Search Results (4)

Catalan’s SPP^N, a measure of solvent polarity/polarizability has been analysed in terms of molecular properties derived from computational chemistry. The results show that SPP^N correlates positively with the molecular dipole moment and quadrupolar amplitude and negatively with the molecular polarizability. These correlations are shared with Kamet and Taft’s π* and Reichardt and Dimroth’s E_T(30). Thus, one can associate the solvent polarity with non-specific interactions involving the permanent charges on solvent molecules. It is also noted that the opposite correlations, all three parameters increasing with increasing solvent polarity but decreasing with increasing solvent polarizability, creates an ambiguity in their use, for example, in linear free energy relationships. Full article

The European conger, Conger conger, is a benthic marine fish species with a geographical distribution extending through the northeastern Atlantic and the Mediterranean. Despite being extensively distributed and widely appreciated by Spanish consumers, studies regarding parasite presence in this fish are scarce. In the present work, a hundred and eight specimens from the Mediterranean coast of northeastern Spain (Catalan waters) were surveyed for the presence of nematode parasites. Several species were morphologically identified: third-stage larvae of Anisakis type I (sensu Berland, 1961) (n = 131), third-stage larvae of Anisakis type II (sensu Berland, 1961) (n = 18), third- and fourth-stage larvae and adults of Hysterothylacium spp. (n = 48), adults of Cucullanus sp. (n = 391), and adults of Cristitectus congeri (n = 69). Moreover, some fish and decapode species were also observed as part of the host’s diet, with the most detected preys being Micromesistius poutassou, Sardina pilchardus, Macropipus sp., and Goneplax rhomboides. This represents the first survey of nematode parasites infecting C. conger from the northeastern Spanish Mediterranean waters. Among the parasite species detected, the presence of Anisakis species should be highlighted as the ingestion of C. conger parasitized with these larvae could potentially lead to anisakiasis in consumers. Full article

The small pelagic European sardine presents high commercial and ecological values. Due to its cold-temperate water affinity, stocks are affected by global warming. Water temperature rise may change primary productivity patterns, negatively affecting fish condition and increasing parasite incidence. In this context, sardine health status was evaluated through the annual cycle on the Catalan Coast using thermal regimes comparison. Morphogravimetric parameters, sex and gonadal stages were assessed; infection by nematodes was characterised, and body condition was estimated by the Le Cren Factor and lipid content measured using a fish fat meter. Significant statistical differences were observed in spawning dynamics, body condition, and parasite infection between thermal regimes. Sardines from the colder north area had better condition and an earlier spawning, with lower parasite incidence (in terms of total prevalence, mean intensity and abundance) than those from the southern coast. Hysterothylacium spp. was the most abundant nematode, while Anisakis spp. prevalence was null in the two locations. Seasonal differences in nematode load were observed along the Catalan Coast, with lower prevalence during the summer and higher in winter-spring. Although previous studies have underestimated parasite influence on sardine health status, parasite abundance and sardine condition were negatively correlated. Seawater temperature and primary productivity are the proposed factors promoting differentiation in nematode infection and fish condition throughout the annual cycle and between locations. Full article

The European sardine, Sardina pilchardus (Walbaum, 1792), is a cold-temperate water species from the Clupeid family. This small pelagic has a key functional role in the marine ecosystem along its distributional range in the northeast of the Atlantic Ocean, the Sea of Marmara, the Black Sea and the Mediterranean Sea. Furthermore, sardine is one of the most important commercial fishery resources caught by the purse seine fleet in the Mediterranean Sea. There is reported a decline in annual sardine catches in the Northwestern Mediterranean Sea, as well as smaller mean total length and sexual maturation size of the individuals, mainly attributed to increased water temperature and overfishing, which have a negative impact on energetic body condition, growth and reproduction. However, little is known about the impact of parasitism on sardine health status. In this work we analyzed the incidence of parasites in sardines from the Catalan Coast of the Northwestern Iberian Peninsula, using two approaches: visual inspection by stereo microscope and the UV-press method, based on the autofluorescence of certain parasites, along a complete reproductive cycle. The main parasite found was the nematode Hysterothylacium sp., although other species were identified by visual inspection (i.e., Contracaecum sp., digenea trematodes). No Anisakis spp. were observed under either of the methodologies. Using the former method, we detected 35.3 % of individuals infected by, at least, one nematode parasite with a mean intensity of 1.68 %. With the UV-press technique, we quantified a prevalence of 16.5 %. In both cases, the Southern Catalan Coast presented a larger number of parasitized sardines, which was remarkably higher in spring. Combined methodologies are suggested to more precisely detect parasites, since visual inspection allows a more detailed study of the viscera, but UV-press also allows the study of parasites that may be present in the musculature. Furthermore, genetic validation should be performed in order to accurately determine the parasite species found. Full article