Life history traits of the invasive estuarine shrimp <i>Palaemon macrodactylus</i> (Caridea: Palaemonidae) in a marine environment (Mar del Plata, Argentina)

Abstract

SUMMARY: The invasive oriental shrimp Palaemon macrodactylus has been extensively recorded around the world, mainly in estuarine zones. In this study, the life history of this species was studied in Mar del Plata harbour (Argentina), a fully marine area where a stable and dense population has been established. Growth, sex proportion, morphological relationships, size at maturity and reproductive cycle were analysed between March 2007 and March 2009. A total of 9 and 7 modal classes (M1-M9) were detected in the size frequency distributions of females and males, respectively. The modes of both sexes were the same until M4 but from M5 to M7 females were larger than males. The life span was about one year with a clear seasonal growth. Recruitment and reproductive periods were recorded from December to March and October to March, respectively. The total sex ratio was biased to females. Nevertheless, a clear predominance of males was observed in classes smaller than 5.25 mm carapace length (CL). Females reached maturity at a larger size in spring to early summer (October-January) than in late summer (February-March); the estimated sizes for 50% sexual maturity were 6.79 mm and 5.91 mm CL, respectively. The results showed great differences from a presumably native estuarine population (Japan), such as shorter life span, smaller maximum size and smaller size at maturity.Keywords: life history, growth, intraspecific variability, invasive species, Caridea, reproduction. RESUMEN: CaraCterístiCas del CiClo vital del Camarón estuarino invasor Palaemon macrodactylus (Caridea: Palaemonidae) en un ambiente marino (mar del Plata, argentina). -El camarón oriental invasor Palaemon macrodactylus ha sido ampliamente documentado, principalmente en estuarios, alrededor del mundo. En este trabajo el ciclo de vida fue estudiado en el Puerto de Mar del Plata (Argentina), donde se registró una población estable y abundante en un ambiente netamente marino. Entre marzo de 2007 y marzo de 2009 se estudiaron: el crecimiento, la proporción de sexos, relaciones morfológicas, la talla de madurez y el ciclo reproductivo. A partir de las distribuciones de frecuencia de tallas se detectó un total de 7 y 9 clases modales (M1-M9) para machos y hembras respectivamente. Las modas de ambos sexos fueron iguales hasta la M4, mientras que en las M5-M7, las hembras fueron mayores. El tiempo de vida estimado fue de un año, con un crecimiento claramente estacional. El reclutamiento y el período reproductivo fueron registrados entre diciembre y marzo y entre octubre y marzo respectivamente. La relación de sexos fue sesgada hacia las hembras. Sin embargo, en las tallas menores a 5.25 mm de LC los machos fueron mayoría. Las hembras alcanzaron la madurez a una talla mayor en primavera/ inicio del verano (octubre-enero) que en el verano tardío (febrero-marzo). La talla del 50% de madurez estimada para cada período fue 6.79 mm y 5.91 mm de LC respectivamente. Los resultados mostraron grandes diferencias con una población estuarial presumiblemente del sitio de orige...

Effects of the upwelling system on the assessment of reproductive parameters of the caridean shrimp Nematopalaemonschmitti (Holthuis, 1950) in the Western Atlantic

“…The potential explanations for the proportion of females higher than males include differential growth rates and mortality between sex, longevity, migration, and preference for different habitats (Berglund, 1981;Wenner, 1972), and this may also be a result of a sampling trawl due to the smaller male body size. A similar female-biased sex ratio was observed in palaemonid shrimp Palaemon macrodactylus Rathbun 1902, which reported deviation by predation by females on males observed in laboratory cultures (differential mortality) (Vázquez et al, 2012). In addition, Pianka (1983) proposed that in populations where the female copulates with more than one partner, the tendency of the sex ratio favors the increase in the number of females.…”

Behaviour in a novel environment provides clues to the success of an invasive species

“…The difference between sexes in the use of refuge should be related with the sexual system of the species. As in other species of the genus, P. macrodactylus present an important sex dimorphism, with females reaching larger size than males (Berglund, 1981; Vázquez et al, 2012). This characteristic is associated with a “pure searching” mating strategy (Bauer, 2004).…”

“…Its dispersion due the human activity began in the 1950s and currently it has an almost worldwide distribution (Ashelby et al, 2013). Studies carried out on P. macrodactylus ' life history, reproduction and physiological capacity (Béguer et al, 2011; González‐Ortegón et al, 2006, 2013; Lejeusne et al, 2014; Omori & Chida, 1988a, 1988b; Vázquez et al, 2012; Vázquez, Ituarte et al, 2013, Vázquez, Bas et al, 2013) have shown that this species has the potential to live and reproduce successfully in a broad range of conditions, which is certainly important to their success as invader. However, we are far from understanding how these potentially important characteristics can come to operate from the introduction of a few individuals into a new environment.…”