Rev. Biol. Trop., 44(2): 803-811,1996

Trophic comparison among Triglidae (Pisces: Scorpaeniformes) off Baja California Sur, Mexico

Juan Jacobo Schmitter-Sotol and José Luis Castro-Aguirre2 I Depto. de Ecología Acuática, Centro de Investigaciones de Quintana Roo. A.p. 424,MEX-77000 Chetumal, Q.R., México. Div. de Biología Marina, Centro de Investigaciones Biológicas del Noroeste. A.p. 128, MEX-23001 La Paz, B.C.S., México.

(Rec. I7-X-1994. Rev. 17-IV-1995. Accep. 16-VI-1995)

Abstract: Composition, intensity, diversity, ontogenetic and seasonal changes of feeding of Prionotus stephanophrys, Bellator gymnostethus and P. albirostris were studied in the Pacific coast of Baja California Sur, Mexico. A total of 547 individuals of the three species were sampled between 1988 and 1990. The euphausiid Nyctiphanes simplex was the main prey of B.gymnostethus, which caught it during the day, and of P. stephanophrys, which ate it at night and twilight; latger individuals of P. stephanophrys shifted to Pleuroncodes planipes, a change that coincided with (he fish' shift from the pelagic to the benthic environment. Feeding intensity of this searobin was higher in summer, after reproduction. P. albirostris fed throughout the day; its diet, more diverse and equitable, was based on penaeids, pasiphaeids, and mysids. Differences in spatial distribution, diet and time of feeding suggested efficient habitat parti­ tioning among these fishes,

Key words: Triglidae, Prionotus stephanophrys, Bellator gymnostethus, Prionotus albirostris, food habits, habitat pat­ titioning, Eastern Pacifico

Searobins (Triglidae), known in Mexico as This, together with its much greater size (and, triglas or vaquitas and in South America as presumably, different diet), separates it from vocadores or cabrinhas, are benthic fishes the other species. Sediment type distinguishes inhabiting tropical and subtropical continental B. xenisma and B. loxias, which appear to be shelves worldwide, such as the outer (western) more frequent over sand, from the others, coast uf Baja California Sur, Mexico. Six which occur more often over silt. As muddy triglid species are found in this area: Prionotus bottoms are the rule in this area, it is not sur­ stephanophrys Lockington (overwhelmingly prising that these Bellator species are scarce dominant), P. albirostris Jordan & Bollman, (Schmitter-Soto 1992). Bellator gymnostethus (Gilbert), P. ruscarius Autoecological aspects of Triglidae in the Gilbert & Starks, B. xenisma (Jordan & Eastern Pacific have not received much atten­ Bollman) and B. loxias (Jordan), the last three tion. Samamé et al. (1983) and Meléndez being occasional. Their bathymetric distribu­ (1987) offered sorne trophic data on tion overlaps broadly. P. stephanophrys occurs P. stephanophrys from Peru and Chile, respec­ throughout the explored latitudinal range; it tively; the Peruvian study discussed also distri­ was the only triglid collected as far north as the bution and reproduction. Schmitter-Soto & Bay of Sebastián Vizcaíno (Schmitter-Soto Castro-Aguirre (1991, 1994) examined age and 1992). growth of P. stephanophrys, B. gymnostethus Though abundances of the six species and P. albirostris. increase off the mouths of the Magdalena­ This work analyzes and compares diet com­ Almejas Lagoon Complex (ca. 24°30'N), only position, intensity and diversity, as well as P. ruscarius has been found inside the lagoons. ontogenetic, diel and seasonal trophic changes, 804 REVISTA DE BIOLOGIA TROPICAL for P. stephanophrys, B. gymnostethus and P. mateJy 30 stomachs the curve almost reached albirostris. The results will aid in a discus­ an asymptote. sion of habitat partitioning among these When possible, we processed samples on searobins. board; if not, we injected 5% formaldehyde neutralized with seawater ¡nto stomach and coelom. We studied stomach contents on a MATERIAL AND METHODS Petri dish with 70% ethanol. To cast light on feeding rhythms, we c1assi­ The analyzed fishes carne from 50 diurnal fied digestion stages as follows: 1, contents and nocturnal samples, taken off the western mostly intact, identifiable; 2, contents mostly coast of the southern half of the Baja California not recognizable (fragments); 3, amorphous Peninsula, from the Bay of Sebastián Vizcaíno contents; O, no contents. We included empty (29°N, 115°W) to the southern tip of the stomachs in this scale, considering vacuity a Magdalena-Almejas Lagoon Complex (24°N, step that c10ses the cycle. 111°W), in depths from 20 to 240 m. We estab­ In stomachs in digestion stage 1 or 2, we lished the sampling stations on muddy or sandy identified prey items to the lowest possible bottoms, suitable for the operation of the fish­ taxon under a stereomicroscope, with the help ing gear (trawl nets, 21 m wide at the opening, of the pertinent literature. We counted the num­ 24 m long, 3 cm mesh), during five cruises on ber of individuals, and measured the volume by board the RN "El Puma", from 1988 to 1990 displacement to the nearest 0.1 mI; excessive (Table 1); mean trawl duration was 20 min, at a alcohol was previously blotted out. speed of 3 knots. The index of relative importance, IRI We separated the triglíds from the total (Pinkas el al. 1971), has been criticized catch, and took a stratified sample of because of its supposedly questionable biologi­ P. stephanophrys; since B. gymnostethus and P. cal significance. Nevertheless, we chose it albirostris were scarce, we collected aH avail­ because it is a practica! measure of trophic able individuals, but still could not perform importance, which incorporates the relative quantítative seasonal and ontogenetic analysis number of organisms (N%), relevant in forag­ of these two species. Furthermore, length varia­ ing theory, and the percent volume (V%), a tion was very Jow in sorne seasons (Table 1), probable reflection of caloric content (Wallace indicating bias towards the few size c1asses 1981, Moreno i Amich 1987). present in the habitat at that time. However, the We analyzed diet changes of P. samples were suitable for interspecific compar­ stephanophrys by season, time of day and size. isons, as determined by plotting cumulative For that purpose, the winter sample consisted trophic diversity VS. cumulative number of of the cruises of February 1989 and March stomachs examined (Pielou 1966): at approxi- 1990, and summer included July 1989 and

TABLE 1

Collection data of Triglidae fmm the westerncoast of Baja California Sur

P. step/wnophrys B. gymnostethus P. albirostris

Cruise N L N L N L Depth Latitude (mm) (mm) (mm) (m) (oN)

Oct 88 4 108±19 9 J37±70 32-145 24.2-26.1 Feb 89 13 1l0±50 27-135 24.3-26.3 Jul 89 170 135±36 21 102±13 10 183±9 31-143 25.1-28.6 Mar 90 138 140±53 30 91±27 16 180±1O 36-241 24.2-28.8 Sep 90 131 160±43 15 176±30 38-218 24.1-28.8

Total 452 SS 50

N, samp1e size (number of stomachs); L, mean standard length of físh (± 1 SD). SCHMITTER-SOTO & CASTRO-AGUIRRE: Trophic comparison among Triglidae 805

September 1990. The day was divided into dawn (0501-0700 h), day (0701-1700), sunset F'J!. r 10% (1701-1900) and níght (1901-0500). We did not a priori assígn size categories of P. stephanophrys, but sought an abrupt change in consumption of the main prey. To do this, we examined curves of item frequency vs. standard Jength (SL) of the fish. Non-parametric comparisons of feeding composition and intensity involved ranking food items according to their IRI values, to compare trophic spectra between seasons or N� 80 60 40 20 10 o 2 10.1'1 OZ(\I sizes, and digestion stages according to their percent occurrence, to compare intensity by Fíg. 1. Main prey of Prionotus stephanophrys off Baja California Sur. Rectangle area reflects prey ¡mportance as season or time of day. measured by percent volume (V%), percent abundance To carry out a similarity analysis between (N%) and percent occurrence (F%). Horizontal scales are specific diets we used Whittaker' s PSI on prey logarithmic. items whose IRI 2::0.1%. This measure of diet overlap is reputedly advantageous because of other items were occasional, including cope­ its independence from sample size (Kohn & Riggs 1982), and Wallace (1981) recommends pods, mysids, gammarideans, stomatopods, it when data on prey availability are insuffi­ carídeans, penaeids and fishes, among others cient or absent; trophic spectra are considered (complete data are available from the first author). significantIy similar when PSI> 60%. To further describe prey communities we The sample of B. gymnostethus consisted of obtained diversity, richness, and equitability 55 stomachs (Table 1). Among the 18 prey indices (Pielou 1966, Margalef 1980); these ¡tems, N. simplex was again dominant, fol­ lowed by fish larvae and the penaeid shrimp indices, usually applied on N% or V%, were Sicyonia ingentis (Fig. 2). Gammarideans, applied here on the feeding coefficíent (Q = copepods, mysids, and carideans figured N%+V%, in Braga & Braga 1987). Thus, for example, diversity was determined as among the other items.

S F14 110 L HQ = - Q%¡lnQ%¡ ¡=l I TOlo,,".' lIor,,"1 1 where S is the total number of food cate­ N)'#'ph.�, ".,,,. gories and Q%¡ is the feeding coefficíent of the Í-th species, expressed as percentage of the M eaI 00 40 EO 10 a ! I o.ao..eo..IO.OIIO-00OJQ.2o.a I2 6 10 1:0 40I GO 80 V1f, sumatory of Q for all food categories. Braga & Braga (1987) used to c1assify prey items as Fig. 2. Main prey of Bellator gymnostethus off Baja Q CaliforniaSur. See Fig. l. "preferential" (Q > 200), "secondary" (20 < Q < 200) or "accidental" (Q < 20).

The sample of P. albirostris consisted of RESULTS 50 stomachs (Table 1). The global trophic spectrum included 22 food ¡tems. The Trophic spectra: The sample of P. penaeíd Solenocera mutator was preferred, stephanophrys consisted of 452 stomachs followed by pasiphaeid Leptochela serrator­ (Table 1). The global trophic spectrum com­ bita and mysids (Fig. 3). Less important prised 35 prey categories. The euphausiid items included gammarideans, the stomato­ Nyctiphanes simplex was clearly domínant (Q pod Hemisquilla ensigera. carideans other » 200), followed secondarily (Q > 20) by the than L. serratorbita, S. ingentis, pinnotherids, red crab Pleuroncodes planipes (Fig. 1). AH portunids and fishes. 806 REVISTA DE BIOLOGIA TROPICAL

C�rcadian variation of feeding intensity: l� wmter, P. stephanophrys stomachs in diges­ hon stages 2 and 1 were more abundant during the light hours and digestion stage 3 occurred mote :often after sl1nset. Vacuity had 10wer val­

"'" eoOQ 40 20 10 a 2 1660.20Jo.OOQQ60Io.2o.ef 2 It 10 20 4(1 &0&0 VU ues as the hours passed, with most empty stom­ achs al dawn (Table 2). Thus, food was ingest­ Fig. 3. Main prey of Prionotus albirostris off Baja ed mainly during the day, as happened in the California Sur. See Fig. J. other species, though the tendency was not cIear enough to be statisticalIy significant (Friedman's c2). Diet diversity:Though the diet of P. different pattern appeared in summer, stephanophrys was the richest (DQ = 4.22), it A when the maximum number of intact prey was the least diverse (H = 0.14), due to the Q occurred at and after sunset, and stomachs in enormous numbers of N. slmplex, which lowered advanced digestion prevailed earlier in the day, equitability to 0.04. A partial reason for the richness of this trophic spectrum was the bathy­ while vacuity was higher towards sunset (Table 2). metric and latitudinal ubiquity of the species, This circadian feeding rhythm change was 2 = 7.82, < 0.05). which enabled it to prey on oroanisms from significant in summer (c P The seasonal change is discussed below. different zones. Thus, for instan�e, Mysis sp., Palaemonidae and Copepoda appeared only off Regardless of season, predation on the two the mouths of the Magdalena-Almejas Lagoon main prey categories, N. simplex and P. pla­ Complex; Stomatopoda were found no deeper nipes, had distinct patterns: the searobin ate the euphausiid almost exclusively at night, whereas than 100 m, but Hemisquilla ensigera south the red crab was eaten mostly at sunset (Fig. and Schmittius polita north of parallel 26°N; 4). The vacuity of B. gymnostethus stomachs the genus Sicyonia was circumscribed to the decreased from dawn to night; the opposite Bay of Sebastián Vizcaíno, but S. penicillata in happened with stomachs in digestion stage shallower and S. ingentis in deeper waters. 3 (Table 3). This indicated that gymnostethus B. gymnostethus had the least equitable (JQ B. feeds during the day, like P. stephanophrys in = 0.01) and poorest (DQ = 2.09) trophic spec­ trum; yet, paradoxicaIly, its diversity was com­ winter. However, as most fish were captured only from 0800 to 1700 h, the tendency was paratively high (HO = 0.19). The relatively ñigh diversity of the prey not significant. Although al! P. albirostris empty stomachs community of P. albirostris (H = 0.21). was Q appeared at sunset, and the greatest amounts of due more to equitability = 0.07) than to (JQ digested food concentrated towards midday, richness (DQ = 2.37).

TABLE 2

Círcadian variafion offeeding intensity in Prionotus stephanophrys by season offBaja CaliforniaSur. Figures are perc'ent frequency by ume (1day; digestion stages are explained in tex!

Down Day Sunset Night 0501-0700 0701-1700 1701-1900 1901-0500 Digestion state Win Summ Win Summ Win Summ Win Summ

o 36 3 26 11 17 10 10 o 1 9 22 21 15 O 45 17 41 2 50 31 47 41 8 23 17 18 3 5 44 6 33 75 23 57 41

Win, winter: Summ, summer. SCHMITTER-SOTO & CASTRO-AGUIRRE: Trophic comparison among Triglidae 807

TABLE 3

Circadian variarion of feeding intensity in Bellator gymnostethus and Prionotus albirostris offBaja California Sur. Figures are percent frequency by time of day; digestion stages are explained in texto No specimens ({P. albirostris were captured at night (]901-0500 h)

Digestion Dawn Doy Sunset Night stage 0501-0700 0701-1700 1701-1900 1901-0500

Bellator gymnostethus O 100 14 10 O I O 23 10 O 2 O 49 30 50 3 O 14 50 50

Prionotus albirostris O O O 23 I 38 33 31 2 62 34 38 3 O 33 8

Ontogenetic changes: Two size categories of P. stephanophrys were establíshed, below and aboye 133 mm SL, the median SL. This length coincided with a rather sharp shift in prey preference, from N. simplex to the red crab (Fig. 5). Similarly, other smaIl prey, such as gammarideans, were more abundant in small searobins; the opposite happened with larger prey, such as fishes (Fíg. 6). Study of ontogenetic trophic changes in species other than P. stephanophrys was not Fig. 4. Circadian variation of the consumption of Nyctipha­ possible, because of the small sample sizes. nes simplex and Pleuroncodes planipes by Priono!Us step­ hanophrys off Baja California Sur. Similarity analysis: The trophic spectra of P. stephanophrys and B. gymnostethus were significantly similar (PSI> 80%); P. albirostris íntact food could be found from dawn till sun­ diet was different from that of the other set (Table 3). We díd not capture the species at searobins. night.

Seasonal changes: Feeding íntensity of P. DISCUSSION stephanophrys increased in summer (Table 2; 2 c = 61.8, P < 0.001); so did diet diversity, Hahitat partitioning: From the viewpoint richness and equitabilíty. Diet composition was of dietary diversity, P. stephanophrys and 2 significantly different between seasons (c = B. gymnostethus tend to stenophagy, with a 53.1, P < 0.001). Nevertheless, the change was high diet overIap. Competition is avoided, in more quantitative than qualitative. N. simplex the first place, by the difference in mouth size and the red crab predominated in both summer that allows P. stephanophrys to prey on items and winter. Físhes were more important in inaccesible to B. gymnostethus, mainly on the summer; in winter, gammarideans were in third red crab P. planipes. place. Competition for N. simplex between B. gym­ Sample síze did not allow ínterseasonal nostethus and small P. stephanophrys is dimin­ analysis of B. gymnostethus or P. albirostris. ished by the dífferent time of predation: at 808 REVISTA DE BIOLOGIA TROPICAL

night by the latter species, during the day by Nyctiphanes simplex the former. Feeding time is a habitat partition factor as important as the trophic spectrum itself (Ross 1978, Teixeira & Haimovici 1989). The fact that the euphausíid and the red crab

50 are the most abundant and frequent non-infau­ nal invertebrates in the area (Brinton 1967a, Alvariño 1976) shows that P. stephanophrys 25 and B. gymnostethus are opportunistic carni­ vores, feeding on the most readily available prey. lardas & Zupanoviá (1983) reached the

50 100 I�O 200 �o mm same conclusion regarding Trigla lyra in the Adriatic. P. albirostris might also be labeled an 0/. Pleuroncodes planipes opportunistic carnivore, though S. mutator, a crucial food ítem, is not among the most abun­

75 dant members of the community. Its diet is less 1/ 1/ stenophagous, more diverse and equitable, and >­ I u z the fish seemingly feeds all day long. It does 50 O� appear to avoid, however,competing with ... 1) '" \ P. stephanophrys and gymnostethus for N. .... 1/ i B. simplex and P. planipes, given the rarity of 25 v these organisms in its trophic spectrum. 11\ 1\ The intensificatíon of feeding that P. stephanophrys shows in summer takes place 100 150 200 250 mm after the main reproductive pulse (Schmitter­ Soto 1992). Thís seems to be a common phe­ FISH LENGTH nomenon (Moreno & Matallanas 1983, Fig. 5. Ontogenetic diet change in Prionofus Teixeira & Haimovici 1989), understandable in stephanophrys off Baja California Sur. Bars are 95% con­ terms of higher energy needs. fidence intervals. A scheme of ecological partitioning among Triglidae in the western coast of Baja California Sur is proposed (Fig. 7): P. ruscar­ ius, B. xenísma and B. loxías are separated mainly by spatial factors, such as distribution,

mm SI.. sediment and temperature (Schmitter-Soto 0 diet > time. Are these observed patterns the effect of, or are they the cause that lessens, interspecific competition? Although quantitative data on resource availability are wanting, it seems clear N. slm¡;lex Amplllpoda P. pllHl!P(l$ Te' e o s te i that the main resources searobins are "compet­ ing" for (space on muddy bottoms, P. planipes, Fig. 6. Consumption of main prey by the two size c1asses of N. simplex) are not limited, but abundant. Qne Prionotus stephanophrysoff Baja California Sur. might speculate that such partitioning patterns SCHMITTER-SOTO & CASTRO-AGUIRRE: Trophic cornparison arnong Triglidae 809

...------the proportion of ophiuroids íts diet is much !I Prionol... _f oll.. in higher in Greek gulfs than at the other end of the Mediterranean. These geographical changes in selectivity [Bel lotor '001... 0 � might be ethological side-effects of an evolu­ SA"" T S; 1!I'e tionary divergence. There are indeed morpho­ BoIlator Io.i.. 11 II logical differences, proposed as subspecific, between South and North American P. stephanophrys (Neira et al. 1981).

Ontogenetic niche shift: The main prey of 1- UJ P. stephanophrys, the red crab and N. simplex, Ci are diel vertical migrators. The euphausiid migrates upward at night; during the day it is found mostly at depths of 150 m (Brinton

Fig. 7. Scherne of habitat partiotioning arnong Triglidae in 1967b). P. planipes is pelagic when its cara­ the western coast of Baja California Sur. pace is less than 17 mm long (Longhurst 1967); after reaching 32 mm, it becomes strict­ ly benthic (Alvariño 1976). The population between those sizes migrates upward at night, are relicts of a time when resources were as does the euphausiid. indeed limited (the "ghost of competitíon It can be hypothesized that the red crab past"). An alternative hypothesis is that differ­ becomes vulnerable at sunset, when migration entiation in resource use is a by-product of the starts and the crustaceans leave their refuges at speciation process, as the selectivity differ­ the bottom. Most of the individuals eaten ences between Peruvian and Mexican P. belong to the migrating part of the population, stephanophrys would illustrate (see below). and predation is more intense at those hours. On the other hand, predation on the Geographical changes in selectivity: AH euphausiid is more intense at night, when the studied Triglidae feed on epibenthos and ben­ greater part of the population is up in the thopelagic zooplankton; infauna is very sec­ water column. Moreover, sorne pelagic red ondary. The most abundant organisms in the crabs, shorter than 17 mm, were ingested. local infauna are polychaetes (de León These facts can be explained by the ontoge­ González 1990), but this does not affect the netic habitat shift of P. stephanophrys and diets of these fishes. other triglids. A similar situation exists in southern Brazil, In Baja California Sur, older individuals of where the "cabrinhas" seem to ignore the abun­ P. stephanophrys sporadically catch very dant annelids. P. nudigula and P. punctatus mobile species and benthopelagic organisms, practically do not inelude infauna in their diets but they feed essentially on epibenthos. It is the (Teíxeira & Haimovici 1989). younger fish that prey more on zooplankton. In Chile, P. stephanophrys feeds on gam­ Schmitter-Soto (1989) found that immature marideans, small shrimps and the galatheid searobins (mean standard length, 80 mm) Pleuroncodes monodon (Meléndez 1987), the swam in the water column at the same time and ecological equivalent to its Californian dieto place as 140-mm-SL adults could be captured The trophic spectrum of this searobin from the bottom. Hureau (1986) reported that changes in Peru. Samamé et al. (1983) found European triglids descend to shallow bottoms 63 % euphausiids (N%), but a much greater after a pelagic pre-adult stage. It is thus quite amount of Polychaeta. This difference in infau­ probable that at least part of the euphausiid nal comsumption between Peruvian and north­ biomass was captured in the water column, as ern Mexican Prionotus stephanophrys seems the smallest pelagic red crabs certainly were. comparable to the contrasting finds of Moreno i Amich (1988) established that Papaconstantinou (1982) and Moreno & migrating prey tend to be less frequent as the Matallanas (1983) on Lepidotrigla cavillone: predator grows, while benthic organisms 810 REVISTA DE BIOLOGIA TROPICAL

increase their occurrence. Ross (1978) detected cambiaron al galateido Pleuroncodes planipes, lo cual a shift from epifauna in the diet of young coincidió con el paso del pez del medio pelágico al béntico. La intensidad de alimentación de este tríg!ido fue mayor en P. scitulus to infauna in the adults, that is, a verano, después de ia reproducción. P. albirosfris se ali­ greater use of the substrate. The trophic separa­ mentó dUrante todo el día; su dieta, más diversa y equitati­ tíon corresponded to the transition size between va, se basó en peneidos, pasifeidos y mísidos. Lasdiferen­ immature and mature fishes, as happened here. cias en distribución, dieta y hora de alimentación indicaron However, the change was qualitative, while un eficiente reparto de hábitat. other authors (Moreno y Matallanas 1983, Braga & Braga 1987, this study) found that it was rather quantitative. An explanation can be REFERENCES found in the bathymetric spans covered. While Alvariño, A. 1976. Distribución batimétrica de the mentioned P. scitulus dwells in shallow Pleuroncodes planipes Stimpson (Crustáceo; bottoms no more than 10m deep, other species Galateido). Mem. Simp. BioI. Dinám. PobI. occupy sizeable portions of the shelf; thus, P. Camarones, Guaymas,Mexico: 264-285. scitulus would be forced to sharpen ontogenetic Braga, F.M. de S. & M.A.A. de S. Braga. 1987. Estudo trophic changes in order to reduce intraspecific do hábito alimentar de Prianotus punctatus (Bloch, competitíon (Ross 1978). 1797) (Teleostei, Triglidae), na regiao da I1ha According to Moreno i Amich (1988), major Anchieta, Estado de Sao Paulo, Brasil. Rev. Bras. diet changes are due to recruitment and matur­ Biol. 47:31-36. ing. Ross (1978) found that the main diet Brinton, E. 1967a. Distributional atlas of Euphausiacea change was preceded by an increase in mouth (Crustacea) in the California Current region. Part J. width and intestinal length, and followed by Calif. Coop. Oceanic Fish. Invest., Atlas 5: 1-274. first reproduction. The descent of Brinton, E. 1967b. Vertical migration and avoidance capa­ P. stephanophrys from the water column to the bility of euphausiids in the California Current. Limnol. benthos and its concomitant trophic shift are Oceanogr. 12: 451-483. probably related to these phenomena. de León González, J.A. 1990. Polychaetos (Anne1ida: Polychaeta) de fondos blandos de la plataforma conti­ ACKNOWLEDGEMENTS nental de la costa oeste de Baja California Sur, México. Resúm. VIII Simp. Internac. Bio!. Mar., Ensenada, Mexico, No. 63. We thank the Instituto Politécnico Nacional of Mexico, who financed the first author's Hureau, J.-C. 1986. Triglidae, pp. 1230-1238. In P.J.P. M.Sc. thesis, from which this paper derived; Whitehead, M.L. Bauchot, J.-C. Hureau,J. Nielsen & E. Tortonese (eds.). Fishes of the Northeastern the Centro de Investigaciones Biológicas del Atlantic aild the Mediterranean I Poissons de Noroeste, where this research was carried out l'Atlantique du Nord et de la Méditerranée. Vol. 1II. as part of a project on benthic resources of the UNESCO, Paris. area; the Consejo Nacional de Ciencia y Tecnología, who supported this project; Sally J. Jardas, J. & Zupanovi'c, S. 1983. Ishrana i neke druge karakteristike populacije lastavice, Trigla Iyra L., 1758, Holbrook, who commented on an earlier draft (Pisces, Triglidae) u podrucju juznojadrans kotline of the manuscript; Sergio Bejarano, who drew (Crnogorsko primorje). Studia Marina, Jugoslavia 13- the figures; and the crew ofR/V "El Puma". 14: 167-1 87.

Kohn, AJ. & A.C. Riggs. 1982. Sample size dependence in measures of proportional sirnilarity. Mar. Eco!. Prog. RESUMEN Ser. 9: 147-151.

Se estudiaron los hábitos alimenticios (composición, Longhurst, A.R. 1967. The pelagic phase of Pleurancodes intensidad, diversidad, cambios ontogéneticos y esta­ planipes Stimpson (Crustacea, Galatheidae) in the cionales) de Prionotus stephanophrys, Bellator gymnos­ California Current. Calif. Coop. Oceanic Fish. Invest., tethus y P. albirostris en la costa del Pacífico de Baja Rept. 11: 142-154. California Sur, México. Se capturaron 547 individuos de las tres especies con red de arrastre entre 1988 y 1990. El Margalef, R. 1980. Ecología. Omega, Barcelona. 951 p. eufáusido Nyctiphanes simplex fue la presa principal de B. gymnostethus, que lo consumió durante las horas diur­ Meléndez C., R. 1987. Nuevos antecedentes de Prionofus nas, y de P. stephanophrys, que lo hizo en la noche y al stephanophrys Lockington, 1880 (Pisces, Triglidae). atardecer; los individuos mayores de P. stephanaphrys Not. Mens. Mus. Nae. Hist. Nat. Chile 314: 1-3. SCHMITTER-SOTO & CASTRO-AGUIRRE: Trophic comparison among Triglidae 811

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