Feeding Habits and Trophic Morphology of Inshore Lizardfish

J. Appl. Ichthyol. 21 (2005), 525–530 Received: August 2, 2004 2005 Blackwell Verlag, Berlin Accepted: December 31, 2004 ISSN 0175–8659

Feeding habits and trophic morphology of inshore lizardfish (Synodus foetens) on the central continental shelf off Veracruz, Gulf of Mexico By V. H. Cruz-Escalona1, M. S. Peterson2, L. Campos-Da´vila3 and M. Zetina-Rejoń1

1Departamento de Pesquerıás y Biologıá Marina, Instituto Politećnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico; 2Department of Coastal Sciences, The University of Southern Mississippi, Ocean Spring, MS, USA; 3Centro de Investigaciones Biolo´gicas del Noroeste S. C., Laboratorio de Ictiologıá, Col. Playa Palo de Santa Rita, La Paz, Baja California Sor, Mexico

Summary The inshore lizardfish, Synodus foetens, is one of the most Synodus foetens is a dominant species in the GOM, where it common coastal demersal predators on the continental shelf is often caught in shrimp trawls and discarded as a trash fish of the Gulf of Mexico (GOM), but the biology and feeding (Robins and Ray, 1986; Garcıá-Abad et al., 1999). Knowledge ecology of this species is virtually unknown. Between about the importance of this species in the GOM food web is November 2001 and January 2003 (10 collections), 603 limited because there are few studies published on the feeding individuals of S. foetens ranging from 112 to 420 mm habits. Those that have been conducted indicate the import- standard length (SL) and 13 to 630 g (wet weight) were ance of fishes and the minor importance of prey such as collected from the continental shelf of Alvarado, Veracruz, crustaceans in their diet (Beebe and Tee-Van, 1928; Randall, Mexico. About 60% of the individuals had empty stomachs 1967; Carr and Adams, 1973; Divita et al., 1983; Prappas, with the stomach fullness of the remaining individuals being 1985; Golani, 1993; Bowman et al., 2000). Phelps (1997) distributed as follows: 5% full (24.8%), 50–75% full (13.5%), documented 18 prey items of S. foetens ranging from 35 to and completely full (1.7%). The mean (± SD) wet weight of 235 mm SL off the central Florida east coast, and that diet stomach contents was 12.1 ± 10.8 g during the rainy season, switched from larval fish and grass shrimp to juvenile and and 19.0 ± 13.0 g during the nortes season. Seventeen prey adult fishes, squid, penaeid shrimp, and Mugil curema with items were identified, with the majority thereof being fish. increased body length. Phelps (1997) also documented a The most important prey items were Upeneus parvus, Loligo significant exponential increase in prey length with increasing pealei, Engyophrys senta, Trachurus lathami, and Anchoa S. foetens size; this switch to larger prey was accompanied by a hepsetus. Seasonal changes in the diet were observed, with significant increase in mouth gape and diameter. Finally, U. parvus and L. pealei being the most important prey during Sweatman (1984) noted that Engleman’s lizardfish (S. engle- the nortes season, whereas E. senta and L. pealei were the mani) were voracious, ambush predators on Australian coral main items during the rainy season. Prey size selection was reefs, and could eat 12% of their body weight per day. evident among size classes of S. foetens, although no trophic However, these studies were qualitative, occurred in nearshore areas only, and/or are based on juveniles or young adults. overlap was observed among size classes (Cik £ 0.004). High trophic level values were determined for all size classes by Food habit and trophic morphology studies of fishes are season (rainy season ¼ 4.67, nortes season ¼ 4.84), and necessary to understand the role they play in the trophic food indicated this species belongs to the piscivorous trophic guild web (Gerking, 1994; Luczkovich et al., 1995). These data are that preys upon both demersal and pelagic species. now being integrated into conceptual models that allow a better understanding of the structure and function of diverse aquatic ecosystems (Pauly and Christensen, 2000). However, Introduction there are no data focusing on the feeding ecology of adults of The inshore lizardfish, Synodus foetens, is a bottom dweller this abundant species, which is believed to consume a number found in the nearshore out to 15 fathoms. Its range is from of commercially, or ecologically important nekton on the Massachusetts to Brazil, including Bermuda, the Gulf of central continental shelf off Veracruz, Mexico. The primary Mexico (GOM), the West Indies to the mouth of the goals of this study were to (i) provide a quantitative Amazon River (Hoese and Moore, 1998; McEachran and description of the diet, (ii) describe ontogenetic changes in Fechhelm, 1998). They are found in a wide variety of diet and mouth morphology of this species, and (iii) measure habitat types ranging from open ocean habitats over the prey size selection. continental shelf, shallow and deep sand flats among seagrass, and inshore in saltwater creeks, rivers, bays, Material and methods sounds, and deep channels within lagoons. They are solitary voracious predators that probably are denser over mud Synodus foetens used in this study were obtained as by-catch bottoms than shell or calcareous bottoms because they from the commercial shrimp fishery (November 2001–January burrow into bottom sediments. In Mexico, S. foetens are 2003; see Table 1 for details) on the continental shelf of considered estuarine-dependent as young use coastal lagoons Alvarado, Veracruz, Mexico (1840¢–1900¢N and 9540¢– as nurseries (Garcıá-Abad et al., 1999). 9557¢W). Mean annual temperature in the area is 27C;

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Table 1 SL SL W W Summary statistics for Synodus foetens Season N (mm; mean ± SD) (mm; range) (g; mean ± SD) (g; range) captures on the continental shelf of Alvarado, Veracruz, Mexico by Rainy collection date September 1, 2002 102 214 ± 42 130–310 119 ± 66 14–302 September 24, 2002 24 193 ± 38 120–260 107 ± 59 13–271 October 1, 2002 24 171 ± 33 120–230 95 ± 53 11–241 Nortes November 29, 2001 21 357 ± 95 165–435 275 ± 208 20–1045 February 7, 2002 87 237 ± 63 110–398 183 ± 138 13–695 February 9, 2002 90 261 ± 69 121–438 202 ± 152 15–766 February 8, 2002 51 195 ± 52 90–327 151 ± 114 11–572 November 11, 2002 39 212 ± 56 98–355 164 ± 124 12–622 November 25, 2002 45 289 ± 77 133–460 222 ± 168 16–844 January 27, 2003 96 223 ± 59 103–374 172 ± 180 13–654

SL, standard length; W, wet weight. during autumn and winter seasons the area is affected by items, whereas high values indicate a generalist diet nortes (Fairbridge, 1967) with high winds from the NW and a (Labropoulou and Eleftheriou, 1997; Labropoulou et al., high pluvial precipitation (Anonymous, 1972). 1999). Additionally, diet overlap between the size classes was The shrimp fleet in Mexico uses standard otter trawls (20 m calculated by using the simplified Morisita’s index (Krebs, long, 10 m wide, and 4.5 cm mesh size). Fishes were only 1989; Hall et al., 1990): collected during the rainy (June–September) and the nortes P 2 p p season (October–February). Fishes were separated from cat- P j ijPkj Cik ¼ 2 2 ches, injected with 10% formalin to interrupt the digestive j pij þ j pkj process, and frozen until examined. where Cik ¼ simplified Morisita’s index for predators i and k; Standard length (SL), and vertical (MV) and horizontal and pij and pkj ¼ proportions of predator i and k with prey j (MH) mouth openings were measured to the nearest 1 mm with in their stomachs. When Cik approaches 0, diets do not contain a vernier caliper. Predator mouth area (MA) and prey cross- items in common, whereas when Cik approaches 1, there is sectional area (PA) were estimated as an ellipse following high similarity between diets. Finally, we calculated the trophic Erzini et al. (1997) following criteria employed by Karpouzi level of inshore lizardfish based on Pauly et al. (1998) and and Stergiou (2003): MA or PA ¼ 0.25 p (MVMH); where MA Pauly and Christensen (2000). The trophic level for any is the mouth area, PA is the prey cross-sectional area, MV is consumer species i is: vertical mouth opening or prey height and MH is the horizontal mouth opening or prey width. Specimens of Xn S. foetens were grouped into seven size classes: class I (120– TROPHi ¼ 1 þ DCijTROPHj 150 mm); class II (151–180 mm); class III (181–210 mm); class j¼1 IV (211–240 mm); class V (241–270 mm); class VI (271– 300 mm); and class VII (>300 mm SL). Stomach fullness was where, TROPHi is the fractional trophic level of prey j and qualitatively assessed as 0 (empty), 1 (25% full), 2 (50–75% DCij represents the fraction of j in the diet of i. Values range full), and 3 (completely full). between 2 for herbivores and detritivorous organisms and 5 for Stomach contents were sorted and identified to the lowest piscivorous and carnivorous organisms. taxonomical level using standard taxonomic keys (Fischer, Linear regression was used to compare mouth opening (Mv and MH) and SL. Additionally, a curvilinear model in the form 1978; Robins and Ray, 1986; Hoese and Moore, 1998). b Percentage number (%N; the percentage of total individual of y ¼ aX was used for all other comparisons, where prey items consumed per prey category), percentage wet X ¼ independent variable, Y ¼ dependent variable, and a weight (%W; the percentage of total prey weight consumed and b are parameters. All P-values are considered significant per prey category), and frequency of occurrence (%FO; the when a < 0.05. percentage of fish stomachs containing food per prey category) were calculated for each fish. Wet weight was Results determined with a Ohaus analytical balance (± 0.001 g). A total of 603 fish were caught (rainy season ¼ 150; nortes Finally, prey-specific abundance (Pi) was calculated as the number of prey i divided by the total number of prey in the season ¼ 453) between 112 and 420 mm SL. About 40% stomach that contained the prey i (Amundsen et al., 1996). (n ¼ 246) had food in their stomachs, which yielded 17 prey species. The distribution of the degree of stomach We plotted Pi against %FO to assess the feeding strategy of the predator (Amundsen et al., 1996). fullness of these individuals was 24.8% (25% full), 13.5% Diet breadth was calculated using Levin’s standardized (50–75% full), and 1.7% (completely full). The mean index (Krebs, 1989): (± SD) wet weight of the stomach contents (g) was "# 12.1 ± 10.8 during the rainy season, and was 19.0 ± 13.0 1 1 during the nortes season. Prey with the most important BA P 1 ¼ 2 values of %N, %W, and %FO in the trophic spectrum of n 1 j p ij S. foetens were Upenaeus parvus, Loligo pealei, Trachurus where, BA ¼ Levin’s standardized index for predator i; lathami, Anchoa hepses, and Engyophrys senta (Table 2). pij ¼ proportion of diet of predator i that is made up of prey During the rainy season, the diet was composed of nine j; and n ¼ number of prey categories. This index ranges from species (Fig. 1a) whereas 13 species were consumed during the 0 to 1 and low values indicate a diet dominated by few prey nortes season (Fig. 1b). The Pi–FO plot demonstrates a mixed Feeding habits and trophic morphology of inshore lizardfish 527

Table 2 Diet composition of 246 inshore lizardﬁsh, Synodus foetens, from the Gulf of Mexico oﬀ Veracruz, Mexico expressed as percentage by number (%N), weight (%W), and frequency of occurrence (%FO)

Prey %N %W %FO

Mollusca Cephalopoda Loliginidae Loligo pealei 15.24 24.11 20.73 Osteichthyes Aulopiformes Synodontidae Saurida brasilensis 3.81 2.89 7.32 Gadiformes Bregmacerotidae Bregmaceros cantori 2.86 1.38 4.88 Clupeiformes Engraulidae Anchoa hepsetus 8.57 5.08 9.76 Clupeidae Harengula clupeola 3.81 5.74 4.88 Perciformes Serranidae Diplectrum bivvitatum 2.86 3.84 4.88 Serranus atrobranchus 1.90 2.73 2.44 Carangidae Trachurus lathami 12.38 8.42 6.10 Lutjanidae Pristipomoides aquilonaris 5.71 3.15 7.32 Gerreidae Eucinostomus gula 1.90 1.33 1.22 Haemulidae Haemulon aurolineatum 0.95 1.28 1.22 Sciaenidae Micropogonias furnieri 2.86 5.56 3.66 Mullidae Upeneus parvus 26.67 17.71 35.37 Trichiuridae Trichiurus lepturus 0.95 1.91 2.44 Pleuronectiformes Bothidae Engyophrys senta 7.62 13.07 12.20 Syacium gunteri 0.95 1.37 2.44 Cynoglossidae Symphurus plagiusa 0.95 0.41 1.22 feeding strategy for S. foetens, with varying degrees of specialization (mainly E. senta and L. pealei) and generaliza- tion on seven different prey items. During the nortes season, however, the preference plot show that U. parvus and L. pealei were clearly the more preferred prey types, followed by T. lathami, Harengula clupeola, Micropogonias furnieri, and Fig. 1. Plot of prey-specific abundance vs frequency of occurrence of A. hepsetus (Fig. 1b), plus seven species more rarely consumed each prey species in the diet of Synodus foetens in the rainy season (a) and the nortes season (b). Codes represent species. Es, Engyophrys (Fig. 1b). There was moderate niche breadth pooled among senta; Lp, Loligo pealei; Sb, Saurida brasilensis; Tl, Trichiurus lepturus; size classes (rainy BA ¼ 0.49, nortes BA ¼ 0.41). Up, Upeneus parvus; Bc, Bregmaceros cantori; Pa, Pristipomoides The MV and MH mouth openings were linearly related to SL aquilonaris; Db, Diplectrum bivittatum; Sg, Syacium gunteri; Ah, 2 Anchoa hespsetus; Hc, Harengula clupeola; Mf, Micropogonias furnieri; [MV ¼ 1.2578(SL) ) 0.9412; r ¼ 0.83; F1,91 ¼ 447.30; ) 2 Eg, Eucinstomus gula; Ha, Haemulon aurolineatum; Sa, Serranus P < 0.0001; and MH ¼ 1.1554(SL) 5.8559; r ¼ 0.90; atrobranchus; Sb, Smphurus plagiusa; Tla, Trachurus lathami F1,91 ¼ 783.79; P < 0.0001] whereas the mouth area (MA) 2.2801 was a curvilinear function of SL (MA ¼ 0.335(SL) ; Bregmaceros cantori occurring most frequently (Fig. 2). The diet 2 r ¼ 0.94; F1,244 ¼ 1710.4; P < 0.001). There was also a clear of S. foetens in the 150–180 mm size class was more focused on and strong relationship between MA in S. foetens and consumed Symphurus plagiusia, and E. senta. Fishes in the 181–210 mm 0.958 2 prey area [prey area ¼ 1.2966 (MA) , r ¼ 0.9423; size class preyed mainly upon L. pealei, T. lathami, and Saurida F1,88 ¼ 917.77; P < 0.0001]. We also found a strong relation- brasilensis, whereas the largest S. foetens (>210 mm) fed mainly ship between MA and mean predator SL, which suggests prey on U. parvus, T. lathami, Diplectrum bivittatum, Pristipomoides size selection [prey area (mm2) ¼ 100.18 (SL)1.0697; aquilonaris, and M. furnieri (Table 3 and Fig. 2). 2 r ¼ 0.9702; F1,244 ¼ 10217; P < 0.0001]. This prey size There was no measurable diet overlap noted for most size selection was evident between successive size classes of S. foetens. class comparisons in either season, except a minor diet overlap The smallest size class of S. foetens (£15 cm SL, class I) between size classes III–IV in the rainy (Cik ¼ 0.003) and the consumed a narrow variety of bony fishes, with A. hepsetus and nortes (Cik ¼ 0.004) season. These data suggest that some diet 528 V. H. Cruz-Escalona et al.

1200 Prey area = 100.18 (SL)1.0697 r2= 0.9702 1000 n = 246 )

2 800 Micropogonias furnieri Pristipomoides aquilonaris Pristipomoides n = 39 Eucinostomus gula Eucinostomus Haemulon aurolineatum Haemulon 600 n = 46 Upeneus parvus Loligo pealei Loligo Loligo pealei Loligo Trichiurus lepturus Brasiliensis Saurida Saurida brasiliensis Saurida

Prey area (mmPrey 400 n = 59 Engyophrys sentaEngyophrys Symphurus plagiusa Symphurus Anchoa hepsetus Bregmacerus cantori n = 28 Fig. 2. Plot of prey area 200 (mean ± minimum and maximum, n = 34 mm2) and prey items by size class n = 32 [mean of size class standard length n = 8 0 (SL)] of the inshore lizardﬁsh, Synodus II II II IV V VI VII foetens, over the central continental shelf of Gulf of Mexico oﬀ Veracruz, Predator sIze class Mexico

Table 3 Wet weight (%) of food items in the diet of seven size classes of Synodus foetens collected on the continental shelf oﬀ of the Alvarado lagoonal complex, Veracruz, Mexico

Prey/size class interval I II III IV V VI VII (mm SL) (120–150) (151–180) (181–210) (211–240) (241–270) (271–300) (>300)

Rainy season (n ¼ 6) (n ¼ 24) (n ¼ 26) (n ¼ 21) (n ¼ 37) (n ¼ 33) Bregmaceros cantori 100 Diplectrum bivittatum 80 Engyophrys senta 90 Loligo pealei 90 17 6 Pristipomoides aquilonaris 100 Saurida brasilensis 9 Syacium gunteri 10 Trichiurus lepturus 1 Upeneus parvus 87 14 Nortes season (n ¼ 2) (n ¼ 8) (n ¼ 8) (n ¼ 7) (n ¼ 22) (n ¼ 13) (n ¼ 39) Anchoa hespsetus 100 Diplectrum bivvitatum 50 Eucinostomus gula 525 Haemulon aurolineatum 25 Harengula clupeola 29 5.8 Loligo pealei 90 2 Micropogonias furnieri 80 Pristipomoides aquilonaris 14 2.8 Saurida brasilensis 7 Serranus atrobranchus 14 2.8 Smphurus plagiusa 100 Trachurus lathami 43 8.6 Upeneus parvus 393 specialization occurs between size classes in S. foetens. There example, taxonomic identification is difficult because of the was no apparent inter-season difference in trophic level in digestive process (Iken et al., 1999) and some components in the S. foetens, but there was a general increase in trophic level (prey diets are difficult to quantify, such as gelatinous plankton and consumed) with increasing size, which was 4.67 in the rainy detritus (Deb, 1977; Polluning and Pinnegar, 2002). Finally, season and 4.84 in the nortes season. The largest size class was because stomach contents are based on prey consumed shortly characterized by the highest trophic level. before capture, they represent a limited view of the diet in time and space (Pinnegar et al., 2002; Cocheret de la Moriniere et al., 2003), and often high percentages of stomachs are empty (Divita Discussion et al., 1983; Brewer et al., 1991). Under the assumption that Stomach content analysis is used widely to determine food response to human disturbance in marine ecosystems is con- composition, feeding strategies, trophic position, energy flow spicuous in higher taxa (Rogers et al., 1999), we believe that (Hyslop, 1980), trophic structure (Luczkovich et al., 2002), and stomach contents of top carnivores are an excellent way to trophic partitioning (Ross, 1986) of predator and prey. evaluate the relationship between predators and food source. Although this technique is the most commonly employed Relatively little is known about the natural history of method to evaluate these relationships (Hannon and Joiris, S. foetens, although it ranges extensively over the GOM (Hoese 1989), the method presents some inherent difficulties. For and Moore, 1998; Garcıá-Abad et al., 1999). We found that Feeding habits and trophic morphology of inshore lizardfish 529

S. foetens fed mainly on fishes (17 species) in all size classes, with S. foetens occur in many coastal lagoons of Mexico (e.g. only L. pealei appearing frequently in size class III. The frequent Terminos Lagoon, Garcıá-Abad et al., 1999; and the Alvarado presence of fishes such as U. parvus, A. hepsetus, Eucinostomus lagoonal system, Cha´vez-Lo´pez et al., 2005) and may consume gula, E. senta, T. lathami, and, in lesser proportion, other prey penaeid shrimp during that period of their life history. In other like L. pealei in the stomach contents suggest that this species GOM studies, fishes collected in nearshore environments feeds on both demersal and pelagic prey, many of which are consume penaeid shrimps in various amounts (Diener et al., themselves predators. Additionally, the variety of prey reflects a 1974; Sheridan and Trimm, 1983), which is based mainly on large home range (Hoese and Moore, 1998) that includes several predator size and sample depth (different prey spectra available; habitat types (Garcıá-Abad et al., 1999) ranging from sand Divita et al., 1983). In Texas coastal waters, penaeid shrimp bottoms (S. plagiusa, E. senta), and mid-water (H. clupeola, were more important in small predators and in only 31 of 81 L. pealei, T. lathami), to those associated with benthic substrata species (Divita et al., 1983) which did not include S. foetens.In (E. gula), or those that are clearly demersal (S. brasiliensis). Prey contrast, fishes appear to be the most important predators of from sand bottom and mid-water habitat types were more shrimp in 37 of 52 piscivorous species of fish in the Embley common in the diet than prey from the two other habitat types. Estuary, Australia (Salini et al., 1990; Brewer et al., 1991). This feeding behavior is in contrast to anecdotal reports that The high trophic level values determined for all size classes lizardfish remain motionless for long periods, often buried in the examined are directly related to the prey item consumed. Most sand, and ambush prey (Hiatt and Strasburg, 1960; Starck and of the prey found in the stomachs themselves occupies higher Davis, 1966; Hobson, 1974). However, Sweatman (1984) found trophic levels (except for the zooplanktivore B. cantori). These that S. englemani were active hunters, individuals move high trophic level values documented for offshore individuals frequently over distances of up to 1.5 m between elevated rock may differ for juveniles that occupy inshore estuaries and from which they scan the surroundings for prey. Regardless of lagoons (see Phelps, 1997 for diets of smaller individuals) as which habitat type they forage within, the important prey listed our data are based on adults collected offshore. Despite this above are also abundant species in the GOM, and are considered fact, the trophic level estimation is a good way to demonstrate key species in the dynamics of this marine community (Yan˜ ez- how S. foetens affect high trophic levels through predation on Arancibia et al., 1985; Robins and Ray, 1986; Yań˜ ez-Arancibia the juveniles of other predators. Apparently S. foetens is and Sańchez-Gil, 1988; Campos-Da´vila et al., 2002). extremely opportunistic. In this sense, we conclude that Other researchers have also found the diet of Synodus to be S. foetens is a demersal marine apex piscivore consuming a dominated by fishes (Sweatman, 1984; Golani, 1993; Phelps, diverse diet, and that this foraging pattern is based on both 1997; Bowman et al., 2000). However, the importance of prey and predator morphometry. specific types of fishes and others prey in Synodus diets vary with prey availability and abundance, as well as the size of the lizardish species that consumes them. For example, Sweatman Acknowledgements (1984) found that the small lizardfish, S. englemani, in coral The research that led to this paper was funded by the Consejo reef environments consume a wide spectrum of small fish prey Nacional de Ciencia y Tecnologıá (CONACyT-34865-B and (Apogon gracilis, Parupeneus trifasciatus, Pomacentrus popei, 2003-02-157), and by the Instituto Politećnico Nacional Halichoeres hoeveni, and Amblygobius phaelena) across an (CGPI-20010827, EDI, and COFAA). VHCHE and MZR array of habitat types. are supported by fellowships of the Sistema Nacional de We also observed an ontogenetic shift in prey species and Investigadores (SNI). prey area consumed as S. foetens increased in size. As we examined progressively larger organisms, fish became more common among prey found in the diet; the mean prey body References area also increased from below 200 to over 800 mm2. The Amundsen, P. A.; Gabler, H. M.; Staldvik, F. J., 1996: A new method strong relationship between SL and various mouth size for graphical analysis of feeding strategy from stomach contents data-modification of the Costello (1990) method. J. Fish Biol. 48, measures support their role as an apex predator on the 607–614. continental shelf environment. Diets of larger S. foetens were Anonymous, 1972: Planeacioń e instalacioń de la red de muestreo de characterized by an increased %W of fish prey and larger food calidad del agua en las zonas de alta contaminacioń. Secretaria de items. For example, smaller S. foetens showed a high level of Recursos Hidraúlicos, Rıó Blanco, Veracruz, Me´xico. preference for small prey such as A. hepsetus, and flatfishes Barreiros, J. P.; Santos, R. S.; Borba, A. E., 2002: Food habits, schooling and predatory behaviour of the yellowmouth barra- (S. plagiusa, E. senta), whereas the large S. foetens fed mainly cuda, Sphyraena viridensis (Perciformes: Sphyraenidae) in the on big prey such as U. parvus, T. lathami, and M. furnieri. These Azores. Cybium 26, 83–88. relationships underscore that the morphologic design of a Beebe, W.; Tee-Van, J., 1928: The fishes of Port-au-Prince, Haiti, with predator has a strong influence on its feeding ecology. For a summary of the known species of marine fish of the island of Haiti and Santo Domingo. Zoologica 10, 1–279. example, Phelps (1997) showed that young S. foetens (35– Bocanegra-Castillo, N.; Abitia-Cardenas, L. A.; Cruz-Escalona, V. H.; 235 mm SL) switched from larval fish and grass shrimp to Galvań-Magan˜ a, F.; Campos-Davila, L., 2002: Food habits of the juvenile and adult fishes, squid, penaeid shrimp, and M. curema spotted sand bass Paralabrax maculatofaciatus (Steindachner, with increased body length. In contrast, Sweatman (1984) did 1868) from Laguna Ojo de Liebre, B.C.S., Mexico. Bull. Soc. Calif. not find a relationship between mouth length and prey length in Acad. Sci. 101, 13–23. Bowman, R. E.; Stillwell, C. E.; Michaels, W. L.; Grosslein, M. D., Engleman’s lizardfish ranging from 56 to 113 mm SL, suggest- 2000: Food of northwest Atlantic fishes and two common species of ing consumption of a wide spectrum of prey size when small. squid. NOAA Technical Memorandum, NMFS-NE #155, 138 pp. Although this latter pattern may be true, it is equally likely that Brewer, D. T.; Blaber, S. J. M.; Salini, J. 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