,3 36,4 36,5 36,6 Sa linity (‰ ) Te mp e ra ture (°C ) Sa linity (‰ ) RESULTS Hig he st- lo we st te m p e ra ture a nd sa linity wa s fo und a s 27 ºC-36.5 ppt in August 2003 and 12.5 ºC-36 ppt in December 2003 (Figure 2). TPM and Chlorophyll-a was found high value in August and September; and low va lue in July a nd De c e m b e r, re sp e c tive ly (Fig 3). The re wa s a sig nific ia nt d iffe re nc e in the to ta l a b und a nc e o f P. radiata between collector groups (p<0.05). 0 5 10 15 20 25 30 35 40 Jun Jul Aug Se p Oct No v Dec TPM (mg / l) 0 1 2 3 4 5 6 7 8 9 10 C hllo ro p hyll a (μ/ l) TPM (m g / l) C hlo ro p hyll a (μ/ l) Fig ure 2. Se a wa te r temperature (°C) and salinity (ppt) in June 2003 and May 2004 in Karantina Island. Fig ure 3. To ta l p a rtic ule m a tte r (TPM) a nd C hlo ro p hyll a d uring the stud y p e rio d . First se ttle m e nt wa s o b se rve d in A ug ust o n b a g a nd m usse l she ll c o lle c to rs tha t d e p lo ye d in June . A to ta l o f 57 P. radiata spat were collected at the bag collectors and 15 spat at the shell collectors during the study (Table 1). Diffe re nt sp e c ie s o b se rve d in she ll a nd b a g c o lle c to rs (Ta b le 2- 3). Ta b le 1. Num b e r a nd size d istrib utio n (% ) o f se ttle d p e a rl o yste r, Pinc tada radiata , spat on bag and mussel shell c o lle c to rs. Ta b le 2. The o the r sp e c ie s num b e r in She ll c o lle c to r. Ta b le 3. The o the r sp e c ie s num b e r in Ba g c o lle c to r. C O NC LUSIO N First settlement was observed in August, maximum spat obtained in November on both c o lle c to r g ro up s tha t d e p lo ye d in June . The re wa s a sig nific ia nt d iffe re nc e in the to ta l a b und a nc e o f P. radiata on shell and bag collectors (p<0.05). Ba g c o lle c to rs tha t m a d e o nio n sa c ks we re the m o st suc c e sful m a te ria l to c o lle c t p e a rl o yste r sp a t in Ka ra ntina Isla nd , Izm ir Ba y. REFERENC ES Hortle, M. E. & Cropp, D. A., 1987. Settlemet of the commercial scallop, Pe c te n fum atus (Reeve) 1855, on a rtific ia l c o lle c to rs in e a ste rn Ta sm a nia . A q ua c ulture 66:79- 95. Ro b ins- Tro e g e r, J. B. & Dre d g e , M. C . L., 1993. Se a so na l a nd d e p th c ha ra c te ristic s o f sc a llo p sp a tfa ll in a n A ustra lia n sub tro p ic a l e m b a ym e nt. J.Shallfish Re s. 12:285-290. Saucedo, P., M. Bervera, V. Perez & Wright, H. 1994. Repopulation of natural beds of pearl oysters Pinc tada mazatlanic a and Pte ria ste rna in Ba ha i d e La Pa z, So uth Ba ja C a lifo rnia , Me xic o A b strac ts o f Pro c e e ding s o f Pe arls ’94, Ho no lulu, Hawai : p: 349-350.