Pasiphaeid shrimps in the western Mediterranean: geographical variability in distribution and population patterns

Abstract

This work aimed to analyse the main characteristics of the bathymetric and geographic distribution, population size structure and size at maturity of the continental slope caridean shrimps Pasiphaea sivado and Pasiphaea multidentata in the western Mediterranean, as well as to try to relate the patterns obtained with geomorphologic and hydrographic characteristics. The study area encompassed the Mediterranean coast of the Iberian Peninsula. In both species, marked differences in depth distribution, density, and population size structure were found between Algerian basin populations, particularly in the Alboran Sea, and those in the Catalano-Balearic basin. Both shrimps showed a shallower bathymetric range in the westernmost region of the Algerian basin than in the rest of geographic sectors, linked to the occurrence of upwelling areas on the northwestern edges of the Alboran Sea. Populations of P. sivado reached larger densities, sizes and maturity size in the Algerian basin. No recruitment of P. multidentata was detected in the Algerian basin, whereas it was present in the Catalano-Balearic basin. In both species, the window range of bottom temperature and salinity was larger in juveniles than in adults. These different distribution and population dynamics imply that ecological functioning of these species differs between the two geomorphological basins of the western Mediterranean Sea.

Sexual dimorphism and associated population characteristics in the benthopelagic shrimp <em>Pasiphaea sivado</em> (Crustacea: Caridea: Pasiphaeidae)

“…The size at which differences in sex ratio become significant has also been suggested to be an indirect indicator of the size at puberty moult and/or maturity size/age of the species (Abelló et al 1990). In the present study, the precise size at which males outnumbered females progressively decreased from the Alboran Sea to the Alacant area and the Catalan Sea, corroborating the patterns of size structure and size at maturity observed in this area (Simão et al 2015) and implying the occurrence of environmental and ecological processes affecting growth rates.…”

“…In the Catalan Sea, the absence of gender segregation by depth was also reported by Company et al (2001) throughout the year, and could be related to the gregarious behaviour of macroplankton/micronekton organisms (McManus and Woodson 2012). During the daytime, P. sivado inhabits the epi-/suprabenthic environment over the upper and medium slope, with high densities recorded when sampled by demersal trawl nets during fishery research surveys (Cartes et al 2007, García-Rodríguez et al 2011, Simão et al 2015, while during the night the species has been reported to migrate several hundred metres up the water column to waters near the surface to feed on plankton (Froglia and Giannini 1982, Cartes 1993, Simão et al 2014.…”

“…No significant differences in SFD variation with depth were detected in the Alacant area and Catalan Sea populations. It is worth noting that despite intensive sampling, the densities of P. sivado at certain depths and areas are very low (Simão et al 2015): the species is hardly found shallower than 200 m, except in the Alboran Sea, and deeper than 600 m throughout the study area. …”

“…These sectors were established according to previous results (Simão et al 2015), in which differences in size at maturity were observed between Alboran Sea populations and the rest of the sampled populations along the Iberian Peninsula Mediterranean coasts. Sex ratio was not calculated in size classes with fewer than 25 individuals.…”

Capoeira Angola Diversifying the University: sowing an Ecology of Knowledges in the Performing Arts

“…It is necessary to listen to the masters and bring them to teach, without interfering with their personal way of teaching. What is expected is to seek "[…] an identity that is not the one imposed by Europeans, even if their influences remain" in our bodies and minds (Simão;Sampaio, 2018, p. 674).…”