the fish

from http://www.thefishsite.com

The organic label remains elusive in today's world of aquaculture, but never has there been a time when its application has been so necessary. Just as the organic movement in livestock was borne from a public response to the damaging and unethical aspects of intensification, now the same concerns have come to bare upon the aquaculture industry.

The rapid aquaculture boom lies at the root of these unsustainable practises. Rather than being hailed as the saviour of wild fish populations, a large amount of research has focused on the negative impacts of fish farms. In order for the consumer to embrace aquaculture, aquaculture must first embrace scientific solutions.

There are two trends that highlight the necessity for a sustainable future in aquaculture. One, is the rapidly increasing global levels of fish demand, and the other is the rapidly decreasing population of wild fish stock. If the future supply of fish cannot be sustained there will simply not be enough left to eat.

But there are other benefits also. The Center for Food Safety (CFS) a non-profit, membership organisation that works to protect human health and the environment, says that by applying the true holistic approach of organic system management to aquaculture could yield "significant reductions in the documented negative environmental and health impacts of industrial aquaculture". When these practices are acknowledged it gives the organic product market power, and with it, the potential to increase the value of its product and of the industry as a whole.

According to a United States Department of Agriculture (USDA) report, the market potential for organic aquaculture seems to be promising in Europe as well as in the USA. Production takes place primarily in Europe, where certified organic salmon, carp, and trout are grown and sold. Certified organic mussels, Tiger shrimp, white shrimp, and tilapia also are cultured in such diverse places as Vietnam, Peru, Ecuador, Chile, New Zealand, and Israel.

However, creating a set of universally accepted organic standards has proven difficult in aquaculture. In many ways, this ambiguity alone has prevented the movement from flourishing.

How Organic is Organic?

Due to the stringent nature of organic practices for food animals and crops, many people believe organic aquaculture is an unattainable prospect for the industry. Whilst those that believe it can be workable tend to disagree on how.

In 2002 the Food and Agriculture Organization (FAO) claimed that there were 20-25 private and non-private certifying bodies for organic aquaculture, varying from from country to country, certifier to certifier, and species to species. In a bid to unify these labels the International Federation of Organic Agriculture Movements (IFOAM) has attempted to create guidelines that will hormonise organic production and certification worldwide.

Likewise, a new European organic regulation will have detailed aquaculture rules for the first time and is planned to be launched in January 2009. This will then form the legal basis for organic aquaculture in Europe.

The variety of species produced in aquacultural systems and vast differences in cultural requirements for finfish, shellfish, mollusks, and aquatic plants add to the complexity of defining this sector. Some species and some production systems proving more difficult than others to adapt to a traditional “organic” system.

Salmon farming in open water pens are a challenge for organic production due to escapes, sea lice contamination and nutrient losses.

According to a spokesperson for the Soil Association: "It is certainly a different prospect to think of the aquatic environment rather than the traditional 'soil' based approach of organic agriculture but the overarching organic principles as defined by IFOAM can still be applied to farming in water."

"You have to bear in mind that terrestrial agriculture is the most environmentally destructive activity the human race has ever undertaken", the spokesperson continued, adding: "There are aquaculture systems such as shellfish farming which are much more sustainable and organic than almost all terrestrial farming systems."

The Soil Association says that pond grown species such as carp, tilapia, catfish and similar species can be grown at low stocking densities with minimal external feed requirements.

However, the Soil Association also says that the use of fishmeal and fish oil in aquaculture feeds, particularly in diets for carnivorous fish, has been criticised as inherently unsustainable, and a source of persistent organic pollutants (such as PCBs and dioxins).

The aquaculture industry consumes approximately 46 per cent and 81 per cent of the global supply of fishmeal and fish oil respectively. Furthermore, the huge complexity of global marine fisheries makes the sustainable use of fishmeal and oil one of the greatest challenges facing not just organic producers, but the whole aquaculture industry.

A New Label

Organic Labels offer consumers a trusted commercial option that presents solutions to these problems, but what happens when this trust is broken?

* "This is a delicate balance between organic principles and commercial development"

Soil Association spokesperson.

Recently the National Organic Standards Board (NOSB), an advisory panel to the USDA's Agricultural Marketing Service has come under fire for approving relaxed standards for the organic aquaculture label. Under the new proposal farmed fish will be labelled 'organic' even if their diets include wild fish and other feed that isn’t organic itself. The proposal allows up to a quarter of farmed fish feed to consist of wild fish, though not from endangered species.

A news item released from the Washington Post claimed that the rules would also: "allow farmers to raise the fish in open-net cages, which rankles environmentalists concerned about the spread of sea lice into nearby waterways". A trend, the newspaper added, "that could drive wild salmon to extinction".

The concern is that if this proposal is enacted, the organic standards will not only allow sub-par organic fish to be sold with a premium, but will undermine consumer confidence in the entire organic marketplace.

In a recent report, the Centre for Food Safety said that it had serious issues with the proposals, adding that they will fatally undercut any future organic aquaculture standard and are inconsistent with organic principles.

"One of the most basic steps in changing our approach to fish farming is changing our mindset towards it."

But there’s big money to be made in salmon farming — all the more if your fish sell for the premiums that official USDA organic certification confers.

The Soil Association said that there is a risk of devaluing the organic label if certain regulatory bodies and certifiers use weaker standards. "This is a delicate balance between organic principles and commercial development," the association said.

from http://www.thefishsite.com

Most are found within latitude 25° north and south of equator, covering approximately 17 million ha (Aizpuru et al, 2000) in 112 countries and territories in Asia, Africa, Australia, and the Americas.

Global estimates of mangrove coverage vary considerably, for example, according to FAO there were 15.2 million ha as at 2005 (FAO, 2007). Close to half of mangrove coverage occurs in five countries, i.e. Indonesia, Australia, Brazil, Nigeria and Mexico. Mangroves are unique as they occupy an ecotone between land and sea, where the environment is distinctly different from marine and terrestrial environs.

Global extent of mangroves (FAO 2004)

At present, south east Asia harbours the largest extent of mangroves on Earth, i.e. 4.9 million ha or nearly 35 per cent of the world’s total, with coverage along the coasts of Brunei Darussalam (0.3 per cent of total south east Asian area), Cambodia (1.3 per cent), Indonesia (59.8 per cent), Malaysia (11.7 per cent), Myanmar (8.8 per cent), Papua New Guinea (8.7 per cent), Philippines (2.2 per cent), Singapore (0.01 per cent), Thailand (5.0 per cent), Timor-Leste (0.03 per cent), and Vietnam (2.1 per cent) (Giesen et al, 2006).

The largest mangrove areas in south east Asia therefore occur in Indonesia. In general, the mangroves of south east Asia are the best developed and most diverse in terms of plants and animals. Fifty two out of the 268 plant species that have been recorded from these mangrove areas are true mangrove species or those that are found only in mangrove habitats while the others are mangrove associated species that are also encountered in non-mangrove habitats. Eighteen species of mangrove plants are endemic to the south east Asian region and eight out of them are true mangroves (Giesen & Wulffraat, 1998).

Mangrove habitat

Inter-tidal areas with accumulated river-borne sediment due to the sheltered nature of the locality from wave action are the ideal habitats to be colonised by mangrove plants. Although it was believed initially that mangroves trap sediment, the current consensus is that mangroves consolidate the sediment that has been deposited through flocculation (Chapman, 1977).

Tidal action is a primary factor that determines mangrove ecology, i.e. ecosystem processes. Mangrove habitats are inundated with tides, either daily or a few days a month (spring tides) and thus the sediment is saline. Greater soil salinities occur in dry coastal areas where rainfall is insufficient to flush off salt from soil periodically. Inundation leads to anaerobic soil environments where oxygen is scarce for plant root systems. The soils are unstable due to tidal movement of water and therefore are unfavourable to support plants. Freshwater is a scare resource in mangrove habitats and hence conditions are not conducive for seed germination.

Extent and distribution of mangroves in study areas of MANGROVE project

The MANGROVE project aims to develop strategies to reconcile multiple demands on mangrove resources. The project is focussing on areas of Mahakam delta in East Kalimantan, Indonesia; the Province of Nakhon Si Thammarat in southern Thailand; and Tien Hai district of Thai Binh Province in Red River Delta in Vietnam. These sites have been selected as representative areas characterised by conflicting interests in terms of management, governance and use of mangrove resources that have led to significant decline in mangrove extents.

Indonesia

Indonesian mangroves comprise nearly 22 per cent of the global total or 60 per cent of the mangroves in south east Asia, with some 3.5 million ha distributed along sheltered coasts of Sumatra (over 570,000 ha), Kalimanthan (1,139,460 ha), Java (33,800 ha), Sulawesi (about 256,800 ha), Lesser Sundas (15,400 ha), Moluccas (148,710 ha) and Iriyan Jaya (1,326,990 ha) (Wilkie and Fortuna, 2003).

In Kalimantan, which harbours 32.6 per cent of all Indonesian mangroves, the least disturbed areas are mostly restricted to West Kalimantan where 15,000 ha are protected in Gunung Palung National Park, Muara Kendawangan Wildlife Reserve and Tanjung Puting National Park. (Giesen et al, 2006). The largest mangrove area in East Kalimantan occurs in the delta of Mahakam River, which is the study site of MANGROVE project in Indonesia. These mangroves have either been logged or disturbed by other land uses such as drilling for oil and gas, shrimp farming, development of ports and human settlements. (Refer Situation of the mangrove ecosystem and the related community livelihoods in Muara Badak, Mahakam Delta, East Kalimantan, Indonesia).

Thailand

The total extent of mangrove areas in Thailand also lacks consensus. According to Wilkie and Fortuna, 2003, from 1973 to 2000 mangroves of Thailand have dwindled from 312,732 to 244,085 ha while Charupat and Charupat (1997) recorded a decline from 372,448 ha in 1961 to 167,582 ha in 1996. The Department of Marine and Coastal Resource (DMCR), estimates the total extent of mangroves in Thailand to be 233,700 ha in 2004. (Refer Multidisciplinary situation appraisal of mangrove ecosystems in Thailand.

Mangroves are distributed on the coasts of Indian Ocean and Gulf of Thailand. The largest remaining mangrove areas occur on the coastal areas of the Indian Ocean and they are found in Phang Nga (45,500 ha), Satun (35,300 ha), Krabi (35,000 ha), Trang (33,500 ha) and Ranong (25,300 ha) provinces (Giesen et al, 2006).

Being an estuarine complex with a sheltered coast to which four major rivers, the Mae Klong, Tachin, Chao Phraya and Bang Pakong discharge freshwater, the Gulf of Thailand is the ideal habitat for mangroves. In the past, it has supported extensive areas of mangroves which have subsequently been cleared for aquaculture, salt pans and human settlements. Currently, mangroves of Gulf of Thailand are restricted to a narrow (10 – 100 m) fringe along the coast (Giesen et al, 2006). The study site of MANGROVE Project in Thailand is in the Province of Nakhon Si Thammarat, which borders Gulf of Thailand.

The coast of Andaman sea (Indian Ocean) supports 75 per cent of mangroves in Thailand which accounts for 174,335 ha while the extent around Gulf of Thailand is relatively low, covering only 59,365 ha (DMCR unpublished records). The southern part of Gulf of Thailand harbours 12 per cent of the remaining mangroves in Gulf of Thailand and only 4.4 per cent or 10,278 ha are located in Nakhon Si Thammarat.

Vietnam

The largest extent of mangroves occurs in southern Vietnam associated with Dong Nai and the Mekong River estuaries, with over 191,800 ha while the second largest extent, i.e. 39,400 ha lies in the north eastern Quang Ninh Province followed by those in the estuaries of Thai Binh and Hong (Red) rivers, 7,000 ha in the northern part of Vietnam. The coastal areas in central part of Vietnam supports the least (3,000 ha) extent of mangroves (Giesen et al, 2006). The total extent of mangroves has been estimated to be 252,500 ha in 1983 (FAO, 2004).

Xuan Thuy Wetland Reserve in Red river delta is the study site of MANGROVE project and it has been declared as a RAMSAR site in 1988. This is the largest remaining mangrove area in the Red River Delta.

Changing mangrove extent and causes

Available data on changing global extents of mangroves also manifest a lack of consensus, although they do indicate common trajectories of change.

During the past 25 years, 3.6 million hectares of mangroves or approximately 20 per cent of the total extent found in 1980, have disappeared from the Earth’s surface. Conservative estimates indicate that on a global scale, mangroves decline by 1,000 km2 annually. The rate of net loss of mangroves however show a decreasing propensity, from 1.03 per cent loss per annum in 1980 to 0.67 per cent annual loss during 2000–2005 period. This is attributed to increased awareness of the value of mangrove ecosystems, which has led, in turn, to the preparation of new legislation, better protection and management and, in some countries, to an expansion of mangrove areas through active planting or natural regeneration (FAO, 2007).

Results of a trend analysis published in the Forest Resources assessment Working Paper-063 (of FAO (2004)) indicate that the current mangrove area worldwide has now fallen below 15 million hectares, down from 19.8 million ha in 1980. The world has thus lost 5 million ha of mangroves over the last twenty years, or 25 percent of the extent found in 1980.

Indonesia

Shrimp farming evidently is the cause of approximately 25 per cent loss of mangroves in Indonesia while conversion to agricultural, mainly paddy land, over-exploitation by coastal communities, commercial logging and lack of effort on regeneration of degraded and over-exploited mangrove areas have been identified the reasons for 75 per cent of the mangrove loss (Giesen et al, 2006).

Commercial logging that has taken place in Sumatra, and Kalimantan Provinces is currently been extended to Iriyan Jaya in Papua. Transmigration programme that facilitated human migration from over-populated Java to Kalimantan and Papua also had made an impact on tidal wetland extent (including mangroves) as they have been reclaimed for human settlements and urban expansion to accommodate the migrants.

Thailand

Charuppat & Charuppat (1997) estimated that Thailand’s mangroves have declined 55 per cent of its extent prior to 1961, within 35 yrs. Kongsanchai (1994) also estimates that about 50 per cent of mangrove areas in Thailand have been converted to other land uses before 1991. On contrary, a decrease only of 22 per cent from the mangrove extent in 1973 has been estimated by Wilkies and Fortuna (2003) for the period of 1973-2000 (27 years).

Available information on percentage mangrove loss due to clearing for shrimp pond construction too vary from 33 per cent (Charuppat & Charuppat, 1997) to 65 per cent (Wattayakorn (1998) cited by Giesen et al, 2006). Other causes for mangrove loss include coastal zone development, urban expansion, agriculture, resettlement, construction of harbours and ports, establishment of salt ponds and mining.

Due to re-plantation of mangroves in abandoned shrimp ponds by the Royal Forest Department, the total mangrove extent in Thailand has shown an increase during the past decade (Giesen et al, 2006).

Vietnam

The extensive mangrove areas (400,000 ha) along the sheltered coasts of Vietnam have been destroyed during the war and hence the extent was reduced to 104,123 ha by 1971. Use of the herbicide “agent orange”, artillery and bombardment destroyed 149,850 ha of mangrove forests in the Mekong delta in southern Vietnam (Hong, 2003). In later years mangroves have also been felled for shrimp and fish aquaculture.

Mangrove re-plantation programmes had successfully re-vegetated 96,876 ha of the 155, 290 ha of degraded and destroyed mangrove areas by 1999 (Hong, 2003). Professor Phan Nguyen Hong from the National University of Education in Vietnam who played an active role in the initial phase of the MANGROVE project was awarded the International Cosmos Prize in 2008 for his contribution to rehabilitating mangrove areas of Vietnam.

Unlike other farmed animals, fish don’t have feed available at all times and can’t feed at will. The feeder decides how much feed to offer to the fish. There are no standard feeding practices across the industry, mainly because many factors affect feeding and every pond of fish behave differently. So, feeding catfish is a highly subjective process.

The information in this publication is based on results from feeding studies done over several years at the National Warmwater Aquaculture Center. Consider our recommendations as guidelines, since management practices vary from farm to farm. The guidelines are for feeding healthy fish grown from advanced fingerlings to market size.

Feeding Rate

Several factors dictate how much to feed catfish in a production pond. These include standing crop (number and weight of fish in the pond), fish size, water temperature, water quality, and weather. Generally catfish should be fed daily as much as they will eat without wasting feed and without hurting water quality. Feeding what the fish will eat is especially important when you raise catfish in a multiple-batch cropping system where there are several sizes of fish in the pond, because it is easier for the smaller, less aggressive fish to feed. This type of feeding may be a problem, though, since you might not know when the fish have eaten all they will eat. Thus, it is easy to overfeed, which wastes feed and may hurt water quality.

Feeding rates should not be more than what the fish in the pond need. Long-term average daily feeding rates should not be more than about 120 to 150 pounds per acre. But it is okay sometimes to feed at higher rates. Our data showed that daily feeding the fish as much as they will eat resulted in higher production and weight gain, but feed conversion was increased, compared to feeding a restricted rate of not more than 80 pounds per acre per day. The lower feed conversion in fish fed the restricted rate is mainly because of less wasted feed compared to that of fish fed to their fill. We also found that total feed input, net production, weight gain, and feed conversion were about the same when fish were fed as much as they would eat or fed at a “cut-off” rate of no more than 120 pounds per acre per day under a singlebatch cropping system.

Feeding Frequency

• Once vs. Twice Daily – Generally, feeding once daily is satisfactory for food fish grow out. Research has shown that feeding food fish twice daily is not necessarily beneficial. Although fish fed twice daily were offered more feed than fish fed once daily, the extra feed fed was not completely converted into weight gain. It is likely that feeding twice daily increases feed conversion because, if the feeder is not careful, feed can be easily wasted by overfeeding.
  
  

• Once Daily vs. Once Every Other Day or Third Day – Although we recommend that catfish grown for food be fed once daily, feeding less frequently than daily may be called for under certain circumstances. Our data have shown that fish fed every other day or every third day consume up to 50 percent and 65 percent more feed on days fed, respectively, compared to fish fed once daily all they will eat. The increased feed consumption in fish fed less frequently than daily on days fed is mainly the result of compensatory growth, or at least a partial compensatory growth. Fish can compensate for all or part of the weight loss during a short period of not feeding when you resume full feeding. Although there are some advantages (reduced feed conversion, labor cost, and aeration) to feeding every other day or every third day, we do not recommend this for routine feeding, since fish fed every other day or every third day cannot consume enough feed on days fed to make up for the missed feed on days when you don’t feed them. Also, feeding every other day or every third day appears to reduce fish processing yield, and it extends the production cycle. So, in the long term it may not be economical.
  
  

• Seven Days vs. Five or Six Days per Week – During the growing season, most catfish producers feed their fish seven days a week, but some producers feed six days a week. Our data show that feeding six days a week (not feeding on Sundays) reduced net production by 3.3 percent, and feeding five days a week (not feeding on both Saturdays and Sundays) reduced net production by 6.9 percent, compared to fish fed seven days per week for a growing season. Feed conversion was reduced by 4.8 percent and 7.9 percent, respectively, for fish fed six days and five days a week, compared to fish fed seven days per week. Feeding six days per week may reduce production cost for food-sized channel catfish, but in our study, we used a single-batch cropping system and the fish were fed as much as they would eat. If feed is restricted, you would expect more decrease in net production by feeding six days per week compared to fish fed seven days per week. Also, if you use this strategy in a multi-crop system, skipping feed days may have a more negative impact than in single-crop systems because the smaller fish may lose more weight than was shown in our study.

Maintenance Feeding

Maintenance feeding means that all feed eaten by the fish is used to maintain the animal with no gain or loss of weight. You can get this feeding regimen either by feeding fish a maintenance ration daily or feeding as much as it appears they will eat one or two times per week. Since ponds usually have fish of various sizes, it is better to feed all they will eat on days fed than feeding a little every day. Feeding the fish all they eat on the days fed lets smaller, less aggressive fish feed. Based on our research results, it appears feeding once a week as much as the fish can eat can maintain the body weight of food-sized catfish under a single-batch cropping system. But the condition factor, a nutritional status indicator that measures the relationship between fish body weight and length, is lower for fish fed once a week than fish fed more frequently.

Feeding Time

The best time to feed fish during the day on a large farm is mainly dictated by the logistics required to feed large numbers of ponds in a limited time period. As a result, during warm weather many catfish producers start feeding early in the morning as soon as dissolved oxygen levels begin to increase. This appears to work well. In research we find no advantages to feeding at a certain time of the day. There were no differences in weight gain, feed consumption, and feed conversion among catfish fed to satiation at 8:30 am, 4:00 pm, and 8:00 pm. No differences in emergency aeration time were noted among treatments. But we do not recommend feeding near dark or at night in large commercial catfish ponds unless enough aeration is available, since peak oxygen demand generally occurs about 6 to 12 hours after feeding. This time corresponds to the time when dissolved oxygen levels are low. Generally, it appears most practical to begin feeding in the morning as the dissolved oxygen begins to increase during warm weather. But in cool weather (late fall, winter, and early spring), water temperature is usually higher in the afternoon, and fish will eat better.

Feed Distribution and Duration of Feeding

Since most commercial ponds are relative large (usually 10 acres or larger), it is important to blow the feed over a large area to make the feed accessible to as many fish as possible. It is better to feed on all sides of the pond, but this is usually not possible because of the wind. Feed must be distributed along the upwind side to prevent it from washing ashore.

On a large commercial farm, how long a time to feed the fish in each pond is generally influenced by the number of ponds to feed and the number of feeders. Feeding fish, especially feeding fish to fullness, requires experience and patience. An experienced feeder is invaluable to the farm. The longer the feeder spends feeding each pond, the better chance to optimize feeding. Feeding fish in a hurry often results either in fish being underfed or overfed. As a general rule, in our small research ponds if the fish are actively feeding, they eat all they want in about 30 minutes.

Winter Feeding

Unlike warm-blooded animals, catfish do not feed consistently when water temperature drops below 70 °F. When water temperature drops to 50 °F and below, catfish more or less stop eating. Many catfish producers choose not to feed in winter for a variety of reasons, one of which is that it is difficult to see a positive response from a winter feeding program. But based on research results, winter feeding is beneficial, though how much depends on the severity of the winter.

Fish gain (if fed) or lose (if not fed) more weight during a mild winter than a cold one. Research conducted at Auburn University has shown that food-sized catfish held over winter without feed can lose up to 9 percent of their body weight, while catfish fed 1 percent of their body weight when water temperature exceeds 55 °F gain 18 percent weight over the winter. We, and others, have published charts giving feeding rates and corresponding temperatures for winter feeding, but there is really no precise temperature at which to feed during the winter. As a general rule, if it is warm and fish will eat, it is beneficial to feed.

Since feeding activity of the fish is much lower in the winter than in the summer, it is thought catfish may respond to a sinking feed better than a floating feed during the winter. If you use a sinking feed, make sure it is an extruded feed (slow sink) and not a feed made through a pellet mill. Extruded feeds are more water stable and remain intact longer than a feed prepared in a pellet mill.