Investment in ma king eggs 2 sec ond a nd subsequent

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: r ed to ener gy investment in ma king eggs 2) sec ond a nd subsequent yea r s - oyster s will bec ome fema les when envir onmenta l c onditions a r e fa vor a ble for the investment of ener gy in eggs (r emember oyster food is a lga e) B a sic for mula = if its a str essful envir onment, sta y ma le; a good envir onment bec ome a fema le 3) stor ed ener gy sour c e for oyster s is glyc ogen (a c a r bohydr a te), unlike other a nima ls whic h stor e ener gy a s fa t; a good stor e of glyc ogen is essentia l for a dequa te egg pr oduc tion 4) Spa wning - c ollec t ' fa t' (well fed) oyster s; ma inta in in fr esh sea wa ter a t 18- 20 C for 4- 6 weeks; to br ing on spa wning, r a ise wa ter temper a tur e to 20 C then r a ise . 5 hr s la ter to 25 C a nd then, if nec essa r y, to 30 C a nd fluc tua te temp ba c k a nd for th a t 25 a nd 30 C until the oyster s spa wn ga metes (eggs); c a n a lso spa wn by shuc king oyster s (opening them) a nd distr ibuting ga metes by ha nd d) Gr owth of Oyster s 1) fer tiliz ed eggs - no feed nec essa r y 2) 1- 6 da ys - veliger la r va e feeding a t low level (30, 000 a lga l c ells/ml wa ter ) 3) 7- 14 da ys c ontinue feeding veliger la r va e, inc r ea sing feed c onc entr a tion to 50, 000 c ells/ml fed twic e a da y 4) 14- 21 da ys - pediveliger la r va e (eye sta ge) with inc r ea sing feed to 80, 000 c ells/ml 5) 21 da ys - spa t; r ea dy for setting on c ultc h a nd setting on ba y bottom, r a c ks, stic k & ba g, tr a y c ultur e (tha t is, for gr ow out to a dult for m tha t' s r ea dy to ea t) (r emember , some methods ha ve oyster s r a ised c ultc hless, tha t is without a piec e of shell or gr a vel to a tta c h on a nd gr ow out) 6) idea l gr owing temper a tur es - 20 C with 25 to 35 pa r ts per thousa nd sa lt; time to ma r ket: Ala ska - 4- 6 yr s; Wa sh. - 3 yr s; Or e. - 3 yr s; CA - 1. 5 yr s Definition - Xenomor phism - a n individua l wher e the body sha pe c onfor ms to the sha pe of the envir onment (oyster s a r e xenomor phic ) (the nic er sha ped oyster s br ing mor e $$) a nima lsc ie nc e 2.uc da vis.e du/a ns1/ha ndouts/a qua c ultur e .html 3/3...
View Full Document

Ask a homework question - tutors are online