Groupers are protogynous hermaphrodite fish, which means they change sex from female to male. Sex change occurs after the fish reaches a certain size or age (Ryu et al. 2013). From data in Table 4, in each tank size of male tiger and camouflage broodstock is not always bigger than the female broodstock. Large size is male broodstock is incorrect because results of his research show that fish measuring ± 3.0 kg have become productive males even though in this population there are broodstock sizes that are much larger still are female. Based on Sayano et al. (2022) presence of males and females in grouper fish in one tank has a significant impact on its reproductive phenomena. Stimulation pheromone from male broostock effect on endocrin resulting in of gonad maturity in famales for ovulation and spawning.
Cantang and cantik hybrid grouper eggs could be produced eight times a year. Broodstock groupers spawning around new moon for four to five days. For spawning time, hybridization process carried out on second to third day. Eggs produced depend on number of needs or existing orders from customers, so that it could be estimated how many broods would be used for hybridization. Estimated number of eggs from brooders that have body weight of 4–10 kg is 400,000–700,000 eggs/fish. Temperature in August–September and January–March is lower than in other months with range temperature maximum and minimum ranges high are presented in the Fig. 3. Resulting in many tiger grouper broodstock do not produce eggs or only release a few eggs, making hybridization impossible during that season. In research Yong-Bo et al. (2013) development and hatching rate of sevenband grouper (Epinephelus septemfasciatus) rely on the salinity and temperature of the water where they spawn in Korea throughout summer. Sugama et al. (2012) noted refractory phase in spawning activity at lower water temperatures (25°C) in E. fuscoguttatus reared in RAS from Indonesia. An increase in feed intake is a strategy to compensate for high metabolic demands during thermal shift conditions (Das et al. 2021). In this research, addition of vitamin E helps protect fish body from pathogens and also promotes gonadal development, vitamin C can boost body tolerance to stress, aid in collagen formation, and prevent aberrant metabolism. Additionally, vitamin E can be employed to enhance cell membrane performance (Septian et al. 2022).
Survival rate of seeds cantik hybrid grouper was higher than cantang hybrid grouper (Fig. 4), but growth rate cantang hybrid grouper was higher than cantik hybrid grouper (Fig. 5). This is consistent with goal of hybridization, which is to increase profitability of business with fast growth in cantang grouper following its male broodstock, namely giant grouper. Cantik hybrid grouper has growth like tiger grouper, is easy to produce and is resistant to diseases like camouflage grouper (Sun et al. 2016; Anita and Dewi 2020).
Based on research in six cycles in small-scale hatchery, temperature been the smallest range was in the December 2021 to February 2022 cycle, this affects survival of grouper larvae higher than other cycle. Water parameters in for cycles in small-scale hatchery business during larval rearing such as pH, salinity and DO have the same range of values for each cycle. Quality issues of larvae and seeds in small scale hatchery also studied under conditions such as: water temperature (Watanabe et al. 1995), aeration, salinity, and light intensity (Toledo et al. 2002) affect egg, larvae and seeds development (Young-Bo et al. 2013). In small-scale hatcheries, survival rate and growth of seeds hybrid grouper are main thing in sales to increase profitability. Nurseries aim to prepare seeds with a larger size that are more resistant to environmental changes and more adaptive to marine culture treatments (Fachry et al. 2018).
Small size of grouper are vulnerable to natural conditions, so risk of death is very high if they are directly reared outdoors such as net cages or fish pond. Temperature, dissolved oxygen, salinity, and pH still in range that supports nursery of hybrid grouper seeds. Research on nursery business conducted in building semi-indoor room using partially transparent roof covered with shelter for light control, water exchange system system using recirculating aquaculture system (RAS) (Astari et al. 2023). Seeds size ± 3 cm from hatchery needs to be reared again in nursery stage to make it easier for marine culture to get grouper seeds of the right size, amount and time as desired (Dennis et al. 2020). Result of nursery cantik hybrid grouper had higher survival rate than cantang hybrid grouper, deaths often occur due to cannibalism which are caused is influenced by differences in fish size, lack of food, light intensity, and frequency of encounters between fish (Yang et al. 2015). Hybrid grouper seeds cantang growth faster than cantik (Fig. 7). Nursery business rearing for 45 days/cycle production and producing seeds cantang and cantik hybrid grouper size of from ± 3.0 cm until ± 10.9 cm and from ± 3.0 cm until ± 10.1 cm. Grouper nursery can be profitable business with price of grouper seeds follows their length size. So, the longer the seeds, the higher the price.
Business profitability analysis is concept to assess absolute profit status of a business. Profit value in hybrid grouper egg production, small scale hatchery, and nursery business is quite large for aquaculture cultivation activity unit. R/C ratio that is more than 1 means it is profitable, if it is equal to one it means break even, and if it is less than one it means a loss. Break Even Point is condition where total revenue equals total cost, meaning that business will be at breakeven point (no profit and no loss) if it is able to produce that amount (Adi et al. 2019). Profitability analysis can be used to calculate profit estimates based on asset value and investment in aquaculture business activities. Thus, results of this business profitability analysis can be used as reference for implementation model for development of an active business unit (Ariadi et al. 2019).
Business feasibility analysis is process to determine how much profit or benefit may be made from business so that it is feasible to continue. A metric of cumulative cash flow depicts all net cash flows over a certain time period. A positive value means that the inflow of cash has outweighed the outflow over that time period after the cash flows have been netted off against each other. By taking into consideration the timing of the cash flows and the time value of money, net present value (NPV) broadens the scope of the analysis. In order for management to assess a project's advantages and disadvantages at a single point in time, NPV analysis applies the time value of money to cash inflows and outflows across the course of the investment project. It expressly acknowledges that money received today (present value) is more valuable than money obtained in the future. The present value of future cash flows, discounted at the appropriate cost of capital, less the initial investment, is the definition of net present value (NPV). Measure of economic feasibility, a positive NPV shows that the present value of the net cash inflows expected during the project's life surpasses the amount of the initial investment. Investment would not be economically possible if the benefit cost ratio was less than one. In the meantime, a break-even situation would exist if benefit cost ratio equals one. Discount rate known as the IRR reduces the present value of net cash inflow to zero. As a result, a project is approved if its IRR is greater than or equal to the needed rate of return (Afero et al. 2010). Performance metric known as return on investment (ROI) is used to assess an investment's effectiveness or profitability or to compare the effectiveness of several distinct investments (Bombeo-Tuburan et al. 2001). Financial standards and profitability levels serve as indicators of the potential and viability of business ventures. When considering an activity's viability from a business perspective, investment criteria and environmental support are a couple of the factors that are taken into account. The fundamental requirement that has emerged for the deployment of marine aquaculture is the ability of the environment to support it financially and ecologically (Mukhtar 2021).
Important key variables in results of sensitivity analysis are survival rate and selling price, show the greatest influence on profitability of three business segments of hybrid grouper seed production. This can be seen from the increase in production of up to 20% in line with increase in survival rate contributing to positive net present value in egg production, small-scale hatchery and nursery business. Decrease of production and selling price in egg production, small-scale hatchery and nursery business are still economically feasible. Evaluation of management for improving survival rates in egg production, small-scale hatchery, and nursery businesses is urgently needed to gain greater economic benefits. Increase in costs such as broodstock, eggs, seeds, feeds, or labor that occurs in sensitivity analysis still shows that egg production, small-scale hatcheries, and nursery businesses are still economically feasible. Economic feasibility was also demonstrated in research (Afero et al. 2010) for grow-out business of tiger grouper and humpback grouper. Cost and production fluctuations used in the sensitivity analysis greatly affect the value of the internal rate of return (IRR). Higher IRR also indicated prospects for additional development relative to egg production, small-scale hatchery, and nursery business as well as potentially profitable investment options (Campo and Zuniga-Jara 2017).
Results of this research have provided important information about economic viability of egg production, small-scale hatchery, and nursery hybrid seeds production businesses. Maintenance management needs more attention because the survival rate is low at the change of seasons. Producers need to select high-quality seeds and proper water quality management to ensure high survival rates. In general, three business segments were profitable and mutually dependent on one another. Number of eggs production businesses was limited because one egg producer could supply many requests for eggs from several hatcheries. In this research, hatcheries had cantang hybrid grouper survival rate 5.2–15.7%, meanwhile cantik hybrid grouper 7.4–18.2%. For marketing, seeds from hatchery size of ± 3.0 cm besides being distributed to domestic nursery businesses was also exported mainly to Singapore, Malaysia and Vietnam. To meet market demand, this business has developed more than others. One nursery bought small seeds from several hatcheries, then seeds of ± 3.0 cm size was reared for 45 days produced cantang hybrids to ± 10.9 cm with survival rate of 60.2–84.5% and cantik hybrids grouper of ± 10.1 cm with survival rate 62.5–91.8%. Seeds from nursery were marketed to mariculture (net cage or fish pond) close to them. Big size seeds for long distance shipment and exports are contained by transportation cost (Ismi and Setiabudi 2021).