José Luis Bonilla-Gómez

Physiological and Biochemical Changes of Wild and Cultivated Juvenile Pink Shrimp Farfantepenaeus Duorarum (Crustacea: Penaeidae) During Molt Cycle

ABSTRACT Changes in metabolite levels in hemolymph and hepatopancreas were used as indicators of physiological status of juvenile wild and cultivated Farfantepenaeus duorarum (Burkenroad, 1939), during hyper-osmoregulatory conditions (salinity 22 ppt, 726 mOsm/kg). We analyzed the relationship between biochemical changes of wild and cultivated shrimp at different molt stages by measurement of osmotic capacity, hemocyanin, acylglycerides, cholesterol, glucose, glycogen and total protein. Biochemical analyses of hemolymph (blood) and hepatopancreas showed a decreasing trend in stages closer to molt and an increasing trend before intermolt. Osmotic capacity and blood proteins indicated a significant effect of the molt stage. Stages A, D1′ and D1′″ showed the greatest effect on the biochemical variables. Higher hemocyanin, cholesterol and glycogen concentrations were observed in wild shrimp than in cultivated shrimp. The effect of the molt cycle was associated with changes in cyclic ions and water balance that produced chemical changes in the hemolymph in both wild and cultivated.

GROWTH AND MORTALITY OF RED LIONFISH, PTEROIS VOLITANS (ACTINOPTERYGII: SCORPAENIFORMES: SCORPAENIDAE), IN THE PARQUE NACIONAL ARRECIFE ALACRANES, SOUTHERN GULF OF MEXICO, AS DETERMINED BY SIZE-FREQUENCY ANALYSIS

Background. Biological invasions represent a threat to the ecological stability of the ecosystem. Two lionfi sh species, the red lionfi sh and the devil fi refi sh—both tropical marine predators native to the Indo–Pacifi c—were introduced to the Atlantic Ocean. However, only one—the red lionfi sh, Pterois volitans (Linnaeus, 1758)—has reached the level of an invasive species so far. It is crucial to learn its biology and ecology to understand trends of its invasion and impacts on native fauna, and to determine ecological changes as the invasion progresses. This study reports the growth and mortality of P. volitans in coral reefs of the Parque Nacional Arrecife Alacranes, off the northern Yucatan Peninsula, Mexico, in Southern Gulf of Mexico. Materials and methods. Lobster diver fi shers participated in voluntary captures of lionfi sh during the lobster fi shing seasons of 2010–2012. In the laboratory, lionfi sh were taxonomically identifi ed, measured, and weighed. Their length–weight relation was determined according to the commonly used equation: W = aTL b . Fish total lengths were used to calculate the parameters of the von Bertalanffy growth function (VBGF) of lionfi sh based on the size-frequency analysis routine ELEFAN in the FiSAT II software. Results. A total of 776 lionfi sh (9.0 to 38.9 cm in total length, 7 to 874 g in total wet weight) were collected. The VBGF parameters estimated were L ∞ = 42 cm, K = 0.88 –1 , t 0 = –0.107 years. The total mortality instantaneous rate (Z) calculated by the total length converted catch curve was 2.06 year –1 . Conclusion. This study provides fi rst calculation of growth parameters and mortality of P. volitans in Southern Gulf of Mexico as determined by size-frequency analysis. Results contribute to the knowledge on the biology of P. volitans and to a better understanding of aspects of its biological invasion in the region.

Environmental Influences on the Abundance of Dominant Fishes in a Very Shallow Tropical Coastal Lagoon in Northwestern Yucatan Peninsula, Mexico

Spatial-seasonal patterns of six abundant fishes were analyzed in La Carbonera, a lagoon on the northwestern coast of the Yucatan peninsula, Mexico; between April 2009 and May 2010, via non-parametric multivariate analysis. The null hypothesis tested was that no differences existed in the overlapping of the abundance of fish species among the lagoon defined by types of habitats (channel, seagrass, mangrove and hypersaline), and by three climatic seasons (dry, rainy, and north winds). Significant differences were found in the environmental variables between climatic season and the types of habitat, except for the temperature and pH. Result of the multidimensional scaling suggests a significant difference in habitats with characteristics of channel and presence of mangrove. The redundancy analysis showed that depth and salinity were the best related to species abundance. Oxygen and temperature made an additional significant contribution to the canonical model, it was strongly related to the north winds season, due to the fact that the strong winds, which can last a week, increase the oxygen content of the water but decrease the temperature. Relative abundances were strongly associated with depth (dry; r=0.76), salinity (rainy; r=0.83) and oxygen (north winds; =-0.80). Results suggest that the different habitats are used as feeding zones; and that during the dry season, there was a overlapping in abundance of species. Thus, information proposed protection strategies in this season to contribute to fish biodiversity conservation in a valuable area of Yucatan Peninsula.