Considerations on the biology of <i>Plesionika edwardsi</i> (Brandt, 1851) (Decapoda, Caridea, Pandalidae) from experimental trap catches in the Spanish western Mediterranean Sea

Abstract

SUMMARY: In this study, the results obtained from three experimental trap shrimp (Plesionika edwardsi) fishing cruises in three different seasons are presented. They were carried out during a total of 50 days, of which 43 days were of effective fishing, covering the whole Spanish Mediterranean coast including the island of Alborán. On the whole, the fishing depth varied between 220 and 384 m, with a mean depth of 318 m. The target species appeared in 81% of the total samples carried out, with a mean yield (cpue) of 108.6 g/trap/day. The largest yields (cpue) of this species were from the Balearic islands, followed by Levant region, whereas the Alborán sea gave the lowest yields. The largest mean length was observed on the Levant zone, but on the contrary the smallest mean lengths were found towards the south, more specifically at Alborán island. Significant differences were found in both the relative and absolute growth, between males and females, with equilibrium in the ratio of the sexes (0.49). A total of 15 crustacean and 12 fish species were identified as accompanying fauna, with Conger conger, Plesionika narval and Scyliorhinus canicula being the most important, based on their mean cpue, although differences in the appearance and yields of the species were found in the different zones and depths. However, the mean yields of these species were very low, due to the high selectivity of the fishing gear used. The appearance of Heterocarpus ensifer, deserves a special mention, since it is the second documented record of the species in the Mediterranean.

Life Cycle of the Deep-Water Pandalid Shrimp Plesionika Edwardsii (Decapoda, Caridea) in the Central Mediterranean Sea

“…4, 2002 cies as well as other Pandalidae species. This confirms the reports of previous experimental trap surveys conducted in other areas: the South Pacific (King, 1986;Poupin et al, 1990), Indian Ocean (Lebeau, 1976), SouthEast Atlantic (Martins and Hargreaves, 1991;Biscoito, 1993;González and Santana, 1996), Mediterranean (Secci et al, 1994;García-Rodríguez et al, 2000). The traps attracted Pandalid shrimp at night when shrimp increase in abundance near the bottom in response to reduced predatory activity.…”

“…In the present study, the yield obtained was similar to that reported for the western Mediterranean (García-Rodríguez et al, 2000) and did not show any significant change related to either season or depth. The high variability showed by CPUEs could be caused by both the distribution of P. edwardsii shoals along the continental slope and the size of the fishing rip used.…”

“…In the western Mediterranean, Sardà (1997, 2000) analysed the reproductive characteristics and growth of the species using trawl survey data. In the same area, García-Rodríguez et al (2000) described the biology of the species using commercial trap catches, while Cartes (1993a, b) and Cartes et al (1993) studied its diet and diel cycle of activity, respectively. Other information on the life-cycle variables of the species come from the Canary Islands (Santana et al, 1997), the South Pacific (King, 1984(King, , 1986Poupin et al, 1990), and the Indian Ocean (Intes and Bach, 1989).…”

Stock boundaries for fisheries assessment and management in the Mediterranean: the Balearic Islands as a case study

“…Firstly, we analyzed the population structure of all five species using data taken on board commercial trawlers and scientific vessels (MEDITS), testing differences in Mediterranean (GFCM). The inlet details GSA05 (Balearic Islands) and GSA06 (Northern Spain) showing the names of several ports from GSA06 and the different islands of the Balearic Archipelago mentioned in the work; the isobaths are 100 and 800 m. Red shrimp and caridean shrimp fishing grounds of GSA05 exploited by trawlers from GSA06 are also shown in dark grey and grey respectively (adapted from García-Rodríguez and Esteban, 1999;and García-Rodríguez et al 2000). size distributions between GSAs with the KolmogorovSmirnov test.…”

“…With the exception of a few vessels of GSA06 working in waters of GSA05 around Ibiza-Formentera (García-Rodríguez and Esteban 1999) and along the eastern slope of Mallorca and Menorca (García-Rodríguez et al 2000), the demersal fleets of the two purse-seine) in the geographical sub-areas Balearic Islands (GSA05) and Northern Spain (GSA06).…”