1. INTRODUCTION

1.1 Program and objectives
1.2 General geographical description
1.3 A synopsis of the present fisheries of Mozambique
1.4 Previous investigations

1.1 Program and objectives

According to the agreement between the government of the People’s Republic of Mozambique and the Norwegian Agency for Development, (NORAD) an expedition was planned to survey the fishing potential of the waters adjacent to Mozambique with the Norwegian research vessel “Dr. Fridtjof Nansen”. The investigation was carried out from 24 August 1977 to 20 June 1978. During this time four complete coverages of the coast were performed. The program was executed by a joint team of Norwegian and Mozambican scientists.

The main objectives of the program were as follows:

1. To locate the areas of the commercially important species concentrations with special emphasis on the pelagic and mesopelagic species.

2. To map out the distribution areas of those concentrations.

3. To carry out biological studies of the commercially important species.

4. To carry out oceanographic studies in the distribution areas of those species, particularly in the commercial concentration zones.

5. To estimate the abundance of the localized stocks.

6. To evaluate the efficiency of the different fishing gears.

7. To introduce the Mozambican participants to the methods of acoustic fish stock assessment.

This report will deal with the pelagic and demersal fish resources as well as the deep-water crustaceans. An attempt at abundance estimation of the shallow-water shrimp stock is given by ULLTANG, BRINCA and SILVA (1979). Only the by-catch of the shallow-water shrimp fishery will therefore be discussed here. The present report also includes a brief description of the most conspicuous hydrographic features and some comments on whales.

1.2 General geographical description

Mozambique lies on the east coast of Africa between latitudes 10°20’ to 26°50’ South (Fig. 1.1). The coastline has a length of more than 2500 km. The Mozambique Channel which separates Mozambique from Madagascar Island is about 400 km wide at its narrowest point. In the extreme north, Cape Delgado forms the dividing point of the Southern Equatorial Current. The southward flowing branch of this current, known as the Mozambique Current and further south as the Agulhas, has a far-reaching influence on the climate and life of southern Africa.

The climate of Mozambique is dominated by two regimes. South of the Zambezi River it is characterized by the passage of the depressions of the SE Trade Wind Zone, and north of the Zambezi by the southern end of the East African Monsoon System (TINLEY, 1971). The coast receives rain in all months of the year with a maximum during the southern summer.

In the northern part of Mozambique the winds follow the alternating monsoon system with NE winds during the southern summer and SW winds during the southern winter. Central and Southern Mozambique receives easterly prevailing winds and, especially during southern summer, southerly gales can seriously affect fishing activity.

Fig. 1.1. Bathymetric map of the waters off Mozambique.

The major rivers of Mozambique (Fig. 1.1) are: Rovuma, Lúrio and Zambezi in the north, Pungué, Buzi, Gorongosa and Save in the Sofala Bay and Limpopo, Incomati and Maputo in the Delagoa Bay. All these rivers carry tremendous volumes of silt. This high silt load has an important effect on the life on the continental shelf and sandbanks occur far out to sea in Sofala Bay. At the mouth of these rivers mangrove swamps occur, these are believed to be important for the reproduction cycle of the local shrimps. In these areas there is also an exploitation of the stock of mangrove crab.

The tidal range on the Mozambican coast is one of the highest in Africa. Tidal amplitudes of more than 6 m are recorded in Sofala Bay. From this area the tidal amplitude decreases both to the south and north along the coast.

The continental shelf of Mozambique out to the 200 m depth contour is approximately 70 000 km² (Fig. 1.1). The extreme north of Mozambique is markedly different from south of the 15th Latitude. In the north the continental shelf is very narrow, only several hundred meters wide, and deeply scarred with submarine canyons and edged by corala reef. The shelf is widest at Sofala Bank off Beira. Shallow banks or seamounts are found off the coast at St. Lazarus Bank NE of Pemba, Paisley Seamount off Nacala and Almirante Leite Bank east of Maputo. The central and southern part of the shelf is mostly sand and silt with some coral patches along the Delagoa and Inhaca shores.

1.3 A synopsis of the present fisheries of Mozambique

Most of the fishing along the coast of Mozambique is of the subsistence type and is confined to the immediate coastal waters. However, over the last two decades an industrial shrimp fishery has developed and a semi-industrial fishery started exploiting the inshore fish resources.

For the artisanal fishery no official statistics are available. This fishery is carried out from small craft, 3 to 8 m in length, and includes fishing gear such as traps, beach seines and gill-nets. There are indications that the total catch of this fishery may exceed 20 000 tonnes and that its contribution to the internal fish consumption is about 80%. In addition to fish this small-scale fishery also includes some inshore shellfish and holothurians.

The semi-industrial fishery is worked mainly by small trawlers and gillnetters, 10 to 12 m long, which operate at depths between 10 and 20 m. The national industrial fishery is for the moment exclusively a shrimp fishery, and it is expected that the Mozambican fleet will fluctuate in the near future between 40 and 50 units.

Table 1.1. Total and crustacean landings of the industrial and semi-industrial fisheries during 1965-1975 (tonnes).

YEAR	1965	1966	1967	1968	1969	1970	1971	1972	1973	1974	1975	1976
Total landings	4181	5347	5047	5707	7028	7634	10423	10413	13338	15655	11486
Crustacea landings	599	1019	1037	1070	1125	1128	2554	2689	3442	6072	4339	4822
Total landings in main ports	-	-	-	-	-	-	5513	6332	9329	12628	8289	-

Table 1.1 gives the crustacean and total landings for the last 12 years according to the official statistics (ANON, 1976 b). The crustacean landings include 10 tonnes of lobster in 1971 and 1975, and 48 tonnes in 1974.

As can be seen the national shrimp production increased more than 10 times during these years and the total landings approximately four times. The lower catches following 1974 were a consequence of the disorganization after the exodus of the Portuguese personnel and the government’s new approach in giving more attention to the small-scale fishery. Landing data for 1976 are not available. Table 1.2 gives the landings for 1977. In addition there is a licensed foreign fleet which has an estimated yearly catch of about 5000 tonnes of shrimps (ULLTANG et al, 1979).

Table 1.2. Landings of the industrial fishery from different size classes of vessels in 1977 (tonnes).

Vessel type and average size		No. of units	Shrimps/Lobsters		Marine fish
			tonnes	%	tonnes	%
Stern trawler	- 16 GRT	10	125	31.7	567	82.0
Stern trawler	- 40 GRT	6	190	59.4	130	40.6
Pair trawler	- 120 GRT	24	2343	89.9	263	10.1
Pair trawler	- 360 GRT	2	485	90.3	52	9.7
Lobster trawler	- 95 GRT	1	24	77.4	7	22.6
Total		-	3159	81.4	721	18.6

The fish landings from the industrial fishery are a by-catch from the shrimp trawling. Most of this by-catch is not utilized but discarded at sea due to the small freezing capacity of the ships and lack of manpower to take care of the fish catches. Small shrimp trawlers below 40 GRT in the bays of Maputo and Beira are, however, landing all the fish caught.

Table 1.3. Total catch from the Soviet trawlers September 1977 - June 1978 (tonnes).

Species	Sofala	Bazaruto	Delagoa	Total
Demersal fish	1920	1	260	2181
Pelagic fish	3367	1	1147	4515
Mixed fish	2570	3	536	3109
Sharks - Rays	392		12	409
Total	8249	5	1955	10209

Since September 1977 some licensed Soviet trawlers have been fishing off Mozambique. Table 1.3 gives the total catch for the period when “Dr. Fridtjof Nansen” was working in the area.

A gill net fishery is carried out on kelee shad (Hilsa kelee) in the bays of Maputo and Beira. In 1977 this amounted to 916 tonnes in Maputo Bay.

1.4 Previous investigations

The first attempt at estimating the fish resources of Mozambique was made by Shomura (GULLAND 1970). They arrived at a potential annual yield from demersal resources of the shelf region of 300 000 tonnes/year. This very rough estimate depends on obtaining a reliable figure for the yield per unit area in one region and extrapolating this to another area. The method is crude with several significant sources of error, and the result should therefore be treated with caution.

In May 1975 the Polish research vessel “R/V Professor Siedlecki” carried out a cruise along the coast of East-Africa (ORLOWSKI, 1975). Unfortunately the report is only published in Polish and thus not available for the present authors.

As part of the FAO Indian Ocean Programme the “R/V Professor Measyatsev” carried out fishery investigations along the coast of Mozambique in January-February 1976. The studies were continued in August 1977. Results from the first part of the work have been published by BURCZYNSKI (1976). By using a combination of acoustic methods and catch rate he gives the size of the stock for the time of the survey as seen in Table 1.4.

Due to bad weather conditions the stock size in Delagoa Bay was probably gravely underestimated. From the same investigations BIRKETT (1978) presented some abundance estimates based on the “swept area method”. These estimates are shown in Table 1.5.

Table 1.4. Stock size in thousand tonnes January-February 1976 (BURCZYNSKI, 1976).

Area	Sofala	Delagoa	Total
Demersal fish	97	8	105
Pelagic fish	65	11	76
Total	162	19	181

Table 1.5. Abundance estimates in thousand tonnes from the “Professor Mesyatsev” (BIRKETT, 1978).

Area	Sofala		Delagoa
	Jan. 1976	Aug. 1977	Jan. 1976	Aug. 1977
Demersal fish	62.4	35.1	23.1	21.2
Pelagic fish	94.5	42.4	40.2	4.6
Total	156.9	77.5	63.3	25.8

Under an agreement between Mozambique and U.S.S.R. the Soviet trawler “Aelita” carried out fishery investigation in Mozambican waters during three periods in 1976 and 1977:

	18 June to 13 August 1976,
	30 October 1976 to 26 February 1977,
and	15 April to 31 June 1977.

After completion of each investigation period an interim report was presented.

The final report, BUDNICHENKO et al (1977), includes results from the exploratory fishing, the hydrographic investigations, and the biological studies on crustaceans and fish. It also includes estimates of total fish abundance based on the “swept area method” for the Boa Paz area, the shelf between Bazaruto Island and Ponta Zavora, and the Sofala Bank area. Table 1.6 gives the results.

Table 1.6. Estimates of total fish stock size in thousand tonnes according to BUDNICHENKO et al (1977).

Area	Time	Latitude	Fishing area (n. mile)2	Depth (m)	Stock
Boa - Paz	June - August 1976	24°48’ - 25°00’	188	20-100	6.0
	December 1976 - January 1977	24°48’ - 25°01’	161	20-100	10.6
	April - June 1977	24°54’ - 25°08’	191	20-100	13.8
Bazaruto Island - Ponta Zavora	January 1977	21°34’ - 24°42’	625	150-450	9.3
	April - June 1977	21°31’ - 21°52’	121	180-200	10.4
	April - June 1977	21°55’ - 24°47’	637	50-450	8.6
Sofala Bank	June - August 1976	16°47’ - 19°25’	2915	17-100	29.9
	October - December 1976	17°23’ - 19°38’	3553	17-100	77.9

From 2 October to 12 December 1977 the trawler “Kattegat” from the German Democratic Republic carried out fishery investigations in Delagoa Bay and at the Sofala Bank (ANON, 1978 e). A total of 188 trawl stations were carried out mainly using shrimp or bottom trawls. This investigation concentrated on fishing and gear techniques.