No abstract

The habitat requirements of early benthic stage juveniles of California spiny lobster Panulirus interruptus are known only from studies conducted near its northernmost geographic range, where environmental conditions differ markedly from those along the Pacific coast of the southern Baja California Peninsula (Mexico). We determined the natural habitat of this stage of P. interruptus in the central portion of their range from sampling the available dominant vegetated habitats included various seagrasses and macroalgae. Additionally, experiments on habitat selection by early benthic juvenile P. interruptus were performed under laboratory conditions to test natural substrate selection and whether selection of substrata is affected by odour signals. Despite the abundance of different macrophytes as habitat, 93% of the juvenile lobsters were found at the base of the blades of Phyllospadix spp. in the intertidal zone at 0 to 3 m. The highest juvenile densities were found in September at both sites. In laboratory experiments, juvenile lobsters preferred, in order of preference, Gelidium robustum, Phyllospadix, Plocamium pacificum, and holdfasts of the kelp Macrocystis pyrifera. A second laboratory experiment showed that these preferences were affected by odour signals. Results indicate that the ecology of juvenile P. interruptus off the coast of the Mexican Baja is similar to that observed off the coast of southern California.

We analyzed rocky reef benthic macroalgae on the western coast of the Baja California peninsula, Mexico. To describe the assemblages, we sampled two reefs that are geographically proximate but influenced by different oceanographic conditions, leading to potential differences in factors that could affect the macroalgal assemblage. Using analyses of similarities, we found significant differences between sites and seasons. Additionally, composition changed seasonally, but was not related to depth. Using SIMPER analysis, the species that defined the assemblages at “Arvin”, Tortugas Bay were Macrocystis pyrifera, Sargassum muticum and Plocamium cartilagineum; in contrast, the key components at “Queen” were Padina caulescens, Polysiphonia johnstonii var. concinna and Dictyota coriacea, showing how oceanographic conditions can influence the biogeographic pattern of macroalgal assemblages along the northwestern coast of Mexico.

Resumen.-Se analizó la condición nutricional y el desarrollo gonádico de juveniles y sub-adultos de langosta roja (Panulirus interruptus) en 2 sitios de la Península de Baja California cercanos geográficamente, pero con condiciones ambientales contrastantes, el más norteño con condiciones subtropicales y el sureño con condiciones semitempladas. Se estimaron el índice hepatosomático y el índice refractivo de la sangre, y se cuantificaron las proteínas, lípi dos y carbohidratos del hepatopáncreas en 62 langostas. Adicionalmente, se comparó el desarrollo gonádico de los organismos en ambos sitios. El índice hepatosomático y la cuantificación de lípidos mostraron que la condición nutricional de los organismos fue diferente en cada sitio. Se observó que los índices de condición nutricional son afectados por el de sarrollo gonádico debido al uso de reservas para la maduración de las gónadas. La condición nutricional y el desarroll o gonádico están fuertemente relacionados con las condiciones ambientales donde se encuentran las langostas, lo cual es información útil para el manejo de la pesquería de P. interruptus. Palabras clave: Langosta, Panulirus interruptus, reproducción, condición nutricional, Península de Baja CaliforniaAbstract.-The nutritional condition of juveniles and subadults of the California spiny lobster (Panulirus interruptus) from 2 sites along the west coast of the Baja California Peninsula, near each other but with contrasting environmental conditions were compared. The northern site presents subtropical environmental conditions and the southern has semi-temperate. The hepatosomatic and blood refractive indices and proteins, lipids, and carbohydrates from the hepa topancreas in 62 lobsters were assayed. Gonad development of the lobsters between the 2 sites was compared. The hepatosomatic index and lipids of the lobsters at each site were different. The nutritional condition indices are affected by gonad development tied to the reserves needed for maturation of the gonads. Nutritional condition and gonad development are strongly related to environmental conditions. This is key to efforts in spiny lobster fishery management.