An empirical evaluation of several univariate methods that adjust for size variation in morphometric data

Reist, James D.

doi:10.1139/z85-213

Cited by 464 publications

(340 citation statements)

References 25 publications

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“…Body condition for captured fish was estimated by the residuals from a linear regression of weight on fork length, which has been demonstrated to remove the effects of size variation and is considered an appropriate condition index for the weight-length relationship in fish (Reist, 1985;Cone, 1989;Sutton et al, 2000). If significance was observed in relation to angling duration, one-way analysis of variance (ANOVA) was used to determine whether there were significant changes over time (by minute of angling duration) in extended capture fish.…”

Section: Methodsmentioning

confidence: 99%

Physiological response of wild rainbow trout to angling: impact of angling duration, fish size, body condition, and temperature

2005

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This study evaluated the immediate physiological response of wild rainbow trout to catch-and-release angling in the Alagnak River, southwest Alaska. Information was recorded on individual rainbow trout (n = 415) captured by angling including landing time and the time required to remove hooks (angling duration), the time to anesthetize fish in clove oil and withdraw blood, fish length and weight, and water temperature at capture locations. Plasma cortisol, glucose, ions (sodium, potassium, chloride), and lactate were analyzed to determine the effects of angling duration, fish size, body condition, and temperature. Levels of plasma ions did not change significantly during the observed physiological response and levels of plasma glucose were sometimes influenced by length (2000, 2001), body condition (2001), or temperature (2001). Levels of plasma cortisol and lactate in extended capture fish (angling duration greater than 2 min) were significantly higher than levels in rapid capture fish (angling duration less than 2 min). Rapid capture fish were significantly smaller than extended capture fish, reflecting that fish size influenced landing and handling times. Fish size was related to cortisol and lactate in 2002, which corresponded to the year when larger fish were captured and there were longer landing times. Body condition (i.e., weight/length regression residuals index), was significantly related to lactate in 2000 and 2001. Water temperatures were higher in 2001 (mean temperature ± S.E., 13 ± 2 • C) than in 2002 (10 ± 2 • C), and fish captured in 2001 had significantly higher cortisol and lactate concentrations than fish captured in 2002. The pattern of increase in plasma cortisol and lactate was due to the amount of time fish were angled, and the upper limit of the response was due to water temperature. The results of this study indicate the importance of minimizing the duration of angling in order to reduce the sublethal physiological disturbances in wild fish subjected to catch-and-release angling, particularly during warmer water temperatures. It is also important to note that factors such as fish size may influence both the duration of angling and subsequent physiological response.

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Section: Methodsmentioning

confidence: 99%

Physiological response of wild rainbow trout to angling: impact of angling duration, fish size, body condition, and temperature

2005

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“…This transformation best reflected shape variation among groups independently of size (Reist 1985). The standardised morphometric characters showed no significant correlation with standard length (P!0.05 for all characters), indicating that the allometric transformation had successfully removed the length effects.…”

Section: Morphometric Analysismentioning

confidence: 92%

Evidence for discrete subpopulations of sea perch (Helicolenus ercoides) across four fjords in Fiordland, New Zealand

Lawton

Wing

Lewis

2010

New Zealand Journal of Marine and Freshwater Research

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In coastal populations of invertebrates and fishes, the distribution of discrete subpopulations is influenced by adult and larval dispersal, as well as by the effects of habitat heterogeneity on site fidelity or connectivity. Here, we examine evidence for spatial structure of sea perch, Helicolenus percoides, populations among four fjords in the Fiordland region of southwestern New Zealand. We examine patterns in adult morphology, length-at-age, d13 C and d 15N of muscle tissue, and trace elemental composition of whole otoliths as proxies for population isolation among the four inner fjord regions. A multivariate analysis of morphometrics reveals significant differences among populations from each of the four sites, suggesting existence of four distinct subpopulations. These patterns are consistent with observed differences in d 13 C and d 15 N, and length-at-age estimates among the four subpopulations. Differences in whole otolith concentrations of Sr, Ba, Mg and Li, and high classification scores based on the whole otolith elemental fingerprint are also consistent with significant subdivision among areas. Patterns across all four markers are consistent with discrete subpopulation structure of adult sea perch among the four study sites. These data indicate that the newly implemented network of marine protected areas in Fiordland is likely to contain discrete populations of sea perch.

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“…Measurements of each morphometric character were standardized to fish size (SL) in accordance with Reist (1985) to remove size-effect using percentage standard length as it follows: Mn=(Mo/SL)%, where: Mo is the original measurement; and SL is the standard length.…”

Section: Morphometric Data Analysismentioning

confidence: 99%

Genetic Differentiation Studies among Natural Populations of <i>Tilapia zillii</i>

2015

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The population structure of Tilapia zillii (Gervais 1848) from three reservoirs in Nigeria, Osun State (Opa, Osu and Igun) was determined by employing morphological and molecular (Random Amplified Polymorphic DNA) methods. For morphological studies, 25 morphometric measurements and six meristic counts were recorded on 40 individuals within each population. Principal Component Analysis (PCA) was performed on the morphometric and meristic data using the PAST software. For RAPD studies, genomic DNA was extracted from caudal fin tissue using CTAB method and five primers were used to initiate PCR amplifications. All the clusters produced by the Principal components analysis (PCA) of the morphometric and meristic parameters overlapped indicating a low level of genetic differentiation between the three populations of T. zillii studied. The UPGMA cluster diagram from RAPD analysis identified two major genotypic groups with inter and intra group relationships. All individuals in the first cluster were from the Osu reservoir, while individuals from Opa and Igun reservoirs constituted the second cluster. Nei's unbiased measure of genetic distances was 0.8532, 0.7321 and 0.7111 for Osu, Igun and Opa populations respectively. This revealed that Opa and Igun populations were genetically closer, while Osu populations is distant from them. The results suggest that the RAPD technique could be used to differentiate populations of T. zillii. However, additional methods such as microsatellite and sequence analysis can be used to maximize the efficiency of genetic differentiation studies.

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An empirical evaluation of several univariate methods that adjust for size variation in morphometric data

Cited by 464 publications

References 25 publications

Physiological response of wild rainbow trout to angling: impact of angling duration, fish size, body condition, and temperature

Physiological response of wild rainbow trout to angling: impact of angling duration, fish size, body condition, and temperature

Evidence for discrete subpopulations of sea perch (Helicolenus ercoides) across four fjords in Fiordland, New Zealand

Genetic Differentiation Studies among Natural Populations of <i>Tilapia zillii</i>

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