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RECRUITMENT OF CIRRIPEDS AFTER PRESTIGE OIL SPILL
Milagros PENELA-ARENAZ*, Gonzalo MACHO, Esther PÉREZ-FERNÁNDEZ and Elsa VÁZQUEZ
Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo
INTRODUCTION
MATERIAL AND METHODS
The most affected habitats by the Prestige oil spill are the benthic
ecosystems, which have a huge biodiversity. Besides the inmediate impact, that
is shown by an increase of the mortality rates by asphyxia and oil toxicity (e.g.
Sanders et al., 1980), the chronic or sublethal effects can be as desvastating as
the lethal ones, since they can produce a gradual change in the specific
composition, abundance and diversity of the communities that can persist during
years (Kennish, 1997).
One of the most important sublethal effects of an oil spill is a change in
recruitment patterns, which can be important as an influence on the community
structure of rocky shores (e.g. Roberts et al., 1991). Recruitment is the process
that establishes the patterns of abundance and distribution, while factors such as
competition, predation, facilitation or disturbance modify these patterns (Menge,
2000).
The specific objetive of this study is to determine if there are differences in
the recruitment patterns of three species of barnacles (Crustacea Cirripedia),
Chthamalus montagui Southward, Balanus perforatus Bruguiére and Pollicipes
pollicipes Gmelin, in four localities with different affectation level by the Prestige
oil spill.
The recruitment of the intertidal cirripeds Chthamalus montagui, Balanus perforatus and
Pollicipes pollicipes was studied at four locations (Segaño, Cabo Home, Couso and
Caldebarcos) with different affectation level by the Prestige oil spill from February 2004 to
February 2005. Caldebarcos was the heaviest oiled location, followed by Couso. Cabo
Home was lightly affected and Segaño was chosen as the control site since no
hydrocarbons from Prestige were detected.
To study the recruitment of C. montagui and B. perforatus, fifteen 32 cm2 plates were
placed at each site (five in each mesolitoral level). These artificial substrata were collected
and replaced by new ones with a monthly or fortnightly periodicity. In the case of P.
pollicipes, seventy adult individuals were collected with the same periodicity to determine the
percentage of adults that presented, at least, a recruit in the peduncle.
Segaño
Caldebarcos
Couso
Cabo Home
Plates used to study the recruitment of C. montagui and B. perforatus.
Map showing study sites
RESULTS AND DISCUSSION
0
mar
apr
may
jun
jul
aug
sep
oct
nov
dec
jan
feb
0
mar
mar
(The heaviest oiled
location)
apr
may
jun
300
140
250
120
200
150
100
50
may
jun
jul
aug
sep
oct
nov dec
jan
feb
feb
mar
40
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
Month (2004-2005)
140
120
Mean number (with se bars)
Mean number (with se bars)
jan
60
mar
250
200
150
100
50
100
80
60
40
20
0
0
mar apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
mar
apr
may
jun
Month (2004-2005)
jul
aug
sep
oct
nov dec
jan
feb mar
Month (2004-2005)
140
300
120
Mean number (with se bars)
250
Mean number (with se bars)
nov dec
80
mar
300
(Lightly oiled
location)
oct
100
Month (2004-2005)
Cabo Home
sep
0
mar apr
(Heavy oiled
location)
aug
20
0
Couso
jul
Month (2004-2005)
Mean number (with se bars)
Caldebarcos
Mean number (with se bars)
Month (2004-2005)
200
150
100
50
100
80
60
40
20
0
0
mar apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
Month (2004-2005)
Average number (±S.E.) of C.
montagui recruits per plate
throughout the sampling period at the
upper (----), middle (----) and lower
(----) mesolitoral.
mar
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb mar
Month (2004-2005)
Average number (±S.E.) of B.
perforatus recruits per plate
throughout the sampling period at the
upper (----), middle (----) and lower
(----) mesolitoral.
60
40
20
Total
EPA
400
300
200
100
0
mar
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
0
Chthamalus
Month (2004-2005)
Balanus Pollicipes
Chathamalus Balanus Pollicipes
500
100
Spring 04
Winter 04
80
60
40
20
400
Total
EPA
300
200
100
0
mar
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
0
Month (2004-2005)
Chthamalus Balanus Pollicipes Chthamalus Balanus Pollicipes
500
100
Winter 04
80
60
40
20
Spring 04
400
Total
EPA
300
200
100
0
mar
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
0
Month (2004-2005)
Chthamalus Balanus Pollicipes
Chthamalus Balanus Pollicipes
500
100
Spring 04
Winter 04
80
60
40
20
400
Total
EPA
300
200
100
0
mar
apr
may
jun
jul
aug
sep
oct
nov dec
jan
feb
mar
0
Month (2004-2005)
Chthamalus Balanus Pollicipes
Percentage (%) of P. pollicipes adults
that presents, at least, a recruit in the
peduncle (±S.E.) throughout the
sampling period.
Our results pointed toward that recruitment period of C. montagui was affected by the Prestige oil spill.
The recruitment period of the oiled localities (Cabo Home, Couso and Caldebarcos) at the three
mesolitoral levels is during summer and autumn (June-October) and has a duration of 4-5 months. In the
case of the control site (Segaño), we can differentiate between the upper and middle mesolitoral, where
the recruitment is observed during 6 months, from spring to autumn (April-October), and the lower
mesolitoral, in which recruits can be observed on the plates during almost all year (March-January).
Highest recruitment level for C. montagui is reached at all localities during the summer, although in
Segaño high values can be observed too at the lower mesolitoral in April-May and October-November.
Maximum recruitment in Caldebarcos, the heaviest oiled locality, is significantly lower than in the other
sites. Something similar occurs with the cumulative number of recruits over the year which is significantly
lower in Caldebarcos and significantly higher in Segaño (control site) than in the other locations.
The number of recruits collected throughout the year is higher at the lower mesolitoral than at the upper
and middle one, except for Caldebarcos, that presents very low values at the three levels, not existing
significant differences among them.
In the case of B. perforatus the cumulative number of recruits over the year is significantly higher in
Segaño (the control site) than in the other localities. Recruitment is only observed at the lower mesolitoral.
Maximum recruitment is reached, in Segaño, during March-June and September-December, and in
Caldebarcos, during September-December. In Couso and Cabo Home, there aren´t important peaks and
just few recruitments were collected from March to December.
Again, the cumulative number of recruits of Pollicipes pollicipes over the year is significantly higher in
Segaño (the control site) than in the other locations. The recruitment patterns at the four locations are very
similar. Two recruitment periods, one from February to May and another from July to February, can be
clearly observed.
50
Segaño
Caldebarcos
Couso
Cabo Home
40
Chthamalus Balanus Pollicipes
Concentrations of the PAHs measured in the
three studied species
Cumulative number of recruits (with se bars)
20
PAHs concentrations (µg/Kg)
40
80
PAHs concentrations (µg/Kg)
50
(Control site)
60
Spring 04
Winter 04
PAHs concentrations (µg/Kg)
100
80
500
PAHs concentrations (µg/Kg)
150
100
PAHs concentrations
100
Percentage of P. pollicipes with recruits (with se bars)
200
Percentage of P.pollicipes with recruits (with se bars)
120
250
Percentage of P.pollicipes with recruits (with se bars)
140
Mean number (with se bars)
Segaño
Mean number (with se bars)
300
Pollicipes pollicipes
Percentage of P.pollicipes with recruits (with se bars)
Balanus perforatus
Percentage of P.pollicipes with recruits (with se bars)
Chthamalus montagui
30
20
10
0
2000
Segaño
Caldebarcos
Couso
Cabo Home
1500
1000
500
0
Chthamalus
Species
Pollicipes
Annual percentage of P. pollicipes
adults that presents, at least, a recruit
in the peduncle (±S.E.)
Balanus
Cumulative number of recruits of
C. montagui and B. perforatus
(±S.E.) collected per location.
ACKNOWLEDGMENTS
Project funded by “Ministerio de Educación y Ciencia” (VEM2003-20070-C04-02). MPA would
like to aknowledge “Universidade de Vigo” for economical support.
Thanks to the scientific staff of the “Estación de Bioloxía Mariña da Graña” for field assistance
and to Julia Ameneiro for her help.
REFERENCES
-Kennish, M.J. (1997) CRC Press, Boca Raton, Florida. 524 pp.
-Menge, B.A.(2000) Ecol. Monogr., 70: 265-288.
-Roberts, D., Rittschof, D., Holm, E., Schimdt, A.R. (1991) J. Exp. Mar. Biol. Ecol., 150: 203-222.
-Sanders, H.L., et al. (1980) J. Mar. Res., 38:265.