Abundance, Activity, and Trophic Patterns of the Redspotted Catshark, Schroederichthys Chilensis, on the Pacific Temperate Coast of Chile Author(S): Jose M

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Abundance, Activity, and Trophic Patterns of the Redspotted Catshark, Schroederichthys chilensis, on the Pacific Temperate Coast of Chile Author(s): Jose M. Fariña and F. Patricio Ojeda Source: Copeia, Vol. 1993, No. 2 (May 3, 1993), pp. 545-549 Published by: American Society of Ichthyologists and Herpetologists (ASIH) Stable URL: http://www.jstor.org/stable/1447159 Accessed: 12-12-2017 18:26 UTC

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This content downloaded from 146.155.28.60 on Tue, 12 Dec 2017 18:26:56 UTC All use subject to http://about.jstor.org/terms SHORTER CONTRIBUTIONS: ICHTHYOLOGY 545 port, A. Marconato for drawing the DOUGLAS figure, Y. andSHAPIRO, Department of Biology, D. Goulet and T. Liberman for reviews of the Eastern Michigan University, Ypsilanti, Michigan manuscript. 48197; and AMATZIA GENIN, Hebrew University of Jerusalem, H. Steinitz Marine Biology Labo- LITERATURE CITED ratory, P.O. Box 469, Eilat, Israel. Submitted 7 Feb. 1992. Accepted 19 May 1992. Section DE BOER, B. A. 1978. Factors influencing the distri- editor: W. J. Matthews. bution of the damselfish Chromis cyanea (Poey), Po- macentridae, on a reef at Curarao, Netherlands Antilles. Bull. Mar. Sci. 28:550-565. BRAY, R. N. 7981. Influence of water currents and zooplankton densities on daily foraging movements of blacksmith, Chromis punctipinnis, a planktivorous Copeia, 1993(2), pp. 545-549 reef fish. Fish. Bull. 78:829-841. @ 1993 by the American Society of Ichthyologists and Herpetologists DAVIS, W. P., AND R. S. BIRDSONG. 1,973. Coral reef fishes which -forage in the water column. Helgol. ABUNDANCE, ACTIVITY, AND TROPHIC Wiss. Meeresunters. 24:292-306.' PATTERNS OF THE REDSPOTTED CAT- HAMNER, W. M., M. S. JONES, J. H. CARLETON, I. R. SHARK, SCHROEDERICHTHYS CHILENSIS, HAURI, AND D. M. WILLIAMS. 1988. Zooplankton, ON THE PACIFIC TEMPERATE COAST OF planktivorous fish, and water currents on a wind- ward reef face: Great Barrier Reef, Australia; CHILE.-The Bull. redspotted catshark, Schroeder- Mar. Sci. 42-459-479. ichthys chilensis (Guichenot, 1848), is a common HoBsoN, E. S., ANDJ. R. CHESS. 1978. Trophic inshore re- shark that occurs from Anc6n (central lationships among fishes and plankton in the lagoonPerui) to Chilo6 (southern Chile) (Chirichigno, at Enewetak Atoll, Marshall Islands. Fish. Bull. 1974; 76: Compagno, 1984) at depths from 1-50 133-153. m (Mann, 1954). Despite this species being re- KINGSFORD, M. J., AND A. B. MACDIARMID. 1988. ported as one of the most abundant components Interrelationships between planktivorous reef fish and zooplankton in temperate waters. Mar. of Ecol. the nearshore fish assemblages in central and Prog. Ser. 48:103-117. southern Chilean waters (Bahamonde, 1952; POPPER, D., AND L. FISHELSON. 1973. Ecology Miranda, and 1967), little quantitative information behaviour of Anthias squamipinnis (Peters, has 1855) been gathered on basic aspects of its biology (Anthiidae, Teleostei) in the coral habitat ofand Eilat ecology. Based on a sample of 38 individuals (Red Sea). J. Exp. Zool--184:409-424. from southern Chile (Puerto Montt), Baha- SHAPIRO, D. Y. 1979. Social behavior, group mondestruc- (1952) reported a diet consisting pri- ture, and the control-of sex reversal in hermaph- marily of sipunculans. More recently, Miranda roditic fish. Adv. Study Behav. 10:43-102. (1980) reported a sexual aggregation of this spe- 1. 1980. Serial female sex changes after simul- cies occurring during autumn in a central Chil- taneous removal of males from social groups of a coral reef fish. Science 209:1136-1137. ean locality (San Antonio). In this paper, we -. 1986. Intragroup home ranges in a female- document information about abundance, activ- biased group of a sex-changing fish. Anim. Behav. ity, feeding, and reproductive patterns of the 34:865-870. redspotted catshark based on a two-year study - . 1988. Variation of group composition along and the central Chilean coast. Particular at- spatial structure with group size in a sex-changing tention is given to food habits in order to elu- fish. Ibid. 36:140-149. cidate the ecological role of this species in near- ---, AND R. H. BOULON, JR. 1987. Evenly shore dis- communities and its potential impact on persed social groups and intergroup competition important commercial benthic species currently for juveniles in a coral reef fish. Behav. Ecol. So- ciobiol. 21:343-350. being exploited by local artisanal fisheries. STEVENSON, R. A., JR. 1972. Regulation of feeding behavior of the bicolor damselfish (Eupomacentrus Materials and methods.--Redspotted catsharks, partitus Poey) by environmental factors, p.-S. chilensis,278- were collected at two localities on 302. In: Behavior of marine animals, volume the2: ver- central Chilean coast, Punta de Tralca tebrates. H. E. Winn and B. L. Olla (eds). Plenrum (33035'S; 71042'W) and Quintay (33011'S; Press, New York, New York. 71043'W). The substrate of the subtidal zone in VOGEL, S. 1981. Life in moving fluids. Willard Grant both sites consists of a sloping bedrock with Press, Boston, Massachusetts. large rocks and boulders in its shallower portion YoGO, Y. 1986. Protogyny, reproductive behavior and social structure of the Anthiine fish Anthias (0-6 m depth), with an increasing proportion (Franzia) squamipinnis, p. 964. In: Indo-Pacific fishof sand in its deeper portion (6-18 m depth). biology. T. Uyeno, R. Arai, T. Taniuchi, and Large K. plants of the brown kelp, Lessonia trabecu- Matsuura (eds.). The Ichthyological Society ofJa- lata, form an extensive bed extending from 3- pan, Tokyo. 4 m to about 16 m depth. The catsharks were

This content downloaded from 146.155.28.60 on Tue, 12 Dec 2017 18:26:56 UTC All use subject to http://about.jstor.org/terms 546 COPEIA, 1993, NO. 2

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FALL WINTER SPRING SUMMER FALL WINTER SPRING 1989 1990 Fig. 1. Seasonal 3-. variation WINTER of the relative abundance (CPUE) of redspotted catsharks off the central Chilean coast captured during 1989-90. ND = no 2 data.

seasonally sampled from May 1989 to Nov. 1990, except in fall 1990, with three 3 x 30 m experimental gillnets consisting of five panels (graded in mesh size from 10-50 mm) that were randomly set in 14, parallel SPRING on the bottom perpen- dicular to the coastline at depths between 5 and

20 m. These gillnets 10 were usually set within the first hour after sunrise and retrieved one hour before sunset. After all fish were removed, the nets were set again overnight and retrieved in the morning. All specimens captured were sexed, measured (TL) to the nearest mm, and 2 weighed to the nearest 1.0 g. Their stomachs, ra0 . intestines, and gonads were removed and fixed in a 5-10% solution of buffered formalin-sea- water mixture, placed in labeled plastic bags, S and transported to the laboratory for further 10 analysis. In the laboratory, the oviducts were inter- nally inspected for presence or absence of en- z capsulated eggs. The diet was estimated from gut contents. Prey items from each stomach were 2 identified to the finest taxonomic resolution, counted, measured and wet-weighed to the 40 45 50 55 60 65 70 nearest g. The importance of each prey species T ot al L e n g t h (cm) was evaluated by calculating an index of relative importance (IRI; Pinkas et al., 1971), as follows: Fig. 2. Seasonal size frequency distributions of IRI = (n + W) FO, where n = percentage nu- redspotted catsharks off the central Chilean coast captured during 1989-90. merical composition, W = percentage gravi- metric composition, and FO = percentage frequency of occurrence. Abundance patterns of this species were de- X2 test for goodness of fit, P < 0.001) suggesting termined by using a catch-per-unit-effort that this species is primarily crepuscular and/ (CPUE) measurement. This index was calculat- or nocturnal. ed as the total number of specimens captured The abundance of this species (expressed as in the nets divided by the total number of sam- CPUE) showed a clear seasonal pattern (Fig. 1) pling hours during each season. with maximum values of about 0.37 individuals per hour during fall, minimum values (~0.11) Results. -A total of 214 specimens of S. chilensis during winter, and intermediate values during ranging in size from 41-66 cm in TL was cap- spring and summer. A significantly greater tured during this study; 157 in Punta de Tralca number of females (n = 144) than of males (n and 57 in Quintay. Most of these specimens = 65) was collected throughout study (x2 = 29.9, were caught during the night (190 versus 24; P < 0.01). Seasonal frequency distributions of

This content downloaded from 146.155.28.60 on Tue, 12 Dec 2017 18:26:56 UTC All use subject to http://about.jstor.org/terms SHORTER CONTRIBUTIONS: ICHTHYOLOGY 547 body sizes showed a general increase 80- from fall to summer (Fig. 2). This trend was mainly due to a significant increase of female 60- size from fall to summer (One-way ANOVA; F = 17.0, P < 0.001). No seasonal differences S 40in mean body Lw size were detected among males e 20 - (Fig. 2). No specimens smaller than 41 cm in TL were caught during this study (see Fig. 2). FALL WINTER SPRING SUMNMER FALL WINTER SPRING Reproductive females (i.e., with encapsulated 1989 1990 eggs) were observed year-round in our samples (Fig. 3). Their presence, however, Fig. was 3. some- Seasonal variation of the relative abun- what seasonal, being rare during dance fall of(percentage) 1989 of ovigerous female catsharks captured off the central Chilean coast during 1989-90. (less than 5% of total captured ND = nofemales), data. in- creasingly frequent from winter to spring (>45%), and reaching values of 65% during summer (Fig. 3). Most of the femaleswater movement had one and turbulence typical of this or two eggs of about 20-30 mm zone in during diameter. this season. Of the 214 catsharks captured, Breeding 13 (6.1%) and had oviposition seem to occur an empty stomach. The remains throughout of about the year 16 in an annual cycle. The prey taxa were observed in the paucity other of stomachsovigerous females during fall prob- (Table 1). Because no significant ably differences indicates that ineggs were laid during sum- dietary composition were detected mer, when between massive the depositions of egg-cases oc- catsharks from Quintay and curred Punta on defronds Tralca of the subtidal brown kelp (Kendall Coefficient of Concordance, Lessonia (Vasquez,W = 0.68, 1989; pers. obs.). This type P < 0.001; Siegel and Castellan, of reproductive1988), trophic strategy has been also docu- data were pooled for analysis. mented Decapod for other crus- Scyliorhinids (Springer, 1979; taceans were the most important Compagno, prey 1984; (IRI Able = and Flescher, 1991), and 15029), being found in over 85% it seems of the to be stom- a common feature of bottom- achs examined and representing dwelling more thansharks 85% (Stevens and McLoughlin, of the total number of prey and 1991). of total prey weight (Table 1). Most of the population of catsharks consisted Rock shrimp (Rhynchocinetes typus) of large-sized was adultthe individuals most (see Fig. 3). The important crustacean prey absence(IRI of= juveniles 778; or Table small-sized individuals 1). Crabs, primarily Allopetrolisthes (less than punctatus, 40 cm TL) documented Pe- in this study trolisthes violaceus, Cancer edwardsi, as well as by and Miranda Homa- (1980) and George-Nas- laspis plana, were also important cimento prey and Vergara items (1982), ofsuggests that re- catsharks (Table 1). Several centlyother hatched species catsharks migrate of into deeper crustaceans, polychaetes, fishes, waters. and The causesalgal of thisma- particular migration terial also formed part of the pattern catshark's are unknown diet, but may well represent a but, in general, they were of minorpredator avoidance importance mechanism, given that the (Table 1). No significant seasonal sublittoral differences zone is occupied by a varied suite of were observed in the diet predatory of this species species along this coast (Miranda, throughout this study (Kendall 1967; Coefficient Moreno et al., 1979; ofpers. obs.). This phe- Concordance, W = 0.47, P < nomenon,0.05). characterized Decapods by a clear spatial seg- (several species) represented more regation than between 75% juvenile of and adult popula- total prey weight during all seasons. tions, may constituteOther a preygeneral pattern among items such as polychaetes, fish, Scyliorhinids and gastropod (Castro et al., 1988), because it has mollusks were also preyed throughout been documented the foryear other elasmobranchs with different intensity, most (Garcia, likely 1984). as a result of seasonal changes in their availability. Gut content analysis and the abundance pattern of S. chilensis indicate that (1) this species Discussion.--Our results suggest is anthat important the predatorrocky in the rocky subtidal sublittoral zone is utilized by zone redspotted along the central cat- coast of Chile as previ- sharks for feeding and reproductive ously suggested purposes. by Moreno et al. (1979); (2) this Although catsharks were present is a specialized year-round, predator on crustacean deca- the minimum abundance observed pods; and during (3) its diet win- is quite conservative, be- ter suggests an offshore migration cause no changesinto deeper were detected either season- waters probably as a consequence ally or of spatially. the strongImportant prey items for this

This content downloaded from 146.155.28.60 on Tue, 12 Dec 2017 18:26:56 UTC All use subject to http://about.jstor.org/terms 548 COPEIA, 1993, NO. 2

TABLE 1. DIET COMPOSITION OF Schroederichthys chilensis EXPRESSED AS NUMBER OF INDIVIDUALS (n), PER- CENTAGE OF TOTAL n (%), FREQUENCY OF OCCURRENCE (FO), PERCENTAGE OF FO (%), WEIGHT IN g (W), PERCENTAGE OF TOTAL WEIGHT (%), AND WITH THE INDEX OF RELATIVE IMPORTANCE (IRI).

Prey n (%) FO (%) W (%) IRI

Mollusks Gastropods 3 (1.6) 3 (1.6) 7.0 (1.6) 5 Polychaetes 9 (4.8) 8 (4.2) 9.8 (2.2) 29 Crustaceans Decapods Rhynchocinetes typus 39 (20.7) 37 (19.6) 84.1 (19.0) 778 Allopetrolisthes punctatus 20 (10.6) 19 (10.1) 74.4 (16.8) 277 Cancer edwardsi 9 (4.8) 8 (4.2) 34.4 (7.8) 53 Petrolisthes violaceus 16 (8.5) 15 (7.9) 61.1 (13.8) 176 Taliepus dentatus 9 (4.8) 7 (3.7) 23.2 (5.2) 37 Homalaspis plana 7 (3.7) 7 (3.7) 38.5 (8.7) 46 Pilumnoides perlatus 3 (1.6) 3 (1.6) 4.3 (1.0) 4 Pinnixa chiloensis 2 (1.1) 2 (1.1) 0.6 (0.1) 1 Paraxanthus barbiger 3 (1.6) 3 (1.6) 5.2 (1.2) 4 Synalpheus spinifrons 1 (0.5) 1 (0.5) 0.8 (0.2) <1 Crab remains 59 (31.4) 59 (31.2) 58.5 (13.2) 1392 Total 168 (89.3) 161 (85.2) 385.2 (87.1) 15,029 Fishes Remains 8 (4.3) 8 (4.2) 36.3 (8.2) 53 Algae 9 (4.8) 4.1 (0.9)

catshark are Generallyrock speaking, ourshrimp results on the diet of and several crab species, which havethe redspotted catshark been in the central reported Chilean as common in- habitants of coastsubtidal are somewhat comparable rocky to those re- shores dominated by large kelps (Antezana ported for other small-sized inshore sharkset such al., 1965; Villouta and Santelices, 1984), as some dogfishes and (Lyle, 1983; which Compagno, are important fish- ery resources 1984). Despitealong local variability the in the compo- Chilean coast (Lorenzen et al., 1979; sition Vaisquez of the associated benthic communities, and Castilla, 1982). The abundance of benthic invertebrates at these lo- Scyliorhinids seem to have developed common calities measured over the same study period (F. feeding strategies. Whether this shared con- P. Ojeda and W. Ciceres, unpubl.), suggest that sumption of crustaceans involves a maximiza- these crustacean species are preferentially con- tion of caloric intake or differences in relative sumed among a large array of potential and prey abundance is a question that needs further abundant invertebrate prey in rocky subtidal research. shores. The specialized diet, primarily based on crustacean decapods, is probably related to the Acknowledgments. -We thank G. Benavides, W. feeding behavior of catsharks. They are mostly Caiceres, P. Camus, L. Fuentes, A. Palma, E. nocturnal predators, forming large resting ag- Varas, and P. Zavala for important assistance gregations in crevices and caverns during the in the field. F. Jaksic, M. George-Nascimento, day (pers. obs.). Crustacean prey such as crabs and R. Steneck provided helpful comments on and rock shrimps were more active and abun- the manuscript. This research was supported by dant at night than during daytime, which may a FONDECYT grant (No. 0349-89) to FPO. explain their dominance in the catshark's diet. Decapod species have been shown to contain the highest caloric contents (per gram of live LITERATURE CITED mass) among a large suite of benthic inverte- ABLE, K. W., AND D. FLESCHER. 1991. Distribution brates inhabiting the Chilean coast (Duarte et and habitat of Chain Dogfish, Scyliorhinus retifer, in al., 1980; see also Ojeda and Dearborn, 1991). the Mid-Atlantic Bight. Copeia 1991:231-234. Accordingly, it is possible that the specialized ANTEZANA, T., E. FAGETTI, AND M. T. LOPEZ. 1965. diet observed in this catshark reflects a feeding Observaciones bioecol6gicas en Decaipodos co- strategy based on a maximization of energy in- munes de Valparaiso. Rev. Biol. Mar., Valparaiso take. 12:1-15.

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BAHAMONDE, N. 1952. Alimentaci6n tribution,de la Pintarroja size and sex composition, reproductive (Halaelurus chilensis (Guichenot), 1948).biology andInv. diet Zool. of sharks from Northern Australia. Chilenas 1:3-5. Aust. J. Mar. Freshwater Res. 42:151-199. CASTRO,J. I., P. M. BUBUCIS, AND N. A. OVERSTROM. VASQUEZ, J. A. 1989. Estructura y organizacion de 1988. The reproductive biology of the Chain huirales Dog- submareales de Lessonia trabeculata. Un- fish, Scyliorhinus retifer. Copeia 1988:740-746. publ. Ph.D. diss., Univ. de Chile, Santiago, Chile. CHIRICHIGNO, N. 1974. Clave para identificar los peces , AND J. C. CASTILLA. 1982. Areas de reclu- marinos del Peru. Informe Instituto del Mar del tamiento y estructura poblacional de Rhynchocinetes Perui, Callao 44:1-387. typus Milne Edwards, 1837 (Crustacea: Rhyncho- COMPAGNO, L. J. V. 1984. FAO species catalogue. cinetidae), en Chile central. Inv. Mar. Valparaiso Vol. 4. Sharks of the world. 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