Survival Activity Index Research Articles

Benchmarking of early ontogeny parameters as predictors of the first-feeding larvae vitality in spotted rose snapper Lutjanus guttatus

A common problem in marine fish hatcheries is the lack of functional embryonic parameters reliably predicting favorable larval outcomes. Embryos characterized as high-quality by typical assessment methods frequently result in weak larvae with high mortality during the endo-exotrophic transition. Thus, because there is no universal consensus on what parameters are most associated with successful larval survivability, this study aims to determine the most reliable, practical, and real-time predictor of vitality at the earliest developmental stage for first-feeding larvae of L. guttatus. From 18 mass volitional spawnings, the reproductive performance and quality of embryos and larvae were assessed by following quality parameters: total fecundity per spawning, percentage of floating eggs, fertilization rate, blastomere morphology score (at 8–32 cell stages), egg and oil globule volumes, coefficient of variation of eggs and oil globule diameters, percentage of poly-globular eggs, oil globule-to-egg volume percentage, morphological appearance and survival rates at 24 (hatching), 48 and 72 h post-spawning, larvae transition rate, and survival activity index (SAI). SAI was used as a larval vitality benchmark to determine the predictive capacity of the abovementioned parameters. Our results show that blastomere morphology score was the only parameter positively correlated with SAI. However, when examining each component of blastomere morphology to SAI prediction, only the presence of cell inclusions, but not size, symmetry, margins, or adhesions of blastomeres, predict the SAI. This reveals that embryos with defective blastomeres can develop into normal-appearing larvae but are weak to starvation. Therefore, cell inclusions are the best real-time, early, reliable, and functional predictor of first-feeding larvae vitality in L. guttatus.

Some Hatchery Parameters of Three Species of Groupers: Tiger Grouper (Epinephelus fuscoguttatus), Humpback Grouper (Cromileptes altivelis), and Leopard Coral Grouper (Plectropomus leopardus)

Three species of groupers, including tiger grouper (Epinephelus fuscoguttatus), humpback grouper (Cromileptes altivelis), and leopard coral grouper (Plectropomus leopardus), have been successfully cultivated. However, the constraints on larviculture that have been described still arise in the hatchery. This study compares several hatchery parameters in these three grouper species representing three different genera (Epinephelus, Cromileptes, and Plectropomus). The egg incubation and larval rearing were carried out in a concrete tank (3 x 3 x 1.2 m3) filled with 6-7 m3 seawater. Eggs were stocked with a density of 100,000 eggs/tank. The grouper larvae were reared until they became juvenile. The eggs were incubated until they were hatched in the same container and media as larval rearing. Larvae were reared until 60 dah (days after hatching), and data were taken from the rearing for three cycle's larval culture. Management of grouper larval rearing follows the Good Fish Hatchery Method (Cara Pembenihan Ikan yang Baik/CPIB) based on Indonesian National Standard (Standar Nasional Indonesia/SNI). The experimental parameters were egg diameter, hatching rate, larvae mouth opening width, survival activity index (SAI), larvae development, and total body length growth. The several hatchery parameters in three grouper fish species are significantly different. The tiger grouper has the best larval performance.

Maintenance and spawning on yellowfin tuna broodstock reared in floating net cage

Yellowfin tuna (Thunnus albacares) is one of the fish species that have important economic value which is expected to become one of foreign exchange that can give solution to national economy. Hatchery technology of yellowfin tuna performed at the Research Institute for Mariculture and Fisheries Extension Gondol has been successfully spawned. However, the quality and quantity of eggs produced is still not optimal. The purpose of this study was to determine the performance of spawning on yellowfin tuna broodstock reared in floating net. This research was conducted in cage with a diameter of 48.8 m with a depth of 8 m, filled 90 fishes yellow fin tuna with weights ranging between 50-70 kg per fish. Feed given is: fresh fish, squid and added vitamin C and vitamin E. The study was conducted for 11 months from January to November 2017.The results showed that the yellowfin tuna could spawn monthly. The highest spawning frequency occurred in July at 17 times. The highest total number of eggs harvested was 8,740,350 in October. Hatching rate between 50-92%. Survival activity index (SAI) is 1.8-3.5%. Survival rate of yellow fin tuna during maintenance reached 92.2%.

Performance of yellowfin tuna spawning (Thunnus albacares) in floating net cage

Yellowfin tuna (Thunnus albacares) is an important export commodity in Indonesia. This tuna has an important economic value, so it becomes one of the foreign exchange that can provide solutions to the national economy. Yellowfin tuna hatchery technology that was carried out at the Research Institute for Mariculture and Fisheries Extension, with the management of broodstock maintenance in floating net cages has successfully spawned. However, the quality and quantity of eggs produced are still not optimal. This research was conducted in floating net cage with a diameter of 48.8 m with a depth of 8 meters, filled with 30 fishes of yellowfin tuna with body weights ranging from 60-80 kg per fish. Feed given is: fresh fish, squid and added vitamin C and vitamin E. The parameters observed were : spawning frequency, number of eggs produced, hatching rate, egg diameter, diameter of oil globule and the survival activity index value of newly hatched larvae (SAI). As supporting data, water quality observations were carried out which included: temperature, salinity, and water brightness on the floating net cage. This research was conducted for 10 months, from January to October 2019. Data analysis was carried out in discriptively. The results showed that yellowfin tuna reared in floating net cage can spawn well. Spawning occurs every month. The highest spawning frequency in October is 20 times spawning. While the highest total number of eggs successfully harvested was 11,030,000 eggs in August. Hatching rate between 70.5-92.2%. The survival activity index of newly hatched larvae (SAI) is 2.4-3.7

Combined Effects of Temperature and Salinity on Hatching and Larval Survival of Commercially Important Tropical Sea urchin, Tripneustes gratilla (Linnaeus, 1758)

The combined effects of temperature and salinity on percent hatching, normal larval rate at hatching, and survival of fasting larvae after hatching (survival activity index; SAI) of the commercial species of collector sea urchin, Tripneustes gratilla were investigated in a captive laboratory condition. The study was conducted by setting different levels of temperatures (24°C to 36°C) and salinities (38‰ to 23‰). Within the range of temperature from 24 to 36°C and at 32‰ salinity, hatching and normal larval rates, and SAI values were highest at 24 and 27°C. The highest hatching and normal larval rates were found at 35 and 38‰ within the salinity range of 23-38‰; however, SAI value was the highest at 26‰. The results of the experiments in each level of temperature (24, 27 and 30°C) with each salinity (32, 35 and 38‰) indicated interactive effects of temperature and salinity, and within the experimental protocols of 24°C at 38‰ gave an optimal combination for highest hatching and survival of T. gratilla. The findings obtained from the present research would not only be immensely helpful towards the understanding of the suitable temperature-salinity interactions but also facilitate the development of captive breeding, larval raising and mass seed production of this high-valued sea urchin for commercial aquaculture.

Combined effects of temperature and light intensity on the fry viability of Ussuri catfish Pseudobagrus ussuriensis

The combined effects of temperature and light intensity on the viability of Ussuri catfish, Pseudobagrus ussuriensis, were evaluated using a central composite orthogonal quadratic design and the response surface methodology. The optimum experimental combination was also determined. The linear and quadratic effects of temperature had a significant effect on viability (P < 0.01). The linear effect of light intensity was not significant (P > 0.05) but the quadratic effect had a significant effect on the fry survival rate (P < 0.01). The interactions between temperature and light intensity on fry viability were not significant (P > 0.05). A model equation of the survival activity index (SAI) of temperature and light intensity was established, with r2, Adjusted r2 and Predictive r2 values as high as 0.9832, 0.9665 and 0.898, respectively. By applying the optimisation technique, the optimum conditions for viability were 26 ℃ and a light intensity of 1000 lx, at which the SAI was 9.53 and the desirability value was as high as 0.948.

Antarctic krill (Euphausia superba ) meal in the diets improved the reproductive performance of tongue sole (Cynoglossus semilaevis ) broodstock

A three-month feeding trial was conducted to investigate the effects of dietary krill meal on the reproductive performance of tongue sole broodstock. Three diets were formulated to contain different levels of krill meal, 0 (Diet K-0), 10 (K-100) and 200 (K-200) g kg–1 dry matter, replacing the corresponding contents of protein and lipid from fishmeal and fish oil. Each diet was assigned to triplicate tanks. Compared with K-0, both K-100 and K-200 increased the egg properties such as buoyant eggs rate, egg diameter, oil droplet diameter and SOD activity of the fertilized egg. However, the maturation rate, serum estradiol content, the relative fecundity and hatching rate were improved only by K-100. The krill meal supplementation increased the concentrations of astaxanthin and n-3 fatty acids in eggs, but decreased the n-6 fatty acid concentrations. Both K-100 and K-200 increased the survival activity index, but the larval deformity rate was decreased only by K-100. At 15 DPH, the larval length and the digestive enzyme activities were significantly higher in group K-200 compared with groups K-0 and K-100. In conclusion, dietary supplementation of krill meal, at the level of 100 or 200 g kg–1 dry matter in exchange of fishmeal and fish oil had the considerable positive effects on C. semilaevis reproduction.

Live prey enrichment and artificial microdiets for larviculture of Atlantic red porgy Pagrus pagrus

In the first experiment the effects of rotifer enrichment and feeding frequency on larval performance of red porgy Pagrus pagrus were studied. Larvae (2 days post-hatching=2dph) were fed s-type rotifers (∼20 rotifers/mL) enriched with one of the four different treatment media: Rotifer Diet (microalgae Nannochloropsis oculata and Tetraselmis chuii), DHA Protein Selco, Algamac 3000 (Schizochytrium sp.) and Algamac+ARA (arachidonic acid). Larvae were fed daily at full ration or twice daily at half ration. Larval growth and survival (mean=22.8%) were satisfactory through 16dph under all treatments; however, resistance to hyposaline challenge (Survival Activity Index=SAI) was positively correlated (P<0.01) with DHA concentration of rotifers, and SAI appeared highest in the Algamac+ARA treatment. In the second experiment the effects of Artemia enrichment on larval performance were compared from 18dph through pre-metamorphosis (33dph). Larvae were fed Artemia (0.5–3.0/mL) enriched with two different media Algamac 3000 and DC DHA Selco, or unenriched Artemia (control). Both media improved DHA levels in Artemia and growth and survival (36.7–54.6%) of larvae, while larvae fed unenriched Artemia showed poor growth and survival (5.2%). In the third experiment a University of North Carolina Wilmington microbound diet (MBD) and two commercial microdiets (Gemma Micro and Otohime) were evaluated. The MBD contained different protein sources (i.e., menhaden, squid and krill meal, soy protein concentrate) and attractants. Beginning 16dph, live feeds and microdiets were co-fed to three treatment groups of larvae: (1) Gemma, (2) MBD, and (3) Otohime. Larval performance on the UNCW-MBD was comparable to the commercial microdiets, with no significant differences in larval survival, DHA, or total n-3 PUFA content through 32dph. Results delineate more effective rearing protocols for larviculture of Atlantic red porgy juveniles.

Effect of temperature and salinity on hatching and larval survival of yellowfin tuna Thunnus albacares

Effects of temperature and salinity on hatching rate and normal larval rate at hatching, and survival of fasting larvae after hatching (survival activity index; SAI) were investigated using spontaneously spawned eggs of captive yellowfin tuna (Thunnus albacares, YFT). Within the range of experimental temperatures, 23–35 °C, at 32 psu salinity, hatching and normal larval rates and SAI were highest at 23 and 26 °C. In the experiment exploring the most suitable salinity within the range 23–38 psu, 35 and 38 psu gave the highest hatching rate and normal larval rate; however, SAI was highest at 26 psu. The results of multi-factor experiments in each temperature (23, 26, and 29 °C) with each salinity (32, 35, and 38 psu) indicated interactive effects of temperature and salinity on the three indices and within the experimental ranges gave an optimal combination of 23 °C and 38 psu for YFT hatching and survival.

Effects of Different Dietary Lipid Sources on Spawning Performance, Egg and Larval Quality, and Egg Fatty Acid Composition in Tongue Sole Cynoglossus semilaevis

A 60-day feeding experiment was conducted to investigate the effects of dietary lipid sources on reproduction of Cynoglossus semilaevis. Experimental diets were formulated with similar proximate compositions but different lipid sources (6.5%): fish oil (FO), soybean oil (SO) and olive oil (OO). The results showed that the relative fecundity in group FO and OO was significantly higher than that in group SO. Group OO showed a significantly higher buoyant egg rate than group FO and SO. The hatching rate and larval survival rate at 7 days post hatching were the highest in group FO, followed by group OO, and group SO recorded the lowest values. Group FO showed significantly higher egg diameter and larval survival activity index (SAI) and significantly lower larval deformity rate compared to group SO and OO. Fatty acid compositions of eggs reflected closely those of the diets. These results showed that the olive oil supplement in diets for tongue sole positively influenced the broodstock fecundity and buoyant egg rate though fish oil resulted in the highest hatching rate and best larval quality among the tested oils. The dietary soybean oil supplement reduced the spawning performance, and egg and larval quality.

Ontogenesis from embryo to juvenile and salinity tolerance of Japanese devil stinger Inimicus japonicus during early life stage.

Embryonic development and morphological characteristics of Japanese devil stinger Inimicus japonicus during early life stage were investigated. Larvae were hatched out 50 h after fertilization at temperature 21°C. Total length of the newly hatched larva was 4.03 mm, the mouth of the larva opened at 3 days after hatching (DAH), and the yolk sac of the larva disappeared at 5 DAH. After hatching, the pectoral fin first developed, then the tail fin, dorsal fin, anal fin and pelvic fin continuously developed, and all fins formed completely at 15 DAH. The metamorphosis was complete at 25 DAH, and the body color and habit of the metamorphosed individuals were different from the larvae. At 30 DAH, the morphology and habit of the juveniles were the same to adults. In order to determine the suitable salinity for larviculture of I. japonicus, salinity tolerance at different early developmental stages was compared in terms of the survival activity index (SAI) and mean survival time (MST). The results indicated that salinity tolerance varied with development stages. The optimum salinity range for newly hatched larvae was 10–25‰. Larvae showed low tolerance to low salinity (5‰) before the mouth opened, and the suitable salinities for the larvae with open mouth, yolk-sac larvae, post yolk-sac larvae were 10–15‰. The flexion larvae showed a wider salinity tolerance with range of 5–20‰. After metamorphosis, the juveniles showed a preferable adaptability of salinities of 15–20‰. The SAI and MST of individuals at various stages under different salinity conditions were positively correlated.

Study on salinity tolerance and oxygen consumption of silver pomfret(Pampus argenteus)larvae

The salinity tolerance and oxygen consumption of Pampus argenteus larvae(2 days after hatching and 4 days after hatching)were investigated at salinities of 5,10,20,30,40,50,55.Mortality,mean death time(MDT),median death time(DT50),median lethal salinity-48 h(MLS-48),and survival activity index(SAI)were employed as indices of salinity tolerance,and individual oxygen consumption was detected by respirometer.The results showed that lower(5)and higher(above 50)salinities were detrimental to P.argenteus.MLS-48 for 2-day-old larvae and 4-day-old larvae ranged from 8.15 to 24.90 and 15.54 to 34.97,respectively.DT50 and MDT of 2-day-old larvae in 10-30 environment were significantly higher than other salinities,while DT50 and MDT of 4-day-old larvae were higher in 10-40.SAI of 2-day-old larvae in 10 and 20 environment were significantly higher than other salinities,while the better value of SAI in 4-day-old larvae was in 20-30,and salinity of 20 was the best one for both kinds of larvae.From the results of individual oxygen consumption,for larvae among the suitable salinity ranges(10-30),there was no significant difference between salinities,but higher salinities caused higher oxygen consumptions of larvae.The results indicated that the optimum salinity range of P.argenteus was 15.54-24.90,and higher salinity can cause an increase of oxygen consumption in P.argenteus larvae,but there was no significant effect among tolerant salinity range.

Spawning Performance of Striped Knifejaw, Oplegnathus fasciatus Fed Graded Levels of Ascorbyl-2-monophosphate Mg2+ as Vitamin C Source

This study aimed to improve spawning performance of striped knifejaw using ascorbyl-2-monophosphate Mg salt (APM) as a dietary ascorbic acid (AsA) source. Five experimental diets, a control diet 1 without APM and four test diets 2-5 with 500, 1,000, 3,000 and 6,000 mg AsA/kg diet in an equivalent basis of APM, respectively, were prepared using a semi purified fish meal basal diet. Each diet was fed to duplicate broodfish groups consisting of 4 females and 2 males, having mean body weight of 587 and 595 g, respectively, once a day for 21 weeks, from April 2006. Dietary APM promoted earlier onset of spawning and induced a tendency of improving egg quality; diet 2 had higher tendencies in egg production, buoyancy, hatching rate and larval survival activity index. Dietary APM significantly correlated to AsA levels in eggs. Groups fed diets 4 and 5 tended to induce higher abnormal larvae than groups fed diets 1-3. These results revealed that the broodfish of striped knifejaw effectively utilized APM as a dietary AsA source and promoted the early onset of spawning and performance; but high dietary APM might cause ill effects on egg quality.

Evaluation of larval quality of viviparous scorpionfish Sebastiscus marmoratus

The aim of this study was to develop an acute test for larval quality in the viviparous scorpionfish Sebastiscus marmoratus. Rearing experiments until day 13 post parturition were conducted to investigate the survival of larvae for 13 different batches, and tolerance to starvation of larvae was examined and expressed by the survival activity index (SAI). The morphological characters, enzyme activity, and swimming behavior of larvae on day 0 and 1 were also observed, followed by the correlation analysis between SAI. Larvae with high SAI (≥26) showed significantly higher survival on day 13 than larvae with low SAI, which confirmed that SAI is a reliable index that can be used to evaluate larval quality, similar to the former findings. The esterase activity (r=−0.713, P<0.01), swim frequency (r=−0.735, P<0.01) and swimming speed (r=−0.588, P<0.05) of larvae on day 0 were significantly and negatively correlated with SAI. It was concluded that enzyme activity and behavioral characters of larvae just after parturition can be a real-time index for evaluating the larval quality of this species.

A practical broodstock diet for the mangrove red snapper, Lutjanus argentimaculatus

A practical broodstock diet (39% protein, 8.6% lipid) was formulated for the mangrove red snapper as part of a project to ensure consistent production of good quality eggs and larvae through broodstock nutrition. Reproductive performance of mangrove red snapper broodstock fed practical diet ( n=14 females) was enhanced in comparison to those fed raw fish ( n=12 females). Broodstock fed practical diet had total egg production of 82.34 million from 68 spawns for two spawning seasons while broodstock fed raw fish produced 77.64 million eggs from 66 spawns. Mean percent of egg viability, hatching rates and percent of normal larvae did not vary between the two groups. However, broodstock fed the practical diet had higher mean cumulative survival rate of eggs to normal larvae (40.4%) than that of broodstock fed raw fish (35.2%). Also, survival activity index (4.08) of broodstock fed practical diet was higher than that of broodstock fed raw fish (2.97). The results clearly indicate the improvement of reproductive performance of mangrove red snapper fed practical diet. Further studies should focus on the specific nutrients that can ensure consistent production of high quality eggs and larvae of the mangrove red snapper to support its aquaculture.

Advanced broodstock diets for the mangrove red snapper and a potential importance of arachidonic acid in eggs and fry

Mangrove red snapper fed advanced broodstock diets containing squid meal and squid oil exhibited higher hatching rates, cumulative survival and survival activity index than those fed a basal diet or a basal diet supplemented with mixture of antioxidants. On the other hand, fatty acid analyses of ovaries and fry of wild fish and eggs and larvae of broodstock fed raw fish revealed high arachidonic acid (ARA) and docosahexaenoic acid (DHA) levels and relatively lower eicosapentaenoic acid (EPA) levels consequently showing high ARA/EPA and DHA/EPA ratios compared to cold water species. This suggests that ARA may be nutritionally more important for egg and larval development and survival in tropical marine fish and its supplementation in broodstock diets may enhance reproductive performance of mangrove red snapper.