Evaluating hybridization potential between Penaeus setiferus and Penaeus vannamei through natural mating, artificial insemination and in vitro fertilization

Abstract

The culture of Pacific white shrimp Penaeus vannamei (PVA) within the geographical range of Atlantic white shrimp P. setiferus (PSE) has prompted concern regarding potential ecological risks. The present study evaluates the potential for spontaneous hybridization between these closely related litopenaeid species. Prezygotic barriers to hybridization were evaluated utilizing quantitative analysis of behavioral interactions associated with mating, artificial insemination, and a novel in vitro fertilization technique. There was a significant decrease in the number of interspecific behavioral interactions ( P < 0.005). In total, 15 ♀ PSE × ♂PSE and 11 ♀PVA × ♂PVA matings were achieved. No spontaneous matings were observed between species. In artificial insemination trials, 60% of the intraspecific inseminations were fertile with mean fertilization rates of 9.21 ± 3.83% for PSE and 11.6 ± 5.2% for PVA. No interspecific crosses were fertile. This study documents in vitro fertilization for the first time in two litopenaeid species. In vitro fertilization was achieved by upwelling a concentrated sperm suspension under a spawning female. Three levels of negative controls were used to eliminate the possibility of contamination. Fertilization was achieved in 13 of 14 intraspecific trials with mean fertilization rates of 2.48 ± 0.57% for PSE and 3.88 ± 1.34% for PVA. No interspecific crosses were fertile. Based on the low levels of behavioral interaction during interspecific crosses, the lack of natural interspecific matings, and absence of fertilization in interspecific crosses for both artificial inseminations and in vitro fertilizations, the potential for hybridization between P. setiferus and P. vannamei appears to be negligible.