Abstract. — The spatio-temporal 

 structure of a population of the 

 deep-water shrimp Aristeus anten- 

 natus on the fishing grounds off 

 Barcelona, Spain, in the western 

 Mediterranean Sea was studied, 

 and the relationship between fluc- 

 tuations in catch of this species and 

 spatio-temporal changes in the size 

 and sex composition of shoals is 

 described. Fluctuations were moni- 

 tored by using a sample design 

 based on fixed seasonal sampling 

 of three different habitats (upper 

 submarine canyon, middle slope, 

 and lower slope). The results ex- 

 plain changes in fishing fleet and 

 fishing location. The stock appears 

 to remain constant at approxi- 

 mately optimum levels of exploita- 

 tion because part of it is unex- 

 ploited below 1,000 m. 



Factorial correspondence analy- 

 sis indicated a generally strong in- 

 fluence of depth on the abundance 

 of deep-water shrimp, explaining 

 63.14% of the variance. However, 

 the influence of seasonality was 

 stronger when only samples taken 

 at depths shallower than 1,000 m 

 (75.22%) were considered. Females 

 contributed most to the catches on 

 the upper and middle slope throug- 

 hout the year, and catches of fe- 

 males were strongly related to sea- 

 sonality (P<0.05 1. The combined in- 

 teraction of depth and seasonality 

 on the abundance of males was sig- 

 nificant (P<0.05). Juveniles were 

 present in the catches from autumn 

 to spring, and the combined effect 

 of depth and seasonality on the 

 abundance of juveniles was also 

 significant (P<0.05). The role of the 

 regional submarine canyon as a 

 zone of higher energy and biomass 

 in the recruitment of this species 

 is discussed, and the importance of 

 spatio-temporal factors linked to 

 the life cycle of deep-water shrimps 

 is highlighted. The results demon- 

 strate that comprehensive ecologi- 

 cal studies of exploited species are 

 essential to proper fisheries man- 

 agement. 



Spatio-temporal structure of the 

 deep-water shrimp 

 Aristeus antennatus 

 (Decapoda: Aristeidae) population 

 in the western Mediterranean 



Francisco Sarda 

 Joan E. Cartes 

 Walter Norbis* 



Institute de Gencias del Mar (CSIC). Paseo Nacional s/n 

 08039 Barcelona, Spam 



As fishing activity has expanded 

 into deeper waters, deep-water 

 shrimps (Dendrobranchiata and 

 Caridea) have become an important 

 resource in different parts of the 

 world, e.g. Australia (King, 1981; 

 King and Butler, 1985) northern 

 Europe (Anon., 1992), and the Pa- 

 cific (Gooding, 1984) and Indian 

 (Jones, 1969) oceans. In the Medi- 

 terranean Sea in particular, these 

 shrimps are the target of a tradi- 

 tional fishery (Relini and Orsi 

 Relini, 1987; Tobar and Sarda, 1987; 

 Campillo et al., 1990; Demestre, 

 1990; Demestre and Lleonart, 

 1993). In addition, deep-water 

 shrimps, particularly aristeid species 

 (Dendrobranchiata, Penaeoidea: 

 Aristeus antennatus Risso, 1816), 

 play an important ecological role in 

 Mediterranean deep-sea communi- 

 ties at depths below 400 m (Peres, 

 1985; Abello et al., 1988; Abello and 

 Valladares, 1988; Cartes and Sarda, 

 1993). Population structure, biologi- 

 cal cycles, life history, and spawn- 

 ing strategies of deep-water 

 shrimps differ from those of littoral 

 species (Garcia and Le Reste, 1987) 



and are poorly understood. The life 

 history of deep-water penaeoidean 

 species is not dependent upon la- 

 goonal or littoral systems, and 

 growth in such species tends to be 

 slower than that in littoral penaeid 

 species (Garcia and Le Reste, 1987; 

 Demestre, 1990). The presence and 

 abundance of such species are 

 linked to the topography of the con- 

 tinental slope and submarine can- 

 yons. However, their behavioral pat- 

 terns are complex and not well un- 

 derstood (Tobar and Sarda, 1987; 

 Cartes et al., 1993). 



Pandalus borealis (Anon., 1992) 

 (Pandalidae, Caridea) is the most 

 extensively studied shrimp species 

 from a fisheries perspective. This 

 species exhibits major differences 

 with respect to species of other gen- 

 era inhabiting subtropical deep-sea 

 regions, such as Aristeus, Aristaeo- 

 morpha, Parapandalus, and Ples- 

 ionika; it is protandrously herma- 

 phroditic and distributed in shallower 

 waters. Migratory patterns, short and 

 medium-term fluctuations in abun- 

 dance, aggregating behavior, recruit- 

 ment, and larval and postlarval dis- 



Manuscript accepted 30 November 1993. 

 Fishery Bulletin 92:599-607 ( 1994). 



' Permanent address: INAPE, Constituyente, 1497 

 CP 11200. Montevideo, Uruguay 



599 



