Fishery Traps (Gargours) in Saudi Territorial Waters of the Arabian Gulf
Adel Ahmed Tharwat and Abdel Rahman Al-Gaber Department of Aquatic Resources Development,
Faculty of Agriculture and Food Sciences,
King Faisal University, P.O. Box 420, Hofuf 31982, Saudi Arabia [email protected]
Abstract. Despite of the economic importance of the traps (locally named Gargours), operating in the Saudi traditional fishery of the Arabian Gulf, scatter studies dealt with this fishing gear. So, the present work describes and evaluates all subjects related to the catcha- bility of the fishery traps and their impacts on productivity of fish biomass. The present work is achieved through the research project number 5001 (1425-1426 H) financial supporting from deanship of scientific research, King Faisal University. The catch analysis (systematic identification, quantity and quality), the catch per unit effort (CPUE) and the seasonality of fishing (the relative abundance during the year) were studied, as well as, some biological aspects of major fish species were investigated. Also, temperature and salinity of the surface Gulf water of the fishing area were measured. The results indicated that the water temperature was the major factor affecting the fishing rates during the year, especially on the small traps. The small traps have a passive effect on the stock biomass that contributed to more selection of immature fishes. The estimated annual percent- age of lost traps was higher for large boats than of small boats. Many valuable fish and crustacean species that belong to Lethrinidae, Serranidae, Lutjanidae, Siganidae, Carangidae, Haemulidae, Sparidae, Mullidae, Platycephalidae and Portunidae constituted the majority of trap catch. Some recommendations were given for development of fishery traps in Saudi territorial waters of the Arabian Gulf.
Keywords: Fishery traps, Catch per unit effort, Fishing gears, Biolog- ical parameters, Gargours, Arabian Gulf, Saudi Arabia.
13
Introduction
Saudi Arabia’s strongest advantage is it has 2,400 km coastline, 1800 km on the Red Sea and 600 km on the Arabian Gulf. The Arabian Gulf is connected with the Gulf of Oman through the Strait of Hormuz. Local fish supplies in 2004 were approximately 66591 metric tons, consisting of 55419 MT from the marine fisheries (83%) and 11172 MT from aquaculture (17%). The production of the Red Sea, Arabian Gulf and International waters were 20448, 34961 and 10 MT, respectively. Approximately, all landings (99.78%) of the Arabian Gulf come from the traditional fisheries (FSSA, 2006). The traditional fishery refers to the fishing boats of 5-20 meters in length, that operate without the fishing technology equipments, while, the industrial fisheries use only shrimp trawl net and contributes only about 0.22% of the total landings from the Gulf. Four main fishing gears were used in traditional fisheries, these are traps, shrimp trawl, then large and small meshsize gillnets, in addition, three other types (handline, longline and trolllines) were used.
Traps are the most dominant fishing gear used in the Arabian Gulf. Some authors dealt with fisheries aspects in Saudi Arabia (Peacock and Alam, 1980;
Kedidi et al., 1984; Olsen et al., 1996; PERSGA, 1997 and Tharwat, 2003, 2005a
& b). The present study aims to describe and evaluate the status of fishery traps including; the catch analysis (systematic identification, quantity and quality), the catch per unit effort (CPUE), the seasonality of fishing (the relative abundance during the year), some biological aspects of harvested fish species. Also, tempera- ture and salinity of the surface Gulf water of the fishing area were measured.
Materials and Methods
Monthly fishing trips by large and small fishing boats using traps were performed to collect data and fish specimens from Saudi territorial waters of the Arabian Gulf during 2004-2005. The present work is achieved through the research project number 5001 (1425-1426 H) financial supporting from dean- ship of scientific research, King Faisal University. The catch of both large and small traps was recorded and identified to species according to Carpenter et al.
(1997). A representative sample for the common species is taken for biological investigation. Surface water temperature and salinity of the fishing area were measured during the fishing trips. Each fish was measured for length (cm) and weight (g), and then it was dissected to identify sex, maturity stage, stomach content, then remove viscera to record gutted weight (g). Fresh gonads were removed and visually inspected for size, colour, vascularization and presence of milt and oocytes to determine the macroscopic (staged by eye) staging of fresh ovaries and testes followed Collins et al., 1998. Length at which 50% of fishes reach sexual maturity (length at first sexual maturity, Lm50) was estimated by
Fig. 1. The traditional catches (metric ton, MT) by type of fishing gears operating in Saudi territorial waters of the Arabian Gulf during 1995-2004.
maturation curve method (Brule et al., 1999 and Burgos, 2001). The historical data of catch & effort represented by the number of traps were colleted from the Fisheries Statistics of Saudi Arabia (FSSA, 1995~2004) to estimate the catch per unit effort (CPUE). CPUE is the catch of fish in weight (kg), obtained by a defined unit of fishing effort were estimated as described in Sparre and Venema (1992). The CPUE all over ten years (1995-2004) was investigated to assess the relative abundance of different fish stocks and fishing effort trend of the Arabian Gulf. Means and standard deviation (m ± SD) were computed for all data during the different years by statistical software program (SAS, 1990).
Results and Discussion Description of the Fishery
Figure 1 shows that traps are the most dominant type of traditional fishing gears throughout the years 1995-2004; their catch attains 14589 MT in 2004 and represents 41.82% of the total traditional catch in the Arabian Gulf. It decreased by 387 MT or 2.58% in 2004 than the previous year. The traps (local name gargours), shrimp trawl, then large and small meshsize gillnets are the major types of traditional fishing gears operate in the Arabian Gulf. These fish- ing gears harvested 89.4% of the total traditional catch, while the rest consisting 10.6% of the total catch harvested by handline, longline and trolllines. How- ever, the total catch of the Arabian Gulf was 34961 MT in 2004, this total land- ing resemble a small increase in fishing quantity compared with last year. The traditional catch gradually increased during 1999-2004 to attain 34884 MT consisting 99.78% of the total. This increase is due to the increase in landing of
Fig. 2. The traps fishing effort (%) of large fishing boats operate in Saudi territorial waters of the Arabian Gulf during 1995-2004.
Fig. 3. The traps fishing effort (%) of small fishing boats operate in Saudi territorial waters of the Arabian Gulf during 1995-2004.
some major species in the traditional sector, and the increase in number of fish- ing trips. While, the landing of industrial fishery declined to 77 MT represent- ing 0.22% of the total (FSSA, 2006) which, it obtained from shrimp trawling only. This sharply declined due to the overfishing throughout the previous years. Figures 2 and 3 displayed the fishing effort (%) as the number of traps used, fishing days and fishing trips during 1995-2004 for large and small fish- ing boats, respectively. The number of traps used in the large boats was more fluctuated with an increased pattern than in the small boats.
Table 1. Average monthly catch per unit effort as (kg/trap, kg/fishing day) and catch season- ality (kg/month) for both large and small traps operate in Saudi territorial waters of the Arabian Gulf during 2005.
Season Month Large traps Small traps
kg/trap kg/day kg/month kg/trap kg/day kg/month
Dec. 9.0 450 6750 2.9 145 2175
winter Jan. 6.7 335 5025 1.8 90 1350
Feb. 7.5 375 5625 2.3 115 1725
mean 7.7 386.7 5800 2.3 116.7 1750
Mar. 17.9 895 13425 5.8 290 4350
spring Apr. 24.2 1210 18150 4.2 210 3150
May 22.0 1100 16500 2.7 135 2025
mean 21.4 1068.3 16025 4.2 211.7 3175
Jun. 14.5 725 10875 4.0 200 3000
summer Jul. 16.7 835 12525 2.9 145 2175
Aug. 18.2 910 13650 2.7 135 2025
mean 16.5 823.3 12350 3.2 160.0 2400
Sep. 21.4 1070 16050 6.9 345 5175
autumn Oct. 18.2 910 13650 5.0 250 3750
Nov. 13.7 685 10275 3.8 190 2850
mean 17.8 888.3 13325 5.2 261.7 3925
Overall mean 15.8 792 11875 3.8 187 2850
Annual total – – 142500 – – 34200
Catch Per Unit Effort (CPUE) and Seasonality
Table 1 shows the average monthly catch per unit effort as (kg/trap and kg/
fishing day) and catch seasonality (kg/month) for both large and small traps operating in Saudi territorial waters of the Arabian Gulf. It is obvious that CPUE sharply decreased for both large and small traps during Winter season (7.7 and 2.3 kg/trap, respectively), this could be attributed to the decline in all physiological activities of fishes during relatively cold temperature (11-15ºC).
The maximum CPUE of large traps occurred during the spring season followed by autumn and then moderate value obtained during summer season (21.4, 17.8 and 16.5 kg/trap, respectively). However, the maximum CPUE of small traps occurred during the autumn season followed by spring and then moderate value obtained during summer season (5.2, 4.2 and 3.2 kg/trap, respectively). This variation in the CPUE between large and small traps during seasons of the year could be attributed to the different size of the trap funnel opening and the differ-
ent ecological factors between deeper and shallow waters of the fishing areas.
The monthly changes of catch per unit effort (kg/trap) according to the average monthly temperature (Cº) and salinity (‰) of Saudi territorial waters of the Arabian Gulf are shown in Fig. 4 and 5. On the other hand, the catch per unit effort (kg/trap and kg/ fishing day) of both large and small fishing boats used traps in Saudi territorial waters of the Arabian Gulf during 1995-2004 were
Fig. 4. Monthly catch per unit effort (kg/trap) according to the average temperature of Saudi territorial waters of the Arabian Gulf.
Fig. 5. Monthly catch per unit effort (kg/trap) according to the average salinity (‰) of Saudi territorial waters of the Arabian Gulf.
shown in Fig. 6 and 7, which are related to the effort as the fishing day and the number of traps, respectively. The data indicated that average catch/fishing day relatively fluctuated in the large boats during the years with a relative increase at 2004, while it tended to increase in small boats to attain the same quantity at 2003 followed by slight decline at 2004 (Fig. 6). On the other hand, the average CPUE as catch/trap highly decreased in the large boats, but it relatively increased in small boats during the years to attain approximately equal value (Fig. 7) at 2003 then both declined at 2004. In addition, it can be noticed from
Fig. 6. The catch per unit effort (kg/fishing day) of large and small fishing boats operate in Saudi territorial waters of the Arabian Gulf during 1995-2004.
Fig. 7. The catch per unit effort (kg/trap) of large and small fishing boats operate in Saudi territorial waters of the Arabian Gulf during 1995-2004.
the trips observations that the loss percentage of traps was higher in large boats (about 12%) than in small boats (about 8%), this may be due to the different ecological factors including water moving in deeper and shallow waters of the fishing areas.
Catch Composition
In the present work (Tables 2 and 3), it was found that all harvested fish &
crustacean species by large and small traps belong to 10 major families, and the catch composition was the same in both large boats (mainly using large traps in deep waters) and small boats (mainly using small traps in shallow waters). The only difference was in the fish size and quantity, where the mean fish sizes obtained by the large traps were bigger than mean fish sizes obtained by the small traps. This could be attributed to the variation in size of the trap funnel opening and fishing grounds. Fig. 8 shows the percentage of major fish and crustacean groups caught by traps operating in the Saudi territorial waters of the Arabian Gulf during 1995-2004. It is obvious that emperors, sea breams, group- ers, scads/jacks/ and trevallies, rabbit fishes, snapper and others (mainly crabs, Grunt, goatfish and bartail) were the common species in the catch throughout 1995-2004. By following the CPUE of the groups, it was noticed that the rela- tive abundance of these groups fluctuated through years.
Table 2. Catch composition of major fish and crustacean families harvested by large traps operate in Saudi territorial waters of the Arabian Gulf during 2005.
No. Family Catch composition
kg %
1 Lethrinidae (Emperor) 37636 26.4
2 Serranidae (Grouper) 25946 18.2
3 Carangidae (Trevally) 24378 17.1
4 Lutjanidae (Snapper) 13686 9.6
5 Siganidae (Rabbitfish) 10692 7.5
6 Haemulidae (Grunt) 8981 6.3
7 Portunidae (Crab) 7556 5.3
8 Sparidae (Seabream) 6558 4.6
9 Mullidae (Goatfish) 4562 3.2
10 Platycephalidae (Bartail) 2566 1.8
Total 142560 100.0
Fig. 8. Catch composition of the traps fishing gear (Gargours) operating in Saudi territorial waters of the Arabian Gulf during 1995-2004.
Biological Parameters
Fishes belong to each family were classified by species (Tables 4 and 5).
Scientific and English names, average fish length (cm), average fish weight (g), length at first maturity sexual (Lm50) and their feeding habits. The present
Table 3. Catch composition of major fish and crustacean families harvested by small traps operate in Saudi territorial waters of the Arabian Gulf during 2005.
No. Family Catch composition
kg %
1 Lethrinidae (Emperor) 7353 21.5
2 Carangidae (Trevally) 6943 20.3
3 Siganidae (Rabbitfish) 5575 16.3
4 Serranidae (Grouper) 4138 12.1
5 Portunidae (Crab) 3488 10.2
6 Lutjanidae (Snapper) 2668 7.8
7 Haemulidae (Grunt) 1881 5.5
8 Sparidae (Seabream) 1402 4.1
9 Mullidae (Goatfish) 547 1.6
10 Platycephalidae (Bartail) 205 0.6
Total 34200 100.0
Table 4. Fish and crustacean families of large traps identified by species harvested from Saudi territorial waters of the Arabian Gulf, and some biological aspects. Species Mean lengthMean weightLength at Family (cm ± SD)(g ± SD)first sexual Feeding habit English name Scientific namematurity (cm) Spangled emperorLethrinus nebulosus44 ± 5.1 656 ± 12.435Mollusks, crustaceans & echinoderms LethrinidaeSnubnose emperorLethrinus borbonicus33 ± 3.0 342 ± 11.029Mollusks, crustaceans & echinoderms Pinkear emperorLethrinus lentjan39 ± 4.1 360 ± 12.630Mollusks, crustaceans & echinoderms Smalltooth emperorLethrinus microdon49 ± 5.3 567 ± 14.233Mollusks, crustaceans & echinoderms Redmouth grouperAethaloperca rogoa50 ± 3.2 453 ± 9.234Small fishes & mollusks SerranidaeOrangespotted grouperEpinephelus coioides56 ± 4.32268 ± 17.048Fish & crustaceans Whitespotted grouperEpinephelus caerulepunctatus52 ± 3.02304 ± 16.245Fish & crustaceans Areolate grouperEpinephelus areolatus38 ± 2.9 589 ± 10.531Fish & crustaceans Indian threadfishAlectis indicus48 ± 5.1 858 ± 16.130Small fishes, squids & crustaceans Longnose trevallyCarangoides chrysophrys54 ± 5.71020 ± 18.035Small fishes, squids & crustaceans Golden trevallyGnathodon speciosus61 ± 4.8 565 ± 9.128Crustaceans, mollusks & small fishes CarangidaeTalang queenfishScomberoides commersonianus54 ± 5.5 445 ± 10.334Small squids & small fishes Orangespotted trevallyCarangoides bajad47 ± 4.3 286 ± 8.132Small squids & small fishes Bigeye trevallyCaranx sexfasciatus50 ± 4.0 450 ± 8.930Small fish & crustaceans Giant trevallyCaranx ignobilis67 ± 6.71079 ± 12.637Small fish & crustaceans
Table 4. Contd. Species Mean lengthMean weightLength at Family (cm ± SD)(g ± SD)first sexual Feeding habit English name Scientific namematurity (cm) Blackspot snapperLutjanus fulviflamma30 ± 2.5225 ± 6.720Small fish & crustaceans Lutjanidae Ehrenberg’s snapperLutjanus ehrenbergii25 ±2.1152 ± 5.319Small fish & crustaceans Malabar blood snapperLutjanus malabaricus57 ± 2.42190 ± 15.939Small fish & crustaceans Humphead snapperLutjanus sanguineus53 ± 2.32230 ± 15.336Small fish & crustaceans Siganidae White spotted spinefootSiganus canaliculatus28 ± 2.0 220 ± 4.619Algae & Sea grasses Streaked spinefootSiganus javus24 ± 2.1 143 ± 3.218Algae & Sea grasses Sordid sweetlipPlectorhinchus sordidus44 ± 3.6 236 ± 6.232Small crustaceans & bivalves Haemulidae Silver gruntPomadasys argyreus38 ± 2.6 210 ± 5.427Benthic invertebrates & fish Blackspotted rubberlipPlectorhinchus gaterinus39 ± 3.2 290 ± 5.927Small fish & crustaceans Portunidae Blue swimming crabPortunus pelagicusCL 11 ± 1.9 160 ± 2.3–Small fish & invertebrates Yellowfin seabreamAcanthopagrus latus32 ± 2.5 196 ± 4.124Echinoderms, worms, crustaceans & mollusks Onespot seabreamDiplodus sargus kotschyi22 ± 1.2 129 ± 2.618Algae & small invertebrates Sparidae Silvery seabreamSparidentex hasta30 ± 2.3 190 ± 4.024Small fish & invertebrates Haffara seabreamRhabdosargus haffara31 ± 2.0 132 ± 3.321Benthic invertebrates Twobar seabreamAcanthopagrus bifasciatus35 ± 2.1 289 ± 4.725Small fishes & invertebrates Mullidae Yellowstripe goatfishMulloidichthys flavoleneatus24 ± 1.7 92 ± 2.016Benthic invertebrates Cinnabar goatfishParupeneus heptacanthus25 ± 1.6 107 ± 2.217Benthic invertebrates Platycephalidae Bartail flatheadPlatycephalus indicus55 ± 3.5 405 ± 8.640Benthic invertebrates & fishes
Table 5. Fish and crustacean families of small traps identified by species harvested from Saudi territorial waters of the Arabian Gulf, and some biological aspects. Species Mean lengthMean weightLength at Family (cm ± SD)(g ± SD)first sexual Feeding habit English name Scientific namematurity (cm) Spangled emperorLethrinus nebulosus32 ± 4.3 382 ± 12.135Mollusks, crustaceans & echinoderms LethrinidaeSnubnose emperorLethrinus borbonicus24 ± 3.2 199 ± 10.029Mollusks, crustaceans & echinoderms Pinkear emperorLethrinus lentjan27 ± 3.5 210 ± 10.530Mollusks, crustaceans & echinoderms Smalltooth emperorLethrinus microdon33 ± 5.1 331 ± 12.333Mollusks, crustaceans & echinoderms Redmouth grouperAethaloperca rogoa34 ± 3.2 264 ± 9.234Small fishes & mollusks SerranidaeOrangespotted grouperEpinephelus coioides35 ± 4.0 645 ± 13.648Fish & crustaceans Whitespotted grouperEpinephelus caerulepunctatus32 ± 3.5 760 ± 15.245Fish & crustaceans Areolate grouperEpinephelus areolatus26 ± 2.7 294 ± 8.631Fish & crustaceans Indian threadfishAlectis indicus32 ± 4.9 429 ± 12.030Small fishes, squids & crustaceans Longnose trevallyCarangoides chrysophrys36 ± 4.7 510 ± 14.335Small fishes, squids & crustaceans Golden trevallyGnathodon speciosus41 ± 4.2 282 ± 7.428Crustaceans, mollusks & small fishes CarangidaeTalang queenfishScomberoides commersonianus46 ± 5.5 223 ± 7.234Small squids & small fishes Orangespotted trevallyCarangoides bajad31 ± 3.5 162 ± 8.732Small squids & small fishes Bigeye trevallyCaranx sexfasciatus34 ± 3.6 235 ± 9.130Small fish & crustaceans Giant trevallyCaranx ignobilis49 ± 7.0 536 ± 12.037Small fish & crustaceans
Table 5. Contd. Species Mean lengthMean weightLength at Family (cm ± SD)(g ± SD)first sexual Feeding habit English name Scientific namematurity (cm) Blackspot snapperLutjanus fulviflamma20 ± 2.4126 ± 6.520Small fish & crustaceans Lutjanidae Ehrenberg’s snapperLutjanus ehrenbergii17 ±2.0 87 ± 5.319Small fish & crustaceans Malabar blood snapperLutjanus malabaricus36 ± 2.9 711 ± 6.039Small fish & crustaceans Humphead snapperLutjanus sanguineus34 ± 2.5728 ± 5.836Small fish & crustaceans Siganidae White spotted spinefootSiganus canaliculatus20 ± 2.1 123 ± 4.219Algae & Sea grasses Streaked spinefootSiganus javus17 ± 2.0 83 ± 3.018Algae & Sea grasses Sordid sweetlipPlectorhinchus sordidus30 ± 3.6137 ± 6.132Small crustaceans & bivalves Haemulidae Silver gruntPomadasys argyreus26 ± 2.4 120 ± 7.527Benthic invertebrates & fish Blackspotted rubberlipPlectorhinchus gaterinus27 ± 3.1 165 ± 3.127Small fish & crustaceans Portunidae Blue swimming crabPortunus pelagicusCL 8 ± 1.6 120 ± 2.3–Small fish & invertebrates Yellowfin seabreamAcanthopagrus latus22 ± 2.3 112 ± 3.024Echinoderms, worms, crustaceans & mollusks Onespot seabreamDiplodus sargus kotschyi15 ± 1.0 76 ± 2.718Algae & small invertebrates Sparidae Silvery seabreamSparidentex hasta20 ± 2.1 106 ± 4.124Small fish & invertebrates Haffara seabreamRhabdosargus haffara21 ± 2.0 77 ± 3.221Benthic invertebrates Twobar seabreamAcanthopagrus bifasciatus23 ± 2.2 175 ± 5.225Small fishes & invertebrates Mullidae Yellowstripe goatfishMulloidichthys flavoleneatus16 ± 1.7 69 ± 2.416Benthic invertebrates Cinnabar goatfishParupeneus heptacanthus17 ± 1.9 75 ± 2.517Benthic invertebrates Platycephalidae Bartail flatheadPlatycephalus indicus38 ± 3.0 229 ± 7.740Benthic invertebrates & fishes
investigation revealed that harvested fishes by traps belong to different fish categories concerning size & shape, feeding behavior and natural habitats.
Concerning feeding behavior, the catch contains fishes belonging to herbivor- ous fishes such as Siganidae, fishes belonging to carnivorous fishes such as Serranidae and fishes belonging to omnivorous fishes such as Sparidae. Accord- ing to their natural habitats, there are demersal fishes such as Platycephalidae &
Mullidae and intermediate water column fishes such as Lethrinidae and Caran- gidae. It is obvious that the mean size of fishes harvested by small traps was smaller than fishes harvested by large traps and less than their Lm50.
Impacts of Traps
Traps are static bottom fishing gears anchored to the seabed and left to fish passively, the traps mostly baited by breads and occasionally by trash fishes, squids or chicken intestine to attract target species through one or more entranc- es into traps. Since the areas of seabed affected by each trap is likely to be insig- nificant compared with the widespread effects of mobile fishing gears. How- ever, the fishing effort may be significant if concentrated in relatively small areas with communities of long-lived fauna. Some studies made in northern Europe (Millner, 1985; Potter and Pawson, 1991 and Eno et al., 1996) indicated that the direct contact of static fishing gears with fauna may not be the primary cause of mortality and the frequency and intensity of physical contact is more likely to be important. Fish traps usually deployed around coral reef areas where a proliferation of coral growth makes handline fishing difficult. In the Arabian Gulf fisheries, the average life of a trap is estimated by the fishermen to be from two to three years, depending upon where the trap is habitually placed. In proportion to the actual number of traps lost, the fishermen stoutly maintain that their most serious natural enemy is other fishermen; this threat of stealing has had an inhibiting effect on the entire industry and is the reason behind several practices. These usually include the scraping, scouring and resus- pension of substratum and occur against a background of natural disturbance.
The direct effects of a given fishing method on infaunal and epifaunal commu- nities will tend to increase with depth and the stability of the substrate. In shel- tered areas where complex habitats develop at minimal depth, such as coral reefs, the direct effects of fishing may be marked and have profound effects on the ability of the habitat to sustain fish production. The abundance of many reef fishes is positively correlated with topographic complexity (Risk, 1972; Porter et al., 1977; Luckhurst and Luckhurst, 1978; Carpenter et al., 1981; Thresher, 1983; Kaufman and Ebersole, 1984; Patton et al., 1985; Roberts and Ormond, 1987; Grigg, 1994 and Jennings et al., 1995) and habitat complexity will also influence the rates at which larval fish recruit to the reef from the plankton (Jones, 1992 and Connell and Jones, 1991). The differences are greater when
large well-developed areas of reef compared with areas that have been fished destructively until little topographic complexity remains (Pauly et al., 1989).
Once it has been lowered traps to the bottom, no buoy used to mark the location of the trap, the owner who usually records the spot by his GPS apparatus for memorizing the position of each trap. When several hundred traps are owned by a fisherman, this system obviously becomes impractical: in such case, only the locations of key traps are remembered to help recover the additional traps that are placed about them in the same general area. Once a boat stationed over one of these key traps, finding the outlying traps usually presents no difficulty.
How-ever, if the key trap has been destroyed or removed, it sometimes becomes virtually impossible to locate them and the entire sequence may become tempo- rarily lost. The elaborate routine connected with hauling a series of traps to the surface is known as "running", before the fisherman can run a trap, his helper must station the boat directly over the spot by "planting a setting" pole or using robe connected with winch. The trap raises to the surface by inserting the tines of the hooking pole under the frame above the entrance and lifting with a rapid handover-hand motion. After the fishes have been removed, the fisherman hastens to inspect the trap to make certain that it is his own before proceeding any further with the cleaning operations. Cleaning of the trap have been accom- plished by passing an ordinary stiff bristle scrub brush over the slats and frame to reduce any flourishing marine growth. If left uncleaned, the traps not only deteriorate more rapidly but also do not seem to attract as many fishes.
Compared with the proportions of target species removed by mobile fishing gears, the number of organisms removed by traps is probably small. However, these fisheries tend to be highly localized leading to a concentration of lost gear within relatively small areas. Consequently, the proportion of local stocks removed can be significant (Kruse and Kimber, 1993). Furthermore, many of these species have a high individual value and hence represent a large economic loss to the local fishing industry. In order to reduce these losses for undersized specimens, escape panels now fitted to many traps used in North America and biodegradable materials are used to ameliorate losses (Guillory, 1993 and Polo- vina, 1994).
Some recommendations for the improvement of the fishery’s traps could be suggested. First, the fishing effect must be controlled for the marine fisheries as a whole, it should be reminded that overfishing is brought about not only by increased fishing effort but also by the employment of destructive gears and techniques by fishermen. Hence, the effective enforcement of the fishery laws, rules and regulations related to destructive gears must be pursued. In addition, small traps with small opening funnel and small mesh size have a passive effect on the reproductive cycle of many fish species, that they catch large number of
immature fishes. Therefore, it could be recommended to operate the large and medium traps only while the small traps should be forbidden.
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