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Heritable Melanism And Parasitic Infection Both Result In Black-Spotted Mosquitofish, Lisa Horth, David Gauthier, Wolfgang Vogelbein
Heritable Melanism And Parasitic Infection Both Result In Black-Spotted Mosquitofish, Lisa Horth, David Gauthier, Wolfgang Vogelbein
Biological Sciences Faculty Publications
Male Gamhusia holhrooki (Eastern Mosquitofish) express a heritable pigmentation polymorphism approximate to 99% of males are silver, and only approximate to 1% have a melanic, black-spotted pattern. Sex-linkage, an autosomal modifier, and temperature control the expression of this heritable melanism. In many teleosts, melanin also accumulates around the site of parasitic invasion. We have identified black-spot disease in wild mosquitofish from their native habitat. Here, we demonstrate convergence upon the black-pigmented phenotype through two means: 1) heritable melanism, and 2) melanic spotting on the silver genotype that results from infection with immature encysted trematodes. Females are silver and express greater …
Age, Growth, And Reproduction Of Tautog Tautoga Onitis (Labridae: Perciformes) From Coastal Waters Of Virginia, E. Brian Hostetter, Thomas A. Munroe
Age, Growth, And Reproduction Of Tautog Tautoga Onitis (Labridae: Perciformes) From Coastal Waters Of Virginia, E. Brian Hostetter, Thomas A. Munroe
Biological Sciences Faculty Publications
Tautog Tautoga onitis are gaining popularity in Virginia's coastal waters as a recreational and food fish. Adult tautog are seasonally abundant on inshore hard-bottom habitats (1-10 m) and inhabit offshore areas (10-75 m) year-round. Juveniles, especially newly-settled recruits, inhabit vegetated areas in shallow water (usually < 1 m). From March 1979 to July 1986, tautog were collected in lower Chesapeake Bay and nearby coastal waters to examine age, growth, and sexual maturation. Age estimates were determined from annular marks on opercle bones: 82% of the fish were age-10 or younger, 18% exceeded age-10, and 1% were age-20 or older. Marginal increment analysis revealed that annuli formed concurrent with a protracted spawning season (April-July). The von Bertalanffy growth equation, derived from back-calculated mean lengths-at-age, was l(t) = 742 [1-e-0.085 (t-1.816)]. Tautog are long-lived (25+ yr) and attain relatively large sizes (672 mm TL) slowly (K for sexes combined = 0.085). Growth rates of both sexes are similar, although males grow slightly faster (K = 0.090 vs. 0.085 for females). Maturity occurs at age-3 in both sexes. Growth rates for tautog from Virginia are similar to those reported nearly 25 years ago for tautog in Rhode Island. Growth rates for tautog are similar to those of other reef fishes, such as snappers and groupers. Habitat restriction, slow growth, great longevity, and increasing popularity by user groups may contribute to over-exploitation of this species in Virginia waters.