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THE PHILIPPINES

SHRIMP TRAWL FISHERIES IN THE PHILIPPINES

(National Report presented to the GEF/UNEP/FAO Workshop in the Reduction of the Impact of the Shrimp Fisheries, Denpasar, Indonesia; 6-8 March 2000)

by Jonathan O. Dickson, National Coordinator (Chief, Fishing Technology Division
Bureau of Fisheries and Aquatic Resources; 860 Arcadia Bldg., Quezon Avenue; Quezon City, Philippines; Tel # 632- 372-5051 Fax # 632-372-5056; email: bfarnmfd@info.com.ph)

Abstract

In 1997, the catch of shrimp was 7 156 t (90% Acetes) from the industrial fleet (445 vessels in 1997) and 25 334 t from the artisanal sector (over 50% of the catch are white shrimp (P.merguiensis) and endeavour prawns (Metapenaeus ensis), 34% are Acetes; push net, "baby trawl", fyke net, fish coral, gillnet beach seine and filter net are the most common gear).

Shrimp constitute only 10% of the total catch in trawl fisheries. Discard rates are unknown but likely to be relatively small as there is a market for most of the captured fish.

Shrimp y2859ely go to the local markets. Small-sized fish are utilized as fish feed for aquaculture.

All vessels need a licence to fish. Mesh sizes less than 25 mm are not allowed in shrimp fishing. Partial/total closure of some trawl areas are now implemented due to declining catch rates.

In order to ensure sustainability of the shrimp fisheries the challenge is to develop solutions that retain bigger fish allowing juveniles and turtles to escape while not causing an immediate economic loss for the fishers.

Resumen

En 1997, las capturas de camarón reportadas por la flota industrial (445 embarcaciones en 1997) alcanzaron las 7.156 toneladas métricas (90% Acetes), mientras el sector artesanal reportó 25.334 toneladas métricas ese mismo año. Más del 50% de las capturas artesanales estuvieron constituidas por camarón blanco (P. merguiensis) y langostino "endeavour" (Metapenaeus ensis), el 34% por Acetes. Las artes de pesca utilizadas más frecuentemente son: red de empuje ("push net"), red de arrastre menor ("baby trawl"), red falsa ("fyke net"), corral de peces ("fish coral"), red de enmalle ("gillnet"), red de orilla ("beach seine") y red filtrante ("filter net").

El camarón constituye sólo 10% del total capturado en la pesca de arrastre. Se desconocen las tasas de descartes, pero al parecer son relativamente bajas dado que existe un mercado para la mayor parte del pescado capturado.
El camarón se destina principalmente al mercado local. El pescado de talla pequeña se emplea en la elaboración de alimento para peces de acuicultura.

Todas las embarcaciones de pesca requieren una licencia para llevar a cabo la actividad. No está permitido el uso de abertura de malla inferior a los 25 mm en la pesca de camarón. Actualmente se implementa el cierre parcial o total de algunas áreas de arrastre debido a la caída en las tasas de captura.

Con el fin de asegurar el rendimiento sostenible de la pesquería camaronera, el reto es desarrollar soluciones que permitan retener los peces más grandes, permitiendo al mismo tiempo el escape de juveniles y tortugas sin ocasionar pérdidas económicas inmediatas a los pescadores.

1. INTRODUCTION

A. Location

The Philippines, an archipelagic country composed of over 7,100 islands, is endowed with a vast expanse of marine and inland water resources. It is situated in the Western Pacific and bounded on the east by the Pacific Ocean, on the west by the Luzon Sea, in the South by the Celebes Sea and Bornean Waters just a few degrees north of the equator, and in the north by the Taiwanese waters. Its territorial waters as defined in the 1898 Treaty of Paris had an area of about 1,666,000 km2 but with the promulgation of the Exclusive Economic Zone, the territorial marine area is increased to 2,200,000 km2. It has a land area of 300,000 km2 and about 17,460 km of coastline. The coastal and oceanic waters occupy 12% and 88% of the total marine areas respectively (Figure 2).

B. Fisheries Industry

The fisheries industry is sub-categorized into municipal, commercial and aquaculture. The municipal refers to fishing within the municipal waters (0-15 km from shore) using fishing vessels of three (3) gross tonnes or less, or fishing not requiring the use of fishing vessels. The commercial sector refers to taking of fishery species by passive or active gear for trade, business or profit beyond subsistence or sports fishing using vessels with more than three (3) gross tonnes. Aquaculture sector involves fishery operations engaged in all forms of raising and culturing fish and other fishery species in fresh, brackish and marine areas.

In 1997 the contribution of the fisheries industry to the country's Gross Domestic Product (GDP) and were 2.8% at current prices and 3.8% at constant prices. Total fish production in 1997 reached 2,766,663 MT, valued at PhP80.7 B, of which 33.4% came from municipal fisheries (924,466 MT), 32.0% from commercial fisheries (884,651 MT) and 34.6% from aquaculture. From 1988-1997, the average annual growth rate was 2.2%. Positive growth of 5.3% was posted by aquaculture. Inspite of the slight decrease by 0.09% of the output of the fishing industry in 1997, aquaculture still posted a 6.7% increase in production.

The municipal resources consist mostly in fishes. Invertebrates like blue crabs and squids also contribute significantly to the production. The five (5) major fish produced based on 1996 statistics were fimbriated sardines, squid, anchovies, frigate tuna and indian sardines. The fishing gears being used are generally simple, low cost, and easily operated by fishermen using motorized and nonmotorized fishing boats ("bancas"). The most common fishing gears are gillnet, hook and line, beach seine, fish corral, ringnet, trawl, spear, longline and danish seine. From 1992 -1995, gillnet was the most productive. The major fishing grounds are Visayan Sea, Bohol Sea, East Sulu Sea, Moro Gulf and Guimarras Strait.

As far as the commercial sector is concerned, in 1996, 27% of its production came from the National Capital Region with as major species caught: roundscad, sardines and tuna. The y2859e fishing gears are purse seine, ringnet, trawl, danish seine and bagnet while the productive fishing grounds are West Palawan waters, Tayabas Bay, Lamon Bay, Manila Bay, Sibuyan Sea and Cuyo Pass.

2. THE TRAWL INDUSTRY

Trawl is recognized as one of the most-efficient fishing gear for harvesting shrimps. This method has become popular in the country before and during Japanese colonization in the 1940's. Umali (1950) reported that Japanese fishermen were already operating beam trawls at that period. Just after, pair trawling (two-boat-trawling) was also introduced but in limited quantities. After the liberation period, the Americans popularized otter trawling using one-boat. This was made possible through explerimental trawling carried out by Warfel and Manacop (1950) in some parts of the country. With the remarkable efficiency of the gear, otter trawl was widely accepted and adopted by the industry in the 1960's. In 1967, there were 600 units in operation in Philippine waters (Encina, 1976). After three decades, licensed commercial trawlers in 1997 reached around 445 units (62% classified as small-commercial (i.e. 3 to 20 GT); 37% medium-commercial (20 to 150 GT); and 1% large-commercial trawlers (150 GT and above) (BFAR Profile, 1997). Mini-trawl or "baby-trawl" operating in coastal and inshore parts of the country is unaccountable, but, estimated to be common.

Municipal and commercial trawling can be distinguished within the trawl industry sector of the Philippine fisheries: The municipal trawling sector utilizes wooden dugout fishing crafts or "banca" measuring 5 to 12 m over-all length. Such crafts are propelled by 10-90 HP gasoline or diesel engines. The commercial trawl sector utilizes bigger-sized boat with greater engine power. As already mentioned above, the later can be further classified as: small-commercial (3 to 20 GT); medium-commercial (20 to 150 GT), and, large-commercial type (150 and beyond). The boat more than 15 m in length, with engines ranging 150 to 500 HP areoften equipped with mechanized pulleys for hauling the net.

Trawl has been contributing to around 13% of the Total Annual Production from 1992-1995 (Table 1). At this time, in the municipal waters, trawl ranked 6th among the most productive municipal fishing gear after gillnet, hook and line, beach seine, fish corral and ring net according to Bureau of Agricultural Statistics. In the commercial fisheries sector, trawl is the fifth, after purse seine, ringnet, danish seine and bagnet in terms of over-all production.

The most common trawling method consists in single trawling, the net being horizontally opened by two wooden otter boards. The vertical openings may be slightly adjusted depending on the targeted species. High-vertical opening trawls or the semi-pelagic fish trawls being towed at high speed (i.e., averaging 4 knots or greater) can capture fast-swimming fish

TABLE 1. Contribution of the Trawl Fisheries Sector to the
Total Municipal and Commercial Production from 1992-1995

Year

Trawl
(Municipal)

Total Municipal
Production
Trawl
Commercial
Total Commercial
Production
1992
36,705
854,687
90,547
804,866
1993
41,923
803,194
86,965
945,431
1994
27,277
786,847
88,423
885,446
1995
23,517
785,369
66,089
926,887
Contribution by sector (%)
4.01
 
9.66
 

On the other hand, low-vertical opening trawls or shrimp trawls, are normally scrapping heavily the bottom to capture shrimp and fish dwelling on it; they have greater drag and are towed at slower speed. In general, the codend is made of single layer netting with protective chaffer using mesh sizes of 3-4 cm although, smaller mesh sizes are frequently used in coastal waters (1-3 cm).

3. SHRIMP FISHERY

3.1 Shrimp Resources

The exploitable shrimp resource in the country consists in species of the Penaied family. These are the Penaeus merguiensis (white shrimp), P. semisulcatus (tiger shrimp) and Metapenaeus ensis (endeavor shrimp). Other important shrimp species include the Acetes as raw material for shrimp paste and brown rough shrimp (Trachypenaeus fulvus) usually processed in dried form. Many other species are found throughout the country in marine waters and, also, in brackish and fresh waters but in less quantity (Del Mundo, 1990; Caces, 1973; Motoh, 1980).

The shrimps for local consumption are products from the municipal and the commercial fishery sector while the shrimps which are exported come entirely from aquaculture. The percentage distribution of shrimp and production performances by sector from 1992 to 1997 is provided in Figure 1 and Table 2.

PHILIPPINE MARINE JURISDICTIONAL BOUNDARIES

Figure 2. Map of the Philippines showing the limits of archipelagic, Territorial Waters treaty limits, Exclusive Economic Zone (200 N.M. E.E.Z.) and Figure 2. Kalayaan Claim. It also shows the location of Manila Bay, San Miguel Bay, Ragay Gulf and Sorsogon Bay

TABLE 2. Shrimp Production by Sector (1992-1997) in MT

Sector
1992
1993
1994
1995
1996
1997
Aquaculture
78,386
95,816
92,647
89,196
78,067
41,454
Municipal fisheries
43,880
27,810
26,497
32,068
31,100
25,334
Commercial fisheries
4,997
9,860
9,153
9,027
8,741
7,156
Total
127,273
133,486
128,297
130,291
117,908
73,994

Tables 3 and 4 present shrimp production and relative abundance by species in marine capture fisheries.

TABLE 3. Municipal Shrimp Production by species (1992-1996) in MT

Species
1992
1993
1994
1995
1996
%
I. Inland
 
 
 
 
 
 
Freshwater shrimp
8,474
1,249
1,439
3,606
3,971
75
Freshwater lobster
6
2,025
281
422
711
13.8
White shrimp
 
 
1,216
431
360
4.4
Endeavor prawn
 
 
192
237
225
4.4
Acetes
 
77
11
39
24
0.7

Total Inland

8,480
3,351
3,139
4,735
5,291
(16)
II. Marine
 
 
 
 
 
 
White shrimp
13,085
12,756
10,144
9,856
9,108
40.3
Acetes
16,209
6,241
6,432
8,966
8,657
34.0
Endeavor prawn
4,268
3,110
4,794
5,672
5,179
16.9
Brown rough shrimp
910
946
1,059
1,680
1,739
4.6
Tiger prawn
928
1,406
929
1,159
1,126
4.1
Total Marine
35,400
24,459
23,358
27,333
25,809
(84)
Total Municipal
43,880
27,810
26,497
32,068
31,100
(100)


TABLE 4. Commercial Shrimp Production by species (1992 to 1996) in MT

Species
1992
1993
1994
1995
1996
%
Acetes
4,003
8,992
8,292
8,232
8,144
90.0
Endeavor prawn
427
387
341
382
252
4.3
White shrimp
294
435
486
288
220
4.1
Brown rough shrimp
229
35
26
119
117
1.3
Tiger prawn
44
11
8
6
8
0.2
Total Commercial
4,997
9,860
9,153
9,027
8,741
100.0

3.2 Production Methods

In addition to trawling, 11 fishing methods are known as exploiting, directly and indirectly, shrimp resources in municipal waters and 5 methods in commercial sector. For small-scale and large-scale shrimp fisheries in both municipal and commercial waters, the majority of the captures come from pushnets and trawls (Table 5 and 6).

TABLE 5. Municipal Shrimp Production (in MT) by Fishing Gear, 1995

Fishing Gear
White Shrimp
Acetes
Endeavor Prawn
Brown rough shrimp
Tiger Prawn
Total
%
1. Pushnet
2,144
3,930
807
19
42
6,942
25.76
2. Baby trawl
1,110
672
1,443
1,025
621
4,871
18.08
3. Fyke net
7
3,065
 
 
 
3,072
11.40
4. Gill net
1,963
55
437
264
88
2,807
10.42
5. Fish corral
1,496
19
737
299
89
2,640
9.80
6. Beach seine
1,435
941
50
1
89
2,516
9.34
7. Filter net

475

1 1,658 58 176 2,368 8.79
8. Fish pot 296   96 2 2 396 1.47
9. Cast net 192   6   9 207 0.77
10. Danish seine 76   47   5 128 0.48
11. Ring net 113         113 0.42
12. Lift net 53 3   1 2 59 0.22
13. Others 496 280 391 11 36 1,214 4.51
Total 9,856 8,966 5,672 1,680 1,159 27,333 100.00

TABLE 6. Commercial Shrimp Production (in MT) by Fishing Gear, 1995

Fishing Gear Acetes Endeavor Prawn White Shrimp Brown rough shrimp Tiger Prawn Total %
1. Pushnet 6,745 41 59     6,845 75.83
2. Trawl 942 232 156 50 6 1,386 15.35
3. Beach seine 529 1 2     532 5.89
4. Purse seine   106 33 68   207 2.29
5. Gillnet 14 1 33     48 0.53
6. Others 2 1 5 1   9 0.10
Total 8,232 382 288 119 6 9,027 100.00


3.3 Fishing Grounds (Figure 2)

A. Description

A.1 Sorsogon Bay

Sorsogon Bay is a shallow inlet with an area of 256 km2 located at the southern tip of Luzon Island. It is bounded by longitude 123°50'E and 124°10'E and latitude 12°59'N. The bottom of the Bay consists of muddy flat bottom ranging from 0.5 to 9 m in depth with an average 4.4 m. The deepest portions are from 10 to 29 m deep with few coral reef fringes. Wet climate prevails throughout the year and highly pronounced from months of November to January.

A.2 San Miguel Bay

San Miguel Bay is located in the southeastern part of Luzon Island covering an area of 1,152 km2. The bay features a very shallow area at the inner and central portion (3 to 10 m) of the coasts that gradually deepens at the outer canal leading to the Pacific Ocean (31 m deep). Mudflats comprise 95% of the substrate cover with few rocky and coral fringes near the mouth of the Bay. The bay is an estuary where freshwater inflow from major river tributaries significantly dilutes seawater. These waters with mixed origin have higher temperatures, thus possess high-biological production.

The climate in San Miguel Bay is characterized by no dry season and heavy rainfall from November to January. The northeast monsoon from November to March brings extremely strong winds while the south monsoon (June to October) has little or no effect.

A.3 Ragay Gulf

Ragay Gulf is located in the southwestern part of the Luzon Island in the Philippines. It is bounded on the west and north by the province of Quezon and on the northeastern and east by the province of Camarines Sur; it is demarcated at the south by an imaginary line that crosses eastward for 122°40'75'' E, 13°19'4'' N to 123°13'72'' E, 13°19'4'' N. The Gulf covers approximately 3,912 km2 and characterized by narrow shelf and deep waters up to 600 m depth. Shelf areas along the Gulf are predominantly smooth and muddy. There are also coral reef areas along the coast, in particular along the southern portion of the Bondoc Peninsula.


A.4 Manila Bay

Manila Bay is a semi-enclosed body of water bounded by the shoreline of Cavite, Metro Manila, Bulacan, Pampanga and Bataan. It covers a total area of 1,782 km2 with a length of 60 km, a varying width from 22 km at its mouth to 60 km at its widest portions, and is located roughly between latitudes 14015' and 140 50' North and longitudes 1200 30' and 1210 00' East. The bay is relatively shallow with an average depth of almost 19 m. 80% of the bay area is less than 30 m deep.

Manila Bay's climate is characterized by two pronounced seasons: dry from November to May and wet from June to September. The northeast monsoon dominates from October to February while, from March to May, the Southeast Trade Winds occur. The southwest monsoon prevails from June to September (FSP-REA Manila Bay).

B. Production

B.1 Sorsogon Bay

Sorsogon Bay is essentially a municipal fishing area where for the period 1992-1995, production was estimated to have an annual average of 5,300 MT (BAS, 1995) of which an average of about 12% was supplied by baby trawl (Table 7).

For 1996, the landing was estimated to be around 5,818 MT, almost 5% of which had been caught by "mini-trawls" (Cinco et. al.). The y2859e other gears in terms of production are gillnets, "modified Danish seine", fish corral and crab gillnet.

TABLE 7. Contribution of Baby trawl to the Total Marine Municipal Catch from 1992-1995 in Sorsogon Bay

Year Baby Trawl
(MT)
Marine Municipal Landing (MT) Percent (%) contribution of Baby Trawl
1992 444 3,522 12.6
1993 425 3,208 13.2
1994 420 6,848 6.1
1995 1,333 7,625 17.5
Total 2,622 21,203 12.4
Average 655.5 5,300.75 12.4

Typical trawlers found in the area were traditionally of small-scale type. In 1972, BFAR reported 24 mini-trawlers in operation. There was a sudden increase in 1993 to about 155 units (PRIMEX, 1993). In 1994, a municipal ordinance banning trawl operations ceased its further expansion, thus, reducing the number of small trawlers one year later to only 36. Despite the ban, few trawling operations still persist at night time.

The trawls commonly used are two-seam, low-opening, trawl made from polyethylene (PE). The headrope and groundrope length are 3.5 m and 4 m, respectively. The mesh size of the codend is normally about 1.7 cm. The wings of the net are connected to two rectangular otter boards, 0.5 m per 0.75 m in size. Typically, 6 m "bancas, with 10-16 HP gasoline engine, äre used to tow the trawl net.

According to a survey from April 1994 to January 1995, the catch per unit effort would be, for a 16 HP mini-trawler, 6.6 kg/hr (with trawling speed being 2 knots). The cardinalfishes, Portunid crabs, slipmouths, flatfishes and gobies were the y2859e species (64% of the total). Penaeid shrimp accounted for 3.5% only.

For the same type of small trawler, in 1999 (May to August; on a total of 100 drag observations or 200 fishing hours), the average catch rate was found being 7.5 kg/hr. The composition of the catch revealed that species which are normally discarded such as crablets, seamantis and sea cucumber are an average
of 44% of the total catch. Low-valued but marketable miscellaneous species, majority of which are gobies (26%), accounted for 33%. Shrimps shared a high-catch rate of 23%. In order of importance in the catch, the shrimp species consisted in: brown rough shrimp, white, endeavor and tiger shrimp (Table 8).

B.2 San Miguel Bay

For the period 1992-1995, the average municipal production was about 11,103 MT in the San Miguel Bay, with baby trawl contributing 9.2%. (Table 9). The y2859e fishing gears are gillnets and trawls and medium and large trawlers, normally operating in the commercial sector are also found in the Bay. Several assessments indicate that the fishery resources in the Bay are heavily exploited or, even, over-fished with catch rates significantly declining (BFAR-FSP, REA SMB).

TABLE 8. Composition of Trawl Catch (May to August, 1999) in Sorsogon Bay

Group Total %
Target catch 346.3 23.0
Brown rough shrimp 169.3 11.3
White shrimp 121.0 8.1
Endeavor shrimp 54.25 3.6
Tiger shrimp 1.75 0.1
Marketable By-catch 490.0 33.0
Goby 384.7 26.0
Blue-swimming crabs 40.9 2.7
Slipmouth 19.7 1.3
Goatfish 13.1 0.9
Whiting 9.85 0.7
Eel 6.25 0.4
Glassfish 4.25 0.3
Whipfin mojarra 2.75 0.2
Spotted flatheads 1.35 0.1
Octopus 5.5 0.4
Squid 1.5 0.1
Discards/Thrown away catch    
Crablets, seamantis & sea cucumber 657.9 44.0
TOTAL 1,494 100.0

TABLE 9. Contribution of Baby trawl to the Total Marine Municipal Catch from 1992-1995 in San Miguel Bay

Year Baby Trawl (MT) Marine Municipal Landing (MT) Percent (%) contribution of Baby Trawl
1992 1,284 11,255 11.4
1993 987 11,070 8.9
1994 906 10,968 8.2
1995 938 11,121 8.4
Average
1,028.75 11,103.5 9.2
    Source: BAS.

B.2.1 Municipal Trawl Fleet

The small-sized trawl fleets can be divided into two groups: baby trawlers (2-3 GT) and mini-trawlers (2 GT or less). The size of the fleet has shown a large expansion from 1982 to now as shown in Table 10, almost multiplied by two. As a whole, the municipal trawling sector contributed an average of 9% of the total marine municipal landings.

A ten (10) month resource survey was conducted from September 1992 to July 1993 (under the Resource and Ecological Assessment San Miguel Bay Programme) with a trawl operated by a 10 m length boat powered by 65 HP inboard engine. The mean catch rate was 32.3 kg per hour, being highest in October 1992, at 73.9 kg/hr, and lowest in April 1993, at 13.4 kg/hr. Slipmouths (Leiognathidae) composed over a third (37.6%) of the catch, and together with croakers (Sciaenidae), anchovies (Engraulidae), hairtails (Trichiuridae) and shrimps (Penaeidae), comprised over two-thirds (67.4%) of the catch during that period. The results of the survey indicated heavy fishing pressure on the resources of San Miguel Bay. Symptoms of all forms of biological over-fishing were reported.

TABLE 10. Trawl fleet characteristics and sizes in San Miguel Bay

Trawl type Sector Length (m) Engine (hp) # Units (Vakily 1982) # Units REA (1992) # Units DA-BFAR (1992) # Units Rapid Assessment (1999)
Medium Commercial 19-25 250-500 30 1 35 -
Small Commercial 18 150-220 17 4 38 20
Baby trawl Municipal 11 60-90 72 50 - 33
Mini trawl Municipal 7 10-16 188 260 - 569

A catch assessment was also carried out for the months of April, June and August 1999. Day and night time fishing operations were concentrated in the inner parts of the Bay. The tow duration was around two hours at day time and four hours at night. The total catch per unit effort was 4 kg/hr. Shrimp was 15% of the total, other invertebrates (dominated by crabs) 40%, mixted big fish, 20% and trash fish (including small-sized invertebrates such as starfish, seamantis and young/small fish, less than 10 cm in length) accounted 25%.

B.2.2 Commercial Trawl Fleet

After a resolution was called for non allowed entry of commercial fishing vessels in San Miguel Bay, large commercial trawlers have shifted to other fishing grounds (e.g., Lamon Bay). Other units are still operating despite regulations on commercial fishing inside the Bay.

B.3 Ragay Gulf

Similar to other bays and near shore marine areas, Ragay Gulf is essentially characterized by municipal fishery activities. Municipal and Commercial production data sourced from the Gulf are shown in Tables 11 and 12. From 1992-1995 data, the total marine municipal landing depreciated together with the declining production from the municipal trawling sector. The average municipal fisheries production was for the period nearly 12,000 MT of which 9% was caught by baby trawl. The commercial fisheries production was less, an average of 8,200 MT, with 4.3% from trawling.

Trawling operations were, in this period, conducted year round in shallow inner sector of the Gulf with depths ranging from 40 to 70 m by two types of fleets: municipal and commercial trawl fleets.

The municipal trawl fleet, around 105 units, typically used low-opening bottom otter trawls. Hauls were made twice a day with towing duration of 6 hours. No historical data was available to compare the catch per unit effort of this small-scale trawl gear.

TABLE 11. Contribution of Baby trawl to the Total Marine Municipal Catch from 1992-1995 in Ragay Gulf

Year

Baby Trawl (MT)

Marine Municipal Landing (MT)

Percent (%) contribution of Baby Trawl

1992

3,444

13,816

24.9

1993

780

16,598

4.7

1994

306

10,479

2.9

1995

270

6,024

4.5

TABLE 12. Contribution of Trawl Catch to the Total Commercial Production from 1992-1995 in Ragay Gulf

Year

Commercial Trawl (MT)

Commercial Landing (MT)

Percent (%) contribution of Trawl

1992

417

4,118

10.1

1993

271

8,161

3.3

1994

383

13,976

2.7

1995

-

6,786

-

The performances of a typical municipal shrimp trawler, 10 m long with 90 HP engine were assessed from February to August 1999. The recorded catch per unit effort was 3.2 kg per hour of tow (Table 13). The y2859e shrimp species caught were the white shrimp (Penaeus merguiensis) and tiger shrimp (P. semisulcatus) which accounted 20% of the total. By-catches were dominantly composed of threadfin breams (Nemipterus spp.), goatfishes and barracuda. Low valued small fishes were used for making a fish meal while in undersized invertebrates and non-consumable fishes with little or no commercial value were discarded (Table 14).

The commercial trawl fleets, on the other hand, about 17 units, used high opening bottom otter trawl, also referred to as "norway trawl" towed at relatively high speed, thus, making the catch of pelagic species possible. The average catch per unit effort was 127 kg per hour of tow. Day time fishing was commonly practiced with tow duration of 2 hours per haul with peak operations in April and May. The mesh size in the codend is usually 2 cm. The dominant species caught by "norway trawl" were Sardinella longiceps and S. fimbriata accounting 35 and 15% of the catch, respectively. It is worth mentioning that the commercial trawl fisheries experienced problems regarding the Territorial Use Rights Fisheries (TURF).

TABLE 13. Monthly catch per unit effort of boarded shrimp trawl in Ragay Gulf

Month

(1999)

CPUE (kg/hr)

Fishing hrs.

    February

3.

36

    March

3.4

36

    April

-

-

    May

3.9

36

    June

2.9

36

    July

3.5

72

    August

2.7

72

    Average

3.2

 

B.4 Manila Bay

Contibution of baby trawl and commercial trawl sectors to the Total Fish Production are shown in Tables 15 and 16. The performances of the commercial trawlers make that their contribution to the total production is more than the municipal trwaling sector. From 1992 to 1995, the trend of capture is not so clear for the commercial trawling sector but the municipal production showed a clear declining trend.

TABLE 14. Catch categorization by Total Relative Abundance (%)

Month (1999)

Shrimp

By-catch

Fish meal

Discard

%

February

28.

46.

19.

7.

100

March

23.

44.

20.

13.

100

May

14.

55.

15.

16.

100

June

20.

54.

9.

17.

100

July

16.

61.

8.

15.

100

August

17.

55.

10.

18.

100

Average

20.

52.5

13.5

14.

100

TABLE 15. Contribution of Baby trawl to the Total Marine Municipal Catch from 1992-1995 in Manila Bay

Year

Baby Trawl (MT)

Marine Municipal Landing (MT)

Percent (%) contribution of Baby Trawl

1992

2222

17598

12.6

1993

1721

13245

13.0

1994

1341

12750

10.5

1995

1525

11652

13.1

Average

1702.25

13811.25

12.3

TABLE 16. Contribution of Trawl Catch to the Total Commercial Production from 1992-1995 in Manila Bay

Year

Commercial Trawl (MT)

Commercial Landing (MT)

Percent (%) contribution of Trawl

1992

5,036

15,587

32.3

1993

10,105

20,740

48.7

1994

10,196

26,222

38.8

1995

9,859

25,046

39.3

Average

8,799

17,519

50.2

B.4.1 Municipal Trawl sector

There Resource and Ecological Assessment Programme in Manila Bay found around 346 baby trawling units in 1992/1993. The standing biomass was assessed through a trawl survey using a 13.5 m trawler. The catch per unit effort had found an average of 10 kg per hour. The mean CPUE was highest in September to October, 13.8 kg/hr and lowest in March to April, 5.2 kg/hr. Historical data show (Table 17) large fluctuation of the CPUE from 1947, with a clear decreasing trend from 1970: 61.8 kg/hr in 1970 to 14.0 kg/hr in 1986.

TABLE 17. Historical Information from different Trawl Surveys in Manila Bay

Year

CPUE

(kg/hr)

Composition

Fish Invertebrates

1947

44.0

   

1948

45.8

   

1957

16.2

   

1958

13.3

81

19

1959

12.2

   

1960

15.7

96

4

1961

13.6

   

1962

16.3

91

8

1966

14.0

   

1970

61.8

   

1971

37.4

   

1980

 

79

21

1983

27.9

80

20

1986

14.0

36

64

1993

10.0

75

25

*1996

10.4

41

59

Another survey was conducted from August to December 1996 with a baby trawling unit (11 m in length and 80 HP engine). The results indicated a similar catching efficiency of 10.4 kg/hr (Table 18) with invertebrates being dominant in the catches (Table 19).

B.4.2 Commercial Trawl Sector

In 1997 the number of commercial trawling units licensed for the Manila Bay was as follows: 159 "small-commercial" units and 67 "medium commercial" one. The medium-commercial vessels continued their operation beyond the Manila Bay, along vicinities of Zambales, Subic Bay and Palawan waters while a few small-commercial vessels normally operating in the middle-portion of the Bay, encroach on municipal waters.

TABLE 18. Monthly catch per unit effort of a baby trawling unit in 1996 in Manila Bay

Month

CPUE (kg/hr)

Fishing hours

August

7.4

10

September

8.8

8

October

19.6

9

November

8.0

10

December

8.3

10

Average

10.4

9.4


TABLE 19. Catch composition of a baby trawling unit in 1996 in the Manila Bay in Relative Abundance (%)

 

INVERTEBRATES

 

%

Month

Shrimp

Edible Crusta-

Ceans

Inedible

Crusta-

ceans

Cepha-lopods

Big Fish

Small-Fish

Trash fish

August

10.

28.

27.

2.

8.

6.

18.

100

September

5.

36.

23.

2.

11.

3.

20.

100

October

11

10.

16.

5.

8.

2.

48.

100

November

10.

19.

25.

6.

10.

20.

10.

100

December

16.

6.

34.

5.

6.

19.

14.

100

Average

10.

20.

25.

4.

9.

10.

22.

100


C. Socio-economic Role of Trawl Fishery

C.1 Competition

The trawl fisheries are acknowledged to have contributed significantly to the country's increased fish production since its introduction in the 1940s. Even with the present assertion that trawl has contributed to resource depletion and environmental degradation, trawling is still a major fishing method.

Considering its contribution to production, trawl fishing is very important: Around 9% of the total production in some commercail areas such as Ragay and San Miguel, 12% in Sorsogon and Manila Bays; even higher in the municipal waters. In addition, trawling is employing a lot of fishermen.

In general, the fishing technology to be used is required allowing the catch of demersal species on e flat and muddy bottom. While trawl fishing is the most common fishing method, in general, other fishing gears are also catching shrimp: Some are specifically designed for shrimp such as shrimp gillnet, other are catching shrimp in addition to other species e.g. pushnet, seine net, lift net and stationary trap such as fish corral, fyke net, filter net, etc. The rate of capture and the catch composition depend on the type of gear and the mode of operation, but, in general, the shrimp is a minor part of the catch. Penaeid shrimp species have normally sparse distribution and often caught only at night. The large shrimp are, in general, exploited, in deeper waters, offshore while other shrimp resources, small species such as Acetes are tapped in more dense concentration and seasonally (during the southwest monsoon) in the inner portions of the bays. It is worth mentioning that, in general, young shrimps are more common in shallow coastal areas where stationary gears are installed.

In the bay two categories of fishing operators are met: - municipal or small-scale fishermen and - commercial or industrial fishermen. The use of bigger boats and better fishing make that commercial operators are very effective, placing the municipal fishermen in a difficult position to compete when on the same fishing grounds. Some small-scale fishermen groups facing great difficulties resort to illegal forms of fishing such as dynamite and cyanide, to ultimately get some income.

The stiff competition among users and harmful fishing practices resulted in an overall decrease in fish catch a decrease in the catch of adult fishes and an increase catch of juveniles; high mortality of fishes; increasing portion of invertebrates; destruction of coral reef and bottom communities; decrease water transparency; etc. If this situation continues, the marine productivity in a number of bays will further be lowered.

The depleted state of marine resources and the increasing population in the coastal communities of San Miguel Bay resulted in increased competition and intensified conflict between and among user groups.
The encroachment of trawlers into prohibited zones, despite existing fisheries laws and regulations, resulted in uneven catch and income for small-scale and subsistance fisheries in the bay.

Some small fishers were left with no choice but to use illegal and destructive fishing methods to meet the needs of their families.

C.2 Several aspects

The lack of employment opportunities and alternatives to supplement low household incomes greatly contributed to increased fishing effort in the bay.

Twelve villages bordering the San Miguel Bay were surveyed. A sample of of 536 fishing households was selected from 1993 census out of 1, 341 householdswere selected.

The data from the sample survey indicate a wide variation in the nature of fishing activities in the 12 villages. In the smaller villages, owner-operators (full and part owners) outnumber fishermen.

The nature of fishing activities also tends to vary with the age of the respondent. Owner-operators (notably full-owners) tend to be concentrated in the upper age brackets and non-owners operators (fishermen) in the lower age brackets. This pattern can be explained by the fact that many young fishers have not yet accumulated sufficient capital to own a boat and gear.
A total of 94% of the respondents were married and had wives living with them in the household. The respondents had an average of 4.2 children, of whom an average of 3.3 were living in the household. Among the people documented in the survey, almost half (46%) were 20 years old or less. Seventy nine percent had gone through sixth grade or above. Nine percent had gone through high school or beyond. Only one of the respondents had no education at all. Females tend to have slightly more education than males. Fifty-two percent of females and 50% of males had a sixth grade education or above.

In 1980-1981, there were over 3,500 units of fishing gear being used in San Miguel Bay. Forty two percent are gillnetters, about 18% are scissor net, 12% hook and line, and the rey2859eing are mini trawl, stationary liftnet, fishpot, longline, fish corral, crab liftnet, filternets, spearguns, beachseine, fish weir, round hand seine, cast net, etc. Gillnetters and trawlers operate year round catching the bulk of the Bay's total catch. The majority of gillnetters and trawlers are based in the three municipalities of Cabusas, Calabanga and Tinambac. Although the whole year is considered productive, the southeast monsoon (habagat) favors the operation of gillnetters while the northeast monsoon (amihan) favors the operation of mini trawlers. From October to June, Acetes (sergestid shrimp) are the predominant species landed in Castillo. From June to October, mini trawlers catches decline in volume as many of the operators modify their net increasing the mesg size for catching bigger shrimps.

Before mini-trawlers appeared in San Miguel Bay, fishermen stated that daily catches of pushnets could reach 50 kg or more. But catches declined after the introduction of mini-trawlers. The pushnets are normally used for three months June to August only and catch consists mostly of Acetes (sergestid shrimp) with occasional larger shrimps. The fishermen are part time seasonal fishermen supplementing their household income.

Mini trawlers are the smallest trawlers in San Miguel Bay: an average of 10.5 m long, 0.9 m wide and 16HP gasoline engines. Unlike the gillnetters, the mini trawlers have no outriggers. Trawling speed is very slow, estimated to be 1 knot and manned usually by a crew of two. It uses two types of net which have the same body but differ in mesh size and material in the codend: either with fine meshed screen or bigger one (17 knots nylon). Specific nets for Acetes (sergestid shrimp) are used from September to June while the shrimp trawls are preferred from July to August. A typical fishing trip for a mini trawler lasts only one day.

In San Miguel Bay, according to a survey in November 1999, shrimp resources are exploited by baby trawl (koto-koto) and gillnets. The baby trawlers and gillnetters are wooden "banca"with an outrigger and with or without engine. 10 to 16 HP engines are usually common. The average length of a traditional "banca" is 7 m, width and depth, 0.6 and 0.7 m respectively.

Trawling banca measuring 9 m and above overall length have engine from 60 to 80 HP. The trawlers operate throughout the year with average maximum catch of 40 kg per day during peak season from September to March when the water is turbid due to the northeast monsoon. During lean season (April to October), the average catch per day is 20 kg. The catch composition consists, as a rough, general estimate, in shrimp amounting 15%, crabs 40%, assorted fish 20%, and trash fish 25%. The bancas using shrimp gillnets, smaller and with less powerful engine, operate from November to march and from May to September. The duration of operations vary from 4-12 hours daily and the average catch ranges from 5-10 kg per day. Shrimps are about 10% of the total catch, crabs 20%, assorted fish 65%, and trash fish 5%.

Both types of operation employ one or two fishermen per banca. As for the revenues, the sharing schemes are of two types: - Either the operating expenses are deducted from the total sales and the net income will be divided into two equal parts for the two fishermen; - or, the net income is divided into three parts, one share goes to the banca, one to the owner, and one to the fishermen. Shrimp catches upon landing are handled by the brokers who bring the catch to Manila for local distribution to the wet/fresh fish market, restaurants and hotels.

4. REGULATIONS AND MANAGEMENT MEASURES

In the 1980's, the decrease of the profits caused by the lower level of productivity, the increase of the costs of operations and more competition between multiple fishery, prompted the establishment of some management restrictions for trawl fisheries.
Regarding commercial trawl fisheries, the regulation consists in - closed seasons for areas which are known as being overfished (Fisheries Administrative Order (FAO) Numbers 130; 131; 132; 134; 136; 137 and 142); and - designation of fishing zones (i.e., prohibition of fishing within 7 km distance from shore (Letter of Instruction (LOI) 1296; Presidential Decree (PD 281) and within 7 fathoms deep (Republic Act 3048); in 1983, Letter of Instruction No. 1328 was promulgated to close commercial trawl fishing within 7 km from the shoreline and within 7 fathoms deep on a nationwide basis).

The most recent legal decision was Republic Act # 8550 (1998), also known as The Philippine Fisheries Code, closing the bays, gulfs, and other inland waters for vessels utilizing active fishing gears such as trawl.

FAO 156 provides guidelines and procedures in the effective implementation of the above mentioned Letter of Instruction No. 1328 prohibiting commercial trawl fishing within 7 km from the shoreline and within 7 fathoms deep in the whole country. There is an urgent need to improve the standard of living in the rural fishing communities of the country. The prohibition of commercial trawling, but also, commercail purse seining in coastal waters provides municipal and small scale fishermen with a wider area within which to operate fishing boats of three (3) GT or less, and with opportunities for increasing their catch per unit effort.

Other legal texts concern specific aspects of commercialisation of shrimps, for instance, - The exportation of live pond-raised prawns (except the fry, fingerlings, and spawners) is authorized provided that the individual weight of it is no more than 60 grams or - The prohibition on the importation of live shrimp and prawn of all stages.

4.1 Previous/Existing Regulations/Policies Affecting the Shrimp Resource

4.1.1 National Fishing Ordinances

Mesh size regulation. Except for capturing Penaiedae for pound-cultture ("sugpo fry" () and small but relatively matured species such as Acetes (alamang), a Fisheries Admnistrative Order (FAO) No. 155 (1986) prohibits the use of fishing gears with fine mesh nets.

Seasonal closure. Prior to the enactment of R.A. 7160, otherwise known as the Local Government Code of 1991, several national fishery administrative orders were issued to close trawl operation in some parts of the country (se list below).

Regulation of trawl operation in Maqueda, Villareal and Carigara Bays, inlcuding Zumarraga Channel (FAO 37, s. 1954, as amended up to 73-2 superseded); Manila Bay (FAO 54, s. 1959 superseded; FAO 99, s. 1970 superseded; FAO 175, s. 1991); Cancabatoc, City of Tacloban (FAO 58 s. 1959); northern and northwestern waters of Bohol for 5 years period (FAO 62, s. 1960 expired); prohibition of trawl fishing in Bohol for a period of one year (FAO 104, s. 1971 expired); 5 year closed season for operation of trawl in Bohol (FAO 130, s. 1981 expired); closed season for trawl operation in Negros Oriental (FAO 132, s. 1981 superseded); closed season of 5 years for commercial trawl in waters of Quezon province (FAO 134, s. 1981 expired/superseded); closed season of 5 years in waters of Palawan (FAO 137, s. 1982 expired/superseded); closed season of 5 years for operation of trawl in waters of Batangas (FAO 142, s. 1983-expired);

Import and Export Regulation of Live Shrimps/Prawn

Ban on exportation of live gravid shrimps of genus Penaeus (FAO 141, s. 1982-amended by FAO 143); ban in exportation of live prawns (sugpo) of the species Penaeus monodon (FAO 143, s. 1983); the above mentioned texts regarding the exportation of live pond-raised prawns not more than 60 g per piece (FAO 143-5, s. 1983 subsisting) or the prohibition of the importation of live shrimp and prawn of all stages (FAO 189, s. 1993).

4.1.2 Municipal Fishing Ordinances

As the enforcement of fishery laws in the municipal waters has been devolved to the Municipal Government pursuant to section 17 R.A. 7160, specific fishery measures are now formulated and enforced by the local government. Concerning shrimp fisheries, the most common regulation consists in the banning of trawl fishing operations in their jurisdictional waters.

Regularly monitored shrimp trawl fishing grounds has promulgated measures as follows:

San Miguel Bay

Some municipalities among the seven in the Bay area, may allow operation of baby trawls (less than 3 gross tonnes) but only beyond 7 km from the coastline (Municipality of Calabanga, Province of Camarines Sur as per M.O. 95-06); other, such as Mercedes, prohibit trawling within 15 km from the coastline (M.O. 65-95). However, it is worth mentioning that capturing sugpo fry for pond rearing is authorized everywhere.

Ragay Gulf

There are 8 municipalites in the area. Trawling activities can be metin two municipalities only. The use of motorized pushnet is prohibited by certain municipalities while other limits commercial trawl operations. One of the municipalities prohibits the use of fishing gears with less than 3 cm mesh size.

Sorsogon Bay

One municipality out of six, only, (Sorsogon) authorizes baby trawl fishing. In general, authorized grounds for trawling are beyond 15 km from the coastline.

5. RESEARCH ACTIVITIES, PAST AND FUTURE

According to Villadolid and Villaluz (1951) Penaeus monodon is caught in the open sea in trawls, with other shrimp species but always outnumbered by the other species. P. monodon, is also commonly found throughout coastal areas, tidal rivers and estuaries. Several Penaeidae occur abundantly in mangrove swamps.

In the Manila Bay area, the bulk of the Penaeus monodon fry for aquaculture comes from the Cavite side of the Bay (especially from the towns of Ternate and Naic). Other important sugpo fry grounds are Bauan and Balayan in Batangas, Bulacan, Pampanga, Dasol Bay in Pangasinan, the Ilocos Provinces, San Jose in Occidental Mindoro, Quezon province, Paracale in Camarines Norte, Capiz, Carigara in Leyte, Maqueda Bay in Samar, Guimaras in Iloilo, Panguil Bay in Ozamis City, Cotabato, Cagayan de Oro area and Sibuguey Bay.

Small brackishwater shrimps called Acetes (Alamang) are fished in most parts of the country when winds blow towards the land. Another variety of small shrimp known as "Atya" is found in Lake Taal and the Pansipit river. Other shrimps belonging to the same family, Atyidae, are caught in the Central Visayas.

Biology of Penaeid Shrimp in the Visayan Sea

In 1976/77, Aprieto and Ingles conducted a study on the Biology of Penaeid Shrimp in the Visayan Sea (in the center of the country). It included: species composition and relative abundance in the catches, area and seasonal distribution of shrimps, in general, some aspects of the biology of major shrimp species and the ecological factors that may affect shrimp distribution and abundance in the Visayan Sea.

A survey was carried out by trawling on board a 190 GT research and training vessel (the M/V Albacore belonging to the UP College of Fisheries), from August 1976 to March, 1977. The trawl used was a two-seam trawl, 22 m wide and 46.5 m long with a mesh size of 3.0 cm in the codend.

About 13,600 kg of fish and 2,400 kg of invertebrates, of which about 100 kg or 4.24% were shrimps, were caught within eight months. It is worth observing that the shrimp catches were quite low compared to those of commercial trawlers operating on the area which average 10%-12% of shrimp in the total catch. Of the shrimps caught, 88.8 kg or 91% belonged to Subfamily Penaeidae, namely: Penaeus semisulcatus, Penaeus monodon, Penaeus teraoi, Penaeus longistylus, Penaeus indicus, Penaeus latisulcatus, Metapenaeus intermedius, Trachypenaeus fulvus, Parapenaeus longipes and Metapenaeopsis sp: and the rest were non-Penaeidae. Among these, Trachypenaeus fulvus was the most abundant and widely distributed in the study area. Next in abundance was Metapenaeopsis sp. followed by Penaeus semisulcatus.

The largest catch were observed in December and January with 1.545 kg/haul and 1.459 kg/haul respectively. Catches during night time were greater than day time.

No significant correlation was found out between oceanographic parameters such as temperature and salinity and the abundance of shrimps.

Marine Shrimp Resources of Luzon

A study on the Marine Shrimp Resources of Luzon, including relative abundance of shrimps in Manila Bay, Tayabas Bay, Lingayen Gulf and Sorsogon Bay, was conducted by del Mundo, Agasen and Ricablanca in 1990 .

The marine shrimp resources in the area consist in four genera of shrimps: Penaeus, Metapenaeus, Trachypenaeus, and Acetes. According to the results of catch and effort, it was estimated, at that time, that shrimp resources were not fully exploited by commercial trawlers.

Among the fishing grounds surveyed, Sorsogon Bay had the highest density of shrimp with 2,129 kg/km2, in December, followed by Manila Bay with 589kg/km2 in March, Tayabas Bay with 37.57 kg/km2 in February. The lowest was Lingayen Gulf with 28.29 kg/km2 in March. It was observed that shrimps were particularly abundant in these areas during the northeast monsoon. The exploitation rate of certain species was estimated in given fishing areas: for Metapenaeus dalli in Sorsogon Bay, 0.525; for Metapenaeus ensis and Penaeus indicus in Manila Bay, 0.436 and 0.55 respectively. According to these estimates, the endeavor shrimp (Metapenaeus ensis) was therefore under exploited, at that time.

It is worth mentioning that the authors of the study recommended for Sorsogon Bay area that seasonal trawling ban or closed season (from February to June each year) be established for mini trawl. It was also recommended that mangrove swamps as critical habitat for young shrimps be carefully protected and all pollution prevented.

Relative Abundance, Spawning and Recruitment of Banana Prawn (Penaeus mergueinsis) in Sorsogon Bay.
Agasen and del Mundo (1991), in their study on the Relative Abundance, Spawning and Recruitment of Banana Prawn (Penaeus merguiensis) in Sorsogon Bay, presented the trends in the catch per unit effort (CPUE) over a three-year period, 1989-1991. In this study, the fishing activities were carried out day and night. The data used were obtained from the catches of fish corrals, gillnets and mini trawls. Prawns were identified from the monthly sampling activities. The carapace length, sex and maturity were also determined.

The abundance of white shrimp (P. mergueinsis) was observed by monitoring the catch of fish corrals installed near the mouth of Cadacang River. In 1989-1991, it was observed that the peak season for white shrimp was February to July. It was also observed that the highest CPUE ranged from 45 to 46 prawns per hour. The catch also depends on the moon period of fishing: It was higher during new moon and full moon. The highest CPUE for gillnet were 67 prawns/hr in October 1989 and 48 prawns/hr in September 1990. Among the fishing gears used, the mini trawl had the lowest CPUE. The highest were 28 prawns/hr, 15 prawns/hr and 5 prawns/hr in January 1989, August 19990 and in April 1991 respectively. It was also found that the catch with fish corral, gillnet and mini trawl between 1989 and 1991 depended, in general on the amount of rainfall which probably affected either the migrations of juveniles or the settlements and survival of post larvae while the importance of water temperature was not proved (except when, in 1990, orthe catch of gillnet was found increasing with it). A number of other environmental factors were also observed but were not found being so important.

Capture Fisheries in San Miguel Bay

From July 1992 to June 1993, an assessment was conducted in San Miguel Bay in order to optimize the catches and to estimate the sustainable level of fishing effort.

The annual total catch declined from 14,687 MT in 1981 to 6,495 MT in 1993. The shrimp catches, including Penaeid and Sergestid shrimps were 4,047.6 t or 22.8% of the total catch. During this period thirty five percent (35%) of the captures were made by trawlers. Finally, it is worth mentioning that according to the assessment, the fishery resources, including shrimps, were at that time heavily exploited in San Miguel Bay

Capture Fisheries in Manila Bay

A study on Fish Stock Assessment conducted in Manila Bay from November 1992 to October 1993 with among other objectives: to make an inventory of fishing gears, an assessment of actual prevailing fishing activities in the area, to estimate the average yields and, finally, to assess the level of exploitation of economically important fish and invertebrates.

It was found out in the study that the area was exploited by about twenty one (21) municipal and commercial fishing units. The y2859e targets were demersal species and trawling was the major contributor to the fish production. A survey with trawl revealed that only 24.6% of the catch were invertebrates. In general, the statistics showed that the invertebrates (crustaceans and molluscs) might amount to 9% to 48% of the total catch.

Selective Shrimp Trawling in Manila Bay

A study on Selective Shrimp Trawling using "separator device" was recently conducted by Dickson in Manila Bay (1997). It was observed during the study that with an average catch rate of about 10 kg per hour, a 10.3% only were shrimps. By-catch species which included fishes and invertebrates other than shrimps contributed to about46.4% relative abundance) and 408.82 kg (43.3% relative abundance), respectively. Shrimp species included: brown rough shrimp (Trachypenaeus fulvus), 4.54%; tiger prawn (Penaeus semisulcatus), 3.52%; and greasy back shrimp (Metapenaeus ensis), 1.15%. It is worth mentioning that the quantities of shrimps caught were found slightly less when trawls are equipped with "separator device": a mean catch of 10.31 kg/hr against 9.79 kg/hr while the shrimps species composition was found almost similar.

Future Research Priorities

Mobile gears such as trawl and pushnet, have severe impact on fishery resources. Damage to sea bed and capacity of catching (with small meshes) all sizes of fish are some of the technological problems that need to be addressed. To prohibition of all utilization of such fishing gears may not be practically feasible because of these are well appropriate to the exploitation on this resources. However, practical solution should be found through a strong effort in technological research and development to minimize potential negative impacts.

The preservation of undersized fish when using trawls and seine nets requires in-depth studies regarding the appropriate mesh sizes for the different parts of the nets, in particular, in the codend of trawl. However, it is worth recognizing the difficulties in respect to the diversity of situations: fishing grounds, composition of the living resources, immediate constraints of the industry, etc.

It is recommended that efforts be made for an effective separation between target species and by-catch and the exclusion of endangered species such as turtles. More research is required concerning horizontal separation net panel and turtle-excluder devices. In respect to this, studies regarding the reaction of target and by-catch to trawl would have to be carried out. Important differences have already been recognized between fish swimming actively and, as such, capable of escaping through exit-holes in the upper panel of the netand shrimp rey2859eing passive with less opportunities for escaping.

When trawling is carried out for catching high-value shrimp in priority, efforts are justified to develop effective by-catch reduction devices (BRDs). A BRD based on the utilization of a square mesh window panel seems to be promising and research should be followed up in this respect. However, it is worth mentioning that, at the same time, it is essential to analyse carefully the practices of fishing operators towards by-catch in general in various shrimp fishing areas of the country. The existing demand for trash fish or by-catch and existing markets in many places have obviously to be taken into account for the monitoring of by-catch related matters. In addition, while developing any BRD, existing unavoidable by-catch (the quantities of which may vary much according to fishing grounds) have to be considered.

Another traditional fishing gear other than trawl for shrimp are gill nets. Some shrimp species (Metapenaeus dobsonii and M. ensis) are caught when their rostrum become entangled in the nets. The experience showed that to increase the catching efficiency of the gillnets on shrimp, it was worth folding the lower section of them as to making bags along the footrope.

In general, research work in fish behavior and fishing gear selectively, must be given priority. In respect to this, it should be observed that the lack of instruments for analysis and recording of environmental conditions is a difficulty in Fishing Technology R & D.

Tests/experiments of technologies having proven effectiveness in other countries is another interesting option.

6. IMPACT AND PERCEPTION ON SHRIMP EXPLOITATION

The exploitation of shrimps resources in the Philippines usually results to catches of other species, in greneral, including immature fish. As an average, trawlers in the Philippines have catches of shrimp to fish ratio ranging 19 to 10% or even less.

A lot of problems results from actual shrimp fisheries in the country. Mobile gears such as trawl and pushnet have severe impact on fishery resources, including through unwanted catch. Very fine meshed nets are used. Small-sized fish, invertebrates and mollusks,as unavoidable catch in addition to shrimps, are systematically discarded. In general, the shrimp trawling operations affect the breeding cycles of fish, shrimps and other sea-bottom dwellers. Observation of the catches already shows changes regarding species composition as well as sizes of fish. High valued species are less abundant. The continuous plowing of the bays and gulfs kills bottom organisms and prevent other to settle. In areas where intensive trawling has been carried out for a while, increase population of scavenges such as small crabs are found. At the same time, the overall fishing effort on shrimp is increasing and there is strong competition among shrimp trawlers in most bays and gulfs (the open-access situation still prevails).

The habitat of shrimp is characterized by soft muddy bottom. Many species, as by-catch, are uprooted from their natural habitats. Trawl fishing stirs up sediment that maybe transported to adjacent ecosystems and cause the suffocation of corals, shells and other marine organisms.

The negative environment and socioeconomic impact of trawling, including for shrimps, have long been experienced. The increase of trawling fleets increased problems between trawling and non-trawling fishers on the same fishing grounds. A common complaint from the non-trawling fishers is that once an area has been trawled, they can hardly catch a quantity enough for the subsistance of their families. Concerned with the environment and fishery issues, the small non-trawl fishers are requesting the closure of the major bays and gulfs to trawling. Tension between trawling and non-trawling fishers is now creating serious problems in various areas and sometimes lead to difficult relationships between fishers and administration whennon-trawl fishers are alleging that the local government officials favour the trawlers.

In general, trawl fishing is perceived by many as a destructive practice and a number of fishery researchers, officials and NGOs are recommending that shrimp fishing grounds are reserved for small fishers and the bays are closed from trawl. It is practically recommended the development of comprehensive fishery management plans aiming to phasing out trawl fishing from bays and gulfs.

It is worth reminding that after an enormous expansion from as early as 1960's, the trawl industry experienced a decline. The decrease of the catch per unit of effort, the average size of fish which are landed and the quality of catch have progressively worried all various stakeholders. Several fishing grounds in the country are now recognized officially as overfished and ecologically impaired.

Catch efficiency data concerning target and incidental catch, and other information about trawling were collected from previous resource and ecological assessments in a number of bays potentailly endangered, and on area known as "traditional trawl fishing grounds", such as Sorsogon Bay, San Miguel Bay, Ragay Gulf and Manila Bay. A brief review on the status of trawl fisheries in pre-selected sites of Luzon Island, Philippines especially San Migule Bay is given below.

An Opinion Survey regarding Environmental Changes and Fisheries in the San Miguel Bay

The study was carried out on the seven municipalities of the San Miguel Bay; both officials and fishery operators were interviewed.

Almost 90% agreed that during the past several years, productivity of the San Miguel Bay has been declining as the increase in fishing effort with both trawls and other small scale fishing methods could not result in an increased catch. The decrease in the productivity of the fisheries did not only affect the fishers and their families but their whole communities and even other people indirectly depending on fishing. In general, commercial and municipal trawling are considered as y2859e cause of problem; many people point out that "trawling is destructive to the environment" and not a selective fishing method because of the fine meshes which are used retaining all fish regardless of size. About 56% of the people alleged that the use of illegal and destructive fishing methods also contributes to the decline of production.

About 15% of the respondents reported damages to coral reefs in the San Miguel Bay's mouth; the coral reef areas would be affected by both trawling and dynamite fishing.

Conflicts regarding the use of marine resources

Conflicts between small fishers and trawlers have intensified since trawling activities have become more and more intensive in the bay. It was reported that trawling operations often damage nets laid by small scale fishers; fishers who target fish on coral reefs are also complaining that their gear are frequently destroyed.

A number of small scale fishers are also complaining about the use of explosives, chemicals and nets with fine meshes.

Fisheries Law Violations and Enforcement Problems

Eighty percent of the informants reported that the most violated fisheries law in the bay was the trawling ban. As early as 1950, an annual closed season for trawlers was established. While the Presidential Decree 1015 prohibited the operation of trawls using boats 3 GT or less, baby trawls could be used in areas 4 fm. deep or more if authorized by existing municipal ordinances. However, it is worth mentioning that in 1983, two Municipalities only had authorized baby trawls and one of them withdrew its authorization in 1987.

Enforcement Problems and Solutions

Enforcement of existing fisheries regulations in the bay area is considered as inadequate due to lack of staff, of surveillance vessels and of other facilities to properly monitor areas where illegal fishing is rampant.

Labor and employment opportunities

Small-scale fishing activities usually employ family labor in priority. Family manpower is maximized, precluding expenses for hired labor. Most, if not all, family members participate in the preparation of nets and other paraphernalia before setting out to sea and making or mending of nets.

In 1982, full or part time fishing was reported to be a major source of income in San Miguel Bay. Fishing alternatives in other sectors did not have the capacity to absorb labor from the fisheries sector or even to serve as a supplementary source of income for small fishers and their families.

Environmental Issues

Anyway, it was observed that the most important and urgent issue concerning the environmental status of San Miguel Bay was resource depletion (as shown by the general decrease in the catch). The decline in the bay's productivity was attributed to the use of depletive and destructive fishing methods, i.e. trawling, the use of dynamite or poisons. Weakness of fishery regulation, in general, and its implementation is also a serious problem.

7. NATIONAL IDENTIFICATION OF PRIORITY ISSUES REQUIRING ACTIONS

If reference is made to both recent surveysand published documents, the present exploitation of the shrimp resource is non-sustainable, at least, due to the catch of non-target species, immature fish, endangered species. It is therefore necessary to reduce or eliminate the capture of non-target species especially juveniles of commercially important food fishes.

Discussions among shrimp operators from Manila Bay, Ragay Gulf and San Miguel Bay, including with the participation of fishery administration and researchers had led to some recommendation such as, in priority to conduct experiment on various juveniles and by-catch reduction devices with the participation of affected stakeholders.

All or majority of the trawl operators including the crew of the vessel targeting or, only, catching shrimp resource lack awareness on the importance of other species caught during their operation. It is clear that discarding a lot of immature fish including crustaceans and mollusc during the course of operation make their work easy in the short terms but also assumed that such practice is, in the medium to long term, damaging to the resource and habitat. There must therefore be a strong effort made to increase the awareness of all concerned, in priority to fishers, concerning proper management of fishery resources, regulations regarding by catch and discards in trawl fisheries, the effect of catching immature fish and other species, including endangered ones, the use of by-catch and juveniles excluder devices for the long term sustainability of the fishing resources and their exploitation.

Considering the effect shrimp trawls have on other resources and with regards to finding solutions for reducing by-catch and increasing the target species, it is necessary that alternative fishing gears such as gillnets and trammel nets should be tried to assess their catching efficiency and selectivity. Technologies from other countries having shown being effective and selective should be considered for a transfer to the stakeholders in the country. At the same time, it would be suitable to look, as much as possible, for management measures other than closed season, such as limited entry for harvesting the shrimp resources so that other resources which is caught with shrimp will be reduced or eliminated. Besides, it is worth mentioning problems on certains shrimp fishing grounds such as Manila Bay: large quantities of wastage, including a lot of plastic material which are caught during fishing operations, up to 60% of the total catch, have to be sorted on the shrimp trawlers'deck which takes time leading to some deterioration of the shrimp and fish; it would be necessary that the national government and concerned agencies formulate programs to solve this problem.

The characteristics of existing shrimp trawlers, e.g. size and arrangement of the deck, and practices and attitude of the crews should be carefully considered when planning the introduction of by-catch minimization technologies. Even if fishery operators are involved in all discussions at the early stage of the development of by-catch reduction technology, it is worth keeping in mind that the introduction of such a technology will lead to some extra-cost. There is chance that many fishers be, for this reason, reluctant. It is, first, recommended that pilot tests involving the cooperation of shrimp trawlers be conducted.

8. A NATIONAL PLAN OF ACTION

While being dragged on the seabed, bottom trawls used for shrimp have some potentially negative impact on the habitat. More important right now is that shrimp trawls usually catch a significant amount of fish and invertebrates by-catch and that a large part of it is discarded at sea. The catch of juveniles and low-value fish in large quantities is un-sustainable. Therefore reduction of by-catch, juveniles in particular, should be given appropriate and immediate attention. It is therefore necessary to have available data on by-catch specially discards.

A relevant Plan of Action could include three y2859e components.

The impact of trawling is not well documented, in general. The first component would be the careful evaluation of the level of impact of shrimp trawling fisheries on the environment, both habitat and biodiversity. Four to six fishing grounds would be identified where shrimp are caught by trawlers and other gears. The study would consist in boarding shrimp trawlers to collect data on by-catch and discards and, as far as possible, to make observation regarding possible impact to the seabed, etc. Three to six months would have to be allocated to each fishing ground. At the same time, attention would have to be paid to the socio-economic conditions in various areas in the country since, as a matter of fact, these are very important factors for the perception of impact (short and long terms) of activities. A study over three fishing areas would have to be carried out in this respect.

The second component would be the design, testing and demonstration of by-catch and juvenile reduction devices (several designs imported from France (IFREMER), Australia and Thailand (the Southeast Asia Fisheries Development Centre (Training Department) SEAFDEC-TD) on board shrimp trawlers on various shrimp fishing grounds. Several type of BRDs would be constructed and tested on board commercial vessels in order to determine the most efficient in terms of shrimp retainment and escapement of by-catch specially juvenile of fish and endangered species. At the same time, alternative fishing gears/methods would be considered and incentives for it will have to be given to shrimp harvesting fishermen.

The third component would be the extension and dissemination in the concerned shrimp fisheries of the best and appropriate technology with the participation of leading fishermen/operators. The strategy could be to prepare a list of association of the fisherfolk engaged in shrimp harvesting and to give the responsibility for the introduction of environmentally friendly selective fishing gears (demonstration and extension work) to these groups. It is worth mentioning that a monitoring and evaluation of the technologies over a long enough period would be necessary with possible changes and adjustments to the devices as required to solve specific problems. Some involvement of local school of fisheries in the area would also be recommended, in particular for supporting research and monitoring.

By the end of the process, some policy for exploiation of the resources of shrimp harvesting would be to be formulated as the basis in the sustainable/responsible exploitation of the resource.

Finally, it is worth mentioning that networking with other countries involved in similar process for introduction of by-catch reduction technologies would be very suitable for exchanges of information on technical matters as well as on strategy and implementation programme.

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