No abstract

Four behavioral experiments conducted in both the laboratory and the field provide evidence that adult sea lamprey (Petromyzon marinus) select spawning rivers based on the odor of larvae that they contain and that bile acids released by the larvae are part of this pheromonal odor. First, when tested in a recirculating maze, migratory adult lamprey spent more time in water scented with larvae. However, when fully mature, adults lost their responsiveness to larvae and preferred instead the odor of mature individuals. Second, when tested in a flowing stream, migratory adults swam upstream more actively when the water was scented with larvae. Third, when migratory adults were tested in a laboratory maze containing still water, they exhibited enhanced swimming activity in the presence of a 0.1 nM concentration of the two unique bile acids released by larvae and detected by adult lamprey. Fourth, when adults were exposed to this bile acid mixture within flowing waters, they actively swam into it. Taken together, these data suggest that adult lamprey use a bile acid based larval pheromone to help them locate spawning rivers and that responsiveness to this cue is influenced by current flow, maturity, and time of day. Although the precise identity and function of the larval pheromone remain to be fully elucidated, we believe that this cue will ultimately prove useful as an attractant in sea lamprey control.

No abstract

1992. [nfluence of fat content on uptake and depuration sf the sff-flavor 2-methylisobsrneol by channel catfish (bctalurus punctatus). Can. J. Fish. Aquat. Sci. 49: 2486-241 1.Channel catfish (Icealurus punstatus) sf different tissue fat contents (0.5-1 1 .O%) were held in water containing approximately 0.5 pg/L of the sff-flavor compound 2-methylissborneol (MlB) for various times. A new analytical method was developed to quantify tissue burdens of MlB. Fish showed significant bioeoncentration of MIB after 2 k and equilibrium by 24 h. The fatter fish (>2.5% muscle fat) accumulated nearly three times more MlB than lean fish (<2%j. Purging fish in MlB-free water indicated that leaner fish depurate faster (8 h) than fatter fish (48 h). Fat content had more influence in determining the time for return ts acceptable flavor than initial MIB concentration. Managing catfish production ts harvest leaner fish could minimize the impact of off-flavor on fish producers.Des barksues de riviPre (Ictalerrus punctatus) presentant diffbrentes teneurs tissulaires en graisses (de 0,s 2 11,0%) snt ete detenues dans de l'eau contentant environ 0,s pglL du compose 2-m6thylssborn&1I (MlB) generant une saveur desagreable pendant differentes pkrisdes. Une nouvelle methsde analytique a 6t6 mise au point pour quantifier la charge tissulaire en MIB. On a not6 chez les psisssns une biocowcentratisn significative de MIB aprPs 2 k et un kquilibre 21 24 h. Les p~issons plus gras (graisse musculaire > 2'5%) ont accumul6 pr6s de trois fois plus de MIB que les poissons maigres (< 2%). La purge des poissons dans de l'eau ne contenant pas de MIB a Indiquk que les poissons plus maigres detoxifient plus rapidement (8 k) que les psisssns plus gras (48 h). La teneur en graisses a eu plus d'influence pour detern-liner le temps requis jusqu'au retsur 2 une saveur acceptable que la concentration de MIB initiale. La gestisn de la production de Ia barbue de riviere avec capture des poissons plus maigres seulement pourrait minimiser I'impact de la saveur di2sagr6able sur les prsducteurs de poisssn.

ABSTRACT. A lexicon of terms to describe desirable as well as undesirable flavors in peanuts has been developed. The lexicon and an intensity rating scale was developed by a 13 member panel of flavor and peanut specialists representing industry and the USDA‐Agricultural Research Service. This system is intended to provide definitive, common terminology for use in communicating differences in peanut flavor variables among all phases of peanut research and industry.

The behavior of sham-operated and anosmic Atlantic salmon, Salmo salar, was studied in a fjord system with close reference to the fine-scale hydrographic features. Control fish made small-amplitude vertical movements, with sudden large-amplitude excursions. The anosmic fish made large continuous searches up and down in the water column, descended below the sill depth of the fjord, and followed the bottom contours. None of these three behaviors was seen in the control fish. The trauma caused by the surgical incision did not prevent the fish from active swimming, and a fish with unilateral sectioning of the olfactory nerve returned to the river of release. Activity of single olfactory bulb neurons was recorded during stimulation of salmon olfactory epithelium with water samples taken from different depths of the fjord. These water samples had been taken from regions that showed layering and to which migrating salmon demonstrated behavioral preferences in ultrasonic tracking experiments. Ninety percent of responding neurons showed differencial responses to the water samples, indicating the capacity of the olfactory system to discriminate among stratified water layers found in the ocean. We conclude that olfactory discrimination of fine-scale hydrographic features may provide a necessary reference system for successful orientation in nearshore regions by salmon.

No abstract

Daily movements of 17 carp bearing ultrasonic transmitters were monitored during autumn and winter of 1974-1975 and 1975-1976. In each year these fish joined concentrations of carp in two areas of Lake Mendota in late autumn before freeze-up. Instrumented carp arrived at these two areas with relative synchrony from different parts of the lake. Commercial fishermen, advised of these locations, harvested 46,400 kg of fish. The use of carp bearing ultrasonic transmitters to locate large concentrations could be useful as both a commercial fishing and management technique. Large concentrations of carp (Cyprinus carpio L.) reportedly form in deeper water during winter (McCrimmon 1968; Strand and Scidmore 1969). In 1974 we began instrumenting carp with ultrasonic transmitters and tracking them to determine if carp form large schools and, if so, their locations.The program was designed to evaluate the usefulness of ultrasonic tracking as a technique in the harvest and control of underutilized, non-gamefish species such as carp, bigmouth buffalo (Ictiobus cyprinellus Valenciennes) and freshwater drum (Aplodinotus grunniens Rafinesque). Our hypothesis was that a few instrumented fish would join major aggregations in the lake. Such fish would then reveal the areas to be fished for the most efficient harvest.