EurekaMag.com logo
+ Site Statistics
References:
47,893,527
Abstracts:
28,296,643
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

The effects of fry rearing density on hatchery performance, fin condition, and agonistic behavior of rainbow trout Oncorhynchus mykiss fry






Journal of the World Aquaculture Society 27(3): 264-274

The effects of fry rearing density on hatchery performance, fin condition, and agonistic behavior of rainbow trout Oncorhynchus mykiss fry

Rainbow trout Oncorhynchus mykiss fry were reared at four densities ranging from 10,800 to 43,926 fish/m-3 (9.91 to 37.60 kg/ml) during an initial feeding period of 35 d. Each of the four initial density treatments were then split into high (3,780 fish/m-3) and low (1,890 fish/m-3) density groups and reared in outdoor raceways for an additional 74 d. A necropsy-based general health and condition assessment indicated that hematocrit, plasma protein, and the thymus index were significantly elevated in the outdoor high density group. Changes in these variables were unrelated to the initial rearing density, except for plasma protein which decreased as the initial density increased at low densities. Other necropsy variables indicated normal, healthy fish. Agonistic behavior was assessed at 4, 9 and 13 wk of age by observing the number of aggressive chases in paired and group (five fish) trials. The number of chases generally increased with age, although the difference between 9 and 13 wk was variable. Feeding did not elicit more chases in this study except for 9-wk-old fry. Initial rearing density did not have any impact on the number of chases at 4 or 13 wk, but at 9 wk the number of chases increased with initial density for the group tests. Relative fin length measurements of all fins except the adipose indicated no combination of initial density and outdoor density was superior to another for reducing fin erosion. This study indicated that rainbow trout fry may be reared at initial densities approaching 44,000 fish/m-3 (Piper density index of 1.1) without negatively affecting growth and fin condition or inducing higher levels of agonistic behavior later on.

Accession: 002984917

DOI: 10.1111/j.1749-7345.1996.tb00608.x

Download PDF Full Text: The effects of fry rearing density on hatchery performance, fin condition, and agonistic behavior of rainbow trout Oncorhynchus mykiss fry



Related references

Marchetti, M.P.; Nevitt, G.A., 2003: Effects of hatchery rearing on brain structures of rainbow trout, Oncorhynchus mykiss. In this study, we contrast brain morphology from hatchery and wild reared stocks to examine the hypothesis that in salmonid fishes, captive rearing produces changes in brain development. Using rainbow trout, Oncorhynchus mykiss, as a model, we mea...

Wagner, E.J.; Routledge, M.D.uglas; Intelmann, S.S., 1996: Assessment of demand feeder spacing on hatchery performance, fin condition, and size variation of rainbow trout Oncorhynchus mykiss. Fingerling rainbow trout, Oncorhynchus mykiss, were fed for 133 d by one of three feeding methods: one demand feeder per 5.5 m of raceway, 2 demand feeders per 5.5 m of raceway, and hand-fed controls. Mean weight, total length, mortality, and feed...

Janhunen, M.; Kause, A.; Vehviläinen, H.; Nousiainen, A.; Koskinen, H., 2014: Accounting for early rearing density effects on growth in the genetic evaluation of rainbow trout, Oncorhynchus mykiss. In fish breeding, full-sib families are often kept in separate tanks until individuals are large enough to be tagged and pooled. This practice induces substantial environmental variation common to full sibs (VFS) in BW. We used multigeneration dat...

Peter Vilhelm Skov; Bodil Katrine Larsen; Michael Frisk; Alfred Jokumsen, 2011: Effects of rearing density and water current on the respiratory physiology and haematology in rainbow trout, Oncorhynchus mykiss at high temperature. Rearing fish at high densities is considered stressful. For many species this leads to poor feed conversion, decreased feed intake and reduced growth, possibly caused by a change in energy partitioning or expenditure. To test this theory, we exami...

Makinen T.; Ruohonen K., 1990: The effect of rearing density on the growth of finnish rainbow trout oncorhynchus mykiss walbaum 1792. One-year-old Finnish rainbow trout were reared for six months at eight different densities with between 16 and 111 specimens per m2 and between 37 and 493 specimens per m3, respectively. Average initial weights varied between 125 and 148 grammes a...

Sloman, K.A.; Baker, D.W.; Ho, C.G.; McDonald, D.G.; Wood, C.M., 2003: The effects of trace metal exposure on agonistic encounters in juvenile rainbow trout, Oncorhynchus mykiss. The effects of five trace metals, copper, cadmium, nickel, zinc and lead (presented as soluble salts) on the ability of juvenile rainbow trout to form social relationships were investigated. Comparable concentrations of the five metals in relation...

Sloman, K.A.; Baker, D.W.; Ho, C.G.; McDonald, D.G.; Wood, C.M., 2003: The effects of trace metal exposure on agonistic encounters in juvenile rainbow trout, Oncorhynchus mykiss. The effects of five trace metals, copper, cadmium, nickel, zinc and lead (presented as soluble salts) on the ability of juvenile rainbow trout to form social relationships were investigated. Comparable concentrations of the five metals in relation...

Hou, Z-Shuai.; Wen, H-Shen.; Li, J-Fang.; He, F.; Li, Y.; Tao, Y-Xiong., 2016: Hypothalamus-pituitary-gonad axis of rainbow trout (Oncorhynchus mykiss) during early ovarian development and under dense rearing condition. The objective of this study was to determine the hypothalamus-pituitary-gonad (HPG) axis of female rainbow trout (Oncorhynchus mykiss) during early ovarian development and under high rearing density. Trouts were sampled from 240 (ovarian stage II)...

Wagner, E.J.; Jeppsen, T.; Arndt, R.; Routledge, M.D.uglas; Bradwisch, Q., 1997: Effects of rearing density upon cutthroat trout hematology, hatchery performance, fin erosion, and general health and condition. Cutthroat trout of the Bear Lake Bonneville strain, Oncorhynchus clarki utah, were used in two separate density experiments. In the first, fish were reared for 212 d in outdoor raceways at four densities; fish were allowed to grow into their final...

Sanchez, J.G.; Speare, D.J.; MacNair, N.; Johnson, G., 1997: Effect of prophylactic chloramine-T treatment on growth performance and condition indices of rainbow trout (Oncorhynchus mykiss). Healthy trout exposed to chloramine-T at 10 mg/litre for an hour, twice weekly, for an 11-week growth period showed impaired growth. This was due to a depression in feed conversion and a slight depression in appetite. There were no signs of clinic...