2023 NECO Fisheries Objective & Essays Answers

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Fishery OBJ

1. pH regulation: Lime helps to stabilize and maintain the pH level of the pond water, creating a suitable environment for aquatic life.
2. Alkalinity enhancement: Lime increases the alkalinity of the water, which is beneficial for the growth and survival of many aquatic organisms.
3. Pond bottom conditioning: Lime can be applied to the pond bottom to improve its condition and reduce harmful substances like hydrogen sulfide.
4. Nutrient precipitation: Lime can aid in the precipitation of excess nutrients, helping to control algae blooms and maintain water quality.

– Aquaculture: Aquaculture refers to the farming or cultivation of aquatic organisms, such as fish, crustaceans, mollusks, and aquatic plants, under controlled conditions for commercial, recreational, or conservation purposes.
– Aquariculture: Aquariculture is a specific subset of aquaculture that focuses on the cultivation and management of aquatic plants and animals in aquariums for ornamental purposes.

(i) Difference between salting and brining in fish processing:
Salting involves the application of dry salt directly to the fish, while brining is a process where the fish is soaked in a saltwater solution (brine) to preserve and flavor it.

(ii) Similarities between salting and brining in fish processing:
Both salting and brining are preservation methods used in fish processing to extend the shelf life of the fish by inhibiting bacterial growth and enzyme activity. Additionally, both methods enhance the flavor of the fish by adding salt.


1. Water Filtration: The recirculatory system includes advanced water filtration mechanisms to remove waste and maintain water quality for the fish.
2. Oxygenation: The system incorporates equipment to ensure adequate dissolved oxygen levels, critical for the health and growth of the fish.
3. Biosecurity Measures: Recirculatory systems often have measures in place to prevent the introduction of pathogens and diseases into the fish population.

1. Lower Cost: Building and maintaining earthen ponds is generally less expensive than concrete ponds, making them more accessible to fish farmers with limited budgets.
2. Natural Environment: Earthen ponds provide a more natural environment for the fish, which can promote better growth and overall health.
3. Environmental Adaptability: Earthen ponds can be designed to match the local environment, taking advantage of existing landscape and water resources, which may result in better sustainability and reduced ecological impact.

2. lakes

(2aiii) A barrage pond is a type of pond created by constructing a barrage or dam across a river or stream to impound water for fish farming.

(2aiv) Two similarities between Oreochromis niloticus (Nile tilapia) and Heterobranchus bidorsalis (African catfish) are that they are both commonly used in aquaculture and are known for their tolerance to a wide range of environmental conditions.

(i) Water quality parameter refers to specific characteristics or measurements used to assess the suitability of water for fish farming, such as temperature, dissolved oxygen, pH, ammonia levels, etc.

(2bii) Four ways of improving dissolved oxygen in an earthen pond are through aeration systems, increasing water exchange, managing organic matter, and using aquatic plants to oxygenate the water.

(2biii) Two differences between polyculture and integrated fish farming are that polyculture involves farming multiple species of fish together in the same pond to utilize different niches, while integrated fish farming combines fish farming with other agricultural practices like poultry or vegetable cultivation for mutual benefits.

Fishing is the activity of catching, harvesting, or capturing fish and other aquatic organisms from their natural habitats, usually for commercial, recreational, or subsistence purposes.

(i)Fishing Nets
(ii)Fishing Hooks and Lines
(iii)Fishing Traps

To calculate the area of the pond in square meters (m^2), We use the formula: Area = Length × Breadth

Length = 50,000 cm
Breadth = 25,000 cm

First, convert the measurements to meters:
Length = 50,000 cm ÷ 100 cm/m = 500 meters
Breadth = 25,000 cm ÷ 100 cm/m = 250 meters

Now, calculate the area:
Area = 500 meters × 250 meters = 125,000 square meters (m^2)

– Endo-parasite: An endo-parasite is a parasite that lives inside the host’s body, such as in organs, tissues, or blood vessels.
– Ecto-parasite: An ecto-parasite is a parasite that lives on the host’s body surface, such as the skin, fins, or gills.

(i)Weight loss and reduced growth rate.
(ii)Increased mucus production and skin irritation.
(iii)Abnormal swimming behavior, such as flashing or rubbing against objects.
(iv)Fins clamping or fin erosion.
(v)Presence of visible parasites on the fish’s body or gills.

(i)Install a strong and secure fence around the pond to prevent alligator access.
(ii)Implement regular monitoring and surveillance to detect any alligator presence early and take appropriate action.
(iii)Educate and inform people in the area about alligator behavior and safety measures to prevent future incidents.

(i)Both are passive fishing gears that rely on fish swimming into them to be captured.
(ii)They are widely used in commercial fishing to catch a variety of fish species and are designed to be efficient in their respective fishing environments.

Fish preservation involves methods of preventing or slowing down the spoilage of fish after harvest. This can be done through methods like chilling, freezing, salting, smoking, drying, and canning.

Fish processing, on the other hand, involves the transformation of fish into forms that are ready for consumption or further processing. This includes methods like filleting, skinning, deboning, mincing, and grinding.

– Refrigerators or freezers
– Coolers or ice boxes
– Salt
– Smokehouses
– Drying racks

– Refrigerators or freezers operate by using a circulating refrigerant gas that absorbs heat from the fish and expels it outside. This leads to a reduction in temperature, which helps to slow down bacterial growth and preserve the fish.
– Salt is used as a preservation method primarily for fish that are to be cured or dried. The fish is coated with salt, which draws out moisture and creates an environment that is not conducive for microbial growth.
– Smokehouses are used for smoking fish, which involves exposing it to smoke from burning wood chips. This imparts a distinctive flavor and color to the fish, and also helps to preserve it by slowing down the growth of bacteria and parasites.

– Moringa: This is a plant that is commonly used in traditional medicine and as a food source in many parts of the world. The leaves of the moringa tree can be dried and ground into a powder, which can be added to fish feed to boost its nutrient content. Moringa is rich in vitamins, minerals, and protein, and has antioxidant properties that help to improve fish health and growth.
– Soybean: Soybean meal is a popular ingredient in fish feed due to its high protein content and amino acid composition. Soybean is a plant-based protein source that is easily digestible by fish, and can be used as a substitute for fishmeal, which is a finite resource.

– Manual method of fish feeding involves hand-feeding fish at regular intervals. This is usually done in small-scale fish farms or recreational ponds, where the number of fish is manageable. The feed can be delivered directly to the water surface, or scattered over the pond.
– Feeding frequency refers to the number of times per day that fish are fed. This can vary depending on the species of fish, their age and size, and the conditions of the pond. Generally, fingerlings and juveniles require more frequent feeding than adult fish. Overfeeding can lead to water pollution and disease outbreaks, while underfeeding can result in stunted growth and poor health.

– Both plastic ponds and tarpaulin ponds are types of portable or temporary fish ponds that can be easily set up and dismantled.
– They are both made from lightweight and durable materials that are resistant to punctures, tears, and UV damage. This makes them ideal for outdoor use, especially in areas where land is scarce or expensive.

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