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Mortality structures population size characteristics of juvenile yellowtail kingfish Seriola lalandi reared at different densities

Moran, Damian LU ; Smith, Cea K.; Lee, Peter S. and Pether, Stephen J. (2011) In Aquatic Biology 11(3). p.229-238
Abstract
A study was undertaken to measure the effects of conspecific density on the growth, mortality and deformity rate of yellowtail kingfish Seriola lalandi Valenciennes during the first feeding period. Newly hatched larvae were stocked in replicate tanks at initial densities of 40, 60 and 100 ind. l(-1) until 30 d post-hatch (DPH). Live prey was administered at frequent intervals in an effort to maintain absolute prey density for all treatments. There was a negative relationship between conspecific density and mean individual length during the first half of the trial, which was attributed to food depletion between supplementary feedings at higher conspecific densities. The effect size (partial eta-squared) of conspecific density decreased... (More)
A study was undertaken to measure the effects of conspecific density on the growth, mortality and deformity rate of yellowtail kingfish Seriola lalandi Valenciennes during the first feeding period. Newly hatched larvae were stocked in replicate tanks at initial densities of 40, 60 and 100 ind. l(-1) until 30 d post-hatch (DPH). Live prey was administered at frequent intervals in an effort to maintain absolute prey density for all treatments. There was a negative relationship between conspecific density and mean individual length during the first half of the trial, which was attributed to food depletion between supplementary feedings at higher conspecific densities. The effect size (partial eta-squared) of conspecific density decreased considerably during the trial, to the point where the initial stocking density had no discernible effect on cohort growth or mortality rate. The apparent morphological deformity rate ranged from 17 to 32%, but did not differ between treatments. Jaw malformations were the most commonly observed deformity (12 to 30%). The weights of juveniles at the end of the trial were log-normally distributed, with some disproportionately large individuals skewing the weight distributions. There was substantial variation in mortality between and within treatments (74 to 97%), and the conspecific densities of each replicate at 30 DPH did not reflect the relative ordering of the initial treatments. Median individual weight was highly correlated with mortality and weight variance, and the positive skewness of populations decreased as mortality increased. Both trends indicated a strong population size-structuring mechanism. Given the controlled experimental conditions the size-structuring mechanism was not predation or cannibalism. Differential feeding success and an unidentified size-specific mortality agent are hypothesized to be the mechanisms by which mortality was able to strongly influence population size distributions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cohort size distribution, Deformity rate, Growth variation, Juvenile, mortality
in
Aquatic Biology
volume
11
issue
3
pages
229 - 238
publisher
Inter-Research
external identifiers
  • wos:000287668300004
  • scopus:79952333581
ISSN
1864-7782
DOI
10.3354/ab00314
language
English
LU publication?
yes
id
1219e134-8236-44bd-a3f4-6e1d0cde0fd5 (old id 1876469)
date added to LUP
2011-04-18 10:29:31
date last changed
2017-10-22 03:10:14
@article{1219e134-8236-44bd-a3f4-6e1d0cde0fd5,
  abstract     = {A study was undertaken to measure the effects of conspecific density on the growth, mortality and deformity rate of yellowtail kingfish Seriola lalandi Valenciennes during the first feeding period. Newly hatched larvae were stocked in replicate tanks at initial densities of 40, 60 and 100 ind. l(-1) until 30 d post-hatch (DPH). Live prey was administered at frequent intervals in an effort to maintain absolute prey density for all treatments. There was a negative relationship between conspecific density and mean individual length during the first half of the trial, which was attributed to food depletion between supplementary feedings at higher conspecific densities. The effect size (partial eta-squared) of conspecific density decreased considerably during the trial, to the point where the initial stocking density had no discernible effect on cohort growth or mortality rate. The apparent morphological deformity rate ranged from 17 to 32%, but did not differ between treatments. Jaw malformations were the most commonly observed deformity (12 to 30%). The weights of juveniles at the end of the trial were log-normally distributed, with some disproportionately large individuals skewing the weight distributions. There was substantial variation in mortality between and within treatments (74 to 97%), and the conspecific densities of each replicate at 30 DPH did not reflect the relative ordering of the initial treatments. Median individual weight was highly correlated with mortality and weight variance, and the positive skewness of populations decreased as mortality increased. Both trends indicated a strong population size-structuring mechanism. Given the controlled experimental conditions the size-structuring mechanism was not predation or cannibalism. Differential feeding success and an unidentified size-specific mortality agent are hypothesized to be the mechanisms by which mortality was able to strongly influence population size distributions.},
  author       = {Moran, Damian and Smith, Cea K. and Lee, Peter S. and Pether, Stephen J.},
  issn         = {1864-7782},
  keyword      = {Cohort size distribution,Deformity rate,Growth variation,Juvenile,mortality},
  language     = {eng},
  number       = {3},
  pages        = {229--238},
  publisher    = {Inter-Research},
  series       = {Aquatic Biology},
  title        = {Mortality structures population size characteristics of juvenile yellowtail kingfish Seriola lalandi reared at different densities},
  url          = {http://dx.doi.org/10.3354/ab00314},
  volume       = {11},
  year         = {2011},
}