بيولوژي توليد مثل ماهي كريشو، Saurida tambil در خليج فارس ﴿استان بوشهر﴾

چكيده انگليسي :

AbstractSynodontids are widely distributed in coastal waters of the Persian Gulf The reproductive featuresof this fish were poorly studied There are only fragmentary data on the reproductive biology ofSaurida tumbil in Hendijan region The purpose of this work was to elucidate some features of thesexual cycle fecundity nature and spawning period of this most common species of the familySynodontidae in the Persian Gulf Samples of Saurida tumbil were collected from the commercialcatches at Bushehr fishery harbor from February 2007 to February 2008 by regular monthlycollections A total of 691 specimens including 39 immature 114 males and 538 females werecollected The total length in mm as well as the total weight in g of the fish were recorded After carring out biometrical measurments the fish were dissected and gonads were removed weighted to the nearest milligram and thoroughly examined for determination of its sex andmaturity stage The gonadosomatic index was calculated as the percentage of gonad weight to thetotal body weight For histological examination pieces of the gonads were fixed in 10 formalin Then they were passed through an ascending series of ethylalcohol cleared in xylene andembedded in paraffin wax 59 c Sections of 5 7 m thick were stained with Eosin hematoxylinfor microscopic examinations The total length of mature fish ranged from 26 1 to 58 cm in femalesand from 25 5 to 53 5 cm in males The weight of mature fish ranged from 136 to 1550 g infemales and from 116 to 1125 g in males The slope line b in the length weight equation for allfish was 3 042 and for immature was 3 35 suggesting an isometric and allometric growth respectively Condition factor ranged from 0 67 to 0 79 in different months The gut contentconsisted mostly of fish species and the relative length of gut RLG was 0 44 on average suggesting a carnivorous feeding habit Amongst the 691 studied fish 187 had empty and 504 hadfull stomachs Clupeids carangids and trichiurids were the most preferred preys in the fullstomachs Monthly distribution of GSI for female and male Saurida tumbil showed that the GSIvalues have two peaks the first and the maximum was in May and the second and smaller peakwas in October The minimum GSI for the two sexes was in December The GSI of females andmales fluctuated similarly It was found that female and male Saurida tumbil reach the first sexualmaturity at 27 and 25 5 cm respectively Mean absolute and relative fecundity was 263162 and273 respectively The minimum and maximum ova diameter was 6 71 stage 1 and 875 34 stage 5 The curvilinear relationship between the fecundity and total weight of the fish wasF 2657 8 W 0 6617 The mean of the sex ratio was 1 5 M F Six sexual stages were determined forfemales as follows stage I immature virgin stage II developing stage III maturing stage IV ripe stage V spawning and stage VI spent From the virgin stage to the spawning stage theoocyte diameter increased and became full of yolk globules just before spawning Six sexual stageswere also determined for males stage I Spermatogonia stage II Primary spermatocytes stageIII Secondary spermatocytes stage IV Spermatids stage V Spermatozoa and stage VI Spent From stage I to stage V the size of germ cells became smaller and in stage V testis was fullof semen and a group of spermatozoa was oriented as an umbrella in stage VI testis was wrinkled The spawning seasons for this fish were demonstrated by the establishment of its gonadosomaticindex GSI throughout its annual reproductive cycle The maximum GSI values were recorded inMay and October This finding is in good agreement with other s findings The values of fecunditydiffered from those obtained from other regions and seasons The 1 5 sex ratio also was congruentwith other studies The histological features and GSI showed that Saurida tumbil had two spawningseasons but showed no indication of hermaphroditism Key words Aulopiformes gonadosomatic index histology Iran spawning Synodontidae

عباس زاده، اكبر

بيولوژي توليد مثل ماهي كريشو، Saurida tambil در خليج فارس ﴿استان بوشهر﴾

زيست شناسي، كيجار ماهيان، ايران