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- Fish refers to the vertibrate and invertibrate animals that inhabit the aquatic habitat
- a distinct feature is that they respire via gils
- term also used to refer to the parts of these animals that we use as food
what is a distinct feature of fish?
they respire via gils
Fish are an excellent source of which nutrients?
- fat (essential FAs)
- vitamins (B2, B6, B12, C, A, D)
- minerals (Ca, P, Mg, Fe, Zn, Se, I)
What is the world fish catch in millions of tons?
>90 million tons
What are the leading fish producing and exporting countries?
China's fish produciton bas been increasing. From1990- 2000 production has tripled, why?
sophisticated harvesting methods
What precent of fish captured will be used for food?
Why will fish production increase?
- growing populations, fish is a major source of animal protein especially in developing countries
- health benefits of fish vs. red meat
About how many fish species are known? What precent of the species are consumed as food?
- ~35,000 species known
- 75-80% are consumed as food
What are the different types of shell fish?
What are some examples of crustacia (shell fish)
what are the different types of molluscs (shell fish)
what are some examples of echinoderms (shell fish)
What are some examples of gastropods (moluscs, shell fish)
What are some examples of cephalopods (moluscs, shell fish)
What are some examples of bivalves(moluscs, shell fish)
What are true fish?
- tend to have a torpido/elliptical shape
- boney: cod, talipia, salmon
- cartilaginous: sharks, rays, skates
Give examples of the different ranges of flavor of fish.
- mild flavor: sole, flounder, hoki, hake, halibut
- moderate: cod, lobster, scallops, oyster
- intense flavor: salmon, tuna, mackerel
Give some examples of the different ranges of texture between fish species.
- soft or delicate: anchovies, bass, porgy, herring, hake, sea urchins
- medium: cod, salmon, tilopia, snapper, shrimp
- firmer: catfish, dogfish, strugeon, tuna, scallops, lobster
What are Piokilotherms?
- cold blooded
- tend to maintain body temperature within 1°C of the ambient water temperature
- shell fish and true fish
what are endotherms?
- have a body temperature much higher then ambient temperature ~20°C
- white shark, sturgeon, tuna
What % of fish are eaten fresh?
What % of fish are frozen?
What % of fish are canned?
What % of fish are smoked/salted and dried marinated?
What are non-food uses of fish?
- fish meal
- fish oil
What are some trash fish and why?
- Herring (bones)
- Mackerel (color and fat content)
- Tuna (bones)
- still have good nutritional value though
What are health benefits of fish?
- nutritive quality
- DHA (doccohexonic acid) brain lipid useful for brain development and CV system function- good for lowering blood CH
What are some hazards of fish?
- heavy metals (Pb, Hg, Cd, As)
- Fish allergens
- Biogenic amines
What are some of the effects of heavy metals?
- metallic taste in your mouth
- renal degeneration
- a variety of cancers
What is the major allergic protein in fish?
What are examples of biological amines? What fish are they found in high levels in?
- His (Histidine --HO--> Histamine)
- Tyr (Tyrosine --TO--> Tyramine)
Tuna, mackerel, herring
What are the negative health effects of microalgea on shell fish?
- microalgea release various metabolites such as domic acids that are abs. by the shellfish
- when the shellfish are consumed may cause health hazards
What fish is particularly prone to parasites?
What do these parasites do?
- Alaskan Pollock
- parasites release proteases that make the structure soft
T or F
proximate composition is similar for true fish and shell fish
Why is there greater variation in fish composition then beef?
variation is due to species difference, season of harvest, diet, nutritional status, sex, age, etc.
What is high protein fish?
- protein content ~28%
What are low protein fish?
What is gout?
gout - protein --> uric acid --> crystallizes in joints must avoid high protein food
What are the seasonal variation in Herring?
- protein content tends to be uniform throughout the year
- in the summer months when fish is actively feeding fat content is much higher
What are the seasonal variation in Mackeral?
- protein content stays uniform throughout the different seasons
- in the spawning season fat content declines b/c the reserves are used up for energy
What are some high fat fish?
Where do high fat fish tend to swim?
- swim closer to the surface
Where is the fat in high fat fish stored?
fat tends to be deposited in the muscle and around the belly cavity
What is the fat content in low fat fish?
Where is the fat stored in low fat fish?
in the liver
what are some low fat fish?
Where do low fat fish swim?
- swim closer to the bottom of the ocean
- demersal fish
What is the chemical composition of fish closely related to?
- migratory behavior
What are the two layers of fish skin?
- outter epidermis
- inner epidermis
What are the characteristics of the outer epidermis?
- higher moisture content
- PL and mucosal cells
- numerous gland cells that produce the Mucopolysaccharides
- rich mucous responsible for the slimy surface
What are characteristics of the slime produced by the outer epidermis.
- mainly micropolysaccharides
- makes them difficult to catch- defense
- makes hard for microorganisms to attack