Surf zones are important for early life stages of several fish species for presenting characteristics such as high phytoplanktonic production, diverse food availability and shelter against predators. The action of waves in this environment provides nutrient cycling and increase the turbidity making surf zones ideal nursery environments for diverse species of fish, including clupeiforms. Clupeiform species have a great ecological and economic value for being abundant fish in tropical sandy beaches surf zones with significant fisheries importance. Studies about their feeding ecology and environment use are relevant, and one of the methods improving this knowledge is the application of ecomorphological analyses, which helps understanding species ecological interactions and their adaptations. In this context, the present study aimed to identify the ecomorphological relations and infer about the feeding ecology of eight sympatric clupeiform species in a Brazilian tropical sandy beach. Ten ecomorphological variables were analyzed of individuals belonging to the species Anchoa tricolor (Spix & Agassiz, 1829), Anchoa januaria (Steindachner, 1879), Anchovia clupeoides (Swainson, 1839), Anchoviella lepidentostole (Fowler, 1911), Lycengraulis grossidens (Spix & Agassiz, 1829), Chirocentrodon bleekerianus (Poey, 1867), Harengula clupeola (Cuvier, 1829) and Opisthonema oglinum (Lesueur, 1818), whose values were employed in a principal component analysis (PCA) with the two first axis explaining 58.92% of the total variance. A high morphological overlap between the species of Engraulidae was observed with the exception of A. clupeoides, which differed from the others for presenting higher values of the compression index and caudal peduncle compression index. The Clupeidae species differed from the other families due to higher values of relative height and relative head length which also showed differences between the species themselves, having H. clupeola presented the highest values of these variables. The representative of Pristigasteridae showed an intermediate overlap between the species of the other families because of its highly compressed body but with low scores of relative height, caudal peduncle relative length and mouth aspect ratio. The morphological differentiation between the families and even between species from the same family indicates niche divergences, showing that besides their phylogenetical proximity there are differences in their ecological interactions which possibly contribute to their coexistence.

Small pelagic fishes develop important role in human nutrition especially in emergent countries which are considered an affordable source of protein ensuring food security, and with its fishery being source of income for several populations around the world. Despite fish nutritional composition present several benefits for human health, prices are pointed as the main factor to choose seafood as components of diet, highlighting the relevance of the economic analysis of these items once disturbances in its prices might alter the feeding patterns of populations worldwide. This study aimed to analyze the Brazilian Sardine (Sardinella brasiliensis) prices dynamics in one of the main markets of northeastern Brazil, evaluate possible reasons for its peaks and use machine learning techniques to forecast its future prices. The dataset used was obtained in the Pernambuco Supply and Logistics Center (PSLC) website, which contains a historical series of sardine’s prices from 2013 to 2022. The dataset was divided in train and test sections, the train section modelled using the Fbprophet library and a long-short term memory neural network in order forecast the future prices, then the test dataset was used to evaluate the predictions based in the root mean square error, mean absolute error and mean absolute percentage error metrics. Both algorithms reached low error metrics in its forecasts, however LSTM predictions were significantly better presenting lower error metrics than Fbprophet, showing their usability in the economic context of marine sciences opening the door to further studies of the dynamics of food prices around the world.