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Two hundred and eighty-one anisakid larvae were found encapsulated in stomachs and mesenteries of 69 blackspot seabreams, Pagellus bogaraveo from Madeiran waters. Ninety-four larvae were identified as Anisakis simplex s.s., Anisakis pegreffii (Type I larvae), Anisakis simplex s.l. (Type II larvae) and Hysterothylacium sp. Prevalence of infection with anisakids increased with host length from 81.3% to a maximum of 96.3%. Mean intensity ranged from 3.5 (at length class 25 cm) to 4.8 (at length class 35 cm), with the majority of fish infected with only 1 or 2 parasites. A positive but not significant correlation was found between intensity and length (rₛ = 0.0419, p = 0.717). The high values of prevalence and low values of intensity may indicate that the anisakid larvae are dispersed within their hosts. No particular histopathological lesions were found associated with the presence of the nematodes, corroborated by a positive but not significant correlation that was found between intensity and condition factor (rₛ = 0.242, p = 0.035).
We propose to name as Lamellodiscus theroni sp. nov., the gill parasite of Diplodus puntazzo (Cetti) that was reported by Euzet (1984) as L. ergensi Euzet and Oliver, 1966 in Kerkennah Island (Tunisia). L. theroni sp. nov. was also found specific to D. puntazzo in Algiers Bay (Algeria) and in Gulf of Lion (France). The host specificity of various Lamellodiscus species on D. puntazzo is briefly discussed. Within Lamellodiscus, L. theroni belongs to the “ignoratus” group characterized by a “lyre” shaped male copulatory organ and to the “ergensi” subgroup, characterized by a complex morphology of the haptoral dorsal bars. L. theroni differs from the five other species of this subgroup (L. ergensi, L. kechemirae, L. tomentosus, L. sanfilippoi, L. baeri) by the morphology and the size of the haptoral dorsal bar. L. theroni, as well as, L. hilii, L. bidens, L. impervius, was only reported on the sparid Diplodus puntazzo. These parasite species are all considered as oioxenic.
Lamellodiscus crampus sp. nov. (Monogenea, Diplectanidae) is described from the gills of Dentex maroccanus (Valenciennes) collected from the Gulf of Gabès (Tunisia) in the oriental part of Mediterranean Sea. The new species belongs to the “ignoratus” group (sensu Oliver 1987) characterized by a lamellodisc with complete lamellae and a “lyre” shaped male copulatory organ, and the “ignoratus” sensu stricto subgroup, characterized by a haptor with simple lateral dorsal bars, as proposed by Amine and Euzet (2005). Lamellodiscus crampus can be easily distinguished from all the congeneric species of the subgroup “ignoratus” by the presence, in the “lyre” male copulatory organ, of five spines in the distal portion on the axial side of the paired piece.
new nematode species, Philometroides acanthopagri sp. nov. (Philometridae), is described from gravid and subgravid specimens found in the musculature near pectoral fins and in nasal cavity of the yellowfin seabream Acanthopagrus latus (Houttuyn) (Sparidae, Perciformes) from marine waters off the coast of southern Iraq. Based on light and scanning electron microscopical examination, the new species differs from its congeners in a combination of morphological and biometrical features. It is the first species of Philometroides reported from a sparid fish and the first representative of this genus recorded from fishes in the Arabian Gulf. A key to Philometroides species parasitizing marine and brackish-water fishes is provided.
Background. Our previous study demonstrated that sharpsnout seabream, Diplodus puntazzo (Walbaum, 1792), can be fed with up to 34.8% sunflower meal (SFM), with excellent results in growth parameters and feed efficiency. The aim of the current study was to test the replacement of fish meal with SFM in the diet formulation for sharpsnout seabream and to evaluate growth, nutritive parameters, amino acid retention, and body composition of the fish during the fattening period. Materials and methods. Sixteen baskets (300-L capacity), each with thirteen fish, were distributed in a recirculated saltwater system to allow four experimental diets containing 40% crude protein (CP) and 20% crude lipid (CL) with 0%, 11.7%, 23.5%, and 34.8% SFM partially replacing fish meal to be used in quadruplicate for this experiment. The fish were fed these diets ad libitum during the experiment, which lasted for 162 days. Growth, nutrition efficiency, biometrics, carcass composition, amino acid composition, and amino acid retention of the experimental fish were evaluated. Results. There were no statistical differences in the growth parameters among the treatments. However, fish fed a diet containing 34.8% SFM had the lowest feed intake (FI), lowest feed conversion ratio (FCR), and the highest protein efficiency ratio (PER). There were also no statistical differences in the biometric parameters although fish fed the diet containing 10% SFM had the lowest CP levels. Leucine was the only difference in the essential amino acid (EEA) profile with fish fed a diet containing 11.7% SFM having the lowest levels of leucine. Although there were fluctuations among the amino acid retentions, they were not statistically significant. Conclusion. SFM (up to 34.8%) can be included in the diets of sharpsnout seabream, thereby, replacing 27% of the fish meal without altering the fish growth.
Background. The influx of foreign fishing vessels in the Arabian Sea, during the mid 1990’s, has sparked some conflicts between artisanal and industrial fleets and raised concerns related to the resource management implications of fish stocks in the region. To address the lack of management data on the basic biology and stock assessment for targeted species, the Ministry of Fisheries Wealth in Oman initiated this study with a view to contributing towards the development of a management plan for the sustainable exploitation of the living resources of the sea in this region. Materials and methods. A database including biological parameters, length-frequency distributions and catches of king soldier bream, Argyrops spinifer (Forsskål, 1775), in Oman according to fleet (gear/technique) and region was compiled by monthly sampling in 2001 to 2002. In this study, length cohort and yield per recruit analyses were examined after simulating changes in fishing effort, in length at first capture and introducing a closed season for trawlers. Results. The results showed that: (i) the status of the stock is healthy, the average fishing mortality rate is moderate (0.1) and acts in general on the adult fraction of the stock. The fishing pattern differs, however, among fleets with some fleet components fishing, in part, for immature king soldier bream. (ii) An increase in total fishing effort would not lead to any long-term substantial increase of the catch (according the uncertainty of M value); however, the spawning stock biomass would decrease significantly. This measure affects negatively fleets that target the larger specimens. (iii) A moderate (±20%) modification of minimum length limit in catches would not affect, substantially, the sustainable yield and the spawning stock biomass. (iv) Any regulation of trawler fishing by closed season (i.e. restricted trawler activities during some seasons) would not have a significant effect on the long-term yield. Conclusion. The current pattern of exploitation and fishing effort acting on the A. spinifer stock are optimal and no changes to global fishing or length at first capture are recommended. Also, with the actual fishing effort of trawlers, no closed season is suggested. However, fleet components whose catches include some juvenile fraction should adopt more selective gear as used by the hand line fishery in the Al-Wusta region.
Two species of Lernanthropus de Blainville, 1822 parasitic on the sparid fish Pagrus pagrus L., 1758 and the sciaenid fish Umbrina canosai Berg, 1895, respectively, from the coastal zone of the State of Rio de Janeiro, Brazil, are redescribed and illustrated: L. caudatus Wilson, 1922, and L. leidyi Wilson, 1922. The male specimens of L. caudatus are described for the first time. There are new geographical and host records for these Lernanthropus species.
Background. The aim of this work was to study the growth of juvenile dentex fed on cooking-extruded diets,determine the level of substitution of fishmeal by soybean meal may be without affecting the growth in his species and its digestibility. Materials and Methods. The availability of defatted soybean meal as a substitute for fish meal was evaluated In juvenile (41 g on average) dentex by feeding diets containing 0%–60% soybean meal, for 97 days. Results. Survival at the end of the experiment was high (80%) except for the fish fed diets with 50% and 60% substitution. Growth, feed gain ratio, and protein efficiency ratio (PER) were slightly reduced at higher soybean meal levels. Fish fed diets containing 0% to 40% of soybean meal grew significantly more and FCR was lower than fish fed other diets. No differences were obtained for protein digestibility coefficients of experimental diets (20%, 30%, 40%, and 50% SBM). Conclusion. The results confirm the best protein level for optimum growth seems to be around 50% and 12% lipid level, and maximum soybean meal substitution of 40%.
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