Otoliths reading and length frequency distribution were used for age determination and growth estimation of Sardinella aurita (round sardinella) stock of Southern Atlantic coast of Morocco. Both otoliths' method for age determination and Bhattacharya’s method for length frequency analysis showed five age groups. The growth performance index revealed that there is significant accordance among method of length frequency distribution and otoliths reading for stock assessment studies of Sardinella aurita stock in the south of Morocco. The microscopic observation of female gonads using histology method was investigated for the first time in our study area and confirms the presence of five principal stages of ovary of sardinella aurita: immature, maturing virgin and recovering spent, mature (or pre-spawning phase), spawning, post-spawning or spent. In addition, our results of the fecundity showed that the mean relative fecundity obtained is estimated at 193 ± 98 oocytes/g which is lower compared to those obtained in other areas in the Atlantic coast.
Agroecosystems are becoming more developed in Morocco, which requires conducting research about their importance to indigenous avifauna. We studied the influence of seasonality and parcel characteristics, including habitat type and anthropogenic pressures on bird diversity in vineyards. Our findings show that bird diversity varies by habitat type with heterogeneous parcels being more diverse than homogeneous parcels; in addition to that, bird diversity was higher in edge habitat, olive and uncultivated land while it was lower in vine habitat, whereas the cereal was the poorest habitat in the vineyards. Our results revealed that avian diversity changes with the seasons, being higher in winter, autumn and spring than in the summer. Evaluation of anthropogenic pressures indicates that avifauna diversity was negatively associated with the distance to the nearest building and the nearest edge, but positively associated with the distance to the nearest water source. Our research identifies potentially important variables influencing bird diversity in these agricultural ecosystems, which can help us to understand more clearly the ecological needs of birds of this habitat.As a result, we make some recommendations to help preserve bird diversity and improve their survival, including securing and protecting edge habitat, boosting habitat diversity and contributing to the overall effort to reduce climate change impacts, all of which will not be possible without the cooperation of landowners, farmers, managers and researchers.
The biological interactions between species are not limited only to trophic relationships; parasitism and diseases also occur. However, predator-prey relationships have a dominant role. In fact, natural mortality can vary considerably with predation, famine, and disease, but predation seems to be the dominant factor (Daan, 1989). Studies on diet composition are crucial in community ecology considering that the use of resources by organisms has a major influence among population interactions within a community (Mequilla and Campos, 2007). Analysis of stomach contents could provide helpful information concerning the position of the fishes in the food web of their environment and estimation of trophic levels (Pauly and Christensen, 2000; Post et al., 2000). In addition, the quality and quantity of food are among primordial factors that ARTICLE INFO
A fragment of 680 bp of mitochondrial cytochrome b locus of European anchovies, Engraulis encrasicolus, was sequenced for 138 individuals collected from three Moroccan Atlantic areas and from Moroccan Alboran Sea. These samples were surveyed for diversity and differentiation with a range of summary statistics. The results showed that the most dominant clade in Moroccan anchovy is Clade A with a percentage ranging from 89% in Alboran Sea to 91% - 95 % in the Moroccan Atlantic coast. Overall, there was a significant genetic differentiation among the 4 Moroccan anchovy zones (Φst = 0.01283; p=0.03910). Pairwise Φst among populations and multidimensional scaling revealed a high homogeneity among Atlantic populations but some heterogeneity between Alboran population and Atlantic populations, mainly between the populations from Central Atlantic of Morocco with a significant difference.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.