Length-weight relationships of 33 cryptic reef fishes from the southwestern Gulf of California were estimated. The most common families were Gobiidae (seven species), Labrisomidae (four), Pomacentridae (three), and Tripterygiidae (three). These are the first length-weight parameters reported for 32 of these species. Specimens were sampled during a comparative ecological study of community structure of fish assemblages associated with coral heads, rocky walls, and artificial reefs in Bahı´a de La Paz, Baja California Sur. The b values varied between 2.63 and 3.61. New maximum length records for five of the species were established in the study.

RESUMEN. Para conocer y caracterizar la comunidad bentónica de la Laguna Guerrero Negro, se realizaron seis muestreos mensuales en 10 estaciones de julio a diciembre 2012. Los muestreos se realizaron mediante buceo autónomo en cuadrantes de 0,50 m 2 entre 5 y 12 m de profundidad, durante los períodos de sicigia. La información fue analizada mediante indicadores ecológicos y análisis estadísticos multivariados. Los resultados muestran que la comunidad bentónica marina está representada por 229 especies correspondientes a 11 filos, siendo los moluscos el grupo que presentó mayor riqueza específica (95 especies), y los artrópodos el de mayor abundancia (7543 individuos). Los indicadores ecológicos denotaron patrones similares en el dominio del tiempo con excepción de julio para el indicador de riqueza (S) en cuyo caso el valor fue más bajo (88) que el resto de los meses (S = 105); y alta heterogeneidad en el dominio espacial, encontrando diferencias estadísticas significativas en los valores de los indicadores ecológicos entre estaciones de muestreo. Se identificaron dos ensambles (grupos A y B) mediante un análisis de escalamiento multidimensional. El grupo A integrado por las estaciones asociadas a los canales secundarios de la laguna, con menor resistencia a la corriente y menor influencia oceánica, en cuyo caso los indicadores ecológicos denotaron que éstas son mayormente ricas y diversas que el resto; mientras que el grupo B está compuesto por las estaciones ubicadas en el canal principal de la laguna, con corrientes más dinámicas y con mayor influencia del océano, sugieren una estratificación espacial permanente en el tiempo, principalmente influenciada por los patrones dinámicos de corrientes de la laguna. Palabras clave: bentos, ecología de comunidades, laguna costera, Baja California. Biocenosis of benthic community in Guerrero Negro Lagoon, Baja CaliforniaSur, Mexico: spatio-temporal characterization ABSTRACT. In order to know and characterize the benthic marine community at Guerrero Negro Lagoon, Baja California Sur, Mexico, a monitoring during six months were conducted, sampling 10 stations every month from July to December of 2012. Collected samples were taken with 0,50 m 2 quadrants by scuba between 5 and 12 m in depth during periods of syzygy tides. All information was analyzed by ecological indicators and multivariate statistical analyzes. Our results showed that marine benthic community is represented by 229 species corresponding to 11 phylum, highest species richness was represented by mollusks (95 species), and the most abundant was arthropods group (7543 individuals). Ecological indicators denoted similar patterns in the time domain except for July, with the lowest value for richness (S = 88) compared with ̅ = 105 for the other months; and high heterogeneity in the spatial domain, finding statistical differences in the ecological indicators values between sampling stations. Considering spatial high heterogeneity, we performed a multidimensional scaling analysis finding two assemblages (groups A ...

ABSTRACT. Information concerning Neastacilla californica is currently scarce. In fact, its distribution range is not yet well defined; this species is currently reported from Point Conception to Point Loma along the California coast, USA, and also in the Gulf of California, Mexico. In this note, we present a new zoogeographical record of N. californica with information derived from a sample of taken in July 2012 during a monitoring expedition in the area inside of the Guerrero Negro Lagoon, at Peninsula de Baja California, Mexico, at 4.3 latitudinal degrees from the southernmost point reported on the Pacific coast. Additionally, we present a comparative summary of the main diagnostic features of this species and a series of photographs that allow observing characteristics of N. californica, contributing to the knowledge of the species.