ABSTRACT
A taxonomic study of diatoms was carried out in a tropical coastal lagoon. Material for this study consists of water samples obtained from February-March 1992 to November-December 2000. Qualitative and quantitative analyses showed the presence of 373 taxa of which the families Bacillariaceae (67 species) and Chaetocerotaceae (37 species) were the most abundant groups. The species Skeletonema costatum, Chaetoceros curvisetus, Coscinodiscus radiatus var. radiatus, Ditylum brightwellii, Thalassiosira eccentrica and Entomoneis alata were found associated with moderate water quality and forming blooms. In addition, a regional comparison between Mexico and South America of the identified species is given. For practical handling, indicative values obtained from their ecological composition are incorporated as well as a code of the floristic list. A checklist of the species and their occurrence are given.
ABSTRACT
Reproduction, diet and fishery of Octopus (Octopus) hubbsorum (Mollusca: Cephalopoda) in the coast of Oaxaca, Mexico. The octopus Octopus hubbsorum (Berry 1953) ranges widely and is important for the artisanal fishery in Puerto Angel, Oaxaca, Mexico. Samples were taken approximately at every two weeks from January 2002 to November 2003. All organisms were measured for dorsal mantle length (DLM) and total weight; sex and maturity gonadic stage were registered. For the stomach content analysis, frequency of occurrence and emptying indexes were used. The 352 organisms caught ranged from 4 to 18 cm in DLM; the sex ratio was different from 1 (X² = 24.2, p<0.05) throughout the year. The maximum values of the GSI appeared in May (4.1917 for females; 1.2675 in males). LDM for first sexual maturity (LDM50%) was 16 cm (females) and 14 cm (males). Octopus hubbsorum moves from deep waters to the coast, probably in search of better conditions, and lays masses of eggs on rocky substrata. They are fished from March to October, with higher intensity in April and May. Fishing effort was related to the oceanographic characteristics and the atmospheric conditions of the area. From April to September the CPUE monthly mean was 20-10 kg/divers/day. Using the CPUE and environmental condition relationship, the estimated adequate superficial temperature for fishing is 29.5 °C. Rev. Biol. Trop. 57 (1-2): 63-78. Epub 2009 June 30.
Se analizan algunos aspectos de la biología y pesquería de Octopus hubbsorum capturado por pesca artesanal en Puerto Ángel, Oaxaca, México. Las muestras se obtuvieron de enero 2002 a noviembre 2003 con una periodicidad quincenal. A cada uno de los organismos se les registró la longitud dorsal del manto (LDM), peso total, sexo y estado de madurez gonádica. Asímismo se obtuvo el Índice Gonadosomático (IGS). Para el análisis del contenido estomacal se utilizaron los índices de frecuencia de presencia y vaciado. Se analizaron 352 organismos, con un intervalo de tallas de 4 a 19 cm LDM; la proporción de sexos fue diferente de 1 (.2= 24.2, p<0.05) todo el año. Los valores máximos del IGS se presentaron en mayo (4.1917 hembras; 1.2675 machos). La LDM de primera madurez sexual para las hembras es de 16 cm (machos 14 cm). Octopus hubbsorum viaja a la costa con el fin de colocar las masas de huevos sobre sustratos rocosos y probablemente en busca de condiciones más adecuadas que a mayores profundidades. La pesca se realiza todo el año con un incremento en las capturas de marzo a octubre, con mayor intensidad en abril y mayo. El esfuerzo de pesca se encuentra relacionado con las características oceanográficas y las condiciones atmosféricas de la zona. De abril a septiembre la captura por unidad de esfuerzo (CPUE) promedio mensual varió entre 10 y 20 kg/buzo/día. A partir de la relación entre la CPUE y las variables ambientales, se estimó una temperatura superficial del mar (TSM) óptima, la cual es de 29.5 °C para la captura de esta especie.