Journal of King Abdulaziz University: Marine Sciences

Estimation of effected radon released from Ktebban River, north Basrah city, by using CR-39

2024-03-09T10:49:29+00:00

Abstract

In this work, closed can technique is uses to estimate the radon and radium content in solid samples, the estimation of the radon concentration was between 9.46±2.29Bq.m^-3 to 29.83±4.81Bq.m^-3, so that the effective radium variation from 0.001 Bq.kg^-1 to 0.004571 Bq.kg^-1 since it was responsible for radon emanation in the air. These values considered as with the acceptable values worldwide with neighbors countries. The flux and exhalation per unit area and per unit mass arranged between 0.13Bq. m^-2h^-1 to 0.54Bq.m^-2h^-1and 0.003Bq.m^-2h^-1 to 0.015Bq.m^-2h^-1 respectively. These values are lower than the reported worldwide limit which indicates. It is safe use sediments as building materials or other uses.

Prevalence and PCR detection of Salmonella spp. and Escherichia coli in water used during live transportation of climbing perch (Anabas testudineus) in Bangladesh

2023-11-29T10:27:03+00:00

This research investigated the incidence of two foodborne pathogens,
Salmonella spp. and Escherichia coli in water used during live transportation of climbing perch
(Anabas testudineus). Assessments were conducted in three commercially important fish supply channels of Bangladesh, starting from an important production area, Muktagacha, Mymensingh to Dhaka (supply channel 1), Sylhet (supply channel 2), and Rajshahi (supply channel 3). Water samples were collected from 0 hours (at the time of loading) to reaching at the final destination (unloading points/ retail markets) at every 2 hours interval during transportation. To assess the prevalence of Salmonella spp. and E. coli, Salmonella-Shigella (SS) agar and Eosin methylene blue (EMB) agar plate counts were taken into consideration. For confirmation and PCR detection, a total of 52 isolates were obtained from those cultured plates based on the colony characteristics. The finding showed a gradual increase in SS- and EMB agar plate counts in all the supply channels. Out of the 52 isolates, 10 (19%) were detected as positive for Salmonella spp., while 38 (73%) as positive for E. coli. It was assessed that the pond waters of the cultured areas might be the primary sources of contamination of these two foodborne pathogens.

Diversity and Abundance of the Commercial Fish at Some Coastal Coral Reef Bays in Marsa Alam, Red Sea, Egypt

2023-09-15T08:44:08+00:00

This work aimed to study the structure of the commercial fish communities at six coastal coral reef bays around Marsa Alam city on the southern coast of the Egyptian Red Sea. Fish communities were counted in Marsa Saifen, Marsa Shoni2, Marsa Shoni4, Marsa Fujiri, Marsa Nakari and Marsa Hamata using underwater visual census technique (UVC).

A total of 2458 fish belonging to 16 families and 44 species of commercial fish were found. Five families (Scaridae, Serranidae, Mullidae, Lutjanidae and Lethrinidae) contained 27 species (61.4% of the total number of species). Four families (Mullidae, Siganidae, Scaridae and Lutjanidae) were the most abundant and they formed about 91.3% of the total number of recorded individuals. Mullidae was the most abundant constituting about 63.5% of the fish community). The most abundant species was Mulloidichthys flavolineatus, of the family Mullidae with 1390 individuals forming 56.5%, followed by Siganus rivulatus of the family Siganidae (251, 10.2%). The highest abundance of fish was recorded in Marsa Saifen (609 individuals) and the lowest abundance was recorded at Hamata (271 individuals). The highest number of species (23 species) was observed in Marsa Fujiri, whereas the lowest number of species (17 species (was recorded in Hamata.

This study concluded that knowledge of the ecology of marine fish communities in the Red Sea is sparse and hence quantitative ecological studies are needed. Action plans and research programs must be developed to reduce early stages bycatch and initiate fisheries management strategies for commercially exploited species.

Stock Study of Bali Sardinella Fisheries at Pengambengan Nusantara Fishing Port, Bali

2023-12-05T13:31:13+00:00

Stock assessment is one of the efforts to see the impact and influence of fishing activities on fish stocks and populations. One of the fishery resources that has important economic value in Indonesia is Bali sardinella fisheries. The high production of Bali sardinella fisheries at the Pengambengan Nusantara Fishing Port (NFP) encourages an increase in intensity and catch effort, so it is feared that overexploitation may occur. This study uses primary data and secondary data from Pengambengan NFP, to analyze the level of effort, catch, and economic rent of Bali sardinella fisheries under MSY, MEY, and OA conditions. The result of the linear equation CPUE = -0.00008f + 3.1053, if the capture effort is increased it will reduce the CPUE value, and vice versa. The regression results of the Schaefer Model obtained E_MSY results of 4,691 trips per year, MSY of 17,639 tons per year, and TAC of 14,111 tons per year. The results of the bioeconomic model prediction obtained E_MEY and MEY values, namely 4,554 trips per year and 17,624 tons per year.

Growth, Feed, and Food Habits of Saurida tumbil (Bloch, 1795) in Jizan fisheries, Saudi Arabia

2023-11-12T09:54:03+00:00

The current study provides the latest scientific evaluation on growth and feeding habits of Saurida tumbil in Jizan fisheries. Monthly samples were collected from September 2021 to April 2022, with a total of 343 individuals. Fish scales were used for age determination and back-calculation of fish lengths at ages to estimate growth rates and von Bertalanffy growth parameters. Several food and feeding analyses were estimated to describe the feeding habits of this species. Results showed that Saurida tumbil is categorized as carnivorous fish. Terapon (Terapon sp.) and anchovy (Encrasicholina sp.) were observed mostly in the stomach followed by sardinella (Sardinella sp.), squid (Loliginidae), and berber ponyfish (Leiognathus berbis). Vacuity index () analysis showed that Saurida tumbil is categorised as middle alimentative regularly regarding the feeding habit according to stomach fullness. The value of GaSI was 3.08 in average. The total Length – gutted weight relationship results showed that Saurida tumbil is isometric in dimensional growth and can be described based on the power function: W_gutted = 0.0067 TL^3.014. The average back-calculated lengths at age were 18.5, 27.0, 32.4 and 37.4 cm corresponding to the first, second, third and fourth year of life, respectively. The von Bertalanffy growth parameters were found to be: the asymptotic length L_ꝏ = 50.38 cm, growth constant K= 0.30 per year. The hypothetical age at zero length t₀ = -0.48 year. The growth in length performance index (Ф') was 2.88.

Age and Growth of the Silver Grunt Pomadasys argenteus (Forsskal, 1775) in Jizan Fisheries, Saudi Arabia

2024-04-11T16:04:20+00:00

The silver grunt Pomadasys argenteus is one of the commercial fish species in the family Haemulidae widely distributed in the Indo-West Pacific (from Red Sea to Fiji). The age of this species was determined using scales. The back-calculated lengths-at-ages were estimated using the body proportional hypothesis (BPH) based on the relation between the body length and scale measurements. The relationship between the scale radius (S) and total length (L) could be described by the linear form: L = 4.632 S - 4.813 (R² = 0.93) for males, L = 4.37 S - 2.761 (R² = 0.94) for females, and L = 4.39 S - 3.28 (R² = 0.95) for pooled sexes. Seven age groups were determined for females (I⁺ to VII⁺), and five groups for males (I⁺ to V⁺). Growth parameters were estimated from the growth rates and found to be L_¥ (asymptotic length) = 52.33 cm, K (growth coefficient) = 0.197 yr^-1, and t_o(supposed age at zero length) = -0.74 yr for males; L_¥ = 57.39 cm, K = 0.174 yr^-1, and t_o= -0.82 yr for females; and L_¥ = 56.07 cm, K = 0.181 yr^-1, and t_o= -0.79 yr for pooled sexes. The length-weight relationship was described by the nonlinear power equation: W = 0.0130 L^3.014 (R² = 0.99) for males, W = 0.0146 L^2.98 (R² = 0.99) for females, and W = 0.0138 L^3.00 (R² = 0.99) for pooled sexes. The growth of this species is isometric where the regression slope for both sexes does not differ significantly from the value ' 3 ' of the isometric growth. The life span (maximum age) was estimated to be 16.4 yr for females, 14.5 yr for males, and 15.8 yr for combined sexes, indicating that the silver grunt in Jizan fisheries is a moderate sized fish species (between 10 to 20 yrs.).