Data source for RIMF through the Assessment of Marine Living Resource in Vietnam (ALMRV) project and data from the surveys conducted from 2001 to 2004 in the Gulf of Tonkin, Southeast and Southwest areas, such as 10 bottom trawl surveys, 8 net surveys and 9 hook surveys & line and longline are used in this report. The fisheries structure of Binh Thuan and Ba Ria - Vung Tau 3.1.1 The fisheries structure of Binh Thuan province. Only 542 fishing boats have engine capacity >90 hp and correspond to 10.5% of the total number of fishing boats in the entire province.
There are 1,962 boats with a capacity of >90 HP, representing about 37.66% of the total number of fishing boats of the entire province. Fishing Gear Group's fleet of fishing boats in Ba Ri - Vung Tau Province (as of 30 March 2004). Fishing gear specialized for catching sharks: The main fishing gear for catching sharks is the longline.
Due to its small size, fishing boats can operate offshore from March to June, the period of calm seas and also of the highest catch. Although the volume of sharks in one catch is not high (only the number of fishing boats and total fishery products per these two fishing gears is extremely high). The share of shark volume in relation to total fishery products was lowest with seining (0%), then with single trawl and team trawl (0.1%) and highest in the case with gillnet (1.53%).
As for the boats that catch sharks with a line, the level of quantity of sharks caught is very high and higher than other fisheries products ranging up to.
Survey No.4
Use and Trade of Shark .1 Use of shark
Trade of shark
At the market in Ho Chi Minh City, they sell dried shark meat, which can be processed into pieces soaked in spices. In the first quarter of January 2004 alone, one magnate bought 5 tons of skin and 50 kg of bone. The price of shark products: according to market surveys of 2 provinces, the prices of shark products are shown in Table 10.
Finished shark fins sold in shops next to Con Cha Port, Phan. Dried shark skin sold in shops at a shop next to Con Cha Port, Phan. Finished shark fins sold in shops at a shop next to Con Cha Port.
Finished Shark Fins Sold in shops at a shop near Con Cha's landing site, Phan.
Biological Analysis .1 Caught shark species
Biological analysis for surveys
Shark species composition (January) in Binh Thuan and Vung Tau Shark species Total sample (kg). Specimen species for bioassays from samples collected in Binh Thuan and Vung Tau (January). Carcharhinus sorrah: 301 individuals - Chiloscyllium plagiosum: 6 individuals - Carcharhinus falciformis: 1 individual - Atelomycteus marmoratus: 2 individuals - Sphyrna lewini: 2 individuals - Chiloscyllium griseum: 13 individuals - Heterodontus zebra: 1 individual.
For the purpose of assessing the development period of individuals of each species, the individuals of each species were divided by weight group for the species of many individuals, which are carcharhinus sorrah and chiloseyllium griseum. Average weight and length of the above species were calculated and shown in Tables 21 and 22. Average weight and length of Carcharhinus Sorrah quantity. The average weight of female fish in one group is higher than male fish - The average length of female fish in one group is greater than male fish Table 22.
The average weight of male fish in one group is higher than female fish – The average length of male fish in one group is greater than female fish. Carcharhinus sorrah (C¸ mËp miÖng réng): 12 individuals - Chiloscyllium plagiosum (C¸ nh¸m tróc v»n): 6 individuals - Atelomycterus marmoratus (C¸ nh¸m chÊm): 1 individual - Chiloscyllium griseum (C¸ nh ¸m chÊm): ¸m chã mµu tro): 2 individuals. As for the 8.2-10.7 kg individual, the female fish has a reproductive period and the male fish is in phase II development.
Shark species composition (July) in Binh Thuan and Vung Tau shark species Total sample (kg). In the shark survey in October and November 2004 in Binh Thuan and Ba Ria - Vung Tau, researchers made a biological study of only 63 individuals of 6 species. The biological survey was not conducted at Ba Ria - Vung Tau because the researchers could not see the sharks at the landing site due to the time of the middle of the lunar phase.
With reference to the above table of biological study on sharks made in the survey in October and November 2004 in Binh Thuan and Ba Ria - Vung Tau, 29 sharks of 4 species were analyzed. As for Carcharhinus sorrah (c¸ mËp miÖng réng) of less than 2 kg which includes both male and female individuals, their gonads are not clearly developed. Shark Species Composition (November) in Binh Thuan and Vung Tau Shark species Total sample (kg for 2. days) % of total sampled catch Do not fill Do not fill Do not fill.
Species Composition
K Heterodontidae Heterodontus zebra Zebra bull shark Cá Nhám húr S Sphyrnidae Sphyrna lewini Smurfhead hammerhead Cá Nhám búa. In the Gulf of Tonkin: 23 species of cartilaginous fish of 10 different families have been identified, of which 8 species were sharks (belonging to 5 families) and 15 species of rays (of the remaining 5 families). In the southeastern area: 24 species of cartilaginous fish of 12 different families have been identified: 11 species of sharks (of 7 families) and 13 species of rays of 5 remaining families.
In the southwestern area: 16 species of cartilaginous fish of 7 different families were found: 8 species of sharks (of 4 families) and 8 species of rays of 3 remaining families. In conclusion, the comparison of the species composition made for these waters at the same time showed that the highest number of cartilaginous fish as well as species of sharks can be found in the southeastern area. However, the water with the highest number of rays is in the Gulf of Tonkin.
Catch Per Unit of Efforts (CPUE) by Bottom Trawl 1. Shark
Rays
A comparison is made for 3 research areas, the CPUE of bottom trawled ray in the Gulf of Tonkin (Figure 33) is the highest (about 2.9 kg/h), while the catch of ray in the southeast and southwest areas with the same type of fishing gear is almost the same and much lower than the catch in the Gulf of Tonkin (about 1.7 and 1.75 kg/h). Ray CPUE by depth and season in bottom trawling in the Gulf of Tonkin area. CPUE ray by depths and seasons of bottom trawling in the Gulf of Tonkin.
CPUE of rays by depth and season of demersal trawling in the southeast area. Ray CPUE by depth and bottom trawl season in the southeast area. Ray CPUE by depth and season of bottom trawl fishing in the Southwest area.
Stingray CPUE by depths and bottom trawl fishing seasons in the South West Area.
Catch by Gillnet and Long line
In contrast, the lowest catch was encountered in the southwest monsoon of 2003, about 0.18 kg/km.
Percentage of Catch of Shark and Rays
ESTIMATION OF STANDING BIOMASS
The highest standing biomass of sharks is observed during the 2003 southwest monsoon and lowest during the 2004 southwest monsoon. The standing biomass of sharks in different monsoon seasons in the southeast region is shown in Table 35. In conclusion, the standing biomass of sharks in The Southeast area was estimated to be the highest compared to other parts of Vietnam.
