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