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Background. The deep-water longline fishery of the blackspot seabream, Pagellus bogaraveo, is an economically important fishery in the Strait of Gibraltar, which is a very complex transition ecosystem between the Mediterranean Sea and the Atlantic Ocean with an extreme spatial and temporal variability. This paper presents a series of morphometric relations for the four most important species in this fishery. Some ecological considerations about the results are also discussed. Materials and Methods. The data were collected during a gear selectivity study, using different sizes of hooks baited with sardine. Relations for weight–length, length–length, and mouth dimensions for blackspot seabream, Pagellus bogaraveo (Brünnich, 1768); Atlantic pomfret, Brama brama (Bonnaterre, 1788); blackbelly rosefish, Helicolenus dactylopterus (Delaroche, 1809); and Mediterranean horse mackerel, Trachurus mediterraneus (Steindachner, 1868) were estimated and compared with the ones reported for the same species from other areas. Results. The sample size varied from 89 for T. mediterraneus to 2180 for P. bogaraveo. The fitted L–W relations explained more than 81% of the variance. For P. bogaraveo and T. mediterraneus, the estimated allometric coefficient was higher than those reported for other areas, showing a faster increase in weight, in contrast to H. dactylopterus and B. brama that showed a slower increase in weight. Moreover, linear and highly significant relations between mouth size and fish length were found for P. bogaraveo, H. dactylopterus, and T. mediterraneus. Conclusion. In this study, the first record for total length–standard length relation for H. dactylopterus is reported based on real measurements. There has been no previous studies on the relation between the different mouth size dimensions for the studied species as well as for mouth size and body length relations for P. bogaraveo and H. dactylopterus. The difference between estimated and reported coefficients might be attributed to different environmental adaptations and to the size ranges used due to the gear-size selectivity.
Fifteen species of digeneans are reported from the waters off the islands of the Outer Hebrides, off north-western Scotland. Trifoliovarium allocytti comb. nov. from Neocyttus helgae is described, figured, and reported for the first time in the northern hemisphere. Brachyenteron helicoleni sp. nov. from Helicolenus dactylopterus is described and considered distinct from other species in the genital pore being at the level of the pharynx, the relatively narrow caeca, the vitellarium being mainly at the level of the ventral sucker and the anterior hindbody, the posteriorly situated, oblique testes, the small amount of post-testicular uterus, the small, delicate cirrus-sac and the large eggs. Derogenes varicus and Lepidapedon arlenae are reported from Caelorhinchus labiatus and Paralepidapedon williamsi is reported from Cottunculus thomsoni for the first time. Steringovermes notacanthi and Prodistomum priedei are reported from off Scotland for the first time. The reports of Derogenes varicus at 1,800 m depth and Zoogonoides viviparus at 1,000 m are deeper records than have previously been published.
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