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Causes of Outbreak in M'Diq Beach, Pelagia noctiluca
Northwest Moroccan Mediterranean Coastline
Indian Journal of Ecology (2021) 48(2): 519-523
Manuscript Number: 3245
NAAS Rating: 5.79
Abstract: The M'Diq beach has seen a successive outbreak's of starting in 2011. During the summer season, which is also Pelagia noctiluca
known as the blooming and stranding's jellyfish season has severe impacts on regional activities. For this reason, this research aimed at
documenting the mean causes of outbreaks on our coastline. As a result, the simple linear tests shows that outbreaks P. noctiluca P. noctiluca
have a very significant linear relationship and are positively correlatedto sea surface temperature with P= 0.0079 with y = 3.5254x - 59.616, R²
= 0.2062, sea salinity P= 0.0029 with y =14.741x - 507.54, R² = 0.2517 and waves high P= 0.000000002 with y = 20.473x - 4.4583, R² = 0.6893.
Moreover, the blooms of jellyfish along with the production of Pelagic fish and whitefish were respectively and share a strong correlation with
P= 0.000001936, with y = -0.0079x + 40.881, R² = 0.5063 for Pelagic fish and y = -0.0323x + 55.431, R² = 0.3008 for whitefish production.
Keywords: Jelly fish, Blooms, Fisheries productions, Moroccan Mediterranean northwest coastlinePelagia noctiluca,
Majda Aouititen, Aravinda Ravibhanu Mohammed Mrhraoui and Xiaofeng Luan
1, 2
School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
1Department of Research & Innovation-Eco Astronomy Inc, Colombo, Sri Lanka
2National Institute of Fisheries Research Tangier-M'Diq-Morocco
E-mail: majda_578@yahoo.fr
It is undeniable that long-term climatic change will
influence the increase of jellyfish outbreaks, as weather
factors such as temperature and precipitation change (Hecq
et al 2009, Aouititen et al 2019). Some theories mentioned
the impact of some hormone pollutants discharged into the
ocean; notably, estradiol contained in drugs for the treatment
of menopause and contraceptives, themselves included in
human urine as well as the insecticide impacts (Dhawan et al
2012), case study observed of the insecticides toxicity on the
marine crustacean the brine shrimp (Nwokwu Gilbert
Nwogboduhu 2017); that would result in mutations in fish.
Although in tiny quantities, these potent hormones can
influence the sexual development of fish, the loss of male fish
reduces breeding opportunities and can exacerbate
declining fish populations leading to a proliferation of jellyfish.
Pelagia noctiluca, because of their capacity for budding and
asexuality, do not fear these hormones. If global warming
persists in the years to come, jellyfish populations will likely
increase dramatically in all the world's seas and oceans.
Increasing jellyfish populations will directly damage fish
populations through predation and competition. The decline
of fish numbers risks becoming a vicious circle, although the
port of M'Diq is an excellent sardine port, in 2011 there was an
alarming indication of a real depletion of the stock. The
economic contribution of this type of fishing is becoming
increasingly small.
Moreover, the massive appearances of the scyphozoan
jellyfish are becoming more frequent in the P. noctiluca
western Mediterranean. The jellyfish stranding is interfering
with fishing by plugging fishnets and competing with fish for
food (Kogovšek et al 2010, Daly et al 2010). According to
some observations, "jellyfish can also kill fish and their larvae
in aquaculture pens, or clog the pipelines of desalting and
power plants" ( ). Another problem Malačič et al 2007
observed during surveys where fishers would cast their
fishing nets, a large number of jellyfish can become ensnared
with the fish become pulverized and contaminated the edible
fish, reducing the market value of the catch. is a P. noctiluca
crucial "non-selective planktonic predator feeding on almost
all types of zooplankton and ichthyoplankton" (Daly et al
2010, Rosa et al 2013). Many types of fish, such as reef fish
species, as well as pelagic fish species eating ephyrae and
small individuals, compete for the same zooplankton prey as
jellyfish (Graham 2001, ). As argued Purcell et al 2001 2007
here, the declination of those fishes will open up ecological
niches for jellyfish proliferation ( 2004,Lynam Purcell et al
2007). The objective of this research is to understand the
causes of outbreaks observed since 2011 Pelagia noctiluca
in the Moroccan Mediterranean coastal. Besides, the
importance of this research is to document and to highlight as
well the severe impact that jellyfish outbreaks have on
fisheries production.
MATERIAL AND METHODS
Study area: M'Diq is known as a seaside city, located at the
geographical coordinates 35° 41'N, and 5° 19 '31 W. Fishing
and summer tourism are the mean economic resources for
the local population. M'Diq covers an area of 480 hectares, of
which 153 hectares are urbanized. The city is located 7 km
from Tetouan city, and it is bounded on the east by the
Mediterranean Sea (Aouititen et al 2019). The selection of
this area to conduct the research is due to the critical
numbers of outbreaks recorded. The existence of P. noctiluca
permanent surface currents characterizes the marine
hydrology in this area, and continuous flow from west to the
east brings Atlantic waters into the Mediterranean,
compensating for losses by evaporation and which result in
heavy salinization. The winds are sometimes violent and play
a role in the disturbance of these surface currents, creating
currents opposite to those described above. The tides are of
low amplitude, with the highest reaching barely two meters,
and they generally remain poorly perceived because of the
steep slope of the shoreline . (Dakki 2004)
Sampling strategy: P. noctilucaFrom 2011 to 2017, was
collected daily during each blooming season to conduct
biometric measurements (Fig. 1). The selected transect in
M'Diq was between the low tide and high tide limit. The
transect start and endpoints were recorded and described as
follows: "start: 35.683160 N, -5.319175 W; 35.698070 N, -
5.328777 W; length: 963m". The variation in the production of
pelagic and whitefish data in the M'Diq port was collected
from the Moroccan national office of fisheries. The waves
high were recorded from Copernicus online database. Sea
surface temperature, as well as sea surface salinity, was
recorded in situ (independent points) for each survey
(Aouititen et al 2019). Both of these parameters have been
recorded from June 2011 until December 2017 during each
jellyfish stranding day, and a monthly average used for
correlation analyses with jellyfish abundance. The
calculation of jellyfish stranded density per square meter was
performed by using a quadrate method (Aouititen et al 2019).
Fig. 1. The geographical location of our study area
Source: Google Map
Cluster analysis: The data obtained from the samples were
statistically analyzed using SPSS 25 and Microsoft Office
Excel 2010. Simple linear regression and ANOVA analysis
was used to investigate whether there is a relationship
between the quantitative variable, which is sea surface
salinity, temperature, waves high and for both Pelagic fish
and Whitefish production in the M'Diq port and the changes of
P. noctiluca density during the blooming seasons to
understand which type of correlation they share.
RESULTS AND DISCUSSION
The simple linear regression analysis proved that there
is a strong significant relationship between the blooms of P.
noctiluca collected and the high sea surface temperature
recorded since 2011 till 2017 (Table 1). The P-value were P <
0.05, P= 0.007937422. Moreover, that these two parameters
are correlated positively, which means when the sea surface
temperature rises, then the outbreaks of our jellyfish will
increase as well, with y = 3.5254x - 59.616, R² = 0.2062 (Fig.
2).
Scientists proved that sea temperature could influence
jellyfish life cycles and its reproductive process (Purcell et al
2007, Boero et al 2008 Seawater temperature, together ).
with available resources of nutrients, were essential drivers
of gonads development (Ben-David-Zaslow and Benayahu
1999). The increase in temperature is considered to be a key
factor for the successful reproductive processes of P.
noctiluca.
Sea Surface Salinity (SSS) and jellyfish blooms: In Table
1, the simple linear regression analysis along with ANOVA
test has proved as well that there is a very significant
relationship between the blooms of Pelagia noctiluca
collected and the sea surface salinity recorded from 2011 till
2017 as it showed the P-value found to be P < 0.05, P=
0.002931034. Besides, we have found that these parameters
correlated positively, which mean when the sea surface
salinity increase then the blooms of our jellyfish will increase
as well; with y =14.741x - 507.54, R² = 0.2517 (Fig. 3).
Between 1976 until 1983, a research conducted by Tegaccia
(1983) mentioned as well that the highest densities of P.
noctiluca in the Adriatic Sea were recorded with high salinity
and low nutrients.
Sea waves high and jellyfish blooms: After testing the
relationship between Sea waves high and jellyfish blooms
density using a simple linear regression analysis along with
ANOVA test (Table 1) we have found that there is a significant
strong relationship; as it showed the P-value was found to be
P < 0.05, P= 0.0000000023. In fact, these parameters are
found to share a positive correlation, which means when the
waves start to be higher as results, the blooms of Pelagia
520 Majda Aouititen, Aravinda Ravibhanu, Mohammed Mrhraoui and Xiaofeng Luan
0
10
20
30
40
50
60
15 17 19 21 23 25 27
Sst (°C)
Fig. 2. Simple linear regression analysis of sea surface
temperature (SST) and jellyfish blooms density
0
10
20
30
40
50
60
34.5 35 35.5 36 36.5 37 37.5
SSS (Psu)
Fig. 3. Simple linear regression analysis of Sea Surface
Salinity (SSS) and jellyfish blooms density
0
10
20
30
40
50
60
0 1 2 3
Wave height (m)
Fig. 4. Simple linear regression analysis of Sea waves high
and jellyfish blooms density
Regression statistics Correlation between SST &
jellyfish blooms density
correlation between SSS &
jellyfish blooms density
Correlation between Sea waves high &
jellyfish blooms density
Multiple R 0.45412688 0.50173889 0.830223056
R Square 0.20623122 0.25174192 0.689270323
Adjusted R Square 0.18062578 0.22760456 0.679246785
Standard error 14.6319741 14.2063211 9.154766775
Observations 33 33 33
SS 1724.360006 2104.888361 5763.192295
MS 1724.36 2104.888 5763.1923
F 8.054194 10.42956 68.76517
Significance F 0.007937422 0.002931034 2.2895E-09
Table 1. Simple linear regression and ANOVA analysis of the correlation between Sea waves high and jellyfish blooms density
noctiluca will increase in our shoreline; with y = 20.473x -
4.4583, R² = 0.6893 (Fig. 4).
Aouititen et al (2019) concluded that waves high as well
as Est wind could lead to the prediction of jellyfish stranding in
the Moroccan Northwest Mediterranean coastline.
Pelagic fish and Whitefish production and jellyfish
blooms: There is a significant relationship, as it showed the
P-value found to be P < 0.05, P= 0.000001936 (Table 2).
However, these parameters were found to be negatively
correlated, which mean when the Pelagic fish and whitefish
production start to decrease then the blooms of P. noctiluca
will increase in our area of study; with y = -0.0079x + 40.881,
R² = 0.5063 for Pelagic fish production and y = -0.0323x +
55.431, R² = 0.3008 for whitefish production and blooms of
our jellyfish (Fig. 5).
Outbreaks of were reported in 2007 to cause P. noctiluca
mortalities of farmed fish in northeast Ireland and on the
Scottish west coast (Doyle et al 2008). The outbreaks of P.
noctiluca appear to be associated with affecting fish and
521Causes of Pelagia noctiluca Outbreak
0
5
10
15
20
25
30
35
1500 2500 3500 4500 5500
Weight per ton of Pelagic
fish in M'diq port
0
5
10
15
20
25
30
35
650 850 1050 1250 1450
Weight per ton of White
fish in M'diq port
Fig. 5. Simple linear regression correlation between weight
per ton of Pelagic and Whitefish with Pelagia
noctiluca blooms density
ANOVA
SUMMARY
Groups Count Sum Average Variance
Pelagia noctiluca emalesf 7 127.339 18.19129 173.119256
Pelagia noctiluca alesm 7 20114 2873.429 1405746.29
Pelagia noctiluca uvenilej 7 8061 1151.571 49790.619
Source of ariationv SS df MS F P-value F crit
Between roupsg 28937353 2 14468676 29.8177715 1.93601E-06 3.554557146
Table 2 . ANOVA analysis between Pelagic fish and Whitefish production with jellyfish blooms density
Fig. 6. Pelagia noctiluca trapping and in the process of
swallowing a small fish
zooplankton abundance by preying on fish larvae and
competing for nutrients (Purcell 2001, Lynam et al 2005). P.
noctiluca is an important planktonic predator of fish larvae so
they can affect fish larval abundance (Fig. 6) (Daskalov et al
2007, Purcell et al 2007).
CONCLUSION
In this research study, we found that sea surface
temperature with P= 0.007937422, sea salinity P=
0.002931034 as well as waves high P= 0.0000000023
positively correlated to outbreaks on our Pelagia noctiluca
area of study; those parameters are the principal causes which
lead to the blooms of jellyfish along our Moroccan
Mediterranean northwest coastal. Apart from this, the
production of Pelagic fish and whitefish was recorded to have
a negative correlation with jellyfish stranding, and it was found
to be very significant P= 0.000001936, which means when the
production of Pelagic fish and whitefish decrease, we are
going to observer significant outbreaks of . As Pelagia noctiluca
a consequence, we predicate not only to observe consecutive
long blooming seasons but as well we may document a long-
term decrease in marine stocks of fish in our area.
CONTRIBUTION
We declare that Ms. Majda AOUITITEN has collected,
analyzed the data, and wrote the paper. Dr. Mohammed
MRHRAOUI provides us with a laboratory where we
conducted some of our analysis and Dr. Aravinda
RAVIBHANU as well as Pr. Dr. Xiaofeng LUAN reviewed the
manuscript. We would like to address our sincere appreciation
for all the motivation and support we've received from Mrs.
Jamila Semlal.
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Received 26 October, 2020; Accepted 25 December, 2020
523Causes of Pelagia noctiluca Outbreak
