THE UNITED REPUBLIC OF TANZANIA

REDUCING THE IMPACT OF TROPICAL SHRIMP TRAWLING FISHERIES ON LIVING MARINE RESOURCES THROUGH THE ADOPTION OF ENVIRONMENTALLY FRIENDLY TECHNIQUES AND PRACTICES IN TANZANIA

By W. V. Haule; National Coordinator (Fisheries Division; Ministry of Natural Resources & Tourism; P. O. Box 2462; Dar Es Salaam; Tanzania; Fax: 255-51-110352; E-mail: [email protected]).

1. INTRODUCTION

Tanzania lies South of the equator between 10S - 110 45'S and 290 21'E - 400 l5'E and is the largest country in East Africa. It has a coastline of about 800-km of the Indian Ocean, which covers five administrative regions namely Tanga, Coast, Dar Es-Salaam, Lindi and Mtwara. The coast has a narrow steeply falling continental shelf estimated to be about 17 500 km². The continental shelf is about 5.8 km, except the Zanzibar and Mafia channels where the continental shelf reaches a width of about 62-km.

The fisheries are y2859ely artisanal, producing about 85% of the annual fish landings, concentrated close to the shore due to the limited range of the craft at the disposal of the fishermen.

About 2% of the population is engaged in fishing along the coast. The marine fisheries employs about 15 000 artisanal fishermen operating with a total of about 3 200 fishing vessels (mostly canoes) and landing an average of 36 700 tonnes of fish and about 700 tonnes of prawns per year. Both, artisanal fishermen with small crafts and industrial prawn trawlers participate in the harvesting of the marine resources, especially in prawn fisheries. The small-scale fishermen only fish in the very shallow waters (less than 3 m deep) while trawlers fish in areas ranging from the coast to more than 20 m deep. Fish contributes over 60% of protein consumption of the coastal population. Coastal communities depend on fishing as their y2859e source of income.

Available marine fish resources are not well known. The fishery resources surveys carried out by the Norwegian research vessel R/V Dr. FRIDTJOF NANSEN in 1982/83 estimated the standing stocks of marine fishes in waters over 20 m depth to be between 100 000 and 175 000 tonnes. The potential yields were estimated to be between 25 000 and 44 000 tonnes per year. The catch composition of fish during the trawl surveys consisted of small pelagic, y2859ely sardines, carangids, scombrids, silver biddies and prawns. Annual yields as estimated by FAO (1984) were about 38 000 tonnes/year for demersal species and about 23 000 tonnes for pelagic species, such as sardines and small tuna. This gives an overall estimate of 60 000 tonnes per year for commercial marine fish resources for the territorial waters.

The Artisanal fisheries in inshore shallow waters produce about 85% of the annual fish. The productive fishing grounds include coral reefs, sea-grass beds and reef flats. These areas experience very heavy fishing pressure and show now signs of over exploitation.

The demersal fish species auch as . breams, groupers, parrotfish, snappers, rabbit fish, emperors, sharks and rays dominate the marine catches. These are caught using hand lines, traps and nets. The small pelagic fishes consist primarily of sardines, small tuna and mackerel. These are caught y2859ely using purse seine nets or ring nets. Large pelagic, such as kingfish, tuna, sailfish and marlin are caught by surface gillnets and trolling lines. Other species include octopus and lobsters, which are usually hand collected from reef flats at low tide by divers. Sea cucumbers and cockles are caught using trawl nets hand lines, seine nets set nets, etc. Prawns or shrimps are caught in estuaries by shrimp trawlers or with seine nets.

2. THE SHRIMP FISHERY

2.1 Shrimp Resources

Five penaeid species contribute to the Tanzanian shrimp fishery. The white prawn Penaeus indicus makes up to 66% of the catch, 18% are giant prawn Penaeus monodon and the tiger prawn Penaeus semisulcatus, 15% are brown shrimp Metapenaeus monoceros and the flower shrimp Penaens japonicus makes up 1%.

The maximum sustainable yield i.e. potential annual catch has been estimated for shrimp at between 1 050 and 1 400 metric tonnes.

The shrimp fishery is located in three major areas namely Bagamoyo area extending from 050 30'S to 06O 30'S; Kisiju area from 07O 05' to 07O 45'S and Rufiji area from 08O 00' to 08O 40'S (Figure 1).

Kisiju area is the most productive shrimp fishing ground, contributing 45% of the annual catch. Bagamoyo fishing ground contributes 25% and Rufiji area contributes 30.% of the shrimp annual catches.

The Bagamoyo area is fed by freshwater from the Pangani, Wami and Ruvu rivers (Figure 1). Tributaries from the Rufiji River (Figure 1) feed the Kisiju and Rufiji areas. The peak outflows of these rivers occurs between March and May, with the exception of Pangani which has a constant run off, accompanied with shrimp peak catches during the months of April, May and June. The fresh water outflow of these rivers is very much restricted to the inshore waters during the South west monsoon (which lasts from April to October) because the wind blows from the south parallel to the coast and thus deflects water to the left piling it up along the coast (Ekman transport) (Iversen et al, 1984).

Figure 1. Shallow-water shrimp fishing grounds and surveyed areas off the Tanzanian coast

2.2 Fishing methods and practices

2.2.1 The Artisanal shrimp fishery

The dugout canoe, locaaly known as mtumbwi is the most commonly craft in use in small-scale fisheries; it is propelled by oars and poles or, if operated in the open waters, occasionally equipped with sails. Planked boats equipped with sails and/or outboard engines are employed as well.

"Mesh nets" and seine nets are the predominant gears. Both mesh nets and seine nets are made of nylon yarn with mesh sizes ranging from 1 to 2 inches and 1/16 to ½ inches respectively. Mesh nets are usually two ply and the seine nets range between six and eight ply.

There are two types of "mesh nets" with different mean lengths of 113 yards (103 metres) and 378 yards (344 metres). The former is y2859ely operated from dugout canoes while drifting with one end attached. The latter is set across channels within the inter-tidal zone. "Mesh nets", held between two mangrove poles are frequently towed by two persons operating on foot.

Other nets very similar to the above mentioned ones, small seine nets locally known as "chandalua" or "tandio", 10 and 20 yards (9 and 18 metres) long, are also very common; larger seine nets, "nyavu" are often more than 50 yards (46 metres). Such seine nets are most of the time operated by two persons either on foot or with a dugout canoe. Wooden bars are attached at each end and the fishermen drag the nets in the shallow waters during low tide.

Fishing methods also include cast-nets, beach seines, lift nets and mosquito nets. The use of pots is reported in some areas, whereby maize and rice husks as used as a bait.

Mosquito nets ("chandarua/tandio") which are somewhat similar in design to beach seines although made of mosquito netting and generally much shorter in length, are commonly used by women for seining in the shallows during low tide.

Various forms of traps are set on the seaward side of the inter-tidal zone for trapping shrimp during the outgoing tide: - "uzio", which are fixed trap consisting of long fenced screens made from poles cut from mangrove trees, narrowing into a gate - way leading to a catch chamber; - "wando", another fixed trap similar to the "uzio" but made of manufactured materials such as wire mesh or nylon netting. Another type is "utanga" which is a barrier made of mangrove poles used in the small creeks and channels at the edges of the mangroves.

2.2.2 Industrial shrimp trawl fishery

The Gear

Floridian rigging commonly known as double rigg trawling or outrigger trawling is the predominant method used by shrimp trawlers: two similar trawls are towed at the same time, one of each side of the vessel. More than 80% of the trawlers use the 4 seam semi-balloon net designs. The net webbing material for the body of the shrimp trawls is PE 360d - 400d/3. The wings and the body have mesh sizes ranging from 50 to 55 mm. Most vessels shoot a try-net before shooting the standard shrimp trawls. The try-nets have 3-5 metres head rope and are used with miniature otter boards of 0.3-0.6 metres. Most of the trawlers use rectangular, flat, wooden, otter boards .

The boards are directly attached to the wings. Four chain bridles are then used to attach the otter board to a wire bridle that runs to the y2859e towing warp. The bridles are, in general, 16mm in diameter and 60-70 m in length. The y2859e warps are 18-20 mm diameter wires. Eighty five percent of the trawlers use combination wires for their ground ropes, sizes ranging from 16-18 mm in diameter. The rest use steel wire covered by PP rope.

Ballasting is done by chain. Short link chains are used to tie loops along the ground rope at 30-45 cm intervals. The loops constitute 9-12 links of chain. The fleet popularly uses tickler chains.

There are no by-catch reduction devices on the trawls.

The vessels

The majority of the shrimp trawlers are double rig, outrigger trawlers. The outriggers/booms are normally made of steel and are 8-12 metres long. The side booms, center boom and center mast are located at mid-ship. The vessels are usually single-decked with crew quarters in the fore body and fishing activities being carried out on the y2859e deck in the aft.

Color video sounders are popularly used as a fish finder on the vessels. All trawlers carry SSB and VHF radios. The vessels have no shrimp sorting machines. Almost all vessels possess blast freezers and freezing hold. The holding temperatures in the fish hold range from -21oC - 35oC.

Most of the time, the vessels operate within 1-6 nautical miles from the coast at depths ranging between 3 and 20 metres.

The engine power of the vessels is ranging from 220 HP to 992 HP and the lengths from 17.6 to 38.1 m while the Gross Registered Tonnage is between 45 GRT and 296 GRT.

To date the engine horsepower has been by regulation limited to not more than 500 HP and and the Tonnage of the shrimp trawlers not more than 150 GRT.

Table 1 gives vessels specifications that have been operating over the years.

The shrimp trawlers operate within 1-6 nautical miles from the coast at depths of 3-20 metres. The vessels are rationally divided into three groups and made to fish on the three fishing grounds (Figure 1) on monthly rotational basis.

Both industrial and artisanal fisheries share the shrimp resource in the same waters.

2.3 Effort data by fishing method

A shrimp Fishing Unit (SFU) is defined as the combination of fishing gear, crew and often although not always, a fishing boat, targeting the shrimp stock on the shallow water fishing ground. The annual mean number of fishing days per SFU in the Tanzanian artisanal fishery is about 250 days but the number of Shrimp Fishing Units and catch rates are still to be studied in detail.

However, SWIOP/MNRT made some survey of the artisanal shrimp fishery in 1990. The estimate was some 859 Shrimp Fishing Units , with annual mean number of 160 fishing days per SFU .

The Fisheries Division mentions 250 fishing days per year in the artisanal fishery statistics.

Regarding the catch, a serious discrepancy is observedbetween the SWIOP/MNRT estimate, in 1990, for the annual catch of 1 923 tonnes for shrimp (all species) and 1,121 tonnes for the white and tiger shrimp while the official statistics of the Fisheries Division give the shrimp catch by the artisanal fishermen as 536 tonnes (1988) and the exports as 247 tonnes.

Table 2 gives the number of shrimp trawler, number of fishing days and shrimp and fish catches over the years.

The number of shrimp trawlers had a pick in 1995; it was 17 in 1998 and in 1999, the number to licensed shrimp trawlers during standed at 20.

This number of shrimp trawlers is likely to increase in the years to come.

2.4 Shrimp catches

Commercial trawling for prawns in the Tanzanian waters commenced in 1969 after an exploratory fishing survey carried out by a Japanese trawler from June to December 1968 but the shrimp trawl fishery y2859ely developed after 1982 with the acquisition of trawlers by the parastatal organization - Tanzania Fisheries Company (TAFICO).

TABLE 1: Vessel Specification

N/A Data not available

TABLE 2: Number of shrimp trawlers, fishing days, shrimp catches and fish catches over the years

Licensing of foreign trawlers was as a result of policy liberalization of the national economy in mid 1980's. Thus licensing of foreign trawlers began in 1987. Three (3) foreign trawlers were licensed in 1987. More substantial influx of foreign trawlers occurred in 1988 and has increased in subsequent years.

Aseady mentioned, the number of operating vessels in 1998 was 17 and, in 1999, 20 shrimp trawlers have been fishing in the Tanzania waters.

The catches of shrimp and fish resulting from the effort by trawlers during the period 1988 - 1998 is given in the Table 3 below.

TABLE 3. Shrimp and fish catches (in tonnes) by trawlers during the period 1988 - 1998

The shrimp species from the industrial fishery are

There has been a variation in the percentage species composition according to different reports.

According to surveys in 1985 and 1990, the percentage of P. indicus would vary between 60 and 65.9%; P. onodon would be around 15% and P. semisulcatus 4% or in another report P.monodon and P.semisalcatus together would be 11%; the percentage of Metapenaeus monoceros would be 15 to 20%; finally P. japonicus would be 1 to 7% (Concerning this species, it was observed that it consisted y2859ely in small sized individuals, making insignificant contribution to the total catch and suggesting some over exploitation of the resource).

In the artisanal fishery the shrimp species composition is influenced by the gear type and fishing location. The proportion of white shrimp (Penaeus indicus) is greatest when using "mesh nets" that are y2859ely operated either in the inter-tidal zone or river mouths. The proportion of small shrimp is greatest when using fixed traps such as "uzio" or other that are set along the outer edge of the inter-tidal zone. The smaller the mesh size, the greater the catch rate, and the greater the proportion of the small shrimp categories.

2.5 By-catches

2.5.1 By-catch rates; its utilization

An analysis of the trawl total by-catches showed that the highest, 116kg/hr, were in the north (Bagamoyo area) and 85kg/hr further south, in Kisiju area (Figure 1).

The species composition of the by-catch and its possible utilization was studied by Nkondokaya (1992).

2.5.2 Shrimp to by-catch ratio

The shrimp to by-catch ratio vary widely from one haul to the other, between areas and period of the year. As already mentioned, there is more by-catch in the north and, consequently, t he shrimp to by-catch ratios are much higher in the Kisiju area than in the Bagamoyo area, with averages of 1:3 to 1:4 in the former against averages of 1:9 to 1:14 in the latter. In both areas there is a general decrease in ratios towards the end of the year.
The observed difference in shrimp to by-catch ratio between the two studied areas may be due to variation in environmental factors. Three rivers flow in the Bagamoyo area whereas the Kisiju area is fed by one river only but having a number of tributaries. Run-off difference is likely to cause difference in salinity, nutrients input and bottom types. These factors are important for the distribution of both shrimp and finfish.

In Tanzania, the seasonal character of catch, although not documented in details, seems to exist. There are two monsoon seasons, viz. the Southwest and Northeast monsoons that last from April to October and November to March respectively. During the Northeast monsoon (November - March) temperatures reach high levels, the wind speed is low and consequently the sea is calm. During the Southwest monsoon (April - October) air temperature is low, the wind is strong and the sea is rough. Heavy rains, which result in more freshwater and organic matter influx occur between March and May. These factors are likely to have an influence on the seasonal character of catch for shrimp and finfish.

2.5.3 Total by-catch

In 1989 and 1990 the Bagamoyo area had a larger total by-catch, whereas in 1991 a slightly larger by-catch was caught in Kisiju area.

The total by-catch estimates covering the years 1989 and 1990 were extrapolated using shrimp to by-catch ratio for 1995, assuming the ratio had rey2859eed constant throughout the years (Figure 2). This is likely to give a biased estimate. The figures should therefore be considered with caution.

2.5.4 Fish discarded

The amount of fish being discarded varies according to fishing areas and there are fluctuations from year to year. In 1989 and 1990, larger quantities of by-catch were discarded in the north, whereas in 1991 there was more discarding in the central area (Kisiju).

By-catch discarded

The main reason for discarding fish by the trawlers is their low value relative to shrimp. Because of this

- a small percentage of the by-catch is kept in the limited freezing space, particularly during the shrimp peak season
- the majority of the crewmembers are assigned to the processing of shrimp while just few members process the bulk of the by-catch.

Economic considerations overrule the high protein demand that the fishery could satisfy with some of the by-catch . Selling the by-catch at sea (which is possible) could increase the returns and make the fishery more profitable.

The major by-catch species: Trichiurus lepturus, Hilsa, kelee, Pellona ditchela, Thrissa, vitrirostris and Leiognathus leuciscus are all discarded. Generally all the small pelagic species are discarded , as well as the fishes of the family Leiognathidae. On the other side, Otolithes ruber, Johnieops sina, Terapon theraps, Sphyraena obtusata and Gerres filamentosus are kept.

More rare species, which are normally kept, are Carangidae, Haemulidae, Serranidae, Nemipteridae, Lethrinidae, Lobotidae, Scombridae, Sillaginidae, Arridae and Muraenesocidae, sharks and rays (see Annex 1 for the species in these families)

Large volume of discards observed in Bagamoyo area is possibly due to relatively higher proportion of the by-catch than in Kisiju area. Because of low shrimp catch rates in the north (Bagamoyo area) one would expect that more fish is kept. This is not what is observed. Even when some space is available in the fish hold, most of the by-catch is being discarded (Figure 3). This is done purposely so that the vessel can sail to another fishing zone (Kisiju) without coming to the port for landing fish and thus saving time, fuel and port charges.

A collect of the by-catch by local boats residing in the vicinity of shrimp fishing grounds is being done as an option for increasing the utilization of the by-catch and therefore, reducing the wastages, in general. In some cases the terms of payment is through exchange of food provisions by the local boats with fish. The sale of by-catch at sea is done through authorized fish collectors.

2.5.5 Species caught

Nkondokaya (1992) identified around fifty fish species caught with shrimp in Bagamoyo and Kisiju areas. (Annex 1). Sixty one percent of the total species caught were common to both areas.

In both areas, the demersal brackish water species consisted of the large head hair tail Trichiurus lepturus, the tigertoolh croaker Otolithes ruber, the sin croaker Johnieops sina, the catfish, Arius sp. the bearded croaker Johnius dussumieri and the blackspot threadfin Polynemus sextarius. The smaller pelagic species consisted of the orange mouth anchovy Thryssa vitrirostris, the Indian pellona, Pellona ditchela and the kelee shad, Hilsa kelee.

The observed species composition indicates a large representation of demersal species. However there was a frequent occurrence of small pelagic species (Thryssa vitrirostris, Pellana ditchela and Hilsa kelee) in the catch. It is possible that during the day time small pelagic fish concentrate near the bottom.

Although there are more than 50 species in both Bagamoyo and Kisiju areas, some species are found to be in one area only. Leiognathus leuciscus, Secutor insidiator, Gerres filamentosus, Sphyraena obtusata and Fistularia petimba are mostly caught, around 9 deep, in Bagamoyo where the bottom is sandy. In Kisiju area, where shallower waters and on muddy bottom, the species are different.

2.5.6 Species association

In the north (Bagamoyo area), 4 groups of species were identified:

Group 1 is characterized by species known to prefer muddy bottoms. The most dominant species are Johnieops sina, Trichiurus lepturus, Otolithes ruber and Arius thalassinus. The preferred depth range is 5-7m

Group 2 is characterized by small pelagic fish (Pellona ditchela, Hilsa kelee, and Thryssa vitrirostris) associated with a demersal one Polynemus sextarius. The preferred depth range is 5-10 m.

Group 3 includes among other Leiognathus leneciscus, Sphyraena obtusata, Gerres filamentosus, Terapon theraps and Secutor insidiator. These are species of relatively deeper waters that prefer sandy bottoms (Bianchi, 1985). The preferred depth range is 6-12 m.

The other species form an un-defined forth Group.

In the Kisiju area, the study did not give well defined species assemblages (Nkondkkaya, 1992)

2.6 Distribution of catches

2.6.1 Artisanal fishery

Around 50-60 percent of the quality fish and 31 percent of the other fish are auto-consumed (SWIOP/MNRT 1990). The rest are either smoked or dried for local markets. Small bony fish are preferred as dried product rather than in fresh form, while the fishermen themselves (in the absence of local buyers) often eat larger fish fresh.

Almost all the white and tiger shrimp are sold as fresh product. The small shrimp are often either auto-consumed or dried or smoked for local products.

The shrimp are sold to shrimp collectors who transport them in iceboxes, often made of local wood covered with metal, polyethylene or fibber-glass sheeting. The wooden boxes are insulated with cork. The duration of a collecting trip is about five days. Collecting operations become more difficult during the inter-rain period because of the unfavorable weather and sea condition.

The shrimp production from the artisanal fishermen is exported to more than 27 countries. Some 60 percent are destined to the African region; the rey2859eing percentage of the exports is destined to Singapore, Mauritius, United Kingdom and Italy.

2.6.2 Industrial fishery

Catches from the industrial trawlers are processed on board, including sorting by species and commercial size, grade, packaging into 2kg boxes and freezing. Most exports are made to the European Union countries and Japan

The by-catch is sold to fish collectors at sea or auctioned at open market at Dar Es-Salaam port, after a fishing trip, which usually lasts for about 30 days. However, logistics involved in collecting the by-catch at sea is a limiting factor. Transport costs are high

3. REGULATIONS AND MANAGEMENT MEASURES

The legislation on fisheries resources conservation is contained in the Fisheries Act No. 6 of 1970 and its Principal Regulations of 1989.

The Fisheries Act. No. 6 of 1970 concerns exploitation and conservation of the fisheries resources in the jurisdictional waters (including both Territorial and the Exclusive Economic Zone) of the United Republic of Tanzania (URT).

The Law empowers the Minister responsible for fisheries to make such regulations as:

• Prohibiting or restricting the use of explosives, poisons and toxic substances for the purpose of fishing

• Prohibiting or restricting fishing (by whatever means) for immature fish

• Preventing obstruction and pollution of jurisdictional waters

• Providing for protection of Territorial waters

• Prohibiting, regulating or controlling the activities of foreign fishing vessel(s) within jurisdictional waters, and

• Establishing marine parks, sanctuaries or reserves for any purpose whatsoever.

The Fisheries Principal Regulations, 1989 of the Fisheries Act No. 6 of 1970 provide and empower the Director of Fisheries to make, introduce or attach conditions on the fishing license that deem necessary for the purpose of management and conservation of the fisheries resource. By law, the Director of Fisheries is the Licensing Authority. The licensing Policy recognizes that prawn resources being biological entities are finite and hence limited.

Management actions aimed at the conservation of the prawn resource include:

• Limitation on the number of vessels

• Limitation of the engine power to 500 HP and the Gross Registered Tonnage to 150 GRT

• Prohibition of trawling between 6.00 p.m. and 6.00 a.m .(No night fishing)

• 3 zones delimited where vessels are assigned to fish designated in on monthly rotational basis

• Closed season from December to February

• Minimum cod-end mesh size

(a) Limitation of number of vessels

The objectives are the attainment of the maximum sustainable yield (MSY) and the maximization of foreign currency earnings. In deciding the number of vessels to be licensed, the MSY is presumed to be between 1 000 and 1 400 tones, as put forward in a joint exercise involving the Fisheries Division and the FAO Project (RAF/87/008) .

(b) Engine power limitation

Licensing of trawlers is restricted to engine power of not more than 500 HP. The objective is to minimize environmental damage. The vessels are thoroughly inspected before license is granted.

(c) Prohibition of fishing at night

These gives "breathing time" to the environment and give a chance to other groups of fishermen to exploit other resources present in the area. This rule has a great socio-economic impact because it minimizes conflict between small-scale fishermen and the industrial fishery.

This rule gives also a chance to marine turtles to reach the beaches at night for laying their eggs. Anyway, fishermen are called upon to set sea turtles free whenever they are caught in their trawls or other nets.

(d) Zoning and rotation of vessels on fishing grounds

The objective is to evenly spread the effort over the fishing grounds.

(e) Closed season

The closure of fishing from December to February aims at protecting the young recruits. The months of December to February are a period of most intense recruitment.

(f) Minimum cod-end mesh size

The introduction of a minimum cod-end mesh size is being considered as a means of allowing the small shrimp to escape capture. The underlying presumption is that greater yields could be achieved by re-capturing them when they are larger. In practice it is possible that such a requirement may prove being ineffective in allowing escape; for instance, when the meshes became clogged with debris such as weed or mud. Cod-ends for industrial shrimping should not be less than 50 mm stretched mesh size.

Other management measures of the shrimp trawling industry include:

Retention of fish by-catch

It is specified to shrimpers that all the fish caught is to be retained on board the vessel for local market.

Observers

A licensed fishing vessel may at any time be required to accommodate an observer. At any one time, there is an observer in each of the fishing ground who is able to communicate with the other fishing vessels in the area.

Catch statistics

All fishing vessels are required to submit fisheries statistics including catch effort data, fishing locations, etc. on special forms which have been designed for this purpose.

Licensing

For a vessel to be granted fishing rights, three licenses are required: one for the fishing vessel itself, the second for shrimp fishing and the third for finfish harvesting.

4. RESEARCH ACTIVITIES (PAST AND PRESENT)

The Tanzania Fisheries Research Institute (TAFIRI) has conducted a survey on the prawn fisheries of Tanzania. The aim of the survey was to analyse the the composition of the catch and by-catch. It is observed that most of the catches include both juvenile of prawns and fish. The juvenile prawns are always thrown over-board as they do no fetch good market. Off the fish by-catch, the crew members usually keep a small portion of it, y2859ely table fish and, as room to keep prawns is needed, the rest of the by-catch is discarded.

The survey carried out confirms that a good percentage of prawns caught by trawlers are sub-adults and most of the small fishes are either juveniles or considered trash (while they are consumed by local communities). The report recommends the use of "fish rejection/excluder devices" that should separate prawn from fish and allow small fish to escape.

Very little work has been done on such devices for the Tanzanian shrimp trawling fisheries. The ratio of by-catch/shrimp mixtures is high. Separation of shrimp from fish is still a problem to the trawlers. Separation is done manually on deck and hence time consuming with some risk that prawns be spoiled before a long sorting..

However, the Tanzania's Mbegani Fisheries Development Centre carried out some studies on prawn selectivity by applying a large separator panel with two cod-ends.

Results showed that there was a drop of up to 30 percent of the total fish by-catch. The prawn catch was also low comparatively (no figures available). Some fishes (especially the pony fish Leiognathus spp. managed to filter along side the prawns.

A study carried out by Nkondokaya (1992) is perhaps the only comprehensive research on the by-catch in the Tanzanian shallow-water shrimp fisheries. The pilot study was carried out with the following objectives:

• estimate the quality of the by-catch taken by the shrimp fleet during the study period;
• estimate the shrimp to by-catch ratio;
• estimate the quantity of fish discarded, on the basisof the shrimp to by-catch ratio, the catch statistics of shrimp and the fish which is landed;
• determine patterns of species association in the catches, based on the sampled trawl hauls;
• determine the species composition in the catch and by-catch and the species relative importance by weight, numbers and frequency of occurrence;
• estimate the level of mortality for selected by-catch species;
• suggest sampling methods, which could improve the monitoring of the by-catch.

5. IMPACT ON THE SHRIMP RESOURCES OF PRESENT EXPLOITATION PATTERN

Both artisanal and individual fisheries share the same shallow water prawn resource.

In the artisanal fishery small mesh size nets and mosquito nets are used. It is evident that the smaller the mesh size, the greater the catch rate and the greater the proportion of the shrimp in the catch. SWIOP/MNRT (1990) estimated that annual catch for shrimp (all species) was at the tune of 1 923 tonnes and the white and tiger shrimp contributed 1 212 tonnes to the total. The contribution of small shrimp was, therefore, 711 tonnes. These estimates were greater than anticipated, because the official statistics of the Fisheries Division, in 1998, evaluated the shrimp catch by the artisanal fishermen tos 536 tonnes () and the exports to 247 tonnes.

Artisanal fishermen are known to operate with small mesh size nets either in the inter-tidal zone or river mouth areas that are nursery grounds for the small and otherwise immature shrimp. Juveniles are abundant in these areas. The use of small mesh size nets is likely to reduce the catch of shrimp at first maturity. This reduces the opportunity of catching mature and big sized prawns that would fetch higher prices.

The catching of small prawns reduces the size of the following population.

In respect to the prohibition of night fishing, it was mentioned above that it was introduced as a contribution towards minimizing the conflict with the artisanal fishermen operating on the same grounds. It was however observed that, in Madagascar, (nearby to Tanzania) the catch rates applying to both larger and brown shrimp (but not the white shrimp) are highest at night time, and it is only during the early months of each season that fishing occurs during the day time. This would suggest that there is a component of the shrimp resource i.e. the tiger which is not fully exploited.

However, the experience gained over the years after the introduction of the industrial shrimp trawlers has shown that there is no room to expand the fishing effort because the stock would not sustain it.

6. IMPACT ON FISH RESOURCES OF THE PRESENT SHRIMP EXPLOITATION PATTERN

By-catch Reduction Devices are not used in the industrial trawl fishery. All the fishes that are in the trawl net are caught. Few of the fishes are retained on board, but the major part is discarded dead. In this way industrial trawl is wasteful of the fisheries resources.

Since the beginning of the trawl fishery, artisanal fishermen have observed a reduction in their catches: Less fish would be available for the artisanal fishery because of the wasteful practices of the trawl fishery with large discarding.

The rate of depletion of fish resources from the trawl fishery is greater than that from the artisanal fishery.

Based on the literature, some of the species caught and discarded e.g. Johnieops sina, Terapen theraps, Gerres filamentosus and Leiognathus leuciscus are small predators feeding on juvenile shrimp (and other bottom invertebrates).

Considering that:

• The rate of depletion of the fishes including the shrimp predators from industrial trawl discards is high.

• The greater population of the small shrimp category results from the use of small mesh size gear in the artisanal fishery.

Then the declining population of the fishes as a result of trawl fishery is left with declining juvenile shrimp to feed on. This is likely to have a reduced rate of the fish population reproduction as a result of reduced juvenile shrimp food.

7. THE IMPACT ON NON- FISH BY-CATCH OF PRESENT FISHING PRACTICES

Non-fish by-catch of economic importance caught from shrimp trawling fishery include:

Crabs: y2859ely Scyla serrata,

The major part of the crabs captured by the shrimp trawlers are discarded, some dead, other alive.
Other crustaceans, some of the big sized Scilla serrata, are eaten on board.

Cephalopods: - Cuttlefish: Sepia pharaonis, the Pharic cuttlefish and S. prashad, the hooded cuttlefish. - Squids: Loligo duvauceli, the Indian squid and L. forbesi, the veined squid

All these cephalopods, squid and cuttlefish, are retained on board for consumption. Their magnitude is not of sufficient quantity to warrant them sale at fish markets.

Turtles: Five species inhabit the Tanzanian marine waters. These are:

Caretta caretta, the pacific loggerhead turtle
Chelonia mydas, the Pacific green sea turtle
Eretmochelis imbricatta bissa, the hawkibill turtle
Lepidochalis olivacea, the Pacific ridley turtle and
Dermochelys corriacea schlegelli, the pacific leatherback turtle

The sea turtles have occasionally been cited as caught in trawls, few dead but, most of them, alive. Sea turtles are protected by law and fishermen are called upon to set sea turtles free whenever they are caught. This seems to be the practice.

Non-fish resources, not of commercial importance that make way into trawls include, every now and then, sea-urchins, bivalves, worms and some other benthic organisms and discarded . For these organisms, which arrive dead on the deck, no potential utilization has been found and these are, therefore, discarded.

8. THE IMPACT ON THE BOTTOM HABITAT OF PRESENT FISHING PRACTICES

Tickler chains are attached to the groundrope of trawl nets, dragged over the sea bottom to drive shrimp into the codend.

The nature of the bottom habitat differs according to fishing grounds. Bagamoyo fishing grounds have a sandy bottom seabed. Kisiju and the rest of the southern area have a muddy bottom because of a high siltation process of the adjoining river delta.

Sweeping tickler chains and otter boards of the shrimp trawls plough over the sandy and muddy seabed, thus changing the natural pattern and firmness of the bottom habitat. The turbidity of the water is increased. The numerous habitats of the numerous bottom dwelling organisms, such as worms and sea urchins are destroyed.

9. PERCEPTION OF THE PRESENT SITUATION REGARDING SHRIMP EXPLOITATION INCLUDING ENVIRONMENTAL IMPACTS

9.1 By artisanal fishermen

The artisanal fishermen have traditionally set gillnets on the trawl grounds and occasionally these are lost when fouled by the trawl gear. The Fisheries General Regulations of 1973 provide that the lost or damaged gears should be compensated, and that all gears be suitably marked to enhance visibility. Despite these requirements some gears continue to be lost, and thus artisanal fishermen regard shrimp trawling as detrimental to their fishing gear.

Fisher Communities along the coast considerthat shrimp trawling with discarding of large quantitites of fish is wasteful practice. The Communities are now reporting declining artisanal fish catch in fishing grounds where trawlers have operated.

9.2 By the Fisheries Authorities

The Fisheries Authorities observe that trawling requires close monitoring to ensure that there is no environmental degradation which could result in the alteration of marine ecology and hence in a reduction of marine resources with the possibility of generating social economic losses.

In addition, observing that the catch from the trawlers is close to the estimated MSY, the Authorities decided to limit the number of vessels to avoid over-investment as well as stock depletion.

10. THE SOCIAL IMPLICATIONS OF ADJUSTING FISHING TO MORE ENVIRONMENTALLY FRIENDLY PRACTICES

The shrimp trawls have increased the supply of fish for local consumption especially in Dar Es-Salaam and other regions close to it. Several young Tanzanians are working in the fishing vessels.
The Government's Policy in respect to the management of the fisheries gives priority to y2859etaining development, particularly with regard to the rural community.

The real strength of the prawn fishing industry on the coast of Tanzania lies in the multitude of small scale fishing communities scattered along the coast of the Indian Ocean. Artisanal fishermen are also engaged in agricultural activities. As a result they supply part of the country's fish production, as well as rice, coconut, cassava, etc. In terms of future developments, the National Fisheries Authorities consider that the artisanal sector, as a whole, has the potential to provide much more fish and prawn if small scale fishermen are provided with motorized boats or proper fishing craft and gear.

11. NATIONAL IDENTIFICATION OF PRIORITY ISSUES REQUIRING ACTIONS TO MEET ACCEPTABLE STANDARDS OF ENVIRONMENTALLY FRIENDLY SHRIMP EXPLOITATION

The National Fisheries Sector Policy and Strategy Statement addresses the problems of conservation, management and development of the fisheries resources.

There is still unsufficient consciousness of the potential value of the fisheries resources and, therefore, unsufficient attention to resources conservation and management of the fisheries.

However, the relevant National Statement focuses on the promotion of sustainable exploitation, utilization and marketing of fisheries resources to provide food, income, employment and foreign exchange earnings and effective protection of the aquatic environment to sustain development.

The Fisheries Policy encompasses the need for a change in attitude towards fisheries resources use practices as well as the necessity to manage, conserve and develop them for common prosperity.

To meet acceptable standards of environmentally friendly shrimp exploitation, the Fisheries Sector is facing a number of problems which require actions: including, among other:

• Insufficient information on the resource available
  
• Lack of capacity to carry out research
  
• Poor handling and inadequate processing methods and technologies
  
• Poor transport and distribution network leading to high levels of post-harvest losses
  
• Inadequate national capacities and infrastructure for training
  
• Environmental degradation and inability to integrate environmental protection with development
  
• Insufficient empowerment of the local communities
  
• Lack of discussion on issues and action from fisheries communities
  
• Unfavorable credit condition from money lending institutions
  

• Lack of recognition of the value, on long-term, of the fisheries resources and its potential contribution to the economy
  
• Inadequate financial and technical resources
  
• Low level of technology among the artisanal fishing communities
  
• Inadequate support services, including for research and extension
  
• Lack of proper equipment for fishing, fish handling and transport facilities
  
• Lack of appreciation of the gender perspectives in the fisheries activities
  
• Unsufficient reliance of Donors for funding projects in the country
  
• Inability to fully exploit the National Exclusive Economic Zone (EEZ)

• Integration of conservation and sustainable utilization of the fisheries into the socio-economic programmes for the Sector
  
• Encouragement and support of all initiatives leading to protection and sustainable use of the fish stocks and aquatic resources
  
• Protection of the productivity and of the biological diversity of coastal and aquatic ecosystems through prevention of habitat destruction, pollution and over exploitation.
  

• Control/ban destructive fishing and processing methods
  
• Monitor and review environmental protection measures applied in the fisheries sector
  
• Promote protection of the fragile ecosystem, ecosystem processes and conservation of bio diversity.
  
• Protect endangered and threatened aquatic species throughout their life
  
• Protect vulnerable species, habitats and areas of special ecological significance through accordance of special status to such areas e.g. marine parks, marine reserves and closed breading areas
  
• Adopt relevant regional and international protocols and treaties for protection and conservation of the fisheries resources and aquatic environment.

12. PROPOSAL FOR A PLAN OF ACTION FOR DEVELOPMENT OF ENVIRONMENTALLY FRIENDLY TECHNIQUES AND PRACTICES FOR SHRIMP EXPLOITATION. A STUDY TO EVALUATE THE IMPACT OF THE NATIONAL FISHERIES POLICY ON THE MANAGEMENT OF THE COASTAL PRAWN RESOURCES

The knowledge, perception and attitudes of the stakeholders in the fishing industry, towards the national fisheries policy are not known. It is imperative that the people's knowledge be tapped as a basis for decision making.

Long-term objective of the study

To formulate strategies which will enable the exploitation of the marine resources in an environmentally friendly manner to the benefit of the coastal communities and the country, in general.

Short term Objectives

1. Assess the impact of the current fisheries policy on the management and development of prawn fisheries by artisanal and industrial fishermen.

2. Evaluate the attitude of stakeholders (fishermen, fish traders, processors, local and central government officials) regarding prawn resources and their exploitation.

3. Determine the impact of artisanal and industrial fisheries activities on the environment in and near fishing grounds.

4. Improve the technical and economic efficiency of the fishing, processing and marketing sectors of the prawn fishery in order to raise incomes of coastal community households.

5. Increase opportunities of employment for coastal communities in the fishing, processing and marketing sectors of the prawn fishery.

6. Increase, in particular, opportunities of employment for coastal women and youth.

7. Facilitate the access of small scale (artisanal) fishing, processing and marketing sectors to necessary supply through the provision of credit.

8. Suggest improvement of extension services to small scale (artisanal) fishing, processing and marketing sectors through the provision of technical assistance.

9. Determine and recommend policy strategies for improving the social and economic welfare of artisanal fishermen and their communities.

The programme and relevant Plan of Action concerning a reduction of the impact of the shrimp fisheries will benefit to a wide range of stakeholders including Artisanal fisheries, Fisheries Authorities, fishing communities, in particular, women and rural unemployed youth, boats owners, other local and foreign investors on the prawn fishing industry and other related activities like boat building, making of ice containers and ice blocks.

Other local on the coast of Tanzania. Owners of the Commercial prawn trawlers.

It is expected that the y2859e components of the Plan of Action will include, in particular:

- To publicize and make the Fisheries Policy known to all stakeholders in the prawn fishing industry.
- Training in the construction of By-catch Reduction Devices in the National Fisheries Training Institutes.
- Tests and demonstration of the use of By-Catch Reduction Devices to Prawn Trawler Operators.