Fundamentals of Fisheries & Aquaculture PDF

**[FUNDAMENTALS OF FISHERIES]** **Fisheries** -- refers to all activities relating to the act or business of fishing, culturing, preserving, processing, marketing, developing, conserving and managing aquatic resources and fisher areas, including the privilege to fish or take aquatic resource thereo...

**[FUNDAMENTALS OF FISHERIES]** **Fisheries** -- refers to all activities relating to the act or business of fishing, culturing, preserving, processing, marketing, developing, conserving and managing aquatic resources and fisher areas, including the privilege to fish or take aquatic resource thereof (RA 10654). **Aquaculture** - The farming of aquatic organisms in inland and coastal areas, involving intervention in the rearing process to enhance production and the individual or corporate ownership of the stock being cultivated ( FAO). -Fishery operations involving all **forms of raising and culturing fish** and other fishery species in fresh, brackish, and marine water areas (RA 8550; RA 10654) **[AQUACULTURE: WORLD SCENARIO]** - In **2018**, the **Philippines ranked 8th among the top fish producing countries in the world** with its total production of 4.35 million metric tons (MT) of fish, crustaceans, mollusks, and aquatic plants (including seaweed). - In terms of aquaculture production, the country ranked 11th in the world with 826.01 thousand MT or 1.01% share of the total global aquaculture production of 82.10 million MT. - The **total value of the country's aquaculture production** including fish, crustaceans, and mollusks is **USD 1.89 billion** (FAO, 2020). - The **Philippines is also the world's 4th largest producer of aquatic plants** (including seaweed) having a total of 1.48 million MT or 4.56% of the total world production of 32.39 million MT (FAO, 2020). **[CLASSIFICATIONS OF AQUACULTURE]** **Aquatic Environment** **Freshwater Aquaculture** - This involves the culture of organisms that live mainly in inland waters with 0.1 parts per thousand (ppt) or less salt content. **Brackishwater Aquaculture** - This involves the culture of organisms that live in water with a salt content between 0.1ppt and full strength seawater. **Mariculture** - This involves the culture of organisms that live in coastal lagoons or in the open sea. **End-product** **Seed Production** - The main objective of this type of culture is to produce small fishes or other organisms, usually called "seed," which are stocked into ponds or other culture devices to be grown into adult organisms for market. **Grow-out Production** - The main objective of this type of culture is to grow seed stock until the commercial size or weight is achieved. **Broodstock Production** - The main objective of this type of culture is to grow, breed and improve cultured species genetically, so as to improve aquaculture productivity. **Level of Intensity** - Extensive Aquaculture - Semi-Intensive Aquaculture - Intensive Aquaculture depending on the following: - Stocking and fertilization rates - Supplementary feed quality and rates - Level of technology employed - Level of investment and resultant yields - **Stocking rate** is defined as the **number of fish seed stocked per unit water surface**, with due consideration to the size and/or age group of the stocking material (**e.g. 10 pcs per m^2^**). - **Stocking density** is **the total number of animals (or liveweight) on a part of the area** for a certain portion of time (**100,000 pcs** in a particular area). - **Fish seed** refers to the **fry**, **post-larvae** and **fingerlings** of the species to be cultured, and they are usually obtained from natural waters and hatcheries. **Extensive Culture** - This is the **simplest method of culture**, and is characterized by a low stocking rate, use of fertilizer, little or no use of supplementary feed and consequently, a relatively low level of technology. - As a result, the **level of investment is low**, and consequently, **yields are low**. - Stocking rate is **1 to 4 fish per square meter**. - Availability of food is enhanced by the **application of fertilizer**. **Semi-intensive Culture** - This method of culture is **more complicated than the extensive method of culture**. - The stocking rate used is higher, both feed and fertilizer may be used, and consequently, the level of technology is higher, compared to extensive culture. - The **level of investment required is higher** than the extensive method, and as a result, **yields are higher**. - Stocking rate of **5 to 9 fish per square meter**. - Combination of **fertilizer application** and **supplemental feeding**. **Intensive Culture** - This method of culture is the **most complicated way of growing fish**. - The stocking rate is usually very high (**10 fish per square meter and above**). - Combination of **fertilizer application** and giving large amounts of **supplemental feeds**. - **Water exchange** must be done regularly and **mechanical aerators** may be needed to increase the dissolved oxygen level. - This requires a **high level of investment**, but **yields are much higher** than the semi-intensive culture method. **Systems/Structures Utilized** - **Ponds** - **Cages** - **Pens** - **Tanks** - **Raceways** **[METHODS IN CULTURE]** **Pond Culture:** - A pond is an **earthen**, or sometimes **concrete**, impoundment that holds water. - Pond culture is perhaps the **simplest way of practicing aquaculture**. - Most of the aquaculture production in the world is carried out in ponds. - Earthen ponds are the most widely used structures, mainly due to their relatively low cost. **Cage Culture:** - Cage culture is the **practice of rearing fish in cages**. - It can be applied in existing bodies of water that cannot be drained or seined and would otherwise not be suitable for aquaculture. - These include lakes, large reservoirs, farm ponds, rivers, cooling water discharge canals, estuaries and coastal embankments. - Cages have a **rigid framework**, and a **bag suspended below the water surface**, in which the culture species are retained. - The upper surface is provided with **flotation devices**, which can be manipulated to raise or lower the cage in the water. **Pen Culture:** - Pens are similar to cages, except that the **species is allowed to access the bottom of the water body**. - Pens are generally built in large open waters such as lakes, reservoirs and rivers. - However, **waters** used for pen culture are **relatively shallow** when compared with cage culture, and usually possess a medium to high level of dissolved nutrients. - Fish therefore have access to natural food. **Raceway Culture:** - A raceway is a long, narrow rectangular trench in which **water is flushed through continuously**. - If the land is sloping, a series of raceways can be constructed, linked to each other end to end, one unit flowing into the other, and separated by filters. - **Oxygen is added** to the water by the splashing action as water exits one cell and drops into the other. - This high rate of water movement gives raceway systems distinct advantages over the other culture systems. **[POND PREPARATION]** - The objective of pond preparation is to provide the aquaculture species to be stocked with a grow-out environment having **optimal environmental conditions**, **free of diseases** and their vectors, **without predators and competitors**, as **stress-free** as possible, and with **ample supply of adequate food organisms**. - Pond preparation **provides the farmer with a mechanism to control the pond bottom environment** and minimize animal stress, and promote desirable natural primary productivity. - Routine pond preparation involves several steps: 1. 2. 3. 4. 5. 6. 7. 8. **POND PREPARATION - Draining** - Open all water inlet/outlet gates, **quickly drain the pond as completely as possible** and flush vigorously the internal drain canals to resuspend and **flush out as much as accumulated sludge as you can**. - This should be done before the sludge dries out and solidifies. - - Heavy chains and rakes are dragged along, or people can walk along the internal canals to resuspend sludge material. - Sludge removal is critical, because **if left undisturbed**, it will become anaerobic, reduced sediment which will **generate toxic metabolites** such as **methane**, **hydrogen sulfide**, **ammonia**, nitrite, ferrous iron and others, **negatively affecting water quality** and **production** during the next production cycle. - Low areas with standing water should be drained by pumping, or digging drainage ditches, if possible. **POND PREPARATION -- Drying** - The next step is to allow the pond to partially dry for varying periods of time **(\~1-3 weeks, max. 1 month**). - Exposing the pond bottom soil to the sun and air includes the following advantages: - enhance organic matter decomposition by bacteria, - eradicate viruses, bacteria, and fungi, - eradicate eggs, larvae and adults of predators and competitors, and - dry out undesirable filamentous algae. - The **rate of decomposition is greatest at a soil pH of 7.5-8.5**, so in acidic pond soils many farmers add lime products to enhance soil pH and hence increase organic matter decomposition. - Pond drying out and disinfecting may be, to date, the **most effective method in controlling viral epidemics** in shrimp production ponds. - **If disease epidemics have occurred** on site within the last production cycle a **pro-longed dry out of two to three months** is recommended. - The pond's surface **should be cracked to a minimum of two inches** (5 cm) during this process, to oxidize the soil eliminating anaerobic conditions. **POND PREPARATION -- pH Mapping** - In acidic soils with low pH (under 7), **mapping of pond bottom pH** should be done promptly **by sampling soil pH** at various stations within the pond, and while the soil has a humidity of around 30%, **in order to calculate lime requirements**. - Once the pond surface is hard enough to walk on, soil pH measurements using standardized procedures are taken to determine lime requirements. **POND PREPARATION -- Tilling** - Tilling **aids in aerating soils that may have anaerobic areas** where organic matter and hydrogen sulfide (toxic to shrimp) accumulate. - **Tilling** or **plowing** the bottom soil **to a depth of 10-20 cm** is optional, depending on condition of bottoms. - This particularly **important in areas of heavy sludge accumulation**, such as internal **canals or areas adjacent to drainage gates**, but it is usually difficult to get heavy equipment into/out of these areas, so specialized equipment has been develop for these areas. - It is also common to **incorporate a nitrogen source such as urea into the soil before tilling**, with the objective of increasing the rate of organic matter decomposition. - Some farmers apply about **50% of the calculated lime requirements during tilling**. - Tilling the surface soil of pond bottoms ensures complete oxidation of lower layers of anaerobic mud. **Why is it needed to scrape the pond bottom?** - It is necessary **to remove, or dry out excess black (sulfuric) mud**, **debris**, **and organic compounds** that accumulate in the surface of the soil since it negatively affects with the water. - Also, certain **viruses and pathogenic bacteria** can be harbored in the mud. - This practice is very important in shrimp farms since shrimp forage and spend most of their time on the bottom. **POND PREPARATION -- Disinfection** - The purpose of disinfection is to **eradicate all stages** (eggs, larvae, juveniles and adults) **of species of fish, crustaceans**, **insects and other predatory and competitor species**. - Many products are commonly used to disinfect ponds before stocking shrimp. - In general, the **use of pesticides is not recommended**, because of their slow biodegradation, and potential to accumulate in sediments and bioaccumulate in the food web. - **Chlorination** is the disinfection method of choice for many farmers. **POND PREPARATION -- Liming** - Ponds may be limed to obtain one or more of the following benefits: 1. Total hardness and total alkalinity are increased, and the **pH buffer system is enhanced**. 2. Liming **neutralizes acid soil conditions**, thus increasing the pH and availability of phosphorus. 3. Liming **adds calcium**, a plant nutrient. If dolomitic limestone is used, **magnesium**, also a plant nutrient is added. 4. Addition of **calcium is directly beneficial to crustaceans.** 5. Liming may serve as a **disinfectant or sterilant** 6. **Decomposition of organic matter** in pond muds **is sped up** 7. Lime **helps to flocculate (settle out) clay particles** in muddy water. **Three types of lime:** 1. **Unslaked lime (CaO)**. This has the fastest reaction and it is **173%** efficiency 2. **Slaked lime Ca(OH)~2~**. Also called hydrated lime because it is composed of hydrogen (H) and Ca compound. This **139%** efficient. 3. **Agricultural lime or dolomitic lime (CaCO~3~)**. This is **100%** efficient **When to lime?** 1. when the pH of water is too low; 2. when the bottom is too muddy or neglected; 3. when the organic matter is too high and there is danger of lack of oxygen; 4. when there is a threat of/or contagious diseases are noticed **[METHODS OF LIMING]** 1. Liming the bottom of a dried pond; 2. Liming the pond water; 3. Liming the water flowing in the pond - Liming **should be spread evenly** as possible over the complete surface either of the pond bottom or of the water. **Computation of the quantity of lime to correct acidity in a given pond:** **Formula:** [\$\\mathbf{A}\_{\\mathbf{L}}\\mathbf{=}\\frac{\\mathbf{\\text{pH}}\_{\\mathbf{d}}\\mathbf{-}\\mathbf{\\text{pH}}\_{\\mathbf{P}}}{\\mathbf{(0.1)(\\%\\ effectivity)}}\\mathbf{x}\\frac{\\mathbf{0.5\\ tons}}{\\mathbf{\\text{ha}}}\\mathbf{\\text{x\\ A}}\$]{.math.inline} *Where*: A~L~ = amount of quantity of lime pH~d~ =desired pH which is usually 6.8 to 7.2 pH~p~ = present/average pond pH \% effectivity = for unslaked lime it is 173%; A = area of pond **SAMPLE PROBLEM:** Pond soil analysis on the fishpond of Mr. Bernardo revealed that the average pH of the 3.5 hectares pond is 6.2. Determine the quantity of unslaked lime, slaked lime and dolomitic lime to be used. **Solution:** For unslaked lime: For slaked lime: For agricultural/dolomitic lime: **Conclusion:** Therefore, we can conclude that the **lower the % effectivity of the lime**, the **higher is the quantity of lime** to be introduced or applied in a given pond. **POND PREPARATION -- Fertilization** **[Productivity]** - This refers to the **rate at which energy/biomass is produced per unit area over a specified period of time** (i.e. kcal/m^2^/year or tons/hectare/year) - **Primary Productivity** -- Autotrophs (aquatic plants, algae) - **Secondary Productivity** -- Heterotrophs (finfish, crustaceans, other consumers) **[How to determine the productivity in water?]** - Through chemical analysis such as: - Chlorophyll Method - Light and Dark Bottle Method (measuring oxygen produced) **[Carrying Capacity]** - The amount of a given activity that can be accommodated within the environmental capacity of a defined area. - In aquaculture: usually considered to be the **maximum quantity of fish that any particular body of water can support over a long period** without negative effects to the fish and to the environment (maximum standing crop). - This can be **increased through fertilization**, **supplemental feeding**, **aeration**, and **maintenance of water quality.** **[Nutrients and Fertilizers: Pond Preparation]** - Drain the pond properly - Dry for 1-3 weeks until soil cracks - Repair gates and dikes; level the pond bottom - Eliminate pests and weeds - **Teaseed** (*Camellia dripisera*) -- Contains 10-15% **saponin** at a rate of 200 kg/ha - **Tobacco Dust** -- Contains **nicotine** -- 15 kg/ha - **Derris Root** -- Contains **rotenone** **[Nutrients and Fertilizers]** - Nutrients are added to aquaculture systems **in order to augment the carrying capacity and increase productivity** - Nutrients are supplied **via the application of fertilizers** (either organic or inorganic) - Major Nutrients - Nitrogen (N) - Phosphorus (P) - Potassium (K) - Fertilizers are used to **increase primary productivity or natural foods in ponds.** - These can be **natural** or **synthetic substances**---plankton and other natural food organisms---added to the aquaculture pond to increase primary productivity. *Why fertilize ponds?* 1. Fertilization increases production of culture species by **increasing biomass of phytoplankton** and subsequent links in the food chain 2. Increased production of pond organisms through fertilization **reduces the cost of supplemental feeding** 3. A growing phytoplankton blooms **helps remove nitrogenous wastes such as ammonia**, other toxic substances, and will tie up heavy metals 4. A healthy phytoplankton blooms helps to **enrich pond waters with dissolved oxygen** 5. A phytoplankton bloom **produces turbidity that helps reduce bird predation** of culture species 6. Fertilization **helps to control submerged aquatic weeds** by encouraging growth of phytoplankton bloom, that shades out rooted vegetation 7. Fertilization may **indirectly control mosquitoes** by controlling weeds **[Two types of fertilizers]:** - **Organic fertilizers** -- these are derived from plant material or animals, which contain a mixture of **organic matter and mineral nutrients**. They are obtained by the conversion of animal manure, post harvest material, or organic waste into compost. - Chicken Manure - Cow dung - Agricultural wastes - **Inorganic fertilizers** - which contain **only mineral nutrients** and **no organic matter**; they are manufactured industrially to be used in agriculture for improving crop production and they can be obtained from specialized suppliers - Single element - Urea (45-0-0) - Superphosphate (0-20-0) - Incomplete fertilizer - Ammonium phosphate (16-20-0) - Complete fertilizer - Triple 14 (14-14-14) **[How to apply (fertilizer, lime and other nutrients?]** - Generally, fill the pond with water at a depth of 60 cm. And then raise the water level to 80 cm after 1 week of applying fertilizer. **[Method]**: - **[Sack method (for organic fertilizers)]** -- Place organic fertilizers in gunnysacks suspended in the water to enable it to dissolve gradually, thus providing continuous supply of nutrients. - **[Platform method (for inorganic fertilizers)]** -- The platform is a table-like structure positioned with its surface horizontal beneath the water surface and is raised by 20-40 cm from the pond bottom. **Factors affecting stocking rate** - **Fish seed** refers to the **fry**, **post-larvae** and **fingerlings** of the species to be cultured, and they are usually obtained from natural waters and hatcheries. - **A fishpond can only support a certain quantity of fish** because of its limited space and the amount of natural food available. - The natural food is **affected** mainly **by** the **soil conditions** and **water quality** of the pond. - This **limit** is usually called the **carrying capacity** (or **maximum standing crop**) of the pond. - It is defined as the **maximum weight of fish stock that can be sustained by a pond** (by either the food produced within the pond or made available to the fish) **without gaining or losing weight**. - The carrying capacity of a pond can be increased by fertilization and/or supplemental feeding. - **[Fertilization increases] the production of plankton or benthic algae** as fish food. - **[Supplemental feeding] compensates for nutrients which are in short supply** in the pond. - **[Aeration and running-water systems] increase the amount of dissolved oxygen** thereby increasing the carrying capacity of a pond. - Take note that an increased carrying capacity of a pond (semi- intensive or intensive systems) **allows higher stocking rates thus higher yield/harvest** **STOCKING METHODS** **[Monoculture]** - Monoculture is the **stocking of a single species in a pond**. - Within the monoculture system, there are several stocking practices that affect pond production like **mono-size stocking**, **multi-stage stocking** and **multi-size stocking** **[Monoculture: mono-size stocking]** - Mono-size stocking is the **stocking of one species of the same size in a pond** and to harvest all the fish at marketable size. - This practice has some disadvantages. - **[If stocking density is too high]**, the fish would be **overcrowded** when they reach adult size. Thus, **growth and survival rates would be reduced** - **[If stocking density is too high]**, the fish would be **overcrowded** when they reach adult size. Thus, **growth and survival rates would be reduced.** **[Monoculture: multi-stage stocking]** - Multi-stage stocking or modular method **involves the stocking of fish of uniform size in progressively larger ponds** as more space is needed. - This method **takes advantage of the growth potential of the fish and their density** can be adjusted as **they are transferred to larger ponds.** - This practice enables the fish farmers to undertake a **continuous cycle of stocking and harvesting.** **[Monoculture: multi-size stocking]** - Multi-size stocking **involves the stocking of different size groups of fish** in the same pond. - Ponds produce a variety of natural food and the **feeding habits of the young and adult fish are often quite different**. - The stocking rate and the total yield of a pond can be increased by stocking different age groups to **more efficiently utilize the forage**. Polyculture =========== - Polyculture is based on the principle that **fertile bodies of water produce a variety of food organisms** and stocking of a variety of species is effective in utilizing all these food organisms. - By stocking different species having complementary feeding habits or that feed in different zones, **this will efficiently utilize** **space and available food in the pond and increase total fish production** **FEEDING AND FEED MANAGEMENT** - **Nutrition** is defined as the sum of the processes by which an animal or plant takes in and utilizes food substances. - It is a **series of processes by which organisms acquire and assimilate food** for tissue growth and replacing worn and damaged tissues. - It is important to note that **cost of feed represents \>50% of variable operating costs**. - In pond aquaculture, the feeding strategies used are: **production of natural food**, **feeding supplementary diet**, **feeding a complete diet**. **[Production of natural aquatic food]** - **Natural food** are found naturally in the pond which includes detritus, bacteria, plankton, worms, insects, snails, and aquatic plants. - **During the early growth stages of the cultured animal and at low stocking density**, the role of natural aquatic food, as the only source of nutrition is very important. - The natural food bases in ponds are: ***lablab*** (a complex of blue- green and green algae, diatoms, rotifers, crustaceans, insects, roundworms, detritus, plankton, and ***lumut*** (fibrous filamentous green algae). - **Organic** or **inorganic fertilizers are periodically applied** as sources of carbon, nitrogen, and essential minerals. - With **sunlight**, fertilizers **enhance the growth of phytoplankton** thereby increasing the natural productivity and hence fish production. **[Feeding a supplementary diet]** - **When stocking density** and standing crop of cultured animals **is increased**, the **natural productivity can no longer support adequate growth** thus supplemental feeds become necessary. - The commonly used supplemental feeds are **rice bran**, **chicken feed**, **breadcrumbs**, **boiled corn**, **cooked cassava**, and **chicken entrails**. - These are **nutritionally incomplete** and would be **inadequate** if used **as the only source of food**. **[Feeding a complete diet]** - **At higher stocking densities** typical of intensive culture, a **complete diet is necessary** to provide the nutrients required by the animal for growth and survival. - Complete diet are feeds that are regularly distributed to the fish in the pond. - They are **made from a mixture of carefully selected ingredients to provide all the nutrients** necessary for the fish to grow well. - Complete diet are **important in the intensive system** of aquaculture. - Since the aim of high level of production is to maximize yield per unit area in a shorter period, highly effective artificial feeds are used. - However, **these feeds are quite difficult to make** on the farm and are **usually quite expensive** to buy **[Why should we feed fish?]** - **Natural foods may not be enough** to give the required growth rate - **More fish may need to be stocked** in the pond than the natural food will support - **Larger fish may be required**, in a short amount of time - It may be **uneconomical to rely on natural food** **[Sampling and record keeping]** - Regular sampling of cultured stocks is essential in order to assess the effectivity of feeding management. - **Sampling** involves weighing or measuring **a representative group** (sub-sample) of animals. - These data can then be **used to determine the total biomass**, and the changes in weight or length from previous sampling data - All sampling methods **should be carefully designed to avoid bias**, and to **minimize any stress on the animals** - To estimate biomass in the pond, tank or cage, fish are sampled by using **a cast or lift net**. - Some useful parameters that must be recorded in the farm: - **Pond** -- Pond number, area, depth - **Fertilizer** -- Source, date of fertilizer applications, type and quality of fertilizer used. - **Animal stock** -- Date of stock, species, behavior, stocking density, average initial weight or length, date of sampling, date of harvest, average final weight or length, kg harvested, weight gain or growth, survival at harvest, size distribution at harvest. - **Feed** -- Date of purchase of feeds, feeding rate and amount, type of feed used, date each feed type is given, feeding frequency, feeding time, feeding location in the pond, presence of left-over feeds, feed conversion ratio. - **Water quality** -- Secchi dish reading ( water transparency), water exchange rate, salinity, dissolved oxygen level, date of water change, water temperature, water color, time and duration of paddlewheel operation if used. - **Others --** Diseases or abnormalities of stocks, predators in pond, water conditions during the growing cycle, unusual events, costs of inputs, investment returns. **[Feeding Ration]** - **Feed ration** is the amount of feed given per individual or per group of individuals. - The **amount of the daily feed ration**, and the **frequency** and **timing of feeding** are important factors affecting growth and feed conversion. - **Each cultured species has a dietary feeding rate optimal** for growth and feed efficiency. - **Feeding rate** refers to the total quantity of feeds to be given daily to the fish usually expressed as percentage of the total weight of fish present (e.g. 10% of BW). - Fish **lose weight when their feed intake falls below the required level** for maintenance - The formulas to compute for average body weight, survival rate, and daily feed ration are:  **[Feed application methods]** - Manually broadcasting feeds in the middle of a big pond **requires the use of a small banca**. - Mechanical means of partially replacing hand **automatic feeders** which can be set to release controlled amounts of feed when activated, and **demand feeders** which can release a few pellets each time a triggering mechanism is bumped by the fish. - Feeding trays are used either to monitor actual feeding or to serve as feeding areas.