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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).
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.
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