Abundance and population structure of Plesionika narval (Fabricius, 1787) in the Northeastern Atlantic

Abstract

Analysis of abundance and population structure of Plesionika narval was performed on data concerning 5,255 specimens obtained from 62 fishing sets carried out off the Madeira archipelago (Northeastern Atlantic) between 2004 and 2008 in a depth range from 101 to 350 m. Abundance ranged from 0.01 to 19.74 specimens-per-trap and significant differences were found between seasons, probably as a result of an increment of population in the spring during the recruitment season. The analysis of size distribution revealed that the carapace length (CL) ranged from 2.45 to 28.61 mm and that mean female size consistently exceeded that of males. Differences in mean CL were statistically significant between depth strata and seasons. Of the specimens sampled, 57.00% were males, 41.88% females and 1.42% undetermined. Sex ratio also differed significantly between seasons according to depth strata, consolidating the hypothesis of the existence of seasonal migrations related with the reproductive cycle of this species. Ovigerous females showed larger sizes and occurred all year around and remain in shallow waters in winter, summer and autumn and move to deeper waters in spring. The highest frequency of ovigerous females was recorded in summer, between 151 and 200 m deep supporting the hypothesis that spawning of this species occurs in shallow waters, especially in late summer.

Weight-length relationships of six shrimp species caught off the Madeira Archipelago, Northeastern Atlantic

“…The WLR is a practical condition index and may vary temporally according to factors such as food availability, feeding rate and reproductive activity, however the b parameter usually does not vary significantly throughout the year (Bagenal and Tesch, 1978), and together with a (condition factor) can be considered mean annual values, as suggested by several authors (Santos et al, 2002;Andreu-Soler et al, 2006). The results indicate a strong pattern of negative allometric growth in the studied species of nektobenthic shrimps off the coast of Madeira which is in accordance with previous studies for pandalid shrimps P. edwardsii, Plesionika antigai Zariquiey Álvarez, 1955, Plesionika gigliolii (Senna, 1902, P. narval, Plesionika heterocarpus (A. Costa, 1871) and P. martia (Martins and Hargreaves, 1991;González et al, 1997González et al, , 2016Company and Sardà, 2000;Maiorano et al, 2002;Thessalou-Legaki et al, 2005;Vafidis et al, 2008;Sousa et al, 2014). The same pattern is also well known for Aristaemorpha foliacea (Risso, 1827) (Ragonese et al, 1997), Aristeus antennatus (Risso, 1816) (Carbonell et al, 1999 and Heterocarpus laevigatus (Dailey and Ralston, 1986).…”

“…Regardless of its economic and ecological importance and fishery potential, very few documented studies are available on WLRs, biology, population dynamics and condition factor of the shrimp species in this area. The few studies have focused on the biology of Heterocarpus ensifer Spence Bate, 1888 (Pérez-Peñalvo et al, 2009), Plesionika narval (Fabricius, 1787) (Sousa et al, 2014) and Plesionika edwardsii (Brandt, 1851) (González et al, 2016) in this region.…”

First Macro-Colonizers and Survivors Around Tagoro Submarine Volcano, Canary Islands, Spain

“…Another dominant colonizer was the shrimp Plesionika narval ( Figure 8F and Table 1), represented by adult and juvenile individuals (high visualization rate in the underwater images), and it is also a common component of the Macaronesian circalitoral bottoms. In this context, its presence in the TVC could be primarily due to horizontal movements of individuals from nearby habitats [52,53]. This could also be the case for the few fish species observed in the TVC and its surrounding areas, Anthias anthias being by far the most abundant species.…”

Premium small scale: the trap fishery for Plesionika narval (Decapoda, Pandalidae) in the eastern Mediterranean Sea

“…Our findings on the dependence of CPUE and profits on seasonal, spatial and technical parameters can be used to improve the management of this valuable fishery. The insights gained are also relevant to other similar trap fisheries with high local importance in the Mediterranean and beyond, if tailored to the specific characteristics of these other fisheries through dedicated case studies (Garcia-Rodriguez et al, 2000;Gonzalez et al, 2001;Colloca, 2002;Castriota et al, 2004;Arrasate-Lopez et al, 2012;Sousa et al, 2014).…”

“…Plesionika narval (Fabricius, 1787) and other sympatric Pandalid species form localized aggregations that support SSFs in Greece (southeastern Aegean Sea; Thessalou-Legaki et al, 1989;Kalogirou et al, 2017), Italy (south Tyrrhenian Sea; Colloca, 2002;Castriota et al, 2004) and the Spanish Mediterranean shelf (Garcia-Rodriguez et al, 2000). Similar SSFs for Pandalid shrimps also operate in some eastern Atlantic islands, such as the Canary Islands (Gonzalez et al, 1997, 2001Arrasate-Lopez et al, 2012), Madeira (Sousa et al, 2014) and the Azores (Martins & Hargreaves, 1991). The Greek SSF targeting P. narval operates in the Dodecanese archipelago (southeastern Aegean Sea) ( Fig.…”