effect of different photoperiodic regimes was evaluated on growth performance and survival rate of the beluga ( huso huso ) prelarvae and larvae. newly hatched prelarvae were stored in 5 round fiberglass 500‑l tank with different photoperiod (24l:00d, 18l:06d, 12l:12d, 06l:18 d, 00l:24d) till 50 days post hatch with three replicates. light intensity was 200 lux during the experiment. feeding wa...

Paenibacillus larvae is the etiological agent of American foulbrood (AFB) in honeybees. Recently, different genotypes of P. larvae (ERIC I to ERIC IV) were defined, and it was shown that these genotypes differ inter alia in their virulence on the larval level. On the colony level, bees mitigate AFB through the hygienic behavior of nurse bees. Therefore, we investigated how the hygienic behavior...

Pectoral fins are one of the major features of locomotor design in ray-finned fishes and exhibit a well-documented phylogenetic transition from basal to derived clades. In percomorph fishes, the pectoral fins are often used to generate propulsive force via oscillatory movements, and pectoral fin propulsion in this relatively derived clade has been analyzed extensively. However, in the plesiomor...

Water projects designed to extract fresh water for local urban, industrial and agricultural use throughout rivers and estuaries worldwide have contributed to the fragmentation and degradation of suitable habitat for native fishes. The number of water diversions located throughout the Sacramento-San Joaquin watershed in California's Central Valley exceeds 3300, and the majority of these are unsc...

Sturgeons are among the most CO2 tolerant of fishes investigated to date. However, the basis of this exceptional CO2 tolerance is unknown. Here, white sturgeon, Acipenser transmontanus, were exposed to elevated CO2 to investigate the mechanisms associated with short-term hypercarbia tolerance. During exposure to 1.5 kPa Pco2, transient blood pH [extracellular pH (pHe)] depression was compensate...

While the current expansion of conservation genetics enables to address more efficiently the management of threatened species, alternative methods for genetic relatedness data analysis in polyploid species are necessary. Within this framework, we present a standardized and simple protocol specifically designed for polyploid species that can facilitate management of genetic diversity, as exempli...

In this essay, three lines of evidence are developed that sturgeons in the Chesapeake Bay and elsewhere are unusually sensitive to hypoxic conditions: 1. In comparison to other fishes, sturgeons have a limited behavioral and physiological capacity to respond to hypoxia. Basal metabolism, growth, feeding rate, and survival are sensitive to changes in oxygen level, which may indicate a relatively...

EFFECTS OF HYDRAULIC DREDGING AND VESSEL OPERATION ON ATLANTIC STURGEON BEHAVIOR IN A LARGE COASTAL RIVER Michael R. Barber, B.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biology at Virginia Commonwealth University. Virginia Commonwealth University, 2017. Major Advisor: Dr. Greg Garman, Director of Rice Rivers Center, Center for Enviro...

Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super c...