OPTIMAL SALINITY-TEMPERATURE COMBINATIONS FOR THE EARLY LIFE STAGES OF GILTHEAD BREAM,Sparus auratus L.

High larval mortalities during rearing of gilthead bream, Sparus auratus L., led to experiments on the influence of salinity and temperature on eggs and yolk-sac larvae. Test salinities ranged from 5 to 70 ppt for eggs and from 15 to 45 ppt for larvae; experimental temperatures were 18–20°C for eggs and 18, 23 and 26°C for larvae. Spawning conditions were 18–20°C and 33–35 ppt salinity; the yolk-sac larvae were chosen from hatches obtained under similar conditions (18°C and 35 ppt salinity). For eggs the optimum survival range was found to be 30–50 ppt at 18°C and 15–60 ppt at 23°C, while that for yolk-sac larvae was 15–25 ppt at all three temperatures. Choosing normal development (no dorsal curvature) as the decisive criterion, the optimum salinity range for egg incubation was reduced to 30–40 ppt at 18°C and to 35–45 ppt at 23°C, while that for the yolk-sac stage remained 15–25 ppt at all test temperatures. Egg incubation was most successful at salinity-temperature combinations close to those during spawning, whereas salinity had to be reduced by at least 10 ppt for yolk-sac larvae.     

Salinity Effects on Early Life Stages of Southern Flounder Paralichthys lethostigma

Abstract.— In South Carolina, studies have been conducted to develop rearing techniques for southern flounder Paralichthys lethostigma a candidate for aquaculture development and stock enhancement programs. To help define environmental tolerances, a variety of salinity studies were conducted with the early life stages of this species. Eggs were buoyant at 32 ppt and sank at 29 ppt with salinities of 30–31 ppt providing varying levels of suspension in the water column. Eggs incubated at 0 and 5 ppt all died, whereas 82.5% hatched at 10 ppt but larvae died shortly thereafter. At 63 h post-fertilization, there were no differences in hatch level for eggs incubated at salinities of 15 to 35 ppt (mean hatch level 98.5%). In a 72-h study, fish 3 wk post-metamorphosis (13.7 mm TL, 50-d-old) were acclimated to seven salinities ranging from 0–30 ppt. Fish held at 0 ppt salinity exhibited a statistically (P < 0.05) lower survival (20.0%) than those exposed to 5–30 ppt salinity concentrations. No differences were detected in survival (mean 99.1%) among fish held in the higher salinities. A second study examined the tolerance of older juveniles to lower salinities. Juvenile flounder (95.2 mm TL, 220-d-old) were acclimated to 0, 1,5 and 10 ppt salinities and reared for 2 wk. Results showed that fish could tolerate salinities of 0–10 ppt (100% survival). These data indicate that salinity tolerance of southern flounder increases with age. In addition to the short duration studies, a replicated 11-mo duration tank grow-out study was conducted at mean salinity 5.4 ppt and mean temperahue 22.6 C with an all male population. Flounder grew from a mean length of 100 mm to 213 mm TL and weight from 8.9 to 104.3 g. Growth of the cultured fish approximated that observed among male flounders in the wild.     

Some effects of temperature and salinity on laboratory-reared eggs and larvae of Polydactylus sexfilis (Pisces: Polynemidae)

Effects of temperature and salinity on eggs and yolksac larvae of Polydactylus sexfilis (Cuvier and Valenciennes) were examined in laboratory experiments. Data on developmental rates as influenced by temperature are presented. Larval length at 95% yolksac absorption was maximized between 23.8 and 28.6°C. Based on the development of functional eyes and jaws, larvae were judged capable of feeding before the yolk was completely absorbed. Larvae incubated at intermediate temperatures also had larger amounts of yolk remaining when eyes and jaws were judged functional. Temperature and salinity effects on hatching success, survival at the end of the yolksac stage, and morphological abnormalities were studied in a 10 × 5 (temperature × salinity) array of treatments. In 34‰ sea water, normalized larval survival at the end of the yolksac stage was greater than 50% between temperatures of 21.9 and 28.0°C. Larval survival decreased at lower temperatures and salinities. Proportions of abnormal larvae increased at temperature and salinity extremes, and normal development was maximized between 26 and 34‰. Larvae (74 h after fertilization) were more tolerant to extreme high temperatures than were newly fertilized eggs. Upper salinity tolerance limits of 42-h larvae were greater at 26.2°C than at 23.5 or 29.2°C, and lower salinity was less tolerated at the two extreme temperatures. Based on the results, recommended temperatures and salinities for rearing P. sexfilis eggs and early larvae are 24–28°C and 26–34‰.     

Salinity tolerance of Nile tilapia fry (Oreochromis niloticus), spawned and hatched at various salinities

Fertilized eggs of the Nile tilapia (Oreochromis niloticus L.) spawned in freshwater, were removed from mouthbrooding females, 1 day post-spawning and artificially incubated at elevated salinities. At 6 days post-hatching, mean survivals of 85.5, 84.4, 82.5, 56.3, 37.9, 20.0 and 0% were recorded for broods incubated at salinities of 0, 5, 10, 15, 20, 25 and 32 ppt, respectively. Fertilized eggs exhibited a 96-h median lethal salinity (MLS-96) of 18.9 ppt, a value identical to that of 7- to 120-day-old fry and fingerlings. Fertilized eggs exhibited a higher median survival time (ST₅₀ = 978 min) than 7- to 395-day-old fry and fingerlings (ST₅₀ = 28.8–179.0 min).The salinity tolerances of fry spawned at various salinities and fry spawned in freshwater but hatched at various salinities, were determined using the median survival time (ST₅₀), mean survival time (MST) and 96 h-median lethal salinity (MLS-96) indices. For comparative purposes, fry spawned and hatched in freshwater were acclimatized to various salinities and their salinity tolerance determined. Fry salinity tolerance progressively increased with increasing salinity of spawning, hatching, or acclimatization. However, at equivalent salinity, early exposure (spawning) produced progeny of comparatively higher salinity tolerance than those spawned in freshwater and hatched at elevated salinity. Similarly, at equivalent salinity, progeny spawned in freshwater but hatched at elevated salinity exhibited higher salinity tolerance than those spawned and hatched in freshwater, then acclimatized to an elevated salinity.The utility of these methods of early salinity exposure toward the saltwater culture of tilapias is discussed.     

盐度对黄鲷胚胎发育及早期仔鱼生长的影响

The effect of salinity on embryo and early larva development of Dentex tumiforns was discussed. Floating forms of egg in different salinities, optimal salinity for embryonic development and early larva growth was studied. The results showed: 1. In immobile condition, all eggs sank at salinity of 32.0, most of egg ssuspended in the middle of water at 34.0, and all eggs floated on the surface when salinity above 36.0. 2. Eggs did not hatch out at salinity of below 10.0 or above 60.0 and the death time of egg gradually moved up with increase or decline of salinity. Eggs hatched out at salinity range of 15.0 and 50.0, including abnormal larva. There was indistinct difference in speed of embryonic development (about 36-40h) within the salinity of 15.0 and 50.0. However the salinity had a great effect on larval survival after hatching and abnormal rate. The relation between hatching rate and salinity variation showed parabola but abnormal rate showed inverted parabola. The hatching rate was 81%-86% and abnormal rate of yolk sac larva was 27%-30% in suitable salinities of 27.0-39.0. The hatching rate was 89%-91% and abnormal rate was 13%-16% in optimal salinities of 33.0-36.0. The oil ball of abnormal larva was located in the central or front position. With increased extent of salinity, spondyle of larva bended and number of larva with arrhythmia increased. 3. The optimal salinities were 30.0-35.0 based on SAI. The test with SAI showed that SAI of early larvae was 41.25-47.53 at salinities of 30.0-35.0, the yolk and oil ball of 7-8 days larva was completely absorbed with a survival rate of 88%.     

Effects of Temperature and Salinity on Weight Gain, Oxygen Consumption Rate, and Growth Efficiency in Juvenile Red-Claw Crayfish Cherax quadricarinatus

Abstract.— Weight gain and metabolic rates, as determined by oxygen consumption rates, were examined in juvenile Australian red-claw crayfish Cherax quadricarinatus exposed to different temperatures (16–32 C in 2 C increments) or salinities (0–30 ppt in 5 ppt increments). Mean weight gain, molting frequency, and survival (%) were dependent on temperature and salinity. In freshwater (0 ppt), maximal weight gain and molting frequency were observed at 28 C with maximal survival observed over the temperature range of 24–30 C. Metabolic rates in freshwater were temperature dependent (mean Q₁₀= 2.44). Maximal weight gain and molting frequency were observed at salinities of 0 and 5 ppt (28 C); however, survival was reduced at salinities ≥ 5 ppt. Metabolic rates were not salinity dependent and did not differ significantly over the salinity range from 0–20 ppt. Growth efficiencies, calculated by dividing weight gain by total metabolic energy expenditure (i.e., weight gain + metabolic rate), were highest at a temperature of 20 C (0 ppt) and at salinities of 0 and 5 ppt (28 C). These data suggest that, at higher culture temperatures, maximal weight gain of red-claw juveniles may be reduced when food resources are limited. Maximal weight gain, at optimal temperatures (28 C) with unlimited food supply, does not appear to be effected by low salinity conditions. Because of the potential commercial value of red-claw, culturists, should be aware of the relationship between environmental condition and metabolic energy requirements to ensure maximal weight gain and survival of juveniles.     

The Effects of Temperature, Age, and Acclimation to Salinity on the Survival of Farfantepenaeus paulensis Postlarvae

Abstract.— Salinity tolerance limits during the ontogenetic development of Farfantepenaeus paulensis postlarvae (PL) were determined at different temperatures. Initially, PL 10, 20, 30, 40, 60 and 80 maintained in 30 ppt (parts per thousand) salinity, 22‐25 C, were directly transferred to 15 combinations of salinity (2, 5, 10, 20 and 30 ppt) and temperature (15, 20 and 30 C) for 96 h. Irrespective of age or salinity, higher survival rates were registered at 25 C. PL 10 suffered high mortality, especially at low salinities combined with low (15 C) or high (30 C) temperatures. From PL 20 to PL 40, an increase in survival was observed in all combinations. For PL 60 and 80, tolerance to low salinity was reduced, suggesting that PL have a maximum age by which they are able to develop adaptability to low salinities. In general, the effect of temperature contributed more significantly to mortality in PL 10 and PL 30, but its influence decreased afterwards. From PL 40, salinity becomes the main factor determining mortality. In order to examine the effects of acclimation to salinity on the tolerance limits, a second set of experiments was performed with PL 5, 10, 15 and 25 acclimated to 2, 5, 10, 20 and 30 ppt, 25 C, over a 5‐d period. Postlarvae were then transferred to different salinity levels (2, 5, 10, 20 and 30 ppt) and kept for 96 h. High mortality of PL 10 occurred after direct transfer from high to intermediate/low salinity levels. Although the acclimation to salinity increased survival, it was still poor. An increase in the salinity tolerance was observed from PL 15 to 30, even with no acclimation. Results indicate that PL 10 do not have a fully developed osmoregulatory capacity to cope with low and/or abrupt changes of salinity. It is recommended that non‐acclimated PL 10 should only be released in environments with salinity at or above 20 ppt. If acclimation is carried out, PL may be released in salinities above 10 ppt. The release of PL 10 in salinities below 5 ppt may result in mortality rates of up to 70%. The best age for the release of non‐acclimated F. paulensis PL in environments with low and/ or wide fluctuations of salinity would he PL 15‐30.     

Salinity and temperature effects on productivity of a tropical calanoid copepod Pseudodiaptomus incisus

Pseudodiaptomus species are major live feeds for the early stages of economically important marine fish in hatcheries in the South China Sea. However, we know little about the combined effects of multiple environmental parameters such as salinity and temperature on copepod productivity. To address the issue, we cultured a tropical coastal copepod Pseudodiaptomus incisus in one of 24 combinations of 8 salinities (5, 10, 15, 20, 25, 30, 35 and 40 ppt) and 3 temperatures (26, 30 and 34°C). We determined development, biomass of all stages, fecundity, percentage of females with hatched eggs and 30 hr nauplii production. Overall, the biomass, fecundity and nauplii production of P. incisus were highest at the salinity of 15–20 ppt, especially at 26°C. P. incisus showed a lower performance at both lower and higher salinities. Elevated temperatures resulted in faster development, but lower biomass, fecundity and nauplii production. Especially, nauplii production was reduced by 74% at 35–40 ppt and 34°C compared to at 15–20 ppt and 26°C. Our study provides essential information for optimizing the biomass culture of P. incisus.     

Investigations of Selected Parameters for Growth of Larval and Juvenile Black Sea Bass Centropristis striata L.

Abstract.— The black sea bass Centropristis striata L. endemic to the U. S. Atlantic and Gulf of Mexico coasts is a highly sought species that commands a high price in the marketplace. Investigations were undertaken to determine the basic requirements for culture of sea bass larvae and juveniles. Adult black sea bass were captured from the wild and were found to be robust and to adapt well to captivity. Larvae were obtained by strip spawning of these adults and survived and grew at higher rates in seawater supplemented with algae (greenwater) and maintained at 22 C, than in seawater with or without supplemental algae at 18 C. Larvae were provided a diet of rotifers through 12 d post hatch (DPH) and weaned over a 3-d period to enriched Anemia replenished daily to a density of 10 individuals/mL. By 18 DPH, larvae began ingesting a formulated diet for marine finfish and were completely weaned from live feed by 25 DPH, which coincided with the onset of metamorphosis. Juveniles tolerated a range of salinity from 10–32 ppt with the highest growth rate observed at 20 ppt. Culture of larvae and juveniles on a commercial scale was successful using conditions similar to those employed in the laboratory. The findings presented here suggest the potential for commercial culture of this species in the USA.     

盐度对暗纹东方鲀胚胎发育的影响

研究了不同盐度对暗纹东方鲀胚胎发育的影响，盐度为4和8的试验组中受精卵的发育历期、孵化率及初孵仔鱼24小时的存活能力和淡水相比均无显著差异。在盐度12及以上，绝大部分受精卵死亡，仅有极少数个体孵化出膜，且全为畸形并都在24小时内死亡；发育速度随着盐度的升高而变慢。因此，暗纹东方鲀胚胎正常发育所能耐受的盐度范围是0～8。     

Effects of temperature, salinity and pH on larval growth, survival and development of the sea cucumber Holothuria spinifera Theel

For large-scale seed production of sea cucumbers through a hatchery system, it is imperative to know the effects of environmental parameters on larval rearing. Auricularia larvae (48 h post-fertilization) were obtained from induced spawning of Holothuria spinifera and used in experiments to ascertain the effects of temperature, salinity and pH on the growth and survivorship of the larvae. The larvae were reared for 12 days at temperatures of 20, 25, 28 and 32 °C; salinities of 15, 20, 25, 30, 35 and 40 ppt; and pH of 6.5, 7.0, 7.5, 7.8, 8.0, 8.5 and 9.0. The highest survivorship and growth rate and fastest development of auricularia indicated that water temperature of 28–32 °C, salinity of 35 ppt and pH of 7.8 were the most suitable conditions for rearing larvae of H. spinifera.     

Effects of temperature on hatchability, development and growth of eggs and yolksac fry of Oreochromis mossambicus (Peters) under artificial incubation

Abstract. The eggs and yolk sac fry of the mouth brooding tilapia. Oreochromis mossambicus (Peters), were artificially reared in an experimental hatchery system at different temperatures. The hatchability, embryonic development of eggs and growth of yolk sac fry were studied under controlled conditions. It was shown that the upper lethal temperature for O. mossambicus eggs was above 40°C and the lower lethal temperature between 11°C and 17°C. For yolk sac fry these values lay between 34 and 40°C and 17 and 20°C respectively. Fry survival between 24·3 and 34·0°C was near to 100% while al 20°C it was less than 60%. The somatic growth rates of fry at temperature between 20 and 34·5°C up to 10 days post hatch are presented and were found to differ significantly. At 34·6°C a negative SGR was recorded during the period 6–9 days post hatching, but, during the first 6 days, the SGR at this temperature was more than four times higher than at 20°C. At the elevated temperatures, the utilization of yolk is faster and the loss of weight observed was due to starvation. This should be taken into account when incubating under artificial rearing condition so that initiation of exogenous feeding is timed most appropriately.     

Effects of temperature, salinity, desiccation and chemical treatments on egg embryonation and hatching success of Benedenia seriolae (Monogenea: Capsalidae), a parasite of farmed Seriola spp

The effects of temperature and salinity on the embryonation period and hatching success of eggs of Benedenia seriolae were investigated. Temperature strongly influenced embryonation period; eggs first hatched 5 days after laying at 28 degrees C and 16 days after laying at 14 degrees C. The relationship between temperature and embryonation period is described by quadratic regression equations for time to first and last hatching. Hatching success was >70% for B. seriolae eggs incubated at temperatures from 14 to 28 degrees C. However, no B. seriolae eggs embryonated and hatched at 30 degrees C and <2% of eggs hatched when incubated at 24 degrees C after transfer to 30 degrees C for 48 h. Embryonation period was similar for eggs incubated in sea water at 25, 30 and 35 per thousand salinity, but increased for eggs incubated at higher or lower salinities. When incubated at salinities ranging from 25 to 45 per thousand, more than 70% of B. seriolae eggs embryonated and hatched. Hatching success was lower at 20 and 50 per thousand salinity and few or no eggs hatched at 10 and 15 per thousand. Hatching of B. seriolae eggs can be prevented by desiccation for 3 min, by immersion in water at 50 degrees C for 30 s or by treatment with 25% ethanol for 3 min.     

Toxicity of Chelated Copper to Juvenile Red Drum Sciaenops ocellatus1

Acute toxicity of chelated copper to juvenile red drum (x?= 3.1 g) was determined in a static test at 25 C and 8 ppt salinity. The 12, 24, 48, 72, and 96 h LC₅₀s were 1.90, 0.84, 0.75, 0.64, and 0.52 mg/L copper, respectively. Effects of temperature and salinity on the 96 h LC₅₀ (0.5 mg/L copper) for juvenile red drum (x?= 5.0 g) were tested at two temperatures, 25 and 30 C, and three salinities, 0.5, 8, and 30 ppt. Temperature significantly affected mortality; mortality in 0.5 and 8 ppt salinities was significantly higher at 30 C than at 25 C. An increase in salinity significantly reduced the mortality of juvenile red drum. Total mortality occurred in 0.5 ppt salinity within 48 h at 25 C and within 12 h at 30 C. Total mortality occurred in 8 ppt salinity within 72 h at 25 C and within 48 h at 30 C. No mortality occurred during 96 h in 30 ppt salinity at 25 C or 30 C.     

The effects of salinity on the fertilization rate and rearing of the Persian sturgeon (Acipenser persicus) larvae

Persian sturgeon eggs were fertilized with different levels of salinities (0.5, 2, 4, 6, 8, 10, 12?ppt), and then each group was incubated in the same salinity until hatch. The fertility (%), hatching rate as well as larvae cumulative mortality rate and abnormality (%) were measured. Our Results revealed that Persian surgeon eggs could be fertilized in the different salinity concentrations but not more than 4?ppt. Moreover, hatching rate decreased with increase in salinities more than 2 and 4?ppt, respectively, and no larvae hatched in 6?ppt salinity. According to these results, the salinity tolerance threshold for Persian sturgeon larvae hatching in brackish water is less than 4?ppt.     

Combined effects of temperature and salinity on yolk utilization in Nile tilapia (Oreochromis niloticus)

The combined effects of temperature and salinity on the yolk utilization of sac fry in Nile tilapia (Oreochromis niloticus) were investigated using central composite experimental design and response surface approach. Based on the preliminary trials, temperature was determined to range from 22 to 34°C, and salinity ranging from 2 ppt to 10 ppt. The utilization was mensurated in terms of yolk sac volume. Results showed that the linear effects of temperature and salinity on the yolk utilization was significant (P < 0.01); the quadratic effects of and the interaction between the two factors were significant (P < 0.05); temperature was more important than salinity in influencing the yolk utilization. The model equation of yolk sac volume towards temperature and salinity was established. From those high R² values, the model had excellent goodness of fit to experimental data and could be applied for predictive purpose. What with the production cost, it is suggested that the temperature/salinity combination, i.e. 28–30°C/4–6 ppt, be employed during the period of sac fry rearing, in which the yolk utilization was on average 98.6%.     

Effect of Low Salinity on Growth and Survival of Postlarvae and Juvenile Litopenaeus vannamei

The effect of low salinity on survival and growth of the Pacific white shrimp Litopenaeus vannamei was examined in the laboratory due to the interest of raising shrimp inland at low salinities. In three separate experiments, individual L. vannamei postlarvae (∼ 0.1 g) were cultured at salinities of either 0.5, 1, 1.5, 2, or 3 ppt ( N = 5 or 10/treatment) for 18 to 40 d at 30 C in individual 360-mL containers. In each experiment controls of 0 and 30 ppt were run. There was no postlarval survival at salinities < 2 ppt. Survival was significantly different ( P < 0.01) at 2 ppt (20%) compared to 30 ppt (80%). Growth was also significantly different ( P < 0.01) at 2 and 3 ppt compared to 30 ppt (416%, 475%, and 670%, respectively). A fourth experiment compared juveniles (∼ 8 g) and postlarvae (∼ 0.05 and 0.35 g). Shrimp were cultured at salinities of 0, 2, 4, and 30 ppt for 40 d at 25 C, in individual 360-mL and 6-L containers ( N = 7/treatment). There was no postlarval survival at < 2 ppt. Postlarval survival at 4 ppt (86%) was not significantly different (P > 0.05) from 30 ppt (100%). Juveniles exhibited better survival at lower salinities (100% at 2 ppt) than 0.05 and 0.35 g postlarvae (29% and 14% respectively, at 2 ppt). The effects of salinity on growth varied with sizdage. Final growth of 0.05 g postlarvae at 2 ppt (693%) was significantly less ( P < 0.01) than at 4 ppt (1085%) and 30 ppt (1064%). Growth of 0.35 g postlarvae was significantly less ( P < 0.01) for 4 ppt (175%) than for 30 ppt (264%). There was no growth data for juveniles (8 g). It appears from these experiments that the culture of L. vannamei poses risks when performed in salinities less than 2 ppt.     

Effects of Temperature and Salinity upon Larval Growth, Survival and Development in Hatchery Reared Southern Atlantic Surfclams Spisula solidissima similis

Abstract.– Parameters associated with optimum larval-rearing conditions are important in developing the culturing protocol of potential aquacultural species, and have yet to be addressed in terms of water temperature and salinity for Spisula solidissima similis , the southern Atlantic surfclam. Hatchery spawned S. s. similis larvae were reared to late pediveliger stage in five simultaneously conducted water temperature and salinity treatments. This larval growth and survival experimentation consisted of three salinity treatments (15, 25 and 30 ppt) in conjunction with a water temperature of 20 C, and two water temperature treatments (15 and 25 C) in conjunction with a salinity of 25 ppt. In the 20 C temperature treatment, significantly higher larval survival and greater growth occurred (both, P < 0.0001) as compared to the 15 C and 25 C treatments by day 22. Complete larval mortality occurred in the 20 C, 15 ppt salinity treatment by day 4. No significant differences in larval survival occurred between the 25 ppt, 20 C and 30 ppt, 20 C treatments by day 22 (P = 0.714). However, significantly greater larval growth occurred in the 25 ppt, 20 C compared to the 30 ppt, 20 C treatment (P = 0.009). The optimum rearing temperature and salinity for hatchery spawned S s. similis larvae to late pediveliger stage are 20 C and 25 ppt, respectively, within the temperatures and salinities tested.     

Light intensity effects on early life stages of black sea bass, Centropristis striata (Linnaeus 1758)

The effects of four light intensities on growth and survival of first‐feeding stage black sea bass larvae Centropristis striata were investigated in a controlled‐environment laboratory. Fertilized eggs, obtained from LHRHa‐induced spawning of captive broodstock, were stocked (72 eggs L^?1) into twenty 15 L black tanks under light intensities of 100, 500, 1000 and 1500 lx, with five replicate tanks per treatment. The photoperiod was 12L:12D, the temperature was 20°C and the salinity was 35 g L^?1. Larvae were fed rotifers Brachionus rotundiformis from day 2 post‐hatching (d 2ph) at 5–10 rotifers mL^?1. Microalgae Nannochloropis oculata and Isochrysis sp. were added (1:1) daily to maintain a density of 300 000 cells mL^?1. Hatching success and larval growth and survival from d 2ph through d 15ph were monitored. Hatching success was 28–38% under all light intensities, and notochord length at hatching ranged from 2.8 to 3.0 mm, with no significant differences among treatments. By d 15ph, growth (mg wet weight) was significantly higher in the 1000 lx (0.914) and 1500 lx treatments (0.892) than in 100 lx (0.483), and a highly significant trend (P<0.01) towards increased survival with increasing light intensities was observed, from 1.3% at 100 lx to 13.9% at 1500 lx. Higher light intensities within the range of 100–1500 lx improved growth and survival of early larval black sea bass, suggesting that even higher light intensities may improve culture performance. This is consistent with conditions in shallow, near‐shore locations where eggs and larvae are distributed in nature.     

Survival and growth of sea bass (Dicentrarchus labrax) larvae as influenced by temperature,salinity, and delayed initial feeding

The determination of the optimum time and environmental conditions for initial feeding of sea bass larvae will contribute to the feasibility of their profitable culturing. Survival and growth of larvae were increased when ambient salinity (38‰) was reduced (10‰ and 20‰). Intermediate salinity (26‰) produced consistently better growth. Although increased temperatures (18 and 21°C) improved growth rates, survival was decreased below that at ambient (15°C). Feeding of cultured sea bass larvae has commonly begun at initiation of mouth opening (4 days after hatching). At reduced salinity (13‰ and 26‰) delaying initial feeding until the fifth day resulted in survival equal to that of those fed on the first day after mouth opening. Initial feeding can be delayed 2–4 days without adversely affecting survival or growth of sea bass larvae if they are held at ambient temperature in dilute sea water.