Length structure analysis of the Atlantic thread herring (Opisthonema oglinum) captured in the Santa Cruz Channel (Pernambuco, Brazil), using generalized additive models for location, scale and shape

The Atlantic thread herring (Opisthonema oglinum) is the most common sardine in Santa Cruz Channel landings, which is located on the Northern coast of Pernambuco state, in Brazil. The species spends part of its life cycle at sea and enters estuaries at strategic times. Its high exploitation and importance to the economy in the municipalities surrounding the channel led us to reflect on the need for investigations to promote sustainable fishing and a better understanding of its behavior in that place. In this study, the standard length of the specimens was estimated using generalized additive models for location, scale, and shape, and the factors that drive the length pattern along the estuary were discussed. It was identified the presence of larger individuals in the rainy season and greater concentration in the Center-South region of the channel. The smaller sardines were concentrated near the outflow of the Botafogo River, an area of ​​secondary channels with greater mangrove coverage. Few adults enter the channel and the vast majority of specimens captured were young. Thus, it would be pertinent to explore specimens that have at least reached sexual maturity, since the capture of young individuals can cause an imbalance of species sustainability.