Environ Monit Assess
(2021) 193:333
1 3
333
Page 2 of 12
The toxicity of the Ostreopsis genus has been attributed to the synthesis of palytoxin (PLTX)-like compounds that include isobaric palytoxin and ovatoxins
(Açaf, 2018). Palytoxin is one of the most dangerous
marine toxins known (Patocka et al., 2018). It is known
to be strong Na+/K+ ATPase pump inhibitors (Poli
et al., 2018). Ostreopsis blooms threaten human health
and marine life and can be a source of several economic
concerns. It has an impact on tourism (beach closures)
(Tichadou et al., 2010), commercial fisheries, and aquaculture (Privitera et al., 2012; Rhodes & Munday, 2016).
Also, the accumulation of this microalga strongly disrupts the food web (Boisnoir et al., 2020).
The means of Ostreopsis sp. intoxication are the
physical contact with contaminated water (bathing activities) (Vila et al., 2012) or inhalation of
the marine aerosol containing PLTX and/or cellular debris of Ostreopsis sp. (Ciminiello et al, 2014;
Zingone et al., 2020), as well as the consumption of
contaminated seafood (Aligizaki et al., 2011) since
palytoxin-like compounds have been found in fish,
echinoderms, gastropods, crustaceans, and cephalopods (Amzil et al., 2012; Biré et al., 2013). One of
the most intense exposure to Ostreopsis sp. bloom
in Algeria occurred in summer 2009, resulting in the
intoxication of 400 people and the hospitalization of
40 cases (Illoul et al., 2012). Usually, toxic effects are
limited to skin irritation and flu-like symptoms such
as fever, cough, conjunctivitis, and respiratory distress (Tichadou et al., 2010; Vila et al., 2016).
The toxicity of Ostreopsis sp. is not limited to
humans. Recently, several studies showed the extent
of its toxicity on various marine organisms, both
invertebrates and vertebrates (Pagliara & Caroppo,
2012; Blanfune et al., 2012; Guidi-Guilvard et al.,
2012; Gorbi et al.., 2013; Mcnamee et al., 2016;
Neves et al., 2018; Cen et al., 2019; Pavaux et al.,
2020). However, the mechanism involved in the
massive mortalities of some marine organisms is
unknown; it can be due to Ostreopsis produced toxins,
oxygen limitation, or a combination of the blooms
with a high temperature (Lassudrie et al., 2020).
In the Mediterranean Sea, the genus Ostreopsis has
several species including Ostreopsis. cf. ovata (Cohu
et al., 2011), Ostreopsis. cf. siamensis (Ciminiello
et al., 2013), and the recently described Ostreopsis.
cf. fattorussoi (Accoroni et al., 2016). Due to the high
morphological similarity between Mediterranean
Ostreopsis species, it is extremely difficult to identify
the differences by optical microscopy. Therefore,
Ostreopsis sp. was adopted in this manuscript.
Understanding the spatio-temporal variability of
phytoplankton in aquaculture zones is necessary for the
prevention and/or prediction of harmful algal bloom
events (Artigas et al., 2014). Many studies were carried
out to understand the phytoplankton structure and their
relationship with environmental parameters in typical
mariculture areas (Busch et al., 2016; Challouf et al.,
2017; Qiao et al., 2020). However, none of them have
revealed the presence of the genus Ostreopsis in an
inland Gilthead seabream farm.
The purpose of the samples was the analysis of phytoplankton diversity. In the summer 2016, breathing difficulties and skin irritation among workers and visitors
(18 persons) inside the Gilthead sea bream farm were
stated, suspecting a particular kind of unicellular alga,
Ostreopsis sp. as a causative agent. But this has not
been confirmed, and therefore, this study aims to show
the environmental parameters related to the dynamics
of the genus Ostreopsis in the inland fish farm.
Material and methods
Study site and sampling
Water samples for estimating abundances of phytoplankton cells were collected from inland Gilthead seabream
farm in Northwest Algeria (35°32.23′N/01°12.07′W),
in the Southwestern Mediterranean sea (Fig. 1). The
farm covers an area of 3.5 ha, and it has an open water
circulation system, with an average production of 300
tons year
−1
. Gilthead seabream is farmed in a concrete raceway (Lounas et al., 2021). Seawater does not
undergo any treatment either at the input or at the output. Sampling was performed fortnightly during the
2016 and 2017 summer (June to September), using plastic bottles (from 250 mL to 1 L). Three sampling stations were chosen: St.1 “Input water” and St.2 “Output
water”, whose distance between one another is equal
to 300 m, and St.3 “fish pond”, which was used only to
check the presence or not of Ostreopsis cell’s.
The seawater samples for counting Ostreopsis cells
were fixed with a 1–2% Lugol’s solution. All samples
were kept in the dark at 4 °C and transported to the laboratory for further analysis. Temperature and salinity
were determined in situ by the use of a multiparameter
(2021) 193:333
1 3
333
Page 2 of 12
The toxicity of the Ostreopsis genus has been attributed to the synthesis of palytoxin (PLTX)-like compounds that include isobaric palytoxin and ovatoxins
(Açaf, 2018). Palytoxin is one of the most dangerous
marine toxins known (Patocka et al., 2018). It is known
to be strong Na+/K+ ATPase pump inhibitors (Poli
et al., 2018). Ostreopsis blooms threaten human health
and marine life and can be a source of several economic
concerns. It has an impact on tourism (beach closures)
(Tichadou et al., 2010), commercial fisheries, and aquaculture (Privitera et al., 2012; Rhodes & Munday, 2016).
Also, the accumulation of this microalga strongly disrupts the food web (Boisnoir et al., 2020).
The means of Ostreopsis sp. intoxication are the
physical contact with contaminated water (bathing activities) (Vila et al., 2012) or inhalation of
the marine aerosol containing PLTX and/or cellular debris of Ostreopsis sp. (Ciminiello et al, 2014;
Zingone et al., 2020), as well as the consumption of
contaminated seafood (Aligizaki et al., 2011) since
palytoxin-like compounds have been found in fish,
echinoderms, gastropods, crustaceans, and cephalopods (Amzil et al., 2012; Biré et al., 2013). One of
the most intense exposure to Ostreopsis sp. bloom
in Algeria occurred in summer 2009, resulting in the
intoxication of 400 people and the hospitalization of
40 cases (Illoul et al., 2012). Usually, toxic effects are
limited to skin irritation and flu-like symptoms such
as fever, cough, conjunctivitis, and respiratory distress (Tichadou et al., 2010; Vila et al., 2016).
The toxicity of Ostreopsis sp. is not limited to
humans. Recently, several studies showed the extent
of its toxicity on various marine organisms, both
invertebrates and vertebrates (Pagliara & Caroppo,
2012; Blanfune et al., 2012; Guidi-Guilvard et al.,
2012; Gorbi et al.., 2013; Mcnamee et al., 2016;
Neves et al., 2018; Cen et al., 2019; Pavaux et al.,
2020). However, the mechanism involved in the
massive mortalities of some marine organisms is
unknown; it can be due to Ostreopsis produced toxins,
oxygen limitation, or a combination of the blooms
with a high temperature (Lassudrie et al., 2020).
In the Mediterranean Sea, the genus Ostreopsis has
several species including Ostreopsis. cf. ovata (Cohu
et al., 2011), Ostreopsis. cf. siamensis (Ciminiello
et al., 2013), and the recently described Ostreopsis.
cf. fattorussoi (Accoroni et al., 2016). Due to the high
morphological similarity between Mediterranean
Ostreopsis species, it is extremely difficult to identify
the differences by optical microscopy. Therefore,
Ostreopsis sp. was adopted in this manuscript.
Understanding the spatio-temporal variability of
phytoplankton in aquaculture zones is necessary for the
prevention and/or prediction of harmful algal bloom
events (Artigas et al., 2014). Many studies were carried
out to understand the phytoplankton structure and their
relationship with environmental parameters in typical
mariculture areas (Busch et al., 2016; Challouf et al.,
2017; Qiao et al., 2020). However, none of them have
revealed the presence of the genus Ostreopsis in an
inland Gilthead seabream farm.
The purpose of the samples was the analysis of phytoplankton diversity. In the summer 2016, breathing difficulties and skin irritation among workers and visitors
(18 persons) inside the Gilthead sea bream farm were
stated, suspecting a particular kind of unicellular alga,
Ostreopsis sp. as a causative agent. But this has not
been confirmed, and therefore, this study aims to show
the environmental parameters related to the dynamics
of the genus Ostreopsis in the inland fish farm.
Material and methods
Study site and sampling
Water samples for estimating abundances of phytoplankton cells were collected from inland Gilthead seabream
farm in Northwest Algeria (35°32.23′N/01°12.07′W),
in the Southwestern Mediterranean sea (Fig. 1). The
farm covers an area of 3.5 ha, and it has an open water
circulation system, with an average production of 300
tons year
−1
. Gilthead seabream is farmed in a concrete raceway (Lounas et al., 2021). Seawater does not
undergo any treatment either at the input or at the output. Sampling was performed fortnightly during the
2016 and 2017 summer (June to September), using plastic bottles (from 250 mL to 1 L). Three sampling stations were chosen: St.1 “Input water” and St.2 “Output
water”, whose distance between one another is equal
to 300 m, and St.3 “fish pond”, which was used only to
check the presence or not of Ostreopsis cell’s.
The seawater samples for counting Ostreopsis cells
were fixed with a 1–2% Lugol’s solution. All samples
were kept in the dark at 4 °C and transported to the laboratory for further analysis. Temperature and salinity
were determined in situ by the use of a multiparameter