The Marine Fish Resources of Mozambique Reports on survey with the R/V Dr Fridtjof Nansen. By Roald Sætre and Rui de Paula e Silva Serviço de Investigações Pesqueiras, Maputo Institute of marine Research, Bergen September 1979 From GEOLOGICAL-GEOPHYSICAL ATLAS OF THE INDIAN OCEAN, Moscow 1975. A.S JOHN GRIEG 1 TABLE OF CONTENTS TABLE OF CONTENTS.................................................................................................................................... 2 PREFACE.......................................................................................................................................................... 4 RESUMO DAS CONCLUSÕES........................................................................................................................ 5 1. INTRODUCTION ........................................................................................................................................... 7 1.1 Program and objectives.............................................................................................................................................. 7 1.2 General geographical description.............................................................................................................................. 7 1.3 A synopsis of the present fisheries of Mozambique ............................................................................................... 10 1.4 Previous investigations ............................................................................................................................................. 11 2. MATERIALS AND METHODS.................................................................................................................... 13 3. BOTTOM CONDITIONS ............................................................................................................................. 19 4. PLANKTON................................................................................................................................................. 22 5. HYDROGRAPHY ........................................................................................................................................ 25 5.1 Introduction .............................................................................................................................................................. 25 5.2 Wind and freshwater outflow .................................................................................................................................. 25 5.3 Characteristic hydrographic features and water masses ...................................................................................... 26 5.4 Surface currents........................................................................................................................................................ 27 5.5 Hydrographic structure ........................................................................................................................................... 27 5.6 Discussion .................................................................................................................................................................. 30 5.7 Tables and figures..................................................................................................................................................... 32 6. DEMERSAL FISH ....................................................................................................................................... 64 6.1. Species composition and distribution..................................................................................................................... 64 6.2. Biological characteristics......................................................................................................................................... 68 6.3. Abundance................................................................................................................................................................ 76 7. SMALL PELAGIC FISH .............................................................................................................................. 78 7.1 Species composition .................................................................................................................................................. 78 2 7.2 The distribution ........................................................................................................................................................ 85 7.3 Biological characteristics.......................................................................................................................................... 92 7.4 Abundance................................................................................................................................................................. 95 8. LARGER PELAGIC SPECIES.................................................................................................................... 98 9. MESOPELAGIC FISH............................................................................................................................... 101 9.1 Species composition and distribution.................................................................................................................... 101 9.2 Behaviour ................................................................................................................................................................ 102 9.3 Biological observations........................................................................................................................................... 103 9.4 Abundance............................................................................................................................................................... 107 10. DEEP-WATER CRUSTACEANS............................................................................................................ 108 10.1. Characteristics of the main species .................................................................................................................... 108 10.2 Abundance............................................................................................................................................................. 112 11. BY-CATCH IN THE CRUSTACEAN FISHERY ...................................................................................... 115 11.1 Shallow-water shrimp .......................................................................................................................................... 115 11.2 Deep-water crustaceans........................................................................................................................................ 117 12. SOME REMARKS ON THE FISHING EXPERIMENTS.......................................................................... 119 13. WHALES AND DOLPHINS..................................................................................................................... 122 13.1 Observations.......................................................................................................................................................... 122 13.2 Modern whaling off Mozambique ....................................................................................................................... 125 13.3 Discussion .............................................................................................................................................................. 126 14. RECOMMENDATIONS FOR FUTURE RESEARCH ............................................................................. 127 14.1 Current investigations and expected results....................................................................................................... 127 14.2 Recommendations................................................................................................................................................. 127 15. SUMMARY AND CONCLUSIONS.......................................................................................................... 129 16. REFERENCES ........................................................................................................................................ 131 3 PREFACE In addition to the present authors the following people have contributed to this report: Ch. 9 - MESOPELAGIC FISH, Jakob Gjøsæter Ch. 13 - WHALES AND DOLPHINS, Carl Jakob Rørvik Åsmund Bjordal has worked up the data from the pot catches. We also want to thank our colleagues both in Maputo and in Bergen for fruitfull discussions during the preparation of this report. 4 RESUMO DAS CONCLUSÕES No processamento dos resultados da expedição conjunta levada a cabo pelo navio de investigação “Dr. Fridtjof Nansen” foi utilizada toda a informação existente, incluindo a de expedições anteriores. Neste relatório está por conseguinte resumido tudo o que até à data se apurou sobre os recursos marinhos da República Popular de Moçambique. Recomendações para futuras investigações As conclusões a que se chegou levam os autores a recomendar que, no sentido de aumentar este conhecimento sobre os recursos marinhos, se realizem investigações sobre os seguintes aspectos: a) Recursos costeiros, incluindo os recifes de coral e os mangais; b) Amostragem e controlo da exploração da fauna acompanhante do camarão; c) Cruzeiros de reconhecimento do estado dos principais “stocks” localizados sobre a plataforma; d)