Notes on the benthic macrofauna of Agadir Bay (Atlantic Morocco)

2010·8.6 MB·English

by  Abdellatif Moukrim

,
© SociedadEspañoladeMalacología Iberas, 28 (1): 97-114, 2010
Notes on the benthic macrofauna ofAgadir Bay (Atlantic
Morocco)
Datos sobre la macrofauna bentónica de la Bahía de Agadir
(Marruecos Atlántico)
AbdellatifMOUKRIM*,José Enrique GARCÍARASO** and Serge GOFAS**
Recibidoel16-IV-2010.Aceptadoel30-IV-2010
ABSTRACT
The macrofauna collected ¡n 25 dredge hauls from subtidal soft bottoms (6-25 m) ¡n
Agadir Bay, Southern Morocco, is listed. Seventy species are identified, chiefly Mollusca
but also some decapods, echinoderms, and polychaetes. The results show four main
assemblages with a similarity above 50%. The community of soft bottoms is quite homoge-
neous within the bay and is comparable to the community of fine sands with Chameleo
striatula - Mactra corallina as described by Glémarec (1969, 1973) and with the shallow
well calibrated fine sandy bottoms (SFBC) or 'terrigenous' fine sandy bottoms (Pérés and
Picard 1964; Ledoyer, 1968). Towards the deeper part there is an increase of Ophiura
texturato together with an increase in mud content. A more significantly different commu-
nity is associated to bottoms with rocks in the northern part of the bay. Almost half of the
species identified belong to the temperóte European (Atlanto-Mediterranean) faunal
province whereas one quarter belong to the tropical West African province. Despite the
modest sampling effort, there are five species of molluscs Nassarius goreensis, N. argen-
(
teus, Cuno gambiensis, Tellina rubicincta, Pandora oblonga) new to the Moroccan fauna,
indicating the need for a more thorough survey in the area.
RESUMEN
Se presenta una lista de las especies de la macrofauna recolectada en 25 dragados en
fondos blandos sublitorales (6-25 m) de la Bahía de Agadir, Sur de Marruecos. Se identifi-
caron 70 especies, principalmente moluscos, pero también decápodos, equinodermos y
poliquetos. Los resultados de este estudio muestran cuatro grupos de especies con una
similitud superior al 50%. La comunidad de fondos blandos es bastante homogénea den-
tro de la bahía y se corresponde con la comunidad de arenas finas con Chamelea striat-
ula -Mactra corallina descrita por Glémarec (1969, 1973) y con la de arenas finas bien
calibradas poco profundas (SFBC) o arenas finas terrígenas (Pérés and Picard 1964;
Ledoyer, 1968). Hacia la parte más profunda se aprecia una mayor abundancia de
Ophiura texturata, así como un incremento de la proporción de fango. La comunidad más
diferente se encuentra en un fondo con rocas en la parte norte de la bahía. Aproximada-
mente la mitad de las especies pertenecen a la provincia faunística europea templada
(Atlanto-Mediterránea) y cerca de una cuarta parte a la provincia tropical del Oeste
Africano. A pesar de lo limitado del muestreo, se citan cinco especies de moluscos nuevas
para la fauna de Marruecos (Nassarius goreensis N. argenteus, Cuna gambiensis, Tellina
rubicincta, Pandora oblonga), lo que pone de manifiesto la necesidad de una prospec-
ción más intensa en este área.
LaboratoireEauxetEnvironnement, FacultédesSciences, B.P. 28S,Agadir(Morocco).
* DepartamentodeBiologíaAnimal, FacultaddeCiencias, E-29071 Málaga(Spain).
97
Iberus, 28 (1), 2010
INTRODUCTION The purpose of this paper is to present
some results regarding the benthic
The benthic fauna of the Atlantic macrofauna (chiefly Mollusca and
coast of Morocco is known quite ade- Decapoda) of the soft bottoms which
quately for bathyal environments constitute most of the bay, and to draw
sampled by deep-sea expeditions (see some preliminary conclusions regarding
reviewinSalas, 1996andGarcíaRaso, benthic communities and their biogeo-
1996) or for the intertidal communities graphicsetting.
accessible from the shore. The subtidal
environments in between have received
little attention and their species compo- MATERIALAND METHODS
sition remains largely unknown. Previ-
ous data are mainly based on a sam- A set of samples (Figure 1) was col-
pling programme conducted in the lected in May 1999, using a rectangular
years 1924-1925 with the trawler dredge with an opening of 50 cm,
mm
"Vanneau", following the foundation of geared with a net of 10 mesh. The
the Instituí Scientifique Chérifien, dredge was towed by a boat at a speed
Morocco's Natural History Museum in of approximately one knot, for 15
1923 (Liouville, 1930). However, only a minutes, parallel to shore at each posi-
small part of the material obtained was tion on a transect. Three transects were
eventuallystudied. sampled perpendicular to shore, in the
The geographical situation of the vicinity of Oued Souss, which was the
Bay ofAgadir falls mid-way within the target area for an environmental impact
so-called "Mauretanian región" of study, and within each transect four
Ekman (1953). Thus, it is important to samples were taken at 10, 15, 20 and 25
determine how much of its fauna m depth. Two other transects and some
belongs to the European températe samples were taken with the same gear
province, as does most of Atlantic at the northern end of the beach (D),
Morocco, and how much belongs to the inside the harbour (E), and in front of
tropical West African province. The bay the suburb ofAnza (F),justnorthwestto
marks the end to the north of a very the harbour. In each of the transects D
long stretch of coastline with a broad and F, samples were taken, at 6, 10, 15,
shallow continental shelfciad with sedi- 20 and 25 m. Samples were sorted
ments, and bordered by long, straight immediately uponreturn to the lab, and
sandy beaches exposed to heavy surf. the animáis preserved in 70° ethanol for
Northwards, Cape Ghir sets a sharp furtherdetermination.
physiographic limit to a predominantly The literature used for species iden-
rocky shore with a narrow platform; a tification was not specific to the area.
comparable sandy shore resumes only The fauna of both Western Europe and
much further to the north along the West Africa has been considered.
CoastalplainsofBouregregand Sebouin PasteurHumbert(1962a,b), Poppeand
Northern Morocco. Thus, this physical Goto (1991, 1993) and the unpublished
boundarymay contributeto sharpenthe manuscript on West African Bivalvia by
northwards boundary of any West RudovonCosel (MNHN)werethebasic
African elements likely to occur in the references for the Mollusca; Monod
area. The area of Agadir is also coinci- (1956), Forest and Gantes (1960) and
dent with a major area of upwelling ZariqueyÁlvarez (1968), amongothers
(Mittelstaed, 1983), which makes it for the decapods, Tortonese (1965) for
potentiallyspecies-rich. the echinoderms. The polychaetes were
The growing concern for conserva- identified by Patrick Gillet (of Instituí
tion and control of water quality has d'EcologieAppliquée,Angers, France).
triggered new interestfor thebenthos in Sediment samples were taken by
nearshore environments cióse to the SCUBA diving along the three transects
large urban agglomeration of Agadir. ofOued Souss (A: 30° 18' N, B: 30°20' N
98
MoukrimETAL.: Noteson the benthicmacrofaunaofAgadirBay(AtlanticMorocco)
30°25'
30°20‘
Figure 1. MapoftheBayofAgadir,withlocationofthesamplingstations.
Figura 1. MapadelabahíadeAgadir, conlaubicacióndelasestacionesdemuestreo.
and C: 30° 227 N), in order to determine bution of the different species, the
granulometry using a column of stan- SIMPERroutinewasapplied.
dard sieves.
PRIMER software (Clarke and
Warwick 1994, Clarke and Gorley, RESULTS
2001)wasused inthe studyofthe struc-
ture of the communities and their The list of all collected species
spatial variations using qualitative data amounts to 70 (Table I). There is an
without transformation and standard- increase in species richness with dis-
izados Possible significant differences tance from shore. Molluscs and
between transects and depths were decapods are the best represented
assessed using the ANOSIM routine. groups, whereas polychaetes probably
Samples were grouped according to were undersampled due to the kind of
theirfaunal compositionusingthe Bray- dredge used, which skims the superfi-
Curtis similarityÍndex. Inthecluster the cialpartofthesediment.
mode group average was selected. The The sediments are essentially fine
samples were then plotted with a non- sands in transects A and C (range of
metric multidimensional scaling (MDS median 0.17-0.32 mm). The pelite
routine) and, toknowthelevelofcontri- content is very low nearshore and
99
Iberus, 28 (1), 2010
Table I. List ofspecies collected in the dredgings. The * denotes species sharedwith “sables fins á
Venusgallina -Mactra corallina” and “sables fins envasés aPharus legumen - Ophiura texturata or
denoted as characteristic offine sand communities by Glemarec (1969). W: West african species.
The abundance ofspecies is coded (1) 1-2 specimens, (2) 3-5 specimens, (3) 6-10 specimens, (4)
over 10specimens.
Tránselo118'N Transect30?20'N
depth (m) 10 15 20 25 10 15 20 25
MOLLUSCAGASTROPODA
Belasp.
Bivetiellocancellata(Linné, 1758) W 2 1
Bullíamiran(Bruguiére, 1792) W 3 4 3 2 4 4 2
Calyptraeacbinensís(Linné, 1758)
Clanculuskraussí(Philippi, 1846) W
Cabestanadolaría(Linné, 1767) W
CymbíumcucumísRoding, 1798 W 1
Epitoníumturtonís(Turton, 1819)
Euspirafusca(deBlainville, 1845) 1
Euspirapulchella(Risso, 1826) 1
Marginellaglabella(Linné, 1758) W
Mesalíavaria(Kiener, 1844) W 2 4 3 1
Mitrellasp. 1
Nassaríusargenteus(Marrat, 1877) W 111
Nassaríuselatus(Gould, 1845) W 2 4 1
Nassaríusgoreensís(vonMaltzan, 1884) W
Nassaríus¡ncrassatus(Stróm, 1768)
Nassaríusretículatus(Linné, 1758) 3 2 1
Nassaríusvaucherí(Pallary, 1906) W 1 1 1
OcenebrabrevírobustaHouart,2000
Pbilineaperta(Linné, 1758) 1
Stramonítahaemastoma(Linné, 1758) 11
Solatíapiscatoria(Gmelin, 1791) W 1 2 2 1
Tectonatícasagraíana(d'Orbigny, 1844) W 1
W
Volvarinasp.
MOLLUSCABIVALVIA
Anomíaephippium(Linné, 1758) 114 1112
Abraalba(Wood,1802) 4r
Chameleastriatula(daCosta, 1778) 4c 1
Corbulagibba(Olivi, 1792) 2 2
CunagambíensísNicklés, 1955 w
Donaxi/¡Mus(daCosta, 1778) 4c 2
Dosiníalupinus(Linné, 1758) 4c 1 1 1 1
*
Ensisensis(Linné, 1758)
Garifervensis(Gmelin, 1791)
Macomacumana(Costa, 1829) 1 1 1
Mactracorallina(Linné, 1758) 4c 1 2 2
100
MoukrimETAL.: Noteson thebenthicmacrofaunaofAgadirBay (AtlanticMorocco)
Tabla I. Lista de especies recolectadas en los dragados. El *indica especies quese han citadopara las
comunidades denominadas “sablesfins a Venus gallina - Mactra corallina”y “sablesfins envasés a
Pharus legumen - Ophiura texturata” o indicadascomo característicasdecomunidadesdearenafina
porGlemarec(1969). W:Especies Oeste-Africanas. Laabundanciadelasespeciesestaanotadacomo (1)
1-2ejemplares, (2)3-5ejemplares, (3)6-10ejemplares, (4)másde10ejemplares.
Transect309Tí!N NorttiofBeach Harbour OffAnza
10 15 20 25 6 10 15 20 25 6 6 25 6 10 15 20 25
2
1 1
4 3 4 2 4 4 2 4 1 4 1 1 2 4
i i
i i
2 1
1
1
1
1
i i
i 1
2 1 4 4 1 1 4 1 4 2 3 2
i
i
1 1
2 1 3 3 1 4 4
2
4 2 1 1
3 4 1 2 4 4 4 2 3 4
1 4 4 1 1
2
1
1
1 1 1
1 1 1
2
1 1 2 1 1 4 3 1 2 4
2 2 1 4 1 2 2 4 2 2
2 1 2 1 4
i
i
1 1 1 4 1 1
1 1 2 4 1 1
1 1 1 1 1 1 1
1
1 1 1 4
2 1 1 1 2 3 1 1
101

N N
Iberm,28 (1),2010 MoukrimETAL.-.NotesonthebenthicmacrofaunaofAgadirBay(AtlanticMorocco)
TVaebnluesgI.alLliisntao-fMsapcectireasccoorlallelcitnead"ianndth“esadbrleedsgifnignss.enTvhaesé*sdkePnhoatersusspleecgiuemsesnha-rOepdhwiiutrha"tseaxbtluersatfainsoár cToambluaniId.aLdiesstaddeenoemspienciaedsarsec“oslaebclteasdfaisnsenellVosendruasgagdaolsl.inEal-*Miancdtircaaecsopreaclielsinqau"eyse"shaablnescfiitnasdoepnvaarsaéslahs
denotedascharacteristicoffinesandcommunitiesbyGlemarec(1969).W:Westafrtcanspecies. Pharuslegumen-Ophiuratexturata", oindicadascomocaracterísticasdecomunidadesdearenafina
Theabundanceofspeciesiscoded(1) 1-2specimens,(2)3-5specimens,(3)6-10specimens,(4) porGlemarec(1969). W:EspeciesOeste-Africanas.Laabundanciadelasespeciesestaanotadacomo(1)
1-2ejemplares,(2)3-5ejemplares,(3)6-10ejemplares,(4)másde10ejemplares.
Transect30®18' Transect30»20' Transecf30e22'N NorthofBeach Harbour OffAnza
depth(m) 10 15 20 25 10 15 20 25 10 15 20 25 6 10 15 20 25 6 6 25 6 10 15 20 25
MOLLUSCAGASTR0P0DA
Setosp. 2
Bmliellocancellata(linné,1758) W 2 1 1
Bullíamiran(Bruguiére,1792) W 3 4 3 2 4 4 2 4 3 4 2 4 2 4 1 2 4
Calypbaeochinensis(linné,1758) 1
Corotostara(Philippl,1846) W 2 1
CohesionadatariaOtoñé,1767) W
CymbiumcacaraisRóding,1798 w 1
EpitomaraMonis(Turton,1819)
Easpirolasca(deBloinville,1845) 1
Euspirnpulchello(Km,1826) 1
Marginellaglabella(linné,1758) w
Atentorano(Kiener,1844) w 2 4 3 1 1 4 1 4 2 3 2
Afeitosp. 1
Hassaiiasargénteas(Morrat,1877) w 14
Atossoitoselalus(Gould,1845) w 2 4 1 1 1 1 2 3 3 4
bassariusgoreensis(vonMoltzon,1884) w 211
bassatiasinaassatus(Strom,1768) 4 2
bassariusreticolatus(linné,1758) 3 2 1 3 4 4 4 4 2 3 4
bossanosvaacheri(Pollory,1906) w 1 1 1 4
OcenebwbrevirobastaHonor),2000 2
Philineapeita(linné,1758) 1
Stromoaitabaemastoma(linné,1758) 12 11
Solabapiscatoria(Gmelin,1791) w 2 1
Jectonohcasogtaiano(d'Orbigny,1844) w 1
Vaharinasp. w 2
MOLIUSCABIVALVIA
Anemiaephippium(linné,1758).
Atoonton(Wood,1802) 2 4
C/iome/eosWoft/to(doCosto,1771 2 2
Corbulagibba(Oírn,1792)
Cunojomifens/íNkldés,1955
Donmviltolus(doCosto,1778)
Dosinialupinos(linné,1758)
teeos»(linné,1758)
6(70fe/vens/5(Gmelin,1791)
Atomoratono(Costo,1829)
Ataracorallina(linné,1758)
100 101
Iberus, 28 (1), 2010
TableI. Continuation.
TablaI. Continuación
W
Modiolusstultorum(Jousseaume, 1893) 1 1
Iransectoír Ib' N Iransect3Uy2U N
depth (m) 10 15 20 25 10 15 20 25
Nuculanabicuspidata(Gould, 1845) W 3 1
Pandoraoblonga(SowerbyJ830) W
Pandora¡naeguivalvis(Linné, 1758) 1 2 1
Parvicardiumexiguum(Gmelin, 1791) 12
Pharuslegumen(Linné, 1758) 1 1 2 2 1
Pbaxaspellucidus(Pennant, 1777) •k 1
ScaccbiazornivanAartsen&Fehr-deWal, 1985
Sinupbaruscombieri(Fischer-Piette&Nicklés, 1946) W
Spisulasubtruncata (daCosta, 1778) 1 1
k
Jellinatenuis(daCosta, 1778) 1
TellinarubicinctaGould, 1845 W 1
k
TellinafabulaGmelin, 1791 2 1 1 1
k
Thraciapapyracea(Poli, 1791) 1
Thyasiraflexuosa(Montagu, 1803) 2
MOLLUSCACEPHALOPODA
Sepiettaoweniana(d'Orbigny, 1839) 2
SepiolarondeletiLeach, 1817 2
CRUSTACEADECAPODA
Diogenespugilator(Roux, 1829) k 3 3 li4 li
k
Liocarcinusd.bolsatus(Fabricius, 1798) 2 2 3
Liocarcinusdepurator(Linné, 1758)
Macropodiarostrata(Linné, 1761) 2
k
Philocherastrispinosus(Hailstone, 1835) 3 1
PolybiushenslowüLeach, 1820 1 1
Scyllarusarctus(Linné, 1758) 1
PYCNOGONIDA
Nymphonsp. 1
ECHINODERMATA
Ecbinocardiumsp. 1
*
OpbiuratexturataLamarck, 1816 4 4 1 4 4
ANNELIDAPOLYCHAETA
CirratulusfilíformisKeferstein, 1862 12
DiopatraneapolitanaDelleChiaje, 1841 1 1 4 4 3 3
tugiapterophora(Ehlers, 1864)
MagellonapapillicornisMüller, 1858
Nepthyssp 1
102
MoukrimETAL.: Noteson thebenthicmacrofaunaofAgadirBay(AtlanticMorocco)
TableI. Continuation.
TablaI. Continuación
Transect309Z2'N Nontiotbeacn Harbour UttAnza
10 15 20 25 6 10 15 20 25 6 6 25 6 10 15 20 25
1 4 1 2 2 3 4
4
1 4 4 3 1 3 3
3
1 1 1 1 1 1 2 1 1 1 1 1 1
lili
1
2 1 4 1
2 3 1 2 3
2
1 1 1 1 1 1 1
2 2 4
4 3 2 3
2 2 2 1 2 2 3 1 1 4 3 1 2 2
2
111 1 2
2 3 3 11
1
1 1
4 4 2 4
1
3 4 1 3 3 3
1
1
103