Population parameters and the relationships between environmental factors and abundance of the Acetes americanus shrimp (Dendrobranchiata: Sergestidae) near a coastal upwelling region of Brazil

Abstract

The population dynamics of Acetes americanus was investigated, focusing on the sex ratio, individual growth, longevity, recruitment and relationship between abundance and environmental factors in the region of Macaé, strongly influenced by coastal upwelling. Otter trawl net samplings were performed from July 2010 to June 2011 at two points (5 m and 15 m). Nearly 19,500 specimens, predominantly females (77.15%), were captured. Their sizes, larger than that of males, indicated sexual dimorphism. Shrimps at lower latitudes present larger sizes and longer longevity than those from higher latitudes. This difference is probably due to low temperatures and high primary productivity. Though no statistical correlation was found between abundance and environmental factors, the species was more abundant in temperatures closer to 20.0º C and in months with high chlorophyll-a levels. Due to the peculiar characteristics of this region, A. americanusshowed greater differences in size and longevity than individuals sampled in other studies undertaken in the continental shelf of Southeast Brazil.

Factors affecting the seasonal variability of planktonic shrimps (Dendrobranchiata) along an estuary–ocean gradient on the Amazon continental shelf

“…distribution was primarily associated with higher temperatures and chlorophyll-a. Acetes americanus is known to have higher abundance in the months with high chlorophyll-a concentration (Santos et al, 2015) and it occurs in shallower sites with high temperatures and lower salinity values (Simões et al, 2013b); these patterns are similar to those found for Acetes spp. on ACS.…”

“…is well known; however, this was not evident on the ACS. Overall, recruitment is continuous throughout the year in tropical and subtropical regions, with spawning peaks occurring during hotter seasons (Xiao & Greenwood, 1993;Simões et al, 2013aSimões et al, , 2013bSantos et al, 2015). Acetes spp.…”

The ecological mechanisms of Acetes blooms as a threat to the security of cooling systems in coastal nuclear power plants

“…The sexual maturity index of A. indicus fluctuated annually, with the highest value occurring from June to August (Amin et al, 2009). A study of the population dynamics of Acetes americanus in the coastal upwelling area in Brazil found that the body lengths of females were significantly longer than those of males, and showed a substantial predominance (77%) in female abundance (Santos et al, 2015). Compared with high latitude regions, individuals (A. americanus) in low latitudes have significantly longer body lengths and lifespans (Santos et al, 2015).…”

“…A study of the population dynamics of Acetes americanus in the coastal upwelling area in Brazil found that the body lengths of females were significantly longer than those of males, and showed a substantial predominance (77%) in female abundance (Santos et al, 2015). Compared with high latitude regions, individuals (A. americanus) in low latitudes have significantly longer body lengths and lifespans (Santos et al, 2015). In a study of the reproductive biology of A. chinensis on the western coast of the Korean Peninsula, mature female individuals appeared at the beginning of April and reached their maximum abundance in July, and there were no mature females after September (Oh & Jeong, 2003).…”

Growth, age at sexual maturity, longevity and natural mortality of Alpheus brasileiro (Caridea: Alpheidae) from the south-eastern coast of Brazil

“…Through this model it is possible to estimate the maximum size that the individuals can reach, and thus, their longevity. Bertalanffy's model is considered the best one to study age in crustaceans (Davanso et al, 2013;Santos et al, 2015;Pescinelli et al, 2018b).…”