Mariculture

Reports the results of a survey of wholesalers and retailers of giant clam shells in Southeast Queensland undertaken in August 1989. The most common variety of clam shell was that of Hippopus hippopus (the horseshoe clam) with that of Tridacna squamosa (the fingernail clam) being the second most frequent. Shells of Tridacna porcellanus (the china clam) and of Tridacna gigas were also available but in extremely short supply. Only shells of these species appear to be in real demand. Shells of other species have unsatisfactory characteristics but shells of the species in demand are not perfect substitutes - the market is segmented. Information is presented on prices and quantities of clam shells sold. Currently, there seems to be an Australian market for about 100,000 to 120,000 clam shells per year. Practically all clam shells were imported from the Philippines but supplies are becoming scarce as CITES takes effect and natura1 stocks become exhausted. This is reflected in the unavailability of larger shells and the sale of shells of lower quality than in the past. Tourists possibly account for 60 - 70 per cent of sales of clam shells but only a small percentage (10%?) of sales are to overseas tourists because of weight problems. A reasonably high proportion of clam shells appear to be purchased by restaurants and directly by householders. Practically all shell outlets expressed interest in obtaining clam shells from farms and provided information on the type of shells which they would like to see produced. Most thought that there would be a ‘good’ market for clam shells obtained by mariculture.

This paper presents the resuls of growth rate and condition index analysis of Mytilus galloprovincialis in integrated system and monoculture. The aim of this study was to show if there are differences in growth and condition index of mussels between integrated multi-trophic aquaculture (IMTA) and monoculture farming. The growth rate and condition index were monitored during a 13-month study at three different sites: 1) close to fish cages (NBL), 2) 100 m removed from fish cages (NUD), 3) at a monoculture mussel farm (SVN) around 8 km far away from cages. The most intense growth of mussels was recorded in spring, and the least intense in summer. After 13 months, monitored individuals at all three locations achieved commercial size. The growth rate was very similar at all sites. The condition index showed spatial and temporal differences. Condition index values on site NUD were mostly higher compared to SVN and NBL, which were very similar, exept for the period from October to December when CI was similar on NBL and NUD site and higher in comparation with SVN. CI values on NBL an NUD site during cold period indicate on fact that mussels probably feed on the nutrients from fish farm origins.The highest mortality rate was recorded at the NBL site, probably due to the effects of fouling organisms.

На базе полевых исследований проведен анализ деятельности китайского капитала на юге Дальнего Востока. Выявлен масштаб, отраслевое распределение и ключевые тренды китайского экономического присутствия в приграничных с КНР регионах РФ. Показано, что ослабевающие конкурентные преимущества инвесторов из КНР, экономическая политика в РФ и приход крупных российских компаний стимулируют вытеснение китайских инвесторов из традиционных сфер хозяйствования на Дальнем Востоке.

A cage is a space enclosed with some type of mesh forming a container for aquatic animals to grow. It is typically box-shaped or tube like structure with a rope system which supports the netting material, gives shape and allows for tying to the raft unit. In box type cages, the cage is constructed of four panels at the sides and one bottom panel. Anti-predator nets are deployed around the cage to prevent entrance of predators such as sharks and sea lions into the cages. An additional net would be provided on top of the cage to prevent bird predation.

Improved coral cultivation will facilitate the reduction of wild harvesting, reef restoration, preservation of biodiversity, and the use of corals as model experimental organisms. In this study, we examine species-specific responses in growth and survival of corals from the effects of light, water motion and artificial (i.e. non-living aquarium trade) food supplements. Three species representing distinct, diverse and abundant coral genera were chosen (Montipora capitata(Mc), Porites compressa (Pc) and Pocillopora damicornis (Pd)) for three experiments to examine: (1) the interaction of water flow and light on growth and survival of Mc and Pc; (2) the effects of artificial foods on Mc, Pc and Pd; and (3) the effects of increasing dosage of artificial foods in an open system on Mc and Pc. Pc thrived at the highest light levels with low flow, while Mc exhibited bleaching and reduced growth in the same conditions and grew best in shaded treatments. High constant flow (~11 cm s-1) resulted in slightly less overall growth than low constant flow (~4 cm s-1). Some artificial foods resulted in a significant increase in growth in Mc and Pd, but not in Pc. These combined results suggest that Mc may be more heterotrophic than Pc. This study illustrates that each species has unique requirements for optimal growth conditions that can be determined by relatively simple and low cost experiments, but that ideal conditions for one species might not be generalized to others.

Tujuan dari praktek lapang marikultur adalah untuk mengetahui potensi dan hambatan yang dihadapi pembudidaya rumput laut pada tiga desa di Kecamatan Wolo, Kabupaten Kolaka. Sedangakan manfaat yang akan diperoleh adalah dihasilkannya rekomendasi untuk pihak terkait dalam menindaklanjuti seluruh permasalahan yang dialami pembudidaya rumput laut guna peningkatan hasil produksi.

Diseases in marine invertebrates are increasing in both frequency and intensity around the globe.
Although diseases in wild groups are often not well documented, diseases in individuals which offer
some commercial value are often well documented and subsequently well studied. Particularly, those
associated with mariculture or the commercial fisheries. These include many Holothuroidea, and
numerous crustacea and mollusca species. Pathogens / parasites consisting of both prokaryotes and
eukaryotes from all groups have been associated with such diseases including bacteria, viruses, fungi
and protozoa. Viral pathogens appear to be an increasingly important group and research into this
group will likely highlight a larger number of diseases and pathogens being described in the near
future. Interestingly, although there are countless examples of the spread of disease usually
associated with transportation of specific infected hosts for development of aquaculture practises, this
process appears to be continuing with no real sign of effective management and mitigation strategies
being implicated. Specifically even in well developed countries such as the UK and the US, even
though live animal trade may be well managed, the transport of frozen food appears to be less well so
and as evidence suggests, even these can transmit pathogens when used as a food source for
example.

While there is increasing recognition among archaeologists of the extent to which non-agricultural societies have managed their terrestrial ecosystems, the traditional management of marine ecosystems has been largely ignored.  In this paper, we bring together Indigenous ecological knowledge, coastal geomorphological observations, and archaeological data to document how Northwest Coast First Nations cultivated clams to maintain and increase productivity.  We focus on “clam gardens”, walled intertidal terraces constructed to increase bivalve habitat and productivity.  Our survey and excavations of clam gardens in four locations in British Columbia provides insights into the ecological and social context, morphology, construction, and the first reported ages of these features. These data demonstrate the extent of traditional maricultural systems among coastal First Nations, and coupled with previously collected information on terrestrial management, challenges us to broaden our definition of “forager” as applied to Northwest Coast peoples. This study also highlights the value of combining diverse kinds of knowledge, including archaeological data, to understand the social and ecological contexts of traditional management systems.

Archaeological evidence from oyster shells recovered from Shell Mound (8LV42), located in the Lower Suwannee region of Florida’s Gulf Coast, indicates that maricultural practices were used by coastal inhabitants when the scale and intensity of oyster procurement increased during a time of ritual economy and mound-building activity from A.D. 550–650. Shell Mound was transformed from a quotient village site to a coastal civic-ceremonial center, likely related to the burial complex on Palmetto Mound (8LV2), during a time of environmental and sea-level uncertainty. The mound was constructed in less than two centuries, accumulating as many as 1.2 billion oysters. Mariculture, which has been in practice since at least 2,000 years ago, was likely practiced at Shell Mound as a mechanism to prevent over-exploitation of the resource and to sustain the local oyster reefs for daily subsistence, feasting, and mound construction. Analysis of 3,252 oyster shells from a single test unit that encompasses three phases of occupation shows that culling and shelling were practices used when the scale and intensity of oyster harvesting increased.

Sediment samples under the Longline and Stake Method of mussel culture were analyzed to determine their % Organic Matter and % Carbon contents which can help in prevention of enhanced sedimentation and water fouling. Using the chromic acid method for the soil analysis, the % OM and % C under the Longline method was recorded having higher measures of organic matter and carbon content. Results showed that the possible cause of increased organic matter and carbon content is by the location of the culture methods being in close proximity from the bay area, where runoff from heavy rains wash away Organic matter and Carbon from the land and into the bay. Moreover, the study concludes that not only the mussels cause the reduction of soil quality but anthropogenic activity accelerates sedimentation and increase of nutrient levels that could cause eutrophication.

Keywords: sedimentation, longline method, mussel culture, organic matter, carbon

Four species of giant clams, Tridacna maxima, T. squamosa, T. derasa and T. crocea, were cultured in outdoor raceways for 364 days at the Waikīkī Aquarium and the Oceanic Institute on the island of O‘ahu, Hawai‘i, USA.  Growth of each species was compared among individuals grown with and without supplemental phytoplankton feeding, and directly on the substrate or mounted on concrete plugs in low pH, high nutrient seawater.  Among clams cultured with and without supplemental phytoplankton (Chaetoceros spp.), feeding resulted in significantly lower mortality in all species but T. deresa, whereas growth was significantly higher among fed clams for all species except T. squamosa. Tridacna derasa showed roughly a three-fold increase in growth when fed (88.5 g ± 4.4 SD) than when unfed (26.0 g ± 2.1 SD), whereas T. maxima growth was substantially lower, but nearly 10-fold greater in response to feeding (9.0 g ± 1.9 SD). The overall mortality rate of juvenile clams was significantly lower in the fed (44.4 ± 10.0%) than the unfed (71.8 ± 9.6%) trials, with the greatest effect observed in mortality of T. maxima (fed 15% versus unfed 80%) and T. squamosa (fed 65% versus unfed 95%). None of the T. squamosa remained on concrete plugs for the duration of the experiment. Among the remaining three species, there was no difference in either wet weight or shell length for T. maxima and for wet weight only in T. derasa on (186.5 g ± 16.1 SD) and off (147.0 g ± 6.0 SD) the concrete plugs.  In contrast, T. crocea had significantly greater shell growth off the plugs (14.3 mm ± 1.0 SD versus 8.5 mm ± 1.7 SD) but significantly greater gain in wet weight on the concrete plugs (26.3 g ± 1.5 SD versus 58.5 g ± 2.5 SD).  The seawater wells used for this study are well characterized with elevated levels of inorganic nutrients and higher pCO2 relative to tropical ocean waters, roughly approximating predictions for future oceanic conditions under IPCC IS92a emission scenarios. In comparison to previous studies in natural seawater, T. derasa had a significantly higher shell growth rate in the high-nutrient, low-pH well water.  In contrast, T. maxima and T. squamosa had significantly lower growth rates in low pH, whereas growth of T. crocea was not significantly different between low pH and ambient seawater.  These experiments demonstrate species-specific differences with each treatment, which cautions against making broad generalizations regarding the effects of substrate type, feeding effects, nutrient enrichment, and ocean acidification on tridacnid culture and survival.

Reports on the results of research based on the test-marketing of giant clams as aquarium specimens in Brisbane, Australia, in the third-quarter of 1991. Giant clams were distributed through six cooperating retail aquarium outlets and sold at a reasonable commercial price. This was considered to be $10 – 13 for T. crocea of 2.5 - 5cm (1 – 2") in size. Clams were supplied free of charge to cooperating retailers. In return they were required to complete survey forms and to try and ensure that purchasers of their clams did likewise, and to take care of the clams in their possession.
The results indicate that giant clams are rated as very good aquarium specimens and in that respect were considered to be about as equally desirable as coral and anemones. The most desired size of clams was considered to be in the range 5 – 10cm (2 – 4") and purchasers on average thought that a price of around $19 would be reasonable for such clams, even though retailers suggested a slightly lower price.
The margin of mark-up available to retailers in Queensland for sales of giant clam aquarium specimens in the size range 2.5 – 5cm seems quite low, particularly given the cost of the permit required from the Queensland Department of Primary Industries. The permit and regulations enforced by the Queensland Department of Primary Industries are a major impediment to the development of the aquarium market in Queensland for giant clams. Apart from the expense involved for the retailer, purchasers are also required to hold permits from this Department. This places a major dampener on sales in Queensland given that permits must be obtained in advance by potential purchasers. Although commercial farming of clams exists in Queensland, farmers find it easier to export their products rather than to attempt to sell them in Queensland.
This report also provides information about a number of other issues affecting the market for giant clams as aquarium specimens e.g. availability of information on keeping them in home aquariums, characteristics of purchasers and so on. The results also indicate that the Australian market for giant clams as aquarium specimens is about 5,000 per year. This is a similar estimate to that made in 1989 on the basis of a different survey.

Our knowledge of what the denizens of the animal kingdom are up to, especially when humans aren’t around, has steadily increased over the last 50 years. For example, we know now that animals use tools in their daily lives. Chimps use twigs to fish for termites; sea otters break open shellfish on rocks they selected; octopi carry coconut shell halves to later use as shelters....The latest discovery has taken this assessment to new heights, literally. A team of researchers led by Mark Bonta and Robert Gosford in northern Australia has documented kites and falcons, colloquially termed “firehawks,” intentionally carrying burning sticks to spread fire. While it has long been known that birds will take advantage of natural fires that cause insects, rodents and reptiles to flee and thus increase feeding opportunities, that they would intercede to spread fire to unburned locales is astounding.....The worldwide attention given to the firehawks article provides an opportunity to explore the double standard that exists concerning the acceptance of Traditional Knowledge by practitioners of Western science.

Archaeologists and historians have demonstrated that marine resource management, or mariculture, has been practiced by coastal peoples worldwide for thousands of years. Typically evidence for these practices is in the form of ethnohistoric accounts or associated infrastructure (e.g. clam gardens). This paper presents methods for inferring oyster mariculture by using proxy evidence from attributes of the shell itself. The methods are applied to archaeological shell from a Woodland Period site on Florida's Gulf Coast, where it appears that two techniques of mariculture, shelling and culling, were practiced during a period of intensive large-scale and sustained harvesting.

Open-sea mariculture of the Philippine blue sponge Xestospongia sp. was established as a route for the production of the biomedically-important renieramycins. We assessed the effects of harvesting regime, culture period or periodicity, sponge translocation and farming methods to sponge survival, sponge growth, chemistry and bioactivity of sponge extracts. During the 12-month culture, sponge growth, renieramycin M content and an-tiproliferative activity of sponge extracts showed significant differences, depending on the culture period and location. Growth and renieramycin biosynthesis were minimally affected by temperature and may be driven by thermal-independent processes in the coral reef. Multiple harvesting of Xestospongia sp. was also favorable to growth and consequently, provided higher biomass and renieramycin M yields.

According to The State of World Fisheries and
Aquaculture 2012, a publication of the Food and Agriculture
Organization of the United Nations, five Asian nations topped the
world ranking of mariculture producers in 2010. In order, they
were China, India, Vietnam, Indonesia, and Bangladesh. Asia’s
maricultural production was 1,799,101 tons in 1970, accounting
for 70.1% of the world total. Since then, maricultural production
in Asia has continued to grow as a percentage of the world total
year by year. In 2010, Asian production reached 53,301,157 tons,
about 30 times the 1970 level and 89.0% of global production.
World production by maricultural environment shows that about
62.0% comes from freshwater, 7.9% from brackish water, and
30.1% from seawater. Since 2000, the trend is for freshwater
production to increase slightly and seawater production to
decline slightly. Given this background, promoting mariculture
to expand exports of fish and shellfish is a key issue of national
development plans in Indonesia, the world’s fourth largest
maricultural producer. However, maricultural technology is still
in the development stage, and production is not stable, plagued as
it is with problems like sudden, large-scale die-offs. Maricultural
technology can be broadly divided into egg and hatchling
production technology and cultivating technology. In Indonesia,
egg and hatchling production technology has been under
development for high-added-value milkfish and grouper through
the “Project for Development of Egg and Hatchling Production
Technology for Many Species,” begun in 1994. Since 2003,
organizations such as a national maricultural research center
have been transferring that technology to the private sector. On
the other hand, cultivating technology, which concerns raising
fish from juvenile to adult stages, is still under development.
Here, one issue is the establishment of maricultural technology
that enables stable production immune to regime shifts. The
authors have begun the observation of the marine environment
to establish maricultural technology in Indonesia with the
objective of enabling stable production and distribution of safe
and reliable fish and shellfish into the future.

Integral multi-trophic aquaculture (IMTA) is a form of aquaculture where
metabolic products of fish and uneaten food, which presents negative pressure
for ecosystem, can be used as food in lower trophic organisms as bivalves,
leading to the higher productivity of the entire system as well as reducing of
negative fish farming impact. The growth rate and condition index (CI) were
monitored in Mediterranean mussel (Mytilus galloprovincialis Lamarck,
1819) since January 2015 up to January 2016 on three different positions: NBL
– position near fish cages, NUD – position 100 m removed from fish cages
and SVN – monoculture. The most intense growth in mussels was recorded in
spring, and the least intense during summer. On the end of experiment, all
monitored individuals from all three positions achieved commercial size, 50
mm. Results of ANOVA showed that there are statistically significant
differences in growth rate among positions (F=36.32; p<0.001), while Turkey
post hoc test showed that growth rates on NUD and SVN position are similar
and significant higher compare to NBL. During most of investigated period,
CI was higher on NUD compare to other two positions, except in period
October to December, when CI was similar among NBL and NUD position
and statistically significant higher compare to SVN (ANOVA with Turkey
post hoc test), indicating on fact that during cold period mussels probably feed
on the nutrients from fish farm origins. The highest mortality was recorded at
NBL position, what is probably due to the effect of fouling organisms.
Obtained results indicate that additional and more detailed studies are needed
as well as monitoring of other biomarkers as C and N stable isotopes, with the
aim of determining the benefits of IMTA.

Outlines development strategies of firms which have engaged in giant clam mariculture, particularly Australian firms, with special attention being given to Reefarm Pty. Ltd., the longest surviving commercial company involved in giant clam mariculture. Considers methods which companies in this area have used for coping with business uncertainty; examines the development of Reefarm Pty. Ltd and the choice of product-mix by Reefarm. The product mix involves pearl oysters, and supply of giant clams for a variety of markets (the aquarium trade, seed sales, the restaurant trade for food and provision of tourism/educational services). The analysis indicates the importance of considering the development of firms from an evolutionary perspective.