Showing papers in "Developments in Aquaculture and Fisheries Science in 2015"

Aquaculture, Stock Enhancement, and Restocking

Abstract: Summary The production value of Apostichopus japonicus aquaculture surpasses that of all other marine species cultivated in China. This chapter presents the various production modes, including industrial (indoor) culture, pond (cofferdam) culture, suspended culture, and sea ranching of A. japonicus . Different facilities, production systems, techniques, and management schemes are outlined. New technologies applicable to industrial culture and novel systems developed in recent years for the culture of A. japonicus in ponds, and for stock enhancement in near-shore and off-shore areas, are also discussed. This chapter provides general guidelines and can hopefully be used as a reference for researchers or managers working on the culture and protection of A. japonicus and other sea cucumber species.

Nutritional and Medicinal Value

Abstract: Summary Sea cucumber has been regarded as a highly nutritional food since ancient times, giving it a high economic value today, and making it one of the “eight valuable seafoods” in China. The most prized species in China, Apostichopus japonicus, is high in protein, low in fat, and it contains an abundance of trace elements and other inorganic salts. Furthermore, it is a great source of functional molecules, such as polysaccharides, collagen proteins, and lipids, among others. This chapter introduces the nutritional value of A. japonicus and the composition and function of its major bioactive molecules.

Development, Settlement, and Post-settlement Growth

Abstract: Summary The sea cucumber Apostichopus japonicus is an economically important species along the northwest Pacific Coast, including China, Democratic People’s Republic of Korea, Republic of Korea, Russia, and Japan. In the present chapter, we summarize knowledge on the embryonic and larval development of A. japonicus, as well as the impacts of various environmental factors on these processes. A. japonicus is a dioecious broadcast spawner. Its life cycle can be divided into eight major stages: fertilization, blastula, gastrula, auricularia, doliolaria, pentactula, juvenile, and adult. The fertilized, mainly demersal eggs measure ∼165 μm in diameter, and develop into freely rotating blastulae in 14 h at 20–21 °C. The embryos then develop into auricularia larvae over the following 34 h, at which time they gain the ability to feed. When the auriculariae grow to their maximum size of ∼800–950 μm, they shrink and transform into doliolariae, and subsequently into pentactulae after completion of metamorphosis. The development of buccal and ambulacral podia indicates the onset of the juvenile stage. It takes almost two years for A. japonicus to reach sexual maturity, and the life span of this species is commonly estimated to be at least five years. The influence of environmental factors, such as temperature, salinity, and planktic food, on larval development and growth, as well as substrate selection during metamorphosis are discussed. Transitional functions of locomotory and feeding organs in larvae, behavioral characteristics during settlement, and interindividual variations in early growth rates are also examined.

Aestivation and Regeneration

Abstract: Summary The present chapter details and discusses the processes of aestivation and organ regeneration in Apostichopus japonicus . High seawater temperature in the summer triggers a dormant state, known as aestivation, in almost 100% of mature individuals. During this phase, A. japonicus undergoes major tissue loss, metabolic rate depression, and immune system modification. Morphological, molecular, and transcriptomic studies on aestivation in A. japonicus have helped define its main stages as well as the mechanisms of hypometabolism and gene expression silencing that underlie it. When A. japonicus is exposed to stressful conditions, it can shed most of its internal organs, which will later be regenerated. The process of intestine regeneration was investigated through light and electron microscopy analysis. The general underlying mechanisms mainly involve morphallaxis at the early stage and epimorphosis at the later stage. The gene expression profile during intestine regeneration in A. japonicus was constructed to provide significant information for future research on regenerative pathways.

Apostichopus japonicus in the Life of Chinese People

Abstract: Summary Holothurians or sea cucumbers, especially Apostichopus japonicus , have been part of the diet of the Chinese people for centuries; they are also woven into the fabric of Chinese culture as one of the most important foods. From legends to real facts, and from ancient emperor dynasties to the present day, this chapter covers the drivers of the sea cucumber industry in China and tries to explain why such tremendous demand exists worldwide for an unassuming and strange-looking marine invertebrate. The origin, evolution, and distribution of A. japonicus are also introduced, together with its proven and putative medicinal properties.

Apostichopus japonicus: A Key Species in Integrated Polyculture Systems

Abstract: Summary Integrated multitrophic aquaculture (IMTA) of deposit-feeding sea cucumbers with other species would be beneficial economically (increased harvests) and environmentally (decreasing farm wastes). On the eastern Asian coast, the sea cucumber Apostichopus japonicus is considered an excellent candidate for marine IMTA systems. The use of A. japonicus can mitigate the accumulation of particulate organic waste produced by other species, due to its deposit-feeding behavior. The experimental studies and commercial practices of sea cucumber IMTA in China started in the late 1980s, and the feasibility of coculture of A. japonicus with fish, shrimp, bivalves and/or macroalgae, abalone, and sea urchin has been tested in China, Japan, and Republic of Korea in recent years. Moreover, the bioremediation capability of A. japonicus on organic wastes discharged from bivalves and/or macroalgae systems has been evaluated in the context of coculture or polyculture. Future breakthroughs in the field of sea cucumber IMTA are anticipated in the years to come.

Broodstock Conditioning and Spawning

Abstract: Summary This chapter focuses on the gametogenic maturation and spawning of Apostichopus japonicus and explores the influence of environmental factors on gamete release. It also presents and discusses artificial spawning induction techniques. Food supply and water temperature have been identified as important mediators of gonad maturation in A. japonicus. Temperature shocks, exposure to air under shade, and exposure to running water have been used to induce spawning under laboratory conditions for the purpose of sea cucumber seedling production. In recent years, scientists have also identified other factors, such as variations in salinity, pH and light, as potential inducers of gamete release in this species.

Apostichopus japonicus in the Worldwide Production and Trade of Sea Cucumbers

Abstract: Summary Sea cucumber resources occur in oceans all over the world. Among them, one of the most common temperate species is the sea cucumber Apostichopus japonicus, which has been cultured successfully in China. The international trade structure for sea cucumber is different from that of typical marine products. About 90% of trade volume goes through Hong Kong and Singapore, while the Chinese mainland is the main consumer market. In most countries, sea cucumber is mainly exported in its dried form, whereas fresh, salted, and frozen products only take up a small part of the international trade. In this chapter, the production, import and export trends, and the main markets for all commercial species of sea cucumbers will be discussed. Emphasis will be placed on the local trade of A. japonicus in China, Japan, and Democratic People’s Republic of Korea and Republic of Korea, and on market incentives and developments in China.

Feeding, Digestion, Nutritional Physiology, and Bioenergetics

Abstract: Summary The sea cucumber Apostichopus japonicus is a deposit feeder. This chapter examines its feeding biology, focusing on feeding habits, selectivity, and seasonal variation in food sources, digestive enzymes, and nutritional requirements. The influence of feed composition, including protein sources, on growth rates and metabolic and immune responses are also discussed.

Chapter 9 - Environmental Drivers of Behavior

Abstract: Summary Environmentally driven behaviors are those that are mediated by environmental cues, such as temperature, salinity, and light. This chapter explores environmentally driven behavior in embryos, larvae, juveniles, and adults of Apostichopus japonicus . It covers their movement, migration and aggregation, timing of spawning, as well as growth and feeding patterns. It also outlines the factors that affect habitat selectivity, migration, and distribution of A. japonicus at different periods. Knowledge of how behaviors of A. japonicus are mediated by environmental factors is the basis for developing adapted facilities and strategies for their culture and stock enhancement, as well as better management and protection of the remaining natural populations.

Spatial Distribution, Population Structures, Management, and Conservation

Abstract: Summary The sea cucumber Apostichopus japonicus is one of the most important commercial species in Asian countries including China, Japan, Russia, Republic of Korea, and Democratic People’s Republic of Korea. Catches of wild A. japonicus have significantly declined over the past years throughout its distribution range, and this species is now being massively produced through hatcheries and sea ranching. This chapter introduces the larval, juvenile, and adult spatial distributions, population structures, and dynamics as well as some data on fishery management and conservation.

Apostichopus japonicus: Fisheries, Trade, and Foodways in Japan

Abstract: Summary Nearly all sea cucumbers Apostichopus japonicus currently harvested in Japan are wild, not cultured. This is one of the prominent characteristics of Japanese A. japonicus fisheries. Dried A. japonicus has been a major export commodity from Japan to China for at least 350 years. Japanese also consume sea cucumbers but they have developed a taste for them since the seventeenth century that differs from the Chinese model. This chapter explores the current sea cucumber fisheries in Japan: fisheries regulations, as well as landing and exporting data. Around the mid-2000s, new types of sea cucumber products, such as salt-preserved body wall, became common Japanese products to be exported to China. To confirm the new trend in the sea cucumber trade, an exploration of Japanese A. japonicus on the Hong Kong and Chinese markets is provided. Moreover, problems related to the shift of sea cucumber processing from dried to salt-preserved products is discussed. Finally, the chapter introduces efforts of local sea cucumber fishermen and processors to enhance the domestic sea cucumber market in order to maintain sustainable sea cucumber fisheries.

Chapter 2 – From Fisheries Toward Aquaculture

Abstract: In China, Apostichopus japonicus has a long history of consumption, owing mainly to the health benefits and medicinal properties attributed to sea cucumber. The traditional dive-fishing method for A. japonicus is still being used in China today. With the socioeconomic boom in the 1990s, the market demand for sea cucumber increased considerably and led to the sharp decline of natural resources. Consequently, A. japonicus aquaculture emerged and became the most important source of A. japonicus on the market. With increasing wealth and consumer demand in China, A. japonicus aquaculture is expected to expand in years to come, despite limiting factors, such as diseases, environmental deterioration, and space constraints.

Processing and Cuisine

Abstract: Summary Sea cucumber, much like ginseng, is considered among the most nourishing foods in China. The traditional way of processing sea cucumber (i.e., dried body wall or beche-de-mer) has been passed along for more than 1000 years. The advantages of this preparation are its simplicity, low cost, stability (it keeps >10 years in storage), and ease of transportation. Other traditional methods include salted dried sea cucumber, salted fresh sea cucumber, unsalted fresh sea cucumber, and frozen dried sea cucumber. Modern processing methods include vacuum freeze drying, heat drying, microwave freeze drying, heat pump drying, instant sea cucumber, canned sea cucumber, and high-pressure processing, to name only a few. In this chapter, we outline and discuss the various processing methods and some of the most common recipes developed over the years around this exceptional seafood.

Chapter 4 – Anatomy

Abstract: Like other sea cucumbers, Apostichopus japonicus has a roughly cylindrical shape. It is radially symmetrical along its longitudinal axis, and has weak transversal bilateral symmetry with defined dorsal and ventral surfaces. There are five ambulacral zones along the length of the body from the mouth to the anus – two on the dorsal surface, and three on the ventral surface. The anterior end of the animal, bearing the mouth, corresponds to the oral pole of other echinoderms (e.g., sea urchin and sea star). The posterior end, where the anus is located, corresponds to the aboral pole. A. japonicus has a well-developed respiratory tree, but no Cuvierian organ. This chapter describes and discusses the anatomy of the body wall, endoskeleton, coelom and coelomocytes, as well as the nervous, digestive, respiratory, water vascular, hemal, and reproductive systems of A. japonicus. The macrostructural, microstructural, and ultrastructural aspects are covered in detail.

Chapter 15 – Immunology and Diseases

Abstract: Summary Knowledge of the immune defenses in Holothuroidea, and more generally in Echinodermata, is considered to be important due to their phylogenetic vantage point, which can help infer both the early evolution of bilaterian immunity and the underpinnings of the vertebrate adaptive immune system It is also crucial to determine how immunological functions are affected by environmental stresses The first segment of this chapter details cell types in the coelomic and hemal systems of sea cucumbers and considers the influence of environmental stressors on the immune response of A japonicus The second segment focuses on the response to pathogens With the rapid expansion and intensification of sea cucumber farming, the incidence of diseases has increased and causative agents have been investigated in various life stages This chapter discusses symptoms and treatments of various infections, including the syndromes of rotting edges and ulceration of the stomach in auricularia larvae, autolysis of young juveniles, as well as skin ulceration, epidermis erosion, and body edema of adults triggered by bacteria, fungi, and parasites

Habitat Enhancement and Rehabilitation

Abstract: Summary This chapter outlines the main threats to coastal environments and to populations of Apostichopus japonicus and reviews the methods currently being developed to mitigate habitat loss. In the wild, A. japonicus usually lives in coastal areas where there are healthy rocky reefs (covered with macrophytes) or in seagrass beds at depths of 3–10 m. Due to pollution of the marine environment and overfishing, the habitat of A. japonicus has deteriorated gradually, and suitable environments for its populations to thrive are becoming rarer every year. Efforts are therefore being made to enhance or replenish the wild stocks of A. japonicus by deploying appropriate types of artificial reefs, and by rehabilitating seagrass beds.

Larval, Juvenile, and Adult Predators

Abstract: Summary The survival of the sea cucumber Apostichopus japonicus in various land-based and field aquaculture systems is negatively correlated with the abundance of potential predators. Different predators affect the various life stages. Copepods, such as Microsetella sp. and Tigriopus japonicus , can compete for food and space with sea cucumber larvae, and they can also be predators of juveniles A. japonicus themselves) are potential predators of larvae and newly settled juveniles. Juvenile sea cucumbers with a body length 10 cm have few known predators. Various methods have been developed in an effort to protect the various life stages of A. japonicus against predators. In hatcheries and nurseries, trichlorphon can eliminate copepods without harming early life stages. In grow-on ponds and coastal areas, rocks and artificial reefs are used to provide shelter from predators. Bottom trawling, trapping, and manual removal by divers may also be used to decrease the abundance of predators in aquaculture systems.

Taxonomy and Identification

Abstract: Summary Sea cucumbers (Echinodermata: Holothuroidea), also commonly called holothurians or holothuroids, have traditionally been classified through their morphological phenotype, particularly the analysis of their anatomy, including tentacles, papillae, and ossicles (minute calcareous elements). Nowadays, traditional approaches are being complemented by molecular techniques applied to systematics and taxonomy. In the present chapter, we discuss the identification and taxonomy of holothuroids with specific references to Apostichopus japonicus. We also describe morphological variability (e.g., color and shape) in A. japonicus that complicates the identification of live specimens and dried processed products (beche-de-mer).

Apostichopus japonicus: “Dolgi Haesam” in the Republic of Korea (South Korea)

Abstract: Summary Sea cucumbers in the Korean Peninsula have been well known as nutritious and wholesome seafood, often called “ginseng of the sea.” A number of edible color variants of Apostichopus japonicus are harvested along Korean coastal areas and conventionally divided into red, blue, and black sea cucumbers. The annual catch of wild sea cucumber in the Republic of Korea decreased from the early 1980s due to an increase in fishing pressure, the deterioration of the coastal environment by pollution, climate change, and habitat loss driven by land reclamations. Since the mid-2000s, however, sea cucumber production began to increase mainly in response to new management measures implemented by the government, such as the release of seedlings grown in aquaculture facilities. As a health food, with an eco-friendly image, sea cucumber has a great potential for exports to foreign markets, especially in neighboring countries, such as Japan and the People’s Republic of China. Thanks to the governmental initiatives and increasing demand in and outside the country, sea cucumber aquaculture is expected to grow rapidly in the future.

Chapter 12 - Albinism

Abstract: Albinism is widespread in the animal kingdom and is caused by the absence of melanin in the hair, eyes, or skin. Research on albinism has mainly focused on humans and mice and there is little directed research on albino echinoderms. In this chapter, the occurrence and mechanisms of albinism in the sea cucumber Apostichopus japonicus are discussed, and we conclude as follows: (1) The lack of melanin in the body wall is the direct cause of albinism in A. japonicus; (2) the lack of melanocytes and melanin synthesis in melanosomes are histological characteristics of albino A. japonicus; and (3) the significantly low microphthalmia-associated transcription factor (MITF) and astacin expression levels in A. japonicus are the molecular causes of albinism.

Chapter 13 - Tissue Biochemistry

Abstract: The sea cucumber Apostichopus japonicus has a long history of use as a traditional tonic consumed by the Chinese and Japanese for its nutritional value as well as medicinal properties. Most of the edible and medicinal properties are derived from the body wall tissue (in China) and digestive tract and gonad (in Japan). In this chapter, the proximate composition (moisture, crude protein, carbohydrate, lipid, and ash content), amino acid, fatty acid, vitamins, and minerals in the different tissues of the sea cucumber A. japonicus are outlined.

Apostichopus japonicus in the Democratic People’s Republic of Korea

Abstract: Summary This chapter provides a brief introduction to the history of consumption and fishery of the Japanese sea cucumber, Apostichopus japonicus, in the Democratic People’s Republic of Korea (ie, North Korea) Commercial fishing of this holothurian species dates back to the early fifteenth century; collection was mainly by hand by women skin divers Fishing intensified in the early 1900s with the introduction of SCUBA equipment, which led to a gradual decline of the wild resources This chapter also presents information on the recent development of aquaculture programs aimed at restoring the natural resources and boosting production, both for the domestic markets and the lucrative export markets