High genetic differentiation in the edible cannonball jellyfish (Cnidaria: Scyphozoa: Stomolophus spp.) from the Gulf of California, Mexico

To describe the annual cycle of Sargassum horneri in Mexican waters, we selected two sites differing in their degree of wave exposure and sediment type: Rincon de Ballenas (RB), and Rancho Packard (RP). From June 2009 to April 2010 we followed the seasonal changes in S. horneri density and biomass along two intertidal transects per site. The effects of this non-indigenous species on the local macroalgae community were assessed by comparing their species composition, density, biomass, species richness, and diversity index in quadrats with and without S. horneri. There were significant differences in S. horneri density and biomass between sites (P < 0.001). At RB the invasive alga density average was 2 ± 0.94 individual m-2, with a mean biomass of 4 ± 0.95 g DW m-2. At RP, S. horneri density average was 10 ± 0.96 individual m-2, and mean biomass of 102 ± 0.97 g DW m-2. At RB, the invasive alga promoted a significant reduction in the four selected structural variables, and the corticated macrophytes and the foliose functional forms were severely reduced. At RP, there were only marginally significant effects (P = 0.06) of S. horneri presence on the local macroalgae community, and higher density, biomass, and diversity values were found when S. horneri was present. Most of the functional forms were found, even if the invasive alga was present. At both locations, the highest biomass corresponded to the articulated calcareous functional form. These contrasting results could be due to the fact that the native macroalgae community has already been altered by the early invasion of S. muticum, with the most resilient species and functional forms remaining in place. One of the most important changes we noticed is the severe reduction of the canopy forming species at both sites.

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Presence of Sargassum horneri at Todos Santos Bay, Baja California, Mexico: its effects on the local macroalgae community.

To determine the structure of the epiphytic diatom assemblage and its potential time variations on apical blades of Macrocystis pyrifera from the coasts of the Baja California peninsula four fronds of M. pyrifera were collected monthly from February to August 2003 in El Sauzal, B.C.; the diatoms from 5 blades per frond were mounted on permanent slides and examined floristically and quantitatively. The structure of the assemblage followed the general pattern for most diatom associations, i. e., few abundant species and many rare or uncommon taxa. Species richness reached 171 diatom taxa, however S per sample was heterogeneous (6 - 51 taxa) and in general low. Also, low values of diversity and equitability were estimated: H ´ = 2.1 (max = 3.8, min = 0.3), and J ´ = 0.45. The most abundant taxa were Rhoicosphenia genuflexa (Kutzing) Medlin, Gomphonemopsis pseudexigua (Simonsen) Medlin, tabularia investiens (W.Smith) Williams & Round, and cocconeis costata var. pacifica (grunow) grunow. All are considered permanent constituents of the diatom assemblage on

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Cambios en la estructura de la asociación de diatomeas Epifitas de Macrocystis pyrifera (L.) C. Ag.

Analysis of the Gulf of California cannonball jellyfish fishery as a complex system

Pigments are present in a broad variety of terrestrial and aquatic organisms. The cannonball jellyfish (Stomolophus sp. 2) is an important fishery resource in the northwest of Mexico and is processed to be traded and consumed as seafood. During the process, water with a soluble blue pigment and other compounds are discarded to the environment. In this work, we present some properties of the blue pigment from Stomolophus sp.2 (S2bp), to decide if it could be considered as a potential value-added waste and avoid the blue proteinaceous pigment wastewater. S2bp was purified to homogeneity and had a molecular mass of 28.0 kDa; this protein exhibited a ʎmax at 650 nm, contained Zn2+ and Cu2+ metal ions, and was stable from 10 to 50 °C and in a pH range of 3.0 to 13.0 for 1 h. It had halotolerant characteristics maintaining the blue coloration in a broad range of ionic strength (0–4 M NaCl) and showed changes in ʎmax with chaotropic salts. In addition, S2bp was stable in the presence of organic acids and EDTA and in zwitterionic, anionic, and nonionic detergents at critical micellar concentration. However, oxidant reagents like NaClO and H2O2 decrease the coloration. These results show that the jellyfish pigment is a stable protein which makes it an alternative pigment for the food industry.

Characterization of cannonball jellyfish (Stomolophus sp. 2) blue protein: a pH-stable pigment.

espanolEl objetivo de esta investigacion fue conocer el rol de los actores involucrados en la pesqueria de medusa bola de canon, en Guaymas, Sonora. Con el metodo bola de nieve se realizaron entrevistas semiestructuradas, luego se jerarquizaron mediante la red de poder/ interes de cuatro cuadrantes, y se relacionaron con una matriz de vinculacion. El resultado arrojo que el Instituto Nacional de Pesca, los compradores, procesadores, comercializadores y las cooperativas pesqueras son los actores clave, con mayor interes e influencia en el manejo de la pesqueria. El presente analisis es util para establecer y mejorar el manejo de la captura de medusa. Se concluye que existe una relacion conflictiva y de poca cooperacion entre los actores mencionados, lo cual impide que se respeten las estrategias de manejo para explotar la medusa en condiciones de sustentabilidad. EnglishThe aim of this research was to know the role of stakeholders involved in the cannonball jellyfish fishery in Guaymas, Sonora. Using the snowball method, semi-structured interviews were conducted, then hierarchized through the power / interest network of four quadrants, and related to a connection matrix. The result showed that the National Fishery Institute, buyers, processors, marketers and fishing cooperatives are the key players, with greater interest and influence in the management of the fishery. This analysis is useful to establish and enhance the management of jellyfish catch. It follows that there is a conflictive relationship and little cooperation among the said stakeholders, which prevents management strategies to exploit jellyfish fishing in conditions of sustainability from being respected.

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Análisis de actores de la pesquería de medusa en Guaymas, Sonora

Aerial photographs from INEGI for October 1970, October 1985, July 1989 and September 1991 were analyzed to calculate the cliff retreat rate and sediment volume supplied to the coastal system in four coastal sectors of Todos Santos Bay: San Miguel, El Sauzal, Punta MorroiEl Vigia and Punta Banda. Results indicate that all four sectors are under erosion, with cliff retreat rates of 0.93, 0.97. 0.70 and 0.89 miyr, and sediment volumes of 14.097.71, 13,996.16, 3,919.14 and 16,194.43 m3/yr, respectively. The cliffs are important for maintaining the sediment budget of the coastal zone in Todos Santos Bay.

Erosión y aporte sedimentario de los cantiles marinos de la bahía de todos santos, baja california, en el periodo de 1970 a 1991 erosion and sediment supply of sea cliffs of todos santos bay, baja california, from 1970 to 1991

María Esther Cruz-Colín

Papers

Análisis de actores de la pesquería de medusa en Guaymas, Sonora

Erosión y aporte sedimentario de los cantiles marinos de la bahía de todos santos, baja california, en el periodo de 1970 a 1991 erosion and sediment supply of sea cliffs of todos santos bay, baja california, from 1970 to 1991