[Ilex Coindetii and Todaropsis Eblanae (Cephalopoda, Ommastrephidae): Their Preserit Status in Gaiician Fisheries By

, .. 1 '" j \ ... , '. .

International Council for the C.M. 1992/K: 5 Exploration of the Sea Shellfish Commitee . ~ 1

[Ilex coindetii and Todaropsis eblanae (Cephalopoda, Ommastrephidae): their preserit status in GaiiCian Fisheries by

Angel F.Gonzalez, Mario Rasero and Angel Guerra Instituto de Investigaciones Mannas (CSIC), Eduardo Cabello 6. 36208 Vigo, Spain

Summary

• Post-recruit //lex coindetii and Todaropsis eb/anae were collectCd from the fishery on the Galician shelf between November 1991 and April 1992. Sampies were anaiysed separately considering two area~ with different hydrognlphycal characteristics. ~iaturity was assessed using a maturity scale. Growth was determined using length-frequency and modal-progression analysis. I.coinderii males were more precoucious thim females in both areas; the size at first maturity of this species was the same for males in both areas considered, and higher in the north than in the south area for females. T.eb/anae males were more Precoucious than females in both areas;the length at frrst maturity of this species was the same in both areas for males, and higher in ~e nonh than in the south for females. April in both areas was the begining of a spawriing period for I. coinderii . Tbe spawning season ofT. eblariae in the nonh area stans on February, extending at least until April .Sex moos for both species were calculatCd. In I. coiTufeiii four micrOCohons for females and tJrree for males were found in both areas. Growth rate for each micmcohorts was estimated. Two different growth rhythms , one for Spring broods and other for squi'ds born on ea:rly Summer, were observCd~ Femates 'grow fast(~r änd reach larges size than Jrlales. Life Span oftlus S}iecies waS estil11atCd ofone yeu. In T. eblanae only one micmcoholt for each sex and area was fOllOd, except fcr males in thc north area where two micrOCohöns were defuied. GrOwth rates were estirriatCd. Tbe life span of this species was found to bC cf one year. The relationships between D~ and BW of 1. coindetii. and T. eblanae were estimated too. Tbe landing statistics for the Galichin fishery from 1980 to 1991 are presented. .. 2

•

Introduction

This paper presents the preliminary results of some reeent work on the biology of lI/ex coinderii (Verany,1837) and Todaropsis eb/anae (Ball, 1841) in Galician waters (NW Spain), together with the annuallanding statistics of the Galician fishery from 1980 to 1991. Data are presented on reproduction and growth of both ommastrephid squid species around Galician coast. The present status ofominastrephid squid fishing in Galicia is described. This paper constitutes the first contribution to the knowledge of the life eycle and fishery of lI/ex coindetii in the Atlantie waters of Spain, and the first study ofTodaropsis eb/anae in the Atlantie ocean.

\laterials and methods •

Sarnples ofl.coinderii and T.eb/anae were obtained from eommerciallandings in two pons of the north ofGalicia (Burela and Celeiro) and one pon of the south of Galicia (Ribeira) (Fig. 1). A total of 3000 l.coinderii and 2425 T.eb/anae in 6 sarnples were examined from ;'!ovember 1991 to April 1992. Sampies were eolleeted from both otter and pair trawlers where squids are taken as by-catch of the hake and blue witting fishery. Squid sarnples were separated in two groups according with the area where they were eaught, the north group comprised all squids colleeted from Ribadeo to Finisterre and the south group was formed by the squids eaught from Finisterre to Miiio river (Fig.l). The distinction of both areas was done.. taking into account the existenee of clear different hydrographie conditions (Fraga et al.,1982), which eould have produced two different stocks. Thc squid colleeted in these sampies were sexed and the total body weight (BW) obtained. Thc dorsal mantle length (DML) was measured to the nearest millimiter. Monthly length e frequeney distributions were analysed using Battaeharya method (1967) employing the software paebge ELEFAN (Gayanilo et al.,1989). This modal-progression analysis provides ~ different population subunits, whieh ean be eonsidered as microcohons (Caddy.199l). Growth rates in length for each of these microcohons were ealeulated. Tbe maturity stage was assessed by a maturity seale of 5 stages for males and 6 stages for females. aeeording to the universal maturity seale (Lipinski.1979). but eonsidering the stages 1 and 2 for males as stage 1. ICES SC r I I

0')<

CI) w U

Figure 1. Chan of Galicia (NW Spain) showing the main commercial ports of the nonh (Ribadeo-Finisterre) and south one (Finisterre-Mifio River). 3

Results

Maruration , . Table 1 shows the percentage ofI.coindetii males and females in each maturiyty stage and DML in the Galician north area. Table 2 shows the same information for the south area.

Table 1. Percentage (%) of I. coindetii males and females in each maturity stage and DML classes in nonh area.

Males Females ~ laturity stage 1 2 3 4 5 1 2 3 4 5 6 DML(mm) 60-79 100 • 80-99 100 100 100-119 92.8 6.0 0.6 0.6 100 120-139 48.5 27.8 19.7 4.0 93.3 6.7 1~0-159 3.8 22.3 29.9 44.0 69.1 27.3 1.8 1.8 160-179 0.7 2.8 9.2 87.3 27.0 47.67.9 6.4 11.1 180-199 2.7 2.7 94.6 3.7 53.7 13.4 6.1 23.1 200-219 100 35.6 28.8 13.6 22.0 220-239 5.6 94.4 9.1 38.6 13.7 38.6 240-259 100 11.8 11.8 17.6 52.9 5.9 260-279 100 22.2 22.2 44.4 11.2 280-299 22.2 11.1 55.6 11.1 300-319 16.7 16.7 49.9 16.7 320-339 20.0 60.0 20.0 340-359 60.0 20.0 20.0 360-379 50.0 50.0

I.coindetii males are more precoucious than females in both areas. The smallest mature male measured 119 mm DML in the nonh area and 93 mm in the south one, while the smallest mature fern ales were of 148 and 160 mm DML respectively. The size of the mature males ranged from 119-263 mm DML in the nonh , and from 93-230 mm DML in the south, while the size ofthe mature females ranged from 148-345 mm DML in the nonh area, and from 160 325 mm DML in the south one. Spent males were not found, and very few spent females were caught in the sampies. 4

Tbe size at first maturity ( DML at which 50% of the specimens were mature in the population) was the same (160-179 mm) for males in both areas considered, and higher in the ,.I' north (220-239 mm) than in the south (200-219 mm) for females.

Table 2. Percentage (%) ofI. coindetii males and females in each maturity stage and DML classes in south area.

Males Females Maturity stage 1 2 3 4 5 1 2 3 4 5 6 DML(mm) 60-79 100 100 80-99 98 0.7 1.3 100 100-119 76.0 14.8 3.7 5.5 96.6 3.1 120-139 35.9 29.6 19.5 15.0 92.5 5.7 1.2 0.6 • 140-159 6.3 13.0 33.2 47.5 71.4 24.3 0.7 3.6 160-179 3.3 13.0 83.7 14.8 69.4 9.3 5.6 0.9 180-199 100 5.3 66.7 17.5 5.3 3.5 1.7 200-219 25.0 75.0 14.3 28.6 22.8 34.3 220-239 100 15.2 9.1 30.3 45.4 240-259 21.4 28.6 50.0 260-279 50.0 50.0 280-299 25.0 75.0 300-319 100 320-339 100

, Table 3 shows the percentage ofT.eb/anae males and females in each maturity stage and DML in north area. Table 4 shows the same information for south area. T.eb/anae males are more precoucious than fernales in both areas. Tbe smallest mature male measured 104 mm DML in the north and 98 mrn DML in the south , while the smallest fern ales were af 140 mrn and 141 mrn DML respectively. The size ofthe mature males ranged from 104-169 mm DML in the north area, and from 98-149 in the south, while the size of the mature females ranged from 140-219 mm DML in the north , and from 141-219 mm DML in the south. Spent males (stage 5) were found in both areas,while very few spent females were caught in the sarnples. The size at fIrst maturity was the same (130-149 mm DML) in both areas for males, and higher (180-199 mm) in the nanh than in the south (160-179 mm) far females. 5

Table 3. Percentage(%) of T.eblanae males and females in each maturity stage and DML classes in nonh area.

Males Females Maturity stage 1 2 3 4 5 1 234 5 6 DML(mm) DML

50-69 100 40-59 100 70-89 95.2 4.8 60-79 100 90-109 50.0 46.0 3.6 0.4 80-99 97.6 1.7 0.7 110-129 3.5 61.0 22.7 12.0 0.8 100-119 78.7 20.7 0.6 130-149 4.8 25.3 65.0 4.9 120-139 41.5 48.8 9.7 150-169 15.8 73.7 11.5 140-159 4.2 45.8 45.8 4.2 • 160-179 6.6 13.4 40.0 20.0 20.0 180-199 12.5 18.8 68.7 200-219 10.0 10.0 80.0

Table 4. Percentage (%) of T.eblanae males and females in each maturity stage and DML classes in south area.

Males Females Maturity stage 1 2 3 4 5 1 2 3 4 5 6 DML(mm) DML

50-69 98.0 2.0 40-59 100 70-89 91.5 8.5 60-79 100 90-109 33.1 55.3 8.4 2.7 0.5 80-99 94.4 5.6 110-129 3.2 34.1 37.8 23.1 1.8 100-11958.9 40.0 1.1 130-149 12.8 70.2 17.0 120-139 6.1 73.3 19.0 1.6 140-159 20.7 55.2 10.3 6.9 6.9 160-179 7.7 30.7 61.6 180-199 7.7 38.5 53.8 200-219 16.7 83.3 6

Table 5 shows the monthly percentage ofl.coiwlcrii males and females in each maturity stage in nonh area. The same infonnation for south area is given in Table 6 .

Table 5. Monthly percentage (%) of l.coindetii males and females in each maturity stage in nonh area.

Males Females Maturity stage 1 2 3 4 5 1 2 3 4 5 6 Month Nov. 66.2 14.4 7.2 12.2 58.1 17.1 3.1 6.2 15.5 Dec. 60.9 17.8 6.8 14.5 76.3 7.6 3.8 2.3 8.4 1.6 lan. 50.6 12.1 11.4 25.9 64.2 17.9 6.5 3.3 8.1 Feb. 57.8 14.1 3.1 2.5.0 79.0 14.0 3.5 1.4 2.1 :"lar. 3.8 19.1 43.5 33.6 44.4 39.3 6.6 1.6 4.4 3.7 • Apr. 1.4 0.7 2.1 95.8 4.7 23.1 25.0 13.9 33.3

Table 6. Momhly percentage (%) of I.coindetii males and females in each maturity stage in south area.

~lales Females ~laturity stage ~ 1 2 3 4 5 1 2 3 4 5 6 ~lonth ~ov. 84.6 1.7 1.1 12.6 59.3 7.4 3.7 7.4 18.5 3.7 Dec. 26.6 19.1 21.0 33.3 46.0 41.0 4.0 8.0 1.0 lan. 62.1 11.3 8.1 18.5 73.0 18.2 5.8 2.2 0.8 Feh. 38.6 17.6 19.3 24.5 75.2 19.8 2.6 1.6 0.8 • Mar. 20.9 25.4 20.9 32.8 57.7 31.5 6.3 3.6 0.9 Apr. 8.5 10.4 27.4 53.7 21.5 23.7 11.1 13.3 30.4

During the sampling period. mature males ofl.coindetii were more abundant than mature females in both areas. The relatively high abundance of mature females in April suggests the beginning of a spawning period in both areas. Table 7 shows the monthly percentage ofT.eblanae males and females in each maturity stage in nonh area . The same infonnation for south area is given in Table 8 . 7

Table 7. Monthly percentage (%) ofT.eblanae males and females in each maturity stage in

north area. ~.

Males Females Maturity stage 1 2 3 4 5 1 2 3 4 5 6 Month Nov. 95.7 3.4 0.9 97.9 2.1 Dec. 64.5 34.8 0.7 84.5 12.0 3.5 Jan. 35.7 43.7 18.8 1.8 82.0 14.5 3.5 Feb. 43.7 32.0 11.6 12.7 65.0 19.6 7.7 3.4 4.3 Mar. 31.6 40.7 11.5 15.7 0.5 55.9 25.8 5.3 1.0 12.0 • Apr. 2.5 7.7 17.9 65.4 6.5 15.4 28.8 17.3 7.7 30.8 Table 8. Monthly percentage (%) ofT.eblanae males and females in each maturity stage in south area.

Males Females Maturity stage 1 2 3 4 5 1 2 3 4 5 6 Month Nov. .. 15.8 32.3 29.3 21.8 0.8 30.2 49.6 15.1 1.6 3.5 Dec. 38.9 38.2 11.7 10.3 0.9 60.7 26.1 8.4 0.9 3.0 0.9 Jan. 27.7 39.7 21.7 8.4 2.5 46.9 44.4 7.4 1.3 Feb. 27.4 45.0 14.8 12.8 76.4 21.3 2.3 Mar. 1.5 15.1 33.3 36.3 13.8 11.3 38.7 9.7 17.7 22.6 Apr. 72.0 20.4 2.2 5.4 93.7 3.7 0.8 0.8 1.0

These results suggest that the spawning season of T. eblanae in the north area starts in February, extending at least until April. On the other side, the presence of a few number of mature males and females in November could indicate the existence ofanother spawning period on Autumn or that the spawning period ofthe species extends from February to November. In the south area, the results shown in table 8 indicated the existence ofa maturation peak on March. 8

Sex ratio Tables 9 and 10 show the monthly variation of the number of males and females for hoth ... species considering hoth areas separately .

Table 9. I.coindetii sex ratio and Chi-square results; n.s=no significant different; *= signifficant different (p<0.05). M= males; F= females.

Area / Month Nov Dec Jan Feb Mar Apr Total Ratio

North M 84 127 154 120 127 133 745 1.04 F 123 121 114 132 124 101 715 1.00 * n.s * n.s n.s * n.s

South M 34 161 124 122 136 109 686 1.06 F 28 102 139 123 113 139 644 1.00 n.s * n.s n.s n.s * n

Table 10. T. eblanae sex ratio and Chi-square result ; n.s=no signiffkant different; *=signifficant different (p<0.05). M=males; F=females.

Area / Month .. Nov Dec Jan Feb Mar Apr Total Ratio

~orth M 111 157 104 120 102 90 684 1.18 F 90 143 83 117 92 53 578 1.00 n.s n.s n.s n.s n.s ** • South M 133 136 83 116 66 83 617 1.13

F 119 109 81 94 62 81 546 1.00 n.s n.s n.s n.s n.s n.s *

The monthly sex ratios ofI. coindetii vary significantly (p< 0.05) from the theoreticall: 1 ratio in November, January and April in the nonh area, and in December and April in the south area. While the pooled sex ratio of the species in both areas was not signicantly different from 1:1 in both areas. NUMBER OF 'I], NOVEMBER 91 OECEMBER 91 IANIJAI/V 92 'JARCH 91 AI'RIL 9\ SPECIME NS .0 OMALES 40 n 1122 nll09 C51fEMALES

'0 .UNSUED SOUTH '0 AREA 10

'0 '0

eo tlORTH

AREA • 40

120 180 240 300 360 120 180 240 JOO 360 120 180 240 300 380 120 '802«) 300:)6Q 120 180 240 300 JeO 12'0 '80 240 JOQ .leO OMICulln. Figure 2. Monthly length frequency distributions oflllex coindetii

NOVEMBER 91 DECEMBER 91 JANUARY 92 FEBRUARV 92 MARCH 92 APRIL 92

""UMBER OF DMALES SPECIMENS CJfEMAIES eo .UNSEXED .0 01133 nl\36 '"83 't: E6 SOUTH 40 AREA ,0

20 nF, 109 nFI81 11162 nFI81 '0 nUI4 nUI3 nUI14 40

NORTH '0 AREA '0

50 100 150 200 '0 100 150 200 ~ ,o0 "0 200 so '00 150 200 '0 100 1'0 200 OMl(mmt Figure 3. Monthly Iength frequency distributions ofTodaropsis eblanae . ~------l .. .. Mo. Mo• e SOUTH ARU AI" Spa"""'''U M-.on , fE_ES Mo, " L"!o~~! J... " ", , .lul " "- , "- Au. , "" "- "- So. , "." "- " "- 0" '. , ...... N.. ,,-' "- "- 0.... Jon ,... '>~~~ ~.. "" ..."" ...-.... .•..•. -..• M.. ~ ;50 '.~..... _'--, ... A.. -".ra ~... K I l'" H 10 11 ...... 171 ...... 10 "" ttllu-l- .. .. NOlIIH ARU 1.4., SOUIH AREA - ~ '.-.0-' MALES MALES ...... !·.!t~! ...... " "- " "- ...., ...... " " So. " " ...... " "- ...... Oc' ", "- ...... 0" N.. , . 0« 1>0< '~ III Jon• '~.'''~ Ion hb ...... _.,u. ,..,

Mo< 04 '"'~ E M.. A•• t" ------r JO At· >0 ...... • 11 >0 11 '" '.. .. Oll OMltfTftl I ... OMllmm'

Figure 4. I//ex coilldcrii ll10nthly modal values ami growth pallern of microcohons. " MONIHII

,_ M... IH .....' NORIH ARU Ap. Ap. "- SOUIH AREA Mo, rEMALES Ifo, HMALIS J. " !~d!~O~.! !b~~n_.! J.n ~~! •.!t!!'! !.bl~"-~ J.I " Jul A '" A " " '" ", S., 5., '. " "- Ocl "- Oel "- No. , .. No. 0'" o.c ~.o. 0., '" " '0' 92 Je.. .. ljl Ju "'-. "J "\ r.b .or "- ,.121 0'" leb 0"' .IU, A .103 ~9S " '.0 Mo. M•• .110",, . Ap. .U! .., ... 0'" Ap' 0" ~ U '0 .. lOG '10 >oe> '0 .. '00 " ... H' ." '" " . OMllmm)

MONIHS MONIHS 01 ah. ,. M•• NORIH AREA Apr Ap. 50UIH AREA MAUS Mo, !~!~Of!'.! !b~~~ Mo, " MALES J.n " Jun "- !~~.-'!'p~~ !bJ8_"!!. J.I " ", Jul Au. " Au " Sop " " " "'- " 0.. " 0" " "- No. No. ' .. ."J

.. "'2 00< 0 101 12 J.n '01 91 Jen 0"' .UJ rob .. .., hb 0" IJ , M. Mo. '00 .. '.. C Ap, \ • 1U "p• 0" ooe )'3'

U '0 n '00 'U '.. .. 10 .. 100 '10 DMllmml '" OMllmmt

Figure 5. Todaropsis eblanae monlhly modal values and growlh pattern of microcohorts. 9

The monthly T.eb/anae sex rauos wem not significIDltly different fr()m the expected 1:1 ratio during the perlod sampled except in April in the north area. \Vhile the pooled sex ratio of the species was significantly different from the theoreticall:l ratio in bOth areas. ' .

Growth ~lonthly length frequency distributions of I.coindetii are illustrated in Figure 2. Figure 3 shows the monthly le:ngth frCquency distributions ofT.eb/anae . FerriaIes reach larger size than males in both species. Figures 4 arid 5 shown the monthly modal values obtained and growth pattern of each microcohon found ofI.coinderii and T.eb/anae respectively. In I. coilidetii four microcohons for females and thTee for males were found in both areas. Estimated growth rare for microcohon A in females ofthe nonh area was 28 mm DMLI month. The esümated growth rate for microhon B was 22 mm DML /month, arid growth rates for microcohons C and D were 17 and 19 mm DML / month respectively. The growth rates of microcohorts E, Fand G for males in this area were 27, 25 and 17 mm DML / month. Assuming these growth rates in juveniles, the spawning season of these microcohons ranged from March to July, which is in agreement with the observed from maturation data. It seems that two different growth patterns exist. one for spring broods and other for squids born on early summer. Growth rate for females microcohort H in south area was 30 mm DML / month. For microcohon I it was 26 mm DML / month, and 20 rrim DML / month for microcohoit J. Tbe values for males were 24 mm DMUmonth (microcohon L), 19 mrn DMi../month (M) and 18 mm DML / month (N). Assuming these grOwth rates in juveniles, the spawning season will be from March to July. It seems aIso that two different growth rhythms exis·t. as found in the nonh area. In T. eb/anae orily one microcoholt for each sex and area was found, except for the males in the nonh area where two microcohons can be: defirie:d. Estimated groWth rate far the ferriäles

. .'.'. " '" .' '." . '. '" . .. ',. ' mlcrocohort 10 the nonh area was 15.7 mm DML / month. Tbe growth rates for males B and C microcohorts in this area were 14.7 mm DML j month and 6.25 mm DML /month respectively. Assuming a linear growth for this species arid these growth rates in juveniles, mi':focohoris A arid B could indicate that spawn occurs in April, which is in agreement with maturatiori

Lengrh and Weighr ~,. The relationships between DML and BW of I. coinderii are shown in Table I1.The slope was always higher for males than for females, and similar values were found in both areas.

Table 11. I.coinderii length-weight regressions expressed by the equation WB=aDMLb. BW in grams; DML in millimeters; N=number ofspecimes; r 2 = coefficient ofdetermination;

Males Females Area a b N a b r 2 N

~onh 0.0000017930 3.567 0.947 774 0.000014442 3.099 0.969 721 South 0.0000016358 3.579 0.916 638 0.000012246 3.124 0.963 644

The relationships between DML and B\V ofT.eblanae are shown in Table 12.The slope was always higher for males than for females, and moderately higher in the nonh than in the south area.

Table 12. T.eblanae length-weight regressions expressed by the equation WB=aDMLb. BW in grams; DrvlL in millimeters; N=number ofspecimes; r 2 = coefficient of determination;

Males Females .-\rea a b r 2 N a b r 2 N

~onh 0.000106601 2.917 0.971 684 0.000316192 2.671 0.978 582 South 0.000276544 2.714 0.971 627 0.000555929 2.552 0.972 541 ~

Thejishery Tbe squids I. coindetii and T. eblanae are collected as by-cateh in Galician trawl fisheries. The target species are mostly hake, blue witting and Norway lobster. Vessels working in these fisheries are otter and pair trawlers. In 1991 the number ofotter trawlers and pair trawlers in the north area (Ribadeo-Finisterre) was 38 and 6 respectively. The main ports in this area are Burela. Celeiro and Coruna. In that year the otter trawlers figured about 45 and pair trawlers were 7 in the south area (Finisterre-Mifio river). The main ports in this area are Ribeira. Marin and Vigo. These ships are steel and wood trawlers, which have 25-30 meters ofoveralilength. ! ;

, , , .GAUCIA (NW SPAIN) .'. GAUCIA (NW SPAIN) CATCHES GROUND NORTH(YEAÄ-86) CATCHES GRCuND NORTH(YEAR-87) <:5-t1------, OtTUiUlStTepftülsquUls

••...... •...... '< e , •

2 3 • 5 6 7 8 9 10 II 12 2 3 • 5, 6 7 .." 8 9 10 11 12 tJONTHS ~S

GALlCIA (NW SPAIN) , .GALlCIA lNW SPAIN) CATCHES GROUND NORTH(YEAR-88) CATCHES GROUND NORTH(YEAR-89)

2 3 • 5 6 7 8 9 10 11 12 2 3 • 5 6 7 8 9 10 11 12 MONTHS MJNTHS

, . , GALlCIAlNW SPAIN) GALICIA lNW SPAIN) CATCHES GROUND NORTH(YEAR-90) CATCHES GROUND NORTH(YEAR-91)

16-rr------~~---~-::-~~---.., <:5------ep-/i=-U-:'s-q-u"":"'Uls-::-----, ...... 9.~!::f.~!'!.:~i!:. _... 0mmas tTi 14

2 3 • 5, 6 7 8 9 10 11 12 2 3 • 5 6 7 8 9 10 11 12 tJONTHS MJNTHS

Figure 6. Monthly landings of ommastrephid squids for the period 1986-1991 in the north area ofGalicia. GALICIA (NW SPAIN) ,GALICIA lNW SPAIN) CATCHES GROUND SOUTH (YEAR-86) CATCHES GROUND SOL'TI i{YEAR-87) 25..r"------, OmmastrepfiU[squUfs •••..•.Q.~!!"~p.~w.~~l!~ .•• ~ ..-...... •.....•...•....••..•.••.•...... ••

2 3 <4 5. 6 7 8 ; 10 11 12 2 3 <4 5, 6 7 8 9 10 11 12 ~NTH5 t.Om-IS

GALICIA (NW SPAIN) GALICIA (NW SPAIN) CATCHES GROUND SOUTH(YEAR-88) CATCHES GROUND SOUTH(YEAR-89)

JC~------,

(/) g=1 <.) 80 Cf t- W EiO ~

':l ::'0

2 3 4 5 6 7 8 9 10 11 12 2 3 4 5 6 7 8 9 10 11 12 MONTHS MONlHS

GALICIA (NW SPAIN) GALICIA (NW SPAIN) CATCHES GROUND SOUTH(YEAR-90) CATCHES GROUND SOUTH(YEAR-91)

OmmastrepfiitlsquUfs OmmastrepfiitlsquUfs

(/) 80 (/)80 § t- § <.) 60 <.) EiO t-c:: W ffi :':40 ~40

2 3 4 5 6 7 8 9 10 11 12 2 3 4 5 6 7 8 9 10 11 :2 ~NTHS MONlHS

Figure 7. ~tonthly landings of ommastrephid squids for the period 1986-1991 in the south area of Galicia. GALICrA fNW SPAIN) GALICIA fNW SPAIN) - .• -TOTAL CATCHES (YEAR-86) TOTAL CATCHES (YEAR-87)

...... OmmastTfiid__ .. _-----~-_ ...s~ids.. _-_ ...- ..._- _-_ .._------.._- .._-- .

2 3 4 5 6 7 8 9 10 11 12 2 3 4 5 6 7 8 9 10 11 12 MJNTHS M:)Nl"HS

l , , , , GALICIA (NW SPAIN) GALICIA fNW SPAIN) TOTAL CATCHES (YEAR-88) TOTAL CATCHES (YEAR-89)

~ 1 _ g1 o Ci: 80 I- W ~60

10 20

2 3 4 5. 6 7 8 9 10 11 12 2 3 4 5 6 ~ e 9 10 11 12 ~'ONTHS ~'ONTHS

GALICIA (NW SPAIN) GALICIA ~NW SPAIN) TOTAL CATCHES (YEAR-90) TOTAL CAT HES (YEAR-91)

1 _ .;.;.~.C?~!:~p.~!'!.~P.:i:f!.

Cf) 80 Cf)

§ § 80 060 0 Ci: Ci: I- I- 60 W W ~4O ~ 40

20 20

2 3 4 5' 6, 7 8 9 10 11 12 2 3 4 5 6 ' 7 .. 8 9 10 11 12 MJNTHS MONlHS

Figure 8. ~1enthly totallandings cf emmastrepnid squids fer the peried 1986-1991. GALICIA (NW SPAIN) GALICIA lNWSPAIN) TOTAl CATCHES TOTAL VALUEOFTI-lECATCHES

2C',tY\,~------,'r:.rn'Y\.A"------., Ornmastrepfiitlsquitfs Ornmastrepfiitlsquitfs .. ..•.•.....••..•••••••...•• . . 20000~··············----······ -- . ~ e1 ~1 Cl ~ 1 Ö ~

80 81 82 83 84 85 86 87 8S 89 90 91 80 81 82 83 84 85 86 87 88 89 90 91 YEAR YEAR

GALICIA (NW SPAIN) GALICIA (NW SPAIN) TOTAL CATCHES IN GROUND NORTH TOTAL VALUE IN GROUND NORTH

1,rYY'L~------"" •...... Omma.strepfiitlsquitfs

80 81 82 83 84 85 86 87 8S 89 90 91 80 81 82 83 84 85 66 87 88 89 90 91 YEAR YEAR

GALICIA (NW SPAIN) GALICIA (NW SPAIN) TOTAL CATCHES IN GROUND SOUTH TOTAL VALUE IN GROUND sotfrH

,r:.tYV~------, Omma.strepfiitlsquitfs Omma.strepfiitlsquitfs 20000~····-··················· ....-•.....••.•

~ ~ (5 1 ~1 t- a.. U=: Cl tu 1 ~1 ::l :::: Q i=

80 81 82 83 84 85 86 87 8S 89 90 91 80 81 82 83 84 85 86 87 88 89 90 91 YEAR YEAR

Figure 9. Total annuallandings and values of the catches of ommastrephid squids from 1980 to 1991 in Galicia. 1 1

and average of gross registerCd tonnage of 155 metric tons, arid an average propulsion power of 379 H.P. Crew is 7-9. Fishing is carried out iri local fishing grourids from 100 to 350 meters depth. These ships have not frozen facilities, they come back to the port generally ciaily, .'! lariding fresh fish in the fishing markets where it is sold every evenirig in public auction sale. No distiriction is riiäde betWeen both species, which Me used for human consumptiori. Monthly landing of ommaStrephid squids for the period 1986-91 in nonh and south areas are shown in Figures 6 irnd 7. Figure 8 shows the monthly totallandings for tbe same perioid; and Figui-e 9 illustrates the annuallandings arid values of the catches from 1980 to 1991. Total laridings of these speCies ranged from 2,352 metric tons in 1987 to 490 metric ions in 1985. The price varied from 94.2 pw per Kg in 1987 to 156.2 ptas per Kg in 1990. Landings were higher (83.6 %) in the south than in the rionh area dunng the period 1987-1991, while in the previous yeai's (1980-86) a reverse situation was found. Lowest landings were in summer, while highest laridings occUred generally in spring arid autumn (Fig.8). Although the squid fishery has not been managCd, it seems to be in a good ·condition. Nevenheless, in order to avoid overfishing, some fishing regulations would be advisables.

Discussion

From the matured inviduals observed in I. coinderii it was concludedthat males mature at smaller sizes thirn fern ales. The size range at which mature males arid females were found in Galician waters practically coinddes with the observed by Mangold-WirZ (1963) and Sanchez (1981) in the western Mediterranean and Coelho and Borges (1982) offthe Ponuguese coast. Iri the preserii paper the begining of the spawning period was centered in April, but furiher studies are riecessary in order to test whether the spawning period of this species exiends uniil Gctober-November as found by Mangold-Wirz (1963). Burukovski et al. (1979) • Sanchez (1981) and Coelho and Borges (1982). The estimated grow rates ofI.coindetii were higher than those found by S:1nchez (1981). • .. • ~ .' .. • .' ". • , Ä'., who estimated a life span of3.5-4 years. Assuming a linear growth ofjuveniles with growth rates similar to those estimatCd in this work, the life span ofthe species in Galiciari \vaters Will be abotii one year. This agrees with the obserVed by Mangold-Wirz (1963) arid BÜrukovski et al. (1979) for this species, arid in other ommaStrCphid species sttidiCd frOm lerigih frequency distribütions and from scitoIith gröwth incrementS: I/lex i/lecebrosus ( Squires. 1967; Radtk:e, 1983); l/ieX argentinils (Hatanilka~ 1986; Brunetti, 1988; Arkhipkin. 1990; Arkhipkin arid Scherbich. 1991; Rodhöuse and Hatfield,1990); and Todarodes angolensis rVillanueva, 1992). Females ofl.coiiuletii had a higher growih rate ihan males in the Galician waters; feniales growth faster arid reach larger size than males. This is in agreement with the observed by 12

Mangold-Wirz (1963) and Burukovski et al. (1979) in I.coindetii , and by Rodhouse and Hatfield (1990) in I. argentinus . Coneeming to T. eblanae, a wide range of sizes with mature males and females was observed. This range is wider than that observed by Mangold-Wirz (1963) in the Cataloriian sea. However, there was not any size with 100 % of mature specimens. This eould indicate individual varüitions at the maturation size more than a eontinuous growth of the animals after complete maturation, as found by Harman et al., (1989) in Sthenoteuthis oualaniensis • This situation fouod in T. eblanae eould be due to the existenee of different mierocohons in the population. The preeoucity of males in T.eblanae is in agreement with the observed by Mangold-Wirz (1963), Coelho (1982) and Joy (1989). Tbe remarkable preponderanee of mattire males over mature fernales in the sampies observed eoineides with the observations by Coelho (1982) off the ponuguese eoasts. Aeeording to this author, we think that this eould indicate a bathYrnetric or geographie sexual segregation. In the present paper the beginning of the spawning period for T.eblanae was centered in February-March, but funher studies are necessary in order to test whether the spawning period 01' this species extends until October- November as found by Mangold-Wirz (1963) in the :-vtediterraean sea and Burukovski et al.(1979) in the central-east Atlantic. :-vtaturation data ofT.eblanae found in March in the south area, specially for females, have a difficult interpretation. A sudden inerease in the pereentage of mature animals was observed. but this was not followed in April, when almost a total absence of mature animals was found. Tbe sampie of,March was eaught in Marin and the rest of the sampies in Ribeira. Marin trawlers ure more powerful than those from Ribeira. Often they fish deeper than the Ribeira trawlers, :md ean reach the nonhem fishing grounds. Taking into account these two facts, the maturauon peak found in March could be explained by two eauses: a) beeause the March sampie was caught at deeper water than the other sampies, which indicate a bathymetric segregation, with mature animals in deepest waters; or b) because the March sampie was caught in the north urea. This possible explanation gives as'consequence an almost total absence ofmature animals in the 50mh area duririg the sampling period, which could be explained by a nonhward migration of the mature animals to spawn. Males ofT.eblanae were always more abundants than females in Galician sampIes. Tbe sex ratio found was very similar to that estimated by Mangold-Wirz (1963), but it was in disagreement with the observed by Joy (1989) in sampIes from Scottish trawlers. The continous presence of small specimens of T.eblanae «100 mm DML) during the sarnpled period shows the existence of a eonstant recruionent from November to April. The estimated growth rates for T.eblanae were higher than those found by Mangold-Wirz (1963), who estimated growth rates between 4.6 and 6 mm DML I month, and a life span of

.... ~ , .. .' .. " two years. Assuming a linear growth ofjuveniles with growth rates similar to those estimated in this work, the life span of the species in Galician waters will be about one year. This agrees. with the observed by Burukovski et al. (1979) in T. eblanae, and in other ommastrephid species studied from length frequency distributions and from statolith growth increments: lI/ex illeeebrosus (Squires, 1967; Radtke, 1983); lI/ex argentinus (Hatanaka. 1986; Brunetti, 1988; Arkhipkin, 1990), Todarodes angolensis (Villanueva, 1992). As far as we know the only length-weight regression calculated for T.eblanae is own to Cooper (1979), who employed 88 south-african specimens and made not sex distiction. The results obtained by this amhor (a=0.000235, b=2.67) were similar to those presented in this paper.

Acknowledgements \Ve thank MI T Fem::indez , F.Casas , B.Santos, F. Rocha. J. Alt~n and Dr. A J. Figueras for their technical assistance and helpful criticism.

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