Effects of development, temperature and salinity on metabolism in eggs and yolk‐sac larvae of milkfish, Chanos chanos (Forsskål)

Abstract

Oxygen uptake rates and yolk-inclusive dry weiGhts were measured during the egg and yolk-sac larval stages of milkfish, Chanos chanos (Forsskal). Oxygen uptake by eggs and yolk-sac larvae was measured to assess the effects of four salinities (20,25,30,35 ppt) at 28" C. The effects of three temperatures (23,28,33" C) on oxygen uptake by yolk-sac larvae were determined at a salinity of 35 ppt. Dry weights were measured throughout embryonic development at 28" C and the yolk-sac stage at 23.28 and 33" C.Oxygen uptake rates of eggs increased more than fivefold during embryogenesis (0.07+0.03 to 0.40 k0.03 pl Oz egg-' h-';blastula to prehatch stage). Larval oxygen uptake did not change with age but was affected by rearing temperature (0.33 i 0.08,0.44 k 0.07 and 0.63 & 0.13 p10, larva I h ' at 23, 28 and 33" C, respectively; Q,,= 1.93). Acute temperature changes from 28 to 33" C caused significant increases in oxygen uptake by embryos (Q,, = 1.69-3.58) and yolk-sac larvae (Q,,,=2.55). Salinity did not affect metabolic rates.Dry weight ofeggs incubated at 28" C decreased 13% from fertilization to hatching. Incubation temperatures from 23-33" C did not affect dry weights at hatching. Rearing temperatures significantly affected the rate of larval yolk absorption (Q," = 2.25).

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“…Additionally, start of notochord flexion Sparids mainly depends on the cultured species, size of newly hatched larvae, and culture conditions (especially rearing temperature) (Çoban, 2009b). It is well known that water temperature is the most important environmental factor affecting larval development and metamorphosis (Walsh et al, 1991;Sfakianakis et al, 2004;Saka et al, 2008). Also, the development of caudal complex begins with the formation of the hyparalia, which is closely related to the flexion of the notochord (Koumoundouros et al, 1999;Fırat et al, 2006).…”

Early development of milkfish: effects of salinity on embryonic and larval metabolism, yolk absorption and growth

“…Total oxygen consumption during embryogenesis was estimated as the areas under the curves used to describe oxygen consumption rates in relation to age. Oxygen consumption rates of milkfish yolk-sac larvae do not change with age (Walsh et al, 1991), therefore mean larval oxygen consumption rates were multiplied by age and added to embryonic oxygen consumption to calculate total oxygen consumption by larvae. These values were multiplied by an oxycalorific equivalent of 0·021 J l O 2 1 , an average value reported by Brett & Groves (1979), to calculate energetic expenditures by each of the developmental stages in each salinity.…”

“…Using eggs produced from artificially induced spawnings, Chaudhuri et al (1978) and Liao et al (1979) described milkfish embryonic and larval development. Walsh et al (1991) studied metabolism in milkfish eggs and larvae in relation to development, temperature, and salinity. These authors measured significant temperature effects on developmental rates and metabolism but detected no differences associated with salinity.…”

The effect of light intensity on early life development of common dentexDentex dentex(L. 1758) larvae

“…In Dentex dentex , the newly hatched larvae have a massive yolk sac containing the vitelline reserves and the lipid globule. The nutrition of the yolk‐sac larvae is supported by the yolk reserves (Gorodilov 1996; Mani‐Ponset, Guyot, Diaz & Connes 1996; Koumoundouros et al 1999a), and ontogeny exclusively depends on the abiotic parameters (Kinne & Kinne 1962; Ryland & Nichols 1975; Walsh, Swanson & Lee 1991; Watanabe, Lee, Ellis & Ellis 1995). The vital importance of successful feeding onset (O'Connell 1976; Fukuhara.…”