research product . Other ORP type . 2015

Absolutna in relativna plodnost, masa iker ter vpliv mase iker na maso larv in zarodka pri kalifornijski postrvi (Onchorynchus mykiss) v prvi in drugi drsti

Pohar, Jurij;
Open Access Slovenian
  • Published: 10 Jul 2015
  • Publisher: Biotehniška fakulteta
  • Country: Slovenia
Abstract
Od kalifornijskih postrvi iste plemenske jate smo pridobili ikre v prvi in drugi drsti. Za vsako samico smo pri vsaki od drsti določili maso telesa (MPlm) ter absolutno plodnost (PAbs). Na podlagi teh podatkov smo izračunali relativno plodnost (PRel). Od vsake plemenke smo individualno stehtali 50 iker v fazi iker z očmi, ter tri vzorce po 50 potomcev v različnih fazah rasti. Potomce smo tehtali 11 dni po izvalitvi (T1), nato pa še 6 tednov (T2) ter 10 tednov po izvalitvi (T3). Na ta način smo dobili podatke o povprečni masi iker (MIker) ter podatke o masah potomcev pri tehtanju T1, T2 in T3 (MRib1, MRib2 in MRib3). Na podlagi teh podatkov smo s statističnim modelom parcialne regresije, ki je kot neodvisni spremenljivki vključeval relativno plodnost in povprečno maso iker, ocenili vpliv MIker na MRib1, MRib2 in MRib3. Rezultati kažejo, da se iz težjih iker izvalijo teje larve. Vpliv MIker je relativno kratek, saj parcialni regresijski koeficient MIker na MRib3 ni statistično značilen ne pri ikrah iz prve ne pri ikrah iz druge drsti. Rezultati kažejo, da je za produkcijo smiselno uporabljati tudi ikre iz prvi drsti, čeprav so majhne. Deset tednov po izvalitvi se povprečna masa rib, izvaljenih iz majhnih iker, pridobljenih pri prvi drsti, ne razlikuje bistveno od povprečne mase rib, izvaljenih iz večjih iker, pridobljenih v drugi drsti. From a certain number of females, eggs were collected during their first and second spawning. Body mass at spawning (MPlm) and absolute fecundity (PAbs) was registered for each female. On the basis of these data the relative fecundity was calculated (PRel). For each female 50 eyed eggs as well as 50 offspring at different stages of growth were individually weighted. Weightings were done 11 days (T1), 6 weeks (T2) and 10 weeks (T3) after hatching. By such procedure mean weight of the eggs (MIker) and the mean body mass of alevins attained at T1, T2 in T3 (MRib1, MRib2 and MRib3) were obtained. The statistical model of partial regression including PRel and MIkeras independent variables was used to evaluate the influence of MIker on MRib1, MRib2 and MRib3. Results indicate that from heavier eggs heavier larvaeare hatched. Nevertheless, the influence of egg weight on body mass is only short termed. Partial regression coefficient of MIker on MRib3 is not statistically significant regardless whether relation between eggs and alevins at first or second spawning is observed. According to our results it is suggested that eggs collected at first spawning should not be discarded even they appear to be too small for production. At age of 10 weeks after hatching, average siye of alevins hatched from small eggs collected at first spawning did not to essentially differ from average size of alevins hatched from large eggs collected at second spawning.
Subjects
free text keywords: akvakultura, ribe, postrvi, kalifornijska postrv, Onchorynchus mykiss, reprodukcija, ikre, larve, masa, aquaculture, fish, trouts, rainbow trout, Onchynchus mykiss, reproduction, eggs, size, larvae, mass, udc:597
Related Organizations
Communities
  • EUTOPIA Alliance
  • European Marine Science
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