Comer o ser comido: factores que determinan la condición nutricional de larvas de Engraulis anchoita de la población patagónica de la especie

RNA/DNA and derived condition indices for anchovy and hake larvae as relevant information for comprehensive fisheries management

“…Little information is available on the nutritional condition of the anchovy southern stock, so the results presented here are highly important. Somewhat lower RD values were observed than those previously reported in the study area (Diaz et al 2016, Do Souto et al 2019, and a large percentage of anchovy larvae were recorded below the critical value of the RD index in the zone external to the NPFS. The internal area of the NPFS showed a lower proportion of individuals under starvation and a higher incidence of individuals showing optimal growth.…”

“…Various studies have inferred the importance of the NPFS as a nursery area for the southern anchovy stock (Bakun and Parrish 1991, Diaz et al 2016, Do Souto et al 2018, with better feeding conditions for anchovy and hake larvae in the area associated with the NPFS Ramírez 1996, Temperoni et al 2014). Our results support this idea of better feeding conditions towards the NPFS.…”

“…It is evident that frontal systems play a fundamental role in the ecological processes of the ocean because they allow a high primary production, they are suitable areas for the reproduction and feeding of many nektonic species, they offer a suitable breeding environment for the feeding of the early stages of fish development, and they act as retention zones (Acha et al 2004). NPFS could also be an area with a high concentration of prey, predators and competitors of anchovy and hake eggs and larvae (Mianzan and Guerrero 2000, Álvarez-Colombo et al 2003, Diaz et al 2016, 2020.…”

Ontogeny versus environmental forcing off the Southwest Atlantic Ocean: Nutritional condition of Fuegian sprat (Sprattus fuegensis) early stages

“…fuegensis appear to present less variability in sRD values compared with other larval stages implying that the observed trend should not be overlooked. There is abundant evidence supporting the effect of food availability both in terms of quantity and quality over the nutritional condition of fish larvae (Diaz et al, 2016; Voss et al, 2006), being a predominant factor conditioning growth when the temperature range is narrow (Buckley, 1984). Nauplii, copepods, and cladocerans are main prey items for sprat early life stages, with an increasing selectivity for larger copepods with increasing length and with microplankton (i.e., diatoms, ciliates and other unicellular organisms) as predominant prey during the beginning of the spawning season (Arrhenius, 1996; Dickmann et al, 2007; Voss et al, 2003).…”

“…This scenario has been registered in the North Patagonian shelf, where higher sRD values of E . anchoita larvae were measured in a coastal frontal area (42–44°S) with strong water stratification compared with a less stratified one (Diaz et al, 2016). On the contrary, intense upwelling and mixing occur over the MPAN/BB, resulting in weak water stratification (Guerrero et al, 1999; Matano et al, 2019).…”