Time filter

Source Type

Anderson W.D.,College of Charleston | Chesalin M.V.,Fisheries Research Center Salalah | Jawad L.A.,Flat Bush | Al Shajibi S.R.,Fisheries Research Center Salalah
Zootaxa | Year: 2015

Symphysanodon andersoni was described in 1974 from a single specimen collected southwest of Socotra Island, near the entrance to the Gulf of Aden. A more recent report (2003) of its capture in the Gulf of Kutch, Arabian Sea, was based on a misidentification. The second known specimen of the Bucktoothed Slopefish, S. andersoni, (at 204 mm SL the largest known specimen of the genus Symphysanodon) was collected off the south coast of Oman, Arabian Sea, in April 2014. Symphysanodon andersoni is distinguishable from its congeners by number of tubed scales in the lateral line, 60 to 65 versus 42 to 59 in the other species of the genus. In view of the fact that S. andersoni is poorly known, we redescribe it based on the holotype and the new specimen collected off Oman and provide the first color photograph of the species. Copyright © 2015 Magnolia Press.

De Waal S.,Fisheries Research Center Salalah | Khoom S.,Fisheries Research Center Salalah | Al-Ghassani S.,Fisheries Research Center Salalah
Regional Studies in Marine Science | Year: 2016

An experimental tag and release/recapture experiment with juvenile H. mariae in three areas, Hassila, Haat and Raha, along the Dhofar coast of Oman demonstrated that the growth rates of H. mariae are driven by season and temperature. The winter NE monsoon and the summer SW monsoon have a significant effect on the monthly incremental growth of juvenile abalone (30-63 mm shell length, p<0.001). The peak average growth rates, up to 7.4 (SD ± 2.5) mm and 8.4 (SD ± 2.5) mm per month, occurred in October and September, respectively, with minimal growth of <1 mm occurring from March to May. The growth increases coincided with the blooming of Ulva sp. when the temperatures decreased and upwelling occurred. Growth also peaked when the kelp species Sargassum and Sargopsis were abundant. Complete growth inhibition occurred during April and May when very little algal biomass is available. The peak summer growth rates were approximately 3 times the lowest winter growth rates. A close relationship was identified between the chlorophyll-a levels and abalone growth. Increases in marine productivity are reflected in both the chlorophyll-a levels and the seasonal algal diversity, and the abundance is likely the most dominant driver of increased abalone growth along the Dhofar coast. © 2015 Elsevier B.V. All rights reserved.

Balkhair M.A.,Fisheries Research Center Salalah | Al-Mushikhi A.R.,Fisheries Research Center Salalah | Chesalin M.V.,Fisheries Research Center Salalah
Journal of Shellfish Research | Year: 2013

Hatched larvae, juveniles, and adults of the Omani abalone Haliotis mariae were cultivated in land-based tanks with filtered running seawater during 3 experiments: (1) from January 2001 to December 2005, (2) from January 2006 to November 2009, and (3) from January 2009 to December 2011. Larvae and early juveniles were fed daily with diatoms, whereas late juveniles and adults were fed with artificial food and the green algae Ulva fasciata. Shell length and total wet weight from 40-80 randomly selected specimens in various experiments were measured monthly, and sex and gonad maturity stage were defined visually. The water parameters in tanks reflected the ambient condition of the Arabian Sea. The growth pattern of the abalone was very similar in the 3 experimental trials. Larvae and early juveniles have very fast growth rates, reaching an average 53-56 mm and 19-25 g after 1 y. Better results were obtained in the second and third experiments, when at the end of 2 y of rearing, abalone mean length was 67-72 mm and the weight was 46-54 g. At the age 3 y, abalone attained a mean length of 83-85 mm and a weight of 89-93 g. After 6 y, the abalone from the first experiment (2001 to 2005) showed, on average, 88.5 mm and 110.9 g. The length increments were the highest during the first year of the culture, whereas weight increments reached maximum values during the third (second and third trials) and fourth year (first trial) of rearing. After 4 y, abalone growth increments in weight decreased significantly. Males generally but not always have larger increments in length and weight when compared with females. During cultivation, a decrease in abalone weight was sometimes observed that, in most cases, coincided with decrease in water temperature during the southwest monsoon period (June to September). Some abalone sexually matured in tanks after 1 y, and mature males and females occurred almost year-round, with peaks in April to May and November to December. The length at first maturity was found to be 65.2 mm for males and 67.1 mm for females. Growth parameters for a von Bertalanffy function were calculated using data from different experiments. The growth rate coefficient in the first experiment was lower (K = 0.65), but in third experiment it appeared higher (K = 0.80) than in natural conditions from data other authors calculated based on length-frequency distribution analysis, which indicates faster growth rates of abalone in tanks when compared with those in the wild. Results of the trials showed that it is feasible to produce Omani abalone in land-based farms from eggs to commercial size during a 3 4-y cycle.

Al-Shajibi S.R.,Fisheries Research Center Salalah | Chesalin M.V.,Fisheries Research Center Salalah | Al-Shagaa G.A.,Fisheries Research Center Salalah
Pakistan Journal of Zoology | Year: 2014

The first records of the bluntnose sixgill shark Hexanchus grisues and the bramble shark Echinorhinus brucus from southern Oman are reported. Descriptions, illustrations and morphometric data are presented. This represents the first record of H. griseus from Oman and extends its northernmost distribution in the Indian Ocean. © Copyright 2014 Zoological Society of Pakistan.

Waal S.D.,Fisheries Research Center Salalah | Balkhair M.,Fisheries Research Center Salalah | Al-Mashikhi A.,Fisheries Research Center Salalah | Khoom S.,Fisheries Research Center Salalah
Journal of Shellfish Research | Year: 2013

Restocking and potential stock enhancement of natural abalone stocks by seeding hatchery-reared juvenile abalone into suitable habitat is currently being investigated or implemented in a number of countries, including Japan, Australia, New Zealand, Mexico, and South Africa. A series of experiments has been conducted to investigate the feasibility and development of the technology required to do this in the Sultanate of Oman. Wild seed were collected between Mirbat and Ras Atian on the Dhofar coast and kept in a hatchery for 7 wk. Qualitative and observational data were used to develop seeding site selection criteria and a seeding density of 10 juveniles/m2. The juveniles were relocated and seeded in 18 different sites spread over a distance of 72 km. Sites selected with an abundance of boulders with a diameter of less than 50 cm yielded the highest recovery rates. Different categories of habitat availability and selection by seeded juveniles for specific habitat categories varied significantly among sites, which was reflected in the range of recovery rates. Boulder habitats less than 50 cm in diameter supported the most recovered juveniles (P = 0.002 and P = 0.005). Survival rates over a period of 30, 60, and 90 days ranged from 0%-80% and proved highly site specific (P = 0.04). A positive correlation was found between average seed size and increased recovery rates (P = 0.015, R= 0.25). Dispersal was limited in sites with high recovery rates. Site selection was shown to be vital. A simple seeding mechanism comprising a PVC tube proves successful as an alternative to seeding by hand.

Discover hidden collaborations