Mass fish die-off during a diatom bloom in the Bahía de La Paz, Gulf of California

Mortalidad masiva de peces durante un florecimiento de diatomeas en La Bahía de La Paz, Golfo de California

David Javier López-Cortés¹, Erick Julián Núñez-Vázquez^1,2, Christine Johanna Band-Schmidt³, Ismael Gárate-Lizárraga³, Francisco Eduardo Hernández-Sandoval¹ and José Jesús Bustillos-Guzmán¹

¹ Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita, La Paz, B.C.S. 23096, México.

³ Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Av. Instituto Politécnico Nacional s/n, Col. Playa Palo de Santa Rita, La Paz, B.C.S. 23096, México. e-mail: dlopez04@cibnor.mx

Recibido: 26 de febrero de 2014.
Aceptado: 25 de abril de 2014.

Abstract

An unusual fish die-off occurred during a bloom of diatoms from June 10^th -July 3^rd 2006 in Bahía de La Paz in the Gulf of California. The prevalent organisms were Pseudo-nitzschia spp. (2.4 x 10⁶ cells L^-1), Thalassiosira eccentrica (2.3 x 10⁶ cells L^-1) and Chaetocerosspp. (9.65 x 10⁵ cells L^-1). Three toxic species were identified: P. pseudodelicatissima-complex, P fraudulenta, and P. pungens. Fucoxanthin was the dominant pigment during the bloom, peaking at 9.3 μg L^-1. Sea surface temperature dramatically increased from 19.0 °C to 27.0 °C during the bloom, with inorganic nitrogen (1.0 ± 0.6 μM) and Si(OH)₄ (15.5 ± 8.0 μM). Low content of domoic acid measured by HPLC-UV from net samples ranged from 24.0 to 52.0 ng per filter and tissue of the chocolate clam Megapitaria squalida (0.55 μg g^-1) and the white clam Dosinia ponderosa (0.06 μg g^-1). Domoic acid analysis of dead fish tissues was negative. Fish necropsy indicated that death by asphyxia was probably caused by Thalassiosira eccentrica and Chaetoceros spp. Alternate mixing processes and instability of the water column, as well as sudden changes of both temperature and nutrients created conditions for proliferation of the diatoms.

Keywords: Domoic acid, fish mortality, Gulf of California, Pseudo-nitzschia, Thalassiosira.

Una inusual muerte masiva de peces sucedió durante un florecimiento de diatomeas ocurrido del 10 de junio al 3 de julio en la Bahía de La Paz, Golfo de California. Los organismos dominantes fueron Pseudo-nitzschia spp. (2.4 x 10⁶ cels L^-1), Thalassiosira eccentrica (2.3 x 10⁶ cels L^-1) y Chaetoceros spp. (9.65 x 10⁵ cels L^-1). Se identificaron tres especies tóxicas: una pertenece al complejo P. pseudodelicatissima, P. fraudulenta y P. pungens. La fucoxantina, con un pico de 9.3 μg L^-1, fue el pigmento dominante durante el florecimiento. La temperatura superficial del mar en el transcurso del evento drásticamente se incrementó de 19.0 °C a 27.0 °C, con valores de nitrógeno inorgánico de 1.0 ± 0.6 μM y Si(OH)₄ de 15.5 ± 8.0 μM. El contenido de ácido domoico determinado por HPLC-UV fue bajo tanto en muestras de red con un rango de 24.0 a 52.0 ng por filtro como en tejido de almeja chocolata Megapitaria squalida (0.55 μg g^-1) y almeja blanca Dosinia ponderosa (0.06 μg g^-1). El análisis de ácido domoico en tejido de peces fue negativo. La necropsia de peces sugiere que la muerte por asfixia probablemente la causó Thalassiosira eccentrica. y Chaetoceros spp. Procesos de mezcla alternantes y la inestabilidad de la columna de agua, así como cambios bruscos de temperatura y nutrientes, propiciaron condiciones para la proliferación de las diatomeas.

Palabras clave: Ácido domoico, mortalidad de peces, Golfo de California, Pseudo-nitzschia, Thalassiosira.

INTRODUCTION

As in other parts of the world, harmful algal blooms in the Gulf of California have increased over the last two decades (Cortés-Altamirano & Licea-Durán, 2004; Gárate-Lizárraga et al., 2009). The primary harmful group dinoflagellates. However, diatoms also develop harmful algal blooms (Licea-Durán et al., 1999). Different species of diatoms like Thalassiosira and Chaetoceros are noxious, especially for farmed fish, while others like several species of Pseudo-nitzschia H. Peragallo are toxigenic (Smayda, 2006; López-Cortés et al., 2006; García-Mendoza et al., 2009).

The genus Thalassiosira own to centric diatoms which has one of the greater number of species, with > 100, some of which form mucilaginous colonies (Harris et al., 1995) and can produce harmful algal blooms that generate anoxia. Some species of the genus Chaetoceros have long robust setae with spinules that, even in low densities, can produce mechanical damage in fish gills; the fish react producing mucus which leads to asphyxia (Albright et al., 1993). The species of the genus Pseudo-nitzschia are limited to marine environments and have wide global distribution (Hasle et al., 1996). Their presence is associated with eddies, upwellings, and post-upwelling conditions (Anderson et al., 2006; Schnetzer et al., 2007).

Presently, 37 species of Pseudo-nitzschia have been described, of which 14 produce domoic acid (DA) (Trainer et al., 2012). Seven of these toxigenic species can be found along the west coast of Mexico. These are P. fraudulenta (Cleve) Hasle, P. pseudodelicatissima-complex, P. australis Frenguelli, P. multiseries (Hasle) Hasle, P. delicatissima (Cleve) Heiden, P. pungens (Grunow ex Cleve) Hasle and P. brasiliana (Lundholm, Hassle and Fryxell) (Lange et al., 1994; Hernández-Becerril et al., 2007; Gárate-Lizárraga et al., 2007, 2013; Quijano-Scheggia et al., 2011; Table 1). Fish can accumulate DA in their viscera and body tissues without toxic effects (Lefebvre et al., 2012), and they are the principal vectors of transferring DA to higher trophic levels (Trainer et al., 2012; Lefebvre et al., 2012). However, the relation between nutrient concentration in the environment and production of DA remains unclear (Trainer et al., 2009; Lewitus et al., 2012).

Along the west coast of Mexico, DA has been associated with the death of marine mammals and seabirds in several zones (Table 1). Data of the exact environmental conditions associated with these events are scarce, but factors have been found to include wind-driven upwelling and a high ratio of Si(OH)₄:N (García-Mendoza et al., 2009). Moreover, the specific conditions that trigger the dominance of Pseudo-nitzschia during these blooms, its production of DA, its oceanographic and meteorological conditions are unclear and may be complex (Lewitus et al., 2012). In the southern part of the Bahía de La Paz, a diatom bloom in 2006 occurred during the first 10 days of June, which included different species of Pseudo-nitzschia (Gárate-Lizárraga et al., 2007), one species of Thalassiosira and Chaetoceros spp. (Guluarte-Castro & Bañuelos, 2007; Núñez-Vázquez et al., 2011). The aim of this paper is to describe the hydrographic conditions, related to the diatom bloom dominated by DA producing Pseudo-nitzschia spp., which co-occurred with Thalassiosira sp., and Chaetoceros spp., and to clarify the causes of massive fish death along the southern coast of Bahía de La Paz during summer 2006.

Study area and sampling sites. Bahía de La Paz is located between 24°06' and 24°47" N, 110°18" and 110°45' W, along the southeastern coast of the Baja California Peninsula, ~180 km north of the mouth of the Gulf of California. In the southern part of the bay, a bloom occurred and subsequently, daily sampling was carried out, from June 20^th through July 3^rd 2006. Six sites were chosen (Fig. 1): Barco Hundido (BH), El Mogote (EM), Punta Mogote (PM), Marina Palmira (MP), El Caimancito (EC), Punta Prieta (PP), and Balandra (BA).

Sampling, quantification, and identification of phytoplankton. Water samples (n= 19) were collected with Van Dorn bottles at the sea surface. Station EM samples were taken at the surface and 4.5 m. Only at station EC dead fish were collected. One liter of seawater samples from each station were preserved with a Lugol-acetate solution for quantifying (Utermöhl, 1958) and identifying phytoplankton cells. Dominant species were quantified only in samples with high concentrations of chlorophyll a (15.0-23.0 mg m^-3) and fucoxanthin (fingerprints of diatoms) (5.8-9.3 mg m^-3). Species were identified using an Olympus CH2 light microscope and an inverted Zeiss microscope. Vertical trawls were performed with a 20 um mesh phytoplankton net at stations EM and PM, where the water was more discolored. An aliquot from these samples was used to identify species with a light microscope (40x) and a scanning electron microscope (see Gárate-Lizárraga et al., 2007). Another part of the net samples was used to analyze DA.

Toxin Analysis. Three concentrated (0.5-1.0 g) phytoplankton samples were collected by net trawling and was used to determine the probable presence of amnesic toxins by mouse bioassay, following the recommendations described by Lawrence et al. (1989), based on the mouse bioassay for PSP (Association of Official Analytical Chemists, 1995; Food and Agricultural Organization of the United Nations, 2005). BAL/c strain mice (18-22 g) from the CIBNOR animal laboratory were injected intraperitoneally with 1 mL of each extract. Animals were kept under observation for 48 h, and their clinical signs were recorded.

Bivalves. At station EM, chocolate clam Megapitaria squalida (Sowerby, 1835) and the white clam Dosinia ponderosa (Gray) 1838 were collected at a depth of 3.0 to 6.0 m for determining concentration of domoic acid for HPLC-UV (Hummert et al., 1997).

Chemical analysis. An aliquot of 30 mL of a sample collected from two net trawls was filtered through a Whatman GF/F glass fiber filter in order to subsequently measure DA concentrations. Filters and bivalves tissue were macerated separately with a methanol/water solution (50:50 v:v) and later quantified by high performance liquid chromatography (HPLC-UV) (model HP 1100, Agilent Technologies, Santa Clara, CA) following the method described by Hummert et al. (1997). Identification was achieved by comparing the retention time of the sample with that of the DA standard (National Research Council Canada, Institute for Marine Biosciences, Certified Reference Materials Program, Halifax, NS, Canada). Quantification was performed according to the calibration curve of the standard.

Fish samples. At station EC, photographs and videos of dead or dying fish were taken for identification and clinical signs. Unfortunate only three specimens of dead fish Mugil cephalus (Linnaeus, 1758), Eucinostomu ssp. and Pomadasys macracanthus (Gunther, 1864) were in good enough conservation conditions for necropsy and toxicological analyses by mouse bioassay. Samples were stored at -20 °C before testing and examination At the laboratory, 10 g of viscera and muscle were excised, applying the extraction process for DA described for pellets derived from the phytoplankton tows, except that the viscera and muscle were homogenized at pH 3.0 (Polytron, Kinematica).

Environmental conditions. Temperature (± 0.1 °C) was measured with a bucket thermometer and satellite images of surface sea temperature were downloaded from NOAA CoastWatch program. From the water samples, 500 mL were filtered through a 0.7 um glass fiber filter (GF/F Whatman, Maidstone, UK) and used to measure NO₂-, NO₃-, NH₄+, PO₄³-, and Si(OH)₄ with a continuous flow ion autoanalyzer (Quik Chem Series 8000, Lachat Instruments, Loveland, CO), as described in Strickland and Parsons (1972). Total dissolved inorganic nitrogen (Ntotal) is the sum of the nitrogen compounds (NO₂^-+NO₃-+NH₄+). The material retained by the GF/F filters was used to identify and quantify photosynthetic pigments by HPLC-UV (model HP 1100, Agilent Technologies, Santa Clara, CA) following the method described by Vidussi et al. (1996). Wind data (direction and speed) was obtained from the CIBNOR meteorological station (http://www.cibnor.gob.mx/meteo/ecibmet.html).

RESULTS

Toxin analysis. Preliminary toxicological analysis by mouse bioassay showed that DA was present in the concentrated net phytoplankton samples. Clinical signs in mice were hypoactivity, difficult breathing, and paralysis of hindquarters. Three mice scratched themselves (ears and shoulders), seven mice had mild to severe shivering, lack of motor coordination and death came within 24 h with the equivalent of >40 μg DA. Symptoms match those described for amnesic shellfish toxins (FAO, 2005). Cyanosis in extremities (mainly in the tail) was also present. Concentrations of DA quantified with HPLC-UV varied from 24.0-52.0 ng filter^-1 from plankton tows and 0.55 μg g^-1 of tissue in the chocolate clam M. squalida and 0.06 μg g^-1 of tissue in the white clam D. ponderosa (Table 1). These concentrations are below the Mexican health standard NOM 242-SSA1-2009 (DOF, 2010), which stipulates that 20 mg kg^-1 DA have to be present in tissue before a fishery can be closed.

Fish examinations. Unfortunately by the advanced decomposition state of the fish samples, only three individuals were in good enough conditions to be analyzed. Post-mortem examination of the fish showed congestion and mucus in the gills. The gills had epithelial damage probably caused by Chaetoceros spp. setae and by a large accumulation of Thalassiosira eccentrica, which caused asphyxia and death. No toxicity (no clinical signs were recorded) was detected in fish viscera and muscle by mouse bioassay.

Environmental conditions. Satellite images of Bahía de La Paz had SSTs of -27.0 °C on June 1^st 2006 (Fig. 3a); seven days later, the temperature declined to 19.0-20.0 °C (Fig. 3b); on June 14^th 2006, temperature increased by 5.0 °C to 24.0-25.0 °C (Fig. 3c). On June 28^th, temperatures were 28.0-29.0 °C (Fig. 3d). Temperatures recorded at stations in the southern part of the bay during the diatom bloom were 19.0 °C on June 10^th. After June 20^th, temperature averages were -around 25.0±1.5 °C and at the end of the month, 27.0-28.0 °C.

A seasonal wind, confined to the area around La Paz, comes from the south, starting in early evening and lasting through midmorning (the "Coromuel"). Daytime winds during the day are typical sea breezes from the northeast. Clearly at the beginning of June, evening winds were relatively high, with a velocity from 3.5 to 5.0 ms^-1. The diatom bloom was detected during this period.

Concentrations (in μM) of NO₂^-, NO₃^-, NH₄⁺, PO₄³-, and Si(OH)₄ ranged from 0.1-0.183, 0.1-2.71, not detectable to 0.5, 0.073-1.44, and 2.94-28.70, respectively. N_total fluctuated between 0.70 and 3.31 μM during the sampling period. Between June 20^th-23^rd, two peaks of 3.31 and 2.69 μM were recorded at station EM (Fig. 4). Figure 4 also shows that N:P ratios were relatively low (0.65 to 6.0).These values are low, compared with the Redfield N:P ratio. Some ratios of Si(OH)₄:N (4-28) and Si(OH)₄:P (5-56) during the study were higher than the Si:P Redfield ratio (16:16:1; Si:N:P) (Fig. 5).

DISCUSSION

The high abundance of Pseudo-nitzschia genus and detection of DA, suggests that some of the species are the source of DA. Trainer et al. (2012) report that some species of this genus are toxic, nevertheless other species produce low levels of toxins (Bates, 1998), such as P fraudulenta, P. pungens Hasle, and P. pseudodelicatissima (Hasle) Hasle. These species were identified in this work, with the former dominating in abundance. The low production of DA of these species could explain the low levels of DA detected in the phytoplankton net and in the bivalves samples during this event.

Temperatures recorded during this investigation (thermal satellite images) were variable. During this period there were wide temperature changes; Thalassiosira and Pseudo-nitzschia were most abundant. When abundance declined on June 28^th, the thermal range was 27.028.0 °C. Aguirre-Gómez et al. (1999) reported that sudden changes in temperature can lead to the rapid growth of toxic species in particular, since many of these are capable of enduring variations with the added benefit of not facing competition. During this period of thermal change, we suspect that the conditions for this bloom of diatoms were met, including sufficient nutrients and low competition for nutrients.

Pseudo-nitzschia species tolerate a wide temperature range from 2.0 to 28.0 °C (Hallegraeff,1993), and some species bloom at very narrow temperature ranges, such as P. australis that has been found to bloom at 14.0 °C in the northern Baja California Peninsula (García-Mendoza et al., 2009). During this study temperature varied over a wide range (19.0-27.0 °C) when Pseudo-nitzschia spp. bloom occurred in Bahía de La Paz.

Pigment signatures of different phytoplankton groups have been a useful tool for identification and detecting algae blooms. We found high concentrations of chlorophyll a and fucoxanthin fingerprint in the diatoms (Jeffrey & Vesk, 1997) and these peaked at the same time at the peak abundance of the three prominent genera. While correlation between chlorophyll a and fucoxanthin was high and significant (r = 0.78).

Wind-driven upwelling events can produce appropriate conditions for proliferation of different species of Pseudo-nitzschia (Gárate-Lizárraga et al., 2007; García-Mendoza et al., 2009). When southeastern winds were dominant (> 3.5 ms^-1), it was evident that species of Pseudo-nitzschia, Thalassiosira eccentrica, and Chaetoceros spp. proliferated. A similar situation was recorded during a bloom of Chaetoceros debilis (Cleve 1894) in June 2003 in the Bahía de La Paz (López-Cortés et al., 2006).

In Bahía de La Paz, among other factors, winds promote mixing of the water column (Obeso-Nieblas et al., 2008), bringing nutrients to the surface. Samples had a range of concentrations of NO₃^- (0.1 to 2.72 μM); PO₄^3- (0.073 to 1.44 μM) and Si (OH)₄ (2.94 to 28.70 μM). According to Egge and Aksnes (1992), diatoms are dominant when Si (OH)₄ is >2.0 μM. Although N:P ratios were low (0.65-6.0), some Si (OH)₄:N (4.0-28.0) and Si (OH)₄:P (5.0-56.0) ratios were high, compared with Redfield's stoichiometric (16:16:1; Si:N:P), under these conditions, the diatom bloom is likely to have been generated by the higher concentrations of NO₃^- and Si (OH)₄, as well as temperature conditions.

Anderson et al. (2006) report that, when the Si(OH₄):NO₃^- ratio is higher than the Redfield ratio, particulate DA and cellular DA of phytoplankton were low; also, that the reduction of the Si(OH₄):NO₃^- ratio increased DA content in cells. From their observations, we conclude that the high concentrations of silicic acid in Bahía de La Paz (15.4±9.0 μM) and the high Si(OH)₄:DIN ratio was reflected in the low concentrations of DA in our net samples (24-52 ng per filter^-1). Although Smayda (2006) concluded that regulation of DA synthesis is complex and affected by many environmental factors.

The main vectors of DA at other trophic levels are filter-feeding organisms, such as bivalves and some fish. Omnivorous and planktivorous fish can accumulate DA in viscera and body tissues (Lefebvre et al., 2002, 2012), even if they do not present toxicological signs during blooms of normally toxic Pseudo-nitzschia species. In our mouse bioassays of viscera and body tissue of dead omnivorous fish DA was not detected, probably because ingested phytoplankton was low.

In conclusion, this study found that sudden changes in seawater temperature with high concentrations of nitrogen and silicic acid, probably played a role in triggering blooms of noxious and toxic diatoms. Results suggest that Thalassiosira eccentrica and Chaetoceros spp. were responsible for the fish die-off. Although cell counts of Pseudo-nitzschia were high, toxicity levels were low and not enough to cause accumulation of DA in fish. DA was also low in the tested clams. Future work isolating and cultivating of these phytoplankton will be necessary in order to better quantify toxicity under different environmental conditions.

ACKNOWLEDGEMENTS

We thank Ira Fogel of CIBNOR for English editing. We thank Gerardo R. Hernández García for the figures edition. Ariel A. Cruz Villacorta (CIBNOR), Irena Kaczmarska, and James M. Ehrman of the University of Mount Allison, Sackville, NB, Canada for SEM analysis, Amaury Cordero Tapia, Ivan Murillo (CIBNOR), Alejandra Heredia Tapia at Investigación para la Conservación y el Desarrollo A.C. (INCODE), and Iliana Tejeda (CIBNOR) for technical assistance. Research was funded by Consejo Nacional de Ciencia y Tecnología (CONACYT grant 61226 and SEP grant 20130942) and CIBNOR projects PC 0.11 and PC 0.12. Comments and observations on the manuscript of an anonymous reviewer. Ismael Gárate-Lizárraga and Christine J. Band-Schmidt are fellows of COFAA and EDI of the Instituto Politécnico Nacional. Thanks also to native English speaker editor Miguel Cordoba Matson, who provided an invaluable service in polishing up the English in the final version.

REFERENCES

Aguirre-Gómez R, R. Alvarez & 0. Salmerón-García.1999. Red tide evolution in the Mazatlán Bay area from remotely sensed sea surface temperatures. Geofísica Internacional 38 (2): 63-71.         [ Links ]

Albright L. J., C. Z. Yang & S. Johnson. 1993. Sub-lethal concentration of the harmful diatoms, Chaetoceros concavicornis and C. convolutus, increase mortality rates of penned Pacific salmon. Aquaculture 117: 215-225.         [ Links ]

Anderson, C. R., M. A. Brzezinski, L. VVashburn & R. Kudela. 2006. Circulation and environmental conditions during a toxigenic Pseudo-nitzschia australis bloom in the Santa Barbara Channel, California. Marine Ecology Progress Series 327: 119-133.         [ Links ]

AOAC (Association of Official Analytical Chemists). 1995. Official Method 959.08 Paralytic Shellfish Poison, Biological Methods. Final Action. In: Cunniff P. (Ed.). Official Methods of Analysis. 16th edition. Association of Official Analytical Chemists International, Arlington, VA, U.S.A. Press, pp. 21-22.         [ Links ]

Bates, S. S. 1998. Ecophysiology and metabolism of ASP toxin production. In: Anderson, D. M., A. D. Cembella & G. M. Hallegraeff (Eds.). Physiological ecology of harmful algal blooms, NATO ASI Series 41 Springer, Berlin, pp. 405-426.         [ Links ]

Cortés-Altamirano, R. & S. Licea-Durán. 2004. Decoloración en proliferaciones de microalgas como parámetro bioindicador en la Bahía de Mazatlán, México. Revista de Biología Tropical 52 (Suppl. 1): 27-34.         [ Links ]

DOF (Diario Oficial de la Federación). 2010. Norma Oficial Mexicana NOM 242-SSA1-2009. Bienes y Servicios. Productos de la pesca, Moluscos bivalvos frescos, refrigerados y congelados. Especificaciones sanitarias. pp. 1-15.         [ Links ]

Egge, J. K. & D. L. Aksnes.1992. Silicate as regulating nutrient in phytoplankton competition. Marine Ecology Progress Series 83: 281-289.         [ Links ]

FAO (Food and Agricultural Organization of the Unted Nation). 2005. Marine Biotoxins. Food & Agriculture Organization of the United Nations, Study FAO: Food and Nutrition, 80. Rome, Italy, Press, pp. 97-135.         [ Links ]

Gárate-Lizárraga, I., C. J. Band-Schmidt, D. J. López-Cortés, J. J. Bustillos-Guzmán & K. Erler. 2007. Bloom of Pseudo-nitzschia fraudulenta in Bahía de La Paz, Gulf of California (June-July 2006). Harmful Algae News 33: 6-7.         [ Links ]

Gárate-Lizárraga, I., C. J. Band-Schmidt, F. Aguilar-Bahena & T. Grayeb del Alamo. 2009. A multi-species microalgae bloom in Bahía de La Paz, Gulf of California, México (June 2008). CICIMAR Oceánides 24 (1): 15-29.         [ Links ]

Gárate-Lizárraga, I., C. A. Poot-Delgado, E. R. Ramírez-Castillo & M. H. Páez-Hernández. 2013. Proliferation of Pseudo-nitzschia brasiliana and P. cf. pseudodelicatissima (Bacillariophyceae) in the Estero Santa Cruz, northern Gulf of California, México. Revista de Biología Marina y Oceanografía 48 (2): 393-399.         [ Links ]

García-Mendoza, E., D. Rivas, A. Olivos-Ortíz & A. Almazán-Becerril. 2009. A toxic Pseudo-nitzschia bloom in Todos Santos Bay, northwestern Baja California, México. Harmful Algae 8: 493-503.         [ Links ]

García-Mendoza, E., D. Rivas-Camargo, P. Pérez-Brunius, J. Mancera-Flores & J. L. Peña-Manjarrez. 2011. Ácido domoico en material particulado y peces planctívoros de la región de la Bahía de Todos Santos, Baja California, México. Resúmenes, 1er Congreso Nacional de la Sociedad Mexicana para el Estudio de los Florecimientos Algales Nocivos. Mazatlán, Sinaloa, México, p. 33.         [ Links ]

Glibert, P. M., D. M. Anderson, P. Gentien, E. Granéli & K. G. Sellner. 2005. The global complex phenomena of harmful algal blooms. Oceanography 18: 136-147.         [ Links ]

Guluarte-Castro, A. L. & M. A. Bañuelos. 2007. Florecimiento de algas nocivas (Marea roja) en la Bahía de La Paz, Baja California Sur. Red Sanitaria 3: 1-4.         [ Links ]

Hallegraeff, G. M. 1993. A review of harmful algal blooms and their apparent global increase. Phycologia 32 (2): 79-99.         [ Links ]

Harris, A. S. D., L. K. Medlin, J. Lewis & K. J. Jones. 1995. Thalassiosira species (Bacillariophyceae) from a Scottish sea-loch. European Journal of Phycology 30 (2): 117-131.         [ Links ]

Hasle, G. R., C. B. Lange & E. E. Syvertsen. 1996. A review of Pseudo-nitzschia, with special reference to the Skagerrak, North Atlantic, and adjacent waters. Helgolander Meeresunters 50: 131-175.         [ Links ]

Hernández-Becerril, D. U., E. Bravo-Sierra & J. A. Aké-Castillo. 2007. Phytoplankton of the western coasts of Baja California in two different seasons in 1998. Scientia Marina 71(4): 735-743.         [ Links ]

Hummert, C., M. Reichelt & B. Luckas. 1997. Automatic HPLC-UV Determination of domoic acid in mussels and algae. Chromatographia 45: 284-288.         [ Links ]

Jeffrey, S. W. & M. Vesk. 1997. Introduction to marine phytoplankton and their pigment signature. In: Jeffrey, S. W., R. F. C. Mantoura & S. W. Wright (Eds.). Phytoplankton Pigments in Oceanography. UNESCO, Paris, pp. 37-84.fr4        [ Links ]

Lange, C. B., F. M. H. Reid & M. Vernet. 1994. Temporal distribution of the potentially toxic diatom Pseudo-nitzschia australis at a coastal site in Southern California. Marine Ecology Progress Series 104: 309-312.         [ Links ]

Lawrence, J. F., C. F. Charbonneau, C. Ménard, M. A. Quilliam & P. G. Sim. 1989. Liquid chromatographic determination of domoic acid in shellfish products using the paralytic shellfish poison extraction procedure of the Association of Official Analytical Chemists. Journal of Chromatography 462: 349-356.         [ Links ]

Lefebvre, K. A., M. W. Silver, S. L. Coale & R. S. Tjeerdema. 2002. Domoic acid in planktivorous fish in relation to toxic Pseudo-nitzschia cell densities. Marine Biology 140: 625-631.         [ Links ]

Lefebvre, K. A., E. R. Frame & P. S. Kendrick. 2012. Domoic acid and fish behavior: A review. Harmful Algae 13: 126-130.         [ Links ]

Lewitus, A. J., R. A. Horner, D. A. Caron, E. García-Mendoza, B. M. Hickey, M. Hunter, D. D. Huppert, R. M. Kudela, G. W. Langlois, J. L. Largier, E. J. Lessard, R. RaLonde, J. E. J. Rensel, P. G. Strutton & V. L. Trainer. 2012. Harmful algal blooms along the North American west coast region: History, trends, causes, and impacts. Harmful Algae 19: 133-159.         [ Links ]

Licea-Durán, S., S. Gómez-Aguirre, R. Cortés-Altamirano & S. Gómez. 1999. Notas sobre algunos florecimientos algales y la presencia de especies tóxicas en cinco localidades del Pacífico mexicano (19961999). In: Tresierra-Aguilar, A. E. & Z., G. Culquichicon-Malpica (Eds.). Libro de resúmenes ampliados, VIII Congreso Latinoamericano sobre Ciencias del Mar, Trujillo, Perú, pp. 335-337.         [ Links ]

López-Cortés, D. J., J. J. Bustillos-Guzmán & I. Gárate-Lizárraga. 2006. Unusual mortality of krill (Crustacea: Euphausiacea) in Bahía de La Paz, Gulf of California. Pacific Science 60 (2): 235-242.         [ Links ]

Núñez-Vázquez, E. J., I. Gárate-Lizárraga, C. J. Band-Schmidt, A. Cordero-Tapia, D. J. López-Cortés, F. E. Hernández-Sandoval, A. Heredia-Tapia, & J. Bustillos-Guzmán. 2011. Impact of harmful algal blooms on wild and cultured animals in the Gulf of California. Journal of Environmental Biology 32: 413-423.         [ Links ]

Obeso-Nieblas, M., B. Shirasago-Germán, J. Gaviño-Rodríguez, E. Pérez-Lezama, H. Obeso-Huerta & A. Jiménez-Illescas. 2008. Variabilidad hidrográfica en Bahía de La Paz, Golfo de California, México (1995-2005). Revista de Biología Marina y Oceanografía 43 (3): 559-567.         [ Links ]

Ochoa, J. L., A. Sierra-Beltrán, A. Cruz-Villacorta & E. Núñez-Vázquez.1996. Domoic acid in Mexico. In: Penney, R. W. (Ed.). Proceedings of the Fifth Canadian Workshop on Harmful Marine Algae. Canadian Technical Report of Fisheries and Aquatic Sciences 2138, St. John's, Newfoundland, Canada, pp. 82-90.         [ Links ]

Ochoa, J. L., A. Sierra-Beltrán, G. Alonso-Colmenares, H. Barradas-Sánchez, A. Cruz-Villacorta, E. Núñez-Vázquez & A. Sánchez-Paz. 1998. Biotoxins in the Pacific coast of Mexico. In: Miraglia M., H. van Egmond, C. Brera & J. Gilbert (Eds.). Mycotoxins and phycotoxins-development in chemistry, toxicology and food safety. International Union of Pure and Applied Chemistry. Printed Alaken, Fort Collins, USA, pp. 441-448.         [ Links ]

Quijano-Scheggia, S., A. Olivos Ortíz, J. E. Gaviño Rodríguez. 2011. Primer reporte de Pseudo-nitzschia brasiliana y P. micropora (Bacillariophyceae) en la Laguna de Cuyutlán, México. Revista de Biología Marina y Oceanografía 46 (2): 189-197.         [ Links ]

Schnetzer, A, P. E. Millar, R. A. Schaffner, B. A. Stauffer, B. H. Jones, S. B. Weisberg, P. M. DiGiacomono, W. M. Berelson & D. A. Caron. 2007. Bloom of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California Bight, 2003-2004. Harmful Algae 6: 372-387.         [ Links ]

SEMARNAT-PROFEPA (Secretaría del Medio Ambiente y Recursos Naturales-Procuraduría Federal de Protección al Ambiente), 1997. Mortandad de mamíferos marinos cuyos cadáveres arribaron a las costas de Sinaloa. Informe Técnico. Distrito Federal, México. 34 p.         [ Links ]

Sierra-Beltrán,A., A. Cruz-Villacorta, S. Lluch-Cota, M. López-Valenzuela, R. Rosiles, J. Cerecero-Gutiérrez & J. L. Ochoa. 1997a. Domoic acid (ASP) implicated in marine animals casualties in the Gulf of California, Mexico. Abstract from 12th World Congress on Animal, Plant and Microbial Toxins-IST. 21-26 September. Cuernavaca, Morelos, México. Instituto de Biotecnología, Universidad Nacional Autónoma de México. 75 p.         [ Links ]

Sierra-Beltrán, A, M. Palafox-Uribe, J. Grajales-Montiel, A. Cruz-Villacorta & J. L. Ochoa. 1997b. Sea bird mortality at Cabo San Lucas, México: Evidence that toxic diatom blooms are spreading. Toxicon 35 (3): 447-454.         [ Links ]

Sierra-Beltrán, A., A, Cruz, E. Nuñez-Vázquez, L. M. Del Villar, J. Cerecero & J. L. Ochoa. 1998. An overview of the marine food poisoning in Mexico. Toxicon 36 (9): 1493-1502.         [ Links ]

Sierra-Beltrán, A., J. L. Ochoa, S. Lluch-Cota, A. Cruz-Villacorta, R. Rosiles, M. López-Valenzuela, L. M. Del Villar-Ponce & J. Cerecero-Gutiérrez. 1999. Pseudo-nitzschia australis (Frengueli), responsable de la mortandad de aves y mamíferos marinos en el Alto Golfo de California, México, en 1997, 1999. Tresierra-Aguilar, A. E. & Z. G.Culquichicón-Malpica (Eds.). VIII COLACMAR (Latinoamerican Congress on Marine Sciences) Trujillo, Perú, pp. 17-21.         [ Links ]

Sierra-Beltrán, A., R. Cortés-Altamirano, J. P. Gallo-Reynoso, S. Licea & J. Egido-Villareal. 2005. Is Pseudo-nitzschia pseudodelicatissima toxin the principal cause of sardines, dolphins, sea lions and pelicans mortality in 2004 in Mexico? Harmful Algae News 29: 6-8.         [ Links ]

Smayda, T. 2006. Harmful algal bloom communities in Scottish coastal waters: Relationship to fish farming and regional comparisons-A Review. Diatom blooms and fish mortality. Natural Scotland, Scottish Executive Environment Group, Scotland: pp. 97-99. Available online at: http://www.scotland.gov.uk/Publications/2006/02/03095327/0        [ Links ]

Strickland, J. D. H. & T. R. Parsons. 1972. A practical handbook of seawater analysis, 2nd ed. Fisheries Research Board Canada Bulletin, Ottawa, Canada. 310 p.         [ Links ]

Trainer, V. L., M. L. Wells, W. P. Cochlan, C. G. Trick, B. D. Bill, K. A. Baugh, B. F. Beall, J. Herndon & N. Lundholm. 2009. An ecological study of a massive bloom of toxigenic Pseudo-nitzschia cuspidata off the Washington State coast. Limnology and Oceanography 54 (5): 1461-1474.         [ Links ]

Trainer, V. L., S. S. Bates, N. Lundholm, A. E. Thessen, N. G Adams & W. P. Cochlan. 2012. Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health. Harmful Algae 14: 271-300.         [ Links ]

Utermöhl, H. 1958. Zur Vervollkommnung der quantitativen phytoplankton methodik. Mitteilungen Internationale Vereinigung für theoretische und angewandte Limnologie 9: 1-38.         [ Links ]

Vera-Avila, L. E., D. Y. Martín-Pérez & R. Covarrubias-Herrera. 2011. Trace level determination of domoic acid in seawater by off-line/on-line solid-phase extraction coupled to HPLC-UV. Journal of Mexican Chemistry Society 55 (2): 65-71.         [ Links ]

Vidussi, F., H. Claustre, J. J. Bustillos-Guzmán, C. Cailleau & J. C. Marty. 1996. Determination of chlorophylls and carotenoids of marine phytoplankton: Separation of chlorophyll a from divinyl-chlorophyl a and zeaxanthin from lutein. Journal of Plankton Research 18: 2377-2382.         [ Links ]