Neco 2017 Fishery answers – may/june exams

FISHERIES OBJ:
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21ADABEBBEEC
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41DADDDACDEC
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3ai)
Fish Breeding is a complex issue when examining and comparing commercially important fish species, be that mollusc, crustacean or teleosts.



1ai)
i)Low technology
ii)Seeds scarcity and inadequacy
iii)Land restriction
iv)Technical problem associated with production and management
v)Water pollution
1aii)
i)THE LAND
ii)THE SOURCE OF WATER
iii)ACCESSIBILITY
iv)SECURITY
v)FAR AWAY FROM POLLUTION

1bi)
i)Low Capital Investment:In addition to the on-farm production possibilities of organic fertilizers, organic fertilizers help in maintaining the soil structure and increasing its nutrient-holding capacity
ii)Fertility of Soil:Organic fertilizers ensure that the farms remain fertile for hundreds of years.
iii)Safe Environment:Organic fertilizers are easily bio-degradable and do not cause environmental pollution.
iv)Employment:We all know that chemical fertilizers are made in large plants that are automated and have an annual capacity of millions of tons.
v)On-Farm Production:The majority of organic fertilizers can be prepared locally or on the farm itself.
1bii)
i)Dissolved Oxygen It is the amount of oxygen dissolved in water. Most aquatic organisms need oxygen to survive and grow.
ii)Temperature is a measure of the average energy (kinetic) of water molecules. It is measured on a linear scale of degrees Celsius or degrees Fahrenheit.
iii)Electrical Conductivity/Salinity Solids can be found in nature in a dissolved form. Salts that dissolve in water break into positively and negatively charged ions. Conductivity is the ability of water to conduct an electrical current, and the dissolved ions are the conductors.
iv)pH is a measure of how acidic or basic (alkaline) the water is (the term pH comes from the French: “puissance d’Hydrogène” which means strength of the hydrogen). It is defined as the negative log of the hydrogen ion concentration.
v)Turbidity is a measure of the amount of suspended particles in the water. Algae, suspended sediment, and organic matter particles can cloud the water making it more turbid.
Suspended particles diffuse sunlight and absorb heat.

 

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