Effects of freezing on white perch Morone americana (Gmelin, 1789): Implications for multivariate morphometrics

Patrick Kocovsky

doi:10.1111/jai.12930

Home/Archive/USGS

USGS · 70160787

Effects of freezing on white perch Morone americana (Gmelin, 1789): Implications for multivariate morphometrics

Patrick Kocovsky

View original source ↗Export metadata ↓

Abstract

This study tested the hypothesis that duration of freezing differentially affects whole-body morphometrics of a derived teleost. Whole-body morphometrics are frequently analyzed to test hypotheses of different species, or stocks within a species, of fishes. Specimens used for morphometric analyses are typically fixed or preserved prior to analysis, yet little research has been done on how fixation or preservation methods or duration of preservation of specimens might affect outcomes of multivariate statistical analyses of differences in shape. To determine whether whole-body morphometrics changed as a result of freezing, 23 whole-body morphometrics of age-1 white perch ( Morone americana ) from western Lake Erie (n = 211) were analyzed immediately after capture, after being held on ice overnight, and after freezing for 100 or 200 days. Discriminant function analysis revealed that all four groups differed significantly from one another (P < 0.0001). The first canonical axis reflected long-axis morphometrics, where there was a clear pattern of positive translation along this axis with duration of preservation. Re-classification analysis demonstrated fish were typically assigned to their original preservation class except for fish frozen 100 days, which assigned mostly to frozen 200 days. Morphometric comparisons using frozen fish must be done on fish frozen for identical periods of time to avoid biases related to the length of time they were frozen. Similar experiments should be conducted on other species and also using formalin- and alcohol-preserved specimens.

Explore related subjects

Journal of Applied Ichthyology Article

Source-reported bounding extent: 41.38299120166604° to 42.633958722673164° latitude; -83.48236083984375° to -81.06262207031249° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Patrick Kocovsky. 2015-10-28. Effects of freezing on white perch Morone americana (Gmelin, 1789): Implications for multivariate morphometrics. https://doi.org/10.1111/jai.12930

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2024

Length-weight relationships of native and non-native fishes in the lower Red River catchment, USA

Length-weight relationships are useful for stock assessments and modeling alternative conservation and management strategies for both native and non-native fishes. We developed length-weight relationships for 18 native and non-native riverine fishes in the lower Red River catchment. Fishes were sampled in the summer and autumn seasons between May 2021 and March 2024 via electrofishing and gill nets. Measurements for each specimen consisted of total length (mm) and weight (g). We provide L-W relationships for 14 native fishes consisting of 5 families (Lepisosteidae, Catostomidae, Ictaluridae, Sciaenidae, and Polyodontidae) and 4 non-native species belonging to the family Cyprinidae. We collected 6,845 individuals ranging from 67 alligator gar to 1,848 smallmouth buffalo. All the L-W relationships were significant ( p < 0.05), and the majority (72% of species) of relationships between length and weight had r 2 values > 0.70. Our findings provide insight into the L-W relationships of riverine fishes and can be useful for modeling alternatives targeted at native fishes of recreational value and the removal efforts of non-native fishes.

Arkansas, Oklahoma, Texas↗

USGS2024

Validation of a molecular sex marker in three sturgeons from eastern North America

Despite the importance of sex-specific information for sturgeon conservation and management, sex identification has been a major challenge outside of mature adults on spawning grounds. Recent work identified a sex-specific locus ( AllWSex2 ) that appears to be broadly conserved across many Acipenserids, but the assay was not validated for all species within the family. We tested the AllWSex2 marker in three sturgeon taxa (shortnose sturgeon Acipenser brevirostrum , Gulf sturgeon A. oxyrhinchus desotoi , and Atlantic sturgeon A. oxyrhinchus oxyrhinchus ) from the Atlantic and Gulf of Mexico Coasts of North America to validate its use for sex identification. Our results indicate AllWSex2 is conserved in all three taxa, presenting a new opportunity to derive sex-specific information from tissue samples, which are routinely collected from these taxa. We found high concordance (range: 97–100%) between genotypic and phenotypic/histological methods, suggesting the assay is broadly effective. However, the small amount of discordance between the methods (< 3%) suggests further refinement may be possible.

Journal of Applied Ichthyology↗

USGS2024

Black carp Mylopharyngodon piceus (Richardson, 1846) mouth gape and size preference of a bivalve prey

Black carp Mylopharyngodon piceus (Richardson, 1846) have been widely used as biological control of snails in aquaculture and were imported to the United States in the 1970s and 1980s for this purpose. Prior research emphasizes the species’ propensity to control gastropods, but since subsequent escape and establishment of black carp in portions of the Mississippi River Basin, concerns now focus on the numerous endangered and endemic bivalve species upon which black carp may predate. Black carp mouth gape may limit predation on larger bivalves, but bite force is also a factor. We used regression of fish length to mouth gape of wild-caught black carp and compared these results to tank forage size preference trials with bivalve prey Corbicula fluminea clams. Wild-caught black carp ranged from 429 to 1580 mm total length, a size range larger than measured in previous studies. Regression of fish length and mouth gape indicated greater variability among sizes, as expected from wild versus cultured populations. Clam consumption was size-dependent. Black carp commonly engulfed but did not consume the largest clams in tank feeding trials. Shell width was a better predictor of successful consumption than length or height. Predation was restricted at sizes less than the mouth gape of test black carp as observed by individuals engulfing but failing to consume prey. This result indicates that either bite force or the pharyngeal apparatus gape (i.e., the distance between the pharyngeal teeth and keratinous pad) limited successful crushing of engulfed shells. Bivalve predation by black carp is limited by both a fish’s ability to engulf prey and the ability to fracture the shell of larger prey items that cannot be broken or swallowed whole. The results of this research may be used to assess potential prey sizes of wild black carp and anticipated effects of predation on bivalve communities.

Journal of Applied Ichthyology↗