IBUTION OF THE OOPELATA OF THE ALCATRAZES AREA

Vol. VII, Fase. 1 e 2, p. 113 - 115.

ON THE UNEVEN DISTR,IBUTION OF THE

OOPELATA

OF THE ALCATRAZES AREA

CWith a map a nd one tab!e)

T. Ií.. S. Bjornberg cf L. Forneris

*

The present paper deals with the Copelata collected during the voyage of the yacht "Igaraty", owned by Dr. Adalberto Ferreira do Valle, who kindly put it at the service of the Instituto Oceanográfico of the Uni-versity of São Paulo, from June 26 to June 29, 1954. The samples were collected by Prof. VV. Bernard and Dr. Ingvar Emílsson. On Table 1 is the list of stations, their position, dates, number and percentage of the species in each sample as well as the characteristic data of the water of the surveyed area. All the plankton samples were collected with a standard net (Sverdrup et al, 1954, p. 379, figo 91-d).

The percentage composition of the more frequent species at each station is given in Fig. 1. At all the stations (excepting station 10)

Haplopleura longicauda was the most abundant species. Oikopleura

fu-sifonnis and Fritillaria pellucida were the next in abundance.

The observation of the hydrographical data (as DI'.

r.

Emílsson per-sonally informed us), showed that the surveyed area was under the in-fluence of three water masses: A - coas tal waters (of low salinity and medium temperature ); B - northern waters (of high salinity and high temperature); C - deep water (of medium salinity and low tem-perature) .

The comparison of our own with the hydrographical data shows that stations six, seven and nine, characterized by a large frequency of

Oikopleura rufescens, were strongly influenced by northern waters and

that stations five and eight, characterized by a large percentage of

Haplopleura longicauda, Oikopleura f~tsifonnis and Fritillaria pellucida

were situated in mixed waters. The small differences in the percentages of species in these last two stations may be due to the fact that the collec-tions were made at different hours of the day. Stacollec-tions one, ten and eleven were under the influence of coastal waters. At station ten, the great

-114 ~

abundance of F . haplostoma may be explained by a swarm of this species, a fact commonly observed in superficial coas tal waters (Tokioka - 1951, p. 18 ,& 1955, p. 253). Stations ten and eleven aIs o show such a small influence of northern waters (see Fig. 1) that O. rufescens there occurred in insignificant quantities.

The inversion in the frequency of H. longicauda and O. fusifonni s

in the samples from station ten may be due to the different hours in which the collecting was made.

It is strange that O. dioica was not found in pure coas tal \Vater. This neritic, euryhaline and eurythermic species seems to avoid certa in types of coas tal waters (Russell & Colman, 1935, p. 228). We may con-clude that the northern waters of this region were characterized in these samples by the presence of O. rttfescens; the coastal waters, by the pl'esence of F . pellucida; and that F. haplostoma was found there in swarms. We did not consider the influence of the thermoclyne to be significant in stations five and nine where it was observed at 40m and at 20m clepth respectively because the quantity of water filtered by the net under the thermoclyne was very small when compared to the quantity of \Vater filtered abo~ ' e it, so that it was here considered to be irrelevant.

It may finally be added that the occurrence of T ectillaria f ertais

(station eight) in our samples widens the southern boundary of the distribution of this species, known up to now from 15· North upward<: in the Atlantic Ocean (Lohmann, 1896, p. 30).

SUMARIO

Neste tra balho são estuda dos os Copelata coletados durante a viagem do " Iga · ra ty" à Ilha de Alcatrazes. A lista das est ações, sua localização, as da tas e outros dados sôbre as águas da á rea pesquisada, assim como o número e a porcentagem de ocorrência de cada espécie em ca da amostra estão na T a bela 1. 'l'ôdas as coletas foram feitas com uma rêde "standard" (Sverdrup et aI - 1954, p. 379, figo 91·d). Comparando os dados hidrográ ficos, fornecidos por informação pessoal do Dl'.

I. Emílsson, com os nossos, podemos concluir que, n estas amostras, as águas vindas do norte (vid e estações 6, 7 e 9) são caracterizadas pela presença de O. ,·njescen .•

em grande abundância; as águas costeiras, pela presença de F. peUnoida (vide es-tações 1 , 10 e 11) e as águ as misturadas (vid e eses-tações 5 e 8, Tabela 1 e Figura 1) são caracterizadas pela ocorrência de H . longioa"da, O. j"siform is e F. pellttoida

em freqüências elevadas. Houve ocorrência ainda de "nu vens" de F. haplostoma

na estação 10, fato com um em águas costeiras e superficiais do J a pão (Tokioka, 1951 e 1955).

A influência da t ermoclin a observada nas estações 5 e 9 não foi considerada significativa pois foi p equ ena a qu antidade de água atravessada pela l'êde a ba ixo dela, em comparação com a grande qua ntida de ocorrida acima da mesma . O

apa-recim en to de Teotilla"ia fertiUs aumenta o limite sul de distribuição desta espécie no Atlântico, pois era conhecida apen as nas correntes qu entes do h emisfério norte dêste oceano (Lohm ann, 1896, p. 30).

ACKNOWLEDGEMENTS

115

-REFERENCES

LOHMANN, H., - 1896. "Die Appendicularien der Plankton Expedition". Ergeb. Plankton Exped., Vol. 2 F. c. - p. 1-148, 20 taf., 3 cart., 1 diagr.

RUSSELL, F. S. & COLMAN, J. S., - 1935. The Zooplankton IV. 'l'he occur-rence & seasonal distribution of the Tunicata, Mollusca & Coelenterata. Great Barrier Reef Exp. 1928-29. Vol. 2 (7), p. 219-231.

SVERDRUP, H., JOHNSON, M. W. & FLEMING, R. H., - 1954. The Oceans. X

+

1087 p. Prentice-Hall, Inc. New York.

TOKIOK.A., T., - 1951. Pelagic Tunicatcs & Chaetognaths col!ected during the cruises to the n ew Yamato Bank in the Sea of Japan. Publ. Seto Mar. Biol. Lab., Vol. lI, n.9 I, p. 1-25.

S.SebastLão

_..

Is .

oAleat-razes Is. (lSUO

1:.:"::':·:;:::1

No ...

thern

'w'~ters

(B)

...

,

-

.. ... ...

.

..

.

.. -.. " .. ' . . ..

-_-. ....

...

.

.. .. .. .... .. ..

.. .. .. .. ... .

-St.5' ·:·· '. 43~B ." ... . .

'-< "

...

.. ..' ":. ....

-45°/,./

F I g u r e I.

PERCENTAGES OF SPEClES PE~ SUTIO!;

CHARACTERISTICS OF WATER "ASSES :

A: 1181.%0 " 33.5

tempo '" 2 r.6

( CO AS TAl IriATE R}

8: sal.%" " 36.8

temp o ,. :N,O

(NO f/ T~[IIN 10' .1. 1( 11)

C: sal. %" " 35.6

tempo " 15,'1

(OH P ... TEII)

S P E C I E S :

~ Oi kOPleura fus l tor",is

_ F r i t i l 1 a r l e . pe1hçc;lcr.

_ r r U l 1 1 a r l & fI.plostOlN

TABLE 1

~ Deplh

Time OIKOPLEURA FRITlLLARIA Tec tilla ria Total af Total af

S ta tion Date Longi tude La titude _{Depth(m) :} Loca l :=> Sample of T emperature _'C Salinity _%~~" h Haplopleura lo ngicauda fusi fo r- co?ho- haplos- ~~rmica borea is Oikopleu~ Fritilla - TOTALS (m) mi s ru fescens cerca gracilis Sps. pellucida loma digi tata sa r gas.~i Sp. fe rtilis ridae riclae

1 26/6/5h 24°06' S ú6 014 , W l1J _~ O 2.1,7 33 , h8

8 6 21,5 33,66 23 , 00 8

-

-

-

-

3

-

-

-

-

-

-

11 O 11

~ 12 21,4 33,77 (72 , 70%) (27.27%)

5 27/6/54 25°26' S lL5025 , w 106 O 2.1,9 35,09 lb, 5Z 4B 12

-

-

-

2 8

-

1

-

-

-

62 9 71

6 21, 8 35 , 02 ( 67 ,60%1 n 6.9O% ) (2.81)1) <11.26% n.M%)

~

ti 12 21 ,6 31,17

f:: 18 l 1,!! 35 , 36

~ 30 20 , 6 35 , 60

45 16,9 35, 54

h8

-

-6 27/6/54 25°09 ' S Uh'55 ' W 12.1 O 22 , 9 35 , 93 20 , 35 15 - 3 1 1 1

-

_-

-~ 6 22 , 8 35 , 92 (65.21%1 (13.Oh( 1 1 1 _- (h.3l!%) ( h.3l!%) (4. 3l!% ) 20 3 23

~ 12 22 ,8 35,96 (h . 3l!% ) (4 . 3l!% )

~ 18 22 ,8 35,96

30 229 36 40

7 27/6/5h 5002 ' S l.W0h2' w 136 O 23 ,3 36 ,hO 23 , 55 1 - 1 - -

-~ 6 23 ,9 36,'.U. h9 6 5 (1.61%) (1.61%) 60 2 62

~ 12 23 , 2 36,L1l (79.03%1 (09 . 67~ ) (B . 06:h )

-

_-

-!i 18 23 , 8 36 , M

30 23 3 36 , Uh

8 28/6/5h ~'50' s h50l2' W 82 O 21 , 8 34 , 99 0l1 , 55 h2 - - - 1 119 43 162

~ 6 21 ,7 3U ,99 107 8 3 l? - - (25 .92% ) (0 . 61)1)

;: 12 21 , 3 35 , 70 (66 . 04.%1 (01.h 9u;,: (1. 85%)

~ 18 21,lJ 35 , 6u

30 21,2 35,uO

9 28/6/5h lh"35 ' s u5027' w 69 O 2l ,7 35 , 01 09 ,15 8 5 2 - - 2 - - _. - 1

-

15 1 16

~ 6 21 , h 35 , 01 (50 . 00%1 01 . 25% ) ( 12.50%) (12.50%) (6. 25% )

~ 12 2l ,3 35,48

I:: 18 21,6 35 , 86

30 17,8 35 , 90

10 ~ 13 , 30 1, 080 931- 2 - - - 186 u, 919

-

8 -

-28/6/5h 24006 ' s u50u3 ' ."

-

i

0 - 3 21, 85 3u , ZO (15.15%) (13.06 %) (0 . 02% ) (2. 61%) (69.02% (0.11%) 2 ,013 5 ,ll3 7,126

285 56 882 2 482 940 l,h26

g 16,30 199 2

- - -

-

-

-(13. 95% ) (19 . 97% ) (0.116\) 0092%) (61.85% (0. 11' )

U 29/6/% lhOOh' S 4 6007 ' W

-

About2::m 21,98 33 , 63 lh,15 2 , 331 398 56 - 193 4.16 147 - - _- - 2 ,988 563 3, 551

at Qn. st Om . (6 5 , 50%) (11 . 20% ) <1 . 5.1%) (5 . h3%) (ll.n%) (4 .14.%)