Carlos González-Salas

High serotonin levels due to the presence of the acanthocephalan Hexaglandula corynosoma could promote changes in behavior of the fiddler crab Uca spinicarpa.

Between February and June 2010, 113 fiddler crabs Uca spinicarpa were collected from the Chuburna lagoon system on the northern coast of the Yucatan Peninsula, México. Of the 68 crabs gathered outside their burrows, 13 were infected with 25 cystacanths of Hexaglandula corynosoma (intensity of infection from 1 to 5) and the remaining 55 crabs were uninfected. The other 45 crabs were found inside their burrows and only one was found infected with 1 cystacanth of H. corynosoma. Serotonin (5-HT) levels were higher in the group of crabs infected with H. corynosoma in contrast to the group of uninfected crabs and the group of those infected with other parasites. A redundancy analysis corroborated a positive relationship between 5-HT and the intensity of infection with H. corynosoma. In contrast, dopamine levels remained similar among different groups of crabs.

Metazoan parasite infracommunities of Mycteroperca bonaci (Poey, 1960) (Pisces: Epinephelidae) in reef and coastal environments off the coast of Yucatán, México

Abstract The black grouper Mycteroperca bonaci is a commercially important fish off the coast of Yucatan, Mexico. To investigate possible differences between parasite communities in two different environments, 60 fish were collected from two areas during 2010 and 2011 and examined for parasites. The fish were classified into two age groups, in each of which the parameters of parasitic infection - prevalence, abundance and intensity - were determined. Parasite faunas were further described at the infracommunity level. Using both univariate (PERMANOVA) and multivariate statistical methods, the values of richness, abundance, diversity and Brillouin evenness as well as the Index values of Bray-Curtis and Jaccard for similarity were calculated and compared. The results of these tests and of CAP discriminant analyses at the two sites showed the existence of two distinct parasite communities. The parasite taxa mainly responsible for the differences were the digeneans Dollfustrema sp., Prosorhynchus spp., Lepidapedoides epinepheli and Hamacreadium mutabile, and the nematode Philometra salgadoi. The potential for some of these parasites to be used as biological tags for stock identification of M. bonaci is discussed.

Age-specific environmental differences on the otolith shape of the bastard grunt ( Pomadasys incisus ) in the north-western Mediterranean

The effects of sex, age, and environment on the shape of the bastard grunt (Pomadasys incisus) otoliths from the north-western Mediterranean were investigated. Specimens of this species were collected from two separate sampling areas in the north-western Mediterranean with different thermal regimes. Sex, growth rates, and age of P. incisus were determined by using gonad histology techniques, biometric analyses, and otolith microstructure analyses, respectively. The shape was described using normalized Elliptic Fourier descriptors (EFDs), and studied by means of multivariate statistics as predictive variables with age-specific discriminant analyses. There were no consistent differences found between sexes, but otolith shapes varied significantly between environments within different age classes. Total classification success varied between 87.3% and 89.2% between environments for the different age classes and provided a phenotypic basis for P. incisus population separation within an environmental gradient in determining its otolith shape. In addition, significant differences were observed between sampling areas in von Bertalanffy’s growth parameters, as well as in the fish length-weight (LWR) and fish length-otolith radius (TL-Ro) relationships. Data was discussed considering that the physical habitat variability could underlie a marked change in otolith shape during the animals’ growth. In this matter, we discussed the relative importance of both ontogenetic and environmental conditions (such as water temperature) on otolith shape.

Octopus maya parasites off the Yucatán Peninsula, Mexico. II. Salivary gland damage by cestodes

The red octopus Octopus maya Voss et Solís-Ramírez, 1966 is an endemic species and one of the most important fishery resources of the Yucatán Peninsula, Mexico. Due to its economic importance and the fact that in recent years interest in farming this species has increased, several initiatives have been implemented to study its biology and requirements for cultivation. Parasites represent an important component of the biology of the red octopus, as they can have an impact on both wild and cultivated populations. A total of 44 O. maya specimens were sampled from the fishing ports of Ría Lagartos and Dzilam de Bravo, Yucatán; specimens were measured and subsequently subjected to histological analysis of the buccal masses where cestode larvae (Prochristianella sp.) were found in the anterior salivary glands. Results of a chi-squared test showed that specimen size class and infestation levels (parasite abundance) were significantly correlated, with parasite damage levels more pronounced in larger animals. The damage caused to the anterior salivary glands by this parasite could have serious implications for feeding and reproductive success of O. maya.