|Riley, Kenneth - HBOI|
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 2006
Publication Date: February 1, 2007
Citation: Weirich, C.R., Riley, K.L. 2007. Evaluation of growth and development of hatchery-reared larval black sea bass centropristis striata via image analysis [abstract]. Book of Abstracts Aquaculture America. p. 988. Technical Abstract: To improve the understanding of larval development and to refine hatchery production techniques for black sea bass Centropristis striata, digital photography and image analysis were employed to characterize growth and development of larvae from hatch through metamorphosis. Within 12 h after hatching (Day 0), approximately 40,000 black sea bass larvae were stocked into an 800-L cylindrical fiberglass tank (50 larvae/L). Larvae were reared at 24 C using established protocols until > 95% were post-metamorphic juveniles (Day 26). Samples of 10-13 larvae were collected daily and photographed using dissecting and compound microscopes equipped with digital cameras. Images were measured to the nearest 0.01 mm to determine total length (TL), standard length (SL), body depth (BD), eye diameter (ED), and head length (HL). Oil globule diameter of yolk sac larvae was measured to determine oil globule volume (OGV), and yolk length and diameter were measured to determine yolk volume (YV). Upper and lower jaw length of larvae were measured to determine mouth gape (MG) and a range of optimal prey sizes was estimated based on 30% and 50% of this value. Day TL SL BD ED HL 0 2.39 2.29 0.73 0.17 --- 4 2.84 2.68 0.46 0.25 0.53 8 3.73 3.55 0.67 0.35 0.88 12 5.20 4.90 1.10 0.48 1.56 16 7.56 6.65 1.64 0.63 2.03 20 11.09 9.33 2.32 0.98 2.97 24 14.32 11.75 3.06 1.19 3.84 Mean (± SE) OGV and YV of recently hatched larvae were 1.57 ± 0.10 µm3 and 0.20 ± 0.020 mm3, respectively. Both parameters decreased rapidly and by Day 3 endogenous food reserves were exhausted. Eye pigmentation, mouth parts, a complete digestive system, and the presence of live food organisms and algae were evident by Day 3. Swim bladder inflation was complete on Day 8, preflexion was first observed on Day 13, flexion was apparent from Day 14 to Day 19, and postflexion and the onset of metamorphosis were first observed on Day 20. Mean growth rate (as TL, SL, and MG) of larvae over the course of the rearing period was 0.48 ± 0.11, 0.38 ± 0.09, and 0.37 ± 0.11 mm/d, respectively. Predicted values for optimal prey sizes ranged from 50 to 84 µm on Day 3, 86 to 143 µm on Day 6, 167 to 278 µm on Day 9, and 323 to 538 µm on Day 12. Based on these results a suggested feeding regimen for black sea bass larvae will be presented in addition to more detailed information on growth and development.