BLACKBURN and NELLEN: EGGS AND LARVAE IN AN UPWELLING AREA 



sardines have more gillrakers than Moroccan 

 sardines of the same size (Furnestin 1955). This 

 could signify that the mean size of organisms in 

 the diet of sardines decreases from north to south 

 along the African coast. 



Table 1 shows that abundance of anchovy 

 (Engraulis) eggs does not run parallel in time with 

 that of sardine eggs. There is a large difference 

 betvi^een the ratio of the mean numbers of the two 

 kinds of eggs on series 5 and 10, for instance, 

 although temperatures were about the same 

 (Figures 2, 4). We are unable to draw any conclu- 

 sions about changes in anchovy abundance and 

 their causes, even in the tentative ways attempted 

 here for the sardine. 



The concentration of Trachurus at the shelf 

 edge may indicate a feeding aggregation on large 

 zooplankton, such as euphausiids and large 

 copepods, which are more abundant there than on 

 the shelf (Figures 2-4). The high abundance of 

 large zooplankton sometimes extends farther 

 offshore than Trachurus, however. Some other 

 factor must help to determine abundance of Tra- 

 churus. The diet of T. trachurus and T. trecae off 

 northwest Africa is about 80% euphausiids, 10% 

 copepods, and 10% small fish such as anchovy 

 (Boely et al. 1973). Phytoplankton is sometimes a 

 minor constituent of Trachurus stomach contents, 

 however (Letaconnoux 1951; Overko 1964; S. Schulz 

 pers. commun.). 



ACKNOWLEDGMENTS 



The valuable assistance of several people is 

 noted in the text. Part of the senior author's work 

 was done at the Institut fiir Meereskunde, whose 

 generous hospitality is acknowledged. This study 

 was part of the activity of the CUBA program, 

 supported by the International Decade of Ocean 

 Exploration of the U.S. National Science Founda- 

 tion, Grant Number GX-33502, and of the Institut 

 fiir Meereskunde. 



LITERATURE CITED 



Aboussouan, a. 



1967. Oeufs et larves de teleosteens de I'ouest africain. 5. 

 Caranx rkonchus GeoflFr. St.-Hil. (Carangidae). Affinites 

 avec Trachurus trecae Cadenat. Bull. Inst. Fondam. Afr. 

 Noire, Ser. A, Sci. Nat. 29:1039-1050. 

 Ahlstrom, E. H. 



1959. Vertical distribution of pelagic fish eggs and larvae off 

 California and Baja California. U.S. Fish Wildl. Serv., 

 Fish. Bull. 60:107-146. 



Barton, D. 



1974. Upwelling events during JOINT I. CUBA (Coastal 

 Upwelling Ecosystems Anal.) Newsl. 3(5):21-27. 



Blackburn, M. 



1975. Summary of existing information on nekton of Span- 

 ish Sahara and adjacent regions, northwest Africa. 

 CUEA (Coastal Upwelling Ecosystem Anal.) Tech. Rep. 8, 

 49 p. 



BoELY, T., A. Wysokinski, and J. Elwertowskl 



1973. Les chinchards des cotes senegalaises et 

 mauritaniennes. Doc. Sci. Provis., O.R.S.T.O.M., Dakar, 

 46, 47 p. 

 Bravo de Lacuna Cabrera, J., and E. Santaella Alvarez. 



1973. Observaciones biologico-pesqueras en el banco pes- 

 quero sahariano. Bol. Inst. Esp. Oceanogr. 171, 79 p. 

 Chabanne, J., AND J. Elwertowskl 



1973. Cartes des rendements de la peche des poissons 

 pelagiques sur le plateau continental nord-ouest africain 

 de ll°a 26°N. Doc. Sci. Provis., O.R.S.T.O.M.. Dakar, 49, 

 8 p. 



CONAND, F., AND E. FaGETTL 



1971. Description et distribution saisonierre des larves de 

 sardinelles des cotes du Senegal et de la Gamble en 1968 et 

 1969. Cah. O.R.S.T.O.M., Ser. Oceanogr. 9:293-318. 



CONAND, F., AND C. FraNQUEVILLE. 



1973. Identification et distribution saisonierre de larv'es de 

 carangides au large du Senegal et de la Gamble. Bull. 

 Inst. Fondam. Afr. Noire 35, Ser. A, Sci. Nat. 4:951-978. 

 Gushing, D. H., G. F. Humphrey, K. Banse, and T. Laevastu. 



1958. Report of the committee on terms and equivalents. 

 Cons. Perm. Int. Explor. Mer Rapp. P.-V. Reun. 144:15-16. 



de Buen, F. 



1931. Clupeides et leur peche (4*' rapport). Rapp. P.-V. Reun. 



Comm. Int. Explor. Mer Mediterr. 6:289-336. 

 1937. Clupeides et leur peche (7'' rapport). Rapp. P.-V. Reun. 

 Comm. Int. Explor. Mer Mediterr. 10:317-419. 

 Demir, N. 



1963. Synopsis of biological data on anchovy Engraulis 

 encrasicolus (Linnaeus) 1758 (Mediterranean and ad- 

 jacent seas). FAO Fish. Synop. 26, 44 p. 

 Face, L. 



1920. Engraulidae, Clupeidae. Rep. Dan. Oceanogr. Exped. 

 1908-1910, Mediterr. 2, Biol. A9, 140 p. 

 Furnestin, J. 



1955. Remarques sur quelques caracteres de la sardine de 

 Mauritanie (Sardina pilchardus Walbaum). Cons. Perm. 

 Int. Explor. Mer Rapp. P.-V. Reun. 137:24-25. 

 Furnestin, J., and M. L. Furnestin. 



1959. La reproduction de la sardine et de I'anchois des cotes 

 atlantiques du Maroc (Saisons et aires de ponte). Rev. 

 Trav. Inst. Peches Marit. 23:79-104. 



1970. La sardine marocaine et sa peche. Migrations tro- 

 phiques et genetiques en relation avec I'hydrologie et le 

 plancton. Cons. Perm. Int. Explor. Mer Rapp. P.-V. R6un. 

 159:165-175. 



HUREAU, J. C, AND E. TORTONESE. 



1973. Carangidae. In J. C. Hureau and Th. Monod (editors). 

 Check-list of the fishes of the north-eastern Atlantic and 

 of the Mediterranean, Clofnam I, p. 373-384. Unesco, 

 Paris. 

 Kiliachenkova, V. A. 



1970. Development and distribution of eggs and larvae of 

 Trachurus trachurus L. Cons. Perm. Int. Explor. Mer 

 Rapp. P.-V. Reun. 159:194-198. 



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