Distribuição espaço-temporal da fauna ictioplanctônica e de Chaetognatha e sua interação no litoral norte de Pernambuco

Abstract

The success of the early stages of life in fish influence recruitment and determines the structure of adult populations. In the larva period, these individuals are more vulnerable to predation and other factors that affect their survival and/or mortality. Chaetognathas are described as voracious predators and can feed on fish larvae, thus affecting the distribution and success of ichthyoplankton. In this context, the study aimed to analyze the spatial distribution of ichthyoplankton in the Jaguaribe River estuary and Jaguaribe beach, correlating with the occurrence of Chaetognatha. The collections were carried out in August, September, October and December 2017 in three points, these were distributed at the mouth of the Jaguaribe River, bursting Jaguaribe beach and corral. The collected individuals were fixed in situ in 4% saline formaldehyde and later screened in laboratory and stored in ethanol 70%. 88 larvae were collected, identified in three orders and six families, including: Achiridae, Engraulidae, Carangidae, Clupeidae, Gerreidae and Gobiidae. The most abundant family was Engraulidae, being present in all months and points sampled. The surf zone was the site with the highest abundance of larvae. 574 Chaetognathas were collected and identified in one order, two families and three species. These were present in all sampled points, however, they presented greater abundance in the corral region. A total of 5305 eggs were collected, of these 4161, they were eggs of Engraulidae. The month of September presented the highest abundance of eggs, with 78.4% of the total collected. When comparing the distribution of ichthyoplankton and Chaetognathas, an overlap was observed in the occurrence of these. The spatial distribution of ichthyoplankton is highly influenced by the occurrence of Chaetognathas, since these are large predators. With a decline in the abundance of Chaetognathas there is an increase in ichthyoplankton, proving the existence of an inversely proportional relationship.