Japan 高校（専門学科）1〜3年 Fisheries and Marine

Chapters: 22

1. Basic Fisheries and Marine Science

Outline of the sea · Outline of fisheries and marine industries · Basic practice

Oceans: The Sea Floor, Moving Water and Life – Oceans cover about 71% of the Earth. Their floor has a shallow continental shelf, a steep slope, a deep plain, underwater ridges and very deep trenches. Water moves in three ways: waves (made by wind), tides (made by the Moon's pull) and currents (rivers in the sea, warm and cold). Oceans give fish, salt, oil, gas and trade routes, and millions of people earn their living from them. Cyclones and tsunamis are ocean hazards; early warning saves lives. International rules (UNCLOS) set how far a country's sea rights reach: 12 nautical miles of territorial sea and a 200-mile Exclusive Economic Zone.
Fisheries and Aquaculture: From Sea to Plate – Fisheries means catching fish and other water animals from the wild (capture fishing), while aquaculture means farming fish, shrimp, shellfish or seaweed. Most wild fish are caught over shallow continental shelves and in areas of upwelling, where nutrients feed plankton. Fish then pass through a chain: harbour and ice, processing (cleaning, freezing, drying, canning), cold storage and distribution to markets or export. When the catch is larger than the stock's natural regrowth, the stock collapses: overfishing. Good management uses catch limits, closed seasons, mesh-size rules, protected areas and responsible aquaculture.
Basic Fisheries Practice: Collect, Rear, Process and Work at Sea – Basic fisheries practice has four jobs. Collecting: a net keeps animals bigger than its holes. Rearing: fish need at least 5 mg of oxygen per litre; below 3 mg they are in danger. Processing: cold fish stay fresh much longer, so chill at once. Sea work: check weather, wear a life jacket, and keep small boats in harbour in big waves.

2. Research Project

Investigation, research and experiments · Making works · Practice at industrial sites · Obtaining vocational qualifications

Making Things: From Idea to Prototype – To make a product, we plan it, choose materials, measure and mark, cut, join, finish, test and then improve. The first working model is called a prototype. Each step uses the right tool, used safely. Testing shows what must change, and a good maker repeats the loop until the product works well.

3. Comprehensive Practice

Ocean fishing practice · Ocean engineering practice · Telecommunications practice · Resource enhancement practice · Seafood processing practice · Other fisheries and marine practice

Ocean Fishing Practice: A Day at Sea from Harbour to Ice Box – A fishing trip follows six steps: check boat, crew and weather; steer with compass and GPS; find the shoal with an echo sounder (depth = 1500 × time ÷ 2); shoot the net to the shoal depth; haul it in; and put the catch on ice at once. Record position, depth and catch. Safety comes first at every step.
Ocean Engineering Practice: Floating, Water Pressure, Mooring and Rust – Four ideas help build things for the sea. A block floats if its density is below sea water (about 1025 kg/m³). Pressure grows with depth: P = P0 + ρgh, about +100 kPa every 10 m. A moored boat needs rope at least 3 times the depth. A zinc block rusts first, so the steel is saved.
Ship Radio Practice: Range, Morse Code, Distress Calls and Wavelength – Boats talk to the shore by VHF radio, near 156 MHz. VHF goes in straight lines, so range ≈ 4.12 × (√h1 + √h2) km with antenna heights in metres. Morse sends letters with dots (1 unit) and dashes (3 units); SOS is three dots, three dashes, three dots. A Mayday call has five parts in order. Wavelength = 300 ÷ frequency in MHz, in metres.
Resource Enhancement Practice: From Hatchery to Sea – Resource enhancement means helping wild fish stocks grow back. In a hatchery we keep parent fish, collect eggs, raise larvae and juveniles in clean tanks, tag some and release them at a good size. Each stage loses some fish, so we count, feed carefully and keep the water clean.
Seafood Processing Practice – Fish spoil quickly because germs grow fast in the warm, wet, protein-rich flesh. Seafood processing keeps fish safe: chill at once, wash and clean with clean tools, cut into fillets, then keep by drying, salting, cooking or canning. Cleanliness and cold are the two big rules.
Other Fisheries and Marine Practice: Testing the Water – Fish live in their water, so we test it often. Four easy tests are temperature, dissolved oxygen, salt (salinity) and clarity (with a Secchi disc). Warm water holds less oxygen, sea fish need the right amount of salt, and green water means lots of tiny plants. Records of these numbers keep fish healthy.

4. Marine Information Technology

Information technology in fisheries and marine fields · Information communication and design in fisheries and marine fields · Computers and programming · Networks and use of data · Applying IT in fisheries and marine fields

Information Technology in Fisheries and Marine Work – Boats and ocean workers use information technology to see what the eye cannot. Sonar sends a sound pulse down and times the echo: depth = 1500 × time ÷ 2. GPS satellites give position, radio and satellites send data to shore, and sensors record temperature and weather. Because data is valuable, people must keep passwords and fishing spots safe and use information fairly.
Digital Media: How Pictures, Sound and Video Become Numbers – Digital media is any picture, sound, video or animation stored as numbers on a computer. A raster image is a grid of pixels, each stored as red, green and blue values from 0 to 255. Vector graphics store shapes as maths, so they stay sharp at any size. Video and animation are many frames shown quickly. File size grows with resolution and colour depth, so we use compression. When we make or share media we must respect copyright, licences and people's image rights, and work safely and critically.
Computers and Programming: How Computers Work and How We Instruct Them – A computer takes input, processes it with the CPU using memory, and gives output; storage keeps files and the operating system manages everything. All information (numbers, letters, pictures, sound) is stored as bits, 1s and 0s, in groups of 8 called bytes. To solve a problem we first write an algorithm (clear steps using sequence, decision and repetition) and then a program, which is the algorithm written in a programming language. Computers also share information through networks, in small packets, and can run models and simulations to test ideas safely.
Computer Networks and How the Internet Works – A network is a group of devices linked to share data. Each device has an IP address. Data is cut into numbered packets. Routers pass each packet hop by hop towards its address, and TCP puts the packets back in order. DNS turns a website name into an IP address. Clients ask, servers answer. Firewalls, passwords, updates and encryption keep a network safe.
Using IT in Fisheries and Marine Work – Modern ships and fishers use information technology (IT): sonar finds fish by sound echoes, GPS gives position, radar and AIS avoid collisions, buoys and satellites measure the sea, and shore data centres join all this data to give advice. Depth from an echo is depth = speed of sound x time / 2.

5. Fisheries and Marine Science

Ocean and daily life · Ocean science · New developments in fisheries · Inquiry activities on the ocean

Fisheries and Aquaculture: From Sea to Plate – Fisheries means catching fish and other water animals from the wild (capture fishing), while aquaculture means farming fish, shrimp, shellfish or seaweed. Most wild fish are caught over shallow continental shelves and in areas of upwelling, where nutrients feed plankton. Fish then pass through a chain: harbour and ice, processing (cleaning, freezing, drying, canning), cold storage and distribution to markets or export. When the catch is larger than the stock's natural regrowth, the stock collapses: overfishing. Good management uses catch limits, closed seasons, mesh-size rules, protected areas and responsible aquaculture.
Oceans: The Sea Floor, Moving Water and Life – Oceans cover about 71% of the Earth. Their floor has a shallow continental shelf, a steep slope, a deep plain, underwater ridges and very deep trenches. Water moves in three ways: waves (made by wind), tides (made by the Moon's pull) and currents (rivers in the sea, warm and cold). Oceans give fish, salt, oil, gas and trade routes, and millions of people earn their living from them. Cyclones and tsunamis are ocean hazards; early warning saves lives. International rules (UNCLOS) set how far a country's sea rights reach: 12 nautical miles of territorial sea and a 200-mile Exclusive Economic Zone.
Inquiry Activities on the Ocean – An inquiry is a way of finding answers by yourself. Steps: ask a question, plan a fair test (change one thing, keep others same), measure, record in a table or graph, find the pattern, and share with evidence. Example: sea temperature falls as depth increases.

6. Fisheries

Fisheries and marine environment · Fishery resources and fisheries management · Fishing technology · Foundations of fishery production · Fishery business management

Fisheries and the Marine Environment – Fisheries are the work of catching or raising water animals for food and income. The sea feeds fish through a food chain that starts with sunlight and plankton. Rich fishing grounds appear where nutrients rise from the deep (upwelling) or where shallow shelves catch the sun. Surveys with echo sounders, nets and water tests find the fish. Clean water, protected habitats and sensible catches keep the sea productive.
Fishery Resources and Fisheries Management – A fish stock is all the fish of one kind in one sea area. It grows back each year, so it is a renewable resource. A stock stays healthy when the yearly catch is not bigger than the yearly growth. A catch above growth shrinks the stock (overfishing) until it can collapse. Management uses catch limits, closed seasons, mesh-size and gear rules, protected nursery areas and stock monitoring.
Fishing Technology – Fishing gear catches fish in different ways: hooks (line), nets that tangle fish (gillnet), nets that surround them (purse seine) and nets that scoop them while towed (trawl). The mesh size decides which fish are kept. Gear is made from strong, light synthetic fibre (nylon, polyethylene) with floats and sinkers. Boats use winches, echo sounders and radio, and keep the catch fresh with ice or refrigeration. Enhancement such as hatchery release and artificial reefs helps stocks.
Foundations of Fishery Production – Fishery production is more than catching. Laws and licences say who may fish and where, and the sea is shared with other countries through the 200 nautical mile economic zone and treaties. Weather, price and fish-location information guide every step. Fish travel a chain: boat, port market, processing, cold store, trade and shop. Because fish spoil fast, quality and safety depend on keeping them cold, clean and checked (for example by HACCP).
Fishery Business Management – A fishery business sells what it catches or grows and pays for fuel, crew, gear and repairs. Income = quantity sold × price. Profit = income − total cost. Owners choose a form of organisation (sole owner, partnership, co-operative or company), keep accounts and plan the season. Efficiency means cutting waste (fuel, spoilage), selling well (co-operative, processing) and fishing in a way the stock can support.

7. Navigation and Instruments

Overview of navigation · Navigational information · Instruments and navigation · Voyage planning · Maritime traffic laws · Maritime English

Overview of Navigation: Finding the Way at Sea – Navigation means knowing where a ship is and steering it safely to where it wants to go. A navigator uses a course (direction from north), distances in nautical miles, speed in knots and the rule distance = speed × time. Methods are coastal (landmarks), radio (satellites, radar), celestial (stars and sun) and dead reckoning.
Navigational Information: Charts, Aids, Currents and Tides – Before and during a voyage a navigator uses charts (depths, hazards), navigational aids (lighthouses, buoys, beacons), tide tables and current information. Depth of water = charted depth + height of tide. Currents push the ship sideways (set and drift) and must be allowed for.
Instruments and Navigation Methods at Sea – Basic instruments: compass (direction), log (speed), echo sounder (depth), clock and chronometer (time). Position is fixed by coastal navigation (bearings of landmarks), radio navigation (GNSS satellites, radar) or celestial navigation (sextant sights of Sun and stars). Two or more position lines that cross give a fix.
Voyage Planning: From Port A to Port B Safely – A voyage plan covers the whole trip from berth to berth. Four stages: appraisal (collect information), planning (draw the route with waypoints, legs, speed, time, fuel, tides and safety margins), execution (sail the plan) and monitoring (check position and change the plan if needed). Time = distance ÷ speed.
Maritime Traffic Laws: Rules of the Road at Sea – Ships follow international collision rules (COLREGs) that every country writes into its law. Head-on: both alter course to starboard. Crossing: the ship that has the other on her starboard side gives way and the other stands on. Overtaking: the overtaking ship keeps clear. Busy waters have traffic lanes and ports have their own rules on speed, fairways and anchoring.

8. Ship Operation

Overview of ships · Ship equipment · Ship's business · Marine weather · Ship handling · Safety and hygiene on board · Seafarer, ship and marine laws

Overview of Ships – A ship is a floating steel building. It floats because the water it pushes aside weighs as much as the ship (Archimedes' principle). Ships have a hull (bow, stern, keel, deck), come in many types (cargo, tanker, fishing, passenger) and follow international safety rules such as the load line.
Ship Equipment – A ship is a floating workshop and home. Its equipment has six groups: steering, engine and radio; mooring and cargo gear; stores; safety and sanitary items; fishing gear; and freezing and cold storage. Each group does one clear job.
Ship's Business: Running a Ship Day by Day – Running a ship means five jobs: organising the crew and their duties, caring for the hull, docking the ship for inspection, keeping in touch by radio, and keeping the ship safe by watching all the time.
Marine Weather – Marine weather is the weather over the sea. Wind blows from high pressure to low pressure. Stronger wind makes higher waves. Warm moist air over a cold sea makes fog. A typhoon is a spinning storm with very low pressure in the middle. Near Japan the winds change with the seasons.
Ship Handling – Ship handling means controlling a ship's speed and direction safely. The rudder turns the ship, but a ship is heavy and keeps gliding, so it turns slowly and stops slowly. Wind and waves push it sideways. In heavy weather the crew slow down and meet waves from the bow. In an emergency, quick, calm, trained steps save lives.
Safety and Hygiene on Board – A ship is far from help, so crew must prevent accidents, put out fires fast, give first aid, and keep the ship clean. Remove one side of the fire triangle (fuel, heat, air) to stop a fire. For a person who is not breathing, give 30 chest presses and 2 breaths. Cleaning and disinfection stop germs, rats and insects.
Seafarer, Ship and Marine Laws – A ship sails through many places, so its rules come from many levels. International treaties made through the IMO and the UN set the base: STCW and MLC for seafarers, SOLAS and the Load Line rules for safety, MARPOL for pollution, health rules for hygiene, and UNCLOS for who controls which part of the sea. Each country turns these treaties into its own laws and checks ships in its ports.

9. Marine Engines

Overview of heat engines · Internal combustion engines · Propulsion systems · Fuels and lubricants · Auxiliary machinery · Boilers and refrigeration equipment · Ship operation and security

Heat Engines – A heat engine is a machine that turns heat into mechanical work. Fuel burns and releases heat Q = q × m, where q is the heat value (heat of combustion) of the fuel and m is its mass. Hot gas expands and pushes a piston or spins a turbine. A four-stroke engine repeats intake, compression, power and exhaust. Only part of the heat becomes useful work; the rest leaves as waste heat. Efficiency η = W ÷ Q × 100%. Engines also release CO₂ and other gases that harm the air and warm the planet.
Ship Propulsion Systems – A ship moves because its engine turns a shaft, the shaft turns a propeller, and the propeller pushes water backward, so the water pushes the ship forward. A rudder at the stern steers by bending the water stream. Other systems (twin screws, controllable pitch, azimuth pods, water jets) do the same job in different ways. Needed power grows roughly with the cube of speed, so going slower saves a lot of fuel.
Fuels and Lubricants – Ship engines burn fuel oil: thick, cheap heavy fuel oil (HFO) that must be heated and cleaned, or thinner distillates like marine diesel (MDO) and gas oil (MGO). Important fuel properties are heat value, viscosity, flash point and sulphur. Lubricating oil puts a thin film between moving metal parts. The film cuts friction and wear, carries heat away, cleans, seals and protects from rust. Oil gets thinner when hot and thicker when cold, so temperature matters for both fuel and lube oil.
Auxiliary Machinery on Ships – The main engine drives the ship, but many helper machines keep it running: pumps move water, oil and fuel; hydraulic systems turn small pushes into big forces for cranes, winches and steering; fresh-water generators boil sea water at low pressure and condense it into drinking water; and pollution-control equipment such as the oily-water separator cleans waste before it leaves the ship. Each one uses a simple physics idea: pressure, Pascal's law, boiling and condensing, or floating by density.
Boilers, Refrigeration and Air-Conditioning Equipment – A boiler burns fuel to heat water into steam at high pressure; a gauge and a safety valve keep it safe. A refrigerator or air conditioner does not make cold; it moves heat. A refrigerant circles through a compressor, condenser, expansion valve and evaporator, taking heat in at the cold side and giving it out at the hot side.
Ship Operation and Security – A ship is run by a crew in departments (deck, engine, catering) under the captain. Its hull is split into watertight compartments, so one flooded space does not sink it. Fixed equipment, safety drills, international sea rules (such as red port and green starboard lights) and clear standard English on the radio keep everyone safe.

10. Machine Design and Fabrication

Overview of machine design and fabrication · Machine design · Mechanical drawing · Machine materials · Machine shop practice

Mechanical Engineering: How Machines Are Designed and Made – Mechanical engineering is the branch of engineering that designs, makes and looks after machines: anything with moving parts that uses forces and energy, from a bicycle to a jet engine. Mechanical engineers use physics (forces, motion, energy, heat), materials science and maths. Key ideas: mechanisms change motion and force (gears, levers, cranks), energy is converted (heat to motion in engines, electricity to motion in motors), parts must be strong enough (stress, bending, safety), and parts are made by machining, fitting and assembly to exact sizes with tolerances. Mechatronics adds electronics, sensors and computer control.
Machine Design: Fasteners, Shafts and Gears – A machine is built from small standard parts called machine elements. Fasteners (bolts, nuts, screws, rivets, pins) join parts. Shaft elements (shafts, keys, couplings, bearings) carry turning motion. Gears, belts and chains pass motion on; gear ratio = teeth on driven gear / teeth on driver gear.
Machine Drawing: Making and Reading Detail Drawings – A machine drawing is an exact picture of one part, made so a factory can build it without asking any questions. A detail (working) drawing shows the views of the part, section views for hidden insides, every size (dimension), how much each size may vary (tolerance), the surface finish, the material and a title block.
Materials and Their Properties: Why Things Are Made of What They Are – Every product is made from materials chosen for their properties. The main families are papers and boards, timbers, metals, polymers (plastics) and textiles. Physical properties describe what a material is like (density, conductivity, how it reacts to heat and water). Working properties describe how it behaves when we use or shape it (strength, hardness, toughness, elasticity, plasticity, malleability, ductility). Materials come from natural sources such as trees, ores and crude oil, and are sold in standard stock forms like sheets, bars, tubes and planks. A designer picks a material by matching its properties to the job, and also thinks about cost, availability, looks and the environment.
Machine Shop Practice: How Metal Becomes a Part – A machine shop turns raw metal into a finished part with five groups of jobs: casting and forging (shaping), sheet-metal work (bending flat sheet), welding and cutting (joining and separating), machining (removing metal with a tool for exact size), and hand finishing and assembly (filing, fitting, bolting). Every job has its own safety rules.

11. Electrical Theory

Basics of electric circuits · Electricity and magnetism · Semiconductor devices and electronic circuits · Electrical machines · Electrical measurement and automatic control · Distribution and electrical work

Electric Current, Potential Difference and Electric Circuits – Electric current is the rate of flow of charge, I = Q/t, measured in amperes with an ammeter joined in series. Potential difference is the work done to move a unit charge between two points, V = W/Q, measured in volts with a voltmeter joined in parallel. Charge flows only in a closed circuit.
Electricity and Magnetism – Electric charge and magnets are two sides of one idea. Rubbed objects hold static charge; magnets have poles and a field; a current makes a magnetic field; and a changing magnetic field makes a current (electromagnetic induction). Motors, generators and transformers all use these four steps.
Semiconductors and the p-n Junction Diode – A semiconductor has a small energy gap (about 1 eV), so a little heat frees some electrons. Pure silicon is intrinsic (electrons = holes). Adding a 5-valence atom makes n-type; a 3-valence atom makes p-type. Joining p and n makes a junction with a depletion layer and a barrier (about 0.7 V for Si). The diode conducts in forward bias, almost not in reverse bias, so it can change AC into one-way DC (rectifier).
Electrical Machines: Generators, Motors and Transformers – Electrical machines change energy from one form to another. A generator turns motion into electricity and a motor turns electricity into motion, both using magnets and coils. A synchronous machine spins exactly with the magnetic field (Ns = 120f/P). An induction motor spins slightly slower (slip). A DC machine uses a commutator. A transformer changes voltage using Vs/Vp = Ns/Np. Emergency supplies (battery and engine generator) keep power on when the mains fails.
Electrical Meters, Measurement and Automatic Control – Electrical meters show a quantity on a scale. An ammeter joins in series and has very low resistance; a voltmeter joins in parallel and has very high resistance. Measurement means comparing with a standard and knowing the error. Automatic control lets a machine hold a value by itself: an open-loop system never checks the result, a closed-loop system uses a sensor and feedback to correct the error. Examples are thermostats, motor speed control and water-level control.
Power Distribution and Electrical Work in Ships and Factories – Distribution carries electricity from the source (generator or grid) to many loads. A main switchboard receives the three-phase supply and sends it through feeders, each with a breaker or fuse. Transformers give the right voltage (for example 440 V down to 230 V). Ships and factories use the same ideas: separate circuits for power and lighting, protection against overload and short circuit, and an earth wire. Electrical work means installing, testing and repairing this system safely.

12. Mobile Communication Engineering

Overview of mobile communication · Radio communication equipment · Microwave circuits and antennas · Radio-wave propagation · Electronic navigation equipment · Applied electronic measurement

Radio, TV and Mobile Phones: How Signals Travel – Radio, TV and mobile phones send information with radio waves. Sound and pictures are turned into a small electric signal. The signal rides on a strong carrier wave from a tower. A receiver tunes to one frequency and turns the signal back into sound and pictures. Mobile networks split land into cells, each with its own tower.
Radio Communication Equipment – A radio transmitter has an oscillator (makes the carrier), a modulator (adds the message) and a power amplifier, then an antenna. A receiver has an antenna, a tuner, a detector and a speaker; a superheterodyne receiver first mixes the signal down to a fixed intermediate frequency. Microwave links use dishes in straight lines. Ships carry distress radios (VHF, DSC, EPIRB, SART) for emergencies.
Microwave Circuits, Antennas and Feeder Lines – An antenna changes an electric signal into a radio wave and back. Its size is tied to the wavelength: a half-wave dipole is λ/2 long. Antennas differ in their radiation pattern: whip and dipole spread power around, Yagi and dish aim it in one direction (more gain). A feeder line (coax, twin-lead, waveguide) carries power between radio and antenna. Microwave circuits (waveguide, stripline, resonators, couplers, circulators) handle signals of 1 to 30 GHz and above.
Radio-Wave Propagation – Radio waves travel in three main ways. Ground waves (below about 2 MHz) follow the ground. Sky waves (about 2 to 30 MHz) bend back from the ionosphere and can reach very far. Space waves (VHF and above) go in straight lines and are limited by the horizon, d ≈ 4.12(√h1 + √h2) km. On the way waves can be reflected, refracted, diffracted, absorbed or scattered, and the signal can fade because of the changing ionosphere and multipath.
Electronic Navigation Equipment: Radar, Satellite Navigation, Sonar – Radar sends a radio pulse and measures the time for the echo: distance = c × t / 2. Satellite navigation (GPS, GNSS) measures the distance to at least four satellites from signal travel time and finds position. Sonar sends a sound pulse and times the echo from the seabed or a target: depth = v × t / 2 with v ≈ 1500 m/s in sea water. Other aids include the gyrocompass, speed log, AIS and electronic charts.
Applied Electronic Measurement – To keep radios and cables working, we measure them. An oscilloscope shows a signal against time (f = 1/T). A transmitter is checked for frequency, power and modulation depth. A receiver is checked for sensitivity. Microwave and light losses are counted in decibels (dB). An antenna is tested by field strength, which falls with distance.

13. Marine Communication Technology

Wired communication equipment · Communication laws · Communication English · Transport and communication geography · Practical communication

Wired Communication Equipment – Wired data communication sends bits (1 and 0) as electric or light pulses along a cable. Data is cut into packets, and each packet carries an address. Terminal equipment (phones, computers, modems) sits at the ends; network equipment (switches, routers) moves packets to the right place. Security tools such as firewalls and passwords protect the data. Good connection work means the right cable, the right wire order and tested joints.
Communication Laws – Radio waves are a shared resource, so laws decide who may use which frequency. National radio laws give licences, the ITU Radio Regulations share bands between countries, wired telecommunication laws cover cables and networks, and maritime laws make sure every ship can call for help.
Transport and Communication in the World – Transport moves people and goods; communication moves messages. Roads are best for short, door-to-door trips, and highways join far cities. Transcontinental railways cross whole continents, like the Trans-Siberian. Sea routes carry most world trade, and ship canals like Suez and Panama save long detours. Inland waterways such as the Rhine and the St Lawrence Seaway carry heavy goods deep inland. Air transport is fastest but costly, pipelines carry oil and gas nonstop, and satellites and the internet move information across the world in seconds.
Practical Communication: Sending, Receiving and Operating – In Morse code a dot lasts 1 unit and a dash 3 units; letters are patterns of both. To send, you key the transmitter on and off; to receive, you listen or watch and write down the pattern. Good operating follows a fixed order (call sign, "this is", message, "over"), uses clear spelling with the phonetic alphabet, keeps distress calls on the proper channel and records every contact in a log.

14. Resource Enhancement (Aquaculture)

Overview of resource enhancement · Feed (livestock and fish) · Diseases and pest control · Product safety and environmental measures · Aquatic breeding and biotechnology · Main aquaculture and stock-enhancement techniques · Aquaculture management and laws

Resource Enhancement Practice: From Hatchery to Sea – Resource enhancement means helping wild fish stocks grow back. In a hatchery we keep parent fish, collect eggs, raise larvae and juveniles in clean tanks, tag some and release them at a good size. Each stage loses some fish, so we count, feed carefully and keep the water clean.
Fish Feed and Nutrition – Fish and shellfish need protein, fat, carbohydrate, vitamins and minerals. Baby fish (larvae) need tiny live food such as rotifers and Artemia; grown fish eat compound pellets made from fishmeal, plant meal, oil and vitamins. Good feeding means a low feed conversion ratio (FCR = feed given / weight gained) and clean water.
Fish Diseases and Pest Control – A fish gets sick when a germ (virus, bacterium, fungus or parasite), a weak fish and bad conditions meet. Diseases spread through water, contact and equipment. Farmers diagnose by looking at behaviour and body signs and by lab tests, then control with prevention first (clean water, fewer fish, quarantine, vaccines) and medicine only when needed.
Safe Seafood and Caring for the Water – Farm fish must be safe to eat and the farm must not harm the water. Safety means clean handling, no leftover medicine (withdrawal period), tags that trace each batch, and a cold chain at about 0 to 4 degrees Celsius. Environmental care means controlling feed waste, not putting too many fish in one place (carrying capacity), resting sites, and growing seaweed and shellfish beside fish.
Aquatic Breeding and Biotechnology – Breeders pick the best fish (fast growing, disease resistant) as parents, so each generation is better on average. Biotechnology adds tools: hybridisation, changing chromosome sets (triploid fish cannot breed and grow big), controlling sex, freezing sperm (cryopreservation), DNA markers and gene editing. Response to selection R = h² × S, where h² is heritability and S is the selection differential.
Main Aquaculture and Stock-Enhancement Techniques – Water life is grown in four main ways: marine animals in sea cages, rafts and ponds (fish, shrimp, oysters, abalone), marine plants such as seaweed on ropes and nets, systems used abroad like shrimp ponds, salmon pens and recirculating tanks, and ornamental fish in aquariums. Stock enhancement releases hatchery-raised young into the sea to rebuild wild numbers.
Aquaculture Management and Laws – Aquaculture is farming fish, shellfish and seaweed. A farm earns profit only if income is more than cost, and stocking, feed and water quality must be balanced. Laws and rules (licences, site permits, water and waste limits, disease control, food safety, protected species) keep farms safe for people and nature.

15. Marine Biology

Outline of marine organisms · Marine animals · Marine plants · Plankton · Fishery resource management · Marine organism experiments

Marine Biology: Life in the Ocean – Marine biology is the study of life in the sea. Ocean life is grouped by how it lives: plankton drift, nekton swim and benthos live on the sea floor. Light fades with depth, so food-making phytoplankton live near the surface and feed almost every marine food chain. Coral reefs, mangroves, the open ocean and the deep sea are key marine ecosystems. The sea gives food, medicines and, through desalination, fresh water, but it faces overfishing, pollution and warming.
Marine Animals: Who Lives in the Sea? – Marine animals live in salt water in three ways: swimmers (nekton) like fish and whales, drifters (plankton) like jellyfish, and bottom dwellers (benthos) like crabs, shellfish and starfish. Main groups are fish, mammals, crustaceans, molluscs, jellyfish (cnidarians) and echinoderms.
Marine Plants: Life in the Sunlit Shallows – Marine plants and seaweeds make food by photosynthesis, so they live only where light reaches: near the shore and in the top 200 m. Sea-grass is a true flowering plant with roots. Seaweeds are algae with a holdfast, not roots. Green seaweeds grow shallow, brown in the middle, red deepest.
Plankton: Tiny Drifters of the Sea – Plankton are tiny living things that drift with the water because they cannot swim against currents. Phytoplankton are plant-like and make food using sunlight; zooplankton are animal-like and eat them. Plankton feed almost all sea life and make about half of the oxygen we breathe.
Fishery Resources and Fisheries Management – A fish stock is all the fish of one kind in one sea area. It grows back each year, so it is a renewable resource. A stock stays healthy when the yearly catch is not bigger than the yearly growth. A catch above growth shrinks the stock (overfishing) until it can collapse. Management uses catch limits, closed seasons, mesh-size and gear rules, protected nursery areas and stock monitoring.
Marine Organism Experiments – Marine organism experiments test how sea life reacts to its surroundings. Animal test: a fish breathes faster in warmer water. Plant test: seaweed grows more with more light. Plankton test: tow a net, then count what is in the jar. Always use a fair test (change one thing), a control, repeat the test, and treat animals with care.

16. Marine Environment

Marine environment and humans · Marine industries and environmental conservation · Fishing-ground environment and surveys · Ocean development and environmental improvement · Responding to marine natural disasters

Fisheries and the Marine Environment – Fisheries are the work of catching or raising water animals for food and income. The sea feeds fish through a food chain that starts with sunlight and plankton. Rich fishing grounds appear where nutrients rise from the deep (upwelling) or where shallow shelves catch the sun. Surveys with echo sounders, nets and water tests find the fish. Clean water, protected habitats and sensible catches keep the sea productive.
Ocean Development and Environmental Improvement – People can improve the sea for fishing and living. They build fishing grounds (artificial reefs, seaweed beds, shallow tidal flats), develop waterfronts (breakwaters, quays, fishing ports) and clean the sea (waste-water treatment, oil booms, dredging). Every project must protect the sea life it wants to help.
Responding to Marine Natural Disasters – Tsunamis, cyclones, storm surges and high waves strike coasts and fishing communities. Good response has three parts: understand how disasters affect daily life, keep people safe with warnings, drills and high ground, and protect work and income with strong, sustainable ways of producing food from the sea.

17. Small Vessels

Conduct as a small-vessel operator · Navigation methods · Ship operation · Engines · Handling small vessels · Operating small vessels

Conduct as a Small-Vessel Operator – A small-boat operator, called the master or skipper, is responsible for the boat and everyone on it. Water transport is different from road transport: boats have no brakes, drift with water and wind, and help is far away. So the master checks the boat and weather, carries only the safe load, keeps a lookout, and obeys the rules on speed, safety gear, licences and pollution.
Navigation Methods: How Boats Pass Each Other Safely – To avoid collisions, boats follow shared rules. In open water: meeting head-on, both turn right; in a crossing, the boat that has the other on its right gives way; an overtaking boat keeps clear. In harbours, go slowly and keep right in the channel. In designated sea areas follow the traffic lanes. On rivers and lakes keep to your right bank and follow local rules.
Ship Operation – Running a boat well needs six things: know the hull, deck and fittings; steer with the rudder and engine; read the compass and chart; understand weather and sea; plan the voyage (route, time, fuel, safe harbours); and know how to act in heavy weather so that accidents are avoided.
Small Boat Engines: Handling, Care and Faults – A small boat engine burns fuel to turn a propeller. Good handling means checking fuel, oil, cooling water and the propeller before starting, watching gauges while running, and stopping properly. Care means changing oil, cleaning filters and rinsing the engine. When it fails, stay calm, make the boat safe, then check fuel, filter, cooling and propeller one by one.
Handling Small Boats: Checks, Mooring, Knots and Direction – Handling a small boat means being ready before you leave and calm at the jetty. Check weather, fuel, engine, life jackets and ropes. Moor with bow and stern lines and fenders, and cast off one line at a time. Learn a few knots (cleat hitch, bowline, round turn and two half hitches, reef knot). Find direction with a compass: a bearing is the angle from North, clockwise, from 000 to 359 degrees.
Operating Small Boats: Basic and Advanced Handling – A boat has no brakes. It turns around its middle when the rudder is turned, and it keeps gliding after the throttle is cut. Wind and current push it sideways. Basic handling is steering, speed control, stopping and keeping a lookout. Advanced handling covers person overboard, anchoring, rough weather, narrow channels and poor visibility. Always go slowly near people and other boats.

18. Food Manufacturing

Overview of food manufacturing · Food preservation and processing · Seafood manufacturing · Food manufacturing equipment · Preventing pollution · Management and production control

Overview of Food Manufacturing and Seafood Today – Food manufacturing turns raw food from farms and the sea into safe, tasty, longer-lasting products through steps like washing, cooking and packing. It cuts waste, makes food easy to carry and gives jobs. Food education teaches people to choose safe, balanced food. About half of the fish people eat is now farmed, and about a third of fish is lost or wasted, so using the whole fish and making good products matters for the future.
Food Preservation, Processing and Value Addition – Food spoils when microbes grow in it and when its own enzymes, air, light and pests damage it. Preservation removes what microbes need: water (drying, salt, sugar), warmth (refrigeration, freezing), a mild pH (acids, fermentation) or the microbes themselves (heat, canning, pasteurisation, permitted preservatives). Foods are classed as perishable, semi-perishable or non-perishable, and as minimally, moderately or highly processed. Good post-harvest storage and processing reduce losses and add value, so farmers and food businesses earn more.
Seafood Processing Practice – Fish spoil quickly because germs grow fast in the warm, wet, protein-rich flesh. Seafood processing keeps fish safe: chill at once, wash and clean with clean tools, cut into fillets, then keep by drying, salting, cooking or canning. Cleanliness and cold are the two big rules.
Food Manufacturing Equipment: Boilers and Freezers – A food factory uses machines to heat, cook, cool and freeze food in large amounts. A boiler burns fuel to turn water into steam, and the steam cooks or sterilises food. A refrigeration machine moves heat out of a freezer using a gas that goes round a loop: compressor, condenser, expansion valve, evaporator. Fish is stored at -18 °C or colder.
Pollution: Air, Water, Land and Noise – Pollution is the release of harmful substances or energy into air, water or land faster than nature can remove them. Main air pollutants are particulates, carbon monoxide, sulfur dioxide, nitrogen oxides and ozone; they cause acid rain and smog. Water pollution by nutrients, sewage and toxins causes eutrophication and biomagnification. We reduce pollution by cutting emissions at the source, cleaning waste before release, and the 3Rs.
Management and Production Control – Management means running a business with people, materials, money and information so that it reaches its goal. A simple tool is the Plan-Do-Check-Act circle. Production management plans and controls making the product. Its three aims are Quality (good and safe), Cost (low waste, fair price) and Delivery (the right amount on time). Going faster can lower quality; checking more costs time and money, so managers balance all three.

19. Food Control

Overview of food control · Food components and their changes · Food and microbes · Food control experiments · Food safety management · Food control laws

Overview of Food Control – Food control is the set of rules, checks and records that keep food safe, honest and of good quality from the sea or farm to your plate. Governments make laws and inspect, companies run their own checks, and shared standards such as Codex help countries agree. Rules grew step by step: local market rules, first food laws after cheating was found in the 1800s, world standards from the 1960s, and today HACCP and tracing food back to its source. No single check is perfect, so many checks together work best.
Food Science: The Chemistry of What We Eat – Food science studies what food is made of and how it changes from farm to plate. Food contains carbohydrates, proteins, fats, water, vitamins and minerals. Cooking changes them: heat unfolds proteins (denaturation), starch swells in water (gelatinisation), and dry heat browns food through the Maillard reaction and caramelisation. Microbes ferment food into bread, curd and pickles, but can also spoil it. Processing, preservation and safe temperatures keep food safe and nutritious for a growing world population.
Food and Microbes, and How to Learn by Project – Microbes (bacteria, yeast and moulds) are in and on all food. Helpful ones make curd, bread, cheese, idli and pickles. Harmful ones spoil food or cause illness. In project learning you pick a question, plan a fair test, do it, check the results and share what you found.
Food Control Experiments – Food labs follow safe habits, measure carefully and write every reading. A chemical test such as titration finds how much acid is in food. A microbe test dilutes the sample and counts colonies on plates to give CFU per gram.
Food Safety Management – A food factory prevents harm with clean habits and a plan. It separates raw and clean areas, washes hands, finds hazards, controls them at critical points such as cooking at 75 °C (HACCP), and uses food additives only in small, legal amounts that are shown on the label.
Food Control Laws – Food laws protect buyers. Safety laws say food must not harm. Standards laws set limits for what is inside, such as maximum water in a dry food. Labelling laws say what the pack must tell you: name, ingredients, allergens, use-by date and weight. Inspectors can stop, recall and fine.

20. Fishery Products Distribution

Overview of fishery distribution · Distribution of fishery products · Distribution technology and management · Fishery product distribution system · Marketing of fishery products · Distribution laws and intellectual property

Food Distribution, Storage and Logistics – Food reaches us through a distribution chain of producers, collectors, wholesalers, retailers and delivery. Along the way it needs the right storage (dry, cool or cold chain), transport with tracking by information systems, quality checks, and, for trade between countries, import and export steps. The aim is food that is safe, fresh and affordable.
Distribution Channels: How Products Reach You – A distribution channel is the path a product takes from producer to consumer. Direct channels have no intermediaries; indirect channels use wholesalers and retailers, who add services and a margin. The internet lets firms skip intermediaries (disintermediation) but new ones appear. Firms choose intensive, selective or exclusive coverage and, because shoppers move between online and physical outlets, link all channels in an omnichannel strategy.
Marketing Management – Marketing means finding out what buyers need and meeting that need in exchange for value, at a profit. It has many functions (research, planning, branding, labelling, packaging, pricing, promotion, distribution, service) and five philosophies (production, product, selling, marketing, societal). The marketing mix is the 4Ps: product (with branding, labelling, packaging), price (shaped by cost, demand, competition, government rules, objectives and marketing methods), place (channels and physical distribution) and promotion (advertising, personal selling, sales promotion, public relations).
Distribution Laws and Intellectual Property – Laws protect people when food is sold. For fish, the main rules cover hygiene and safety, labels and traceability, keeping the cold chain, and licences for traders and markets. Intellectual property (IP) protects what the mind creates: patents for inventions, trademarks for brand names, copyright for writing and pictures, designs for shapes, and place-name rights for regional products. Rules differ by country, so check your own country's law.

21. Diving

Overview of diving · Diving environment · Physiology of diving · Diving equipment · Diving techniques · Diving laws and regulations

Overview of Diving – Diving means going under water for work, food, science or fun. People first held their breath, then used air trapped in a bell, then air sent by a hose to a helmet, and finally air carried in a tank (scuba). A diver must be healthy, able to swim and calm. The main types are breath-hold, scuba, surface-supplied (helmet or full-face mask) and saturation diving for very deep work.
The Diving Environment – Under water the world changes. Pressure rises by about 1 atm for every 10 m, so air shrinks (Boyle's law). It gets colder and darker, and red light vanishes first. Things look closer, and sound travels fast so direction is hard to tell. Buoyancy decides if a diver floats or sinks. Currents can push divers, and some sea animals can sting or bite.
Physiology of Diving – Water pressure acts on the air spaces of the body: ears, sinuses, mask and lungs. Divers must equalise their ears and never hold their breath when rising. More nitrogen dissolves in the blood at depth, so divers rise slowly or it forms bubbles (decompression sickness). Other risks are nitrogen narcosis, cold and tiredness. First aid: get the diver out, check breathing, give oxygen, keep them lying and warm, and call for help.
Diving Equipment – Scuba gear lets a diver carry air: tank, regulator, buoyancy vest (BCD), gauges, mask, fins, wetsuit and weights. Helmet-type diving sends air by hose from the surface to a hard helmet, with a phone line and a lifeline. A full-face mask covers the eyes, nose and mouth and also takes air from the surface or a tank. Other tools are torches, knives, cutting tools and communication sets.
Diving Techniques – A diver needs air, a safe way down, a slow way up and a plan for the work. Air comes from the surface by a hose or from a cylinder on the back. Pressure rises by about 1 bar every 10 m, so air shrinks going down and swells coming up. Rise slowly, never hold your breath, and work with a partner and clear signals.
Diving Laws and Regulations – A working diver is protected by three layers of rules. A general workplace safety law makes the employer responsible for safe work. Special high-pressure work rules cover air, gear, dive time tables, partners and records. Fisheries laws say what may be caught, where and when. Rules differ by country, so always check the local law.

22. Marine Sports

Use of the sea and environmental conservation · Fishing (angling) · Leisure diving · Marine leisure · Safety guidance and management

Use of the Sea and Environmental Conservation – The sea gives food, transport, energy, salt, jobs and fun. If we take too much or pollute it, the sea cannot recover. Careful use means catching less than the fish can regrow, sharing space between users, and protecting key places such as reefs, mangroves and breeding areas.
Fishing (Angling) – Angling catches fish one at a time with a rod, line, float, sinker, hook and bait. The float shows a bite, the sinker takes the bait down, and the bait must sit at the depth where the fish swim. Sea fishing deals with waves, tides and strong fish. River fishing deals with current. Follow local rules, size limits and safety.
Leisure Diving – Leisure diving is diving for fun. Snorkelling means floating on the surface and breathing through a tube. Skin diving (breath-hold diving) means a short dive on one breath, with mask and fins. Scuba diving uses an air cylinder so you can stay under longer. All three need training, a buddy and respect for the sea.
Marine Leisure – Marine leisure means fun and sport on the sea: sailing, canoeing, kayaking, surfing and more. Safe fun needs three things: know the sea rules, read wind, waves and tide, and use the right kit. A sail turns wind into push; a paddle pushes water back so the boat moves forward.
Safety Guidance and Safety Management – Safety guidance means teaching people the rules and skills before an activity. Safety management means organising things so accidents are less likely: check equipment and weather, keep a head count, plan for emergencies and review what happened. Guidance is about people; management is about the whole system.