Spawning pheromone

Carolsfeld, J., Scott, A. P., and Sherwood, N. M. (1997b). Pheromone-induced spawning of Pacific herring. 2. Plasma steroids distinctive to fish responsive to spawning pheromone. Hormones and Behavior 31,269-276. 

Female Goldfish release a spawning pheromone in their urine. They release urine in pulses every 2-4 min. These pulses can be made visible by a blue dye in the urine (Appelt and Sorensen 1999). 

Pickett JA, Griffiths DC (1980) Composition of aphid alarm pheromones. J Chem Ecol 6 349-360 Ram JL, Mueller CT, Beckmann M, Hardege JD (1999) The spawning pheromone cysteine-glutathione disulfide ( Nereithione ) arouses a multicomponent nuptial behaviour and electro-... 

Sorensen, P W., Stacey, N.E. Naidu, P. 1986. Release of spawning pheromone(s) by naturally ovulated and prostaglandin-injected, nonovulated female goldfish. In Chemical Signals in Vertebrates 4 (Ed. by D. Duvall, D. Muller-Schwarze R.M. Silverstein), pp 149-154. New York Plenum Press. 

RELEASE OF SPAWNING PHEROMONE (S) BY NATURALLY-OVULATED AND PROSTAGLANDIN-INJECTED, NONOVULATED FEMALE GOLDFISH... 

Hong, W.S., Chen, S.X., and Zhang, Q.Y. et al. (2006). Sex organ extracts and artihcial hormonal compounds as sex pheromones to attract broodfish and to induce spawning of Chinese black sleeper (Bostrichthys sinensis Lacepede). Aquaculture Research 37, 529-534. 

Support for the pheromone hypothesis has come from preference tests in Atlantic salmon parr and experiments with sea lampreys migrating upstream to spawn. 

All male fish pheromones are steroidal (Sorensen and Stacey, 1990). Many male fish release chemicals that attract females, stimulate them to spawn, and inhibit their aggression. As early as 1982, Liley compiled a long list of examples testes, as in goldfish (Stacey and Hourston, 1982), urogenital fluid, glands on the caudal peduncle (an anal fin appendage), mucus and urine, can be sources of male pheromones. 

In various fish species, sexually mature females that are ready to spawn emit chemicals to attract a male and stimulate him to court, release sperm into the water, be more active, build a nest, or assume the courtship coloration. We know more examples than for male pheromones (Liley, 1982). Sources of female pheromones can be ovarian fluid, eggs, mucus, urine, or skin. 

The olfactory system of the male is extremely sensitive to 17,20jSP. The fish respond to a concentration of 5 x 10 ° mol/1. This amount(3 x 10 molecules) is released by a 90 mm female fish into 1 liter water. The females are also very sensitive to 17,20/3P. It may stimulate ovulation. Of 47 vitellogenic females 13 ovulated when 17,20/3P was added to the water, while only 1 of 43 did so in untreated water (Dulka etal, 1987). Both sexes probably release 17,20/3P. Ecologically, this bisexual pheromone is thought to synchronize milt production with ovulation and thus coordinate spawning in local populations (Dulka etal, 1987 Sorensen and Stacey, 1990). 

Under certain conditions, ovulation and plasma gonadotropin levels can be stimulated by ovarian fluid from other ovulated females. The African catfish, Clariasgaricpinus, is an example. It lives in muddy water and spawns at night, conditions expected to favor pheromone commimication. Moreover, this species is a seasonal breeder, spawning after rainfall. The sudden mass spawning requires synchronization. Water from males or ovulated females, and also ovarian fluid of ovulated females, experimentally induced ovulation in 67% of females. Plasma gonadotropin was also increased by these treatments (Resink etal., 1989c). 

Chemical lures, based on feeding stimuli, are now on the market as odor-impregnated artificial bait. They are specific for certain predatoiy fish and are extremely effective (Schisler and Bergesen, 1996). Efforts to imderstand improving of feeding attractants and stimulants for economically soimd mariculture started early (Bardach and Villars, 1974). Another obvious application of fish odors is the use of waterborne male and female pheromones to improve spawning in fish in aquaculture. 

De Fraipont, M. and Sorensen, P. W. (1993). Exposure to the pheromone 17cc,20 /3-dihydroxy-4-pregnen-3-one enhances the behavioral spawning success, sperm production and sperm motility of male golddsh. Animal Behaviour 46,245-256. 

Dulka, J. G., Stacey, N. E., Sorensen, P. W. and van der Kraak, G. J. (1987). A steroid sex pheromone synchronizes male-female spawning readiness in goldfish. Nature 325, 251-253. 

Hardege, J.D. and Bentley, M.G., Spawning synchrony in Arenicola marina evidence for sex pheromonal control, Proc. R. Soc. Lond. B Biol., 264, 1041, 1997. 

Reproductive priming pheromones. Many species of fish are external fertilizers, and they spawn only a few times, which means that it is essential that male and female gamete outputs coincide. There is strong evidence that synchronization is mediated by sensory cues, including pheromones, most of which appear to be hormonally derived. 

The African catfish (Clarias gariepinus) is native to subtropical Africa but is now cultured across the planet. Males and females of this species spawn as pairs in flooded vegetation in turbid waters and appear to use pheromones to locate and identify each other. 

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