EPIBENTHIC COMMUNITIES IN TWO CONTRASTING AREAS OF THE BALEARIC ISLANDS Montserrat Ramón(1 2) Pere Abelló(2) Xisco Ordinas(1) Alberto Serrano(3) Montserrat Ramón(1,2), Pere Abelló(2), Xisco Ordinas(1), Alberto Serrano(3), Enric Massutí(1) (1) IEO ‐ Centre Oceanogràfic de les Balears ‐ IEO (2) Institut de Ciències del Mar – CSIC (3) Centro Oceanográfico de Santander ‐ IEO Final workshop IDEADOS: “THE WRAPPING UP OF THE IDEADOS PROJECT, INTERNATIONAL WORKSHOP ON ENVIRONMENT, ECOSYSTEMS AND DEMERSAL RESOURCES AND FISHERIES” Palma de Mallorca 14‐ 16 November 2012 Palma de Mallorca, 14‐ 16 November 2012
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EPIBENTHIC COMMUNITIES IN TWO CONTRASTING AREAS OF THE BALEARIC ISLANDS
Montserrat Ramón(1 2) Pere Abelló(2) Xisco Ordinas(1) Alberto Serrano(3)Montserrat Ramón(1,2), Pere Abelló(2), Xisco Ordinas(1), Alberto Serrano(3), Enric Massutí(1)
(1) IEO ‐ Centre Oceanogràfic de les Balears ‐ IEO( ) g f(2) Institut de Ciències del Mar – CSIC(3) Centro Oceanográfico de Santander ‐ IEO
Final workshop IDEADOS:
“THE WRAPPING UP OF THE IDEADOS PROJECT, INTERNATIONAL WORKSHOP ONENVIRONMENT, ECOSYSTEMS AND DEMERSAL RESOURCES AND FISHERIES”Palma de Mallorca 14‐ 16 November 2012Palma de Mallorca, 14‐ 16 November 2012
INTRODUCTIONINTRODUCTION
Many studies have been conducted in the Mediterranean addressing megafaunal demersalassemblages (Abelló et al 1988; Cartes and Sardà 1993; Stefanescu et al 1993; Sardà et alassemblages (Abelló et al., 1988; Cartes and Sardà, 1993; Stefanescu et al., 1993; Sardà et al.,1994; Moranta et al., 1998; Carrassón and Cartes, 2002; D’Onghia et al., 2004). Most of them arebased on fish and decapod crustaceans, which are the most abundant groups in Mediterraneanepibenthic communities.
In the Balearic Islands, studies on megafaunal assemblages (mainly fish, decapod crustaceans,cephalopods and echinoderms) have been performed on the continental shelf and slope, from 40to 750 m depth (Massutí & Reñones 2005 Moranta et al 2008 Ordines & Massutí 2009)to 750 m depth (Massutí & Reñones, 2005, Moranta et al., 2008, Ordines & Massutí, 2009).
In the present study we have taken into account the overall taxocenoses present in samplescollected with a beam trawl of 10 mm diamond mesh cod‐end.
OBJETIVES
To analyze the existence of spatial and seasonal variations of megafaunal communities present inthe bottom in two areas of Mallorca (Sóller and Cabrera), along a depth gradient from the shelfedge to the middle slope.
SAMPLING
On board the trawler “Punta desVent”
EPIBENTHIC BEAM TRAWL:
horizontal and vertical openings: 3 5 mhorizontal and vertical openings: 3.5 mand 0.6 m respectively
10 mm diamond mesh cod‐end10 mm diamond mesh cod end
Each haul lasted 15 minutes at atowing speed of 2.1 knotsg p
The sampling area varied between 679and 1136 m2
A SCANMAR system and CTD fitted tothe upper part of the beam trawlmouthmouth
SAMPLES CHARACTERISTICSSAMPLES CHARACTERISTICS
Beam trawlnumber
Cabrera Cabrera Cabrera Sóller Sóller Sóller Total
Depth estrata Shelfedge
Upperslope
Middleslope
Shelfedge
Upperslope
Middleslope
9‐17 DEC 2009 2 2 2 2 2 2 12
Mean depth (m) 305 708 875 252 649 848
Depth range 262‐347 704‐711 852‐898 228‐276 622‐664 843‐852
Codes of assemblages correspond to area (Cabrera/Sóller: C/S), depth stratum (Shelf edge, Upper slope, Middle slope: S/U/M), and season (December/July: D/J).
Canonical Correspondence Analysis
Sample labels on circlesand squares representstrata (Shelf: S, Upperl U Middl l M)
M MM
slope: U, Middle slope: M);
colours are white for Julyand grey for December;
SAL
DEPGRA
COS ShShShSh
Sh MM
MM
M
circles correspond to Sóllerand squares to Cabrera.
Th i t l l b l
TEM
Sh
Sh
ShShShSh UU U
U M
MMM
U
The environmental labelsrepresent depth (DEP),salinity (SAL), temperature(TEMP), %gravel (GRA),% d (COS) %fi
Sh organic content (POS), and%total organic content(POM).
Conclusions
The present study has shown the existence of differences at community levelbetween two contrasting areas separated 50 nm. These differences wereid i h h lf b k d h l ( ) b i hevident in the shelf break and the upper slope (228‐738 m), but not in the
deeper waters of the middle slope (843‐900 m). The fact that our studydetected locality differences also in the shelf break is probably due to takingi t t th ll t t i th l i f linto account the overall taxocenoses present in the samples, since faunaldiscontinuities are not always sharp and they hardly ever coincide acrossanimal taxocenoses.
Seasonality has been found in the shelf break (228‐347 m) and upper slope(646‐738) assemblages in both areas, but not in the middle slope. This seasonaldifferences in faunistic assemblage dynamics may be attributed to differencesdifferences in faunistic assemblage dynamics may be attributed to differencesin the relative abundance of the species or also to important presence/absencepatterns of key species related to migration/aggregation in relation withreproduction.reproduction.
ACKNOWLEDGEMENTS
We are deeply grateful to all participants in the IDEADOS surveys on board R/V “Sarmiento de Gamboa” and F/S “Punta des Vent”.