Aquaculture of Fishes Biology of Fishes 11.6.12
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Transcript of Aquaculture of Fishes Biology of Fishes 11.6.12
Aquaculture of FishesBiology of Fishes
11.6.12
Presentation Guidelines Syllabus Revisions Guest Lecture 2 – Dr. Charles Madenjian – USGS Great Lakes
Science Center Aquaculture – related to fish ecology & diversity
Overview
Guidelines online All groups submit written reports 11.27.2012 Attendance required at all student presentations Student Presentations material will be on Final Exam
Presentation Guidelines
November 13 – Biogeography, conservation, genetics
November 15 – Conservation ecology case study synthesis
November 20 – Exam 2 November 22 – Thanksgiving Break November 27 – Student Presentations
November 29 – Guest Lecture 3
December 4, 6, 11 – Student Presentations
Syllabus Revisions
Dr. Charles Madenjian – USGS Great Lakes Science Center Dynamics of the Lake Michigan Food Web 1979-2000 Assignment Part 1 hard copy due at start of class
Guest Lecture 2
Aquaculture – the farming of aquatic organisms under controlled conditions (fishes, crustaceans, mollusks, aquatics plants, etc).
Farming of fishes is the most common form (what we will focus on).
2 Primary categories we will focus on (often overlap) Grow-out aquaculture for direct human consumption Hatchery and stocking operations – release fishes into wild
to supplement exploited or declining stocks
Aquaculture
Aquaculture – example types Mariculture – cultivation of marine organisms in seawater Polyculture – cultivation of multiple species Integrated Multi-Trophic Aquaculture – by-products of one
species are recycled as inputs for another species
Aquaculture
Aquaculture – example types Extensive – utilizes cages/pens, but relies on natural food
supply Semi-intensive – feeding supplements or fertilizer to
encourage feed production Intensive – highly subsidized, large inputs of feed; highest
yields, but highest ecological impacts
Aquaculture
Aquaculture – the farming of aquatic organisms under controlled conditions
Practiced by humans for thousands of years 6000 BC Australia – eel culture via landlocked ponds 2500 BC China – carp aquaculture 1000 years ago in Hawaii – oceanic ponds
Aquaculture
Aquaculture
Global harvest of aquatic organisms in million tons, 1950–2010, (Food & Agriculture Organization of UN)
Fisheries provide 16-19% of human animal protein consumption
~1 billion people rely on fish for most of their protein (especially in developing nations)
Increased pressure on fisheries with increasing population Wild supply/CPUE leveled off at 90 MMT in late 1980s Yields increased in recent years to 120 MMT largely due to
aquaculture Aquaculture expanded from 5 MMT (1950) to 30 MMT (1990s)
Aquaculture will be needed, but can it be done sustainably?
Aquaculture
Pros Economically important Access to animal protein Relieve pressure of overfishing Restocking wild populations, conservation (captive
propagation) Cons
Ecological efficiency (lack thereof) Pollution (disease, parasites, nutrient loading) Escapes
Aquaculture
Usually done to enhance growth rate Highly debated, lack of solid research Growth hormones Antifreeze genes
Genetically Modified Organisms (GMOs)
Pros Increased growth & feeding efficiency (market size faster)
tilapia +60-80% faster growth, 2.9x feed conversion, 3.6x less food Chinook salmon – 10-30x growth rate w/ hormone & antifreeze
genes
Increased disease resistance Potential health benefits (lower cholesterol)
Genetically Modified Organisms (GMOs)
Cons Deformities Non-adaptive characteristics (feeding behavior, swimming
ability) Perceived potential health hazards (not well-supported*)
Genetically Modified Organisms (GMOs)
Example species/systems Atlantic salmon – sea ranching Bluefin tuna – sea ranching Tilapia – intensive aquaculture Carps – polyculture Air-breathing fishes – sustainable aquaculture
Aquaculture
“Sea Ranching” - process of growing out salmon in net pens until market size.
Atlantic salmon (Salmo salar) most common species International scale practice (Norway, Chile, Canada = ~85%
production in 2005) 1.3 million metric tons (2005), 90% S. salar; $4-5 billion USD Pros: increased economic activity; healthy animal protein at
reasonable price; pressure off wild stocks Cons: low ecological efficiency, 2.5 kg fishmeal: 1 kg salmon
Aquaculture
Cons Low ecological efficiency Socioeconomic hardships (compare to wild-stock fisheries) Pollution (high density – high waste, nutrient pollution,
organic sewage of 40 salmon ~ 1 person) Parasites, disease, antibiotics, pesticides (although
debatable in some comparisons to wild fish) Escapes (disease, hybridization, competition)
Sea Ranching
Cons
Sea Ranching
Bluefin tuna (Thunnus thynnus) Very early stages, minimal success Large species, special requirements May contribute to current overfishing Valuable species ($396,000 for one fish)
Aquaculture
Bluefin tuna (Thunnus thynnus)
Aquaculture
Tilapia (Oreochromis spp.)
Aquaculture
Carps (various cyprinid species), commonly polycultured Grass, silver, bighead, common carps Cultured primarily in Asia Introduced in US and elsewhere
Aquaculture
Air-breathing fishes – several species (Channa, Clarias, Osphronemus, Arapaima, Protopterus, Atractosteus)
Numerous advantages over other fishes
Aquaculture
Air-breathing fishes – several species (Channa, Clarias, Osphronemus, Arapaima, Protopterus, Atractosteus)
Numerous advantages over other fishes Tolerant of lower water quality (conducive to high-density culture) Lower technology required for culture Most species exhibit rapid growth and readily accept artificial feed May be more adaptive options for culture in the face of climate
change
Aquaculture
Air-breathing Fishes
Air-breathing Fishes
Will likely be a necessity to meet future fish & seafood supply and demand
Sustainable practices necessary to reduce negative impacts
High economic potential Much further research is necessary
Aquaculture