Harmful algal blooms of the southern Benguela Current: a review and appraisal of monitoring from 1989 to 1997

Pitcher, GC; Calder, Dale R.

doi:10.2989/025776100784125681

Cited by 121 publications

(98 citation statements)

References 21 publications

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“…Interestingly, a similar productive upwelling system in South Africa (the Benguela Current) has experienced sardine (S. sagax) mortalities related to A. catenella, and the safety limit for Wsh harvesting used there is 80 g STXeq 100 g ¡1 of viscera (Pitcher and Calder 2000). In at least one mortality event in that region, sardine stomach contents contained between 60,000 and 80,000 A. catenella cells and toxin levels just exceeded the harvestable limit, leading the authors to conclude that these Wsh are highly sensitive to PSTs (Pitcher and Calder 2000). In this study, we detected PSTs over 80 g STXeq 100 g ¡1 only once in sardines (250 g STXeq 100 g ¡1 ).…”

Section: Discussionmentioning

confidence: 99%

“…These Wndings, along with the knowledge that PSTs have been detected in many of these animals in other regions, e.g. zooplankton (Turner et al 2000;Doucette et al 2005), crabs (Shumway 1995), planktivorous Wsh (White 1977(White , 1980Pitcher and Calder 2000) and whales (Geraci et al 1989), suggests that PSTs may also be present in California food webs to a further degree than we are currently aware of.…”

Section: Introductionmentioning

confidence: 99%

“…Although shellWsh appear to be the most serious vectors of PSTs to humans, the accumulation of these toxins in other Wlter-feeding organisms and the subsequent trophic transfer to higher-level predators is a global phenomenon that has resulted in severe mortality events involving WnWsh, marine mammals and seabirds (McKernan and ScheVer 1942;White 1977White , 1980Hortsman 1981;Geraci et al 1989;Montoya et al 1996;Pitcher and Calder 2000). Zooplankton and planktivorous Wsh are a primary vector of PSTs in many ecosystems, and, as with bivalves, can provide a direct link between the toxic cells and higher trophic levels (Teegarden and Cembella 1996;Pitcher and Calder 2000;Turner et al 2000;Durbin et al 2002;Doucette et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Zooplankton and planktivorous Wsh are a primary vector of PSTs in many ecosystems, and, as with bivalves, can provide a direct link between the toxic cells and higher trophic levels (Teegarden and Cembella 1996;Pitcher and Calder 2000;Turner et al 2000;Durbin et al 2002;Doucette et al 2005). Several reports indicate zooplankton and/or planktivorous Wsh serve as an important step in the transfer of PSTs involved in kills of Argentine mackerel (Mianzan et al 1997), Atlantic herring (White 1977;1980), Atlantic salmon (Sephton et al 2007) and even humpback whales in the Gulf of Maine (Geraci et al 1989).…”

Section: Introductionmentioning

confidence: 99%

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Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA

2009

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The central California coast is a highly productive, biodiverse region that is frequently aVected by the toxin-producing dinoXagellate Alexandrium catenella. Despite the consistent presence of A. catenella along our coast, very little is known about the movement of its toxins through local marine food webs. In the present study, we investigated 13 species of commercial WnWsh and rock crabs harvested in Monterey Bay, California for the presence of paralytic shellWsh toxins (PSTs) and compared them to the presence of A. catenella and PSTs in sentinel shellWsh over a 3-year period.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA

2009

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“…390 µgC l -1 ) values; to avoid overlapping of circles, they represent 50% of their original size; as such, the absence of a bubble does not necessarily mean no occurrence, but that the relative abundance is low. ) of potentially HAB organisms (Hallegraeff, 1995;Pitcher and Calder, 2000;Smayda, 2000) from May to September (2001) Ceratium spp., Gonyaulax spp., and Scrippsiella spp., amongst other organisms (Pitcher and Calder, 2000;Smayda, 2000). These blooms, although nontoxic, are undesirable because they may cause fish and invertebrate killings due to oxygen depletion, following the decay of the blooms.…”

Section: Potentially Hab Organismsmentioning

confidence: 99%

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

Loureiro¹,

Newton²,

Icely³

2005

Sci. Mar.

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SUMMARY: Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal) during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling centre off Cabo S. Vicente, and 2 km west of an offshore installation for bivalve aquaculture. Three major periods were distinguished according to sea surface temperature (SST): period 1 (P1; May and June), characterised by high temperature values (17.0±1.8ºC); period 2 (P2; July), characterised by lower temperatures (14.6±0.3ºC), identified as an upwelling-blooming stage; and period 3 (P3; August), characterised by a high temperature pattern (16.25±1.14ºC). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. and Pseudo-nitzschia spp. were the major taxa contributing to the dissimilarities between P2 (July) and the other periods. In July (P2), the average gross production (GP; 52.5±12.3 µM O 2 d -1 ) and net community production (NCP; 46.9±15.3 µM O 2 d -1 ) peaked with the maximal concentrations of diatom-chl a. Dark community respiration (DCR) remained low and more constant throughout (4.6±3.6 µM O 2 d -1 ). The plankton assemblage was dominated by diatoms throughout the survey. Physical events were the primary factors determining the microplankton structure and distribution at this location.Keywords: production, respiration, microplankton community, Iberian Peninsula, Cabo S. Vicente. RESUMEN: COMPOSICIÓN DEL MICROPLANCTON, PRODUCCIÓN Y DINÁMICA DEL AFLORAMIENTO EN SAGRES (SUROESTE DE PORTUGAL) DURANTE EL VERANO DE2001. -La comunidad microplanctónica, la producción y la respiración, fueron estudiadas en Sagres (SE Portugal) durante la época de afloramiento, de Mayo a Septiembre 2001, junto con parámetros físicos y químicos. La estación de muestreo está a 5 km Este del centro de afloramiento del Cabo S. Vicente, y a 2 km Oeste de una instalación para el cultivo de bivalvos. Según los patrones de la temperatura del agua de superficie (SST) se diferenciaron tres periodos: periodo 1 (P1; Mayo y Junio), caracterizado por temperaturas altas (17.0±1.8ºC); periodo 2 (P2; Julio), caracterizado por temperaturas más bajas (14.6±0.3ºC), identificado como un estado de -afloramiento; periodo 3 (P3; Agosto), caracterizado por un patrón de temperaturas altas (16.25±1.14ºC). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. y Pseudo-nitzschia spp., fueron los principales grupos que contribuyeron a la diferenciación entre P2 (Julio) y el resto de periodos. Durante Julio (P2) la media de producción primaria bruta (GP; 52.5±12. ) alcanzaron sus valores máximos, simultáneamente con el pico de diatomeas-chl a. La respiración de la comunidad en la oscuridad (DCR) permaneció baja y constante durante el muestreo (4.6±3.6 µM O 2 d -1 ). La comunidad estaba dominada por diatomeas durante todo el muestreo. Los eventos físicos fueron el factor principal en la determinación de la estructura de la comunidad microplanctónica en esta localidad.

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A critically endangered estuarine limpet’s only two populations are genomically and morphologically distinct

de Coito,

Emami‐Khoyi,

Hedderson

et al. 2023

Aquatic Conservation

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Seagrass habitats are declining worldwide, placing several seagrass‐associated animals at risk of extinction. The Critically Endangered limpet Siphonaria compressa is one of the rarest molluscs in Africa, and has been reported from only two disjunctive lagoons in South Africa. Being a highly specialized grazer that lives exclusively on the narrow blades of Cape eelgrass, Zostera capensis, which is itself listed as Endangered in the South African Red List and has decreased in abundance, conservation initiatives are urgently needed to ensure the long‐term survival of S. compressa. Molecular data (sequence data from the mitochondrial genome and single nucleotide polymorphism data of the nuclear genome) and morphological data were analysed to determine whether the two populations are conspecific, with implications for whether translocation between localities could be a viable management strategy to restore either population in the event of a collapse, or to maintain the genetic diversity of each population. Strong evidence emerged for the distinctness of the two populations, including a lack of shared mtDNA haplotypes that indicate an absence of contemporary gene flow, a divergence time that dates to the late Pleistocene, and a number of morphological characters that distinguish their shells. These findings indicate that the two populations are distinct cryptic subspecies. As the two populations occur in different temperature‐defined marine biogeographical regions, they are probably adapted to different thermal environments. Translocations are not recommended, as this management strategy has considerable potential to result in outbreeding depression and exacerbate the extinction risk. Instead, each population should be managed separately, and several alternative conservation measures are discussed, including the protection and restoration of seagrass beds.

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Harmful algal blooms of the southern Benguela Current: a review and appraisal of monitoring from 1989 to 1997

Cited by 121 publications

References 21 publications

Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA

Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA

Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001

A critically endangered estuarine limpet’s only two populations are genomically and morphologically distinct

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