Sexual differences in accumulation of mercury in four species of centrarchid fishes

1988 ◽  
Vol 66 (4) ◽  
pp. 944-949 ◽  
Author(s):  
Paul F. Nicoletto ◽  
Albert C. Hendricks
Keyword(s):  
Lepomis Macrochirus ◽  
Mercury Content ◽  
Lepomis Gibbosus ◽  
South Fork ◽  
The South ◽  
Male And Female ◽  
Rock Bass ◽  
Males And Females ◽  
Redbreast Sunfish ◽  
Ambloplites Rupestris

A 3-year study of fish from the South River, and the South Fork of the Shenandoah River, and the Shenandoah River in Virginia revealed significant differences in the muscle mercury content of males and females. Female rock bass, Ambloplites rupestris, redbreast sunfish, Lepomis auritus, pumpkinseed, Lepomis gibbosus, and bluegill, Lepomis macrochirus contained higher levels of mercury than the males of each species. An analysis of these species indicated that sex-related differences in mercury levels were not due to differences in body size but may have been related to the onset of reproduction. For example, mercury levels in 1-year-old male and female redbreast sunfish were not significantly different: females averaged 0.66 μg Hg/g and males averaged 0.63 μg Hg/g. However, at 2 years of age, when redbreast sunfish first reproduce, females contained significantly more mercury than males: females averaged 0.84 μg Hg/g and males averaged 0.60 μg Hg/g. Analysis of the other species yielded similar results.

Epizootiology, pathology, and description of Eustrongylides tubifex (Nematoda: Dioctophymatoidea) in fish

1988 ◽  
Vol 66 (10) ◽  
pp. 2212-2222 ◽  
Author(s):  
Lena N. Measures
Keyword(s):  
Yellow Perch ◽  
Perca Flavescens ◽  
Infected Fish ◽  
Lepomis Gibbosus ◽  
Fourth Stage ◽  
Intermediate Hosts ◽  
Third Stage ◽  
Rock Bass ◽  
Ambloplites Rupestris ◽  
Fish Hosts

In Guelph Lake, a man-made reservoir in Ontario, Canada, prevalence of larval Eustrongylides tubifex in pumpkinseed (Lepomis gibbosus), rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens) was 12.9% and mean intensity ranged from 1 to 1.8. Larvae were encapsulated on the mesentery of fish. Pumpkinseed and yellow perch were the important fish hosts in Guelph Lake as most larvae in these fish were alive. In contrast, 40% of larvae in rock bass were dead and calcified. Third- and fourth-stage larvae from naturally infected fish are described. Larvae in the three species of fish elicited a granulomatous inflammatory reaction. Attempts to transfer third-stage larvae from experimentally infected oligochaetes and third-stage larvae from naturally infected fish to laboratory-reared pumpkinseed were unsuccessful. Fourth-stage larvae from naturally infected fish were transferred successfully to pumpkinseed. Eutropic lakes such as Guelph Lake are particularly suitable enzootic areas because of the abundant populations of tubificid intermediate hosts and the presence of fish hosts such as pumpkinseed and perch. The advanced stage and development of larvae (to the fourth stage) in fish likely represents an adaptation for a parasite that occurs in a migratory host such as Common Mergansers (Mergus merganser), which frequent Guelph Lake for only about 1 month in spring and fall.

Morphological Divergence in the Genus Eptesicus (Microchiroptera: Vespertilionidae) in Western Australia: a Multivariate Approach.

1980 ◽  
Vol 28 (3) ◽  
pp. 457 ◽  
Author(s):  
NA Campbell ◽  
DJ Kitchener
Keyword(s):  
Western Australia ◽  
Canonical Variate ◽  
Morphological Divergence ◽  
Multivariate Approach ◽  
The South ◽  
Male And Female ◽  
North West ◽  
South West ◽  
Variate Analysis ◽  
Males And Females

Analyses of morphological divergence in male and female Eptesicus in Western Australia are detailed. Phenetic differences between individuals at each locality, or nearby groups of localities, are examined for males and females separately, by canonical variate analysis. Populations can be roughly grouped into those of the South-west, North-west-Desert, Pilbara, Kimberley and the Peninsulas. Trends are evident from the analysis of the regional data for external morphological measurements. The South-west populations are referable to Eptesicus regulus Thomas, 1906. The moderately large Northwest-Desert populations are considered part of a general cline of Eptesicus pumilus extending north through the intermediate-sized Pilbara populations to the small Kimberley populations. The Peninsula populations have their greatest phenetic affinities with Eptesicus douglasi. In all populations examined, female Eptesicus tend to be larger than males.

Branching complexity and morphological characteristics of coarse woody structure as lacustrine fish habitat

2005 ◽  
Vol 62 (9) ◽  
pp. 2110-2123 ◽  
Author(s):  
Michael G Newbrey ◽  
Michael A Bozek ◽  
Martin J Jennings ◽  
James E Cook
Keyword(s):  
Littoral Zone ◽  
Yellow Perch ◽  
Fish Habitat ◽  
Lepomis Macrochirus ◽  
Perca Flavescens ◽  
Morphological Characteristics ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Rock Bass ◽  
Ambloplites Rupestris

The objective of this study was to quantify the physical characteristics of coarse woody structure (CWS) as fish habitat in a north temperate lake. Sixteen species of fish were observed in submerged CWS habitat. Branching complexity, distance above the bole, area below the bole, distance to other CWS, and water depth around CWS were significantly related to abundance of schooling cyprinids (Cyprinidae), rock bass (Ambloplites rupestris), smallmouth bass (Micropterus dolomieu), bluegill (Lepomis macrochirus), yellow perch (Perca flavescens), and walleye (Sander vitreus). Branching complexity was the most common characteristic of CWS related to richness, diversity, and total adult abundance of fish taxa, but was not correlated with the total lengths of fish found in submerged trees. Branching-complexity values ranged from 1 (simple) to 500 (moderately complex) in the littoral zone; for comparison, a living riparian conifer had a branching-complexity value of over 1000. Most CWS in the littoral zone was composed of simple trees without branching, but fish tended to inhabit CWS with branching-complexity values greater than 45. This study shows the importance of CWS with fine branching as littoral-zone fish habitat.

Retinal structure relative to feeding in the rock bass (Ambloplites rupestris) and bluegill (Lepomis macrochirus)

1988 ◽  
Vol 66 (12) ◽  
pp. 2840-2846 ◽  
Author(s):  
Mark Williamson ◽  
Allen Keast
Keyword(s):  
Feeding Habits ◽  
Lepomis Macrochirus ◽  
Visual Sensitivity ◽  
Visual Direction ◽  
Fish Feeding ◽  
Chironomid Larvae ◽  
Average Value ◽  
Rock Bass ◽  
Light Gathering ◽  
Ambloplites Rupestris

The morphology and organization of the retina of rock bass (Ambloplites rupestris) and bluegill (Lepomis macrochirus) were investigated relative to their feeding habits. Rock bass are primarily crepuscular benthic feeders (taking Anisoptera nymphs and crayfish), and bluegill are diurnal generalized predators of chironomid larvae, Cladocera, and Trichoptera. In individuals of equivalent body size, the rock bass was found to have a high-density area of double cone concentration (up to 18 000 cones/mm2) in the temporodorsal region of the retina. This indicates that the main visual direction for prey detection is below the horizontal plane. In the bluegill the distribution of photoreceptors is more even and the average value over much of the retina is 6000–7000/mm2, with accordingly greater intercone spacing. This is probably appropriate for a fish feeding throughout the water column under good light conditions. The eye of the rock bass is 20% greater in rostrocaudal diameter than that of bluegill of equivalent size, implying greater light-gathering capacity. Moreover, individual cones in the rock bass are larger in surface area. These features, and a greater degree of neural summation (with resultant high visual sensitivity), have been regarded as adaptations for feeding under dim light. Differences in diet and feeding behavior in these two species thus have a morphological basis.

scholarly journals Morphological change and phenotypic plasticity in response to water velocity in three species of Centrarchidae

2015 ◽  
Vol 93 (11) ◽  
pp. 879-888 ◽  
Author(s):  
A.E. Istead ◽  
S. Yavno ◽  
M.G. Fox
Keyword(s):  
Phenotypic Plasticity ◽  
Water Flow ◽  
Morphological Changes ◽  
Lepomis Macrochirus ◽  
Lepomis Gibbosus ◽  
Rock Bass ◽  
Morphological Responses ◽  
Species Specific ◽  
Static Conditions ◽  
Response To Water

Morphological responses to flowing water have been documented in many fishes, but rarely reported in species with gibbose body types, despite their use of riffles in rivers and streams. In this study, we compared morphological responses to water flow in three gibbose centrarchids: bluegill (Lepomis macrochirus Rafinesque, 1819), pumpkinseed (Lepomis gibbosus (L., 1758)), and rock bass (Ambloplites rupestris (Rafinesque, 1817)). Flow-through plexiglass units, set to either a sustained flow or static conditions, were used to rear juveniles from each species for an 80-day period. All three species developed more streamlined body forms, longer and thinner caudal peduncles, and longer pectoral fins when reared in sustained current. Pumpkinseed exhibited the highest level of phenotypic plasticity in response to water flow, followed closely by bluegill; rock bass was the least plastic species. Rock bass developed longer predorsal and prepectoral lengths, which differ from the morphological changes observed in bluegill and pumpkinseed. The findings not only suggest that some gibbose fishes are capable of exhibiting strong phenotypic responses to water flow, but that many morphological changes are species specific, even within the same taxonomic family. Lastly, all three species developed shorter dorsal fin base lengths when reared under flowing condition, which differs from some previously documented work on fusiform fishes. The results of this study provide a better understanding of how morphology in three closely related species varies in response to environmental conditions.

Study of fish movements under constant conditions of light and darkness

1970 ◽  
Vol 48 (1) ◽  
pp. 109-118 ◽  
Author(s):  
N. N. Kapoor ◽  
H. Kleerekoper
Keyword(s):  
Rainbow Trout ◽  
Lepomis Gibbosus ◽  
Experimental Tank ◽  
Experimental Conditions ◽  
Left Handed ◽  
Ictalurus Nebulosus ◽  
Rock Bass ◽  
Definite Pattern ◽  
Locomotor Patterns ◽  
Ambloplites Rupestris

This paper deals with the locomotor movements of four fish species, Salmo gairdnerii irideus Gibbons, Ambloplites rupestris rupestris (Rafinesque), Ictalurus nebulosus nebulosus (Le Sueur), and Lepomis gibbosus (Linnaeus), and the locomotor patterns displayed by non-conditioned animals in constant conditions of light and darkness.The entries into the 16 sectors of the tank were uniformly distributed; there was no preference shown by the fish for any one sector of the experimental tank, regardless of the light condition.Most animals with the exception of the rock bass displayed a definite pattern of locomotor movements, consisting of a range of turning angles. Variations in this pattern were not significant from day to day under similar experimental conditions of light.Frequencies of right- and left-handed turns showed individual differences in a large number of bullhead and pumpkinseed, whereas there were no differences in rock bass. Thigmotaxis and vision might play a role in this turning behavior.Animals displayed a different angular pattern of locomotion under light and dark conditions. Rock bass and pumpkinseed showed a preference for short angle turns whereas rainbow trout made turns of longer angles. Bullhead showed no change in the magnitude of the angles of turn.

Observations on the biology of Ergasilus spp. (Cyclopoidea: Copepoda) infesting North American freshwater fishes

1969 ◽  
Vol 47 (3) ◽  
pp. 405-408 ◽  
Author(s):  
Shibru Tedla ◽  
C. H. Fernando
Keyword(s):  
Yellow Perch ◽  
Host Preference ◽  
Parasite Species ◽  
Perca Flavescens ◽  
Smallmouth Bass ◽  
Lepomis Gibbosus ◽  
Rock Bass ◽  
Egg Number ◽  
Ambloplites Rupestris ◽  
Immature Specimen

The gills of 118 yellow perch, Perca flavescens; 18 pumpkinseed, Lepomis gibbosus; 14 rock bass, Ambloplites rupestris; and 15 smallmouth bass, Micropterus dolomieui, were examined for Ergasilus spp. Ergasilus caeruleus was recovered for pumpkinseed and E. confusus from yellow perch. Rock bass and smallmouth bass were infested with E. centrarchidarum and one immature specimen of this species was recovered from a pumpkinseed. The host preference of each parasite species is discussed. A relationship between the egg number of copepods with more than one host and the degree of host preference is suggested.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

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