Duration and timing of reproduction in decapod crustaceans of the NW Mediterranean continental margin: is there a general pattern?

Abstract

To describe how decapod crustaceans are adapted to depth, the duration and timing of the reproductive periods of the 19 most abundant species were compared across the continental margin of the NW Mediterranean Sea. Reproductive activity centered on different seasons, depending on genus, but the deepest-dwelling species of this study, i.e. those living at depths from 600 to >1000 m, showed more seasonal reproductive activity than species dwelling in shallower waters, in which reproductive activity occurred year-round. Thus, in genera where 2 or more species were studied (Pasiphaea, Processa, Plesionika, Munida), the duration of the reproductive periods decreased with increasing depth distribution of congeneric species. This pattern was present in epi-mesopelagic, nektobenthic and benthic species. The only exception was the blind palinuran Polycheles typhlops. Suspended particulate matter concentration in the water column generally decreased from the shelf and upper-slope down to the deep-slope region along the 3 seasonal samplings. Furthermore, vertical fluxes collected near the bottom at ~1000 m depth showed a clear seasonal trend. We discuss how differential matter sinking to the benthic ecosystems versus species depth distribution may be the proximal cause of decapod crustacean reproductive seasonality, and how phylogenesis and light intensity should also be taken into account when describing how species are adapted to the transitional depths of the continental margin of the NW Mediterranean Sea.

Reproductive biology of Plesionika narval in the SE Aegean Sea (Eastern Mediterranean)

“…A possible explanation for the seasonality observed on the main reproductive period of P. narval might be seasonal mass fluxes, and that seasonal periods of organic input to the sea bottom would coincide with the main reproductive period, spring and summer months, as already found for other congeneric species in the Northwestern Mediterranean Sea (i.e. Aristeus antennatus, P. acanthonotus) (Company et al, 2003). �owever, species reproductive strategies are based on a complexity of endogenous and exogenous factors such as environmental differences, energy investment, predation, food availability, light intensity, demographic aspects, phylogenetic constraints, phenotypic flexibility, etc.…”

“…Plesionika narval in the Southeastern Aegean Sea, is the main target species in the small-scale trapfishery of the narrow shelf and steep slopes. According to classification of slopes by Company et al (2003), P. narval, would be categorized in the upper shelf (<150 m). Unfortunately, there are not any comparable reproductive patterns except those of P. heterocarpus, in the Northwestern Mediterranean Sea upper slope.…”

Larval stages of the deep-sea lobster Polycheles typhlops (Decapoda, Polychelida) identified by DNA analysis: morphology, systematic, distribution and ecology

“…Previous studies carried out in NW Mediterranean have reported P. typhlops at depths between 300 and 2,000 m and S. sculpta between 1,196 and 2,261 m Cartes et al 1993;Company and Sardà 2000;Company et al 2003Company et al , 2004Follesa et al 2007). Females of both species can be found in shallower depths than males, suggesting a relationship with reproductive behaviour .…”

“…There is some information available on the trophic role of these lobsters (Cartes 1993(Cartes , 1998Maynou and Cartes 1998;Cartes et al 2007;Gastoni et al 2010), but sampling difficulties have prevented scientists from understanding the ecology of polychelids in detail. Knowledge of the reproductive biology of deep-sea species is also scarce and mostly confined to a few species from deep continental slopes and hydrothermal vent habitats (Wenner 1979;Abelló and Cartes 1992;Mullineaux et al 1995;Maiorano et al 1998;Company and Sardà 1998;Company et al 2003;Follesa et al 2007;Cabiddu et al 2008). Similarly, the links that have been established to date between deep-sea benthic adults and pelagic larval forms are uncertain.…”

“…In both P. typhlops and S. sculpta, females attain larger sizes than males, with the largest females being more likely to be found gravid than smaller females. Ovigerous females of P. typhlops have been captured throughout the year in the Western Mediterranean (Abelló and Valladares 1988;Maiorano et al 1998;Company et al 2003;Follesa et al 2007). Gravid females of Stereomastis nana from the western north Atlantic were also caught throughout the year and presented a size-distribution pattern similar to local populations of P. typhlops (Wenner 1979).…”