SYMPOSIUM on Marine Accidental Oil Spills
Suprabenthic communities in Galician beaches (NW Spain)
after the Prestige oil-spill
Barriocanal, Irene; Frutos, Inmaculada; Viéitez, José Manuel & Junoy, Juan
Depto. Zoología y Antropología Física. Universidad de Alcalá. 28871 Alcalá de Henares. Spain
ABSTRACT
Three Galician beaches (Corrubedo, Frouxeira and Altar; NW Spain) were sampled to know
their respective composition and abundance of suprabenthic fauna after the Prestige oil-spill.
These three reflective beaches have different morphodynamic characteristics and sediments
(see details, Junoy et al. 2005).
Sampling program (of Project VEM 2004-08544) began in September 2005 and will finish in
December 2007 (24 months). The present comunication deals with the autumn and winter of the
year 2005 (September to December, 2005).
There was used a hand-pushed suprabenthic sledge which has an opening of 50 cm wide and
20 cm high equipped with a 0.5 mm mesh net. Ten tows (10 m length) were undertaken in the
swash zone parallel to the shoreline once a month at the three beaches during daylight low tide.
Total sampling area was 50 m 2 by beach and month.
Corrubedo beach, with a 2900 m length, showed the highest mean density values ranged
between 616.18 ind./5 m2 in October and 14.63 ind./ 5 m2 in December. The highest species
number in this beach was collected in October (20 species) and the lowest in November (10
species). The isopod Eurydice affinis represented more than 50% of specimens collected (Mean
abundance: 153.6 ind./5 m2); in October 4264 individuals were collected in the ten tows. Other
abundant species were the mysid Gastrosaccus roscoffensis (16.8% of individuals; mean
abundance: 51.5 ind./ 5 m2) and the cumaceans Cumopsis longipes (Mean abundance: 27
ind./5 m2) and C. fagei (Mean abundance: 25.8 ind./5 m2) with 8.8% and 8.4% of dominance
respectively.
Frouxeira beach, with a 3000 m length, showed a mean density values ranged between 46.9
ind./ 5 m2 in October and 16.1 ind./ 5 m2 in November. Number of species varies between 12
(September ) and 7 (October). In this beach, the mysid Gastrosaccus roscoffensis accounted for
more than 50 % of specimens collected (mean abundance: 21.7 ind./ 5 m2); other dominant
species were the isopods Eurydice naylory ( 22.2%, mean abundance: 9.4 ind./ 5 m2), Eurydice
affinis (9.7%, mean abundance 4.1 ind./ 5 m2) and Eurydice pulchra (7.7%; mean abundance:
3.3 ind./ 5 m2 ).
Altar beach, with a 950 m length, showed the lowest abundance ranged from 29.8 ind./ 5 m2
(November) to 5.2 ind./ 5 m2 (December). The isopod Idotea pelagica with a mean abundance
in this beach of 6 ind./5 m 2 accounted for 24.3 % of specimens. Other abundant species were
the amphipods Pontocrates arenarius (15.7%; Mean abundance: 3.9 ind./ 5 m2) and Atylus
swammerdami (8.4%; Mean abundance: 2.1 ind./ 5 m2). Altar beach was the only beach where
it was collected young fish as suprabenthic fauna.
REFERENCES:
Junoy J., C. Castellanos, J. M. Viéitez, M. R. de la Huz and M. Lastra, 2005. The macroinfauna
of the Galician sandy beaches (NW Spain) affected by the Prestige oil-spill. Marine Pollution
Bulletin 50, 526-536.
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