Space-Temporal Presence of the Cirripede Parasite Loxothylacus texanus in the Lagoon-Estuarine Subsystem of Alvarado, Veracruz, Mexico

The rhizocephalan Loxothylacus texanus, parasite of the crabs Callinectes sapidus and C. rathbunae, appears mainly in the Gulf of Mexico where important economic losses have been attributed to this parasite. The main objective of this study was to explain parasite-host relationship in time and space. A total of 756 organisms were collected, from which there were obtained 545 healthy crabs (72%), 32 feminized males (4.23%), 51 with virgin externa (6.74%), 31 with immature externa (4.1%) and 97 organisms with mature externa (12.8%). It was calculated a sexual proportion of the healthy organisms of 54.86% (299) for the males and 45.14% (246) for the females (sex ratio 1.2:1.0). For the parasitized organisms it was calculated a proportion of 50.24% (106 crabs) for the males and 49.76% (105 crabs) for the females (sex ratio 1.0:1.0). It can be concluded that L. texanus is persistent in time and space in the lagunar subsystem of Alvarado, Veracruz. Its prevalence is greater in dry seasons and in salinities higher than 8, but lower than 24. L. texanus is distributed in an isolated manner inside the lagoon, which allows that the zones with salinities other than 8-24 can serve as refuges to the megalopas and the early stages of C. rathbunae from this rhizocephalan. L. texanus is not selective in regard to the hosts sex. The degree of development of the externa affects the osmoregulatory capacity of the host on benefit of the parasite.