, 'd" This Report not to be cited without prior reference to the authors. International Council for the C. M. 1976/J:12 Exploration of the Sea Pe1agic Fish (Southern) Committee Ref. Demersal Fish (Southern) Committee :,,: •... ~~ t·; I ! t \. ) REPORT ON A CRUISE BY THE R. V. "G. O. SARS" TO THE AC;ORES ANP THE'COAST OF PORTUGAL NOVEMBER/DECEMBER 1975 edited by - M. Lima Dias, Instituto das Pescas e Recursos Aqu;Hicos, Lisbon K. Olsen and O. J. {Z)stvedt, Institute of Marine Research, Bergen l INTRODUCTION ,," As part of an agreement between Portugal and Norway on co-operation in fisheries development, the Norwegian research vessel "G. O. Sarsll from the Institute of Marine Research, Bergen operated in the bank areas southwest of Portu al, around the A~ores and along the coast of Portugal in November-December 1975. The programme was planned and carried out in co-operation with scientists from research institutes in Lisbon under Secretaria de Estado das Pescas, who also had consulted with fishing administration and active fishing skippers from the A<;ores. 'The purpose of the cruise was to make an assessment of distribution and abundance of fish in the areas of particular importance for Portuguese fishing vessels, giving highest priority to a survey near the A~ores. and to obtain a general picture of the einvironment in ~ ~) -:.;.... -.. relation to fish distribution.:,··~ Responsible for preparing parts of the report have been Hydrography: R. Leineb!1S Plankton: Kr. Fr. Wiborg , : ·.Äcoustic: M. Lima Dias and K. Olsen Figures and Tables: S. Myklevoll and P. Skjoldal NARRATIVE . , "G. O. Sars" sailed from Bergen 1 November and arrived 8' No'vember in Lisbon' where the research staff from institutes under the Secretaria de Estado das Pescas in Portugal joined. After departure from Lisbon 9 November. a survey was made on Gettysburg Bank, Ampere Bank and Josephine Bank. From Josephine Bank a direct course was set to the Aqores where fishing banks and shelf areas were surveyed between 11 November and 1 December. During the cruise "G. O. Sars" called at the following ports in theA~ores: Ponta Delgada 17-18 November, Horta 25 November and Angra do Heroismo 30 November where masterfishermen from the A'iores joincd the expedition. - 2 - - I~GLO:.iSalx:slld:tietuJlnerl>::.tOn<LisJDPnl~fU4üD~cGI1;lb~ri:lf!EilJ<;>'ffi ~/rHqPl~~~~r an r~<!Q.'y;s.tiC1:§.U:l{y~yd~'ß 1rn<il;d~n~long~ tl:n~kf?QEtJ1gu\.~pe.(.cq'?-E t a~ft~.JilO"YJ1if:J1 "G. O. Sars" sailed direct1y to Bergen where she .,~,,)"~ye,<;l·d,:~ P.Y51HBger. The scientific and technicial staU participating in the cruise or part 'Qfaih!Wlerro:> b91>"!OJ~"! 8iiW yiia!1sb tlblhr;q 08.LWLJ ~Iodvr tuB gahliG •-raiOITtY:lf19'u;q2J1n'I:J g0.ibl:o:J:)'I .G gniau rliqob 'm e 1s Norway, Institute of Marine Research (Bergen): ?J::!~f!,!_~~ ~l_ !'3!'_ !1_0!:!~::~q<:<:~ B. Brynildsen, K. Hansen, L. Kalvenes, H. P. Knudsen, O. Knutsen, R. Leinebp (5 Nov. -6 Dec.), S. Myklevoll, :b'J~~U 3"!:)':7 a"!s:>!J gnz...voIIol orIT K.OIsen (16 Nov. -14 Dec.), A. Romslo, K. F. Wiborg (5-16 Nov.), O. J. ~$ivedt (5. Nov.:.(L Dec.). .. l..l. Od 0&18 naom (rH I. .\.1 j "r~jG[f!Glh in:) d[ ,ion Y.GbUL • I • .(M: 1.) ff1S[rlBrl:):)[f1 gnL20b rIHw Portugal, Secretaria de Estado 'das Pescas (Lisbon) : 9~ia rlaom ,i:;:l!1 :-:ilduoh ,·:r:..d~)cnGib IT1:) Oö \j~n ognoa .s Maria Emilia Cunha, M. Lima Dias, M. Helia piniz, .(Gd EI) L\ OOe Fernando Lima, L. Gomes Sintra, M. Sobral, Maria da GraZ~oXj1~g~R~~~10GG~18p~om:'b°~H?a~\~fcld~,-r?R7,T,i)JB "1~UO ,(Oi- 2(0) .t{ tdS ~Si2 A Gores (Master fishermen) : (srTI II• ."!qq.G).gnrn:3qo I<'c. ,WB'!.lt ' ~H~',Dl')qoas>rrl. , ,b b'r)! n:::>.G,caI .}. A.Costa, J.Oil, M.A.l}d1leTlo";:,TI) .\ '- J:,n~~ 0'IDUpc1 m!T! r :')s.I2 rlaSffi 9"IGW (01) 220) "!91q!TI.B3 5:::>.1311.1)8 'r9:110 bILG (0() a) i9D ognou srlT INST~rr~11jJJ' ~rrlH.9~~j~)m b~qqifJP9 • triJI;E\ vloB :>I2T :JcOfLf.;q,cl l!Hw -(01) Oe bru, !TI. Oc-OOS 1;10':::1 11~)j}O hwrn .eIunrl LG::>i:hDV fÜ bG8U 2r;w Hvdrography: " . "')h4' -[+~ ~A:f(tri::>a~b orIt oj gnib1:o:J::>,G bGlu.l'rl 2:"'W j~)[r ognoS edT,.!TI. 0 !TI. 02 10 Gj;:;"! .G jr; 9'Iiw rrI 0012 ,dJiw b~)':::~)V10I : DrrlfTI.G'IgO'1q- AJ3:VTI:) The hYdrQg.raphic,Girtvestiga.Ji8fil'i "",e,.r,~ -,ba;13.~d, C>~ v~1:?!?~..rFaJ}'l9.ns.n\V;.Uh"! 9q Nahsen xm/;ei':s.ihgoböttLe1s. and.G b,Mhyther;.JXl,ogr,aph•. ül'he .~,a~~.nilYqoff1t~~ (' watelrlCs an51Hel-[noU~tte·d.[withJ,thedNan&eR bottl~?~1 wi~;~!.l1:?§vd~;EJ};;pigR<l- bwi!h an j inducl;iM~ sa-linpJ11ej:gil:"i'.uA"PGbT,l! {r,o?ll'poP Et.GJ:~pn::: c..rWljl·~1i f.~ ~h~:AfPJce s, Srrth'eO ~a;xirnumvdf1iPthfl(otlGt'h-<e:lNfl.O~en) qq}.tJ~ 3 .i:~aRt~n'flflßJ'<9:PO. cnh~']iT~e 10 bathythermograph was used to a depth of 250 m. .8:JGhua r;:;:la 10 l - 3 - Hydrographie stations were also taken in eonneetion with all fishing stations. In all 34 hydrographie stations and 37 bathythermograph stations were taken. During the whole eruise particle density was reeorded eontinuously at 5 m depth using a reeording transpareneymeter. The following gears were used: Z 1. Juday net, 36 em diameter (0. 1 m ) mesh size 180 p. with closing meehanism (J 36). Z. Bongo net, 60 em diameter, double net, mesh size 500 }.l (B 60). ·3. Otter surfaee sampier, 40 em square opening, mesh size Z63 J.l (OSS 40). Z 4. Isaaes Kidd mesopelagie trawl, 3' opening (appr. 1. 1 m ) mesh size 3 mm square (IKMT 3'). The Bongo net (B 60) and Otter surfaee sampler (OSS 40). were equipped with Japanese TSK flow meters. The Juday net (J 36) was used in vertieal hauls, most oHen from ZOO-50 m and 50 (70)­ o m. The Bongo net was hauled aeeording to the deseription in the CINECA-programme: lowered with 300 m wire at a rate of 50 m per mine and retrieved with a wire angle of 45 0 at a rate of ZO m per mine while the ship moved at a speed of 1.5 to Z knots. 3 The water volume filtered varied between 350-800 m • The Otter surfaee sampier was towed at the surfaee for 10 minutes at a speed 2 of 5 knots, covering a distance of about 1500 rn equivalent to 600 m of sea surfaee. - 4 - The Isaacs Kidd trawl (IKMT 3 ') was towed at 4 knots lor 10-20 minutes in varying depths according to recordings on the echo sounder. The volumes of the plankton sampies from the J36 and B 60 hauls were measured on board with a modified Usachev-Robertson appara.tus. The samples were afterwards inspected cursorily under a Wild 5 s~ereoscopic microscope. Medusae such as Pelagia perla and other large species were removed before volume measurements. Fish eggs, larvae, young Iish and Myctophid fish were sorted and determined if possible, and all material preserved with 5 % of formaldehyde. Tar balls were separated from the ass 40 sampies and deep-frozen if present in any quantity, otherwise preserved together with the plankton samples. The principal method applied throughout the cruise was the use of the hydroacoustic instrumentation onboard the ship, echo sounders and sonar, in combination with trial fishing for identification of • echo traces. In addition exploratory bottom fishing was undertaken at several bank areas. Cruise tracks and positions of fishing statiöns are given on Figs 1, 2, 3, 4 and 5 and in Table 1. For identification of echo traces pelagic trawls were normally u;sed. ""hen conditions for trawling were unfavourable, the traces were aitempted identified by relating them to species known to occur in the area by the experience of local fishermen. l - 5 - a) Hvclroacoustic_J survey method_ The hydroacoustic equipment onboard R. V. "G. O. Sars'l consists of: Survey sonar (SU - 18 kHz) 11 (SK - 120 kHz) Echo sounder (EK - 38 kHz) 11 (EK - 50 kHz) 11 (EK - 120 kHz) tl (EK - 12 kHz) Three· two-channel echo integrators (EQ II) Netsonde (50 kHz) During the survey the EK-38 kHz sounder was connected to the echo integrators and also to computersystem for logging of data. Integrated fish echo intensities can later be used for relative estimates of fish abundance in the area. The method is based on the following main principles (Midttun and Nakken, 1971): Considering a distribution of a fish species within an area, the total amount of fish is found by an area integration, given by the expression T = JA fA . dA (1) where • PA is the average fish density A total area T total amount of fish in the area lt can be demonstrated that the output of an echo integrator is pro­ portional to fish density, when the echo sounder used has a certain depth compensation of the received echoes. When one spccies alone is considered, we can write = CM (2) --- ------------------ - 6 - where M is the integrator deflection and C is a factor determined by the acoustic properties of the fish under investigation. Combining the equations (1) and (2) gives: T =SA?A.