Rapp. P.-v. Réun. Cons. int. Explor. Mer, 180: 432-446. 1982. Distribution and abundance of demersal resources of the CINECA region

Jeronimo Bravo de-Laguna Instituto Espanol de Oceanografia, Laboratorio de Canarias Av. José Antonio 3, S/C Tenerife, Espana

The demersal resources of highest commercial value in the CINECA region are the hakes, sea breams, sciaenids, cephalopods, and crustaceans. They are distributed on the continental shelf and slope, down to 500 m depth, between the Strait of Gibral­ tar and . This paper gives a summary of the current knowledge on the distribution and abundance, in the different zones, of 26 fish species, 3 cephalopods, and 9 crustaceans.

Les ressources démersales les plus intéressantes du point de vue commercial dans la région CINECA sont les merlus, les sparidés, les scienidés, céphalopodes et crusta­ cés. Leur distribution s’étend sur la plateforme continentale et le talus jusqu’à une profondeur de 500 m entre le Détroit de Gibraltar et le Cap Vert. Le présent travail comprend un résumé des connaissances actuelles sur la distribution et l’abondance, dans les differentes zones, de 26 espèces de poissons, 3 de céphalopodes et 9 de crustacés.

Introduction The continental shelf of West Africa, between the demersal species of the CINECA region is presented. Strait of Gibraltar and Cape Verde, is one of the main These are the hakes (3 species), the sea breams (21 fishing zones of the world. The special hydrological species), the sciaenids (2 species), the cephalopods (3 conditions caused by the Canary Current and species) and the crustaceans (9 species). provide good feeding conditions for a large number of pelagic and demersal species. Their economic import­ ance has attracted the interest of fishing fleets from coastal countries of the region and from several Euro­ Hakes pean and Asiatic countries. The fishing activity has not been followed up suffi­ In the CINECA area the following species exist: Mer- ciently by research on the distribution and biology of luccius merluccius, Merluccius senegalensis, and Mer- the most important commercial species and assess­ luccius cadenati. The biology and distribution of these ments of the state of exploitation of these species. species have been studied extensively (Maurin, 1954; While information about the physical, chemical, and Collignon, 1969, 1971; and Domanevsky and Stiop- biological characteristics of the environment has kina, 1973). There are, however, no good data on increased greatly since the CINECA programme, there catch, fishing effort, or fishing areas. Evaluations on is still a significant lack of good data on fishing effort, stock abundance have been done by using data from fishing areas, and catch with a correct break-down by quantitative trawling surveys only (Collignon, 1969; species. Domanevsky and Stiopkina, 1973; Domain, 1974). For these reasons, the CECAF Working Party on Along the coasts of Mauritania, between 75 and 250 Resources Evaluation has not been able to arrive at metres depth, the hakes are estimated to constitute clear conclusions about the state of the resources. 35 % of the total fish biomass. Actually many of the most important commercial Figure 282 shows the vertical and geographical dis­ species seem overfished. An example is the sea bream tributions of the three species. Merluccius merluccius fishery which has been replaced by the cephalopod are distributed from the Strait of Gibraltar to Senegal, fishery. This phenomenon will be discussed later on. but are uncommon south of and disap­ In the present paper, the available information on pear completely south of Cape Blanc. The juveniles are the distribution and abundance of the most important mainly found in shallow waters on the continental

432 A ..36* STRAIT OF GIBRALTAR

. 3 5 *

34*~ • RABAT

33* o -oos 32*o o . SAFI

0 31 * 2 00 2

1 AGADIR 30* CO SIDI 29° ■ . 28 # CABO JUBY

0 - 009 2 7*

.2 6* CABO BOJADOR o o m . 25*

CABO LEVEN VILLA CISNEROS

50 50 - 80C 23* 150 150 - 750

22* CABO BARBAS

J 1 CABO BLANCO

20*

_ CAP TIMIRIS 19“ o 0 CO 18“ 1 NOUAKCHOTT 300 S 17*

150 150 - 16* ST. LOUIS

15 CAP VERDE ■ A 14*

“N

A Merluccius merluccius 0-750 m % Merluccius senegalensis 35 -8 0 Om 1 Merluccius cadenati 150- 600m

Figure 282. Vertical and geographical distribution of the three Merluccius species.

shelf, while the adults occur closer to the continental mainly found at depths of 150-400 m between Villa slope. During the spawning season, the adults move Cisneros and (Domanevsky and Stiopkina, farther inshore, and afterwards out to deeper waters. 1973). North of Cape Juby, the adults occur mainly North of Cape Juby, juveniles less than 30 cm total between 100 and 500 m depth, and fish larger than 40 length are most abundant between 0 and 150 m depth, cm are usually found deeper than 300 m. Between Villa and the main abundance is generally found deeper than Cisneros and Cape Blanc the hake is found between 50 m. South of Cape Bojador young hakes are rarely 300 and 750 m. found on the shelf and they do not occur in the by-catch Poinsard and Villegas (1975), using data on the fish­ of the cephalopod fishery. Juveniles (8-22 cm t.l.) are ing activity of the Moroccan fleet, have made an assess-

28 Rapports et Procès-Verbaux 433 36 * STRAIT OF GIBRALTAR

3 5*

34 *

33 *

SAFI 3 2 * ESSAOUIRA 31*

AGADIR 30 *

SIDI IFNI 29 *

28 * CABO JUBY

27 *

26 * CABO BOJADOR

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CABO LEVEN 2 4* VILLA CISNEROS

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18* NOUAKCHOTT

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A Dentex macrophthalmus 25-500 m ■ Puntazzo puntazzo 10 - 6 5 n a Dentex maroccanus 30 - 500 m ▼ Boops boops 0 - 200 m ODiplodus cervinus 80 -100m • Diplodus sargus 0 - 50 m □ Diplodus vulgaris 0 ~ 5 0 m

Figure 283. Vertical and geographical distribution of sparid species.

ment of the hake. Along the coast of , the assessment using data from 230 trawl stations at 20-500 fishing effort is mainly concentrated on the younger m depth, between 35°N and 20°N. They estimated the part of the stock, age groups 0 to V, found in shallow total biomass of Merluccius merluccius to be about waters between 50 til 150 m depth. The calculated 50000 t, of which 80 % were juveniles. MS Y for this part of the stock is 3300 tonnes/year. This Merluccius senegalensis is an African species distri­ figure is probably an underestimate due to lack of data buted from the southern coast of Morocco to Guinea, from other fleets fishing on the older part of the stock with the highest abundance between 20°N and 13°N in the same area. (Fig. 282). Maurin (1954) has described the biology of Domanevsky and Stiopkina (1973) have made an this species along the coast of Morocco. The vertical

434 distribution of M. senegalensis changes according to the in the yields of sea breams has been observed, (Garcia seasons of the year. In winter the young hakes are Cabrera, 1968, 1969, 1970; Bas et al., 1970). found near the coast in shallower waters than M. mer­ The horizontal distribution of sea breams is rela­ luccius. At depths between 35 and 75 m about two tively uniform, but the largest concentrations occur thirds of the stock of M. senegalensis have a total length south of Cape Juby. In the cephalopod fishery, which less than 25 cm. Below 100 m fish larger than 50 cm takes place south of Cape Garnet, the sea breams con­ constitute 90 % of the commercial catches. In the sum­ stitute the most important part of fish discard: 23 % of mer when spawning takes place, M. senegalensis the total catch in shallow waters off Villa Cisneros and migrate to deeper waters, and the main concentrations about 5 % off Cape Barbas, (Bravo de-Laguna et al., are found between 80 and 120 m. In general, M. 1977a). Between Cape Corveiro and Cape Blanc the senegalensis spawn in shallower waters than M. merluc­ sea breams are especially abundant and constitute cius. During winter, fish smaller than 30 cm are usually about 60-70 % of the commercial catches. Practically found above 40 m, while larger fish constitute 80-90 % all the species of sea breams in the CINECA region are of the catches from depths below 100 m. found in this area. South of Cape Blanc, at depths From Cape Juby to Cape Blanc M. senegalensis are down to 40 m, the sea breams represent 18 % of the regularly caught on the slope and at the edge of the demersal fish population, and from 75 down to 250 m, continental shelf between 100 and 800 m depth. North Dentex spp. only represent 43 % of the total available of Cape Bojador, juveniles are mostly found on the fish biomass. shelf at depths less than 80 m. Farther south this Bonnet (1969) distinguishes between three groups of species occurs mainly at depths of 100-400 m, but it is sea breams according to their geographical distribu­ rarely caught as by-catch in the cephalopod fishery. tion. The first one is composed of those species that Near Cape Blanc, the largest concentrations occur at occur throughout the area and whose geographical depths of about 200 m and between Cape Blanc and limits extend beyond it. A typical example of this Cape Timiris M. senegalensis is the most abundant category is Dentex macrophthalmus. The second cate­ species on the continental slope. Farther south its gory comprises septentrional species, for which the abundance decreases and it is replaced by M. cadenati. zone between Cape Juby and Cape Verde is the south­ The absolute abundance of M. senegalensis in the ern border. These are typical species of the continental area is difficult to assess owing to inadequate data on shelf and are rare south of Cape Barbas. An example catch and fishing effort. All data refer to the three of this second group is Pagellus erythrinus. The third species combined and the CECAF Working Party on category is composed of meridional or tropical species Resources Evaluation (FAO, 1975; 1976) has therefore like Sparus ehrenbergi. Their presence north of Cape not been able to make an assessment of each species Bojador is rare. separately. Domanevsky and Stiopkina (1973), how­ The migrations of sea breams in the area are closely ever, used data from quantitative trawling surveys related to the hydrological regime and its seasonal made between the Strait of Gibraltar and Cape Blanc changes. With the beginning of the cold season, start­ and estimated the total biomass to be of the order of ing in December, the northern species move to the 60000 t. continental shelf south of Cape Blanc. This movement Merluccius cadenati are distributed between approxi­ even reaches the shelf off Senegal (Domain, 1976b). In mately 28°N (Cape Juby) and 8°N, with the main the months of May and June, the waters off the north­ abundance south of Cape Barbas. From Cape Juby to ern coast of Senegal get warmer, producing a north­ Villa Cisneros the main abundance is found at depths ward movement of the septentrional species. between 500 and 600 m. Farther south the largest con­ There exists little information on the present state of centrations are found at depths from 150 to 300 m. In the stocks of sea breams. The catch statistics do not general, the vertical distribution is very similar to that give a correct breakdown by species. An assessment of of M. senegalensis. No estimates have been made on Pagellus coupei has, however, been made by the the abundance and potential yield of M. cadenati in this CECAF Working Party on Resources Evaluation. area. Other available data have been provided by quantita­ tive trawling surveys. The distribution and abundance of the main species can be described as follows: Sea breams Sparus aurata is a coastal species found down to 100 m depth from the British Isles southwards to These fishes are the most characteristic species of the Senegal (Lloris et al., 1977), in deeper waters with CINECA region. The best yields are usually obtained lower latitudes. At the coast of Casablanca, they con­ between 30 and 90 m, and up to 50 % of the commer­ stitute less than 0-08 % of the fish biomass above 20 m cial catches are taken at depths less than 90 m (Bonnet, depth (Collignon, 1971). Off Cape Bojador, and on 1969). Traditionally they constituted the most impor­ soft bottoms, the adults are abundant from 80 to 100 m tant part of the catches in this zone. Since the 1960s, (Maurin, 1968). At the last meeting of the CECAF with the increase in the cephalopod fishery, a decrease Working Party on Resources Evaluation in 1976 it was

28* 435 o □ 36° STRAIT OF GIBRALTAR

3 5°

34°

3 3 “

32° SAFI ESSAOUIRA 31*

AGADIR 3 0 “

SIDI IFNI 2 9 “

28° CABO JUBY 27.

26° CABO BOJADOR

25*

CABO LEVEN 24* VILI A CISNEROS

23*

22* CABO BARBAS

21° o CABO BLANCO 20 *

CAP TIMIRIS 19“

18“ NOUAKCHOTT 17*

16“ ST LOUIS 15* CAP VERDE n 14“ “N

Z iS parus aurata 0 -1 0 0 m I Pagellus erythrinus 0 - 1 5 0 m ^ S p a ru s pagrus 20 -1 0 0 m O Pagellus bogaraveo 150 - 4 5 0 m L J S parus caeruleostictus 2 0 - 100 m 0 Pagellus coupei 10 - 250 m

^ Pagellus acarne 10 - 4 0 0 m

Figure 284. Vertical and geographical distribution of sparid species.

concluded that S. aurata are heavily overfished in the and Angola, is very rare north of Cape Bar­ area. bas. The range of the vertical distribution and the Sparus caeruleostictus are distributed from Portugal depths at which it can be found depend on the water to Angola (Lloris et al., 1977), but are very uncommon temperature and the sea-bed quality. In general, this north of Cape Juby. The juveniles are mainly located species is found at depths between 10 and 100 m. Off on rocky grounds at depths less than 20 m. In general, the coast of Mauritania, with the exception of the the adults frequent depths between 30 and 100 m. Arguin Bank, S. ehrenbergi constitute 7 % of the Sparus ehrenbergi is a typical meridional sea bream demersal fish population between 0 and 40 m, which, although generally said to be found between (Domain, 1976a). Maurin (1968) describes the distribu-

436 o 36* STRAIT OF GIBRALTAR 1 1 1 3 5* ■ 1 1 34 RABAT ▲ : 33* 1 1 32* '

□ 1 ESSAOUIRA 200 1 i in 1 r- 1 AGADIR 30 1 1 SIDI IFNI 29° ~T ~ 1 • 1 1 23° 1 CABO JUBY 1 1 o 2 7* m i i

1 1 o 2 6* CABO BOJADOR o o CM 2 5* 30 30 -

100 . CABO LEVEN 2 4* o VILLA CISNEROS 20 20 0 o i 23*

Y 50

o 2 2 e CABO BARBAS T' o o 21* CABO BLANCO o 20 *

CAP TIMIRIS 19“ o CD 18C O NOUAKCHOTT

17*

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15* CAP VERDE □ O 14°

°N

O Dentex dentex 30-200 m O Sparus ehrenbergi 10 - 100 m ® Dentex canariensis 10-100 m H Diplodus senegalensis 0 - 1 0 0 m Dentex gibbosus 10 -150 m A Spondyliosoma cantharus 0 -1 1 0 m Dentex angolensis 50 - 200 m

Figure 285. Vertical and geographical distribution of sparid species.

tion of this species around the Arguin Bank. North of 20-30 m (Domain, 1976a). However, the vertical dis­ Cape Blanc it is very common between 60 and 80 m tribution of this species changes from season to season depth. In the northern part of Arguin it can be found depending on the hydrological conditions. At the between 30 and 50 m, off the central part between 80 to beginning and end of the warm season, it is caught on 110 m, and in the southern part from 90 to 160 m soft bottoms where spawning takes place. depth. Between Timiris and Tamxat, S. ehrenbergi Sparus pagrus is a littoral species distributed occur normally on muddy bottoms at 50-60 m, but on throughout the CINECA region, but it is especially the shelf off Senegal, they are found on rocky grounds abundant in the northern part. Off Casablanca, it con­ between 10 and 50 m, with the main concentration at stitutes 0-2 % of the fish catch at depths above 20 m

437 (Collignon, 1969; 1971). Between Cape Ghir and Cape found in the whole CINECA region at the edge of the Juby it is very common at depths between 40 and 80 m, continental shelf from 25 to 500 m. It is especially and south of Cape Bojador at 10-100 m on sandy bot­ abundant between 200 and 400 m. Below 400 m, the toms. Nursery grounds are found off A. de Cintra and females are more abundant than the males. Both males as far south as Cape Barbas at depths from 30 to 40 m. and females make frequent vertical migrations (Bon­ Boops boops is a semipelagic species distributed net, 1969). Off the southern coast of Morocco, be­ from the British Isles to Angola. It forms schools on tween Cape Ghir and Cape Juby, D. macrophthalmus rocky bottoms. Schools can also be found far from the occur mainly between 100 and 150 m on muddy coast at the surface or down to 200 m, normally above grounds. South of Cape Bojador and as far as Cape 100 m. In the northern part of the CINECA region Blanc, they are common between 50 and 300 m depth. along the coast of Morocco it is a true coastal species, Juveniles, with a length-frequency distribution close to and off Casablanca it constitutes 0-68 % of the fish 9-5 cm (mode), make up about 1-8 % of the catches in catch from depths above 20 m, 1-7 % at 20 m, and the cephalopod fishery at depths between 57 and 4-7 % at 40 m. South of Cape Ghir, at depths from 10 110 m. In the discarded catch from the Cape Barbas to 30 m on sandy bottoms, juveniles are very common. area, this species is third in importance (Bravo de- In the cephalopod fishery off Villa Cisneros, juveniles Laguna et al., 1977b). Between Cape Blanc and Cape about 11 cm (mode) are caught at depths from 13 to Timiris it is mainly concentrated at depths from 90 to 60 m and constitute on average 0-4 % of the total catch 150 m, while farther south it is also caught at 70 m, but (Bravo de-Laguna et al., 1977b). the largest concentrations occur between 200 and Off Cape Barbas at depths from 40 to 110 m, Boops 300 m. boops are taken as by-catch in the cephalopod fishery, Estimates of biomass and potential yield have been 0-4 % of the total catch. South of Cape Blanc and as far made by means of quantitative trawling surveys be­ as Cape Verde this species is found on the shelf at tween 35°N and 20°N (Domanevsky and Stiopkina, depths between 34 and 135 m (Bravo de-Laguna and 1973). They estimated the total biomass of D. macro­ Santaella, 1973). phthalmus to be of the order of 320 000 t. An assess­ Dentex canariensis is an African species that is very ment has been made by Domain (1974) for the area rare north of the latitude. The main between Cape Timiris and Cape Verde. The biomass distribution area is the continental shelf between Cape was calculated to be about 13 000 t, with a potential Bojador and Cape Verde from 10 to 100 m depth. It annual yield of 3100 t. begins to appear at Cape Garnet below 50 m. On the Dentex maroccanus have a more southern distribu­ cephalopod fishing grounds off Villa Cisneros, 0-09 % tion than D. macrophthalmus. They are known from of the total catch is D. canariensis. Off Cape Barbas at the Strait of Gibraltar to Angola on soft bottoms at depths between 60 and 80 m they constitute a higher depths between 30 and 500 m (Bonnet, 1969). They proportion of the catches. In the northern part of the become really abundant south of Cape Barbas, and Arguin Bank and southwards to Cape Verde they occur south of Cape Blanc they are of the same importance as especially between 30 and 50 m depth. As for other sea D. macrophthalmus. breams D. canariensis are also strongly overfished and Nursery areas are found between Cape Juby and their proportion in the catches is steadily decreasing. southwest of Villa Cisneros at depths above 100 m, Dentex gibbosus are very abundant south of Cape mainly between 30 and 50 m. Off Casablanca, D. Bojador, as far as Cape Verde. The juveniles normally maroccanus account for 0-01 % of the fish catch above occur close to the coast while the adults are more com­ 20 m depth. They are rarely caught between 20 and mon from 90 to 150 m depth. Off Cape Bojador, they 80m but occur more frequently at 120 m (Collignon, appear on sandy bottoms at depths from 80 to 100 m. 1969; 1971). South of Cape Ghir and as far as Cape In the fishing zones off Villa Cisneros (13-33 m depth) Barbas, they are mainly found between 80 and 150 m and Cape Barbas (57-110 m), this species constitutes depth and from Cape Corveiro to Cape Blanc in even about 0-08 % and 0-01 % of the total catch (Bravo de- deeper waters (220-230 m). Off the Arguin Bank the Laguna et al., 1977b). Nursery grounds are found main abundance is between 90 and 150 m (Maurin, southwest of Villa Cisneros at depths between 30 and 1968). South of Cape Timiris to Cape Verde they have 40 m. In general, the juveniles are always found at a vertical distribution similar to that of D. macro­ depths less than 60 m. South of Cape Blanc and as far phthalmus, with the largest concentrations at 200-300 as St. Louis in Senegal, D. gibbosus are common down m. to 90 m depth and have more or less the same distribu­ Dentex angolensis are normally distributed between tion and abundance as D. canariensis, with the excep­ Cape Blanc and Cape Verde at depths from 60 to 100 m tion of the Arguin Bank, where D. gibbosus are much (Bonnet, 1969; Domain, 1976a; Bravo de-Laguna and more abundant (Bonnet, 1969). Santaella, 1973). Off Senegal, this species is found on Dentex macrophthalmus is the most abundant and the edge of the continental shelf. Since Dentex polli widely distributed sea bream along the coasts of West Roux, 1954, is a synonym for D. angolensis Poll and Africa. This species inhabits deeper waters and can be Maul, 1953, the distribution of this species must be

438 ■ A 3 6* STRAIT OF GIBRALTAR

3 5°

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33*

SAFI 32* ESSAOUIRA 31*

AGADIR 30"

SIDI IFNI 29e

2 8 ®

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CABO LEVEN 2 4* VILLA CISNEROS

23*

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21* CABO BLANCO

20 *

CAP TIMIRIS 19“

1 8 * NOUAKCHOTT 17*

16* ST. LOUIS 15® CAP VERDE

14*

•N

A Argyrosomus regius 5-100 m ■ Umbrina canariensis 40 - 300 rm

Figure 286. Vertical and geographical distribution of sciaenids. considered to be much wider than originally thought, In the CINECA region the following species of D i­ and Domanevsky and Stiopkina (1973) refer to D. polli plodus have been reported: Diplodus senegalensis, as being caught as far north as 33°N. According to Diplodus cervinus, Diplodus sargus, and Diplodus vul­ these authors, fishes from 19 to 24 cm total length are garis. These are, in general, coastal species with little found at 175-200 m depth north of Sidi Ifni (29°N). commercial importance. From Cape Timiris to Sidi Ifni they are mainly caught at depths from 50 to 200 m. South of Villa Cisneros, D. senegalensis are distributed from Casablanca to juveniles (13-14 cm) are concentrated between 50 and Senegal. Off Casablanca at depths less than 20 m, they 75 m. For the area north of Timiris, Domanevsky and account for 1-5 to 2-4 % of the total fish catch (Colli­ Stiopkina (1973) estimated the total biomass to be of gnon, 1969; 1971). Farther south in shallow waters, off the order of 100 000 t. Villa Cisneros D. senegalensis with a length of 13 cm

439 36° STRAIT OF GIBRALTAR

3 5“

34 RABAT

3 3*

32*™ . SAFI ESSAOUIRA 31*

AGADIR 30

_ _ . SIDI IFNI 29*

28° CABO JUBY

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2 5 e

CABO LEVEN 2 4' VILLA CISNEROS

23*

22* CABO BARBAS

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2 0 °

CAP TIMIRIS 19-

18 NOUAKCHOTT

17

16'

CAP VERDE

A Octopus vulgaris 0 -1 1 0 m

A Sepia officinalis 0 -1 5 0 m ■ Loligo vulgaris 0 -4 0 0 m

Figure 287. Vertical and geographical distribution of cephalopods.

(mode) constitute about 4-7 % of the catch. Off Cape catch of the cephalopod fishery off Villa Cisneros Barbas, where fishing for cephalopods takes place in (0-1% and 0-3 % respectively of the total catch at deeper waters (57-110 m), the proportion of D. sene­ depths from 22 to 60 m) (Bravo de-Laguna et al., galensis is smaller (0-4 %). 1977b). D. sargus and D. vulgaris have a very wide geo­ D. cervinus is a sea bream in temperate waters from graphical distribution from the Gulf of Biscay to South to Senegal (Bonnet, 1969). Compared with the Africa and from the Gulf of Biscay to Senegal respec­ other species of Diplodus, this species has a wide verti­ tively. They occur mainly on rocky bottoms at depths cal distribution. Off Casablanca it may constitute 0-3 % less than 50 m. Both species are represented in the by­ of the fish catch at 20 m and 0-1 % at 40 m depth

440 (Collignon, 1969). From Cape Juby to Cape Blanc, it 250 m. Together with D. macrophthalmus this is the occurs on muddy bottoms at 80-100 m and also on most abundant sea bream in the area. Off Mauritania, rocky bottoms above 55 m depth (Maurin, 1968). they represent 28 % of the demersal fish population Pagellus erythrinus are very common in the northern above 40 m, and 24 % from 40 to 70 m (Domain, part of the CINECA region. Although the southern 1976b). They dominate the catch discarded in the limit of their geographical distribution lies beyond cephalopod fishery from Cape Garnet to Cape Blanc at Cape Verde, their occurrence south of Cape Timiris is 13 to 110 m depth. Off Villa Cisneros 9 % of the total rare (Bonnet, 1969). Normally they are found at all catch belongs to this species, with fish from 8 to 13 cm depths down to 100 m but they are also caught in in total length. The most frequent size group of the fish deeper waters (Bravo de-Laguna and Santaella, 1973). discarded off Cape Barbas is 13 cm, comprising about Off Casablanca, they represent 0-2 % of the fish catch 4-3 % of the total catch (Bravo de-Laguna et al., at depths less than 20 m. Between Cape Ghir and Cape 1977b). Noun, juveniles are common on rocky grounds be­ South of Cape Bojador as far as Cayar in Senegal, tween 10 and 30 m while the adults are found on soft the main concentrations of juveniles are found between bottoms in deeper waters (100-150 m) (Maurin, 1968). 25 and 50 m depth and the adults from 50 to 100 m. In the cephalopod fishery south of Cape Garnet (13-33 From Cape Barbas to Cape Blanc adults of P. coupei m depth) this species constitutes 0-7 % of the total are very abundant at about 220 m. catch (Bravo de-Laguna et al., 1977b). The state of exploitation of this species is relatively The catches of the different species of Pagellus have well known. Good index of abundance estimates exist not been reported separately and no information on from 1969/1970 to 1974 (Ikeda et al., 1976). The indices the stock biomass is available. The strong decline in of abundance are expressed in kg as catch per fishing yields of P. erythrinus and changes in demographic hour of Japanese trawlers (1000 to 1500 G. R. T.). The structure of the population, however, indicate that P. series show a continuous decrease until the fishing sea­ erythrinus is heavily overfished. son of 1971/1972 when a slight increase was noted, Pagellus acarne are distributed from the British Isles probably caused by more specialized fishing for this to Senegal and are common in the CINECA region. species. At the meeting of the CECAF Working Party This is the most common sea bream on the Moroccan on Resources Evaluation in 1976, the effect of the continental shelf (Bonnet, 1969), and is considered as a increased exploitation on all the sea breams was ana­ coastal species. Between Cape Juby and Cape Verde lysed. Domain (1974) estimated the biomass of P. the abundance decreases with decreasing latitudes, and coupei from trawling data, and the biomass between it also occurs at greater depths (down to 400 m) than Cape Timiris and Dakar was calculated to be 14 882 t, farther north. corresponding to a potential annual yield of about From Cape Spartel to Cantin, P. acarne are very 35001. common above 65 m. In the area of Casablanca from Spondyliosoma cantharus are distributed on the con­ the coastline to 20 m depth, this is a seasonal species, tinental shelf of the CINECA area down to 100 m and young fish from 20 to 27 cm account for 5-9 % of depth. They are especially abundant between Cape the total fish catch at 20 m, 38 % at 40 m, 14-5 % at Juby and Cape Timiris, where the juveniles are found 65 m, 11-4 % at 80 m, and finally 1-2 % at 120 m above 50 m and the adults below this depth (Bonnet, (Collignon, 1969; 1971). The larger fish, 25-28 cm, are 1969). In the cephalopod fishery at 13-60 m depth be­ mainly found between 36°N and 30°N at depths from tween Cape Garnet and A. de Cintra, young fish of 11 100 to 200 m. cm constitute about 2-1 % in winter and 5 % in spring South of Cape Juby to Cape Timiris this species is of the total catch. distributed between 30 and 300 m, but the juveniles are mainly found between Cape Juby and southwest of Villa Cisneros above 100 m. On the fishing grounds for Sciaenids cephalopods off Cape Barbas (53-110 m) this species The two species of highest commerçai value are Argy- ranks second among discarded species. Domanevsky rosomus regius and Umbrina canariensis. A. regius is a and Stiopkina (1973) estimated the biomass to be about migratory, demersal species distributed on the conti­ 350 000 t in the area between 36°N and 20°N. nental shelf from Morocco to Senegal. Its occurrence Pagellus bogaraveo is a European species that in the varies with the seasons and between Cape Ghir and CINECA region occurs only in the northern part. Its Cape Noun it is very frequent in spring and at the end southern limit is Arguin Bank, but it is rare already at of the summer at 10-30 m depth (Maurin, 1968). The Villa Cisneros. Its vertical distribution is confined to main abundance is in the area of Cape Blanc and Cape the slope of the continental shelf at 250-450 m depth. Timiris where spawning takes place. The juveniles are South of Cape Garnet, it represents 0-2 % of the total mainly found in the Bay of Lévrier and on the Arguin catch in the cephalopod fishery at 13-60 m depth. Bank. Good concentrations of A. regius are usually Pagellus coupei are distributed from the Strait of found from January to July with a maximum from Gibraltar to Cape Verde at depths between 10 and March to May (Domain, 1976a).

29 Rapports et Procès-Verbaux 441 o STRAIT OF GIBRALTAR

SAFI

ESSAOUIRA

AGADIR

SIDI IFNI

CABO JUBY

CABO BOJADOR

CABO LEVEN VILLA CISNtROS

CAUO BARBAS

CABO BLANCO

CAP TIMIRIS

NOUAKCHOTT

ST. LOUIS

CAP VfcRDL o

A Panulirus regius 5-200 m V Penaeus duroraum 0-100 m ^ Palinurus mauritanicus 150-600 m O Penaeus kerathurus 0-70 m

Figure 288. Vertical and geographical distribution of crustaceans.

Cephalopods Umbrina canariensis is especially abundant from Cape Juby to Cape Timiris. It is generally distributed The cephalopods are the most valuable demersal on soft bottoms from 40 to 300 m, but the largest con­ resource of the CINECA region and represent 40 % of centrations occur between 150 and 200 m. The the commercial catches (Domain, 1976a). The fishery juveniles are usually in shallow waters above 50 m. began in the 1960s as a consequence of the overexploi­ Southwest of Cape Juby good concentrations are also tation of the sea breams (Garcia Cabrera, 1968, 1969, found on muddy bottoms at depths from 40 to 60 m 1970; Bas et al., 1970). South of Cape Garnet, on the (Maurin, 1968). In the surroundings of the Arguin traditional fishing grounds for sea breams, intensive Bank, adults are principally found at 50 to 110 m. fishing, especially after the Second World War, pro-

442 duced a significant decrease in the catch of sea breams. The two main Loligo species distributed in the At the same time, an increase in the abundance of CINECA region are L. vulgaris and L. forbesi, the first cephalopods, particularly octopus, was observed. In being much more abundant than the second. L. vul­ fact, the yields of octopus during the exploratory sur­ garis are distributed from the surface to 400 m, mainly veys made by the Spanish vessels “Abrego” and above 100 m, and the sizes increase with depth. Indi­ “Cierzo” in 1941 and 1942 were insignificant (Navarro viduals from 43 to 45 cm are found below 100 m, while et al., 1943). Twenty years later, and during a cruise of the young individuals with less than 5 cm mantle length “Thalassa” in 1962, the octopus represented 3 % of the are only found in very shallow waters (Bas, 1975). The cephalopod catch. During the cruise of 1968, the calculated potential of this species is 37 000 t. It has cephalopods made up 30 % of the commercial catches, been considered to be underexploited and the total and the octopus 36 % of the cephalopods. Finally, on a fishing effort in 1974 was 40 % below its optimum cruise in 1968, 90 % of the commercial catch were level. cephalopods and of these 75 % octopus (Bonnet et al., 1971). At present the proportion of the cephalopods and octopus in the commercial catch is 90 % and 49 % Crustaceans respectively (Bravo de-Laguna et al., 1976). At present there are three main fishing zones for The crustacean species of commercial interest in the cephalopods: a) between Pena Grande (24°30'N) and CINECA area are: Panulirus regius, Palinurus Puntilla de Raimas (23°4'N), mainly above 50 m depth; mauritanicus, Penaeus duorarum, Penaeus kerathurus, b) off Cape Barbas, from 50 to 110 m; c) off Cape Nephrops norvegicus, Aristeus antennatus, Aris- Blanc to the south of Cape Timiris. The continuous teomorpha foliacea, Plesiopenaeus edwarsianus, and increase in fishing effort in the area has produced a Parapenaeus longirostris. In abundance and distribu­ decline in yield. The last report of the CECAF Work­ tion they vary greatly. Besides P. longirostris, which ing Party (1976) concluded that the MSY of this group has a wide distribution in the area, there are others like is 200 000 t. The fishing effort in 1974 was 85 % higher P. duorarum that are restricted to some zones. In gen­ than necessary to obtain this catch. eral, there is little information on their potential yield The cephalopod species of most commercial interest and biomass, catch, effort, fishing grounds, etc. are: Octopus vulgaris, Sepia officinalis, and Loligo vul­ Panulirus regius is distributed on rocky bottoms near garis. the coast and on the border of the continental shelf. O. vulgaris are distributed on the continental shelf South of Villa Cisneros and as far as Cape Blanc, this down to 200 m throughout the CINECA region. The lobster is very common in shallow waters between 5 largest concentrations are found from Cape Garnet to and 30 m depth. South of Cape Blanc it is located Cape Timiris. Bas (1975) has described the distribution between the coast and 40 m. It is very common be­ of O. vulgaris between Cape Bojador and Punta Pes- tween 100 and 200 m depth off Cape Timiris, and cador (23°30'N). He points out that there exists a high occurs at similar depths throughout the area, from density (50-8 %) of all sizes of octopus in shallow Cape Blanc to Cape Verde. waters between 25 and 50 m depth. Palinurus mauritanicus is a typical lobster on the The catch potential of O. vulgaris has been estimated slope of the continental shelf. Between Villa Cisneros in 1976 by the CECAF Working Party to be 100 000 t. and Cape Blanc it is normally distributed from 200 to The necessary effort to catch this quantity was reached 500 m depth. North of Villa Cisneros, the inclination of already in the period 1971/1972. In 1974 the fishing the continental slope is very slight, and the lobsters are effort was 40 % higher than its optimum level. found between 400 and 450 m, while farther south they In the CINECA area two different varieties of 5. are found from 500 to 600 m on sandy bottoms. Along officinalis coexist. These are: S. officinalis officinalis the zone of Cape Barbas the biggest concentrations are and S. officinalis hierredda. Both are distributed be­ found between 380 and 480 m. From Cape Blanc to tween Cape Spartel and Cape Verde from the coast Cape Verde they are more concentrated in shallower down to 150 m depth. Ikeda (1973) remarks that north waters and off Cape Timiris and Nouakchott they occur of Cape Blanc S. o. officinalis are most common, while mainly at depths from 150 to 300 m. farther south S. o. hierredda dominate in shallow Domain (1976a) has analysed the current state of the waters. The spawning grounds are located within the lobster resources along the coast of Mauritania. The isobath of 40 fathoms between Cape Garnet and Villa only basic data available are those presented by Mai­ Cisneros, and south of Cape Timiris (Domain, 1976a). gret (1975). From these data it can be observed that the Adults and juveniles are scattered on the shelf, but big yield (tonnes per trip) has strongly decreased. In the cuttlefish seem to concentrate in shallow waters (75- period 1963-1967 the yield of P. regius was about 13- 100 m) (Bas, 1975). S. o. officinalis are also strongly 14 t/trip. In the period 1968-1974 it dropped to 6-7 overfished. The calculated potential in the area is t/trip. Between 1963 and 1966 the catch per trip of P. 46000 t. In 1974, the fishing effort was 55 % higher mauritanicus was usually about 20 t. The first decrease than the optimum level. took place in 1963 when it dropped to 17-6 t/trip. A

29* 443 □ o 36° STRAIT OF GIBRALTAR

3 5

34 RABAT

3 3®

. SAFI

ESSAOUIRA

AGADIR 30

SIDI IFNI 29®

28° CABO JUBY

27®

2 6® CABO BOJADOR

25®

CABO LEVEN 2 4® VILLA CISNEROS

23®

22® CABO BARBAS

21® CABO BLANCO

o 20 ® CAP TIMIRIS 19“

18 NOUAKCHOTT

17'

1 6 '

CAP VERDE □

A Nephrops norvegicus 200-600 m ■ Plesiopenaus edwarsianus 400-900 m O Aristeus antennatus 100-700 m □ Parapenaeus longirostris 50-400 m 9 Aristeomorpha foliacea 200-700 m

Figure 289. Vertical and geographical distribution of crustaceans.

further drop to 13-14 t/trip for the period 1967-1973 The vertical distribution of P. duorarum is related to resulted in a significant decrease in fishing effort. the quality of the sea bed and to the hydrological condi­ Penaeus duorarum is distributed along the coast of tions. It is mainly found on sand and mud, from 70 to West Africa from Cape Blanc to Angola. Its distribu­ 100 m depth (Crosnier and de Bondy, 1967). Its verti­ tion is very much connected with the presence of rivers cal distribution strongly depends on the depth of the and littoral lagoons. North of Cape Verde, two main thermocline. Normally the pink shrimp is above the zones of concentration exist. The first one is located thermocline in temperatures from 23° to 25°C and between Cape Blanc and Cape Timiris in Mauritania salinities of 35 to 35-5 %o (Garcia and Lhomme, 1977). with a nursery area on the Arguin Bank. The second Individuals of medium and small sizes are mainly con­ zone is off Senegal between St. Louis and Cayar. centrated between 30 and 45 m depth. The males of

444 bigger sizes are usually in deeper waters while the size largest catches are made north of the 25°N parallel at of the females increases with decreasing depth. This depths between 400 and 700 m. It is especially frequent vertical distribution changes during the spawning sea­ off Medano de Aaiun and Cape Garnet (Maurin, 1968; son. Spawning takes place at sea, but the post-larval Maurin and Bonnet, 1969). stages are in fresh water. The entrance of the post­ Parapenaeus longirostris is very common along the larvae into littoral ponds and lagoons is related to the coast from Portugal to Angola. It is normally located phase of the moon and the temperature. on the lower part of the continental shelf, between 50 Fishing for P. duorarum at sea began in the area of and 400 m depth. The males are smaller than the St. Louis in 1956. Since then the fishing effort has females, and size increases with depth. The vertical increased from 80 to 2400 days at sea, standardized for distribution is closely related to the water temperature. trawlers of 350 hp. Garcia and Lhomme (1977) have It is very common between 8° and 15°C. Large concen­ applied a Schaefer model to this fishery and obtained trations are found along the coast of Morocco in April, an MSY of 600 t equivalent to 2100 fishing days. The May, and June. Off Senegal these concentrations occur maximum productivity in the zone of St. Louis, includ­ from July to September. The largest catches are made ing the littoral lagoons, is 2-3 t/square mile/year. In the along the northern coast of Morocco between Arcila zone of Cape Timiris the fishing activities are not regu­ and Rabat, below 100 m on sandy bottoms, but also on lar. The calculated MSY by the same authors for this muddy bottoms from 50 to 200 m. area is 60 t/year. South of Cape Ghir and as far as Cape Juby the P. kerathurus is very common, but never abundant concentrations are found at greater depths (350-600 from Portugal to Angola (Crosnier and de Bondy, m) and along Medano de Aaiun at depths between 400 1967). Normally it is found in lagoons and on the conti­ and 700 m. South of Cape Blanc this shrimp occurs nental shelf at depths less than 50-70 m. There is no frequently between 200 and 300 m. Solenocera mem- information about the potential yield of this species in branaceum in distribution and biology is similar to P. the CINECA region. longirostris. Nephrops norvegicus is distributed in the CINECA area between the Strait of Gibraltar and Villa Cisneros. This zone is probably the southern limit of its geo­ graphical distribution. It is found from 200 to 600 m. Maurin (1968) describes the vertical and horizontal dis­ References tribution along the Saharan coasts. Between El Aaiun and Cape Bojador it is located between 200 and 300 m, Bas, C., Morales, E., and San Feliü, J. M. 1970. Pesquerias de cefalöpodos en el Banco Sahariano. Publ. téc. Junt. Est. and south of Cape Garnet in deeper waters of 300-500 Pesca, 9: 129-151. m. No information is available on biomass and poten­ Bas, C. 1975. Distribution of Cephalopods in North West tial yield of Nephrops in this area. Africa (Cape Bojador - Punta Pescador). ICES CM 1975/ Aristeus antennatus is common in the Mediterranean K:9, 10 pp. (mimeo). Bonnet, M. 1969. Les Sparidés des côtes nord ouest Sea and the eastern Atlantic. In the CINECA region it africaines. Revue Trav. Inst. Pêeh. marit., 33 (1):97—116. is found at depths from 100 to 700 m, with Cape Blanc Bonnet, M., Duclerc, J., and Pichot, P. 1971. Nouvelle étude as the southern limit (Maurin, 1968). Off the northern sur les fonds de pêches du Banc dArguin et de ses abords. coast of Morocco it appears at 100 m and is especially Campagne de la «Thalassa», janvier-février 1971. Sei. Pêche. Bull. Inst. Pêch. marit., 203:1—15. abundant between 100 and 200 m from Kenitra to Bravo de-Laguna, J., Fernandez, M. A. R., and Santana, Rabat (Massuti, 1968). South of Cape Juby it is located J. C. 1976. Discardings of fishes in the cephalopods fishery in deeper waters (400-700 m). Between Villa Cisneros off West Africa. ICES CM 1976/K:32 17 pp. (mimeo). and Cape Blanc concentrations of juveniles appear Bravo de-Laguna, J., Fernandez, M. A. R., and Santana, J. C. 1977a. Length distributions of the fishes discarded in the from 300 to 500 m. bottom trawl fishery off northwest Africa. ICES CM Aristeomorpha foliacea has a geographical distribu­ 1977/G: 13,14 pp. (mimeo). tion very similar to that of N. norvegicus. Along the Bravo de-Laguna, J., Fernandez, M. A. R., and Santana, Atlantic coast of Morocco, from the Strait of Gibraltar J. C. 1977b. Discardings of sparids in the bottom trawl fishery off northwest Africa. ICES CM 1977/G: 12, 12 pp. to Rabat, it is found on sandy and muddy bottoms (mimeo). below 100 m. Near the southern limit of its geographi­ Bravo de-Laguna, J., and Santaella, E. 1973. Observaciones cal distribution, A. foliacea is located in deeper waters: biologico-pesqueras en el banco pesquero Sahariano. Bol. between Cape Juby and Cape Ghir at depths from 350 Inst. Esp. Oceanogr., 171:79 pp. to 600 m; from Cape Juby to Villa Cisneros, at 400-700 Collignon, J. 1969. Première note sur le peuplement en pois­ sons benthiques du plateau continental atlantique maro­ m; and off Cape Bojador, where it is especially abun­ cain. Bull. Inst. Pêch. marit. Maroc, 17:11-44. dant, at 550-700 m depth. Collignon J. 1971. Les poissons benthiques du plateau conti­ Plesiopenaeus edwarsianus can be found in the east­ nental marocain; 2ème note: le peuplement des sables côtières. Bull. Inst. Pêch. marit. Maroc, 18:11-44. ern Atlantic from Portugal to South Africa, between Crosnier, A., and de Bondy, E. 1967. Les crevettes commer- 340 and 1850 m depth. Within the CINECA region it is cialisables de la côte ouest de l’Afrique intertropical. Init. normally distributed between 400 and 900 m. The Doc. Tech., 7:60 pp.

445 Domain, F. 1974. Première estimation de la biomasse et de la Garcia Cabrera, R. C. 1975. Informe sobre la situaeiön actual production potentielle en poissons démersaux du plateau de las pesquerias en el Banco Sahariano. Bol. Inst. Esp. continental sénégalo - mauritanien entre le Cap Timiris et Oceanogr., 186: 39 pp. le Cap Roxo. ORSTOM Doc. Sei. Pêch., 53:23 pp. Ikeda, I. 1973. Rapport sur les recherches japonaises (1972). Domain, F. 1976a. Les fonds de pêche du plateau continental FAO Fish. Rep., 158: 41-45. ouest africain entre 17°N et 12°N. ORSTOM Doc. Sei. Ikeda, I., Hatanaka, H., and Kawahara, S. 1976. Observa­ Pêch., 61:23 pp. tions on Sepia egg clusters caught during commercial trawl­ Domain, F. 1976b. Les ressources halieutiques de la côte ing operations in the CECAF area. FAO Fish. Rep., 183: ouest-africaine entre 16°N and 24°N. FAO FLMAU/73/ 65-71. 007/1:45 pp. Lloris, D., Allué, C., Rucabado, J., and Bas, C. 1977. Fichas Domanevsky, L. N., and Stiopkina, M. V. 1973. The peculia­ de identificaciön de especies. Atlântico Oriental. Estrecho rities of the distribution and the first estimation of abund­ de Gibraltar a Cabo Verde. I. Or. Percomorphi, Fam. ance of the major groundfish species on the Northwest Afri­ Sparidae. Datos informativos Inst. Inv. Pesq., 3: 56 pp. can Shelf. ICES CM 1973/G:3, 10 pp. (mimeo). Maigret, J. 1975. La pêche langoustière sur les côtes de la FAO. 1971. Comité des pêches pour [’Atlantique Centre - Est Mauritanie. Pêche marit., 55 (1178): 281-285. (COPACE): Rapport de la deuxième session du Groupe de Massuti, M. 1968. Les crustacés d’intérêt commercial entre le Travail sur les mesures de réglementation des stocks dé­ Golfe de Câdiz et le Golfe de Guinée. Rapp. P.-v. Réun. mersaux. Rome, 22-26 mars 1971. FAO Fish. Rep., Ill: Cons. int. Explor. Mer, 159: 126-127. 111 pp. Maurin, C. 1954. Les merlus du Maroc et leur pêche. Bull. FAO. 1975. Fishery Committee for the Eastern Central Inst. Pêch. marit. Maroc, 2: 2-38. Atlantic (CECAF). Working Party on Resources Evalua­ Maurin, C. 1968. Ecologie ichthyologique des fonds chalu- tion. Rome, 3-6 December 1973. FAO Fish. Rep., 158:94 tables atlantiques (de la baie Ibéro-marocaine à la pp. Mauritanie) et de la Méditerranée Occidentale. Revue FAO. 1976. Fishery Committee for the Eastern Central Trav. Inst. Pêch. marit., 32(1): 47 pp. Atlantic (CECAF). Working Party on Resources Evalua­ Maurin, C., and Bonnet, M. 1969. Le chalutage au large des tion. Rome, 9-13 February 1976. FAO Fish. Rep., 183:135 côtes nord-ouest africaines. Résultats des campagnes de la pp. «Thalassa». Sei. Pêche, Bull. Inst. Pêches marit., 177: 17 Garcia, S., and Lhomme, F. 1977. La crevette rose Penaeus pp. duorarum notalis de la côte ouest africaine: Evaluation des Navarro, F. de P., Lozano, F., Navaz, J. M., Otero, E., Sainz potentialités de capture. FAO Fish. Cire., 703:28 pp. Pardo, J., et al. 1943. La pesca de arrastre en los fondos de Garcia Cabrera, R. C. 1968. Biologia y pesca del pulpo Cabo Blanco y del Banco de Arguin (Africa Sahariana). (Octopus vulgaris) y choco fSepia officinalis) en aguas del Trav. Inst. Esp. Oceanogr., 18: 225 pp. Sahara Espanol. Publ. téc. Junt. Est. Pesca, 7:141-198. Poinsard, F., and Villegas, L. 1975. Analyse de la pêche Garcia Cabrera, R. C. 1969. Pulpos y calamares en aguas del côtière au chalut dans l’Atlantique marocain. Trav. Doc. Sâhara Espanol. Publ. téc. Junt. Est. Pesca, 8: 75-103. Dev. Pêch. Maroc, 12: 37 pp. Garcia Cabrera, R. C. 1970. La pesca en Canarias y Banco Sahariano. Ed. by Consejo Econômico Interprovincial de Canarias, Tenerife, 200 pp.

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