Determination of early larval feeding status of anchovy (Encraulis encrasicolus) and horse mackerel (Trachurus mediterraneus) by using the indices based on nucleic acids

Larval condition based on nucleic acids for anchovy and horse mackerel were determined. For this purpose, genoblast eggs were collected from the sea and incubated in laboratory and hatched larvae were fed with five different feeding regimes [Continuous feeding (Sb), 1 day delayed (1A), 2 days delayed (2A), 3 days delayed (3A) and starving (Ta)]. Newly hatched larvae of anchovy and horse mackerel had mean notochord lengths 3,25±0,04 and 2,27±0,04 mm, respectively. Eye pigmentation, mouth openening and first feeding occurred on the third day after hatching for both species. All anchovy larvae in Ta group dead on the sixth day while all horse mackerel larvae dead on eigth day. Survival rate of anchovy larvae in Ta group was similar to the other delayed groups. On the conrary, horse mackerel larvae in 3A group had a higher survival rate than those in Ta group (p<0,01). No Return Point (NRP) was on the first day after eye pigmentation (DAEP) for anchovy and the critical RNA/DNA ratio was 1,022±0,20. NRP in horse mackerel larvae was on 3 DAEP, the critical RNA/DNA ratio was 1,05±0,08. The highest growth rates in protein for anchovy and horse mackerel were on the 6 DAEP with 43.45% and on the 7 DAEP with 41.78%, respectively. The rate of NRP and critical level range (CLR) of sampled anchovy larvae were 9% and 19%, respectively. NRP and CLR for horse mackerel larvae were 10% and 10%, respectively. Based on the results obtained from current study, it can be concluded that anchovy and horse mackerel larvae had a high nutritional condition