Showing papers in "Reviews in Aquaculture in 2017"

The utilization and mode of action of organic acids in the feeds of cultured aquatic animals

Abstract: The use of antibiotics in the feeds of cultured aquatic animals to mitigate infectious diseases or to boost growth performance is commonly practised. In recent years, the prophylactic use of antibiotics has been criticized which eventually led to their ban in animal production by many countries. In view of the current restrictions on antibiotic use, there is a critical need to evaluate alternatives. One potential substitute for antibiotic growth promoters in aquafeeds is organic acids and/or their respective salts. The use of dietary organic acids in the culture of aquatic animals has been the focus of much research and commercial interest recently. This review provides a comprehensive compilation of the current knowledge on the use of organic acids in aquafeeds, with emphasis on its impacts on growth, nutrient utilization, mineral availability, gut microbiota and disease resistance. Many studies have reported that some organic acids can significantly enhance the growth performance and health status of fish. Contradictory results have also been reported, which seems to depend on the aquatic animal species, type and concentrations of organic acids and the culture conditions used. Recent research indicating the beneficial impact of dietary organic acids on shrimp growth and health is highlighted. Possible mechanisms of action of these functional feed additives are discussed. Strategies for enhancing the effectiveness of dietary organic acids are given. This review aims to contribute to the sustainability of global aquaculture production by providing a viable alternative to harmful antibiotics, thereby meeting the growing consumer demand for antibiotic-free seafood products.

Coping styles in farmed fish: consequences for aquaculture

Abstract: Individual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies have demonstrated links to performance traits, health and disease susceptibility and welfare. This study will review (i) the main behavioural, neuroendocrine, cognitive and emotional differences between reactive and proactive coping styles in farmed fish; (ii) the methodological approaches used to identify coping styles in farmed fish, including individual (group) mass-screening tests; and (iii) how knowledge on coping styles may contribute to improved sustainability of the aquaculture industry, including welfare and performance of farmed fish. Moreover, we will suggest areas for future research, where genetic basis (heritability/epigenetic) of coping styles, and the neuroendocrine mechanisms behind consistent as well as flexible behavioural patterns are pinpointed as central themes. In addition, the ontogeny of coping styles and the influence of age, social context and environmental change in coping styles will also be discussed.

Application of machine vision systems in aquaculture with emphasis on fish: state-of-the-art and key issues

Abstract: Demands of aquatic products are increasing dramatically during past decades. Also quality assurance has gradually received more attention by both producers and consumers. Thus, fish producers are exploring all possible approaches for improving the productivity and profitability. Monitoring of fish state and behaviour during cultivation may help to improve profitability for producers and also reduce the threat of severe loss because of disease and stress incidents. It is necessary to evaluate and measure quality of fish products in accurate, fast and objective way for meeting the different demands of the fish-processing industry after harvesting. Traditional methods are usually time-consuming, expensive, laborious and invasive. Using rapid, inexpensive and noninvasive methods is therefore important and desirable. Optical sensors and machine vision system provide the possibility of developing faster, cheaper and noninvasive methods for in situ and after harvesting monitoring of quality in aquaculture. This review describes the most recent technologies and the suitability of different optical sensors for the fish farming management and also assessment, measurement and prediction of fish products quality. Two major areas of optical sensors applications in aquaculture are discussed in this review: (i) preharvesting and during cultivation; and (ii) post-harvesting. Finally, accuracy and uncertainty of optical sensors applications in aquaculture are discussed. This review showed that MVSs and optical sensors have found real-world application based on tremendous possibility offered by digital camera development and increasing the speed of computer-based processing; however, still new algorithms, methods and re-engineered sensors need to be developed to meet real-world requirements.

A review of carotenoid utilisation and function in crustacean aquaculture

Abstract: Crustaceans are cultured extensively around the world in intensive farming systems. High-performance formulated feeds have been developed for crustacean aquaculture, which are often supplemented with a number of natural and synthetic carotenoid sources. Studies over a number of years have consistently shown that dietary carotenoid supplementation is beneficial for crustacean aquaculture across a range of commercially relevant parameters. Most obvious is the effect on pigmentation, where carotenoid inclusion levels in feeds and duration of feeding diets with carotenoids have been optimised across many species to improve product colour, and subsequently quality and price. However, beneficial effects of carotenoid inclusion have increasingly been demonstrated on other parameters. This review updates the recent progress in our understanding of dietary carotenoid utilisation and storage, and the combined effects of diet, genetics and environment on crustacean pigmentation. In addition, the range of other physiological benefits this class of molecules brings to these animals is summarised. These include improvements in survival, growth, reproductive capacity, disease resistance and stress resistance.

Physiological change and nutritional requirement of Pacific white shrimp Litopenaeus vannamei at low salinity

Abstract: The Pacific white shrimp Litopenaeus vannamei is a euryhaline species with optimal salinity of 20–25 practical salinity unit (psu) for growth and survival, but has been cultured in inland water with salinity <5 psu worldwide. In the past decade, much research progress has been made on the physiological and nutritional requirements of white shrimp at low salinity. This study reviews the recent findings in the aspects of growth, survival, energy metabolism, stress resistance and immunity of white shrimp at low salinity and synthesizes recent research outcomes in nutritional requirements in an attempt to improve the shrimp performance in aquaculture at low salinity. The white shrimp at low salinity usually show slow growth, low immunity, high susceptibility to pathogens and high energy demand. The diet containing 30–36% protein, 15–20% carbohydrate and supplementations of potassium, sodium, vitamin E and C, free amino acids (glycine, alanine, proline and taurine), antioxidants and probiotics can improve shrimp growth and immunity at low salinity. The white shrimp has demonstrated the ability to synthesize DHA and EPA from LNA at low ambient salinity, but further studies are needed to further confirm this finding. Future research should focus on the understanding of physiological mechanism and adaptation associated with salinity change and nutritional manipulation. The specific dietary requirements of essential fatty acids, essential amino acids, vitamins and minerals and the nutrition-mediated immune response also warrant further study on shrimp at low salinity.

Microbial metagenomics in aquaculture: a potential tool for a deeper insight into the activity

Abstract: The use and study of microbes in aquaculture has become a common practice in the last decade. Metagenomics is a relative recent genomics subdiscipline that has emerged as a promising scientific tool to analyse the complex genomes contained within microbial communities. However, despite the potential of metagenomics, its use is not yet common in some agro-industrial disciplines such as aquaculture. In this review, we analyse some of the potential uses of metagenomics in aquaculture to highlight the microbial diversity and dynamics of the culture systems. This review addresses some potential uses of metagenomics in the study of microbial diversity, microbial roles in microcosms, antibiotic resistance genes, novel and potential pathogens, microbial communities forming bioflocs, probiotics and other applications.

Ocean acidification and marine aquaculture in North America: potential impacts and mitigation strategies

Abstract: Shifting environmental conditions resulting from anthropogenic climate change have recently garnered much attention in the aquaculture industry; however, ocean acidification has received relatively little attention. Here, we provide an overview of ocean acidification in the context of North American aquaculture with respect to potential impacts and mitigation strategies. North American shellfish farms should make ocean acidification an immediate priority, as shellfish and other calcifying organisms are of highest concern in an increasingly acidifying ocean and negative effects have already been felt on the Pacific coast. While implications for various finfish have been documented, our current understanding of how acidification will impact North American finfish aquaculture is limited and requires more research. Although likely to benefit from increases in seawater CO2, some seaweeds may also be at risk under more acidic conditions, particularly calcifying species, as well as non-calcifying ones residing in areas where CO2 is not the primary driver of acidification. Strategies to mitigate and adapt to the effects of acidification exist on the regional scale and can aid in identifying areas of concern, detecting changes in seawater carbonate chemistry early enough to avoid catastrophic outcomes, and adapting to long-term shifts in oceanic pH. Ultimately, ocean acidification has already imposed negative impacts on the aquaculture industry, but can be addressed with sufficient monitoring and the establishment of regional mitigation plans.

Coral propagation: a review of techniques for ornamental trade and reef restoration

Abstract: Aquaculture of coral offers an alternative to wild harvest for the ornamental trade and shows considerable promise for restoring reefs and preserving biodiversity. Here, we compare advantages and disadvantages of asexually derived fragments versus sexually derived propagules and in situ versus ex situ nursery phases for the ornamental trade and reef restoration. Asexual propagules, sourced from a donor coral colony that is cut into smaller parts and attached to artificial substrate, are most commonly used. The most suitable corals are typically branching species, although fragments from species with other growth forms can be successful, albeit slower growing. Sexually derived propagules are collected from the wild or from colonies in aquaria during spawning, with an artificial substrate provided for settlement. The timing of spawning is known for many broadcast spawning corals, but opportunities for collection of gametes are generally limited to only once or a few times per year. Brooding species with multiple periods of larval release provide better options for culture of sexually derived propagules. Propagation techniques have developed considerably over the past 20 years, yielding faster growth rates, reduced mortality and reduced detachment from substrates. Simple and cost–effective propagation techniques can be used to restore denuded reefs, preserve endangered species, provide live corals to the international ornamental trade, enable livelihood diversification for coastal communities and provide experimental materials for marine research. This review provides a comprehensive synthesis of recent developments in aquaculture propagation techniques for the purpose of ornamental trade and coral reef restoration, including asexual and sexual propagation, nursery and transplantation stages.

Use of phytases in fish and shrimp feeds: a review

Abstract: Phytases have been employed in animal feeds for several years, used primarily for reducing the environmental impact and phosphorus loads of farm effluents. Beneficial effect of dietary phytase has been associated with the limited ability of monogastric animals to utilize dietary plant phytates. To date, numerous studies have shown the positive effect of phytase supplementation on the availability of dietary phosphorus and trace minerals within plant-based feeds for monogastric farm animals, including farmed fish and shrimp. Individual feed ingredients may also be improved with phytases as an exogenous treatment, also termed pre-conditioning dephytinization prior to mixing. This review presents data on the potential benefit of phytase application for fish and shrimp species in improving digestibility of phosphorus and other minerals as well as organics nutrient fractions such as protein, amino acids and lipids.

Effects of cryopreservation on mitochondria of fish spermatozoa

Abstract: The development of sperm cryopreservation has enabled transcendental changes to occur in the reproductive biotechnology of both mammals and fish; it has become a basic tool for animal improvement. Nevertheless, these protocols cause damage to cell structure and physiology, altering sperm functioning due to cryo-injuries during freezing and thawing. However, studies of the effects on the structural, functional and genomic stability of the mitochondria in fish spermatozoa during cryopreservation are still lacking. The object of this review was to analyse the effect of cryopreservation on mitochondrial metabolic pathways in fish spermatozoa. This effect is related with the bioenergy mechanism for flagellar movement during the activation of sperm motility. In teleost fish, the mitochondria may be cylindrical, spherical or irregular in shape and adhere in a helicoidal or conical pattern to the middle piece. The salmonidae have only a single mitochondrion, but this may vary in other species; the mitochondria provide the flagellum with energy during sperm motility, when sperm respiration is essential. The effects of cryopreservation can induce structural damage to the mitochondria, altering the biochemical process involved in ATP production and thus causing a reduction in sperm motility. Fragmentation damage to nuclear DNA and diminution in sperm motility is mainly associated with damage to the structure and metabolic functioning of the mitochondrion. A direct correlation exists between the mitochondrial membrane potential (transmembrane integrity, ∆Ψm) and the motility and fertilizing capacity of the cryopreserved spermatozoa, confirming that this organelle is the energy nucleus of the spermatozoon and that the cessation or prolongation of motility and successful fertilization depend on the availability of ATP in the spermatozoa. Further works are need to incorporate biotechnology studies, at cell and molecular level, of the possible effects of cryopreservation on mitochondrial DNA, enzymatic or metabolic modifications of the citric acid cycle, and the oxidative phosphorylation process in the inner membrane, as well as studies of the mitochondrial ultrastructure. Thus, mitochondrial dynamics could be established as a potential target for therapeutic strategies.

Lymphocystis disease virus: its importance in aquaculture

Abstract: Lymphocystis disease virus (LCDV) is the causative agent of a well-known fish viral disease that is characterized by hypertrophy of fibroblastic cells in the connective tissue. This viral disease affects more than 125 wild and cultured species of teleost fish from marine and freshwater environments and has a cosmopolitan geographical distribution. In aquaculture systems, the prevalence of LCDV infection is very high, likely reflecting the horizontal transmission of this virus. The incidence rate of the disease may reach 70%, causing significant economic losses for the aquaculture industry. This review provides information on the taxonomy, viral properties, epizootiology and pathogenesis, diagnostic methods and control measures of LCDV infection in fish.

Planning and management for sustainable coastal aquaculture development in Santa Catarina State, south Brazil

Abstract: Marine aquaculture of bivalve molluscs is an important economic activity in Santa Catarina State, Brazil, with more than 5000 persons directly and indirectly involved and an annual revenue of US$ 18 million in 2013. In the first decade of this activity, a lack of proper regulation imposed multiple obstacles to the sustainable management of local shellfish farming. The occupation of marine space occurred in a disorderly manner, and the unplanned development led to unfavourable conditions that threatened the sustainability of the industry. This study describes how better planning and management tools have improved governance of marine aquaculture in Santa Catarina State. The process included development of a legal framework for aquaculture planning, elaboration of local development plans with a participatory and multidisciplinary approach, development of a geographic information system to identify favourable areas and creation of a Web-based aquaculture management system. The combined application of these actions, along with continuing extension services, is expected to contribute to the regulation of 837 shellfish farming areas, the expansion of farming activity, the mitigation of the environmental and visual impacts caused by coastal aquaculture and an increase in the public health of shellfish consumers. In this manuscript, we report an example of how the application of better planning and management of the aquaculture sector can prepare the industry for a sustainable growing cycle.

Sustainability vs. Quality in gilthead seabream ( Sparus aurata L.) farming: are trade-offs inevitable?

Abstract: European aquaculture industry should be at the forefront of sustainable development, providing healthy and safe food of the highest quality to the consumer, through an environmentally sound approach. The purpose of this review was to explore in what way the current drive for sustainability has affected what the consumer perceives as quality in fish, specifically in gilthead seabream, one of the most important farmed species in the Mediterranean. It focuses on nutritional aspects such as fish meal and fish oil replacement, quality tailoring through finishing strategies, the influence of different farming systems and the effect of slaughter stress on seabream quality. In general, fish meal and fish oil replacement with vegetable ingredients will result in changes in the fatty acid profile of the fillets, and consequently the potential health benefits seabream offers to the consumer. While organoleptic properties suffer little change, the impact of these ingredients on welfare has not been fully investigated. Further studies are also needed to evaluate the effect of land animal ingredients on seabream quality. In either case, although finishing strategies to restore essential fatty acids are not completely effective, seabream can still retain a high nutritional value. Information on the use of dietary supplements as finishing strategies is still extremely scarce. Regarding fish welfare, the high densities practised in intensive production systems pose concerns which warrant further research in this area. Furthermore, new alternatives for common harvesting and slaughter methods are needed to improve welfare, as traditional methods are clearly stressful.

A comparative analysis of four internationally traded farmed seafood commodities in China: domestic and international markets as key drivers

Abstract: The historical development, current status and development trends of four internationally traded farmed seafood commodities, tilapia, penaeid shrimp, macrobrachium prawns and catfish in China were reviewed. China is the world's largest producer of tilapia, penaeid shrimp and macrobrachium prawns but, although farming of channel catfish and some indigenous catfish species is well developed, striped catfish failed to become established. In terms of global exports, China ranks first for tilapia and third for shrimp, while macrobrachium prawns and catfish mainly support domestic markets. Endogenous, biological characteristics and market demand explain the different courses of development and the differentiated focus on domestic and international trade. Tilapia and whiteleg shrimp production illustrated rapid growth in both domestic and international markets based on their favourable culture characteristics and well-developed management systems. Huge production scale and domestic competition have resulted in China attaining a dominant and highly competitive position in the global tilapia market. High value of live freshwater prawns in local markets (and poor processing yield) has limited interest in exports, and local demand is also shifting the emphasis of shrimp production towards domestic markets, and a decline in its international market led to stagnation of channel catfish. Poor tolerance of seasonally low temperatures has restricted tilapia production to south China and completely inhibited the development of striped catfish as a commercial species. Live fish preference and costs of long-distance transportation have restricted domestic consumption of tilapia. A balance between domestic consumption and export is required to optimise future growth opportunities for the industry.

Socio-cultural dynamics shaping the potential of aquaculture to deliver development outcomes

Abstract: There is growing appreciation of the role of aquaculture in diversifying livelihoods of the poor. However, prevailing cultural norms and values, and social relations often influence its development outcomes, which we explore in this study. Socio-cultural dynamics affect the capacity of resource-poor and marginalized groups for the adoption and retention of aquaculture technologies. Gender norms and gender division of labour in a given community not only influence whether men or women participate in aquaculture but also shape their differential access to resources and position in decision-making, with knock-on effect for aquaculture productivity. Ethnic and cultural norms of collectivism, particularly in traditional fishing communities, support aquaculture efforts, but these are often overlooked by many development endeavours. Improved productivity does not necessarily translate into enhanced income, food and nutrition security. In many areas, benefits for women are lower despite their more active participation in aquaculture operations, post-harvest processing and marketing compared to men. Local power relations may limit access to land and water resources as well as inputs and services by the poor, restricting more equitable distribution of income from aquaculture. Nutritional outcome from aquaculture largely depends on preferences and acceptability of fish as a food and local customs regarding its preparation, preservation, cooking and distribution. Aquaculture interventions that take resource base and socio-cultural contexts into account are crucial for realizing increased income, food and nutrition benefits sustainably.

Impacts of environmental and biological stressors on immune system of Macrobrachium rosenbergii

Abstract: Macrobrachium rosenbergii commonly called giant freshwater prawn is a widely farmed crustacean in freshwater. Similar to other aquatic organisms, their growth and well-being is influenced by various physical, chemical and biological factors. We discuss about the critical growth limiting factors as well as disease causing agents and the potential immune molecules of M. rosenbergii that are proved to involve in preventing and/or responding to those limiting factors.

Penaeid shrimp cell culture and its applications.

Abstract: The aquaculture of penaeid shrimp has grown rapidly during the past three decades. However, shrimp aquaculture continues to be plagued by infectious disease, particularly of viral aetiology. Urgently needed are in vitro biological tools to facilitate early detection and diagnosis of penaeid shrimp viruses. An immediate need is the establishment of stable or continuous shrimp cell lines, which remains to be an elusive goal. Researchers have made significant advancements in the methodologies for primary shrimp cell culture. Also, new media and technologies including cell immortalization are presently under development. The principal goal of this review paper is to collate current attempts in the establishment of permanent shrimp cell lines by summarizing the latest research progress on penaeid shrimp cell culture studies, including general cultivation conditions, methods of cell preparation, types of media and their utilization and the development of immortal cell lines. In addition, current and potential applications of penaeid shrimp cell cultures in the various related research fields are also discussed in this review.

Strategies for managing diseases in non-native shrimp populations

Abstract: The shrimp industry is now largely based on Litopenaeus vannamei. Current strategies for disease management in Asia emphasizing exclusion and eradication with strict quarantine and importation protocols have not been effective in controlling disease epidemics. New diseases have been introduced on illegal importations; commercial shrimp populations are derived from imported SPF stocks susceptible to endemic diseases; and local breeding programmes are based on populations not resistant to a range of diseases. Broodstock are largely poorly adapted to local conditions and repeated disease epidemics occur. Strategies for disease management should concentrate on: (i) minimizing the risk of introducing new diseases to the region; (ii) development of populations more resistant to endemic diseases; and (iii) better management practices that minimize the likelihood of serious epidemics and delay infection, but do not depend on attempts to eradicate diseases already present. This can be implemented by building on the better management practices already established in the region and in addition: (i) applying strict quarantine procedures for diseases not reported in the region whilst making the processes sufficiently agile to reduce illegal introductions; (ii) eliminating standard rigid importation protocols and tailoring protocols in accordance with the disease situation of both the country of origin and destination; (iii) increasing genetic variation available within Asia by public sector support for programmes to enlarge the pool of genetic variation and encouraging collaboration with breeding programmes that encompass a broad genetic base; (iv) establishing selection programmes that permit reincorporation of animals exposed to disease into the breeding nucleus; and (v) establishing propagation systems that provide growers with high health status stocks without requiring overly strict SPF certification of facilities.

Analysis on the development and current situation of rainbow trout (Oncorhynchus mykiss) farming in Mexico

Abstract: The rainbow trout (Oncorhynchus mykiss), originally from North America, was introduced to Mexico in 1888 and gradually distributed to various areas of the country. Currently, rainbow trout are cultivated in Mexico under a number of production systems, but this sector has grown less than 1% annually for the last 10 years. The present review analysed the production status of rainbow trout in Mexico, describing the key situations and actors that have influenced the establishment and current level of aquaculture development. Since its beginnings, rainbow trout cultivation in Mexico has depended on egg import due to insufficient egg and fry production by national hatcheries. Moreover, the industry is deficient in regard to a number of aspects in the production and management processes, with a notable necessity for specialists in the areas of production, health and sanitary diagnosis to rapidly and efficiently respond to situations such as low productivity or the presence of diseases. With such specialists, appropriate control and prevention decisions could be taken and acted upon. Likewise, the Mexican rainbow trout industry has high development potential and market expectations, but sector growth will require the active participation and commitment of competent authorities, in compliance with established Mexican regulations and laws, which are oriented towards advancing and protecting the fish farming industry.

Circulation of water through a mussel raft: clearance area vs. idealized linear flows

Abstract: This study suggests revision of ecological concepts as food depletions and/or water flow reductions based on idealized linear flows through mussel rafts. We offer an alternative based on the extension of the clearance area, defined as the area affected by the nonlinear effects produced by each raft and surroundings ones. These conclusions are supported by our results, which indicate that (i) the preferential entry of water through a mussel raft does not occur through the bow, contrary to previously thought, and (ii) the intraraft circulation is strongly influenced by the orientation of the raft relative to the background current direction and does not follow a defined pattern. Intraraft circulation is assessed by means of four current metres installed at each side of the raft and the dimensions of the clearance area using long-term data provided by GPS and compass. While both intraraft circulation and clearance area dimensions are mainly controlled by tide, the net water exchange through the raft is reasonably explained by wind (velocity and direction) and river discharges.

A bioeconomic approach to optimize mussel culture production

Abstract: The fast rise of aquaculture practices during the last decades has increased the need of adopting culture strategies to optimize production and guarantee the sustainability of the sector. This study aimed to provide a management tool to help mussel farmers identify optimal culture strategies and use production inputs efficiently. For this purpose, we evaluated the productivity and efficiency of different stocking densities and culture durations by the joint application of parametric and nonparametric frontier analysis at the farm scale. The translog production function outperformed the Cobb–Douglas model currently applied in most farm-scale frontier analyses. This model estimates that the optimal culture density is ca. 700 ind m−1, given that at lower densities, efficiency decreases (under-usage of available space) and mussel quality did not improve, and at higher densities, mortality and dislodgements from the ropes led to economic losses. This work also showed that marginal analysis does not provide an accurate estimation of the economic efficiency when unitary costs and prices are not constant. According to the Malmquist indices, mussel farmers should shorten the culture period to improve their productivity. All these results support the joint use of parametric and nonparametric frontier analysis as management tool for optimizing input use and scheduling aquaculture production.

Identifying risk factors associated with White Spot Disease outbreaks of shrimps in the Gulf of California (Mexico) through expert opinion and surveys

Abstract: White spot disease is one of the most serious problems in the shrimp-farming industry in Mexico. An assessment of risk of an outbreak of the disease could be useful for farmers making decisions concerning early harvest to minimize economic losses. A group of researchers identified the most important risk factors, classified in four broad categories: management variables at the regional level, environmental variables at the regional level, management variables at the farm and population variables at the farm. For each variable, categories were defined and a risk score assigned. To validate these scores, a survey was carried out with 65 stakeholders. A semi-quantitative risk assessment model was proposed and implemented as a questionnaire containing 21 risk variables with weighted scores. The most important risk factors were the period of fallowing within farm's region and health quality of larvae. Also important were estimated level of viral load and virus detection in wild hosts in the surrounding area, pond water temperature, length of fallowing period of pond, vector control at water intake and stocking density. The overall estimated risk was calculated as the sum of all scores with a further adjustment, according to maximum and minimum total scores. Three risk levels for white spot disease outbreak at ponds are based on estimated risk: low (≤0.2), moderate (0.2–0.4) and high (≥0.4).

Harvesting time optimization and risk analysis for the mariculture of Kappaphycus alvarezii (Rhodophyta)

Abstract: Kappaphycus alvarezii (Rhodophyta) is an important source of carrageenan, which is commercially cultivated with economic benefits worldwide. In this study, we determined the optimal harvesting time and risk analysis for the mariculture of K. alvarezii in a semi-intensive commercial cultivation farm using a simulation model. Different growth models were analysed (Von Bertalanffy, Potential, Logistic and Gompertz) for the bioeconomic model developed in this study. Seawater temperature and solar irradiance functions were included as variables with major influence on seaweed growth. The Gompertz growth equation was chosen in accordance with Theil′s statistics and the difference between observed and simulated data. Under the conditions and assumptions considered for this analysis, the scenario that generated the highest profits (USD$ 3353.11) was that for a culture cycle of 135 days and a total biomass production of 13 708.47 kg dry weight cycle−1. Uncertainty was also included using probability density functions through random variables for seawater temperature, solar irradiance and sale price. Different harvest scenarios were obtained through Monte Carlo analysis; decisions under risk conditions and probabilities of being above or below reference points are presented. The results indicated lower risk at optimum harvesting time when the probability of exceeding the established target reference point for the present value (USD$ 2515.15) and biomass produced (34 271.17 kg fresh weight) were around 19.26% and 56.47%, respectively. Discussion on the implications of the use of this analysis for seaweed cultivation management is presented.