THE MARINE PLANT RESOURCES
AQUACULTURE POTENTIAL IN THE BAHAMAS
A REPORT TO THE
FISHERIES TRAINING AND DEVELOPMENT
JAMES A. DEBOER, PH. D.
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1.2 Useage and demand for marine algae
1.3 Seaweed aquaculture
2. SEAWEED UTILIZATION AND FARMING IN THE CARIBBEAN
3. SEAWEED RESOURCES OF THE BAHAMAS
4. SEAWEED FARMING METHODOLOGY
4.1 Farming techniques for Eucheuma and Gracilaria
4.2 Environmental requirements
4.3 Seaweed farm management
4.4 Economics of seaweed farming
5. SEAWEED AQUACULTURE POTENTIAL IN THE BAHAMAS
5.1 Justification for seaweed aquaculture
5.2 Candidate species for seaweed farming
5.3 Environmental conditions in the Bahamas
5.4 Seaweed farm site selection
6. RECOMMENDATIONS FOR SEAWEED FARM DEVELOPMENT
ANNEX I ITINERARY
ANNEX II LIST OF PERSONS CONTACTED
ANNEX III REFERENCES
ANNEX IV MARINE ALGAE REPORTED TO OCCUR IN THE BAHAMAS
ANNEX V SEA SURFACE TEMPERATURES IN THE WESTERN ATLANTIC
REPORT ON CONSULTANCY
TO THE BAHAMAS FISHERIES TRAINING AND DEVELOPMENT PROJECT (BHA/78/001)
THE MARINE PLANT RESOURCES
AQUACULTURE POTENTIAL IN THE BAHAMAS
JAMES A. DEBOER, ASSOCIATE
GLUDE AQUACULTURE CONSULTANTS, INC.
The Government of the Commonwealth of the Bahamas, in cooperation with the United Nations Development Programme (UNDP) authorized an investigation of the potential for aquaculture in the Bahamas. The initial study, conducted by Glude Aquaculture Consultants, Inc., was completed in February, 1981. The present project is a second, short term consultancy authorized by the current cooperative project (BHA/78/001) to investigate the feasibility of utilizing seaweed resources in the Bahamas with the following terms of reference:
To carry out a survey of commercially important natural seaweed resources available in the Bahamas
To analyze the potential for harvesting wild stocks considering logistics, labour, species and quantities available, markets, harvesting and shipping costs, etc.
To study the possibility of transplanting from neighbouring countries new commercially valuable species suitable to the Bahamian waters and environments
To recommend suitable species, sites and test methods, equipment and facilities to develop seaweed culture in the Bahamas, if the above results are favourable.
An abbreviated (three week) study was conducted during the month of July 1981 and the findings and recommendations are contained in this report.
Algae are the primary productivity base for almost all natural food chains. Likewise, algae are indispensable in most types of aquaculture. In addition to serving as food, algae also recycle organic and inorganic waste materials and produce oxygen. Many algae, especially marine macroalgae (seaweeds), are utilized directly by man to provide a valuable source of human and livestock food. Seaweeds are also used as crop manure, soil conditioners and raw material for many chemicals (Chapman and Chapman 1980, Levring et al 1971, Naylor 1976).
In recent years, seaweeds have been used in the Western World primarily for their phycocolloids (alginates, a gar, and carrageenan). Agar and carrageenan, cell wall polysaccharides produced by various red algal species, are widely used in food, pharmaceutical, textile, cosmetic and other industries as suspending, thickening, stabilizing, and emulsifying agents (Mathieson 1975, Silverthorne and Sorenson 1971). The principal source of agar has been Gelidium spp., which is harvested in Japan where the agar is extracted and exported to the rest of the world. Carrageenophytes have been harvested from natural populations throughout the world, dried, and shipped to factories in North America or Western Europe, where the phycocolloid is extracted and refined for sale. Most of the world's supply of carrageenan comes from Chondrus crispus (Irish moss) populations in Eastern Canada and to a lesser extent New England and Northern Europe.
These seaweed resources are limited in area and are now heavily exploited. At the same time, the demand for phycocolloids is steadily increasing (Moss 1977). The discovery that different algal species or blends of phycocolloids from different algal species have dissimilar gelling or emulsifying properties has led to a large number of new applications of these products. These factors together have led to a screening of various species and world-wide surveys of seaweed resources by the industry over the past two decades, in an attempt to expand the base of its operation. One example of such expansion is the relatively new exploitation of the red alga Eucheuma in the Philippines and other parts of Southeast Asia. These resources, old and new, are decreasing due to overharvesting (Blanco 1972, Suto 1974, Doty 1974), pollution (Ozazaki 1971, Suto 1974, Wildman 1974) and storm damage (Parker 1974) to the extent that the industry is resource limited. Attention has become focused on cultivation as the only long-term solution.
To supplement insufficient natural supplies of agarophytes, the Japanese initiated a seaweed cultivation program several decades ago. One method involved scattering small fragments of Gelidium or Gracilaria (Lin 1970) in bays where the plants were allowed to regenerate vegetatively. More recently the Japanese have propagated Gracilaria and Gelidium (MacFarlane 1968) on ropes in shallow bays. Gracilaria culture in Taiwan (Shang 1976) has undergone a rapid expansion since its initiation in 1962. The unattached Gracilaria plants are grown in shallow ponds of approximately 1 hectare, which formerly were used for milkfish culture.
Eucheuma farming (Doty 1973, 1977, Doty and Alvarez 1975, Parker 1974, Braud 1978, Deveau and Castle 1979, and Neish 1979), developed in the Philippines, utilizes a net-culture technique that is similar to the cultivation methods used for edible seaweeds in Japan. New types of Eucheuma farming in the Philippines, utilizing monolines, cage culture and hollow planting, have achieved great success (Moss 1977, Deveau and Castle 1976).
Seaweed mariculture in Taiwan, the Philippines and other areas has become an extremely profitable enterprise attracting workers away from agriculture and other types of aquaculture. No commercial seaweed cultivation farms exist in the Americas, but several research projects involving the cultivation of red algae have evolved in the past decade (DeBoer 1978, DeBoer and Ryther 1977, DeBoer et al 1978, Lapointe et al 1976, Edelstein et al 1976, Goldstein 1973, Jamison and Beswick 1972).
A recent review of the seaweed extraction industry (Moss 1977) indicated a rapidly expanding industry if a steady supply of raw materials (seaweeds) is available. This increasing demand can be met only through aquacultural production such as the Eucheuma farms in the Philippines and Gracilaria farms in Taiwan.
The seaweed industry has experienced numerous problems as a result of the single nation monopoly of farmed Eucheuma (Doty 1977). In order to assure a reliable supply and stabilize the price of raw seaweed, farms must be developed in several countries in more than one geographical area to provide competition which will benefit both the industry and the consumer. Recent wholesale prices of dried seaseeds are shown in Table 1.
|Table 1. Purchasing prices for alginate, carrageenan and agar bearing weeds|
|Species||Moisture content||Phycocolloid||Price (US$) per ton*|
|Eucheuma cottonii||30%||K carrageenan||350|
|Eucheuma spinosum||30%||I carrageenan||300|
* FOB source, price per metric ton
Reference: C. Siletti, June 1981, personal communication
Despite close proximity to the major phycocolloid processing facilities in the U.S. and Europe, there have been few attempts to expand seaweed utilization and initiate seaweed farming in the Caribbean. Eucheuma spp. and Gracilaria spp. are harvested in Antigua, Anagada, Barbuda, Barbados, Belize, Jamaica, St. Lucia, Trinidad and other countries where the plants are used to make a “sea moss” drink or pudding. The dried plants retail for US$4.20 to 12.75 per kg in local markets. Some seaweed is exported to other Caribbean countries and to some Western countries. Although of considerable importance in some regions, the total harvest of Eucheuma and Gracilaria from the Caribbean probably does not exceed 5 to 8 tons per year.
As a result of field studies of Florida populations of Eucheuma isiforme (Dawes 1974, Dawes et al. 1974, Mathieson and Dawes 1974), two Eucheuma cultivation studies were initiated: one in the Florida Keys and one in Belize. The Belize project was initiated by an American citizen apparently with aid from the Caribbean Development Bank. He set up Eucheuma test plots at two locations but the project was terminated after only six months due to personal problems. The project was resumed by personnel of the Belize Fisheries Unit and continued for one year. In both instances incomplete records were maintained so it is difficult to extract any meaningful information from the data except that the plants survived and grew. The individual in charge of the project believed that there was good potential for Eucheuma farming in Belize (R. Kern, personal communication). A second Eucheuma farm was initiated in June 1978 by Copenhagen Pectin Factory of Denmark. The results of that project are not available but the farm was believed to have been damaged by a hurricane in the summer of 1978.
Marine Colloids Inc., stimulated by its success with Eucheuma cultivation in the Philippines, initiated a Eucheuma cultivation project in late summer 1974 in the Florida keys (Deveau and Castle 1976). Eucheuma isiforme was collected locally and grown unattached in large tanks. “Moderate” growth was attained but the tank culture method was deemed unprofitable for Eucheuma.
DeBoer initiated a small scale Eucheuma isiforme project on St. Croix in 1979. The plants survived and grew at moderate rates (0.5% to 3%/day) for at least one year. The current status of that farm is unknown as a result of the closure of the University of Texas Artificial Upwelling Project facilities on St. Croix.
Taylor (1972) recognized 760 species as occurring in the eastern tropical and subtropical coasts of the Americas. Of these, 286 have been reported from the Bahamas (Annex IV). There have been relatively few phycological surveys of the Bahamas, the most comprehensive of which were Collins (1902), Dolley (1889), Howe (1904a, 1904b, 1905, 1920, 1924) and Newell et al. (1959). Presumably additional species of seaweeds may have gone unnoticed by these investigators. During the present study, approximately 50 species of seaweeds were collected, one of which was previously unreported for the Bahamas.
Michanek (1975), in a study sponsored by the Food and Agriculture Organization fo the United Nations, investigated world wide seaweed resources through an extensive literature survey and questionnaires. He concluded that the Western Central Atlantic area, indluding the Bahamas, was “not rich in coastal seaweeds and there is presently no significant harvest”. He noted that red and brown algae did occur in commercial quantities in some locations and that a large standing stock of floating Sargassum perhaps could be harvested in amounts of a million metric tons or more.
Gracilaria spp. and Eucheuma spp., which are consumed directly and used for phycocolloid extraction, are currently the most valuable tropical red algae. Neither of these species are known to occur in quantities necessary to sustain a significant export trade from the Bahamas. None of the green algae which occur in the Bahamas has an economic value which would warrant commercial exploitation. Sargassum natans and S. fluitans (‘gulf weed’ or ‘sargassum weed’), brown algae which occur as large drifting populations in the Sargasso Sea and surrounding areas, contain low amounts of good quality alginic acid which can be utilized industrially (Davis 1950, Chapman and Chapman 1980).
With the possible exception of Sargassum spp. there do not appear to be significant amounts of seaweeds having a sufficient economic value to warrant a commercial interest at the present time. In the future, however, new processing techniques and new applications could enhance the prospects for harvesting natural seaweed populations in the Bahamas.
Most of the farming methods now employed so successfully in the Philippines, Taiwan and other countries for the cultivation of Eucheuma and Gracilaria were developed during the 1960's and 1970's. There are basically three methods in current use: net, monoline, and pond. In the net method small thalli are tied at the intersections of nylon monofilament nets. Each net is constructed of 80 lb test for the meshwork and 100 lb test for the border. The 25cm square meshwork runs diagonally within the 2.5 by 5m outline, giving 127 planting sites per net. One net requires ca. 13kg of fresh seaweed as an inoculum. The nets are suspended off the bottom using wooden stakes in water less than 2m in depth or by bouy lines in deeper water.
In the monoline system, thalli are tied every 0.2m along a 10m, 200lb test nylon monofilament line, supported by wooden stakes approximately 25cm off the bottom. The lines are spaced at 0.5m intervals, giving a planting density of 100,000 plants per hectare. Although initially developed for Eucheuma culture, both the net and monoline techniques have been used successfully for Gracilaria culture.
The pond culture method was initially developed for Gracilaria culture in the Philippines (Shang 1976). The unattached plants are grown in shallow 1ha ponds. In some ponds, grass shrimp (Penaeus mondon) and crabs (Scylla serrata) were reared together with Gracilaria to keep the plants clean and to provide additional income. The ponds were fertilized regularly with livestock manure to increase yields. Eucheuma has been cultivated in Hawaii using the pond culture method with very encouraging results (Anon. 1978).
Because annual growth data for Caribbean Gracilaria and Eucheuma populations are not available, other criteria for evaluating growth potential must be considered. Dawes (1974), Dawes et al. 1974, and Mathieson and Dawes (1974) have studied natural populations and cultivation of Eucheuma isiforme in Florida. Ryther and his colleagues at the Woods Hole Oceanographic Intitution and Harbor Branch Laboratory (Ryther et al 1979, DeBoer and Ryther 1977, and Lapointe et al 1976) have studied the aquaculture potential of Gracilaria spp. in tanks, raceways and ponds.
Although considerable data exist on the growth potential of these economically valuable seaweeds in a few locations, there are few guidelines available to predict their growth rates in new locations. Some general criteria which can be utilized to evaluate the potential for successful open coastal Eucheuma cultivation are given in Table 2. These criteria are based primarily on the empirical studies discussed above.
|Table 2. Cultivation requirements of Eucheuma spp.|
|WATER FLOW||0.2–2.0 knots but in areas protected from storm damage by offshore reefs|
|WATER DEPTH||0.5–1.75m above mean low water (shallow water culture) or up to 20m if offshore culture methods are used|
|WATER TEMPERATURE||18–33°C maximal annual variation|
26–30°C optimum growth range
|NUTRIENTS||High in phosphorus, nitrogen and iron|
|HERBIVORES||Absent or low abundance|
|SOLAR RADIATION||High (absence of frequent fog or cloudiness)|
|ENVIRONMENTAL FLUCTUATION||Minimum variation in environmental conditions|
Good water exchange is necessary to replenish nutrients used by the seaweeds, remove metabolic wastes and maintain proper water temperatures. Water depths for shallow water culture or pond culture must be sufficiently deep to cover the plants at low tide yet shallow enough to permit sunlight penetration, and ease in harvesting. In offshore culture, the depth is limited only by economic considerations of facilities and harvesting methods. Eucheuma is a tropical taxa growing best in constantly warm (26–30°C) water. It can withstand some temperature variations outside this range with reduced growth rate. Eucheuma is a stenohaline taxa requiring full salinity sea-water devoid of significant freshwater imput. As with most marine algae, phosphorus, nitrogen and possibly iron are frequently present in low concentrations resulting in decreased growth rate unless the plants are fertilized artificially. In severe storms natural populations of Eucheuma frequently break loose from their substrate. Likewise, cultivated Eucheuma or the nets or lines on which it is cultivated may break loose during severe weather. In a few farm site locations hervivorous sea urchins have consumed a portion of the seaweed production. If these sea urchins are very numerous then off-bottom cultivation techniques should be employed.
The environmental requirements for successful Gracilaria cultivation are similar to those of Eucheuma except that Gracilaria can withstand wider variations in temperature and salinity. Gracilaria can tolerate temperatures in the range of 8 to 35°C and salinities in the range of 5 to 40 ‰ for short durations without severe adverse consequences.
The techniques employed by a Philippine Eucheuma cottonii farmer will be used to exemplify seaweed farming practices. A typical farmer, assisted by two family members, will operate a ½ha farm. His work effort is approximately half time. The farm is constructed using either the net or monoline method (section 4.2). In most instances the monoline method is employed because it reduces maintenance to a minimum. With the monoline technique maintenance consists of replacing damaged lines, poles or plants, and fertilizing if necessary. Harvesting commences when the 100g seed stock pieces have grown to 3kg, a period of approximately 90 days. The plants are harvested by hand, leaving a 200g portion of the thalli remaining as seed stock. The harvested plants are transported to land and sun dried. There is approximately a five fold reduction in weight during the drying process. The dried plants are bagged or bailed and stored until sufficient quantities are obtained for shipment via containerized freight to processing plants in the U.S. or Europe.
The successful Eucheuma cottonii farms in the Philippines began as early as 1966 through a cooperative effort of the University of Hawaii and Marine Colloids, Inc. Much of the funding was provided by the U.S. Sea Grant. That project evolved from experimental test plots to demonstration farms to commercial farms. The initial “estate farms” appealed to the farmers because the sponsor (Marine Colloids) provided training programs, free loan of nets and guarantees to purchase the entire seaweed crops. Some estate farms still exist, whereas others are private farms, company farms or cooperative farms. In the case of private farms, the farmers sell their crop to a middle man who packages, stores, and arranges the shipment to the processing company.
Farm management in pond culture systems differs somewhat from the net or monoline methods. The ponds are initially stocked with the unattached seed stock and, frequently, with shrimp, fish and/or crabs to reduce algal epiphytes. A portion of the water is exchanged with each tidal cycle. Every week to ten days the ponds are fertilized after the condition of the plants has been ascertained. When the biomass of the ponds reaches some predetermined empirical value (approximately 4kg/m2) harvesting is undertaken using pitch forks or nets. The plants are then dried and stored for shipment.
When the total seaweed production from a particular geographical region is sufficient, it becomes feasible to consider constructing a processing plant in that area. Moss (1977) calculated that 1,200 to 2,300 tons of dried weed is necessary for profitable carrageenan extraction plant operation, whereas only 375 to 625 tons of dried agarophytes are necessary for an agar extraction plant. A new “preprocessing” technique is now used at several locations including the Philippines. A crude grade of carrageenan is produced by these extraction plants which can be used as is in some applications or can be further refined. The advantage of these new plants is that they require much less sophisticated equipment and therefore small plants can be economical to operate. This results in additional revenue and employment in the areas of seaweed farms.
Silverthorne and Sorensen (1971) reviewed the economics of seaweed utilization. Although the study is outdated now it contains valuable resource information. The economics of Eucheuma cottonii farming was reviewed by Deveau and Castle (1976). Assuming a 0.5ha owner operated line-type farm located in the southern Philippines with assistance from 2 or 3 family members, 2.25 tons of dried Eucheuma can be produced. A summary of the economics is shown in Table 3.
|Table 3. Small Eucheuma farm income and expenses|
2.25 tons at US$172/ton
|Net income (first quarter only)||295|
After Deveau and Castle 1976
This would yield an annual net income (early 1970) of approximately US$ 1360. The average annual family income in the Philippines at that time was approximately US$ 400. Since that time prodution yields have increased to 30 tons per hectare per year (Doty 1979), which would extrapolate to a net income of over US$ 9000 per year. It should be noted that the production of 15 tons saleable Eucheuma from a 0.5 ha farm would mean harvesting and drying 50 tons or so of fresh Eucheuma. This would entail more than part time work or one man and two or three additional family members.
Shang (1976) reported on the economics of Gracilaria pond culture in Taiwan (Tables 4 and 5).
|Table 4. Estimated initial capital cost per hectare in the culture of Gracilaria (Taiwan)|
|Well, motor and pump||1200|
|Table 5. Costs and returns of Gracilaria monoculture (per hectare)|
Harvesting and drying
|Depreciation (derived from Table 4)||134||9.7|
|Tax and maintenance||125||9.0|
|RATE OF RETURN ON INITIAL INVESTMENT||56%|
|PROFIT PER DOLLAR OF OPERATING COST||0.99|
Once again the study is somewhat out of date as a result of changes in the purchase price of the plants (increase from $275 to $800/ton), rate of production (from 10 tons to approximately 15 tons per hectare per year) and the rate of inflation. This study is particularly useful because it calculates the percentage of time spent in each activity. It should be pointed out that the labor cost for management does not reflect a full time effort for six months. Presumably, one person could manage several hectares of ponds. Gracilaria polyculture systems in which shrimp, crabs or fin fish are grown in with the plants increase the return on the investment to 98% but lower the profit per dollar of operating cost to 0.39.
It is difficult to accurately predict the magnitude of profits which could be realized from Gracilaria or Eucheuma farming in the Bahamas. Profit would be dependent on the annual rate of production of the plants, price paid for the product, labor costs, management costs, capital investment, fertilizer cost, etc. Potential economic yields for seaweed farming in the Bahamas are discussed in section 6.
As noted in section 3, the Bahamas does not have a rich flora of coastal seaweeds. The diversity and productivity of seaweeds can be controlled by several factors including solar irradiation, nutrients, substrate, water movement, temperature, grazing and pollution. It is unkikely that solar irradiation, temperature, grazing or pollution significantly limit the productivity of the Bahamian flora, although winter water temperatures may exclude some tropical species and summer water temperatures may limit some temperate species. In all likelyhood, marine algal productivity and diversity in the Bahamas is limited by nutrients and secondarily, by substrate. Nutrients in Bahamian waters are especially low in nitrogenous substances (ie ammonium and nitrate). Phytoplankton productivity in the adjacent regions of the Atlantic Ocean and Caribbean Sea is likewise limited by low nitrogen concentrations. Presumably, only those species of seaweeds which are able to utilize low nitrogen concentrations are present in the Bahamas.
The substrate in Bahamian waters consists of sedimentary materials such as limestone rock, sand, or mud. Some seaweeds can attach to or in this substrate but many seaweeds are torn loose from this substrate by waves or strong currents. Therefore, lack of a suitable substrate further limits the productivity and diversity of Bahamian seaweeds. Although other conditions may be favorable, nutrient or substrate availability may exclude some species from Bahamian waters and/or limit the productivity of the existing flora.
The lack of natural substrates and nutrients is not necessarily a constraint to seaweed aquaculture. In some types of seaweed aquaculture, the plants are grown attached to ropes or nets; in other systems the plants are maintained unattached in tanks, cages or ponds (see section 4.1). In low nutrient waters, fertilizers can be applied by spraying the surface waters or adding slow release fertilizers to the water. Thus, lack of hard substrates and low nutrient waters in the Bahamas may not be serious constraints to seaweed aquaculture.
At the present time, the most valuable seaweeds are those that are consumed directly as “sea vegetables”. Among those species which naturally occur in the Bahamas, Caulerpa racemosa, Gracilaria spp., Agardhiella subulata, Eucheuma isiforme, Catanella repens and Hypnea musciformis could be farmed for export to Japan, China, Korea and the U.S. Although the export price for these sea vegetables is comparatively high (US$ 4.50 to 8.00 per kg), the market is limited and would require a substantial marketing effort to export sea vegetables in amounts exceeding a few hundred pounds of each species per annum.
The second most valuable seaweeds, those which contain the phycocolloids, alginate, carrageenan or agar, are generally in short supply (Moss 1978) and could be exported in quantities on the order of tens of tons annually. Several species of Bahamian seaweeds contain alginates including Sargassum spp., Turbinaria spp. and Cystoseira myrica, however, the purchasing price of alginate bearing weeds is low (usually less than $200 per ton) as a result of extensive kelp populations in temperate areas which can be mechanically harvested. It might be feasible to harvest Sargassum spp. in the Bahamas because some species drift in from the Sargasso Sea. At least one corporation (Aqua 10 in Beaufort, North Carolina) has been established to harvest and process Sargassum from the Sargasso Sea. This company extracts alginic acid, a soil conditioner/fertilizer and cattle feed from the seaweeds. Additional studies are needed to determine if there are natural populations of Sargassum close to the Bahamas to warrant the commercial exploitation of this species here.
The best prospect at the present time for seaweed aquaculture in the Bahamas lies in the cultivation of agarophytes and carrageenophytes (Table 6). Of these species, only Gracilaria spp., Eucheuma isiforme, and Hypnea musciformis are likely candidates for aquaculture. Gelidiella acerosa is too small and Digenia simplex has a low agar content. Agardhiella subulata has a moderate carrageenan content and size and may be amenable to pond culture. Grateloupia filicina may be suitable for cultivation after additional studies are completed.
|Table 6. Agarophytes and Carrageenophytes found in the Bahamas|
The best current prospects for seaweed aquaculture in the Bahamas lie in Gracilaria debilis, Eucheuma isiforme or imported species of these genera. Gracilaria debilis is a large (up to 25cm), bushy coarse seaweed that grows rapidly in culture. This species can be sold as a sea vegetable for up to US$ 12.75/kg or for agar at US$ 800/ton. The species ranges in distribution from Bermuda and Florida to Brazil so is likely to grow well during most of the year in Bahamian waters. Eucheuma isiforme attains heights of 50 cm or greater, forming bushy cartilaginous thalli. This species ranges from Bermuda and Florida to Venezuela. The factors which affect the productivity of this species are not well understood. In certain areas such as Barbuda, Barbados and Belize, extensive populations of this species are found. In the Bahamas, as in many other areas, production of Eucheuma is low. In culture, Eucheuma exhibited moderate growth rates in Florida. In Belize (W. Miller and R. Kern, personal communication) and St. Croix (DeBoer, unpublished) the growth rates (without supplemental fertilization) were moderate.
Different species or varieties of Gracilaria and Eucheuma from other areas of the world might be very well suited to aquaculture in the Bahamas. Some of these varieties, for example the Tambalang strain of Eucheuma cottonii, have been partially domesticated to the degree that the plants are much hardier and grow faster than natural strains.
The Bahamas lie between 72° and 80° West longitude and 21° and 28° North latitude. The 260,000km2 archipelago extends for over 800km between southeast Florida and northern Hispaniola. Some 29 islands and numerous cays emerge from the shallow water areas, totalling about 156,000km2.
Accurate records of salinity variations in Bahamian waters are not available. Except in a few very shallow areas, not suitable for seaweed aquaculture in any case, salinity would not be expected to deviate substantially from oceanic salinity (36‰) due to rapid movement of water over the Bahamas Banks, the low rate of rainfall, and the relatively low topography, minimizing drainage from land areas.
Sea surface temperatures in the Atlantic Ocean just off the Bahamas Banks are shown in Annex V. These values range from an average low temperature of 20.5°C to an average high temperature to 29.5°C. This range is not excessive for Eucheuma or Gracilaria. However, the water temperature range in shallow farming areas would undoubtedly be greater than this. As a result of the temperature variations, the growth of seaweeds in the Bahamas would probably be seasonal rather than constant throughout the year. Tropical species would be apt to excel during the summer, whereas more temperate species would be expected to grow best during the winter. Seaweeds grown in the extreme northern islands would be expected to exhibit more seasonality in growth as compared to the southern islands.
Tropical cyclones, which frequently enter the Bahamian archipelago, form in the tropical waters of the North Atlantic, Caribbean and Gulf of Mexico. They usually progress along a west or northwest course, with the path later recurving to north to northeast. Tracks of individual cyclones vary widely and are frequently difficult to predict with accuracy. The average number of tropical cyclones per year which have been centered within 166km of the Bahamas over the last 104 years is:
The term “tropical cyclone” includes hurricanes, tropical storms and tropical depressions. The frequency of tropical cyclones affecting any one part of the Bahamas is considerably less than that indicated above, and the frequency of hurricane force winds affecting one locality is much less still. For instance, hurricane force winds might be expected for Nassau once in nine years. The number of storms entering each 2½ degree area in the Bahamas as hurricanes, tropical storms or depressions is shown in Figure 1.
Figure 1. Numbers of storms passing through each 2½ degree square during the period 1886 to 1969. The figures next to H, TS, and D give the numbers of these storms which were hurricanes, tropical storms or depressions, respectively on entering these 2½ degree squares. The probability figure is the probability of at least one hurricane or tropical storm passing through the 2½ degree square in one year. Reference: Hoppe and Neuman (1971).
The selection of suitable farm sites is a complex problem which was discussed in part in section 4.4. The criteria for seaweed farm site selection are difficult to define due to a paucity of published information on the physiological ecology of economically valuable seaweeds. Therefore, there is not an “exactly defined technique whereby an area can be surveyed” for farm site selection (Deveau and Castle 1976). The only means of accurately evaluating a site at the present time is to establish test plots.
In addition to biological considerations there are a number of additional factors which also must be considered. Logical sites to locate farms would be areas in which:
As a rough indicator of farms site potential in the Bahamas, hydrographic charts were used to locate areas which possessed shallow reef areas. For the purposes of this study, only those reef areas which had water depth of 0.5 to 5.0m were considered suitable for seaweed farming. Potential shallow water farming areas have been calculated in Table 7.
The area in any geographical location actually suitable for seaweed farming is certainly considerably less than the total areas estimated in Table 7. For instance, some shallow reef areas near Andros Island are as much as 78km away from the nearest Bahamian land. Such areas would not be practical for farm development.
|Table 7. Calculation of Bahamian shallow water areas (0.5 to 5.0m above MLW)|
|Location||Shallow Reef Area|
|Little Bahama Bank||5732||573,200|
|Great Bahama Bank||75904||7,590,400|
|Bight of Acklins||523||52,300|
It has been estimated that an eventual annual shipment of at least 50 tons (Gracilaria) or 300 tons (Eucheuma) from the Bahamas would be adviseable for economic reasons (I.C. Neish, personal communication). To meet those minimum production requirements, a total of 5 to 10ha in seaweed farms would be required, assuming an annual production of 10 to 30 tons per hectare. Since the minimum area required for seaweed farming represents only one-one millionth of the shallow reef areas available it seems reasonable to assume that sufficient shallow reef areas are available in the Bahamas. In fact, there are substantially more shallow reef areas in the Bahamas than in any other area of the Caribbean. The question as to which specific areas within the Bahamian archipeligo meet this areal requirement and are also excellent seaweed growing areas is difficult to resolve.
Very little information exists on the distribution of Eucheuma and Gracilaria in the Bahamas. There is no information available on growth rates.
The criteria for political and economic stability and a low rate of crime and corruption appears to be met in the Bahamas. The frequency of tropical storms is such that they would not be a major deterrent to otherwise successful farms. Good containerized freight service is available from Nassau and Freeport. Dependable low cost labor is a criterion which is difficult to access before possible production rates can be estimated from test farm studies.
The paucity of information regarding the seaweed resources of the Bahamas makes it difficult to access the feasibility of their commercial harvest. Based on this information and observations during this study, the only seaweed present in sufficient amounts for large-scale commercial harvest would be Sargassum spp. Additional interviews, observations and market analysis would be required before commercial utilization could be considered.
Seaweed cultivation appears to be biologically and technologically feasible in the Bahamas. Even a small fraction of the more than eight million hectares of shallow reef area in the Bahamas would provide abundant space for coastal seaweed farming. Alternatively, pond culture could be undertaken in the vast low lying areas not suitable for agricultural, residential or industrial development.
Agarophytes and carrageenophytes are the most commercially valuable seaweeds for which there exists a large demand. Gracilaria spp. and Eucheuma spp. are tropical seaweeds which contain comparatively large amounts of good quality agar and carrageenan, respectively. Both genera occur in the Bahamas and are likely to grow fast enough in cultivation for commercial utilization. These two genera could be grown on lines in shallow or deep water or on shore in ponds. A commercial farm would occupy an area of approximately 0.5 to 1.0 ha if family operated or a substantially greater area if operated by a cooperative or company. The size of a farm could also be increased by mechanizing the harvesting and/or drying operations.
Presumably, the production yields from Eucheuma would be somewhat lower than in the Philippines as a result of suboptimal growing conditions at least in the northern Bahamas. It might take up to three years to select a Eucheuma strain which grows rapidly at a particular location in the Bahamas. Annual production yields of 15 to 25 tons per hectare do not seem unreasonable, once a suitable strain of Eucheuma is found.
Bahamian rates of production of Gracilaria might be comparable to those obtained in Taiwan because similar conditions exist in these locations. Hence, an annual production rate of 10 to 15 tons per hectare is a good estimate.
Assuming these production rates and current purchase prices this would mean a gross income of $5250 to $8750 for Eucheuma and $8000 to $12,000 for Gracilaria. Since the initial capital and fertilizer costs are a low percentage of the gross income, most of the gross income could be realized as wages and profit to the seaweed farmer. An increase in the size of the farm may be possible by partial mechanization of the harvesting and/or drying operations.
The dried plants produced on owner, cooperative or company farms would be baled or bagged and stored until quantities sufficient for shipment (i.e. 15 tons for containerized freight) were available. An extraction plant located in the Bahamas could be built after an initial cultivation start-up phase (i.e. after approximately 3–5 years). The ability to extract the phycocolloid in the Bahamas could vastly improve the economics of cultivation by eliminating the need to dry the plants prior to shipment. Furthermore, the extraction plant would provide additional revenues and jobs in the Bahamas.
Seaweed aquaculture has many advantages as a new industry for the Bahamas. Because it is labor intensive, seaweed aquaculture could provide substantial new employment. Very little capital investment is required so almost anyone can start farming without financial assistance. The level of technology is low which means that very little training or specialized equipment is required. Seaweed farms are usually located in areas which are not normally suitable for other uses. Finally, seaweed farms usually have a positive effect on the environment. Seaweed farms actually improve fishing in and around the farm. Many seaweed farmers locate fish traps near their seaweed farms to realize additional profits.
In the final analysis the primary task of this study was to attempt to answer the question, “Could a Bahamian make a good living farming seaweeds?”. A rough estimate of the wages and profit a Bahamian seaweed farmer (assisted by 2 family members) might make is $4000 to $10,000 per year. An ambitious farmer might be able to realize a higher profit. Buying prices of the plants fluctuate with supply and demand. Therefore, it is impossible to make any firm predictions of profit. As noted previously, profits could increase substantially for larger, mechanized farms located near a processing plant.
Another variable in this feasibility study is wages in the Bahamas. The 1978 Agricultural and Fisheries Statistics Report lists the household income for Bahamians involved in agriculture, forestry, fishing, and hunting who live on islands other than New Providence and Grand Bahama. In 1975, approximately 42% of these households had incomes less than $5000 per year. Current income levels were not available.
Earlier this year, Fisheries Development Limited issued a final report titled “The Bahamas Feasibility Study of Fishing Industry Development in Designated Economically Disadvantaged Islands”. The report recommended an artisanal fishing project which would create 237 jobs at an average annual income of B$5000, which was, they indicated, acceptable in the context of the development area. They estimated the cost of the project to be B$2,879,000.
A marine plant farming project would probably yield a comparable income and create (initially) 50 jobs at a cost of perhaps B$400,000. If successful, the program could be expanded in five years to over 200 jobs at little additional cost.
Regrettably, it was not possible to visit any of the “economically disadvantaged” islands during this abbreviated study. On the basis of interviews, public reports and hydrographic charts, it appears that the Bight of Acklins, Long Island, Great Exuma and Cat Islands might be good locations for Eucheuma farming. Gracilaria pond farming might be feasible on parts of Andros Island, Acklins Island, Crooked Island, Long Island, Cat Island or Great Exuma. One prospective area to investigate Gracilaria would be in some of the Diamond Crystal salt ponds at Long Island.
This report has indicated in a general manner the possibilities and limitations of seaweed farm development in the Bahamas. If it is decided that the possibilities warrant additional study, the following development plan for seaweed farms is recommended:
Conduct field surveys of potential farm sites. This study would include an assessment of the abundance and species of seaweeds present, water temperatures, currents, depths, salinity, nutrients, land sites for drying and/or ponds, etc.
Conduct a survey of the present status of Eucheuma and Gracilaria cultivation methodology in other areas of the world.
Initiate test plots of local and/or imported strains of Eucheuma and Gracilaria. The test plots should be small (approximately 4m2) but located in as many different areas as possible and monitored for a period of at least one year.
Demonstration farms and educational programs would be initiated in those areas where the test plots showed the greatest success.
Commercial production with partial subsidies from governmental or industrial sources.
As was suggested in Glude's February 1981 report on the feasibility of aquaculture in the Bahamas, a Regional Mariculture Centre could provide the expertise, research facilities, training and coordination capabilities, and momentum necessary for aquaculture development in the Bahamas and the Caribbean. This study confirms the importance of establishing a Regional Mariculture Centre.
|San Antonio, TX||5 July|
|Nassau, Bahamas||5 July||7 July|
|Current Island, Bahamas||7 July||8 July|
|Nassau, Bahamas||8 July||14 July|
|North Eleuthera, Bahamas||14 July||15 July|
|Nassau, Bahamas||15 July||16 July|
|Andros Island, Bahamas||16 July||17 July|
|Nassau, Bahamas||17 July||20 July|
|Grand Bahama Island, Bahamas||20 July||20 July|
|Nassau, Bahamas||20 July||25 July|
|San Antonio, TX||25 July|
|1.||FAO Fisheries Development Project, Nassau|
|Mr. Burtonboy, A., Marketing Specialist and Acting Project Leader|
|Mr. Wedderburn, J., Master Fisherman|
|2.||Government of the Bahamas, Nassau|
|Mr. Thompson, R., Director of Fisheries, Ministry of Agriculture, Fisheries and Local Government|
|Mr. Bethell, P., Deputy Director of Fisheries|
|Mr. Higgs, C., Biologist|
|Mr. Braynen, M., Fisheries Officer|
|Mr. Albury, R., Fisheries Assistant|
|Mr. Burrows, H., Fisheries Assistant|
|Mr. Tertullien, J., Director of Statistics|
|Mr. Smally, M., Director of Meterological Department|
|3.||New Providence Island|
|Mr. Lewless, J., Nassau Businessman|
|Mr. Isaacs, S.A.O., Lawyer for Morton Bahamas, Ltd.|
|4.||Grand Bahamas Island|
|Dr. Bizzell, P. President Bahamas Mariculture Research Inst.|
|Ms. Woon, G., Biologist, Wallace Groves Aquaculture Foundation|
|Mr. Waugh, G., Biologist, Wallace Groves Aquaculture Foundation|
|Mr. Smith, C., Fisherman and resort owner|
|Mr. Smith, N., Fisherman|
|6.||Spanish Wells, Eleuthera Island|
|Mr. Higgs, G., Fisherman|
|Mr. Pinder, W., Fisherman|
|Mr. Pinder, B., Fisherman|
|Mr. Pinder, L., Businessman|
Anonymous. 1976 Seaweed processing plant established in Coastal Plains region. Marine Newsletter, vol. 7(4):1.
Anonymous. 1978. Seaweed culture: Technology with no place to go? Sea Grant Newsletter, vol.8 issues 5 and 6.
Aquaculture Development and Coordination Programme. 1981. Aquaculture Development in the Caribbean, Report of a Review Mission to Antigua, Haiti, Jamaica, Montserrat and St. Lucia. United Nations Development Programme, Food and Agriculture Organization of the United Nations.
Bahamas Meterological Department. 1975. Tropical Storms and Hurricanes Affecting the Bahamas.
Blanco, G.J. 1972 Status and problems of coastal aquaculture in the Philippines. In: Pillay, T.V.R. (ed.) Coastal Aquaculture in the Indo-Pacific Region. Fishing News (Books) Ltd., London, pp. 60–67.
Braud, J.P. 1979. Farming on pilot scale of Euchema spinosum (Florideophyceae) in Djibouti Waters. Int. Seaweed Symp. 9:533–540
Chapman, V.J. and D.J. Chapman. 1980. Seaweeds and their uses. Chapman and Hall, London and New York. 334 pp.
Collins, F.S. 1902. Marine algae, pp. 12–14. In: Northrop, A.R., Flora of New Providence and Andros. Mem. Torrey Bot. Club vol. 12.
Davis, F.W. Potential products from Gulf of Sargassum weed. Proc. Gulf Carrib. Fish. Inst. 2: 102–3.
Dawes, C.J. 1974. On the mariculture of the Florida seaweed, Eucheuma isiforme. Fla. Sea Grant Program Rep. (5): 10p.
Dawes, C.J. A.C. Mathieson and D.P. Cheney. 1974. Ecological Studies of Floridean Eucheuma I. Seasonal growth and reproduction. Bull. Mar. Sci. 24: 235–273.
DeBoer, J.A. 1979. Effects of nitrogen enrichment on growth rate and phycocolloid content in Gracilaria sp. and Neoagardhiella baileyi. Int. Seaweed Symp. 9: 263–272.
DeBoer, J.A., H.J. Guigli, T.L. Israel and C.F.D'Elia. 1978. Nutritional studies of two red algae. I. Growth rate as a function of nitrogen source and concentration. J. Phycol. 14: 261–266.
DeBoer, J.A. and J.H. Ryther. 1977. Potential yields from a waste recycling-algal mariculture system, pp. 231–249. In: The Marine Plant Biomass of the Pacific Northwest: A Potential Economic Resource, R.W.Krauss(Ed.). Oregon State University Press, Corvallis.
Deveau, L.E. and J.R. Castle. 1976. The industrial development of farmed marine algae: The case history of Eucheuma in the Philippines and USA, pp. 410–416. In: Advances in Aquaculture, T.V.R. Pillay and W.A. Dill (Eds.). Fishing News (Books) Ltd., Farnham, Surrey, England.
Dolley, C.S. 1889. The botany of the Bahamas. Proc. Acad. Nat. Sci. Phila. 1889: 130–135 (1890).
Doty, M.S. 1973. Farming the red seaweed, Eucheuma, for carrageenans. Micronesica 9: 59–71
Doty, M.S. 1977. Eucheuma--Current marine agronomy, pp. 203–214. In: The Marine Plant Biomass of the Pacific Northwest: A Potential Economic Resource, R.W. Krauss (Ed.). Oregon State University Press, Corvallis.
Doty, M.S. 1979. Status of marine agronomy, with special reference to the tropics. Int. Seaweed Symp. 9:35–58.
Doty, M.S. and V.B. Alvarez. 1975. Status, problems, advances and economics of Eucheuma farms. Mar. Technol. Soc. J. 9: 30–35.
Edelstein, T.,C.J. Bird and J. McLachlan. 1976. Studies on Gracilaria. 2. Growth under green house conditions. Can. J. Bot. 54:2275–2290.
Glude, J.B. 1981. The Feasibility of Aquaculture in the Bahamas. A report to the Fisheries Training and Development Project (BHA/78/001) Nassau, Bahamas.
Goldstein, M.E. 1973. Regeneration and vegetative propagation of the agarophyte Gracilaria debilis. Bot. Marina 16:226–228.
Hoppe, J.R. and C.J. Newmann. 1971. Digitized Atlantic Tropical Cyclone Tracts. NOAA Technical Mememorandum NWS SR-55.
Howe, M.A. 1904a. Collections of marine algae from Florida and the Bahamas. J. New York Bot. Gard. 5:164–166.
Howe, M.A. 1904b. Notes on Bahamian algae. Bull. Torrey Bot. Club 31:93–100 plus plates.
Howe, M.A. 1905. Phycological studies. I. New Chlorophyceae from Florida and the Bahamas. Bull. Torrey Bot. Club 32:241–252.
Howe, M.A. 1924. Notes on algae of Bermuda and the Bahamas. Bull. Torrey Bot. Club 51:351–359 plus figures
Lapointe, B.E., L.D. Williams, J.C. Goldman, and J.H. Ryther. 1976. The mass outdoor culture of macroscopic marine algae. Aquaculture 8:9–21.
Levring, T., H.A. Hoppe, and O.J. Schmid. 1966. Marine Algae: A Survey of Research and Utilization. Cram, De Gruyter and Co. Hamburg
Lin, M.N. 1970. The production of Gracilaria in Yuanchang Reservoir, Putai, Chiayi. Reports of Fish Culture. Chinese-American Joint Committee on Rural Resonstruction Fisheries Series No. 9, pp. 30–34.
MacFarlane, C.I. 1968. The Cultivation of Seaweeds in Japan and Its Possible Application in the Atlantic Provinces of Canada. Canadian Department of Fisheries, Ind. Dev. Serv., Ottawa. 96pp.
Mathieson, A.C. 1975. Seaweed aquaculture. Mar. Fish. Rev. 37: 2–14.
Mathieson, A.C. and C.J. Dawes. 1974. Ecological studies of Floridean Eucheuma. II. Photosynthesis and respiration. Bull. Mar. Sci. 24:274–285.
Michanek,G. 1975. Seaweed Resources of the Ocean. FAO Fisheries Technical Paper No. 138, 127pp.
Moss, J.R. 1977. Essential considerations for establishing seaweed extraction factories,pp. 301–314. In: The Marine Plant Biomass of the Pacific Northwest: A Potential Economic Resource, R.W. Krauss (Ed.) Oregon State University Press, Corvallis.
Naylor, J. 1976. Production, Trade and Utilization of Seaweeds and Seaweed Products. FAO Fisheries Technical Paper No. 159, 73pp.
Neish, I.C. 1976. Developments in the culture of algae and seaweeds and the future of the industry, pp. 395–402. In: Advances in Aquaculture, T.V.R. Pillay and W.A. Dill (Eds.). Fishing News (Books) Ltd. Farnham, Surrey, England.
Okazaki, A. 1971. Seaweeds and Their Uses in Japan. Tokai University Press, Tokyo. 165pp.
Parker, H.S. 1974. The culture of the red alga genus Eucheuma in the Philippines. Aquaculture 3:425–439.
Shang, Y.C. 1976. Economic aspects of Gracilaria culture in Taiwan. Aquaculture 8:1–17.
Silverthorne, W. and P.E. Sorenson. 1971. Marine algae as an economic resource. Mar. Technol. Soc. Ann. Conf. 7:523–533.
Suto, A. 1974. Mariculture of seaweeds and its problems in Japan, pp. 7–16. In: Proceedings, First US--Japan Meeting on Aquaculture, W.N. Shaw (Ed.). NOAA Tech. Rep. NMFS CIRC-388.
Taylor, W.R. 1929. Notes on algae from the tropical Atlantic Ocean I. Amer. Jour. Bot. 16:621–630 plus plates and figures.
Taylor, W.R. 1941. Tropical marine algae of the Arthur Schott Herbarium. Field Mus. Nat. Hist. Pub. 509 Bot. Ser. 20(4):87–104.
Waaland, J.R. 1973. Experimental studies on the marine algae Iridaea and Gigartina. J. exp. mar. Biol. Ecol. 11:71–80.
Wildman, R. 1974. Seaweed culture in Japan, pp. 97–101. In: Proceedings, First US-Japan Meeting on Aquaculture, W.N. Shaw (Ed.). NOAA Tech. Rep. NMFS CIRC-388, pp. 97–101.
# *Cryptonemia luxurians
* Collected during this study
# Previously unreported for the Bahamas
Source: U.S. Hydrographic Office. 1967. Oceanographic Atlas of the North Atlantic Ocean Pub. #700. Section II. Physical Properties.
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