Specified Skills
Educational Textbook for the Fishing Industry Skills Proficiency Test (Aquaculture)(General, Safety)

Japan Fisheries Association(First Edition: February 2020)

Table of Contents
1. Introduction ·······································································································1(1) Feedless Aquaculture ······················································································1(2) Feed-Supplied Aquaculture ··············································································2
2. Aquaculture········································································································5
3. Seeds ·················································································································6(1) Natural Seeds ································································································6(2) Artificial Seeds ·······························································································6
4. Aquaculture Techniques ·······················································································8
5. Aquaculture Environments ···················································································9(1) Sea Contamination··························································································9(2) Eutrophication and Red Tide ·········································································· 10
6. Observation ······································································································ 10
7. Stormy Weather Precautions ·············································································· 11
8. Fundamental Fishing Knowledge ········································································ 12(1) Fundamentals ······························································································ 12(2) Safety ·········································································································· 13(3) Rope Tying Methods ······················································································ 15

1 . In troduction
Seafood is an e xtr emely importan t foo d source for people. To ensure wecan continue c onsuming seafood in perpetuity, we must take c are of ouroceans and be mindful not to take too mu ch. Howeve r, the glo bal
population has increased and the amount of seafood eaten has gro wn,
leading to a reductio n in fishery resource s. Further , in conjun ction wi th
the abundance resul ting from economic growth, mo re and mor e people
want to ea t delicious seafood, but natural seafood production i s limited.
On the other hand, aquaculture te chnologies have improved . As a result,in addition to "catch ing fisheries" which have been conducted up to now,"aquaculture" has al so come to thrive . Accordingly, new meth ods andaquaculture of fish , shellfish, and seawe ed species that could not be
cultivated be fore are on the rise .
The main aquaculture methods in Japan are as follo ws.
(1) Feedless Aquaculture
This is a method in which aquaculture is conducted without people directly
providing feed, making use of salts, food, and other nutrients in the natural water.
・Hanging Aquaculture (Figs. 1, 2)This is a method of aquaculture in which the organism is cultivated in the water byattaching it to a rope and hanging it, inserting it into a net, or securing it in a similar
fashion. This method of aquaculture is used for mainly species such as Pacific oysters,
scallops, and laver, wakame, and kelp seaweeds.

-1-Figure 1: Pacific oyster aquaculture

Figure 2: Kelp aquaculture(2) Feed-Supplied Aquaculture
This is a method for aquaculture in which sea creatures such as fish or shrimp are
kept in ponds or tanks and given feed to cultivate them.
・Land Aquaculture (Figs. 3, 4)This is a method for aquaculture in which fish are cultivated in manmade pondson land. This method of aquaculture is used mainly for species such as tiger shrimp,
flounder, eel, and trout (such as rainbow trout).

Figure 3: Eel aquaculture

Figure 4: Trout aquaculture

・Netted Tank Aquaculture (Divided Aquaculture) (Fig. 5)This is a method in which fish are cultivated in areas enclosed by nets on thesurface of the water. This method of aquaculture is mainly used for species such as
yellowtail, red sea bream, blowfish, striped horse mackerel, tuna, and carp.

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Figure 5: Tuna aquaculture

As shown in Fig. 6 , the total fishing yield was highest in 1984 , a t abou t
12.8 million tons, an d falling to abou t on e third o f this peak figure, 4.3
million tons, in 2017 . In addition, the aq uaculture yield (201 7) acc ounted
for abou t 1 /4 of the total fishing yield, showing that i t is an i mportant
form of fisheries pro duction.

(10,000 tons)

Figure 6: Japan's total fishing yield (2017)

800
700
600

Inland fishing and aquaculture500

Sea aquaculture

400

Coastal fishing

300

Offshore fishing200

Deep-sea fishing100
01975 1980 1984 1985 1990 1995 2000 2005 2010 2017

Source: Based on the FY2018 White Paper
on Fisheries-3-As shown in Fig. 7 b elow, the haul amou nts of the main type s of fish are
an important compo nent of fishing production.
Haul amounts of main types of fish infishing aquaculture (2017)

Other(49,900t)
Yellowtail
types(138,900t)

Red seabream(59,900t)

Haul amounts of main types of shellfish inshellfish aquaculture (2017)
Other (400t)

Oysters(176,000t)

Scallops(174,400t)

Haul amounts of main types of seaweed inseaweed aquaculture (2017)
Other(55,800t)
Wakameseaweed(49,800t)

Laver(284,200t)

F ig ure 7
So ur ce : " Pro d u c tio n S ta t i st ic s f o r F is hi ng a nd A qu ac ul tu re in
20 1 8, " M in i s try o f Ag ricu l ture , Fo re st ry an d Fi she rie s-4-

2. Aquaculture"Aquaculture" refe rs to a method in which a facili ty (b ree ding facility)that can be managed by people is built, s eeds for cultivation are introduced
to the facility, a favorable envir onment is created through the adjustmentof feeding and breed ing conditions, net r eplacement and pond cleaning, themovement of tanks and rafts , and the s election o f the depth for lowe ring
into the water, and the seeds are heal thfully culti vated a nd grown to asellable size.
In accordance with national law, people who c onduct aqu aculture musthave ob tained licens es for rights o f dema rcated fishery (the ri ght to conductaquaculture), and must endeavor to c rea te products that can deliver safe ty
and peace of mind.
Only lic ensed loca tions can be used as cultivation spots . Those who wish
to conduct aquacultu re cannot simply do so wherever they please.
In addition, conducting cultiva tion for a period of days or months, using
the same method as aquaculture to adjust prices, increase the weight o f theorganism, or wait until shellfish poisons have depleted is call ed farming.

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3 . Seeds
Securing seeds is ess ential to conduct aq uaculture.
"Seeds" refe r to young fish and shellfish that can be cultivated a t an
aquaculture facility for organisms. Th ere ar e both natur al seeds andartificial seeds .

(1) Natural seeds: Species that have a charac teristic of gathering in acertain place at a c ertain time period a nd can be caught in a si zable
number are caught and used as aquaculture seeds. Example s include
creatures born in th e sea, ri vers, and la kes, such as scallops, Paci fic
oysters, yellowtail , tuna, eels , and sweetfish. For the collectio n of thesenatural resources, there are specific time periods, me th ods, andlocations used, and p ermission is require d for each type o r r e gion.
(2) Artificial seeds: T hese seeds are create d by applying sperm to e ggs of thesame species inside a n aquarium, tank, o r o ther enclosure. The eggs are
fertilized , and the seeds are gro wn to a size suitable for aq uaculture
cultivation. These a re or ganisms c reate d with te chnology a nd humaneffor t, and this type of seed is used when natural seeds are difficult tocatch or when ar tific ial seeds have advantages such as faster growth orlower production co sts. So me examples of aquatic li fe cultivated as
artificial seeds are s hown below.

・ Saltwa ter fish: Re d sea brea m, flounder, yellowtail, tuna , tiger puffer ,etc.
・ Freshwater fish: Sweetfish , salmon , ca rp, ca tfish, etc.
・ Shrimp and crab s pecies: Tiger shrimp, blue crabs , etc .

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・ Shellfish species: Pacific oys ters, abal one, mo ther-o f-pearl , etc .
・ Seaweed : Laver , wakame, kelp, etc .
・ Other : Sea ur chin, sea cucumbe r, etc .
*Natural seeds are used for yellowtail and tuna aquacultur e, but theusage of arti ficial se eds has also increase d recently.
Seeds spawned in aquariums from parent fish or shellfish that live in thewater and seeds s pawned in na tural waters are usedas seeds foraquaculture. For thi s reason, i t is important to prote ct fish and shellfish
that lay e ggs in the water so that they r emain abundant. It i s particularly
important to be care ful to not overfish. This is called "managing resources."
By continuing such management, we can stably procure robust seeds long
into the future .
When fish and shell fish are newl y spawned eggs , fr y, or sp at, most a reeaten or die due to l ack of food . As they grow, fish gain improved swimming
ability, shellfish develop tougher shells, and the propor tion o f deaths
decreases.
However , no ma tter how bi g they grow, s ea c reatures will die if the wa ter
quality suffers . Thu s, in addition to the management of fishing resources ,improvement of water quality is also essential fo r stable operation o faquaculture.

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4 . Aquaculture Techniques
Newly spawned fish and shellfish are extremely small and we ak, and havevery li ttle ability es cape from predators, eat, and digest food . Accordingly,
seeds are cultivated in the early stages b y adding seawater fil tered througha land-based aquarium to adjust the te mperature and an a mple supply of
easily-digestible feed with portions sized a ppropriately for thei r gro wth . The
facilities

necessar y

fo r

these

opera tions

differfromth oseused

fo r

aquaculture, so early-stage culti vation is conducted by a fishery cooperativewith a specialized te chnician, seed producer, or similar specia list.
In aquaculture , the seed is procured, c ared fo r, and gro wn . The mostimportant elements in such care are ensuring that oxygen-rich, sanitary
seawater and nutrie nt-rich feed are thor oughly dispersed and that healthy
growth is a chieved without the incidence of disease until shipment. In o rder
to a chieve this, care must be taken to ens ure tha t seeds do not suffer illness
by keeping them fro m bec oming too dens ely packed , providing high -quality
feed in the necessary amounts and at appropriate inter vals, and maintaining
a fa vorable environ ment through changi ng tank ne ts and/or ponds. At first,
the seed are small, so many hatchlings are intr oduced to the culti vating
facility (the cage, a quarium, or tank ). However , in order to grow fish o rshellfish, it is also i mportant to conduct management to gra dually reduce
the numbers kept in the culti vating fa cility (the ca ge , aquariu m, or tank ) as
the fish or shellfish grow. In addition, it is also important to ensure no
attached matter is i ntroduced when adding seawate r so that it’s fr eshness
can be main tained.
In aquaculture, c onsidering the number of seeds firs t in troduced to thecultivating fa cility (the cage, aquarium, o r tank) as 100%, pro duction plansto achieve o ver 80 % of this quantity unlo aded 2 to 3 years la ter.

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5 . Aquaculture Environmen ts(1) Sea Contaminati on
The seas (or rivers) must always be kept in a clean sta te, but the amountof nutrient salt and harmful substances that flo ws in from h ouses, plants,
and fields where humans live on land is extremel y high , and this is said tobe the cause o f the majority of sea conta mination.
In aquaculture , this contamination c an cause fish or sh ellfish being
cultivated to suffer illnesses or die. M oreover , culti vators must also be
careful to a void rais ing seeds in con taminated environments because thiscan negatively a ffe ct the health o f consumers (people).

[Types of Contamination]
・ Contamination fro m land:
Detergents tha t flo w infrom places

where people live , sewage(contaminated water ) and fac tory wastewater, fer tilizers and livestock
feces and urine that flow in from fields a nd ranches, and leftover feedand excremen t (urin e and feces ) fro m places where fish and shellfish
are cultiva ted
・ Contamination res ulting fro m waste th rown into seas o r ri vers
・ Contamination res ulting from oil (there is a great deal of da mage fro m
oil that leaks from s hip accidents)
・ Chemical substances: contamina tion re sulting from chemica ls such asdioxin, mercury, and cadmium (there have been cases o f huma ns being
harmed in the past, so it is necessary to take precau tions aga inst suchcontaminants)
・ Contamination re sulting from the fl ow of mud and/or sand fromdevelopment in loca tions such as mountai ns and along the coa sts-9-

(2) Eutrophication and Red Tide
Eutrophication re fers to an e xcessive increase in mine rals such as
nitrogen (N), phosphorus (P), and silico n (Si) which bec ome nutrients for
phytoplankton. This is caused by from sources such as factories andhouseholds disposing o f wate r which contains an abunda nce of theseelements.
Red tide refers to a state in which c ertain types of phytopla nkton become
excessive due to eu tr ophication, causing the color o f the water to change to
red or b rown.
Eutrophication and red tide cause oxygen in the wa ter to decrease andphytoplankton to bec ome stuck in the gill s of fish , killing them. As a result,these conditions exe rt a major impact on fishing and aquacul ture.

6 . Obser vation
There water at the coast is alwa ys in motion due to the oc eanic currents
and the rise and fal l of the tide. Due to this flow, water is exchanged at
aquaculture locatio ns so that hatchlings can sufficientl y breathe, andvarious types of phytoplankton enter thes e facilities. Howe ver , the seawate r
can become contami nated due to har mfu l substances from la nd, and i f theexchange o f water is insufficient, there is a nega tive impact on gro wth andmaturation.

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At aquaculture l ocations, water fo r cultivation is dra wn, the wa tertemperature , salinity, and oxygen conten t are tested, and obs ervations arecarried out to veri fy whether there is an unpleasant odor or the color o f thewater has changed. I n particular, a t time s when a typhoon ha s passed by ora large amount of ra in has fallen, e tc ., the salinity ma y be l ow (the water
may be s weet) over a large ran ge or wa ter may be clouded b y soil, so it isnecessary to be cauti ous.

7 . Sto rmy Wea ther Pre cautions
When strong winds or hi gh waves oc cur due to lar ge low pres sure syste ms
or typhoons, aquacul ture facilities may b e destroyed . I t is important to pay
close atten tion to we ather fo recasts , look into the strength of strong winds
and high wa ves and the direction of low pr essure systems and typhoons thatare approaching, an d endeavor to mini mize the damage to aquaculture
facilities. When ther e is a possibility of a typhoon approaching, ra fts must
be moved inside the bay and preparations such as increasing mooring ropes
and inspecting the facilities are require d.
In addition, tsuna mis are one exa mple of a frigh tening di saster. Japan
has the highest inci dence of earthquake s in the world, and p eople who live
close to the sea must be a ware that a tsu nami could occur as a result of anearthquake and take precautions acc ordingly.
If you are close to the epicenter of an earthquake, you sho uld assume atsunamis will occur immediately. On the coast of Okushi ri Island in
Hokkaido and the co astal areas o f Iwa te Prefecture and Miyagi Prefec ture,tsunamis occurred within 10 minutes of nearb y ea rthquakes, and many
people were killed. Moreover , there is a risk even for earth quake tha t did- 11 -

not occur in Japan. When the Valdivia earthquake o ccur red in SouthAmerica, a tsunami reached the Japanese coast after so me time andsuddenly increased in height, causing massive damage to ships andculturing ra fts.
When a tsunami co mes, there are extre mely lon g intervals b etween wa ves,
and particularly due to the energy of wa ves in shallow wa te rs, the oceanlevel suddenly rises, potentially engulfing people, ships, and b uildings. The
strength with which a tsunami strikes the coast is e xtremely high, so muchso that e ven if the water le vel is only up to a person's kn ees, it is still
impossible to mo ve.
When a tsunami comes, a tsunami warning is issued by simultaneous
broadcast throughou t the town or city. If you feel an ear thquake, it isimportant to assume tha t a tsunami wi ll strike immediately and make aplan to eva cuate to a n elevated area far a way from the coast.

8 . Fundamental Fishing Kno wledge(1) Fundamentals
・ Pay attention to your health on a daily basis in order to wo rk safel y.
・ In the event of an illness or injury, be certain to r eport i t to the captain.
・ Give yourself extr a time so that you a r e not late to board the ship.
・ On the ship, a void feuding with o ther c rew members and di sturb theorder.
・ The unnecessary u se of open flames is prohibited. Also be c autious ofsmoking.
・ When on the ship, refrain from walking around with your ha nds in yourpockets.

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・ After using tools for various operation s on the ship, quickl y put themaway.
・ When the ship is moving, be care ful n ot to sti ck your hand s or feetoutside of it.
・ Be careful not to o bstruct the view of the people steering th e ship.

(2) Sa fety
○ Clothing (Fig. 8)・ When wor king on the wate r (on deck ), b e sure to wear a wor k-use life
jacket. Life ja ckets a re required when ab oard a ship.
・ Wear a hard hat (helmet) to protec t you r head.
・ When performing dangerous work , use a sa fety belt and a l ifeline.
・ Wear proper clothi ng to avoid getting c aught in mo ving mac hinery andropes.
・ When handling wi res, ropes, and simil ar mate rials, wear s afety glo ves.

Safe

Wear a helmet

Securely fasten yourchinstrap

Wear a work-use life jacket

Safety gloves
Securely fasten the buttons on
your clothes (such as the sleevesand collars)
Wear shoes with non-slip soles(such as boots)

Fig. 8: Safe clothing for work operations- 13 -

○Precautions when o n the water・ Before commencin g work , ensure you h ave a grasp of the wo rk details andsufficient time to co mplete the operation s.
・ When the work are a is conta minated wi th oil o r fish blood, c lean it.
・ If you witness someone fall into the sea , no tify those around you in aloud voice and cas t s omething that floats , such as a life preser ver (lifebuoy), into the sea. Do not attempt to sa ve the person b y yourself.
Float

・ Be careful not to a pproach moving ma c hinery.
・ Be careful not to c arelessly approach r opes or wires being used. Be
careful that your le gs do not ge t tangled in wrapped ropes.
・ When you arrive a t a wor k loca tion, co nfirm the loca tions o f steps andwhere ropes are arra nged.
・ Be especially care ful when it is dark , when you are ge tting on and off
the ship, and when you are moving to ano ther ship. Also be ca reful whencrossing planks.
・ When hoisting a h eavy ob ject using a c rane, confirm that there are nopeople under the loa d. Never carelessly a pproach the area under a crane ,even when it is not moving. In addition, a special license is necessary tooperate a crane .

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(3) Rope Tying Meth ods
・ Sheet bend kno t, double sheet ben d knot: Also re ferr ed to as an
Englishman's knot. This knot is used wh en tying the ends of two ropes ofthe same thickness. The knot does no t ea sily come undone, a nd it is also
used when sewing nets. When tying r opes with diffe rent thicknesses orropes that tend to sli p, a double sheet b e nd is used.

(1)

(2)

(1)

(2)

(3)

(3)

* The upper images show ho w to tie a sheet b end knot, and the lowe r
images show a doubl e sheet bend knot.

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・ Clove hitch : Use d when tying the end of a rope to anothe r object.

(1)

(2)

(4)

(5)

(3)

(1)

(2)

( 3)

(4)

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・ Bowline knot: an important tying method used for applications such as
anchoring. The proc ess differs depending on whe ther the k not is being
draped over an objec t or not.

(1)

(2)

(3)

(1)

(2)

(3)

(1)

(2)

(3)

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(4)

(4)

(4)

・ Anchor bend: this is a safe , dependable kno t used in si tuations such as
when tying a rope to an anchor and lower ing it into the water.

(1)

(2)

(4)

(5)

- 18 -(3)