Method for Quantifying Degree of Fin Erosion

Kindschi, Greg A.

doi:10.1577/1548-8640(1987)49<314:mfqdof>2.0.co;2

Cited by 55 publications

(37 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Along with tank biomass, length to the nearest millimeter, weight to the nearest 0.01 g, fin lengths to the nearest 0.01 mm, and weights of the spleen, liver, and viscera to the nearest 0.001 g were recorded from five fish randomly selected from each tank. The following equations were used: Total tank weight gain = final tank weight ‐ initial tank weight Feed conversion ratio (FCR) = feed fed/weight gain Condition factor (K) = 100 x [weight (g)/length (cm) 3 ] Splenosomatic index (SSI; 100%) = 100 x [spleen weight (g)/whole fish weight (g)] Hepatosomatic index (HSI;%) = 100 x [liver weight (g)/whole fish weight (g)] Viscerosomatic index (VSI;%) = 100 x [Viscera weight (g)/whole fish weight (g)] Fin index = 100 x [fin length (mm)/total body length (mm)] (Kindschi ) …”

Section: Methodsmentioning

confidence: 99%

An Evaluation of Vertically Suspended Environmental Enrichment Structures during Rainbow Trout Rearing

2018

View full text Add to dashboard Cite

Environmental enrichment is the addition of substrate or structural complexity to typically sterile culture environments, but the effects of enrichment on fish rearing performance are relatively unknown. This 127‐d study examined the growth and condition of juvenile Rainbow Trout Oncorhynchus mykiss reared in near‐fully covered circular tanks (1.8 m diameter) with three novel environmental treatments: (1) eight vertically suspended nylon strings with seven colored (6.4 cm diameter) plastic spheres (high density), (2) five vertically suspended strings with seven colored plastic spheres (low density), and (3) a mixture of five vertically suspended colored plastic spheres and nine vertically suspended aluminum rods. Near‐fully covered tanks without enrichment were used as a control. Weight gain, feed conversion ratio, individual fish length, and fish weight were significantly improved in environmentally enriched tanks compared with those features in the unenriched control. Among all of the treatments, the tanks of fish with high‐density spheres had significantly higher ending tank weights (i.e., total weight of fish in tank) and weight gain, both of which were nearly 65% and 75% greater, respectively, than in the control tanks. However, high density spheres also interfered with the self‐cleaning nature of the circular tanks. No significant differences in splenosomatic indices, viscerosomatic indices, hepatosomatic indices, and relative fin lengths were observed among the three enrichment treatments. Based on the results of this study, the use of either low‐density spheres or a mix of rods and spheres is recommended during the rearing of juvenile Rainbow Trout in circular tanks.

show abstract

Section: Methodsmentioning

confidence: 99%

An Evaluation of Vertically Suspended Environmental Enrichment Structures during Rainbow Trout Rearing

2018

View full text Add to dashboard Cite

show abstract

“…This is slightly modified from the model presented by Kindschi (1987) using total length of the fish. Owing to erosion of the caudal fins at variable levels, we estimated that, in the present studies, fish fork length was more adequate for calculation of DFI.…”

Section: Methodsmentioning

confidence: 99%

Fin condition and growth among rainbow trout reared at different sizes, densities and feeding frequencies in high-temperature re-circulated water

Rasmussen¹,

Larsen

Jensen³

2007

Aquacult Int

View full text Add to dashboard Cite

Rainbow trout were studied at different rearing densities, fish sizes and feeding frequencies so that we could evaluate the effect of these parameters on fin condition, growth and feed utilisation. In one study, two sizes of rainbow trout (18-70 g or 48-125 g), fed to near satiation at 17.7°C, were examined at two rearing densities (11-41 kg m -3 or 21-92 kg m -3 ). This study showed that the anal fin was healthier (P < 0.05) at low densities. In the second study rainbow trout were again fed to near satiation and grown from 50 g to 125 g in 16.4°C water, and they were fed either once daily or three times daily at two densities (18-45 kg m -3 or 54-124 kg m -3 ). Rainbow trout growth and feed utilisation were slightly but significantly (P < 0.05) reduced at high densities, while dorsal fin condition, surprisingly, was better (P < 0.0001) at the high densities. Possible explanations to these findings are discussed. Condition of the left pectoral fin was improved at once daily feeding (P < 0.05) compared with three feedings per day, at which fights for feed possibly are more frequent.

show abstract

“…aggressive nipping or abrasion (with conspecifics or the walls of the rearing system), or poor handling. Further erosion may then result from continued physical processes and/or additional environmental factors such as water quality (ammonia and alkalinity), sunlight, and pathogen infection (Kindschi, 1987;Kindschi et al, 1991c;Bosakowski & Wagner, 1994b). Density can theoretically promote the initial cause as well as the secondary infection-due to deterioration in water quality and increased potential for pathogen transmission.…”

Section: Fin and Body Injurymentioning

confidence: 99%

The relationships between stocking density and welfare in farmed rainbow trout

Ellis

North

Scott

et al. 2002

Journal of Fish Biology

535

201

View full text Add to dashboard Cite

There is increasing public, governmental and commercial interest in the welfare of intensively farmed fish and stocking density has been highlighted as an area of particular concern. Here we draw scientific attention and debate to this emerging research field by reviewing the evidence for effects of density on rainbow trout. Although no explicit reference to ' welfare ' has been made, there are 43 studies which have examined the effects of density on production and physiological parameters of rainbow trout. Increasing stocking density does not appear to cause prolonged crowding stress in rainbow trout. However, commonly reported effects of increasing density are reductions in food conversion efficiency, nutritional condition and growth, and an increase in fin erosion. Such changes are indicative of a reduced welfare status-although the magnitude of the effects has tended to be dependent upon study-specific conditions. Systematic observations on large scale commercial farms are therefore required, rather than extrapolation of these mainly small-scale experimental findings. There is dispute as to the cause of the observed effects of increasing density, with water quality deterioration and/or an increase in aggressive behaviour being variously proposed. Both causes can theoretically generate the observed effects of increasing density, and the relative contribution of the two causes may depend upon the specific conditions. However, documentation of the relationship between density and the effects of aggressive behaviour at relevant commercial densities is lacking. Consequently only inferential evidence exists that aggressive behaviour generates the observed effects of increasing density, whereas there is direct experimental evidence that water quality degradation is responsible. Nevertheless, there are contradictory recommendations in the literature for key water quality parameters to ensure adequate welfare status. The potential for welfare to be detrimentally affected by non-aggressive behavioural interactions (abrasion, collision, obstruction) and low densities (due to excessive aggressive behaviour and a poor feeding response) have been largely overlooked. Legislation directly limiting stocking density is likely to be unworkable, and a more practical option might be to prescribe acceptable levels of water quality, health, nutritional condition and behavioural indicators.

show abstract

Method for Quantifying Degree of Fin Erosion

Cited by 55 publications

References 5 publications

An Evaluation of Vertically Suspended Environmental Enrichment Structures during Rainbow Trout Rearing

An Evaluation of Vertically Suspended Environmental Enrichment Structures during Rainbow Trout Rearing

Fin condition and growth among rainbow trout reared at different sizes, densities and feeding frequencies in high-temperature re-circulated water

The relationships between stocking density and welfare in farmed rainbow trout

Contact Info

Product

Resources

About