ALBERT

Description: SFA/R&D/061

Description: Published

Description: (1). During 2003 a total of 3,852 Metric Tonnes (MT) of fish was landed on Mahe, Praslin and La Digue by 405 fishing boats. 80.5% of the total catch was landed on Mahe alone. The total artisanal catch decreased by 1063 (MT) compared to 2002, whilst the number of boats operating increased by 31 over the same period (excluding sport fishing vessels). (2). The most important species groups landed (greater than 5% of the total catch) were carangues (33.6%), job (15.8%), bourgeois (9.1%), cordonier (6.6%), capitaine (6.1%), becune (6.0%), and maquereau doux (5.4%). Compared to 2002, there were notable increases in the relative importance of cordonier and bourgeois to the overall catch. (3). Peak landings occurred in November (463.7 MT) and the lowest catch was recorded in September (137.3 MT). The average monthly catch in 2003 was 321 (MT). (4). Slight seasonal variation in total catch was observed in 2003. The mean monthly catch during the months of May — October, inclusive; was 290.5 MT, compared to a mean montly catch of 318.1 MT during the months of December — March, inclusive. In contrast to the patterns observed in 2001 and 2002, the highest catches for carangues occurred in November rather than April. Catches of cordonnier continued to increase (254.7 MT) over the previous two years, with peak monthly catches coinciding with the peak spawning months for those species, namely October to December. (5). The percentage of the total artisanal catch taken by the small boat fishery (pirogues and outboards) was 28.3%, similar to the estimate obtained in 2002. Fishermen on foot landed 0.6% of the total artisanal catch, with octopus catches from this fishery totaling 21.3 MT in 2003. 5.4 MT of maquereau were landed by pirogues using beach seines. Carangues (22.6%) replaced maquereau doux (19.2%) as the most important species landed by vessels with outboards in 2003, other important groups in this fishery including cordonier (22.3%) and other trap fish (11.9%). In 2003, landings by the small boats and foot fishermen were divided equally between pelagic and semi-pelagic species (48.2%) and demersal/ reef species (51.8%). (6). Typical of previous years, the whaler handline fishery dominated artisanal fisheries catches, accounting for 63.4% of total landings in 2003. An average of 96 whalers operated each month during 2003, an increase of 5 vessels compared to 2002. Carangues made up 42.1% of the total whaler handline catch. Other important species in the catch were, in order of importance, job gris (22.1%), becune (8.3%) bourgeois (8.3%) and bonite (3.7%). For the second consecutive year, catches of bourgeois by the whaler handline fishery increased, by 22.2% over 2002. (7). A maximum of 16 schooners were in operation during 2002 and these vessels accounted for 6.8% of total landings. Bourgeois was again the most important species caught (36.9%), followed by the 'others' category (18.6%) and job gris (8.5%). The spanner crab Ranina ranina accounted for 5.8% of schooner landings. (8). Fish purchases from the artisanal fisheries by Oceana Fisheries Co. Ltd. were equivalent to 10.4% total landings (400.7 MT). Major species groups purchased were red snappers and bourgeois (219 MT), job (57.4 MT), groupers (30,6 MT), capitaine (23.2 MT), octopus (21.9 MT) and carangue (17 MT). (9). Fish purchases from foreign longline and purse seine vessels by Oceana Fisheries Co. Ltd. were 245.9 MT during 2002. Species purchased were all pelagic, of which bonito bait was the most common (112.8 MT), followed by yellowfin (40.3 MT), dorade (37.3 MT) and skipjack (14.1 MT). (10). Fish exports by Oceana Fisheries Co. Ltd. amounted to 201.1 MT, a decrease of around 25 MT compared to 2002. These exports were valued at SR 5.6 million (C.I.F). Compared to the previous year, the markets shifted in order of importance in 2003, with Mauritius constituting the major importer of Seychelles fish products (69.9 MT), followed by Reunion (55.6 MT), England (50.1 MT) and France (14.6 MT). Pelagic fishes (33.8%), bourgeois (29.5%) and job (15.8%) were the most important fish groups exported. (11). A comparison of data collected between 1991 and 2003 follows, The proportion of catch by boat type and number of boats operating shown in the following table does not include the research vessel (RJV L'Amitie) of the Seychelles Fishing Authority, which landed 3.1 MT of fish in 2003, contributing 0.1% to the total artisanal catch.

Description: Published

Description: (1). During 2002 an estimated total of 4915 tonnes of fish was landed on Mahe, Praslin and La Digue by 374 fishing boats. 83.1% of the total catch was landed on Mahe alone. The total catch increased by 625 tonnes compared to 2001, and the number of boats operating decreased by 3 over the same period. (2). The most important species groups landed (greater than 5% of the total catch) were carangues (41.5%), job (12.4%), capitaine (6.8%), becune (6.1%), maquereau doux (5.7%) and bourgeois (5.7%). (3). Peak landings occurred in October (576.5 MT) and the lowest catch was recorded in January (222.51 MT). The average catch per month was 409.6 tonnes. (4). Seasonal variation in catches of demersal species was less marked compared to previous years. The mean monthly catch during the SE Trades (May — October, inclusive) was 420.5 MT, compared to a mean monthly catch of 359.4 MT during the NW monsoon (December — March, inclusive). High catches were probably maintained during the period of May to October in 2002 due to the comparatively weak strength of the SE Trades in that year, as determined by lower than average wind speeds for most months in that period (Meteorological Office, pers. comm.). Identical to the pattern observed in 2001, the highest catches for carangues occurred in April. Catches of cordonnier in 2002 (203.0 MT) were more than double those recorded in 2001 (90.5), and were lowest during the period of March to June, inclusive. (5). In total, the small boat fishery accounted for 26.4% of fish landings during 2002. Compared to the total artisanal catch, the percentage catch by boat type for the small boat fishery was as follows: fishermen on foot — 0.6%; pirogues — 0.6%; outboards -25.2% and whalers with traps — 2.2%. Fishermen on foot mostly landed octopus (87.0%), although cordonnier catches by this category were also recorded in 2002 (12.6%). Due to changes in fisheries fieldworker coverage in 2002, landings of maquereau by pirogue were not recorded, with cordonnier (57.6%) and other trap fish (23.2%) dominating landings instead. The predominant species groups landed by outboards were, in order of importance, maquereau doux (22.6%), carangues (21.7%), other trap fish (13.9%) and cordonnier (13.6%). Whalers with traps landed mainly capitaine (61.3%), other trap fish (20.1%) and cordonnier (12.3%). In 2002, landings by the small boat fleet were once again approximately divided equally between pelagic (51.3%) and demersal/ reef species (47.4%). (6). The whaler handline fishery accounted for 67.9% of total landings. An average of 91 whalers operated each month during 2002, indicating an increase of 1 vessel operating when compared to 2001. Carangues made up 52.5% of the total whaler handline catch. Other important species in the catch were, in order of importance, job gris (16.4%), becune (8.4%) bourgeois (5.0%), bordemar (2.6%) and vara vara (2.2%). Catches of Bourgeois decreased by 28.8% in 2002 compared to the catch of 2001. (7). Purchases from the artisanal fisheries by Oceana Fisheries were equivalent to 10.3% of total landings (504.2 MT). Oceana Fisheries purchased all fish from the Port Victoria site. Major species groups purchased were red snappers and bourgeois (57.5%), job (12.7%), groupers (5.2%) and capitaine (5.9 %). (8). Fish purchases from foreign longline vessels were in the order of 152.3 MT of frozen fish (gutted and ungutted) during 2002. Species purchased were all pelagic, of which bonito bait was the most common (98.0 MT), followed by yellowfin (18.9 MT), dorade (12.6 MT) and skipjack (12.6 MT). (9). Fish exports by Oceana Fisheries amounted to 226.6 MT, 85.9% of which was fresh and 14.1% frozen. These exports were valued at SR 7.1 million (CIF). Major destinations for the fish were England (34.5%), Reunion (30.3%) and Mauritius (17.0%). Pelagic fish (41.5%), bourgeois (23.4%), and Job (19.2%). formed the most important fish groups exported. (10). A comparison of data collected between 1990 and 2002 follows. The proportion of catch by boat type and number of boats operating shown in the following table do not include the research vessels of the Seychelles Fishing Authority which landed 11.7 tonnes of fish in 2002, contributing 0.2% of the total catch.

Description: Published

Description: The status of an effort to increase the efficiency of calculating transient temperature fields in complex aerospace vehicle structures is described. The advantages and disadvantages of explicit and implicit algorithms are discussed. A promising set of implicit algorithms with variable time steps, known as the GEAR package is described. Four test problems, used for evaluating and comparing various algorithms, were selected and finite element models of the configurations are described. These problems include a space shuttle frame component, an insulated cylinder, a metallic panel for a thermal protection system, and a model of the space shuttle orbiter wing. Results generally indicate a preference for implicit oer explicit algorithms for solution of transient structural heat transfer problems when the governing equations are stiff.

Description: The SPAR thermal analyzer, a system of finite-element processors for performing steady-state and transient thermal analyses, is described. The processors communicate with each other through the SPAR random access data base. As each processor is executed, all pertinent source data is extracted from the data base and results are stored in the data base. Steady state temperature distributions are determined by a direct solution method for linear problems and a modified Newton-Raphson method for nonlinear problems. An explicit and several implicit methods are available for the solution of transient heat transfer problems. Finite element plotting capability is available for model checkout and verification.

Description: The use of the CYBER 203 vector computer for thermal analysis is investigated. Strengths of the CYBER 203 include the ability to perform, in vector mode using a 64 bit word, 50 million floating point operations per second (MFLOPS) for addition and subtraction, 25 MFLOPS for multiplication and 12.5 MFLOPS for division. The speed of scalar operation is comparable to that of a CDC 7600 and is some 2 to 3 times faster than Langley's CYBER 175s. The CYBER 203 has 1,048,576 64-bit words of real memory with an 80 nanosecond (nsec) access time. Memory is bit addressable and provides single error correction, double error detection (SECDED) capability. The virtual memory capability handles data in either 512 or 65,536 word pages. The machine has 256 registers with a 40 nsec access time. The weaknesses of the CYBER 203 include the amount of vector operation overhead and some data storage limitations. In vector operations there is a considerable amount of time before a single result is produced so that vector calculation speed is slower than scalar operation for short vectors.

Description: Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame tst article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described.