Development, growth, and yolk utilization of hatchery-reared red snapper Lutjanus campechanus larvae

Abstract

The development of yolk-sac larvae of red snapper Lutjanus campechanus from endogenous utilization of nutrient sources to the development of feeding ability is described, with the aim of better understanding the high mortalities observed at first-feeding. Larvae from several spawns were reared at a salinity of 31 and a temperature of 28°C. Yolk utilization rate, changes in body parameters and the development of morphological characters were observed. Maximum standard length (L S ) and body depth were observed concurrently with yolk-sac exhaustion at 56 h postfertilization (hpf). A decrease in L S , body width and body depth was observed following yolk-sac exhaustion. Orbit pigmentation, followed by jaw articulation, were observed at 65 hpf. Substantial cranial and body cavity development occurred in the absence of visible yolk material. Complete absence of visible yolk-sac material and less than 2% of the oil globule volume at hatching were observed at the time of development of feeding ability. This indicates an absence of a transitional feeding period and the critical nature of first-feeding in this species within controlled environments. KEY WORDS: Red snapper · Larval development · Yolk utilization · Endogenous reservesResale or republication not permitted without written consent of the publisher

Dynamics of yolk sac and oil droplet utilization and behavioural aspects of swim bladder inflation in burbot, Lota lota L., larvae during the first days of life, under laboratory conditions

“…At that time, larvae had not completely used their endogenous nutritional material. The initiating of feeding by larvae even before resorption of the yolk sac was also observed in other species of fish (Urho 2002;Williams et al 2004;_ Zarski et al 2011a). The obtained results suggest that in larviculture of this species, the last moment the burbot larvae should be given exogenous food is most probably on day 10 of the development.…”

“…The absence of yolk in all larvae were observed on 13 DPH, while disappearance of the oil droplet, despite its lower initial volume, was observed 1 day later (up to 14 DPH). This suggests that fats are utilized by burbot larvae less effectively and that yolk is the first and the most important source of energy (Williams et al 2004), whereas the oil droplet probably increases the buoyancy of the larvae. The presence of yolk in some burbot larvae even by day 13 of the development seems to be relatively long compared to larvae of the Cyprinidae, in which the absence of the yolk sac was observed by about day 8 post-hatching (El-Finky and Wieser 1988;Ç alta 2000).…”

“…The spherical shape of the yolk sac of burbot larvae and a large oil droplet help the larvae to take up a vertical position in the water. This property makes burbot larvae similar to the larvae of marine fish species (von Herbing et al 1996;Williams et al 2004).…”

“…Additionally, the volume of yolk sac (VYs) and the volume of swim bladder (VSb) were measured, using the formula for the volume of an ellipsoid (e.g. Williams et al 2004):…”

“…They concerned determination of the basic rearing conditions, such as stock density (Wolnicki 2001;Kujawa et al 2002a, b), optimum temperature and photoperiod (Wolnicki et al 2002;Harzevili et al 2004) or the type of the food supplied (Harzevili et al 2003;_ Zarski et al 2009;Wocher et al 2011). Most of the studies concerning early larval development (from the moment of hatching to the moment of exogenous feeding) refer to the Salmonidae and some species of the Cyprinidae, such as the common carp, Cyprinus carpio L., the crucian carp, Carassius carassius (L.) or the chub, Leuciscus cephalus (L.) (Mark et al 1987;El-Finky and Wieser 1988;Laurila and Holopainen 1990;Ç alta 2000), as well as commercially exploited marine species (Williams et al 2004). However, studies focusing on biological aspects of early development of burbot larvae (up to the beginning of exogenous feeding) are missing.…”