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Stream-finding behavior of adult sea lamprey (Petromyzon marinus), an anadromous fish that relies on pheromones to locate spawning streams, was documented in the vicinity of an important spawning river in the Great Lakes. Untreated and anosmic migrating sea lampreys were implanted with acoustic transmitters and then released outside the Ocqueoc River. Lampreys swam only at night and then actively. When outside of the river plume, lampreys pursued relatively straight bearings parallel to the shoreline while making frequent vertical excursions. In contrast, when within the plume, lampreys made large turns and exhibited a weak bias towards the river mouth, which one-third of them entered. The behavior of anosmic lampreys resembled that of untreated lampreys outside of the plume, except they pursued a more northerly compass bearing. To locate streams, sea lampreys appear to employ a three-phase odor-mediated strategy that involves an initial search along shorelines while casting vertically, followed by river-water-induced turning that brings them close to the river's mouth, which they then enter using rheotaxis. This novel strategy differs from that of salmonids and appears to offer this poor swimmer adaptive flexibility and suggests ways that pheromonal odors might be used to manage this invasive species. Nous avons etudie le comportement de recherche des cours d'eau chez des grandes lamproies marines (Petromyzon marinus) adultes, des poissons anadromes qui utilisent les pheromones pour trouver leurs cours d'eau de fraie, dans les environs d'une importante riviere de reproduction dans les Grands Lacs. Nous avons implante; des eemetteurs acoustiques a des grandes lamproies marines migratrices, certaines non traiteees et d'autres anosmiques, et les avons liberees a l'exterieur de la riviere Ocqueoc. Les lamproies nagent seulement la nuit, mais de facjon active. A l'exteerieur du panache de la riviere, les lamproies suivent un cours relativement rectiligne parallele a la berge, tout en faisant de frequentes excursions verticales. En revanche, une fois dans le panache, les lamproies font de grands virages et montrent une faible preference pour l'embouche de la riviere dans laquelle un tiers d'entre elles peenetrent. Le comportement des lamproies anosmiques hors du panache ressemble a celui des lamproies non traitees, excepte; qu'elles poursuivent un cap compas plus vers le nord. Pour localiser les cours d'eau, les lamproies semblent utiliser une strategie en trois phases basee sur les odeurs qui implique une recherche initiale le long de la rive avec des excursions verticales, suivie d'un virage cause par l'eau de la riviere qui les ame;ne pres de l'embouchure du cours d'eau, dans lequel elles penetrent ensuite par rheotaxie. Cette strategie ineedite differe de celle des salmonidees et semble fournir une flexibilite; adaptative a ce mauvais nageur; elle permet d'imaginer des facons d'utiliser les odeurs des pheromones dans la gestion de cette espeece envahissante. [Traduit par la Redaction], Introduction Although it is commonly thought that most, if not all, species of anadromous fishes locate spawning rivers from oceans and large lakes using olfactory cues, the orientation mechanisms they [...]

There is an urgent need to block the passage of carp and other invasive fishes through navigational locks in large rivers. Although the broadband sound of an outboard motor has been shown to strongly repel three species of carp in laboratory flumes and to a lesser extent inside of a lock chamber, it has not yet been tested to determineif it can stop carp from entering a lock. To test this possibility, we attached speakers to lock gates and played the sound of an outboard motor while measuring its efficacy by tracking free-ranging transplanted tagged common carp in its vicinity. Eight groups of 20 carp were tested while the sound system was turned on and off for 2 week periods. When the sound system was on, these carp spent approximately one-third less time in front of the lock gates than when it was off; however, when analyzed by a GLMM this effect was shown to be no greater than the effects of river discharge or temperature. Additionally, lock entrance rates were lower, albeit non-significantly, when the sound was off. A number of factors may have contributed to the limited efficacy of this deterrent system including the sound itself. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.02.032 Byline: Christopher W. Appelt, Peter W. Sorensen Abstract: Although it is established that many species of fish release hormonally derived sex pheromones in their urine, whether these cues are unspecialized metabolic by-products or specialized communicatory signals is not known. Here, we addressed this question in the goldfish, Carassius auratus (a leading model of hormonal sex pheromone function) by conducting two experiments. We first monitored urine release by sexually receptive females that were placed with a sexually active male, an inactive male, another female, or no other fish. Sexual receptivity was induced using prostaglandin F.sub.2[alpha], a hormone also known to evoke release of 15-keto prostaglandin F.sub.2[alpha] (15K-PGF.sub.2[alpha]), a potent urinary pheromone. We found that sexually receptive females increased the frequency with which they urinated when placed with males (regardless of male sexual activity) but not females. Furthermore, females showed a strong tendency to urinate when rising into spawning substrate, suggesting they might be using urine as an attractive lure. This hypothesis was confirmed by a second experiment, which found that 15K-PGF.sub.2[alpha] attracted males to specific locations. We conclude that goldfish, and likely many other fish, control the release of urinary prostaglandin pheromones to advertise their condition and location, perhaps exemplifying an early step in the evolution of a chemical communication system. Author Affiliation: Department of Fisheries, Wildlife & Conservation Biology, University of Minnesota, U.S.A. Article History: Received 13 November 2006; Revised 10 January 2007; Accepted 28 February 2007 Article Note: (miscellaneous) MS. number: A10622

The structural determination of sulfated steroid derivatives, which hold considerable promise for applications in an environment friendly sea lamprey control program, is described.

Abstract: Pheromone-baited traps have proven highly effective for managing insect pests by selectively removing reproductively active adults prior to mating. Here, we report a field test of two pheromones produced [...]