LIFE HISTORY OF PLESIONIKA EDWARDSI (CRUSTACEA, DECAPODA, PANDALIDAE) AROUND THE CANARY ISLANDS, EASTERN CENTRAL ATLANTIC

S. Afr. J. mar. Sci. 18: 39 48 1997 39 LIFE HISTORY OF PLESIONIKA EDWARDSI (CRUSTACEA, DECAPODA, PANDALIDAE) AROUND THE CANARY ISLANDS, EASTERN CENTRAL ATLANTIC J. I. SANTANA*, J. A. GONZÁLEZ*, I. J. LOZANO ad V. M. TUSET* The life history of Plesioika edwardsi (Bradt, 1851) aroud the Caary Islads i the Easter Cetral Atlatic was ivestigated, based o a total of 11 434 shrimps ragig i legth betwee 8 ad 40 mm carapace legth (CL). The species carries out seasoal migratios; they cocetrate i deep water durig witer, move shallower i summer ad retur to deep water agai i autum. Ovigerous females occur throughout the year, but a spawig peak was determied betwee April ad September. The size at maturity for females was approximately 26 mm CL. Shrimp size geerally icreased with icreasig water depth. The growth parameters for males were L = 25.75 mm CL ad K = 0.55 year -1, ad L = 28.28 mm CL ad K = 0.66. year -1 for females. The species displays the typical reproductive patter of tropical padalids ad is dioecious. Plesioika edwardsi (Bradt, 1851) is a marie species of wide distributio at low latitudes. It is kow from the Wester Pacific (Philippies, Idoesia), the Wester Atlatic (from South Carolia ad North Bahamas to the Gulf of Mexico), the Easter Atlatic (from North-West Spai to Sierra Leoe, icludig the archipelagos of Azores, Madeira, Caaries ad Cape Verde ad most of the Mediterraea), ad the South-Wester Idia Ocea aroud the Seychelles (Crosier ad Forest 1973, Holthuis 1980, 1987, Chace 1985, Itès ad Bach 1989, Gozález et al. 1990, Frase 1991, Martis ad Hargreaves 1991, Biscoito 1993). Those authors have recorded the species at bottom depths of 54 700 m o mostly muddy substrata, but also o sady or rocky bottoms over the cotietal shelf ad upper cotietal slope. P. edwardsi has bee icluded i the F. A. O. catalogue of species of iterest to fisheries (Holthuis 1980). Zariquiey Álvarez (1968) reported it as beig caught by trawlers off the Mediterraea coast of Spai. It is believed to be of some ecoomic iterest i Spai, Italy, Morocco, Algeria ad Tuisia, where it is sold i fish markets with other shrimps (Holthuis 1980, 1987). Sice 1984, P. edwardsi has bee caught i abudace with multiple shrimp traps o the steep grouds betwee 75 ad 500 m deep i the Wester Mediterraea (the east coast of Spai, Balearic Islads, Corsica, Sardiia ad Sicily). Durig the period 1984 1991, aual Spaish catches varied betwee 80 ad 100 tos (Gozález et al. 1992). Itès ad Bach (1989) reported the species to be of ecoomic iterest i the Seychelles. Despite its abudace ad widespread distributio, P. edwardsi has ot bee studied i much detail (e.g. Kig 1986, Itès ad Bach 1989, Martis ad Hargreaves 1991). The results of more tha 20 fishig surveys i the deep waters aroud the Caary Islads have suggested that P. edwardsi ad Heterocarpus esifer are occasioally abudat ad of possible, but restricted, ecoomic iterest (e.g. Sataella ad Bravo de Lagua 1975, Gozález et al. 1988, Caldetey et al. 1992, Gozález 1995). Off the Azores, a trial fishery usig bottom traps at depths ragig betwee 18 ad 864 m showed that the most commo ad abudat shrimp caught there was Plesioika arval, followed by P. edwardsi (Martis ad Hargreaves 1991). I the archipelago of Madeira, exploratio with bottom traps dow to 1 000 m (et at depth) revealed that P. arval was the most abudat padalid shrimp, but large catches of P. edwardsi were take betwee 130 ad 360 m (Biscoito 1993). Aroud the Caary Islads, P. arval is the target species of a small artisaal fishery o the arrow shelves ad steep slopes of the wester ad cetral islads. Fishig is carried out with bottom shrimp traps set maily betwee 100 ad 150 m water depth. P. arval represets umerically ad by mass about 85% of the total shrimp catch, the remaiig percetage cosistig of P. edwardsi, H. esifer ad other sublittoral shrimps. Although fisheries statistics are ot available, up to 10 tos of padalid shrimps might be caught aually. This study provided iformatio o the basic biology ad biological parameters of P. edwardsi aroud the Caary Islads. The paper cotributes to the * Istituto Caario de Ciecias Marias, D.G. Uiversidades e Ivestigació, Gobiero de Caarias, P.O. Box 56, E-35200 Telde (Las Palmas), Spai. E-mail: solea@iccm.rcaaria.es Departameto de Biología Aimal, Uiversidad de La Lagua, Astrofísico F. Sáchez s/, E-38206 La Lagua (Sata Cruz de Teerife), Spai Mauscript received: April 1996

40 South Africa Joural of Marie Sciece 18 1997 Table I: Cruise ad samplig iformatio of shrimps take betwee 1974 ad 1994 aroud the Caary Islads Cruise Date Islad Latitude ( N) Logitude ( W) Sample size Size rage Depth rage (m) (CL, mm) AGAMENÓN 7406 MOGÁN 8701 MOGÁN 8701 MOGÁN 8710 MOGÁN 8802 MOGÁN 8804 MOGÁN 8804 MOGÁN 8806 GOMERA 9009 CANARIAS 9206 CANARIAS 9206 TALIARTE 9403 BOCINEGRO 9412 Jue 1974 Jue 1985 Jue 1985 Jue 1985 Jue 1985 Jue 1985 Jue 1985 Jue 1985 July 1985 July 1985 Jauary 1987 February 1987 October 1987 February 1988 April 1988 May 1988 Jue 1988 Jauary 1990 February 1990 July 1990 August 1990 September 1990 September 1990 October 1990 November 1990 May 1992 Jue 1992 March 1994 December 1994 P CF L TG H P C FC C CC C CC T TT T TG T TT T CC 28 35 27 40 28 06 28 09 28 45 28 56 29 16 27 59 28 25 27 59 28 15 27 41 28 39 27 41 27 43 28 47 27 46 27 52 27 46 27 52 27 43 27 45 27 43 27 45 27 43 27 45 27 43 27 45 27 43 27 45 27 58 28 18 28 06 28 20 28 19 27 59 27 59 28 08 28 21 17 57 15 42 15 52 13 47 14 02 13 34 13 51 16 33 16 38 17 14 17 21 18 02 17 58 15 46 15 47 13 48 14 27 14 50 15 00 14 50 15 00 15 47 15 49 15 47 15 49 15 47 15 49 15 47 15 49 15 47 15 49 17 12 17 18 16 46 16 57 16 43 16 57 15 18 15 20 00620 00607 00001 00049 00189 00378 00396 00225 00024 00214 00354 00509 03 751 01 841 00449 00021 00085 00015 00002 00014 00012 00025 00361 00073 00138 00164 00393 00514 00010 16 40 000031 21 35 13 33 17 33 14 33 18 33 19 35 15 34 08 34 08 33 12 36 20 34 16 33 17 28 17 21 09 24 10 26 08 23 08 31 09 26 09 25 14 29 12 29 11 29 19 29 165 329 176 384 0000137 135 366 161 347 146 165 128 322 095 468 219 332 161 409 135 405 180 315 125 270 128 285 121 286 000 0301 247 265 262 357 0000 98 128 201 121 158 140 160 054 266 113 200 112 144 337 350 119 403 250 386 0000100 Total 1974 1994 27 40 29 16 13 34 18 02 11 434 08 40 054 468 P = La Palma, C = Gra Caaria, F = Fuertevetura, L = Lazarote, T = Teerife, G = La Gomera, H = El Hierro

1997 Sataa et al.: Life History of Plesioika edwardsi aroud Caary Islads 41 Fig. 1: Depth distributio of P. edwardsi off the Caary Islads, expressed i terms of cpue: total catches ad catches of ovigerous females preseted separately kowledge of the life history of this padalid species, ad may be of future importace should it become ecessary to assess ad maage the stock. MATERIAL AND METHODS About 12 research surveys were made to the Caary Islads i the Easter Cetral Atlatic be- Table II: Effort ad mass of total ad ovigerous shrimps caught per 50 m depth iterval Mass caught (g) Depth iterval Effort (umber (m) of traps) Total catch Ovigerous shrimps 051 100 101 150 151 200 201 250 251 300 301 350 351 400 401 450 451 500 Total 020 101 054 058 060 017 012 005 001 328 00152 11 790 14 235 20 502 20 736 01 450 00174 00202 00007 69 248 00049 3 803 6 868 9 500 9 164 00268 00035 00108 00000 29 795 Fig. 2: Seasoal depth distributio of P. edwardsi off the Caary Islads. Data expressed i terms of cpue: total catches ad catches of ovigerous females preseted separately

42 South Africa Joural of Marie Sciece 18 1997 Fig. 3: Mothly frequecies of ovigerous females i the populatio of P. edwardsi off the Caary Islads twee 27 41 29 16 N ad 13 34 18 02 W durig the period 1974 1994 (Table I). Durig these cruises, bottom traps were set o the isular shelf ad slope regios at depths ragig from 54 to 468 m depth (e.g. Sataella et al. 1975, Sataa et al. 1987, Gozález et al. 1988, Lozao et al. 1990a, b, 1992, Herádez et al. 1991, López Abellá et al. 1994, Fig. 5: Size frequecy distributios of (a) o-ovigerous ad ovigerous ad (b) male ad female P. edwardsi off the Caary Islads Fig. 4: Relatioship betwee frequecy of ovigerous females ad carapace legth of P. edwardsi off the Caary Islads Gozález 1995). A total of 11 434 P. edwardsi was studied from these cruises, from which 75.6% were measured (size rage 8 40 mm carapace legth, Table I). P. edwardsi was ot targeted durig the research surveys, which formed part of a larger study o the etire padalid shrimp assemblage. Therefore, fishig effort across the bathymetric rage from 50 to 500 m was more or less equally distributed over each 100 m depth iterval. Differeces i the actual umber of traps set per 50 m depth iterval reflect variable weather coditios (Table II). Most of the specimes caught were separated with respect to their ovigerous or o-ovigerous coditio ad couted. The carapace legth (CL) of a subsample from each group was measured (± 0.1 mm) dorsally

1997 Sataa et al.: Life History of Plesioika edwardsi aroud Caary Islads 43 from the posterior edge of the eye socket to the posterior edge of the carapace usig a verier caliper. The total wet mass (W) of each shrimp was measured (± 0.1g), mostly from fresh material. The sex of oovigerous idividual samples (females, males ad sexually uidetified specimes) was determied after 1985, accordig to the presece/absece of the appedix masculia o the edopod of the secod Males Sex/Group Table III: Seasoality i mea size of shrimps per 50 m depth iterval Value per depth iterval (m) Seaso 101 150 151 200 201 250 251 300 301 350 351 400 Jauary March Mea size (CL, mm) 00 14.1 000 1.8 0 102.0 19.6 4.6 46.0 21.6 3.8 126.0 April Jue Mea size (CL, mm) 00 21.4 00 03.5 0 168.0 19.7 4.1 139.0 22.1 4.1 139.0 July September Mea size (CL, mm) 013.7 005.2 124.0 Females Jauary March Mea size (CL, mm) 00 14.5 000 2.6 0 186.0 24.9 4.0 650.0 25.6 3.4 102.0 April Jue Mea size (CL, mm) 0023.6 0006.3 0104.0 025.4 003.6 145.0 00 26.6 00 3.8 0 321.0 27.1 4.6 382.0 25.2 3.1 62.0 No-ovigerous shrimps July September Mea size (CL, mm) October December Mea size (CL, mm) Jauary March Mea size (CL, mm) 0025.8 0002.3 0125.0 024.8 004.0 163.0 026.9 002.5 254.0 00 27.4 000 2.0 0 393.0 0014.1 000 1.8 281 21.3 5.0 1 428.0 21.6 4.1 151.0 April Jue Mea size (CL, mm) 0018.6 0003.9 0069.0 021.9 003.5 127.0 00 22.2 000 3.5 0 346.0 23.1 4.9 433.0 23.2 3.3 181.0 July September Mea size (CL, mm) 016.1 006.5 194.0 00 18.3 0007.5 0075.0 October December Mea size (CL, mm) 0020.6 0003.3 1 106.0 021.7 003.1 672.0 0 022.2 00 03.6 1 317.0 22.8 5.0 72.0

44 South Africa Joural of Marie Sciece 18 1997 Table III (cotiued) Sex/Group Ovigerous females Value per depth iterval (m) Seaso 101 150 151 200 201 250 251 300 301 350 351 400 Jauary March Mea size (CL, mm) 26.4 2.3 370.0 26.5 1.6 86.0 April Jue Mea size (CL, mm) 26.4 2.9 123.0 28.1 3.2 219.0 29.2 3.2 256.0 July September Mea size (CL, mm) 24.7 3.7 144.0 October December Mea size (CL, mm) 25.8 2.2 125.0 26.9 2.5 252.0 27.4 2.0 392.0 pleopod (Kig ad Moffitt 1984). Shrimp abudace was estimated idirectly usig catch-per-uit-effort (cpue) data (i.e. mass of shrimp per trap). The seasoal distributio of shrimp size ad depth was ivestigated at 50 m depth itervals. The mass of shrimp per trap was calculated separately for ovigerous females ad total shrimp. Sexes were treated separately, ad samples cosistig of <40 idividuals were ot aalysed. The spawig seaso was determied from the mothly frequecy of ovigerous females. A sexual maturity curve was derived usig a logistic fuctio (Pope et al. 1983). The mea legth (CL) at maturity i females was calculated as the legth at which 25% of the populatio was ovigerous (Kig ad Butler 1985). Legth frequecy data were aalysed to estimate growth of each sex, accordig to the method of Pauly (1983). Legth frequecies of samples from Table IV: Statistical data o the size of the shrimps examied Parameter Males Females Number of observatios Mea size (CL, mm) Rage (mm) 009060 000019.1 000005.0 8.0 34.0 03 0140 000025.3 000004.8 8.0 39.9 No-ovigerous shrimps 6 5740 000 21.2 0000 4.6 8.0 35.0 Ovigerous females 002 1640 0000027.1 0000003.1 12.6 39.9 September 1990 (for males) ad Jue 1992 (for females) were repeated over five ad six years respectively to simulate the time sequece of the samples accordig to the priciples of Pauly s method. The Hasselblad s maximum likelihood method was used to separate the ormal distributio of mixtured samples. The growth performace of both sexes (Muro s phi prime) was compared, accordig to Sparre et al. (1989). Normality of the legth data was determied usig the Kolmogorov-Smirov test (Sokal ad Rohlf 1981) prior to comparig the mea size of differet groups of shrimps. The same test was used to compare legth frequecy distributios. The Ma- Whitey U test was applied as a o-parametric test to compare idepedet samples (Sokal ad Rohlf 1981). Sex ratios were aalysed by size-class. The relatioship betwee CL ad W was calculated for each sex (or group) over the etire study period usig the equatio W = acl b. RESULTS P. edwardsi has bee caught at depths from 54 m (cruise Gomera 9009 ) to 468 m (cruise Caarias 85 ) i the waters aroud the Caary Islads. Maximum estimates of abudace rage betwee 264 ad 353 g. trap 1 for total shrimps ad betwee

1997 Sataa et al.: Life History of Plesioika edwardsi aroud Caary Islads 45 Fig. 6: Relatioship betwee sex ratio frequecy (females x 100/(males + females) ad size of P. edwardsi off the Caary Islads 127 ad 164 g. trap 1 for ovigerous females. These catches were take from depths ragig from 151 to 300 m (Fig. 1). The P. edwardsi populatio was cocetrated betwee 250 ad 300 m deep (total shrimps = 491 g.trap 1, ovigerous females = 168 g.trap 1 ) durig the period Jauary March. The populatio was more homogeeously distributed from April to Jue, whe it occurred over a wider depth rage of 150 300 m (total shrimps = 198 241 g. trap 1, ovigerous females = 144 155 g. trap 1, Fig. 2). Durig the moths July- September, P. edwardsi was cocetrated at 150 250 m (total shrimps = 163 121 g. trap 1, ovigerous females = 146 73 g. trap 1 ). Although the populatio occupied a wide depth rage (100 300 m) from October to December, it was most abudat at 250 300 m (total shrimps = 721 g. trap 1, ovigerous females = 300 g. trap 1, Fig. 2). Females carried eggs throughout most of the year, with the percetage of ovigerous females i the populatio varyig betwee 9.2 ad 50.4% i May ad July respectively (Fig. 3). The sexual maturity curve for female P. edwardsi (Fig. 4) shows that maturity (25% of the populatio) was reached at 26 mm CL. The distributio of the mea shrimp sizes over each depth iterval durig each seaso is preseted i Table III. I geeral, the size of females (both o-ovigerous idividuals ad ovigerous females) teded to icrease with icreasig depth. However, this tred was ot apparet durig the secod quarter of the year for shrimps caught betwee 301 ad 350 m deep. There was o clear tred i males because of isufficiet data. The legth statistics of the shrimps examied by sex ad reproductive group are summarized i Table IV. Material collected from aroud the Caary Islads raged i legth from 8 to 40 mm CL, ad shrimps betwee 20 ad 29 mm CL represeted 66% of the total sample (Fig. 5). Males raged from 8 to 34 mm CL ad females betwee 8 ad 40 mm CL. No-ovigerous shrimps raged from 8 to 35 mm CL ad ovigerous females betwee 13 ad 40 mm CL (Fig. 5). There were sigificat differeces i the legth frequecy distributios of P. edwardsi by sex ad group (Table V). Females were sigificatly larger tha males (25.3 mm ad 19.1 mm CL respectively), whereas ovigerous females were sigificatly larger tha o-ovigerous idividuals (27.1 mm ad 21.2 mm CL respectively). Females domiated the bigger legth-classes (20.0 40.9 mm), whereas sexes were equally represeted i the 12 29 mm legth rage (Fig. 6). It was ot possible to determie sex ratios i the smaller legth-classes (8.0 11.9 mm). Aalyses of the legth frequecy data showed the presece of four modes i males ad five i females (Table VI). Subsequet aalysis of modal progressio provided differet values of L (25.75 ad 28.28 mm) ad K (0.55 ad 0.69 year 1 ) for males ad females respectively. Based o the phi prime idex, females (Φ = 2.74) seem to have faster growth rates tha males (Φ = 2.56). Table VII lists the relatioships betwee carapace legth ad wet mass for each sex ad group. Mass Table V: Statistical compariso of legth distributios ad mea sizes of shrimps examied Number of observatios Number of observatios No-parametric test Z p Z p Males Females No-ovigerous Ovigerous shrimps females Kolmogorov-Smirov 906 3 014 014.77 *** 6 574 2 164 024.64 *** Ma-Whitey U 906 3 014 30.46 *** 6 574 2 164 51.23 *** z = Desity fuctio of ormal probability *** p < 0.001

46 South Africa Joural of Marie Sciece 18 1997 Table VI: Normal legth distributios of male ad female P. edwardsi derived by the maximum likelihood method Number of observatios 66.00 34.00 37.95 10.19 31.43 56.41 45.87 09.10 SI = Separatio idex Mode (CL, mm) 09.792 16.699 20.329 18.250 21.318 23.512 25.697 28.083 icreased with egative allometry, the coefficiet b varyig betwee 2.298 ad 2.778. All relatioships were sigificat (p < 0.01) ad the high r 2 values idicated a good fit to the data. DISCUSSION SI χ 2 df Males 1.132 0.659 1.350 Females 1.638 1.325 0.865 0.709 0.594 7.715 3.614 000 2.071 2.005 2.777 3.664 11.449 Off the Caary Islads, P. edwardsi has bee collected from 54 m to at least 468 m, maily from 150 to 300 m. The species is commoly caught betwee 250 ad 380 m off the Mediterraea coasts (Holthuis 1987) ad at 300 500 m off the coast of North Africa (Crosier ad Forest 1973). Although the preset results suggest that P. edwardsi ihabits shallower waters aroud the Caary Islads, it has bee recorded from equally shallow water aroud the Azores (Martis ad Hargreaves 1991). The other commo padalid shrimps, P. arval, is most frequetly caught betwee 20 ad 200 m off the Caary Islads, maily from 50 to 175 m (Gozález et al. 1997). The preset results suggest that P. arval may be replaced by P. edwardsi with icreasig depth. P. edwardsi teds to cocetrate i deep water i witer, moves shallower durig sprig, reaches its shallowest depths i summer ad returs to deep water agai i autum. A similar distributio patter, based o seasoal vertical movemets, has also bee reported for P. arval off the Caary Islads (Gozález et al. 1997) ad i the Easter Mediterraea (Thessalou-Legaki et al. 1989). Ovigerous females of P. edwardsi were preset throughout most of the year, with peak spawig activity from April to September. Ovigerous females of this species were observed betwee Jauary ad 3 10 Table VII: Regressio statistics (y = ax b ) for the relatioships betwee carapace legth (CL, mm) ad wet body mass (g) by sex ad reproductive group of P. edwardsi Sex/Group a ( 10-4 ) b r 2 Males Females No-ovigerous shrimps Ovigerous females For all regressios p < 0.01 34.964 12.143 12.193 59.448 2.439 2.778 2.757 2.298 0.874 0.931 0.941 0.843 00906 3 014 6 574 2 164 March off the Azores (Martis ad Hargreaves 1991), from Jauary to August off the Iberia Peisula (Zariquiey Álvarez 1968) ad throughout the year i the Mediterraea (Holthuis 1987). Wide spawig seasos have also bee reported for some cogeeric species: P. arval off the Caary Islads (Gozález et al. 1997), P. heterocarpus off the Mediterraea coasts (Holthuis 1987) ad P. martia i the Mediterraea ad the Easter Cetral Atlatic (Zariquiey Álvarez 1968, Lagardère 1981, Holthuis 1987). Give the seasoal ature of both distributio ad spawig patters i P. edwardsi, it is likely that the vertical movemets of the populatio could be related to reproductio. Most shrimps, particularly ovigerous females, ihabit shallower waters durig the secod half (July to September) of the mai spawig period. A similar patter has bee observed for P. arval off the Caary Islads (Gozález et al. 1997). These migratory ad reproductive patters become more difficult to iterpret whe aalysig the bathymetric distributio i relatio to shrimp legth. Off the Caary Islads, the size of female P. edwardsi appears to icrease with greater depth. A similar tred has bee reported for other padalids, e.g. P. arval, Padalus borealis, Padalus motagui, Heterocarpus laevigatus, Heterocarpus sibogae ad H. esifer, where larger idividuals occupy deeper waters (Thessalou-Legaki 1989, Gozález et al. 1997). I the preset study, P. edwardsi showed o size gradiet with depth i relatig to spawig seaso. No-retur migratios towards deeper waters are believed to be the reaso for such size differeces i the ishore/offshore distributio of padalids (Thessalou-Legaki et al. 1989). The observatio that female P. edwardsi are larger tha males ad that ovigerous females are larger tha o-ovigerous idividuals has bee reported for shrimps off the Seychelles (Itès ad Bach 1989) ad the Azores (Martis ad Hargreaves 1991). The predomiace of females i the large size-classes suggests that P. edwardsi might be a protadrous

1997 Sataa et al.: Life History of Plesioika edwardsi aroud Caary Islads 47 hermaphrodite, as has bee reported for may tropical ad temperate deep-water padalids, e.g. Padalus daae, Padalus jordai, P. borealis, H. esifer, H. laevigatus ad H. sibogae (Kig ad Moffitt 1984, Thessalou-Legaki et al. 1989). However, the results are ot coclusive. That females are larger tha males ad sex ratios favourig females i larger size-classes have traditioally bee used as evidece for sex reversal. However, similar variatios i size ad sex ratios ca occur i dioecious species where there are sex differeces i relatio to growth, mortality, migratio ad habitat preferece. Differeces i size ad sex ratios appear to have bee icorrectly used to support the hypothesis of sex reversal i other crustaceas (Kig ad Moffitt 1984). Growth parameters calculated i this study, particularly for females, are similar to those reported for P. edwardsi off the Fiji Islads (Kig 1986) ad the Seychelles (Itès ad Bach 1989). The preset data show marked differeces i growth patters betwee the sexes where females have higher growth rates tha males, which accouts for the observed patters of sizes ad sex ratios. Gozález et al. (1997) foud similar sex differeces i relatio to size, sex ratio ad growth patters i P. arval off the Caary Islads. The data preseted here regardig seasoal migratios, sex ratios ad growth suggest that P. edwardsi is dioecious. Therefore, the species coforms to the reproductive patter of tropical padalids ad demostrates the complex ature of their life history. ACKNOWLEDGEMENTS The assistace of our colleagues, Mr V. Rico ad Ms M. García, is gratefully ackowledged. Part of the study was carried out uder the auspices of the Commuity Research Programme, with fiacial support from the Europea Commissio. LITERATURE CITED BISCOITO, M. J. 1993 A accout of the shrimps of the family Padalidae (Crustacea, Decapoda, Caridea) i Madeira waters. Cour. Forsch.-Ist. Seckeberg 159: 321 325. CALDENTEY, M. 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