Reproductive Phenology of Pterocladiella capillacea (Rhodophyta: Gelidiales) from Southern Baja California, Mexico

The abundance of vegetative and reproductive fronds of Pterocladiella capillacea (Gelidiaceae) from an intertidal population at Lobos Point, on the Pacific coast of southern Baja California, Mexico, was measured bimonthly between March 1998 and January 1999. Fronds with tetrasporic sori occurred throughout the year, although in low percentages with respect to the total amount of fronds: monthly means ranged between 0.5% (May) and 6.0% (July). Fronds with cystocarps and fronds with spermatangia were found only in January, with even lower percentages: 0.15% and 0.10%, respectively. The overall predominance of reproductive tetrasporophytic fronds over reproductive gametophytic fronds is common in natural populations of the Gelidiaceae. Reproductive phenology, however, varies widely within this family, even within the same species, as is the case for P. capillacea. Little is known about factors affecting the reproductive phenology of this cosmopolitan alga; field and laboratory studies are needed to provide a reliable predictive framework

Main diatom taxa in the natural diet of juvenile Haliotis fulgens and H. corrugata (Mollusca: Gastropoda) in Bahía Tortugas and Bahía Asunción, B.C.S., México

To determine the main diatom taxa found in the natural diet of Haliotis fulgens Philippi (green abalone) and H. corrugata Wood (pink abalone) juvenile specimens and loose rocks were collected from different depths at two sites in Bahía Tortugas and Bahía Asunción, Baja California Sur. Overall 113 benthic diatom species were identified, and 98 taxa were recorded in the gut contents of both abalone species. Out of these 32 were not observed in the surrounding flora. Most diatom taxa were epiphytic forms, including the abundant taxa found in the gut contents of young abalone: Berkeleya fennica, Cocconeis speciosa, Cocconeis costata var. pacifica, Gomphonemopsis pseudexigua, Grammatophora marina, Navicula parva, Tabularia investiens, and Thalassionema nitzschioides. This somewhat re-flected the structure of the diatom assemblages in the rocky habitat: few abundant taxa and many rare or uncommon ones, with heterogeneous values of diversity (H') that ranged between 1.1 and 4.2 in the gut contents and from 2.83 to 3.91 in the surrounding flora. New records for the area include Cocconeis pseudomarginata, C. maxima (common), Licmosoma sp., Ardissonia formosa (rare), and the colonial form Berkeleya fennica (abundant), all found within the gut contents of abalone. The actual and potential diet of young abalone on the coast of Baja California Sur is extended to 235 taxa. The abundant taxa occurred frequently in clumps of numerous individuals in the gut contents, often still attached to algal tissue. The results of this investigation suggest that the importance of diatoms in the diet of larger juvenile abalone merits reassessment

Feeding Ecology of Juvenile Spiny Lobster, Panulirus interruptus, on the Pacific Coast of Baja California Sur, Mexico

Many aspects of the early life history of the red lobster Panulirus interruptus are little known, including the relationship between habitat structure, food resource availability, and nutrition of juveniles. We investigated the spatial and temporal differences in food intake, diet composition, and nutritional condition of juveniles at two sites along the Pacific coast of the Baja California Peninsula (Mexico) with contrasting oceanographic and biological conditions. One site (Arvin) is located inside a protected bay, Bahia Tortugas, where the waters are cooler and temperate seagrasses and macroalgae are the dominant benthic flora. The second site (Queen) in Bahia Sebastian Vizcaino was located along a more open coastline where seawater temperatures were higher and the benthic flora more indicative of warmer seas. At both sites, we randomly sampled epifauna within vegetated habitats to estimate the seasonal availability of food resources for juvenile lobsters from autumn 2001 until summer 2002. Concurrently, we used traps to sample P. interruptus juveniles for stomach content analysis. At both sites, Amphipoda, Gastropoda, and Polychaeta dominated the epifauna assemblages, as determined by an Index of Importance. Juvenile P. interruptus primarily consumed crustaceans (mostly amphipods and isopods) and vegetal material (surf-grass Phyllospadix spp. and calcareous algae), but their food spectrum was wide. Manly\u27s Index of Resource Selection indicated that lobsters preferred some prey (e.g., Brachyurans) over others despite their low Index of Importance. Despite marked differences in the types of food and their availability between sites, there were no significant differences in the nutritional condition (e.g., relative weight of the digestive gland) of lobsters at the two sites. However, the nutritional condition of lobsters was effected during some seasons. In particular, their condition deteriorated during the spring (April 2002) at Arvin, as did the proportion of individuals with empty stomachs. This study shows the feeding adaptation capacity of the juvenile California spiny lobster P. interruptus to different environmental conditions prevalent in Centre Baja California Peninsula

Riqueza de especies y composición de los ensambles de macroalgas de un arrecife de coral impactado en el Golfo de California, México

Background and Aims: In September 2001, the coral reef of the San Lorenzo Channel, La Paz Bay, Gulf of California, Mexico, was affected by the stranding of the oil tank vessel “Lázaro Cárdenas II”. Soon afterwards, hurricane “Juliette” hit the area with strong winds and water movement, disturbing the reef again. After that, three zones could be observed in the reef: one directly impacted by the shipwreck, one indirectly impacted by the hurricane, which moved and accumulated the coral debris left by the shipwreck, and the third one, which was not impacted. Later, a monitoring program was established to determine the degree of recovery of macroalgal assemblages in both impacted zones compared with the non-impacted one. Methods: From February 2005 to December 2007, macroalgae were collected seasonally by scuba divers in the three zones. In each zone, three to five thalli of all conspicuous algae, five rocks and five fragments of dead coral covered with macroalgal turfs were collected. Species number and composition of macroalgae assemblages were compared between zones and between years. Key results: A total of 117 species were found, 70 belonged to the phylum Rhodophyta, 25 to Ochrophyta-Phaeophyceae, and 22 to Chlorophyta. Macroalgal species richness and composition of the impacted zones were not different from the control zone, even between years. Conclusions: Macroalgal assemblages in the San Lorenzo Channel coral reef were able to recover, regardless of the modification of the substrate caused by the stranding and the hurricane “Juliette” in 2001. Therefore, it is important to implement monitoring efforts in case of anthropogenic or natural disturbance to document the extension of damage, recovery of the communities, and propose mitigation strategies if necessary.  Antecedentes y Objetivos: El arrecife de coral del Canal de San Lorenzo, Bahía de La Paz, Golfo de California, México, se vio afectado por el varamiento del tanque petrolero “Lázaro Cárdenas II” en septiembre de 2001. Poco después, el huracán “Juliette” golpeó el área con fuertes vientos y movimiento de agua que perturbaron nuevamente al arrecife. Después de esto, se pudieron observar tres zonas en el arrecife: una directamente impactada por el encallamiento, otra indirectamente impactada por el huracán, que movió y acumuló los restos de coral que dejó el encallamiento, y la tercera no impactada. Posteriormente, se estableció un programa de monitoreo para determinar el grado de recuperación de los ensambles de macroalgas en ambas zonas impactadas en comparación con la zona no impactada. Métodos: De febrero de 2005 a diciembre de 2007, se recolectaron estacionalmente macroalgas en las tres zonas por medio de buceo. En cada zona, de tres a cinco talos de las especies de macroalgas conspicuas, cinco rocas y cinco fragmentos de coral muerto cubiertos con tapetes macroalgales fueron recolectados. El número de especies y la composición de los ensambles de macroalgas fueron comparados entre zonas y entre años. Resultados clave: Se encontró un total de 117 especies, 70 pertenecientes al filo Rhodophyta, 25 a Ochrophyta-Phaeophyceae y 22 a Chlorophyta. La riqueza de especies y composición de las macroalgas en las zonas impactadas no fueron diferentes de la zona control ni entre años. Conclusiones: Los ensambles de macroalgas en el arrecife de coral del Canal de San Lorenzo pudieron recuperarse independientemente de la modificación del sustrato a causa del varamiento del buque y del huracán “Juliette” en 2001. Por lo anterior, es importante implementar esfuerzos de monitoreo para que, en caso de que ocurra una perturbación antropogénica o natural, se pueda documentar la extensión del daño, la recuperación de la comunidad y proponer estrategias de mitigación si es necesario

Composición y abundancia de florecimientos macroalgales y su relación con variables ambientales en una bahía subtropical en el Golfo de California

Background: In La Paz Bay macroalgae blooms have an important presence. Goal: Analyze the relationship of the most abundant macroalgae in algal blooms with environmental variability in a subtropical bay over two years. Methods: Temperature, salinity, nutrients (DIN, NT, PO4 -3 and PT) and macroalgae samples were taken every three months, during 2010 and 2011, at four sites with conspicuous growth of macroalgae. Total and mean biomass (wet weight) of important species was estimated by placing three transects perpendicular to the coast, divided into five equidistant points each. At each point four quadrants (0.25 m2 ) were placed randomly and macroalgae were manually collected. Statistical analyzes were performed to estimate significant differences between years, months and sites of the environmental variables, nutrients, and biomass. A principal component analysis was performed, to observe the relationship between biomass and environmental variables and nutrients. Results: Nine macroalgae species, plus one cyanoprokaryonte showed a biomass greater than 1 g m-2. Acanthophora spicifera, Caulerpa verticillata and Spyridia filamentosa were the most abundant species. A. spicifera and G. vermiculophylla were related with nutrient concentrations, and salinity. While Ulva ohnoi showed that it was not related either to environmental or nutrient concentrations. Conclusion: The bloom forming macroalgae A. spicifera, C. verticillata and S. filamentosa are consistent with genera previously reported as bloom-formers in nutrient-rich coastal waters.Antecedentes: En la Bahía de La Paz los florecimientos de macroalgas tienen una presencia importante. Objetivo: Analizar la relación de las macroalgas más abundantes en los florecimientos algales, con la variabilidad ambiental en una bahía costera a lo largo de dos años. Métodos: Se tomaron muestras de temperatura, salinidad, nutrientes (DIN, NT, PO4 -3 y PT) y macroalgas cada tres meses, durante 2010 y 2011, en cuatro sitios con crecimiento notorio de macroalgas. La biomasa total y media (peso húmedo) de las especies abundantes se estimó colocando tres transectos perpendiculares a la costa, divididos en cinco puntos equidistantes cada uno. En cada punto se colocaron aleatoriamente cuatro cuadrantes (0.25 m2 ) y se recolectaron manualmente las macroalgas. Se realizaron análisis estadísticos para estimar diferencias significativas entre años, meses y sitios de las variables ambientales, nutrientes y biomasa. Se realizó un análisis de componentes principales, con el fin de observar la relación entre la biomasa y las variables ambientales. Resultados: Nueve especies de macroalgas, más un cianoprocarionte presentaron una biomasa mayor a 1 g m-2. Acanthophora spicifera, Caulerpa verticillata y Spyridia filamentosa fueron las especies más abundantes. A. spicifera y G. vermiculophylla mostraron relación con las concentraciones de nutrientes y la salinidad. Mientras que, Ulva ohnoi no mostró relación con las concentraciones ambientales o de nutrientes. Conclusión: Las macroalgas que forman florecimientos A. spicifera, C. verticillata y S. filamentosa coinciden con los géneros previamente reportados como formadores de florecimientos en aguas costeras ricas en nutrientes

Species composition and seasonal changes in macroalgal blooms in lagoons along the southeastern Gulf of California

Abstract Species composition and seasonal changes in macroalgal blooms in six coastal lagoons highly impacted by human activities were tracked for the three seasons between May 2004 and April 2005. Though temperatures were lower during the cold season than during the dry and rainy seasons and some locations showed variations in salinity during the rainy season, nutrient concentrations showed no defined pattern and varied according to season and location. A total of 10 seaweed species and the cyanobacterium Microcoleus lyngbyaceus had biomasses )1 g m -2 dry weight, but only four species represented )1% of the annual biomass. During the dry season, Spyridia filamentosa had the highest biomass (57.5 g m ). Abundances of these species were higher than previously reported for this region. Correlation analyses showed a positive correlation between total phosphorus and the biomass of G. vermiculophylla, suggesting that this nutrient might be limiting its growth. C. sertularioides abundance had a positive correlation with N:P ratios, suggesting that high concentrations of nitrogen relative to low phosphorus levels favor its growth. These analyses revealed that nutrient concentrations are most likely to affect macroalgal growth, but temperature and salinity also play a role. This information may be useful for monitoring future blooms and determining changes over time

Macroalgas marinas bentónicas de Isla Gudalupe, Baja California, México

Background. The last floristic survey of marine algae species from Guadalupe Island was published in the 1980s, including a summary of surveys from collections dating back to the beginning of the past century. Goals. To update the species inventory and analyze the macroalgae community on Guadalupe Island. Methods. Four sampling procedures were undertaken, during January, April, and October 2013, and May 2014, from intertidal and subtidal zones, at depths of between 10 and 18m, depending on the locality. Results. 102 species were identified as representatives of the threemain taxonomic divisions; 14 species belonging to Chlorophyta, 29 to Ochrophyta, and 59 to Rhodophyta, related to 39 families and 65 genres. Of the organisms found at a specific level, 30 are new records, 13 are taxonomically synonymous, and 59 correspond to previous registries. The Margalef index shows that the highest biologic richness occurred in May 2014, as while the highest diversity also appeared in that same month, as the Shannon-Wiener index indicates. Data were statistically evaluated with the PERMANOVA analysis, showing statistical differences between the analyzed factors(depth, season, zone, and locality), thus demonstrating high heterogeneity at the localities, mainly between the northern and western areas of the island. Conclusions. Guadalupe Island has high species richness and diversity. In accordance to SIMPER analysis, the species that contribute most to the qualitative differences found in the analyzed factors are Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata, and Padina durvillei.Antecedentes. El último inventario florístico de algas marinas de Isla Guadalupe se publicó en la década de 1980, e incluye una recopilación de trabajos de colecciones de principios del siglo pasado. Objetivos. Realizar un inventario y un análisis actualizado de la comunidad de macroalgas de Isla Guadalupe. Métodos. Se efectuaron cuatro muestreos durante los meses de enero, abril y octubre del 2013 y mayo del 2014, en la zona intermareal y en la submareal, a 10 y 18 m de profundidad, dependiendo de la localidad. Resultados. En total se determinaron 102 especies, entre las que se encuentran representantes de las tres principales Divisiones taxonómicas: 14 especies de la División Chlorophyta, 29 especies de la División Ochrophyta y 59 especies de la División Rhodophyta, las cuales se relacionan con 39 familias y 65 géneros. De los organismos determinados a nivel específico, 30 corresponden a nuevos registros, 13 con sinonimia taxonómica y 59 especies están previamente registradas. De acuerdo con el índice de Margalef, durante mayo del 2014 se presentó la mayor riqueza biológica, en este mismo periodo, según el índice de Shannon-Wiener, se encontró una mayor diversidad. Los datos se analizaron estadísticamente con el análisis PERMANOVA, el cual mostró diferencias significativas entre los factores examinados de profundidad, temporada, zona y localidad de muestreo, lo que indica una alta heterogeneidad entre las localidades, principalmente entre la zona norte y la oeste de la isla. Conclusiones. Isla Guadalupepresenta una gran riqueza y diversidad biológica. De acuerdo con el análisis SIMPER, las especies que más contribuyen a las diferencias cualitativas de los factores analizados son Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata y Padina durvillei

Natural Diet of Juvenile Abalone Haliotis fulgens and H. corrugata (Mollusca: Gastropoda) in Bahia Tortugas, Mexico

Diet of juvenile (10-100 mm in length) abalone (Haliotis fulgens and H. corrugata) in their natural environment was examined in specimens collected at Bahia Tortugas, Baja California Sur. Nine macroalgae species, one polychaete worm, one amphipod, one hydrozoan, and one sea grass were identified. A high percentage of stomachs analyzed were empty. In those with contents, Phyllospadix torreyi (Anthophyta), Laurencia sp., Gelidiales (Rhodophyta), and Phaeophyta (Dictyotales) were the most common items. Most specimens with macroalgal material came from depths in which H. fulgens (shallow) and H. corrugata (>6 m) are more abundant. Benthic diatoms were almost absent from ingested material