Effect of different live food on survival and growth of first feeding barber goby,Elacatinus figaro (Sazima,Moura & Rosa 1997) larvae

One of the major challenges in marine fish culture is how to provide live food of adequate size and nutritional quality for first‐feeding larvae. Commonly used live food organisms, rotifers and brine shrimp, may not always be the best option. To determine the suitability of different zooplankton in the larviculture of Elacatinus figaro, three diets were tested: RE – rotifers Brachionus sp. (10 ind mL^?1)+ciliate Euplotes sp. (10 ind mL^?1), enriched with fatty acids; RC – enriched rotifers (10 ind mL^?1)+wild copepod nauplii (10 ind mL^?1); and R – enriched rotifers (20 ind mL^?1). Survival rates were estimated 10 days after hatch (DAH) for the three test groups, and growth rates were evaluated for RE and R at 10 and 20 DAH. Although survival rate was numerically higher for the RC diet (41.1±14.2%), no significant difference was detected between groups fed RE (20.5±18.1%), RC or R (32.1±16.5%). At 10 DAH, the growth rate was significantly higher in RC (5.7±0.6 mm) than in R (4.6±0.5 mm), a trend that was also observed at 20 DAH for RC (8.6±0.5 mm) and R (5.8±0.7 mm) (P<0.05). E. figaro larvae fed on ciliates did not show satisfactory results, whereas feeding copepod nauplii enhanced growth.     

Slightly salinized water enhances the growth and survival of Arapaima gigas larvae

The aim of this study was to evaluate the survival and growth of Arapaima gigas larvae reared in slightly salinized water. Pirarucu larvae (183.1 ± 41.2 mg and 3.4 ± 0.3 cm) were stocked in PVC tanks (20 L; n = 4; 40 larvae per tank) in a static system. A. gigas larvae were reared in increasing levels of salinized water (0, 1, 2, 3 and 4‰) for a period of 15 days. Fish were fed six times a day with Artemia nauplii (2,900 nauplii per larvae per meal in the beginning). The salinized water increased by at least four times the Artemia nauplii lifespan, which prolonged the time of live food supply to Arapaima larvae. Pirarucu larvae kept in freshwater presented the lowest values in weight gain, final weight and survival. Larvae reared in water with 4‰ of salinized water showed the highest final weight. Slightly salinized water enhances the growth and survival of A. gigas larvae and it can be a simple practice with low cost that can be applied in the routine of pirarucu larviculture.     

Microzooplankton as a food source for the Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis>: seasonal variation in gut contents and food availability

In this study I investigated the seasonal occurrence of microzooplankton in the gut of the Pacific oyster Crassostrea gigas. Gut contents consisted of various microzooplankton, including tintinnid ciliates, dinoflagellates (Dinophysis spp.), copepods, copepod nauplii, bivalve larvae, and rotifers. Monthly variations in the abundance of protists (tintinnids and Dinophysis spp.) in the gut contents were significantly correlated with the variation in their abundances in the surrounding seawater, whereas this relationship was not significant with metazoans (copepods, copepod nauplii, and bivalve larvae). In laboratory experiments, oysters actively fed on ciliates. When oysters fed on ciliates labeled with a stable nitrogen isotope (¹⁵N), the ¹⁵N:total N ratio of the oyster tissues was significantly higher than that for oysters under a no-food condition, suggesting that oysters assimilate nitrogen of the ciliates into their body tissues. Based on these results, I conclude that microzooplankton forms an important food source for oysters, especially when other food sources such as phytoplankton are not abundant.     

Effects of culture conditions on feeding response of larval Pacific red snapper ( Lutjanus peru, Nichols & Murphy) at first feeding

Feeding incidence or number of larvae with preys (FIC) and intensity or number of prey per larvae (FIT) at first feeding of Pacific red snapper ( Lutjanus peru) larvae was investigated under different conditions: prey type (rotifer and copepod nauplius) and density, nauplii size, light intensity, water temperature, salinity and microalgae concentration. Rotifers were not consumed at any prey density and FIC increased significantly when a high nauplii density (10 > 1, 0.1 mL^?1) and light intensity (2000 > 1000, 500, 0 lx) were supplied. In a multifactorial experiment where light intensity (2000, 2500, 3000 lx), tank colour (grey and black) and prey type (nauplii and a mixed diet: rotifers and nauplii) were tested, a significant difference was found only for light intensity and prey type with a significant interaction between these factors. FIC was significantly higher with nauplii stage I–III than IV–VI and also at 25 °C than at 28 °C. Green water (0, 0.3 × 10⁶ or 1 × 10⁶ cells mL^?1) and salinity (25, 30, 35 gL^?1) did not affect FIC. FIT was not affected by any variables tested except in the density experiment where it was significantly higher at 10 nauplii mL^?1.     

Food ingestion,consumption and selectivity of pompano,Trachinotus ovatus (Linnaeus 1758) under different rotifer densities

The growth, survival, food selection and consumption of pompano larvae under different rotifer densities as well as their colour preference during the rotifer feeding stage were examined in this study. Growth and survival of fish larvae were not significantly affected when rotifer density was between 10 and 20 mL^?1. Fish larvae grew slower at 1 and 40 rotifers mL^?1 than at 10 and 20 rotifers mL^?1, and higher fish survival was achieved when fish larvae were exposed to 10 and 20 rotifers mL^?1. The rotifer density of 1 mL^?1 not only reduced food ingestion during the early stage, but also delayed diet switch from rotifer to copepod nauplii. On 5 days post hatching (DPH), larval pompano ingested more rotifers in dark‐coloured tanks and ingested more rotifers when prey colour was green. Based on the results obtained in the present study, the culture of larval pompano larvae is recommended using dark wall tanks with a feeding density of 10–20 rotifers mL^?1 during the initial feeding stage. This study proposes a management protocol to use appropriate type and quantity of live food to feed pompano larvae in a hatchery rearing condition, which could be applicable to the culture of fish larvae in other marine fish species.     

Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

The ide Leuciscus idus (Linnaeus 1758) belongs to autochthonous, less frequent and vulnerable fish species in the frame of ichthyofauna of the Czech Republic. It was the reason for testing the possibility of captive breeding and production of fry in a controlled environment. The goal of this paper was to find the optimal transfer time of ide larvae from live food (Artemia salina nauplii) to dry starter feed providing good survival and growth. At the end of the experiment, high values of cumulative survival (in percentages) and individual weight (in milligrammes) were found for ide fry in groups D (90.6%, 178.6 mg; 15 days A. salina + 10 days starter feed), A (89.9%, 169.9 mg; A. salina only) and C (88.6%, 160.4 mg; 10 days A. salina + 15 days starter feed). Significantly lower values of the given parameters were found in group B (57.1%, 92.6 mg; 5 days A. salina + 20 days starter feed), and the lowest ones were in group E (29.8%, 75.6 mg; starter feed only). Mean values of the level of ontogenesis at the end of the experiment in fry of A–E groups were analogous to length and weight growth. Groups D, C and A consisted of juveniles only (J1, J2), and groups B and E consisted of larvae and juveniles (L4, L5, L6, J1, J2). Condition and production parameters [Fulton’s coefficient of condition (FWC), total length (TL), weight (w), specific growth rate (SGR), food conversion ratio (FCR), cumulative survival] and relationships between basic lengths TL, fork length (FL) and standard length (SL) were evaluated.     

Hormone-induced ovulation, natural spawning and larviculture of Brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839)

Mature Brazilian flounders Paralichthys orbignyanus were captured in coastal southern Brazil and their reproduction in captivity was studied. Brazilian flounder will spawn naturally in captivity when the water temperature is around 23 °C and 14 h of light is provided daily. Females were induced for ovulation and hand stripping using human chorionic gonadotropin, luteinizing hormone‐releasing hormone analogue or carp pituitary extract. There was no need to inject males, as running milt was observed during the spawning season. Fertilization and hatching rates were above 80% independent of the hormone used. Notochord length at hatching was 2.18±0.07 mm for larvae hatching from naturally spawned eggs. Larvae were reared in salt water (30–35 g L^?1) at 24 °C and under continuous illumination. Larviculture was with green water (Tetraselmis tetrathele 50 × 10⁴ cells mL^?1). Rotifers (10–20 ind mL^?1) were offered as first food 3 days after hatching and gradually replaced by Artemia nauplii (0.5–10 ind mL^?1). Larvae settled to the bottom 20 days after hatching and completed metamorphosis within a week after that. The total length for newly metamorphosed juveniles was 12.9±2.2 mm and the mean survival was 44.8%. The results demonstrate the feasibility of producing Brazilian flounder fingerlings for stock enhancement or grow‐out purposes.     

Effect of Rearing Density and Feeding Regimes on Growth and Survival of African Catfish,Heterobranchus longifilis (Valenceinnes, 1840) Larvae in a Closed Recirculating Aquaculture System

Heterobranchus longifilis larvae were reared over a 35 d period to evaluate the effects of stocking densities and feeding regimes on growth and survival. In experiment 1, larvae (12.3?±?2.1 mg) were stocked into glass aquaria at densities of 1, 2, 5, 10, 15, 20, and 25 larvae L^?1. Larvae were fed on Artemia nauplii ad libitum. Significant variations in terms of growth performance and feed utilization occurred at all levels of density treatments. Specific growth rate (SGR), body weight gain (BWG), and feed efficiency (FE) of the larvae decreased significantly as density increased. However, survival rate increased with the increase of stocking density. In experiment 2, larvae (13.4?±?1.1 mg) stocked at a density of 15 larvae L^?1, in the same conditions as experiment 1, were fed on three different regimes: Artemia nauplii; 35%?protein beef brain; and 35%?protein commercial catfish feed (CN⁺). SGR, BWG, and coefficient of variation (CV) of larvae fed on Artemia nauplii were significantly higher than those fed on beef brain and CN⁺. The survival rate of larvae fed on beef brain was significantly higher (88.40?±?9.75%) than those of Artemia (69.21?±?6.69%) and CN⁺ (40.40?±?6.22%). The results of this study suggest that the optimum stocking density is 15 larvae L^?1 and the beef brain can be used as alternative feed to Artemia in rearing H. longifilis larvae.     

Tench (<Emphasis Type="Italic">Tinca tinca</Emphasis> L.) larvae rearing under controlled conditions: density and basic supply of <Emphasis Type="Italic">Artemia</Emphasis> nauplii as the sole food

After artificial reproduction of tench, larvae must be maintained indoors, and studies on rearing conditions are needed, focussing on the reduction of labour and costs. Three experiments on larvae (5th day post-hatch) were conducted for 25 days using Artemia nauplii as the sole food in order to determine basic feeding and density conditions during the first rearing period. Tench were maintained in 25 l fibreglass tanks, supplied with an artesian water flow throughout of 0.2 l min⁻¹. Water temperature was 22.5 ± 1°C, and the photoperiod was natural. Larvae fed on a restricted amount of nauplii reached high survival rates, even with the minimum of 50 nauplii larva⁻¹ day⁻¹. This amount of food may be sufficient at least for the first 25 days of exogenous feeding if fast growth is not the priority, and high densities can be maintained with good survival rates (over 90% up to 160 larvae l⁻¹ and 77% with 320 larvae l⁻¹). When food was supplied in excess once a day, high survival rates were achieved (91–97%), without differences among the densities tested. Animals at a density of 100 l⁻¹ reached the highest length (15.57 mm) and individual weight (46.8 mg). This growth is greater than those reported in studies feeding several times a day. It could be deduced that, while live food remains available for tench, it is not necessary to feed so frequently. Considering the relationship among the initial number of animals, final survival and growth and ration supplied, the new data reported here are useful to establish suitable stocking densities under both culture and experimental conditions.     

Culture of larvae of the white mullet,Mugil curema Valenciennes

Planktonic eggs of the white mullet, Mugil curema, were collected in Biscayne Bay, Florida, and the larvae were reared in four laboratory experiments. Static rearing systems were used and copepod nauplii and copepodites were fed to larvae. Larvae grew from 2.1 mm standard length (SL) at hatching to 28.5 mm SL (35.9 mm total length) at 36 days after hatching. No significant mortalities occurred beyond 12 days after hatching. At 20 days, survival ranged from 1.2 to 23.0%. Most larval mortality occurred when larvae sank to the bottom of the rearing tanks, a phenomenon previously reported for striped mullet, Mugil cephalus. Successful culture of white mullet could have potential for meeting the demands of the live bait market for recreational fishing in south Florida.     

Increasing survival and growth in larval leopard coral grouper (Plectropomus leopardus) using intensively cultured Parvocalanus crassirostris nauplii

Leopard coral grouper, Plectropomus leopardus are a heavily exploited, high-value fish commonly found in the Asian live reef food fish trade. In past decades, many attempts at the mass culture of various grouper species have been undertaken; however, their small mouth gape at first feed has resulted in very low survival when using traditional live feeds such as rotifers. The use of wild caught or extensively cultured copepods has yielded potentially promising increases in survival and growth, but overall survival to the juvenile stage remains low, making mass culture currently impractical. The current study sought to build on past developments in grouper culture and recent advancements in copepod culture technology by observing how growth and survival were influenced by the addition of intensively cultured copepods to the early diet of P. leopardus larvae. Six tanks of larvae, three replicates per treatment, were fed either eggs and nauplii of the calanoid copepod Parvocalanus crassirostris, at a starting density of 5 mL⁻¹, and the rotifer Brachionus rotundiformis, at a starting density of 10 mL⁻¹, or were fed only B. rotundiformis, at a density of 15 mL⁻¹, starting on the evening of 2 days post-hatch (dph) and continuing until 9 dph. After this initial period, all larvae were fed the same diet of rotifers, Artemia, and dry feed until the cessation of the trial at 21 dph. Larvae fed P. crassirostris in addition to rotifers had a significantly higher survival, 9.9 versus 0.5%, than those fed only rotifers. Growth was also significantly enhanced in larvae offered copepods. Larvae only fed rotifers were, on average, 1.5 mm shorter at 21 dph than those that had been fed copepods. More rapid development and the earlier onset of flexion were also noted in the larvae that were offered copepods. The use of intensively cultured copepods, in this study, increased survival tenfold over previous studies, with P. leopardus larvae fed wild-caught copepods. The application of intensively cultured copepods to the early diet of P. leopardus, along with future research to evaluate late-stage mortality issues, may facilitate commercial production of this species.     

Comparison of Two Environmental Regimes for Culture of Australian Snapper, Pagrus auratus, Larvae in Commercial-scale Tanks

The performance of Australian snapper, Pagrus auratus, larvae from 4 to 33 days posthatch (dph) under two environmental rearing regimes was evaluated in 2000‐L commercial‐scale larval rearing tanks (N = 3 tanks/treatment). The treatments were the following: (1) a varying regime of salinity (20–35 ppt), temperature (24 C), and photoperiod (12 light [L] : 12 dark [D] to swim bladder inflation and then 18L : 06D) and (2) a constant regime of salinity (35 ppt), temperature (21 C), and photoperiod (14L : 10D). The final total length (TL) and wet and dry weights (mean ± SEM) of larvae grown in the varying regime were greater (15.6 ± 0.5 mm; 42.4 ± 3.4 mg wet weight; and 7.3 ± 0.6 mg dry weight) than those of larvae grown in the constant regime (11.1 ± 0.2 mm; 12.9 ± 0.8 mg wet weight; and 2.1 ± 0.2 mg dry weight). By 33 dph, larvae in the varying regime were fully weaned from live feeds to a formulated pellet diet and were suitable for transfer from the hatchery to a nursery facility. In contrast, larvae in the constant regime were not weaned onto a pellet diet and still required live feeds. Neither survival (Treatment 1, 14.2 ± 3.0% and Treatment 2, 13.3 ± 1.9%) nor swim bladder inflation (Treatment 1, 70.0 ± 17.3% and Treatment 2, 70.0 ± 11.5%, by 13 dph) was affected by rearing regime. The incidence of urinary calculi at 7 dph was greatest initially in the varying regime; however, by 19 dph, when larvae were 8.0 ± 0.28 mm TL, very few larvae in this treatment had urinary calculi. In contrast, many larvae in the constant regime had developed urinary calculi and this continued until the end of the experiment. The incidence of urinary calculi was not associated with larval mortality. Extrapolation of the snapper larval growth curves for the constant larval rearing regime predicts that a further 15–18 d, or approximately 1.5 times longer, will be required until these larvae attain the same size and development of larvae reared in the varying regime.     

Survival and growth of turbot larvae Scophthalmus maximus L. Reared on different food organisms with special regard to long-chain polyunsaturated fatty acids

Turbot larvae reared on rotifers (Brachionus plicatilis) and Artemia (San Francisco brand) nauplii (A) were compared with those fed on different copepod (Eurytemora affinis) stages (B). In one trial, growth and survival of larvae from hatching to day 21, their fatty acid pattern and that of their food organisms were examined. At the age of 21 days larvae of group A measured 11·1 ± 1·6 mm total length (TL) compared with 14·8 ± 1·1 mm TL for group B. From day 3 to 8 survival was 29% (A) and 38% (B). Long-chain polyunsaturated fatty acid composition of turbots resembled that of their corresponding diets. Artemia and Artemia fed larvae were lacking 22 : 6 n-3 fatty acid.In a further study, survival of larvae from day 11 to 21 fed on Artemia nauplii (C) or copepods (D) was found to be greater with the latter diet (73 versus 93%) whereas growth during this experiment was similar in both groups. Before the start of this trial they had been reared on a mixture of copepod nauplii and Brachionus. No influence on weaning success was observed. 22 : 6 n-3 fatty acid is seen to be essential for turbot larvae: elongations of fatty acids by the larvae were not found.     

Effect of Bacillus subtilis on growth development and survival of larvae Macrobrachium rosenbergii (de Man)

A feeding experiment was conducted to investigate the effect of Bacillus subtilis bacterium, on larval growth and development rate of Macrobrachium rosenbergii (de Man) during February 28 to April 8, 2005 in University Putra Malaysia hatchery. Newly hatched larvae of M. rosenbergii were reared with two dietary treatments consisting of newly hatched Artemia salina nauplii with B. subtilis (10⁸ cells ml⁻¹), and newly hatched A. salina nauplii without B. subtilis carried out in triplicate in 60‐L aquarium (50 L⁻¹). After trial, the larvae that fed B. subtilis‐treated Artemia naupli were found to have higher survival and a faster rate of metamorphosis than larvae that were fed with nontreated Artemia naupli. There were significant differences between B. subtilis‐treated Artemia naupli and nontreated Artemia diet in larval growth and development rate of metamorphosis (P < 0.05). Larval survival after 40 days was significantly greater (P < 0.05) in the B. subtilis‐treated groups (55.3 ± 1.02) compared with the nontreated groups (36.2 ± 5.02%).     

Yields of great scallop, Pecten maximus, larvae in a commercial flow-through rearing system in Norway

Survival, growth and yield of competent great scallop (Pecten maximus) larvae were investigated during a full production season in a commercial hatchery in western Norway. Broodstock were collected from natural scallop beds and 12 groups were induced to spawn during the period December 2002 to July 2003. Larvae were reared on a large scale in 36 flow-through tanks (3500 l) at 17±1 °C and continuously fed a mixture of five algal species produced in an indoor continuous-flow system. Large variations in larval performance between spawning groups and tanks were observed, but the results were as good as earlier results using the batch system and prophylactic addition of chloramphenicol. Growth from days 3–24 averaged 4.8 μm day⁻¹±0.8 (sd) and survival 22.4%±21.8 (sd). Mean yield of day 3 larvae was 7.1%±10.0 (sd) and 26.6%±25.9 (sd) for those surviving to day 24. Yield was significantly correlated to larval survival. Larval success was related to initial larval density, algal concentration and season. It was found that the best production regime had an initial larval density lower than 6 ml⁻¹ and algal concentration of less than 12 μl⁻¹ regardless of season. Seventeen tanks met these criteria and produced a mean yield of 0.5 larvae ml⁻¹ to settlement. Flow-through systems are currently regarded as the only feasible method for viable hatchery production of P. maximus larvae in Norway.     

The Scale‐up of Spotted Rose Snapper,Lutjanus guttatus,Larval Rearing at Mazatlan,Mexico

The scale‐up of spotted rose snapper, Lutjanus guttatus, larval rearing is described. Fertilized eggs (480,000) were obtained from a 1‐d harvest of a natural spawning captive broodstock acclimatized for 1 yr and 6 mo in two fiberglass tanks (18 m³). Fourteen hours after spawning, 89.6% of the collected eggs were floating, of which 96.2% were transparent with live embryos. Incubation at 25–26 C lasted 21 h, with 90.2 ± 2.1% hatching percentage of normal larvae. The percentage of viable larvae at 48 h after hatching was 79.7 ± 1.9%. Initial stocking density was 10.4 ± 1.0 larvae/L 2 days after hatching (d.p.h.). A total of 22,600 juveniles (1256 ± 170 juveniles/m³) were harvested from six 3‐m³ cylindrical fiberglass tanks. Average survival was 12.1 ± 1.1%. Final mean length and weight were 5.5 ± 0.05 cm and 2.24 ± 0.04 g, respectively. Growth expressed in total length was TL = 2.1476e^0.0543t (R² = 0.9911). Final mean biomass and condition factor were 2.8 kg/m³, 12.3% and 1.346. General length‐weight ratio was W = 0.05460 LT^2.2306.     

Iodine‐enriched rotifers and Artemia prevent goitre in Senegalese sole (Solea senegalensis) larvae reared in a recirculation system

To study the effect of dietary supplementation of iodine in Solea senegalensis, larvae were randomly distributed in six tanks. Larvae in three tanks were given rotifers and Artemia enriched with iodine in addition to Rich Advance or Super Selco from 2 days after hatch (DAH) until 31 DAH. Larvae in a second set of three tanks were fed control rotifers and Artemia, enriched only with Rich Advance or Super Selco. Samples were collected at 2, 5, 10, 15 and 31 DAH to determine dry weight, total length, myotome height and thyroid status. Larvae fed the iodine‐enriched diet had significantly higher weight at 31 DAH and higher levels of whole body iodine concentration, compared to control larvae. At 31 DAH, larvae from the control treatment showed typical goitrous thyroid follicles. Thyroid cells of larvae from this treatment appeared columnar or afollicular, with the colloid partly or completely depleted, representative of hyperplasia (goitre). The lower growth rate in fish larvae from the control treatment was possibly a consequence of the hyperplasia, and the iodine enrichment prevented Senegalese sole larvae from developing goitre. This study demonstrates the importance of iodine enrichment of live feed for fish reared in a recirculation system.     

Mass culture of fairy shrimp Streptocephalus proboscideus (Crustacea – Anostraca) and its use in larviculture of the Persian sturgeon, Acipenser persicus

This study was conducted with cysts of Streptocephalus proboscideus obtained from the University of Gent‐Belgium. The cysts were hatched in Environmental Protection Agency (EPA) medium. The nauplii were reared at the Sturgeon Research Institute using a pure culture of Scenedesmus obliquus alga supplied at a density of 5 × 10³ cell mL⁻¹ that gradually increased to 1 × 10⁴, 5 × 10⁴ and 1 × 10⁵ cell mL⁻¹ with the growth of the nauplii. The nauplii attained sexual maturity and started producing cysts in 8 days and yielded a mean cyst number of 220±40 female⁻¹ brood⁻¹ cysts. These cysts were used in the larviculture of Persian sturgeon, Acipenser persicus (Borodin). Forty‐three larvae of Persian sturgeon (mean weight: 15.4±1.1 mg; mean length: 27.1±2.7 mm) with roughly absorbed yolk sacs were stocked in three aquaria and fed S. proboscideus nauplii at 8‐h intervals. By the end of the experiment (day 5), the mean weight and length of Persian sturgeon larvae were 51.4±13.3 mg and 20.7±1.4 mm respectively.     

Visual thresholds for feeding and optimum light intensity for larval rearing of Asian seabass,Lates calcarifer (Bloch)

This study examined the retinomotor responses and prey ingestion rates of 10‐, 15‐, 20‐ and 30‐day‐old Asian seabass Lates calcarifer under different light intensities from 0 to 1000 lx to determine the visual thresholds. Subsequently, two age groups of seabass larvae were reared under light intensities of 10, 100 and 1000 lx to determine the optimum illumination in hatchery tanks. Retinomotor response was absent in 10‐day‐old larvae, but quite marked in 15‐ and 20‐day‐old seabass at 1 lx and higher. Ingestion of Artemia nauplii by 10‐day‐old larvae was almost zero at <1 lx, increased significantly at 1 lx, and was maximal at 10–100 lx. Artemia ingestion under dim light <1 lx improved with age, and older larvae took more prey in complete darkness due to the presence of rod cells (and also free neuromasts). Larvae from 13 to 26 days group had similar survival and growth at 10–1000 lx, however, from 5 to 10 days group showed similar survival rate with highest weight gain at 100 lx. Therefore, we recommend that hatchery rearing tanks be illuminated such that the larvae in the water are exposed to approximately100 lx.     

The larval rearing of the marine ornamental crab, Mithraculus forceps (A. Milne Edwards, 1875) (Decapoda: Brachyura: Majidae)

The goal of this study is to develop a larviculture protocol for Mithraculus forceps, a popular marine aquarium species. Different temperatures (25±0.5°C and 28±0.5°C), stocking densities (10, 20, 40 and 80 larvae L^?1), prey densities (newly hatched Artemia of 1, 4, 7 and 12 nauplii mL^?1) and metamorphosis to crab conditions (Systems A and B) were tested. The best survivorship and faster development were obtained when the larvae were reared at a density of 40 larvae L^?1 for 7 days post hatching (DPH) in System A, at 28°C and fed with 7 mL^?1 of newly hatched Artemia nauplii. After 7 DPH all the megalopa were moved to System B and the same temperature and prey density were maintained. At the end of the experiment, 12 DPH, survivorship of 74.1±4.8% was obtained.