PRESENT STATUS OF MASS REARING OF FRY AND FINGERLINGS IN THE EIFAC REGION

A.G. Coche and G. Bianchi

Department of Fisheries, FAO, Rome, Italy

ABSTRACT

A survey is given of the information contained in the National Reports on the Mass Rearing of Fry and Fingerlings of Fresh Water Fishes submitted by the EIFAC member countries.

For the 14 most important fish species (or groups of species) the information was grouped into broad subject matters: production purposes, statistics, rearing techniques, production parameters, diseases and parasites, problems and research areas. A geographical distribution of the major species and their culture is given. Some definition on nomenclature are listed.

RESUME

Est récapitulée l'information sur la production en masse d'alevins des poissons d'eau douce, présenté dans les Rapports Nationaux des pays societairs d'EIFAC.

Les données pour les 14 (groupes d') espèces les plus importantes ont été classifiées en groupes par sujet général: buts de production, quantités produites, techniques d'élévage, caractères de production, maladies et parasites, problèmes et recherches. Une distribution géographique des espèces cultivées est tentée. Quelques remarques au sujet de la nomenclature sont faites.

ACKNOWLEDGEMENTS

This general review has been prepared on the basis of National Reports received from the following countries/persons:

The data provided by these reports have been collated by Miss G. Bianchi, in the Inland Water Resources and Aquaculture Service (FIRI) of the Fishery Resources and Environment Division, Fisheries Department, FAO.

1. INTRODUCTION

On the basis of the information provided in the available National Reports, fish species (or groups of species) have been selected to be reviewed in more detail (Table 1). Some other species for which too little information has been provided, are only mentioned as possible important fishes in some European countries.

For each of the selected fish species, the information has been classified into broad subject matters, grouping as far as possible the data on production purposes, statistics, rearing techniques (incl. food/feeds), production parameters (mortality, growth, production), diseases and parasites, specific problems, and future research areas.

To facilitate future discussions on particular data, the name of the country responsible for each piece of information has been closely associated with it (see Abbreviations - Table 2).

In Annex, the geographical distribution of the major fish species and their culture has been attempted, on the basis of available information.

During the preparation of this review, it has clearly appeared that there is a need for better defining the terms “fry” and “fingerlings”. Some of the published definitions have been grouped hereunder, which might be useful as a starting point.

Within the context of this particular review, the following terminology has been used:

1. larvae: from hatching until the first feeding.
2. fry: from the first feeding to 2–3 cm long/up to max. one summer old.
3. fingerlings: from 2–3 cm to 6–15 cm long/generally up to one year old (rarely up to two years).

On some occasions the fingerlings have been subdivided into:

1. young fingerlings: less than one summer old fingerlings.
2. summerlings (estivaux): one summer old fingerlings.
3. yearlings: one year old fingerlings.
4. smolts (salmonids): fingerlings (parr) physiologically adapted to increased water salinity.

Some examples of the published definitions for larvae, alevins, fry and fingerlings:

1. Definitions for larvae

   1. EIFAC Occ. Paper 12, 1978 (Glossary)

      1. Immature stage between egg and adult form: the young of a fish which differs markedly from the adult.

      2. Immature stage between egg and full development of spines and rays in all fins and ossifications of vertebrae.

   2. A. Wheeler, 1978 (key to fishes of Northern Europe)
      Young fish after hatching but still nourished by the egg yolk.

   3. Dr. Horvath, Hungary (pers. comm., 1978)
      From hatching until start of exogenous feeding.

2. Definitions for alevins

   1. EIFAC Occ. Paper 12, 1978

      1. Newly hatched salmon or related fish (usually), with a yolk sac attached, before swimming freely.
      2. Newly hatched, incompletely developed fishes (usually salmonids) inactive on bottom, living off stored yolk.

      3. Stage from hatching to end of dependence on yolk sac as primary source of nutrition (usually salmonids).

   2. Leitritz-Trout and Salmon Culture
      Young fish, especially a newly hatched salmon or trout before absorption of yolk sac.

3. Definitions for fry

   1. EIFAC Occ. Paper 12, 1978

      1. Young stage of fishes, particularly after yolk sac absorption

      2. Young fish, newly hatched, after yolk has been used up and active feeding commenced.

   2. Dr. Horvath, Hungary (Pers. comm., 1978)
      From start of exogenous feeding to formation of final feeding.

   3. Dr. N. Fijan, Yugoslavia (pers. comm., 1978)

      1. “Americans often use the term “fry” for larvae (after hatching)”.

      2. “Others use this term for the period that starts when all larval structures are replaced by definite (adult) ones and ends when fish reach the length of about 50 mm.”

   4. Advanced fry-EIFAC Occ. Paper 12, 1978

      1. Especially from the time the yolk sac is absorbed.

      2. For salmon and migratory trout, see “parr”.

4. Definitions for fingerlings

   1. EIFAC Occ. Paper 12, 1978
      Any fish from advanced fry to the age of one year from the date of hatching regardless of size.

   2. Pennak-Collegiate dictionary of zoology
      Length designation for immature fish from 2.5 cm long (or disappearance of yolk sac) to whatever size is attained at the end of the first year's growth.

   3. Dr. Horvath, Hungary (pers. comm., 1978)
      From formation of final feeding to first autumn (1-summer age).

   4. Allan and Ritter-Salmonid terminology (S. salar)
      The term “fingerling” has been deleted and replaced by “parr” (up to “smolt”);

2. CYPRINUS CARPIO LINNAEUS

2.1 Purpose of juvenile production

1. Further cultivation for food fish production

2. Stocking inland waters (sport and commercial fishery)

2.2 Annual production statistics

PL (1978) larvae 300 m; adv. fry 150 m; fingerlings 1 500 tons

D   (1971) fingerlings 11.6 m

NL (1978) eggs/fry 986 000; fingerlings 81 000

NL (1979) eggs/fry 810 000; fingerlings 120 000

SF (1967–1977) summerlings/yearlings 56 000 (Porla Fish Farm)

2.3 Techniques: water flow, stocking, rate, duration

2.3.1 Pond with water recirculation and biological filters (GB)

2.3.2 Fry production in aquaria and troughs (NL)

1. Aquaria: 4–7 L/min water flow; 25 000 larvae/80 L

2. Troughs for 0.5 g fry production: 6–20 L/min; 10 000 larvae/3 000 L

3. troughs 1.5 g fry production: 10–20 L/min; 5 000 larvae/ 3 000 L

2.3.3 Fry production in ponds (2-phase technique)

1. PL: up to 500 000 larvae/ha for 4 weeks

2. B : 50 000 – 200 000 larvae/ha for 6 weeks

3. H : 100 – 500 larvae/m² for 1 month in small protected ponds (t 20° C)

2.3.4 Fingerling production in ponds (2-phase technique)

1. NL: 100 000 fry/ha for 5–6 weeks

2. B  : 5 000 – 20 000 fry/ha up to summerlings

3. H  : 50 000 – 100 000 fry/ha for 3–4 months in protected ponds
   (2–30 ha; 20–25°C); generally in polyculture with herbivoröus species and sometimes with wels and tench

2.3.5 Fingerling production in ponds (1-phase technique) (SF)

- Brood fish in small ponds (0.1–0.7 ha) in spring

- Spawning: larvae - fry - fingerlings for 4–5 months

- Summerlings harvested in fall and placed in hatchery troughs with spring-water supply (ab. 6.3° C) for winter

- Next spring, yearlings either stocked in natural waters or replaced in rearing ponds for a second summer

2.4 Techniques: natural food and feeds

2.4.1 (GB) - 4–10 days, Artemia salina (100% body weight/day)

- 11–24 days, salmon starter feed (20% BW/day)

- up to 20 g, salmon starter feed (10% BW/day); Qn about 1.5

2.4.2 Fry production in aquaria and troughs (NL)

- Days 4–9 (0.025 g), A. salina 80–125 μm zooplankton (8–12 h/day)

- Days 10–13 (0.060 g), 125–175 μm zooplankton (8–12 h/day)

- Days 13–40 (1.5 g), Trouvit pellets/zooplankton (continuous 12 h/day)

2.4.3 Fry production in ponds (H)

Microzooplankton-rich ponds plus artificial feed (1–2 times/day; 1 kg per 100 000 larvae; Qn = 5–10)

2.4.4 Fingerling production in ponds (H)

Mesozooplankton-rich ponds plus feeding (ground cereals for extensive or pellets for intensive culture; 1/day; 2–5% body weight; Qn = 3–5)

2.4.5 Fingerling production in ponds/troughs (SF)

1. In ponds (spring autumn); natural food and supplementary feeds (ground wheat, ground fish, Lemna minor and Spirodela polyrrhiza, trout pellets)

2. In hatchery troughs (winter): small amounts trout pellets (2/week)

2.5 Production parameters

2.5.1 Mortality rates

1. GB - Very low in recirculation systems except when cannibalism occurs due to discontinuous food supply

2. Fry production in aquaria/troughs (NL): about 25%

3. Fry production in ponds (2 phases): B 30–50%; H 40–60%

4. Fingerling production in ponds (2 phases): B 10–40%; NL 60%; H 30–50%

5. Fingerling production (SF-1 phase): hatchery troughs (winter) summerlings ab. 20%; second winter max. 10%; ponds for yearlings 0–90%

2.5.2 Growth rates

1. NL: 1.5 g fry in 40 days

2. H : 1–2 g fry in 30 days

2.6 Diseases and parasites: prophylaxis and therapy

2.6.1 Recirculation system (GB)

- The brood fishes are treated before entering the ponds with Dipterex and malachite green

- An ultra-violet light sterilizer is incorporated in the system

2.6.2 Fry production ponds (H)

- Ectoparasites on 3–4 weeks old fry, in pond: copper oxychloride (4 mg/L)

- Harvested fry: routine flush-treatment 2–3% salt solutions for a few minutes

2.6.3 Fingerling production ponds (H)

- Control of ciliates (copper oxychloride), gill-worms (insecticides)

- Treatment of gill-necrosis (lime) and swimbladder disease (antibiotics)

2.6.4 Treatment of fingerlings (NL): routine (R), occasional (O), prophylactic (P) or therapeutic (T) treatments

2.7 Specific problems

2.7.1 Recirculation systems (GB): pump failure (duplicate pumps)

2.7.2 Fry production in aquaria and troughs (NL): malformations (unknown cause) and Furanace-resistant Myxobacteria

2.7.3 Fry production ponds (H): water warming up, water filtering, harvesting (traps), predators (frogs), feeds

2.7.4 Fingerling production ponds (H): optimum pond size (3–10 ha), feeds, feeding, harvesting, prevention against diseases (gill-necrosis in particular)

2.7.5 Fingerling production ponds/troughs (SF): water temperature too low for fry growth. Suggests use of heated water

2.7.6 General (D): dry larval feed, water temperature dependence, predation by herons. Suggest warmwater circuits with constant water temperature

2.8 Future research suggestions

2.8.1 Equipment/techniques: (GB) Water aeration, biological filters, mechanical filtretion; (H) harvesting, water filtering, water heating, feeding; (D, SF) controlled fry rearing in heated water

2.8.2 Nutrition/feed technology: (H) nutrition biology: (B, D, SF) complete dry feed for young fry (and fingerlings)

2.8.3 Diseases: (NL) Myxobacteria taxonomy and immunology; (D) gill-necrosis; viral vaccination; (H) fingerling pond sanitation

2.8.4 Production techniques: mono/polyculture of fingerlings in larger ponds; fingerling wintering

3. TINCA TINCA (Linnaeus)

3.1 Purpose of juvenile production

1. Further cultivation (gen. as an accompanying species for carp)

2. Stocking inland waters (sport fishing)

3.2 Annual production statistics

PL (1978): fingerlings 15 tons

SF (1967–77): summerlings/yearlings 52 000 (Porla Fish Farm only)

D (1971): fingerlings ab. 3 millions

CH (1977): summerlings 2000; yearlings 7889 (partim)

3.3 Techniques for production of juveniles

Natural propagation occurs in ponds. Generally tench is reared together with common carp, using a similar technique. Slight differences however exist:

1. Rearing of fingerlings (H): being a competitor for carp, tench fingerlings are preferably stocked with chinese carps (larger ponds; water warmer than 20–24° C; 10 000 to 50 000 one-month fry/ha for 3–4 months; survival 20–30%)

2. SF: tench summerlings can already overwinter in the ponds during the first winter. By the end of the second summer, survival is about 70%.

3.4 Techniques: natural food and feeds

- In general, only natural food is made available (B, D, SF)

- Some special care is sometimes given (H):

1. In fry ponds, smaller plankton is required by larvae

2. In fingerling ponds, preference for those with a deep organic sediment layer

3.5 Diseases and parasites

1. Local control of Ergasilus (D)

2. Treatments for Trichodina (H) with copper oxychloride

3.6 Specific problems/research suggestions

1. Food competition in polyculture (H)

2. Sometimes high mortality of 1–2 cm fingerlings for unknown reason (D)

3. Artificial propagation/hatchery rearing techniques (B, D)

4. CHINESE CARPS

1. Ctenopharyngodon idella (Val.): grass carps

2. Hypophtalmichthys molitrix (Val.): silver carp

3. Aristichthys nobilis (Rich.): big head

4.1 Purposes of juvenile production

1. Further cultivation in ponds, generally in polyculture with common carp (H, PL). Use of C. idella only in NL.

2. Stocking inland waters:

   - For specific purposes (D): reduction of higher plants/algae using C. idella; reduction of phytoplankton and yield increase using H. molitrix; and reduction of zooplankton using A. nobilis.

   - For closed waters only (H), H. molitrix and A. Nobilis being not stocked for sport fishing.

4.2 Annual production statistics

PL (1978) larvae 70 m; fingerling 15 tons

NL (C. idella - 1978) eggs/fry 120 000 +; fingerlings 105 000

NL (C. idella - 1979) eggs/fry 80 000; fingerlings 70 000

4.3 Techniques: water flow, stocking rate, duration

4.3.1 Fry production in aquaria and troughs (C. idella in NL): Similar to common carp fry production - see 2.3.2

4.3.2 Fry and fingerlings production in ponds (H)

- Similar to common carp - see 2.3.3 and 2.3.4, but optimal water temperatures are 2–4° C higher.

- Favoured ratio of species for polyculture: C. carpio 60–70%; H. molitrix and A. nobilis 20–30%; and C. idella 1–10%.

4.4 Techniques: natural food and feeds

4.4.1 Fry production in aquaria and troughs (NL)

- Days 5–10 (0.03 g), A. salina /80–125 μm zooplankton (8–12 h/day)

- Days 10–16 (0.14 g), 125–175 μm zooplankton (8–12 h/day)

- Days 16–36 (1.5 g), Trouvit pellets/zooplankton (continuous 12 h/day)

4.4.2 Fry production in ponds (H)

- Similar to common carp (see 2.4.3) but a higher percentage of soya meal is used

4.4.3 Fingerling production in ponds (H)

- Similar to common carp (see 2.4.4) but less cereals and more alfa-alfa meal/soya meal are used. Pellets contain more plant materials.

4.5 Production parameters

4.5.1 Mortality rates

4.5.2 Growth rates

1. NL: 1.5 g fry produced in 36 days after hatching

4.6 Diseases: prophylaxis and therapy

4.6.1 Fry and fingerling production ponds (H)

- Similar to common carp (see 2.6.2 and 2.6.3)

- Juveniles are less prone to diseases than carp

4.6.2 Treatments of fingerlings (NL): similar to common carp (see 2.6.4)

4.7 Specific problems

4.7.1 Fry production in aquaria and troughs (NL): malformations (unknown cause) and Furanace-resistant Myxobacteria

4.7.2 Fry production ponds (H): control of water temperature for optimum production; supplementary feeds.

4.7.3 Fingerling production ponds (H): optimal ratio of species in polyculture.

4.7.4 General (D): import and spreading of parasitosis

4.8 Future research suggestions

1. Controlled rearing of fry (D)

2. Nutrition biology (H); larval feed for young fry (D)

3. Water temperature control in fry ponds (H)

4. Ratio of species in polyculture (H)

5. Taxonomy and immunology of Myxobacteria (NL)

5. SCARDINIUS ERYTHTROPHTHALMUS (Linnaeus)

5.1 Purpose of juvenile production

NL: Stocking of catchable rudd in inland waters (sport fishing)

5.2 Production of fingerlings in ponds (NL)

1. Broodstock in 0.2–3 ha ponds in spring (ab. 20 kg/ha)

2. Natural spawning from late May to mid-July

3. If pond fertilization is used, polyculture with common carp and grass carp (100–200 two-year-old/ha) for algae control.

4. Harvest in next spring (April) or after two growing seasons.

5. Av. yield of yearlings: 40 000/ha (0.6–6.5 g) Av. yield of 2-year-old fingerlings: 12 000/ha (4.8–34.5 g)

5.3 Feeding: experimental use of pellets (Qn 8)

5.4 Diseases: fungal gill infection succesfully controlled with copper sulfate (5 kg/ha)

5.5 Problems: slow growth; low production; size heterogeneity

5.6 Research

1. Hatchery production of fry

2. Hatchery production of fingerlings

6. RUTILUS RUTILUS (Linnaeus)

6.1 Purpose: stocking of inland waters for sport fishery (PL, GB)

6.2 Statistics: PL 12 tons/year (1978)

6.3 Fry production in indoor hatchery (GB)

1. Water supply: aerated, heated river water (R. Trent; power stations)

2. Induced spawning

3. Feeds: A. salina/natural food from river

4. Growth: to 20 mm in about 30 days

6.4 Fingerling production in ponds (GB)

1. Stocking: fry (20 mm)

2. Feeds: natural food/pellets (30% protein)

3. Growth: 8–9 cm in first growing season
   15 cm in two years (stockable size)

4. Survival: 90–100%

6.5 Diseases/Parasites (GB): white spot disease and Costia may cause problems in heated water (formalin treatment)

6.6 Specific problems: (GB): development of maturity for induced spawning

6.7 Research (GB): polyculture with carp; planktonic population dynamics; supplementary feeds

7. SILURUS GLANIS Linnaeus

7.1 Purpose

1. Stocking natural waters (D, H)

2. Further cultivation in polyculture as food fish (H)

7.2 Fry production in hatchery troughs (H)

1. Stocking rate: 5 000–10 000 larvae/100 L for 1 month

2. Water temperature above 20° C

3. Feeds: cut Tubifex ad lib., every 3–4 h

4. Mortality: 10–70%

7.3 Fry production in nursery ponds (H)

1. Stocking rate: 1–2 larvae/m² for 1 month

2. Water temperature above 20° C

3. Natural food and supplementary feeds (high animal protein content; 1–2 kg/ 10 000 fry; Qn 5–15)

4. Mortality: 10–70%

7.4 Fingerling production in ponds (H)

1. Stocking rate: 500–5 000 fry/ha for 3–4 months

2. Pond size: 2–30 ha each

3. Polyculture with common carp and Chinese carps

4. Food: forage fish

5. Mortality: 30–50%

Experiments are in progress on pond monoculture and recirculation systems, feeding pellets.

7.5 Diseases/parasites (H)

1. Parasites: malachite geen, salt, copper oxychloride

2. Bacterial diseases: antibiotics

7.6 Major problems

1. Starter feed for fry; feed for fingerlings (H)

2. Fry rearing technology in hatchery (D)

3. Diseases of fry and fingerlings (H)

4. Monoculture technology

7.7 Future research

1. Fry rearing technology (D)

2. Feed technology (H)

3. Disease prophylaxis (H)

8. LUCIOPERA LUCIOPERA (Linnaeus)

8.1 Purpose of juvenile production

1. Stocking natural waters, generally with summerlings

2. Further cultivation in ponds, as auxilliary species (D, H)

8.2 Annual production statistics

D (1977) - Niedersachsen: 60 000 fingerlings (6–8 cm)

SF (1977): eggs/fry several millions; summerlings ab. 130 000

PL (1978): fry 0.2 million fingerlings 34 tons

8.3 Techniques: ponds, stocking rate, duration

8.3.1 One-phase technique in ponds

NL: in carp fattening ponds, a few couples of brood fish are stocked in late April to produce summerlings

H: in large carp ponds, stocking of brood fish with nests for 4–5 months

8.3.2 Two-phase technique: fry production in ponds

1. NL: ponds ab. 1.5 ha; waterfilling just before stocking; stocking 2 couples broodfish on last day of April; harvest in July. Herbicide treatment (Diuron) to prevent growth of filamentous algae.

   Rem.: method only used if one-phase technique could not be applied

2. H: medium size-ponds; water temperature 10–16° C; stocking 1–2 m/ha ripe eggs or 50 000–80 000/ha feeding larvae, for one month.

8.3.3 Two-phase technique: fingerling production in ponds

1. NL: carp fattening ponds: from July to end summer

2. H: carp ponds; 200–300 fry (40 mm) per ha for 3–4 months

8.4 Techniques: natural food only

8.4.1 Fry ponds: essential need for zooplankton

(a) NL: filling of the ponds just before stocking the brood fish

(b) H: well prepared ponds (abundant plankton) and fertilization

8.4.2 Fingerling ponds: fertilization

Rem.: In Belgium, rudd and roach are stocked as forage fish.

8.5 Production parameters

8.5.1 Mortality rates

1. 50% during the first year of life (D)

2. Fry ponds 80–95%; fingerling ponds 80–90% (H)

8.5.2 Growth rates

1. NL: 1 g fry in ab. 3 months (late April–July)

2. H: 40 mm fry in one month

8.5.3 Production rates

1. NL in fry ponds: 10 000–100 000/ha (avg. 30 000/ha)

8.6 Diseases and parasites

- No prophylaxis of diseases (H, SF)

- Parasitic infection (Trichophrya) once observed (NL)

8.7 Specific problems

8.7.1 Shortage of brood fish (SF): construction of broodfish farms and fisheries regulations

8.7.2 Feeding: - natural food in adequate size and abundance (H, NL)

- artificial feeds lacking (SF)

8.7.3 Production technique: not yet very succesful (NL) the 2-phase giving no better results than the 1-phase technique

8.7.4 Mortalities

- high sensitivity to injuries (H)

- cannibalism (H)

- summer-deaths (D)

8.8 Future research suggestions

8.8.1 Broodfish farming techniques (SF)

8.8.2 Fry rearing techniques (D)

8.8.3 Natural food populations - H - (zooplankton regulation - NL)

8.8.4 Artificial feeds for fry and fingerlings (SF)

9. ESOX LUCIUS Linnaeus

9.1 Purpose of juvenile production

1. Stocking of natural waters for sport/commercial fishery (B, D, H, NL, PL, SF)

2. Further cultivation as a predator (B, D)

9.2 Annual production statistics

1. D - Niedersachsen (1977): fry 2.5 m; fingerlings (5–6 cm) 0.3 m

2. CH (1977 partim): fry 25.55 m; fingerlings 115 200; summerlings 805 740; yearlings 17 200

3. NL (1978): fry 3.046 m; fingerlings 1.278 m
   NL (1979): fry 3.274 m; fingerlings 1.3 m

4. PL (1978): hatched larvae 10 m; fingerlings 23 tons

5. SF young fry 44 m; 5–7 cm fry 0.6 m

9.3 Techniques: waterflow, stocking rate, duration

9.3.1 Fry production in Californian troughs (NL)

Water flow 6 L/min; 60 000 larvae/6 trays/trough

9.3.2 Fry production in tanks (H)

Water temp. 10–14°C; 8 000–10 000 larvae/100 L for 2–3 weeks

9.3.3 Fry production in small ponds (H)

Small ponds; water temp. 10–14° C; 100 larvae/m² for 1 month

9.3.4 Fry production in larger ponds

1. 10 000–25 000/ha for 6 weeks (B)

2. in 5–8 weeks (SF)

9.3.5 Fingerling production in rectangular troughs (NL)

Water flow 7–27 L/min; 20 000 fry/3 000 L for 1 month

9.4 Techniques: natural food and feeds

9.4.1 In troughs (NL): from 8 to 30 days after hatching (upto 0.45 g), zooplankton 3 times/day

9.4.2 In tanks (H): zooplankton and cut Tubifex

9.4.3 In ponds (H, SF): natural food (larger zooplankters)

9.5 Production parameters

9.5.1 Mortality rates

1. Fry production in troughs (NL) 12%

2. Fry production in tanks (H) 80–90%

3. Fry production in small ponds (H) 20–30%

4. Fry production in larger ponds (B) 50–95% (avg. 80%)

5. Fingerling production in troughs (NL) 33%

6. Total losses during rearing (D) 50–95%

9.5.2 Growth rate

1. 0.45 g during first month (troughs in NL)

2. 5 g (9–10 cm) in 6 weeks (ponds in B)

9.6 Diseases and parasites: prophylaxis and therapy

9.6.1 Eggs in conieal jars (NL): pike fry rhabdovirus disease; wescodyne 3 ‰ for 10 min, immediately after fertilization and 65% development (routine; prophylaxis)

9.6.2 Fry in troughs (NL): Saprolegnia; malachite green 0.1 ppm for 1 h, 2/week (occasional; therapy)

9.6.3 Fry in tanks (H): ectoparasites; salt flush treatment

9.6.4 Fingerlings in troughs (NL)

1. Saprolegnia and Ichthyophthirius; malachite green 0.1 ppm for 1 h, 3/week (routine, prophylaxis, therapy)

2. Myxobacteria; furanace 10 ppm for 1 h, 1/week (occasional; therapy)

9.7 Specific problems

9.7.1 Sudden weather cooling (B): later stocking in spring

9.7.2 Cannibalism: in tanks and troughs especially (NL, D, H) but less pronounced in ponds (H). Related to feeding (particle size and abundance of zooplankters - NL)

9.7.3 Lack of accepted dry feeds (D)

9.7.4 Zooplankton short supply (D)

9.8 Future research suggestions

9.8.1 Fry production techniques in troughs with artificial feeds (B)

9.8.2 Reduction of cannibalism in tanks (D)

9.8.3 Reduction of cannibalism in ponds (SF): feeding, grading; special pond construction

9.8.4 Dry feeds for fry (SF)

9.8.5 Intensification of the rearing technique and increase of the pond productivity (SF)

10. COREGONUS spp

PL C. albula (L.), C. peled (Gmelin), C. lavaretus (L.)

SF C. lavaretus (L.), C. muksun (Pallas), C. peled (Gmelin), C. pidschian (Gmelin)

10.1 Purposes of juvenile production

1. Stocking natural waters (D, DK, PL, SF, CH) including brackish waters (DK. SF)

10.2 Annual production statistics

10.3 Rearing techniques: Stocking and yield

10.3.1 Rearing fry in floating cages in lakes, with electric light to attract zooplankton at night (PL)

10.3.2 Rearing fry in tanks with natural food (D)

10.3.3 Rearing fry in ponds with natural food (SF):
ponds 100 m² – 200 ha drained during winter; liming if necessary (500–1000 kg/ha); stocking newly hatched fry (10 000–30 000/ha) for 100–140 days; harvest in Sept.–Oct. (summerlings): most productive ponds 10 000–15 000/ha (10–15 g) and less productive ponds 2 000–4 000/ha (2–4 g); average mortality 60%

10.3.4 Rearing fingerlings in carp ponds (D)

10.4 Rearing techniques: natural food and feed

10.4.1 Natural food (zooplankton): inorganic fertilization (SF)

10.4.2 Supplementary feeding: fishmeal (smelt-SF), trout pellets (DK, SF), fresh or dried plankton (DK, SF). Such feeding can start at 2 cm length with Qn 5 (D)

10.5 Specific problems

10.5.1 Ponds design/construction (SF): harvesting, wild fish

10.5.2 Feeding the fry with zooplankton when scarce: delay spawning/hatching; use A. salina; dry feed (D)

10.5.3 Survival after stocking in natural waters (DK)

10.6 Future research suggestions

10.6.1 Fishery regulation for optimum broodfish stock management (D)

10.6.2 Pond construction/engineering (SF)

10.6.3 Harvesting techniques (SF)

10.6.4 Rearing techniques for higher productions: fertilization/dry feeds (SF)

10.6.5 Intensification of techniques: net cages, tanks and ponds (SF)

11. SALMO GAIRDNERI Richardson

11.1 Purposes of juvenile production

11.1.1 Further cultivation to marketable size (mainly)

11.1.2 Stocking natural waters

11.1.3 Export (DK fry; NL fingerlings)

11.2 Annual production statistics

PL (1978): fingerlings 160 tons

CH (1977 partim): fry 528 000 fing. 370 800 summerlings 856 118 yearlings 296 429

D (1971): fry ab. 62 m; fingerlings ab. 27 m

NL - OVB (1979): fry 180 000; fingerlings 160 000

NL - other: ab. 1 m (30% for cultivation/stocking; 70% fingerling export)

NL (1976): fry state 0.246 m; fry industry 4.617 m; summ. state 18 000; fing. industry 6.932 m

11.3 Techniques: water flow, stocking rate, duration

11.3.1 Fry production in California troughs (NL): water flow 6 L/min; 60 000/6 trays; at 14° C

11.3.2 Fry production in indoor concrete tanks (DK)

11.3.3 Fry production in nursery ponds (D)

11.3.4 Fingerling production in circular tanks (NL): at 14°C

1. Production of fingerlings up to 1 g: 10–15 L/min; 10 000/2 400 L

2. Production of fingerlings up to 3 g: 15–20 L/min; 5 000/2 400 L

11.3.5 Fingerling production in ponds (B): 4–6 m²

11.3.6 Fingerling production in raceways (B): 1000/m²

11.4 Techniques: feeding methodology

11.4.1 Troughs and circular tanks - Fry/fingerlings (NL)

1. 4–18 day old: Trouvit pellets/zooplankton; 8–10 h/day

2. 18–28 day old: Trouvit pellets/zooplankton; contin. 12 h/day

11.4.2 Indoor concrete tanks - Fry (DK)

Feeding charts; pellets; automatic feeders usually, 3/hour from 4.00 to 19.00 h; Qn 1–1.3

11.4.3 Circular tanks and concrete ponds - Fingerlings (D)

Pellets (35–40% protein); 1–5% biamass/day; Qn 1–2

11.4.4 Tanks (CY)

1. Fry: pellets; 8–10% biamss/day in 8–10 meals; Qn 1–1.3

2. Fingerlings: pellets; 6–10% biomass/day in 4–6 meals; Qn 1–1.3

11.5 Production parameters

11.5.1 Mortality rates

1. Fry production in Californian troughs (NL): 30%

2. Fingerlings production in circular tanks from fry (NL): 10%

3. Fry production in concrete tanks (DK): 10–90%

4. Fingerling production in tanks from eggs (CY): 25%

5. Summerling production in stations (N): 47%

11.5.2 Growth rates

1. In troughs and tanks (NL): 3 g in about 48 days (14° C)

2. In tanks, at relatively high t (DK): 5 cm in 6 weeks

11.6 Diseases and parasites: prophylaxis and therapy

11.6.1 Fry production in Californian troughs (NL):

1. Eggs (virus): Wescodyne; 3‰ for 10 min. once (occasional, prophyl)

2. Fry (Saprolegnia/Ichthyophthirius): mal. green; 0.1 ppm for 1 h once/day (routine; prophylactic; therapy)

11.6.2 Fingerling production in tanks (NL)

1. Ichthyophthirius: malachite green; 0.1 ppm for 1 h; 2/week (R, P, T)

2. Myxobacteria: furanace; 10 ppm for 1 h; 2/week (R, P, T)

3. Costia necatrix: trypaflavin; 20 ppm for 1 h; 1/week (R, P)

11.6.3 Fry production in concrete tanks (DK): use of spore-free water (ground or well) to prevent Myxosoma infection; eradication programme to prevent spread of IPN

11.6.4 General (D): prophylaxis through strict hygienic measures in hatchery and in ponds. Separation into age groups

11.6.5 Pond desinfection (CY): FAM 30; sodium chloride; 40% formalin

11.7 Specific problems

11.7.1 Water supply; (a) flow and temperature (NL)

(b) pollution (D)

11.7.2 Malformations (NL)

11.7.3 Diseases (DK): (a) Virus infections (IPN, VHS, etc)

(b) Control of communicable diseases

(c) Eradication programmes

11.8 Further research suggestions

11.8.1 Genetics: selective breeding for more productive strains(D, CY)

11.8.2 Nutrition/Feeds: fry and fingerlings (CY)

11.8.3 Diseases: (a) Viral vaccination (D, DK)

(b) Disease-resistance through feedstuffs (D)

(c) Disease-controle (DK: farms IPN-free)

12. SALMO TRUTTA TRUTTA Linnaeus and SALMO SALAR Linnaeus

12.1 Purposes of juvenile production

1. Stocking natural waters (D, Dk, PL, S, N)

2. Further cultivation (N)

12.2 Annual production statistics

D (1971): S. trutta fry ab. 11 m; fingerlings ab. 4 m

S (incl. S. salar): 3 million 2-year-old smolts

PL (1978): S. trutta hatched larvae 3 m; advanced fry 0.8 m

N (1976/77): S. trutta fry stage 2.119 m, S. trutta summ. stage 0.202 m

N (1976/77): S. salar fry stage 7.404 m; fry ind. 4.076 m; summ. stage 1.267 m; smolt ind. 1.843

12.3 Techniques: environment, water flow, stocking rate

12.3.1 See S. gairdneri but capture of some wild brood fish (D, DK)

12.3.2 Production in tanks and ponds (S)

1. Environments available 1978: (i) wooden/plastic troughs

   (ii) Intensive rearing: plastic tanks 2 200 m²; concrete tanks 12 000 m; steel tanks 1 200 m²; wooden tanks 100 m²; circular ponds 10 500 m²; total area 2.6 ha

   (iii) Extensive rearing natural ponds area ab. 116 ha

2. Intensive rearing water flow: 10–15 L/min/m²; rotating water mass; horizontal bottom; central outlet

3. Stocking rates: in summer up to 4 kg/m² but considerably more in winter

12.4 Techniques: feeding methodology (S)

1. Automatic feeders distribute pellets

2. avg. daily rations per 100 kg biomass: at 2° C, 0.1 kg; at 10°C, 0.7–3.1 kg; at 18° C, 1.2–7.5 kg; according to water quality and fish size

12.5 Production parameters (intensive techniques - S)

1. Total expected mortality from eggs to smolt averages 40%

2. Partial mortality expected as follows:

12.6 Diseases and parasites: prophylaxis and therapy (S)

12.6.1 Prophylaxis:

1. Organized health control at all stations since 1961

2. Reduction of stress (crowding, handling, water quality, photoperiod)

3. Hygienic measures (desinfections, transport regulations) and stamping-out programmes

4. Treatments against skin/gill parasites and bacteria (formalin, malachite geen, nifurpirinol)

12.7 Future research suggestions

12.7.1 Genetic diversity in Baltic S. salar stocks (S)

12.7.2 Long-term storage of gametes (S)

12.7.3 Parr/smolt transformation (S)

12.7.4 Quality of smolts produced (S)

12.7.5 Survival of 1-year-old smolts after release (S)

12.7.6 Diseases (a) Influence of environmental stress (S)

(b) Relationship disease/quality of smolts (S)

(c) Relationship broodfish condition/diseases (S)

(d) Practical method for vaccination (D)

12.7.7 Recirculation systems: removal of waste products (N)

12.7.8 Production of 1-year-old smolts in recirculation systems using heated water to reduce production costs (N)

13. SALVELINUS Spp

1. S. alpinus (Linnaeus): artic char

2. S. fontinalis (Mitchill): brook trout

3. S. namaycush (Walbaum): (American) lake trout

13.1 Purposes of juvenile production

1. Export of eyed ova (DK - 3 species)

2. Stocking natural waters (D, N: S. alpinus + S. fontinalis; CH - 3 species)

13.2 Annual production statistics

1. CH (1977 partim):

   - S. alpinus fry	236 000;	fing.	440 966;	summ.	176 797;	yearlings	9 195
   - S. fontinalis-	nil	-	9 700	-	11 550	-	500
   - S. namaycush -	nil	-	9 000	-	195 150	-	22 750

2. D: S. alpinus fing. Bayern ab. 50 000; S. fontinalis fing. Niedersachsen 100 000

3. DK: ab. 1 million ova for each of the 3 species

4. PL: fry 0.2 milliom; fingerlings 1 ton

5. N: (1976/77): S. alpinus fry 159 000

13.3 Production techniques

13.3.1 S. alpinus

D:   controlled hatching(less than 7°C water) and fry rearing; production of fingerlings in ponds with abundant natural foods; capture of broodfish in natural waters; feeding live food/moist feed/dry first ad. lib., then up to 50% biomass daily

DK: controlled hatching (troughs); fry rearing in ponds; broodfish stock; feeding fry with dry pellets and fingerlings with wet feed/binders

13.3.2 S. fontinalis

D:   broodfish captured in natural waters; techniques similar to S. gaidneri

DK: same as S. alpinus (water temperature 5–7° C)

13.3.3 S. namaycush

DK: same as S. alpinus (water temperature 5–7° C)

13.4 Production parameters: mortality

D:   up to 90% (fry S. alpinus); up to 40% (fry S. fontinalis)

DK: average 20% from eggs to 1-year-old

13.5 Specific problems

13.5.1 S. alpinus - fry rearing technique (D)

- feeding of fry dyring first days (D)

- mortality for generic reasons (DK)

13.5.2 S. fontinalis - broodfish stock storage in ponds (D)

- feeding of 2-month-old fry when transfer to ponds (DK)

13.5.3 S. namaycush - feeding of 2-month-old fry when transfer to ponds (DK)

13.6 Future research suggestions

S. alpinus (D) - dry feed for fry

- broodfish stock constitution

14. HUCHO HUCHO Berg

14.1 Purpose of juvenile production

1. Stocking natural waters (D, PL)

14.2 Annual production statistics

PL (1978) fry 50 000

D-Bayern ab. 10 000 fingerlings

14.3 Production techniques (D)

- Fry rearing in natural ponds with sufficient natural food

- Fingerling production in ponds

- Feeding live food (chironomid larvae, zooplankton) and moist feeds (liver, spleen, fish)

- Mortality up to 90%

14.4 Specific problems (D)

- Cannibalism (esp. fry in tanks)

- Feeding

14.5 Research suggestions (D)

- Broodfish storage/feeding

15. THYMALLUS THYMALLUS (Linnaeus)

15.1 Purpose of juvenile production

1. Stocking natural waters (CH, D, PL, N)

15.2 Annual production statistics

PL (1978) hatched larvae 0.4 m; fingerlings 60 000

CH (1977 partim) fry 540 000; fing. 425 300; summ. 379 628; yearl. 3 577

D-Bayern fingerlings 1 m; Niedersachsen (1977) fingerlings 60 000

N (1976/77) fry 207 000

15.3 Production techniques/parameters (D)

- Capture of broodfish in natural waters

- Hatchery troughs (hatching)

- Fry rearing in ponds

- First feeding zooplankton; at 14 days, addition dry feed ad libitum

- Mortality: 50–60% fry; high mortality in tanks with dry feed only

15.4 Specific problems (D)

- Capture broodfish

- Zooplankton supply for feeding

15.5 Research suggestions (D)

- Broodfish storage/feeding

- Dry feed for fry

16. TABLES

TABLE 1. Important fish fo juvenile production in the EIFAC - Region

(* indicates lack of information for this review)

TABLE 2. Abbreviations used in text and in Annex.

TABLE 3. Status and occurrence of cultivated fish species in the EIFAC member countries

Abbraviations: + present in the country;
- absent from the country;
o cultivated - National Report;
(o) experimental - National Report

Annex

- Geographical distribution of major cultivated fish species in the EIFAC Region.