Category Archives: Aquaculture

“Production and economic assessment of giant kelp Macrocystis pyrifera cultivation for abalone feed in the south of Chile” (Correa et al 2016)

Citation: Correa, T., Gutierrez, A., Flores, R., Buschmann, A., Cornejo, P., and Bucarey, C. (2016). “Production and economic assessment of giant kelp Macrocystis pyrifera cultivation for abalone feed in the south of Chile“. Aquaculture Research, 47, pp. 698-707. DOI: 10.1111/are.12529

Summary By: Alexandra Pounds

Image Credit: Flickr

  • Big Picture: Farmed kelp for abalone feed in Chile has higher levels of protein. With 30 hectares of production at $78/tonne, the farm would be profitable and return investment within the first year.
  • Abalone farmers in Chile feed kelp to their stock, because other studies have show that it is a better food source for abalone growth. Unfortunately, wild kelp is only available seasonally. Kelp farming is a potential solution to the demand for kelp and prevent overharvesting wild kelp populations. This paper examines whether or not kelp farming in Chile is profitable.
  • Methods:
    • The researchers designed and installed a kelp farm off the coast of southern Chile. They started with 2.4 hectares for 2 years to establish whether the crop would survive the winter season. Afterwards, it was increased to 4 hectares.
    • The researchers used 2 trial units (one in summer, one in winter) to extrapolate annual expenses and yields for a bigger farm.
    • The farm relied on manual labor for picking and planting crop.
  • Results:
    • If the market price for kelp is $78/tonne, a return on investment can be made in the first year by harvesting 30 hectares. The farm would be profitable within one year.
    • Best profitability would be at 50 hectares per year.
    • Protein content of harvested kelp was 9%, which was significantly higher than wild kelp in the area.
    • The summer crop produced significantly greater biomass than the winter crop. Both crops together could produce about 41kg per meter of rope per year.
    • Production costs for 2 harvests (one year), of 10 hectares was $109,396.
      • Fixed costs = 13%
      • Variable costs = 87%
  • Implications
    • Kelp farming in southern Chile could be a profitable way to feed farmed abalone.
    • Placing kelp farms around Chilean salmon farms could increase yield due to higher nitrogen levels in the water. This would have the additional benefit of reducing environmental impacts of the salmon farms.
    • Current kelp prices are not high enough to support farms that produce less than 30 hectares.
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“National Assessment Sheds Light on Educational Needs for Aquaculture in the United States” (Jensen et al 2016)

Citation: Jensen, G., Schwarz, M., Shumway, S., Trushenski, J., Curry Woods, L., Broyles, T., and Mayeaux, M. (2016). “National Assessment Sheds Light on Educational Needs for Aquaculture in the United States”. Fisheries, 41(8), pp. 467-469, DOI: 10.1080/03632415.2016.1199830.

Summary By: Alexandra Pounds

Image Credit: USDA.gov

  • Big Picture: Although demand for highly educated aquaculture workers in the US is increasing and student interest in higher education aquaculture programs is stable, higher education institutions are having trouble recruiting students and are not increasing the number of available programmes.
  • Aquaculture higher education in the US began in the 1970’s in response to the rise in aquaculture. Despite that the industry is growing, high education opportunities are decreasing, with programs shutting down. This study looked at the current aquaculture workforce and examined whether students were interested in pursuing a career in aquaculture to forecast the aquaculture workforce.
  • Methods: conducted a national survey to compile a list of aquaculture high education in the US.
  • Results:
    • 79 respondents,
      • 14 did not offer any courses related to aquaculture (others offered a combination of AA, BSc, MSc, PhD, and/or certificate)
      • 10 of which offered online aquaculture courses
    • Enrolment:
      • Enrolment increased from 2000-2010. Enrolment from 2010 – 2015 was stable.
      • Fewer international students are entering BSc programs. International and national PhD enrolments were equal.
      • Institutions reported challenges with recruiting students for aquaculture.
    • Course offerings:
      • A considerable number of institutions offer programs in aquaculture, many of which are smaller institutions. There have been no new programmes initiated since 2010.
      • Student interest in pursuing a degree in aquaculture seems stable.
      • Online course offerings are growing.
    • Respondents believe that there is a growing demand for employees with advance training in aquaculture.
    • Over the past 10-15 years, job listings in US aquaculture have decreased (especially in academia and government)
  • Implications:
    • The US may not have enough higher education programmes to supply the projected workforce requirements for US aquaculture.
    • The US aquaculture industry growth rate might be held back by the lack of a competent workforce (not enough educated workers).

 

“Strengthening the contribution of aquaculture to food and nutrition security: The potential of a vitamin A-rich, small fish in Bangladesh” (Fiedler et al 2016)

Citation: Fiedler, J., Lividini, K., Drummond, E., and Thilsted, S. (2016). “Strengthening the contribution of aquaculture to food and nutrition security: The potential of a vitamin A-rich, small fish in Bangladesh” Aquaculture, 452, pp. 291-303. DOI: 10.1016/j.aquaculture.2015.11.004

Summary By: Alexandra Pounds

Image Credit: Wikimedia Commons

  • Big Picture: The Mola Production Programme is the most cost-efficient way to address vitamin A deficiencies in Bangladesh.
  • Many small-scale farmers in Bangladesh culture fish, for both commercial and sustenance. Polyculture of rice and fish is an important part of food security in Bangladesh. Many Bangladeshis have small ponds available for aquaculture.
  • It is estimated that 60% of Bangladeshis are vit A deficient, despite the oil and wheat flour fortification programmes.
  • Mola carplet contains more vit A than other commonly eaten fish species in Bangladesh. Producing more mola carplet could help solve the vit a deficiency. The Mola Production Programme is currently behind these efforts. The aim of this paper was to do a cost-benefit analysis of increasing mola carplet production in Bangladesh to help solve the chronic vit A deficiency.
  • Methods:
    • Used national health statistics to establish the usual vit A intake, prevalence of deficiency, and years lost to deficiency-caused disability.
    • They then added how much vit A the Mola Production Programme would provide over the next 11 years to estimate future levels of vit A intake, prevelance of deficiency, and years lost to deficiency-caused disability. They assumed that the Mola Production Programme would have a 30% adoption rate
    • The change in these numbers was compared to the total cost of the Mola Production Programme.
    • They used two different scenarios for comparison.
  • Results:
    • Over 11 years the program would cost $23 million and
      • raise vit A levels by 7 micrograms
      • lower prevelance of deficiency by 1.1%
      • This equates to 3000 lives saved, and prevent 100,000 years lost to deficiency-caused disability.
  • Implications:
    • If continued for 20 years, the Mola Production Programme would have lower costs and greater health benefits than the Vitamin A wheat flour fortification programme.
    • Other nutritional components can be improved through the programme indirectly, via increased income with mola production.

“Increasing fish farm profitability through aquaculture best management practice training in Egypt” (Dickson et al 2016)

Citation: Dickson, M., Nasr-Allah, A., Kenawy, D., and Kruijssen, F. “Increasing fish farm profitability through aquaculture best management practice training in Egypt”. Aquaculture, 465, pp. 172-178. DOI: 10.1016/j.aquaculture.2016.09.015

Summary by: Alexandra Pounds

Image Credit: Wikimedia Commons

  • Big Picture: Fish farms in Egypt that adopt BMP are more profitable than those that don’t. Having BMP can increase the farm’s profitability, mostly due to better feed management practices.
  • Egyptian aquaculture is growing, but farmers had little training or education resources. Best Management Practices (BMP) training programmes were introduced to help. This survey examined whether or not implementing the BMP had resulted in greater profits and productivity.
  • While BMP are usually precursors to many certifications, farmers may see them as a burden rather than a help.
  • Aquaculture represents 77% of Egyptian fish production (mostly tilapia and mullet)
    • 85% = pond-based
    • 15% = cages, rice fields, and intensive farms
  • Key messages from BMP training:
    • reduce overall stocking rates to harvest more fish at larger sizes
    • fertilize the pond to stimulate plankton growth (an additional food source for fish)
    • reduce feed waste and use high-quality feed
  • Methods:
    • Farms that had implemented BMP were compared with farms that had not implemented BMP.
    • Data from 3715 farms were used, 70% of which were considered “high adopters” of BMP
    • An online questionnaire was distributed, and some farmers were interviewed.
  • Results:
    • BMP farms were more likely to practice mullet & tilapia polyculture rather than tilapia monoculture.
    • BMP training resulted in increased profitability, but had no effect on productivity. Average annual net profits were $15,000 greater in BMP farms than non-BMP farms.
    • BMP mostly improved feed and fertilizer management, which improved FCRs. BMP farms used less feed.
    • Operating costs were lower in BMP Farms.
    • There was no difference in total sales between BMP and non-BMP farms
    • BMP did not make a difference to total yield; however, farms with BMPs had larger average fish sizes.
    • BMP farmers were younger and had smaller families than non-BMP farmers (although this was not statistically significant). Statistically, the BMP farmer and non-BMP farmer demographics had no differences.
  • Limitations
    • There may have been some selection bias, as farmer interviews were selected based on connection with certain BMP trainers.

“Temperature effects on growth, feeding rate and feed conversion of the Pacific white shrimp (Penaeus vannamei)” (Wyban et al 1995)

Citation: Wyban, J., Walsh, W., and Godin, D. (1995). “Temperature effects on growth, feeding rate and feed conversion of the Pacific white shrimp (Penaeus vannamei).” Aquaculture, 138(1-4), pp. 267-297. DOI: 10.1016/0044-8486(95)00032-1

Summary By: Alexandra Pounds

Image Credit: Flickr

  • Big Picture: As shrimp grow, the optimum temperature for growth decreases. Different sized shrimp require different temperatures for optimum growth. FCR was more related to shrimp size than to temperature, where smaller shrimp had better FCRs.
  • This experiment tests the effects of temperature on juvenile growth rate, feeding rate, and feed conversion.
  • Methods:
    • 4 experiments: 4 different temperatures, 3 different stocking sizes
    • Indoor laboratory setting (recirculating system), big enough to allow room for normal swimming behaviour
    • System, water quality, flow rates, photoperiod, and feed were standardized across all tanks
    • Shrimp were stocked at 50 shrimp / m3
    • Feed consumption was calculated by feed supplied minus residual feed (visually estimated feed at bottom of tank)
    • Used pond water (and sea water at the end to test if there was a difference)
    • Temperature was measured twice daily
    • Statistics used: one-way ANOVA, orthogonal contrast, and multivariate F-tests
  • Results:
    • Shrimp grew bigger and ate more with warmer temperatures.
    • FCR depended on stocking size, but not temperature. FCR was inversely related to size: Larger shrimp had less efficient FCRs.
    • Smaller shrimp ate more food at all temperatures.
    • Optimum temperature was size-specific. Large shrimp had optimum temperature of 27 deg C, while small shrimp (<5g) had an optimum temperature of over 30 deg C.
      • Reduced feeding & growth below 23 deg C for all sizes
      • Reduced feeding & growth above 30 deg C for large shrimp
      • Optimum temperatures for growth:
        • Small shrimp: >30 deg C
        • Medium shrimp: 30 deg C
        • Large shrimp: 27 deg C
      • Optimum temperatures for lowest FCR:
        • Small shrimp: FCR unaffected by temperature
        • Medium shrimp: 27-30 deg C
        • Large shrimp: 27 deg C
      • As shrimps get bigger, they become less efficient at growth and more sensitive to temperature
  • Limitations
    • Dissolved oxygen (DO) was not constant across tanks, as dissolved oxygen is lower when temperatures are higher. However, DO was always above 90% saturation.

“Commercial aquaponics production and profitability: Findings from an international survey” (Love et al 2015)

Citation: Love, D., Fry, J, Li, X., Hill, E., Genello, L., Semmens, K., Thompson, R. (2015). “Commercial aquaponics productio and profitability: Findings from an international survey.” Aquaculture, 435, pp. 67-74. DOI: 10.1016/j.aquaculture.2014.09.023

Summary By: Alexandra Pounds

Image Credit: Wikimedia Commons

  • Big Picture: Commercial-scale aquaponics is a relatively young industry, and this study was unable to determine if it will be profitable. The study did examine what most common practices were for aquaponics production in the USA. 
  • While many studies have focused on lab-scale or small-scale aquaponic production, his study aimed to examine commercial-scale aquaponics production. It looked at methods, yields, and profitability.
  • Methods:
    • Online international survey, responses were collected over 3 months
    • They used several statistic and data software to help with analysis.
  • Results:
    • Responses:
      • 257 responses. Only 188 were considered “commercial” producers.
      • 81% of responses were from the USA.
      • 77% of responses were male.
      • 93% had more than high school degrees, 27% had a graduate degree.
      • As less than 10% had been farmed for more than 10 years, it indicates that the industry is growing and experience levels are low.
    • FACILITY: 41% used greenhouses & a second facility. 31% used only a greenhouse, and 4% used rooftop farming. 74% owned the property.
    • SYSTEM: 71% designed the system themselves. 29% purchased a kit or hiring a consultant.
      • 43% used supplemental lighting
      • 43% raised or bred their own fish using a nursery or hatchery.
      • Media:
        • 77% used floating rafts
        • 76% used media beds
        • 29% used nutrient film technique
        • 29% used vertical towers
        • 6% used wicking beds
        • 5% used Dutch buckets
      • Production & Food Safety:
        • Over 50% did not have on-site cooling facilities
        • 33% did not have on-site bathrooms or adequate hand-washing facilities
        • 38% lacked a food safety plan (indicating educational needs)
    • PRODUCTION:
      • Median quantity animals: 23 to 45 kg/yr
      • 24% did not harvest any fish in the past year, probably because they were new operations
      • Median quantity of plants: 45 to 226 kg/yr
      • Production is skewed towards plants (ie, on average, aquaponics farmers produce more plants than animals). This is probably because:
        • particular species of plants were more valuable than the fish (herbs versus tilapia)
        • plants grow faster than animals, and can be harvested sooner
        • biomass conversion ratio for plants is better than fish – for example, 9kg of lettuce can result from fish manure from 1kg of fish feed, whereas feed conversion ratios of fish are around 1:1
    • SPECIES:
      • Aquatic animals: tilapia (69%), ornamental fish (43%), catfish (25%), “other” (18%), perch (16%), bluegill (15%), trout (10%), and bass (7%).
      • Most farmers raised 2-3 species of animal.
      • Plants: basil (81%), salad greens (76%), non-basil herbs (73%), tomatoes (68%), head lettuce (68%, kale (56%, chard (55%, bok choi (51%) peppers (48%), and cucumbers (45%)
    • MARKET: sold to a variety of market types, including grocery stores, farmer’s markets, etc. Many sold at their own farm.
    • PROFITABILITY:
      • 30% of respondents used the aquaponics as their main source of income
      • 31% of respondents reported that their business was profitable over the last 12 months.
      • Median gross sales revenue: $1000-$5000 over 12 months
      • 10% of respondents received over $50,000 over 12 months
      • those that sold other products (other than fish & plants) were more profitable
      • those who were more knowledgeable were over 2x as likely to be profitable.
      • those who used aquaponics as their primary source of income were over 5x as likely to be profitable.
      • Those who had >$5000 in revenue were more likely to be profitable
    • SUMMARY: The following characteristics were statistically associated with profitable businesses:
      • aquaponics was the primary source of income
      • located with the USDA’s “plant hardiness zones” (zones with annual extreme temperatures above 0 deg F)
      • gross sales revenue >$5000
      • greater aquaponics knowledge
      • sales of non-food products (ie, agrotourism, consulting, supplies)
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“Effect of probiotics on growth performance and digestive enzyme activity of the shrimp Penaeus vannamei” (Wang 2007)

Citation: Wang, Y. (2007). “Effect of probiotics on growth performance and digestive enzyme activity of the shrimp Penaeus vannamei.” Aquaculture, 269(1-4), pp. 259-264. DOI: 10.1016/j.aquaculture.2007.05.035

Summary By: Alexandra Pounds

Image Credit: Flickr

  • Big Picture: Shrimp receiving probiotics grew bigger and had better digestion than those without probiotics; however, higher concentrations of probiotics did not result in bigger shrimp.
  • This study investigated whether adding probiotics to shrimp’s diet would affect their growth and ability to digest food.
  • Other studies have found that β-glucans, lipopolysaccharides, peptidoglycans and probiotic bacteria can help boost the immunity of shrimp, but did not look at growth.
  • Probiotics were added to the food at different concentrations.
    • Probiotics used: Photosynthetic bacteria and Bacillus sp. (grown in the lab)
    • Concentrations used: T-1, 2 g kg 1 (1 g kg 1 lyophilized photosynthetic bacteria cells (PSB) and 1 g kg 1 lyophilized Bacillus sp. (BS)); T-2, 10 g kg 1 (5 g kg 1 PSB and 5 g kg 1 BS); and T-3, 20 g kg 1 (10 g kg 1 PSB and 10 g kg 1 BS).
  • Methods:
    • 28 days
    • 3 replicate groups for a total of 12 tanks were used.
    • Shrimp were fed 3 times per day with the same pellets, with different additions of probiotics.
    • water quality was kept the same for all the tanks.
    • Shrimp started out at the same size.
  • Results:
    • Shrimp receiving probiotics grew better than the control (no probiotics).
    • Shrimp receiving different concentrations of probiotics did not show any differences in growth.
    • T-2 and T3 had the best digestion (based on enzyme activity levels)
    • Probiotics did not seem to affect water quality.