Survival and changes in growth of juvenile tench (Tinca tinca L.) fed defined diets

commonly used to culture non-cyprinid species

By M. Quiros, N. Nicodemus, M. Alonso, M. Bartolome, J. L. Ecija and J. M. R. Alvarino

Departmento de Production Animal, Escuela Tecnica Superior de Ingenieros Agronomos, Universidad Politecnica de Madrid,Ciudad Universitaria, Madrid, Spain

Summary

The study is an attempt to evaluate the feasibility ofintensive tench culture using non-specific diets as a prelim-

inary step to check the acclimatization of the species underintensive rearing systems. Five-month-old juvenile tench werereared in recirculating systems at mean water temperatures

of 22�C for 75 days. Fish fed with four different commercialdiets (trout starter, trout first feeding, sea-bass and eel),showed significantly higher final weights than the fish fed

either eel or sea-bass diets. Initial weight for all treatmentswas 2.3 ± 0.53 g. Final weight for the commercial dietgroups was 3.56 ± 0.4 g, compared with the remaininggroups that reached 2.09 ± 0.47 g (P < 0.05). Significantly

higher survival rates were observed in the eel and sea-bassgroups (84.7 and 51.5%, respectively) than in either of thetrout diet groups (38%). Specific growth rates (1.26 vs –0.18)

and condition factor (1.26 vs 0.93) were also higher thanthose fed with salmonid diets (P < 0.05). Results obtainedin this study indicate that regardless of the species� slow

growth, when compared with other cyprinids, final growthrates and survival of tench fed exclusively on sea-bass or eeldiets can be considered satisfactory. It must be pointed out

that these promising results were obtained at lowertemperatures than previous studies of tench in culturesystems. The use of belt feeders did not show improvementin growth compared with manually fed fish when trout diets

were used.

Introduction

Tench (Tinca tinca L.) is a continental freshwater fish widelydistributed throughout Spain and with a high demand in local

markets. Traditional pond methods for tench production areunsatisfactory, mainly due to high mortalities during theearliest stages and extremely poor growth rates (Steffens,1995). At present, there are no specifically formulated diets for

the different development phases of this species (Quiros, 1997),however, a live food supplement is beneficial under controlledculture conditions (Quiros and Alvarino, 1998). At least in

Spain, tench farming usually uses a variety of commercial dietssuch as those for carps, salmonids, or even for marine fish suchsea-bass or sea-bream.

In the present 75-day study, four commercial dry diets (twofor salmonids, one for sparids and one for eel) were fed tojuvenile tench after an initial feeding of natural food in ponds.

The aim of the trial was to observe if any of the commercialdiets would be suitable for use in the early on-growing periodof controlled tench production. At the same time, survival and

growth rates were also monitored. Additionally, manual vsautomatic feeder growth rates were compared.

Material and methods

Fish, facilities and experimental procedure

Two different trials were conducted to test the feasibility of fourdifferent diets. Juvenile tench from a commercial fish farm inExtremadura (Spain) were transferred to the university facilit-

ies. Fish were held in aerated 200-dm3 tanks in a recirculatingwater system provided with biological and mechanical filtra-tion. Each tank was stocked with 25 fish. The photoperiodregime was set at 16L : 8D. Mean water temperature of

22 ± 2�C was controlled by a heater system. Dissolved oxygensaturation was 70–80%, pH ranged between 8.0 and 8.5 andtotal ammonia and nitrites were below 0.05 mg dm)3.

At the beginning of the study, the 5-month-old fish had totallengths (TLs) and wet body weights (BWs) of 5.95 ± 0.43 cmand 2.3 ± 0.53 g, respectively (mean ± standard deviation;

n ¼ 300). Each morning, uneaten food, faeces and other wastewere siphoned off.Experiment 1 (A1–A4) compared manual vs automatic

feeding of two kinds of trout food (Table 1). Experiment 2compared four diets supplied manually: trout starter and troutfirst age (A3, A4), and eel and sea-bass diets (B1, B2)(Table 1). Both trials were duplicated.

Diets and feeding

Four commercial diets were fed to the fish: (trout starter andtrout first feeding: Nutrisa, SA; eel and sea-bass: Dibaq),analysed to determine dry matter, ash, crude protein and net

fat (AOAC, 1990), and energy content by means of calorimetry(IKA C-400 equipment) (Table 2). Pellets ranged in size from0.5 to 1.2 mm.Diets supplied manually were given five times a day during a

12-h period (08:00–20:00 hours), 5 days a week. Diets suppliedautomatically were given using belt feeders (clockwork driven)capable of releasing food continuously over a 12-h period.

Daily feeding rates were supplied slightly in excess of quantity,approximately 5% of the fish total biomass.

Measurements and data analysis

Every 15 days of the trial, all fish in each tank (25 individuals

per tank) were collected with a fine net and lightly anaesthe-tized using MS 222 (Sandoz). The individual TLs (TL to thenearest 0.1 mm) and wet BWs (BW, to the nearest 0.1 mg)

J. Appl. Ichthyol. 19 (2003), 149–151� 2003 Blackwell Verlag, BerlinISSN 0175–8659

Received: May 30, 2002Accepted: December 20, 2002

U.S. Copyright Clearance Centre Code Statement: 0175–8659/2003/1903–0149$15.00/0 www.blackwell.de/synergy

were determined from measurements taken on five occasionsduring the 75-day experiment. Specific growth rates (SGRs)were expressed as SGR ¼ (le WT ) le Wt)/T; condition factorK ¼ W/L3, WT being the final weight, Wt the initial weight,

T the time of the experiment in days, L the total length and lethe logarithm on e base fish. Temperatures and mortalities(none observed) were registered daily.

Experiment 1 (groups A1–A4) was analysed as a factorialdesign (2 · 2), while the second experiment (B1, B2, A3, A4)was analysed as a randomized one-way ANOVAANOVA with the diet

type as the main source of variation. Differences in mortalityrates were analysed with a non-parametric procedure, Categ-orical Data Modeling (CATMOD) (SAS/STAT, 1987).

Results

Experiments showed a clear convenience of feeding juvenile

tench, whether eel or sea-bass diets, when compared withsalmonid food (P < 0.05), showing 5.8, 48.3, 24.4 and 423%increases in length, weight, K and SGR, respectively (eel and

sea-bass combined).Our results showed that manual feeding of juvenile tench

given either the eel (B1) or sea-bass (B2) diet grew significantly

faster (SGR: 0.74 and 0.65) than those fed salmonid diets (A3,A4) (P < 0.05) (Table 3). Furthermore, survival rates weresignificant in tench fed either the eel (B1, 82.7%) or sea-bass(B2, 86.7%) compared with tench fed salmonid diets (A3,

37.3% and A4, 38.7%).

The mode of feed supply (automatic vs manual) studied inexperiment A had no significant effect on tench growth (length

or weight).No significant differences among diets were found in Fulton’s

index (K) or in SGR indexes (Table 3). Changes in wet BW and

condition factor during the diet experiment (Figs. 1 and 2)showed no significant differences for the A1–A4 groups.Finally, no interaction was found between diet type and

feeding type in any of the traits studied.

The mean wet BW for groups fed on eel or sea-bass dietswere, from the third measurement on day 30 until the end of thestudy, significantly greater than the trout diet groups (Fig. 3).

Groups B1 and B2 (eel and sea-bass) were the only groupsshowing an increase in condition factor (Fig. 4). In groups A3and A4, the K index decreased, falling to a mean value lower

than 1.Although no significant differences were detected between

automatic and manual feeders distributing the trout diets, wecannot predict if this would also be the case when using high

quality diets such as eel or sea-bass. Thus we recommend thatfurther trials be conducted to compare growth and survival of

Table 1Experimental groups of juvenile tench, their food, and method of foodadministration

Group Food Supply

A1 Trout starter AutomaticA2 Trout first age AutomaticA3 Trout starter ManualA4 Trout first age ManualB1 Eel ManualB2 Sea-bass Manual

Table 2Diet compositions expressed in percentage and energy in cal/g

DietDrymatter Ash

Crudeprotein Fat Energy

Eel B1 95.46 10.7 52.14 15.93 22.18Sea-bass B2 96.13 9.77 50 19.89 23.69Trout starter A1, A3 94.93 13.42 47.84 14.46 22.58Trout first age A2, A4 96.40 10.06 46.25 18.93 21.54

Group Final length (75 days) Final weight SGR K S% n

A1Trout starter, automatic 6.14 ± 0.56 2.15 ± 0.65 )0.18 0.98 46.0 23

A2Trout first age, automatic 6.25 ± 0.49 2.09 ± 0.57 )0.11 0.93 57.0 29

A3Trout starter, manual 6.18 ± 0.42 2.19 ± 0.45 )0.22 0.93 37.3 19

A4Trout first age, manual 6.00 ± 0.68 1.96 ± 0.23 )0.23 0.91 38.7 19

B1Eel, manual 6.53 ± 0.27 3.49 ± 0.39 0.65 1.25 82.7 41

B2Sea-bass, manual 6.58 ± 0.36 3.63 ± 0.41 0.74 1.27 86.7 43

Table 3Final TL, weight, SGR, conditionfactor, and survival for juvenile tenchin six experimental groups. SGRsexpressed as SGR ¼ (le WT)le Wt)/T;condition factor K ¼ W/ L3, andsurvival (S) in %. n ¼ number ofdeterminations for each data set

1.92

2.12.22.32.42.52.6

1 15 30 45 60 75

Time (d)

Wei

ght (

g)A1 trout starter automatic A2 trout first age automaticA3 trout first age manual A4 trout first age manual

Fig. 1. Changes in mean wet weight for juvenile tench (expt.1: A1-A4).A1, trout starter, automatic; A2, trout first age, automatic; A3, troutstarter, manual; A4, trout first age, manual

0.8

0.9

1.0

1.1

1 15 30 45 60 75

Time (d)

K

A1 trout starter automatic A2 trout first age automatic

A3 trout starter manual A4 trout first age manual

Fig. 2. Changes in condition factor of juvenile tench in groups A1-A4(K=100 L3/W) in experiment 1

150 M. Quiros et al.

juvenile tench fed eel and sea-bass administered by bothautomatic and manual feeders.

Discussion

Previous studies have consistently documented the relativelylow growth rate of tench under controlled conditions com-

pared with other cultivated cyprinid species (Steffens, 1995).Survival rates are also lower (Quiros and Alvarino, 1998).In contrast, the results of the present study show that eel or

sea-bass diets can be used alone for on-growing juvenile tenchunder controlled conditions; the salmonid diets frequentlyused in commercial farms should be avoided because of the

poor growth rates and high mortalities.The growth and survival rates of juveniles fed dry eel or sea-

bass diets could be further improved by the inclusion of smallquantities of live cladocerans (Daphnia sp.) (Quiros and

Alvarino, 1998) with no excessive increases in production costs.The literature indicates that temperatures between 28 and

31�C allow optimal growth of juvenile tench reared on live or

mixed diets (Wolnicki and Gorny, 1991; Wolnicki andKorwin-Kossakowski, 1993). Our results, however, wereobtained at much lower temperatures (mean 22 ± 2�C), thusone could expect that even better growth rates might be

achieved if eel and sea-bass diets were given to fish maintainedat higher temperatures.

In previous studies (S. Juan et al., 1999), high protein dietswere not only associated with high initial growth rates, butalso high mortalities. However, in our study, all diets had high

protein levels (Table 2); two of these, the eel and the sea-bassdiets, resulted in very high growth rates and low mortalities.Therefore, high protein levels alone could not have beenresponsible for the high mortalities; the types of protein

content should also be considered.Additionally, in the present study, the salmonid diets were

less well accepted by the fish and uneaten food caused

deterioration of the water quality of rearing tanks. To avoidthese problems, attention as to palatability, pellet waterstabilization, and origin of raw materials should be given

during the production process. These conclusions are inagreement with results obtained by Sierra et al. (1995), whoshowed that tench initially gained weight with trout pellets butthat the tendency decreased during the study.

There is a high demand for tench in Spain, thus improve-ments in the efficiency of tench culture are of interest to fishfarmers. Use of eel and sea-bass diets for juvenile tench show

good growth rates and survival. Increasing water temperaturesabove 22�C and the addition of Daphnia spp. as a supplementwill also increase the final results. In future experiments it

might be desirable to formulate an experimental diet accordingto the results obtained in this study, increasing water temper-atures and also identifying the convenience of manual vs

automatic feeding.

Acknowledgements

This study was supported by the Comision Interministerial deCiencia y Tecnologıa (C.I.C.Y.T.) Project AGF 97-0977.

References

Association of Official Analytical Chemist (AOAC), 1990: Officialmethods of analysis, 15th edn. AOAC, Washington, DC, USA.

Quiros, M., 1997: Growth of tench (Tinca tinca L.) (Pisces Cyprinidae)under culture controlled conditions. PhD Thesis. UniversidadPolitecnica de Madrid, Madrid.

Quiros, M.; Alvarino, J. M. R., 1998: Growth of tench (Tinca tinca L.)fed with and without the addition of the cladoceran Daphnia. Pol.Arch. Hydrobiol. 45, 447–451.

SAS/STAT, 1987: Guide for personal computers, version 6. SAS Inst.Inc., Cary, NC, USA.

Sierra, A.; Saez-Royuela, M.; Carral, J. M.; Celada, J. D.; Gaudioso,V. R.; Munoz, C.; Perez, J. R., 1995: Response of tench feddifferent diets under intensive conditions. Pol. Arch. Hydrobiol.42, 207–210.

S. Juan, L. D.; Martın-Tereso, J.; Lopez, R.; Bertrand, B.; Jover, M.;Alvarino, J. M. R., 1999: Respuesta productiva de alevines detenca alimentados con piensos con diferentes contenidos de grasay proteına. En: Abstract del 7� Congreso Nacional de Acuicul-tura. G. Canaria, May 19–21, 1999, 89pp.

Steffens, W., 1995: The tench, a neglected pond fish species. Pol. ArchHidrobiol. 42, 161–180.

Wolnicki, J.; Gorny, W., 1991: Comparison of the suitability of threecarp starters for rearing tench larvae under controlled conditions.Komunicat Rybackie 1, 17.

Wolnicki, J.; Korwin-Kossakowski, M., 1993: Survival and growth oflarval and juvenile tench fed different diets under controlledconditions. Aquacult. and Fish Manage. 24, 707–713.

Author’s address: M. Quiros, Departmento de Production Animal,Escuela Tecnica Superior de Ingenieros Agrono-mos, Universidad Politecnica de Madrid, CiudadUniversitaria, E-28040 Madrid, Spain.E-mail: mquiroz@pan.etsia.upm.es

1.7

2

2.3

2.6

2.9

3.2

3.5

3.8

1 15 30 45 60 75

Time (d)

Wei

ght (

g)A3 Trout starter manual A4 trout first age manualB1 Eel manual B2 Sea-bass manual

Fig. 3. Changes in wet body weight for juvenile tench in experiment 2

1.7

2

2.3

2.6

2.9

3.2

3.5

3.8

1 15 30 45 60 75

Time (d)

Wei

ght (

g)

A3 trout starter manual A4 trout first age manual

B1 eel manual B2 sea-bass manual

Fig. 4. Changes in condition factor of juvenile tench in experiment 2(K=100 L3/W)

Survival and changes in growth of juvenile tench 151