WAEC FISHERY ANSWERS
specimen A is greenish in colour due to the presence of algae while specimen is colourless
the green colour observed is specimen A is due to presence of planktonic algae which is absent in specimen B
specimen B is more suitable for table fish
thepresence of planktonic algae will deplete valuable from getting to the water
specimen B contains harmful algae blooms,bacterial, and virus which can kill the fishes.
i)by attacking the food source of the algae to reduce its breading
ii)by treating the water to be used for the table fish before using it
iii)by filtering the water before use.
iv)by sterilizing the water
v)by the use of herbicides to kill the algae
i)Rinse your cast nets with fresh water and hang until your entire net is completely dry, do not use any soap, detergents or chemicals to clean your cast nets.
ii)For your drying period, drape your net over something or hang it up slightly but “do not” hang the net up completely so that the weights leave the ground.
iii)Never store your net wet, when moisture and fish slime mix together for any length of time, ammonia settles in and you’ll be amazed at how quickly your cast net will disintegrate if you store your bucket unrinsed and wet.
Uses of mattock
i)a mattock is a versatile hand tool, used for digging and chopping grounds for pond construction.
Uses of shovel
i)a shovel is a tool for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore for d construction of fishponds
1a list ten examples of ornamental fishes
1b what are the marketing channels for fish
1c differentiate between extensive and intensive fish culture
5a list and explains the following
5b draw the side view of an concrete pond
Fish product flow can follow various channels from the fish producer including fisherfolk and aquaculturalist to the final consumer and can involve varying number of stages. Therefore, the fish market was divided into four main stages: the producer stage, the wholesaler stage including processing, the retailer stage, and the consumer stage including the export and institutional consumer markets.
The above sections examined the product channels from fish producers to fish consumers in terms of sales. The following paragraphs discuses the method of payment to the fish producfers.
In this section, examines how fish was traded in the market and how market operators could come together for fish trading.
Phosphorous is an essential mineral for fish, as well as usually being the limiting nutrient in aquatic ecosystems.
Fish obtain P almost exclusively from their diet. Most diets used in intensive culture have P in excess to the needs of the fish, or in a form which partially unavailable to the animal.
Surplus P is excreted either by the kidneys or in the feaces.
In intensive pen or cage farming, for every kg of fish harvested, the environment can be enriched by as much as 0.75 kg of Carbon, 0.023 kg of Phosphorus, and 0.1kg of Nitrogen. This can be calculated in a variety of ways, using measurements on the water body, or by using the published data on P content of feeds, the FCR (Food Conversion Ratio), and the P content of fish carcasses.
The concentration of total P in a water body is determined by the P loading, the size of the water body (surface area, mean depth), the flushing rate (what perdentage of the total volume is lost anually through over flow) and the part of P permanently lost in the sediments.
In temperate climates, it is best to determine the total P concentrations during the spring overturn, as during most of the year stratification of the water column might result in faulty measurements. In tropical climates, total P should be determined as the mean measured surface P over one year.
Predicting the effects of extensive farming on an aquatic ecosystem is very imprecise. It is based on the relation between the primary productivity of the water body and the production of fish. Theoretically, 10–15% of the primary production could be converted into fish (tilapia) tissue.
This theoretical assimilation value is 20 time better than what happens in well managed fish ponds, which in itself is much more efficient than in nature. In highly productive ponds, the figure is about 1.4%, and about 1.3% in less productive systems. Estimates of extensive sage farming, where the fish are more concentrated and than in enclosures and depend largely on plankton, very 1.0% to 3.5% of the primary productivity.
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