fish assemblages around espiritu santo island and ...

BULLETIN OF MARINE SCIENCE, 77(1): 33–50, 2005

FISH ASSEMBLAGES AROUND ESPIRITU SANTO ISLAND AND ESPIRITU SANTO SEAMOUNT IN THE LOWER GULF OF CALIFORNIA, MEXICO Jesús Rodríguez-Romero, Arturo Fabian Muhlia-Melo, Felipe Galván-Magaña, Francisco Javier Gutiérrez-Sánchez, and Vicente Gracia-Lopez ABSTRACT

Fish composition, abundance, and diversity were recorded by visual censuses at five sites near the Espiritu Santo Island and one near the Espiritu Santo Seamount, and compared to hydrographic parameters (salinity, oxygen, water temperature). Surveys conducted between November 1995 and October 1996 recorded 51,099 fishes, belonging to 41 families, 82 genera, and 120 species. The most common species near the island were: sergeant major, Abudefduf troschelii; Cortez rainbow wrasse, Thalassoma lucasanum; scissortail damselfish, Chromis atrilobata; Cortez damselfish, Stegastes rectifraenum; bluebarred parrotfish, Scarus ghobban; Pacific creolefish, Paranthias colonus; yellow snapper, Lutjanus argentiventris; Cortez sea chub, Kyphosus elegans; king angelfish, Holacanthus passer; and Mexican goatfish, Mulloidichthys dentatus; whereas in the seamount were: Pacific creolefish; Cortez damselfish; Cortez rainbow wrasse; black skipjack, Euthynnus lineatus; king angelfish; red snapper, Lutjanus peru; yellow snapper, mackerel scad, Decapterus macarellus; mullet snapper, Lutjanus aratus; and Mexican goatfish. Fish abundance and diversity changed seasonally between the island and the seamount, mainly related to the topographical differences between the two sites. The island has protected and shallow areas, substrate with small rocks to moderate sandy patches; whereas the seamount is in deep water, has strong currents, large boulders on the benthos, and no protective areas.

Seamounts and islands in tropical environments typically have a high faunal diversity and complexity because several habitats, including rocky zones and coral reefs, exist (Letourneur, 1996). While the fish fauna in the lower Gulf of California is considered to be one of the most diverse (Thomson et al., 2000), as a result of unique oceanographic characteristics (Walker, 1960; Alvarez-Borrego and Schwartzlose, 1979), relatively little is known about the fauna of islands and seamounts in the area. The rocky reef fishes are part of a complex ecosystem and Espiritu Santo Island and Espiritu Santo Seamount are important areas of artisanal and sport fishing and other underwater recreational activities. From 1993 to 1998, an intensive extraction of ornamental fish from the lower Gulf of California occurred (Almenara-Roldan, 2000), with unknown effects on the distribution and abundance of fish in these marine ecosystems. The selective extraction of fishes from a highly diverse fish community could seriously affect the structure and functioning of the communities. Community response cannot be predicted, however, without monitoring populations. Such records of abundance of fish species are necessary and particularly important in this ecological area to regulate ecosystem degradation (Roberts and Ormond, 1987). Several studies have been done around Espiritu Santo Island (Sánchez et al., 1997; Arreola, 1998; Aburto, 1999); however, there are no fish studies around the seamount. Bulletin of Marine Science

© 2005 Rosenstiel School of Marine and Atmospheric Science of the University of Miami

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BULLETIN OF MARINE SCIENCE, VOL. 77, NO. 1, 2005

To provide a baseline record for measuring spatial and seasonal variations in their distribution, relative abundance, and diversity of the fish assemblages, we analyzed the structure of fish communities that inhabit the Espiritu Santo Island and the Espiritu Santo Seamount. METHODS STUDY AREA.—Espiritu Santo Island (island) and Espiritu Santo Seamount (seamount) are located in the lower Gulf of California (24°36–24°24N, 110°15–110°25W; Fig. 1). Rocks of varying dimensions and reef patches with sandy areas characterize the submarine substrate of the island. The seamount is in deeper water with its peak at 18 m below the surface. The seamount substrate has boulders covered with coral patches. Deep water of about 500 m surrounds the seamount (about 35 km from the coast and 12 km from the island). Each site has different topographic characteristics: Site 1 (El Embudo) consists of rocks and small reef patches; Site 2 (El Cardonal) and Site 3 (La Gallina) have rocks, coral patches, and small sandy areas; Site 4 (San Gabriel) has medium rocks, areas of fine sand, and coral patches; Site 5 (El Faro) has medium rocks with coral reef and sandy patches; and Site 6 (Espiritu Santo Seamount) consists of large boulders and coral reefs. SAMPLING.—A visual census was undertaken monthly from November 1995 through October 1996, using free and SCUBA diving. We sampled six sites, diving in transects 100 m long and 6 m wide for 25 min each (surveys modified from Hermelin-Vivien et al., 1985; Bohnsack and Bannerot, 1986; and Fowler, 1987). At each site, we recorded water temperature, salinity, dissolved oxygen, time of day, substrate type and form, and associated fauna. Based on the visual survey, we estimated fish assemblages and dominance with the following ecological indices: relative abundance (RA) as:

RA = ( n N ) × 100, where n is the abundance of each fish species, and N is the abundance of all fish; Sander’s Biological Value Index (Loya and Escofet, 1990) is:

BVI = ∑ point ij, where i corresponds to the species and j to the sampling site; Diversity Index (Shannon-Wiener, 1963) is: s

H ′ = − ∑ ( pi ) × log 2 ( pi ), i =1

where H is the diversity, pi is the proportion of species i; and s is the number of species; and evenness as:

E = H ′ H max, where H max is equal to Ln(s) and s is the number of species. A principal components analysis compared seasonal and spatial occurrence of fish species to water temperature, salinity, dissolved oxygen, substrate type, time of day, and depth. We included only the 18 most abundant species in the analysis, according to Sander’s Dominance Index. The data were standardized following the formula Xi = X/SD, where Xi is the absolute

RODRÍGUEZ-ROMERO ET AL.: FISH ASSEMBLAGES IN THE GULF OF CALIFORNIA

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Figure 1. Survey sites in the lower Gulf of California during 1995–1996. value of each parameter (water temperature, salinity, etc.), X is the mean value of each measure, and SD is standard deviation.

RESULTS The survey around the seamount was at 24–27 m depth, whereas near the island, surveys were only at 2–7 m depth. The surface temperature was lowest in winter (21 °C), and highest in summer (30 °C). Salinity was stable at 34.9 in winter, and 35.5 in fall and spring. Dissolved oxygen changed from 5.7 mg L−1 in fall to 7.9 mg L−1 in spring (Table 1). In total, 72 transects were surveyed at six sites, where 51,099 fishes were counted. We identified 120 species in 82 genera and 41 families (Appendix 1). The largest number of species was recorded in fall; however, the greatest abundance occurred in summer. The greatest number of species was observed at the seamount, followed by site 1 near the island (Table 2). When species were examined by site and season (Fig.

24.8

35.0

5.9

24.0

35.0

5.7

4.0

Salinity

Oxygen (mg L−1)

Depth (m)

23.5

35.0

6.8

24.0

35.0

6.5

4.0

Salinity

Oxygen (mg L−1)

Depth (m)

4.0

2

1

Sites Parameters Temperature (°C)

4.0

2

1

Sites Parameters Temperature (°C)

Fall

Spring

5.0

6.8

35.0

23.6

3

5.0

6.3

36.0

24.0

3

4.0

7.4

35.0

23.9

4

4.0

6.4

35.0

25.0

4

5.0

8.0

36.0

25.0

5

5.0

6.1

35.0

25.0

5

25.5

6.5

35.1

24.8

6

25.5

6.0

35.1

24.0

6

4.0

6.2

35.0

28.4

1

4.0

7.2

35.0

21.0

1

4.0

6.1

35.0

29.0

2

4.0

7.2

35.0

21.0

2

4.0

7.2

35.1

21.5

4

5.0

6.0

35.0

29.0

4.0

6.0

35.0

29.2

Summer 3 4

5.0

7.3

35.0

21.5

Winter 3

5.0

6.0

35.0

30.0

5

5.0

7.3

35.0

21.5

5

25.5

5.8

35.0

29.9

6

25.5

6.8

34.9

21.0

6

Table 1. Seasonal changes in mean environmental parameters measured at six sites in the study area: 1 = El Embudo, 2 = El Cardonal, 3 = La Gallina, 4 = San Gabriel, 5 = El Faro, 6 = Espiritu Santo Seamount. See Figure 1 for site locations.

36 BULLETIN OF MARINE SCIENCE, VOL. 77, NO. 1, 2005

Site 1 2 3 4 5 6 Total

E 0.72 0.77 0.7 0.78 0.79 0.7 0.74

H´ 4.2 4.4 3.8 4.6 4.4 4 4.8

Fall

Sp 59 50 43 58 49 52 93

n 1,647 2,003 1,946 2,248 1,836 2,565 12,245

E 0.7 0.8 0.8 0.8 0.9 0.8 0.8

Winter H´ Sp 4.1 44 4.2 45 4.5 44 4.2 44 4.4 37 4.4 51 4.8 74 n 2,842 2,219 1,103 1,631 1,514 3,101 12,410

E 0.74 0.76 0.69 0.76 0.54 0.7 0.72

Spring H´ Sp n 3.99 43 2,040 4.12 44 1,593 3.69 41 1,246 4.06 40 1,622 2.82 37 1,179 4.1 59 2,778 4.67 91 10,458 E 0.72 0.71 0.72 0.71 0.74 0.59 0.68

Summer H´ Sp n 4.04 48 2,779 3.89 45 2,831 4.03 43 2,065 3.19 43 2,556 3.83 40 1,777 3.9 52 3,978 4.71 86 15,986

E 0.69 0.7 0.7 0.73 0.76 0.68 0.78

Total H´ Sp n 4.3 74 9,308 4.4 73 8,646 4.2 65 6,360 4.5 69 8,057 4.5 60 6,306 4.34 83 12,422 4.9 120 51,099

Table 2. Ecological indices calculated for six sites within the study area.1 = El Embudo, 2 = El Cardonal, 3 = La Gallina, 4 = San Gabriel, 5 = El Faro, 6 = Espiritu Santo Seamount. E = evenness, H´ = Shannon diversity, Sp = number of species, and n = total number of organisms surveyed.


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Figure 2. Seasonal and relative abundance of the 22 most abundant fish species in five sites near Espiritu Santo Island and one site above Espiritu Santo Seamount.

2), 22 species were common to both areas. The permanent species at six sites were: scissortail damselfish (Chromis atrilobata), Cortez rainbow wrasse (Thalassoma lucasanum), and Cortez damselfish (Stegastes rectifraenum). These species were also the most abundant. The sergeant major (Abudefduf troschelii) and Cortez damselfish were the most important species near the island. The sergeant major was not recorded near the seamount, whereas Pacific creolefish (Paranthias colonus), scissortail damselfish, and king angelfish (Holacanthus passer) were permanent and abundant at the seamount. Also, the peppered sawtail (Prionurus punctatus) tended to occur in relatively high abundance at sites 1 and 2, with the highest abundance during summer. Giant damselfish (Microspathodon dorsalis) was numerous during fall only at Site 1. The king angelfish was common at four sites and the blue barred parrotfish (Scarus ghobban) was moderately abundant all year at sites 1, 2, 3, and 5. Bigeye trevally (Caranx sexfasciatus) was important at site 1 during spring and the seamount during summer. Mexican goatfish (Mulloidichthys dentatus) prevailed all year at sites 1, 3, and 5; large numbers of yellow snapper (Lutjanus argentiventris) occurred at sites 2 and 3; and Pacific dog snapper (Lutjanus novemfasciatus) was common


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at site 4 during summer and fall. Other species, such as black skipjack (Euthynnus lineatus), Pacific red snapper (Lutjanus peru), mullet snapper (Lutjanus aratus), and mackerel scad (Decapterus macarellus) occurred only at the seamount. The diversity index was lowest (2.82) at site 5 during spring, and was highest (4.56) at site 4 during fall. At sites 4 and 5, we observed the highest diversity values. For the evenness index values ranged between 0.54 (during spring) and 0.85 (during winter), both values at site 5 (Table 2). For Sander’s Biological Value Index, we found that the most dominant species yearround near the island were: sergeant major, scissortail damselfish, rainbow wrasse, Mexican goatfish, Pacific creolefish, yellow snapper, and Cortez damselfish (Table 3); while at the seamount, the dominant species, varying by season, were: Pacific creolefish (Paranthias colonus), scissortail damselfish, Cortez rainbow, black skipjack, king angelfish, red snapper, yellow snapper, Cortez damselfish, mackerel scad, mullet snapper, and Mexican goatfish (Table 4). The relationship between species abundance and environmental measurements by site are illustrated in Figure 3. At site 1, the dominant species were: peppered sawtail, Cortez rainbow, scissortail damselfish, and giant damselfish, which maintained high correlations with this site north of the island. At site 2, blue-bronze chub (Kyphosus analogus), Mexican goatfish, yellow snapper, and graybar grunt (Haemulon sexfasciatum), had a high correlation with the northwestern side of the island. At site 3, bluebarred parrotfish and Cortez damselfish showed a high affinity with the western side of the island, where the concentration of dissolved oxygen was the highest. At site 4, sergeant major, Mexican barred snapper (Hoplopagrus guntheri), and Pacific dog snapper, maintained high abundance, associated with higher salinity values. At site 5, some species were correlated with water temperature and time of day (1700–1730 hrs), when the dominant species was Mexican goatfish. At the seamount, the most important species were: Mexican hogfish (Bodianus diplotaenia), Pacific creolefish, king angelfish, leopard grouper (Mycteroperca rosacea), and bigeye trevally, which were correlated with substrate type, depth, and overall species abundance. Comparing relationships between species abundance and environmental measurements by season (Fig. 4), we found that Giant damselfish, Mexican goatfish, yellow snapper, and scissortail damselfish were associated with the fall season, when salinity was high. During winter when dissolved oxygen was highest, leopard grouper was the most abundant species, followed by king angelfish, bluebarred parrotfish, Mexican hogfish, graybar grunt, and Cortez damselfish. During spring, the rainbow wrasse and peppered sawtail were dominant, whereas during summer, associated with higher water temperatures, bigeye trevally, blue-bronze chub, Mexican barred snapper, Pacific creolefish, and Pacific dog snapper prevailed. DISCUSSION The fish assemblages on the rocky substrate near the Espiritu Santo Island and the Espiritu Santo Seamount comprise 67 permanent species and 53 seasonal species, which represent 36% of 333 reef fish species in the Gulf of California (reported by Thomson et al., 2000). According to Briggs (1974) and Walker (1960), fish species found in the lower Gulf of California are in a transitional zone, influenced by water masses from the Panamanian Province, where tropical and temperate fishes are dominant. The fish assem-

Fall Abudefduf troschelii Chromis atrilobata Thalassoma lucasanum Mullodichthys dentatus Paranthias colonus Lutjanus argentiventris Scarus rectifraenum Scarus ghobban Lutjanus novemfasciatus Haemulon sexfasciatum Holocanthus passer Elops affinis Mugil hospes Caranx sexfasciatus Microspathodon dorsalis Mugil cephalus Stegastes flavilatus Mycteroperca rosacea Myripristhis leiognathos Kyphosus analogus Sargocentron suborbitalis Euthynnus lineatus Bodianus diplotaenia Prionurus punctatus

BVI 42 41 33 28 26 22 22 16 12 10 9 8 7 7 6 6 5 4 4 3 2 2 1 1

Winter Abudefduf troschelii Thalassoma lucasanum Chromis atrilobata Stegastes rectifraenum Scarus ghobban Holacanthus passer Lutjanus argentiventris Paranthias colonus Mullodichthys dentatus Lutjanus novemfasciatus Prionurus punctatus Kyphosus elegans Sargocentron suborbitalis Myripristhis leiognathos Bodianus diplotaenia Mycteroperca rosacea Mugil cephalus Caranx sexfasciatus Microspahtodon dorsalis

BVI 42 41 28 28 22 19 15 12 11 9 9 8 8 5 4 2 2 1 1

Spring Thalassoma lucasanum Abudefduf troschelii Stegastes rectifraenum Chromis atrilobata Mullodichthys dentatus Scarus ghobban Lutjanus argentiventris Holacanthus passer Bodianus diplotaenia Mugil cephalus Caranx sexfasciatus Microspathodon dorsalis Sargocentron suborbitalis Prionurus punctatus Myripristhis leiognathos Lutjanus novemfasciatus Diodon holocanthus Scarus perrico Cantigaster punctatissima Cirrhitichthys oxycephalus Paranthias colonus Ophioblenius steindachneri Fistularia commersonii Sufflamen verres

BVI 47 44 32 24 23 19 15 10 9 8 7 7 7 6 5 4 4 3 3 3 2 1 1 1

Summer Abudefduf troschelii Chromis atrilobata Thalassoma lucasanum Paranthias colonus Stegastes rectifraenum Lutjanus argentiventris Scarus ghobban Hyporhamphus unifasciatus Kyphosus analogus Mullodichthys dentatus Prionurus punctatus Lutjanus novemfasciatus Hoplopagrus guntheri Elops affinis Microspathodon dorsalis Sargocentron suborbitalis Haemulon sexfasciatum Mugil hospes Balistes polylepis Holacanthus passer Myripristis leiognathus Scarus perrico Caranx sexfasciatus Mugil curema

Table 3. Biological Value Index (BVI) of fish assemblage in the Espiritu Santo Island by seasonal ecological dominance, according to Sanders (1960). BVI 48 39 34 18 17 15 12 11 10 10 9 9 8 8 6 5 4 4 4 3 3 1 1 1

40 BULLETIN OF MARINE SCIENCE, VOL. 77, NO. 1, 2005

Fall Paranthias colonus Chromis atrilobata Thalassoma lucasanum Euhynnus lineatus Decapterus macarellus Mullodichthys dentatus Lutjanus argentiventris Stegastes rectifraenum Prionurus punctatus Holacanthus passer Cypselurus oxycephalus Thalassoma grammaticum Caranx caballus Bodianus diplotaenia Thunnus albacares Canthigaster punctatissima Sufflamen verres Trachurus symmetricus Mycteroperca rosacea Lutjanus aratus Kyphosus elegans Gymnothorax castaneus Ophioblenius steindachneri Lutjanus peru Johnrandallia nigrirostris Balistes polylepis

BVI 20 19 18 17 16 15 14 14 13 12 11 10 9 9 7 7 8 6 5 4 4 3 2 1 1 1

Winter Paranthias colonus Chromis atrilobata Thalassoma lucasanum Lutjanus peru Holacanthus passer Mullodichthys dentatus Harengula thrissina Mycteroperca rosacea Euthynnus lineatus Prionurus punctatus Johnrandallia nigrirostris Decapterus macarellus Stegastes rectifraenum Bodianus diplotaenia Ophioblenius steindachneri Pomacanthus zonipectus Haemulon sexfasciatus Sufflamen verres Balistes polylepis Chaetodon humeralis Cirrhitus rivulatus Cirrhitichthys oxycephalus Diodon holocanthus Thalassoma grammaticum

BVI 20 19 18 17 16 15 15 14 13 12 11 10 9 8 7 6 5 4 3 2 2 1 1 1

Spring Paranthias colonus Thalassoma ucasanum Lutjanus aratus Chromis atrilobata Euhynnus lineatus Lutjanus peru Lutjanus argentiventris Holacanthus passer Prionurus punctatus Bodianus diplotaenia Decapterus macarellus Mullodichthys dentatus Mycteroperca rosacea Balistes polylepis Stegastes rectifraenum Thalassoma grammaticum Sufflamen verres Cirrhitichthys oxycephalus Johnrandallia nigrirostris Canthigaster punctatissima Thunnus albacares Scarus ghobban Epinephelus panamensis Stegastes leucorus Lutjanus viridis

BVI 20 19 18 17 16 15 14 13 12 11 10 9 7 7 6 6 5 4 4 3 2 1 1 1 1

Summer Paranthias colonus Caranx sexfasciatus Chromis atrilobata Thalassoma lucasanum Holacanthus passer Euthynnus lineatus Lutjanus argentiventris Cirrhitichthys oxycephalus Caranx caballus Lutjanus peru Sufflamen verres Chaetodon humeralis Canthigaster punctatissima Balistes polylepis Thunnus albacares Prionurus punctatus Pomacanthus zonipectus Johnrandallia nigrirostris Decapterus macarellus Bodianus diplotaenia Ophioblenius steindachneri Stegastes rectifraenum Thalassoma grammaticum Lutjanus aratus Scarus ghobban Hoplopagrus guntheri

Table 4. Biological Value Index (BVI) of the species in the Espiritu Santo Seamount by seasonal ecological dominance, according to Sanders (1960). BVI 20 20 19 18 17 16 14 13 12 11 10 9 8 7 7 6 6 5 4 4 4 3 3 2 1 1


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Figure 3. Principal component analysis of the most important fish species at Espirtitu Santo Island and Seamount by site and environmental parameters (water temperature, salinity, oxygen, substrate type, total abundance, time, and depth).

blages we surveyed included high numbers of tropical species with distributions from the central Gulf of California to Panama and Ecuador (Allen and Robertson, 1994; Thomson et al., 2000). These transitional areas are found in tropical and subtropical marine ecosystems all over the world (Horn and Allen, 1985; Letourneur, 1996). Relative to other similar studies in the lower Gulf of California (Pérez et al., 1996; Sánchez et al., 1997; Arreola, 1998; Aburto, 1999; and Jiménez, 1999), we recorded more species (120 vs 76–101) suggesting that favorable conditions exist near the island and seamount. Blaber (1985) found more species associated with topographically complex substrates off southwest Africa, and Galván et al. (1996) suggested that fish in rocky substrates near islands have more habitats compared to fish near most continental coastal areas. Studies on reefs of the Indo-Pacific indicated that type and complexity of substrate, topography, refuge availability, and food resources are important in increasing specific diversity (Roberts and Ormond, 1987; Letourneur, 1996). In this survey, habitats with highly diverse substrates were found near the island and seamount, and the most abundant species associated seasonally and spatially with specific habitat types and water temperatures. Overall abundances during summer were similar to results from Perez et al. (1996) and Aburto (1999) in adjacent areas. Jiménez (1999) found the highest abundance of all fishes occurred during the winter season off Cerralvo Island in the Gulf of California, probably associated with juvenile recruitment of dominant species. We observed large numbers of juveniles and adults during summer, associated with abundant food


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Figure 4. Principal component analysis of the most important fish species at Espirtitu Santo Island and Seamount by season, total abundance, and environmental parameters.

supplies. Such seasonal changes in food availability can play an important role in the composition of fish assemblages (Galzin, 1987; Letorneur, 1996). Permanent and abundant species (e.g., seargeant major, Cortez rainbow wrasse, and scissortail damselfish at the island; Pacific creolefish, Cortez damselfish, and Cortez rainbow wrasse at the seamount) were generally able to tolerate relatively wide variations in water temperature. These species are active during the day, and include consumers at the first, second, and third trophic levels, grouping in moderate to large schools close to rocky and reef substrates, where their feeding, courting, socializing, and evasive behaviors were observed. The island and seamount sustain a high diversity of commercially and ecologically important fish. This high biological productivity depends on oceanographic processes, such as upwelling, fronts, and eddies that enhance productivity in the lower Gulf of California. Recent oceanographic studies by Amador et al. (2003) in the lower Gulf of California found a 120-km diameter cyclonic gyre to the north of the island with currents of 45 cm s−1 extending to depths of 500 m. These authors also suggested that a residual anti-cyclonic current close to the seamount and the island is the underlying cause of high productivity in this area. Islands and seamounts influence the movements of water masses, typically causing upwelling that contributes to high food concentration and plankton biomass (Merlin and Ortega, 1997). Islands and seamounts also have strong impacts on juvenile and adult pelagic and reef fish aggregations. Some studies of pelagic fishes (Klimley and Nelson, 1984) and fish larvae (R. Gonzalez-Armas, CICIMAR, pers. comm.) in our study area have

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found large quantities of eggs, larvae, and juveniles of some pelagic fish, mainly close to the seamount. The composition of fish assemblages near the island and seamount were somewhat different, perhaps reflecting the protected and shallow island habitats dominated by small rocks and sandy patches, and the deeper habitats of the seamount dominated by large boulders and few protected areas with strong currents. In addition, shallower depths and higher water temperature favor higher flora and faunal levels, increasing the availability of food and refuge areas. Of the 83 species recorded over the seamount, 14 were not present near the island and of the 106 species recorded near the island, 34 species were not present at the seamount. There were also differences in dominance. For example, Pacific sergeant major is a permanent and dominant resident near the island, but not over the seamount. In contrast, Pacific red snapper was a permanent resident near the seamount, but was recorded as dominant near the seamount only during winter and spring. Differences among sites in the densities of fish assemblages on hard substrates exist as a consequence of habitat heterogeneity, fish mobility, behavior, and food supply (Letourneur, 1996; Tolimieri et al., 1998). Fish studies in adjacent areas found differential specific compositions by site (Arreola, 1998; Aburto, 1999; Jiménez, 1999). Migratory species, such as marlin (Tetrapturus audax), sailfish (Istiophorus platypterus), and mahi-mahi (Coryphaena hippurus), common in sport fishing near the seamount, were not observed in our surveys, probably because their speed and the highly developed lateral line and sharp vision could detect our presence. However, these species were well represented in the study area in other studies (Aguilar et al., 1993; Abitia et al., 1997, 1999), and are typically caught by sport fishermen during summer and fall. ACKNOWLEDGEMENTS Thanks to CIBNOR and Consejo Nacional de Ciencia y Tecnología (CONACyT) for funds to complete our study; also to Instituto Politécnico Nacional (COFAA and EDI) for fellowships to F.G.-M. and F.J.G.-S. This study was part of two projects: “Pelagic communities in the lower Gulf of California” and “Fish structure in the Espiritu Santo Island and Espiritu Santo Seamount in the lower Gulf of California.” Editorial staff at CIBNOR improved the English text.

LITERATURE CITED Abitia, C. L. A., M. F. Galván, and R. J. Rodríguez. 1997. Food habits and energy values of prey of striped marlin Tetrapturus audax off the coast of Mexico. Fish. Bull. 95: 360–368. _________, _______________, S. F. J. Gutiérrez, R. J. Rodríguez, P. B. Aguilar, and H. A. Moehl. 1999. Diet of blue marlin Makaira mazara of the coast of Cabo San Lucas, Baja California Sur, Mexico. Fish. Res. 44: 95–100. Aburto, O. M. 1999. Relaciones entre la distribución y la diversidad con respecto al hábitat de la ictiofauna arrecifal de Los Islotes, B.C.S., México. MS thesis, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur. 71 p. Aguilar, P. B., C. L. A. Abitia, A. J. De La Cruz, and R. J. Rodríguez. 1993. On the presence of young sailfish Istiophorus platypterus (Shaw and Nodder, 1972) (Osteichthyes: Istiophoridae) in Cabo San Lucas, B.C.S. Mexico. Rev. Biol. Trop. 42: 391–392. Almenara-Roldan, S. C. 2000. International demand of ornamental species of the Gulf of California. Pages 39–47 in O.O. Aburto and O.C.A. Sanchez. Reef resources of the Gulf of


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California. Management strategies for the marine ornate species. Scripps Institution of Oceanography, La Jolla and Universidad Autónoma de Baja California Sur Press, Baja California Sur. Allen, G. R. and D. R. Robertson. 1994. Fishes of the tropical eastern Pacific. University of Hawaii Press, Manoa. 332 p. Alvarez-Borrego, S. and R. A. Schwartzlose. 1979. Masas de agua del Golfo de California. Cien. Mar. 6: 43–63. Amador, A. B., C. A. Trasviña, A. M. Muhlia, and E. M. L. Argote. 2003. Influence of the EBES Seamount and the Farallon Basin on coastal circulation in the Gulf of California, Mexico. Geof ís. Int. 42: 407–408. Arreola, R. L. 1998. Diversidad de peces de arrecife en la region de La Paz, B. C. S., México. MS thesis, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur. 83 p. Blaber, S. J. M. 1985. The ecology of fishes of estuaries and lagoons of the Indopacific with particular reference to Southeast Africa. Pages 247–266 in A. Yáñez-Arancibia. Fish community ecology in estuaries and coastal lagoons: Toward an ecosystem integration. Universidad Nacional Autonoma de Mexico Press, Mazatlàn. Bohnsack, S. P and S. P. Bannerot. 1986. A stationary visual census technique for quantitatively assessing community structure of coral reef fishes. NOAA Tech. Rep., NMFS. 41: 15 p. Briggs, J. C. 1974. Marine zoogeography. McGraw-Hill Book Company, New York. 475 p. Fowler, A. J. 1987. The development of sampling strategies for population studies of coral reef fishes. A case study. Coral Reef 6: 49–58. Galván, M. F., C. L. A. Abitia, R. J. Rodríguez, E. H. Pérez, and R. H. Chávez. 1996. Lista sistemática de los peces de Isla Cerralvo, Baja California Sur, México. Cien. Mar. 22 : 295– 311. Galzin, R. 1987. Structure of fish communities of French Polynesian coral reef. II: temporal scales. Mar. Ecol. Prog. Ser. 41: 137–322. Hermelin, V. M., J. G. Harmelin, C. Chauvet, C. Duval, R. Galzin, P. Lejeune, G. Barnabe, F. Blanc, R. Chavalier, J. Duclerc, and G. Lasserre. 1985. Evaluation des peuplements et population de poissons. Methodes et problem. Terre Vie 40: 467–539. Horn, M. and L. G. Allen. 1985. Ecología de las comunidades de peces en las bahías y estuarios del sur de California. Pages 169–189 in A. Yáñez-Arancibia. Fish community ecology in estuaries and coastal lagoons: Toward an ecosystem integration. Universidad Nacional Autónoma de México Press, Mazatlán. 654 p. Jiménez, G. S. 1999. Abundancia y estructura comunitaria de peces de arrecife rocoso en la zona de Isla Cerralvo, B. C. S., México. MS thesis, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur. 91 p. Klimley, P. and D. R. Nelson. 1984. Diel movement patterns of the scalloped hammerhead shark (Sphyrna lewini) in relation to El Bajo Espiritu Santo: a refuging central position system. Behav. Ecol. Sociobiol. 15: 45–54. Letourneur, Y. 1996. Dynamic of fish communities on Reunion Fringing Reef, Indian Ocean. II. Pattern of temporal fluctuation. J. Exp. Mar. Biol. Ecol. 195: 31–52. Loya, S. D. H. and A. Escofet. 1990. Aportaciones al cálculo del índice de valor biológico (Sanders, 1960). Cien. Mar. 16: 97–115. Merlín, P. P. and G. S. Ortega. 1997. Estudio sobre la influencia que ejercen las estructuras submarinas en el éxito de pesca de la flota atunera mexicana. Boletín No. 50. Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur. 2 p. Pérez, E. H., C. L. A. Abitia, and M. F. Galván. 1996. Variaciones temporales y espaciales en la estructura de la comunidad de peces de arrecifes rocosos del sur-oeste del Golfo de California, México. Cien. Mar. 22: 273–294. Roberts, C. M. and R. F. Ormond, R. F. 1987. Habitat complexity and coral reef fish diversity and abundance on Red Sea fringing reefs. Mar. Ecol. Progr. Ser. 41: 1–8. Sánchez, O. C., O. J. L. Arreola, O. Aburto, and M. Cortés. 1997. Peces de arrecife en la región de La Paz, B. C. S. Pages 177–188 in R. J. Urban and M. Ramírez (eds.). La Bahía de La

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Paz, investigación y conservación. Universidad Autonoma de Baja California Sur. Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur and Scripps Institution of Oceanograpy, La Jolla. Sanders, H. L. 1960. Benthic studies in Buzzards Bay. III. The structure of the soft-bottom community. Limnol. Oceanog. 5: 138–153. Shannon, E. C. and W. Wienner. 1963. The mathematic theory of communication. University of Illinois Press, Champaign. 119 p. Thomson, D. A., L. T. Findley, and A. N. Kerstitch. 2000. Reef fishes of the Sea of Cortez. University of Texas Press, Austin. 374 p. Tolimieri, N., P. F. Sale, R. S. Nemeth, and K. B. Gestring. 1998. Replenishment of population of Caribbean reef fishes: Are spatial patterns of recruitment consistent through time? J. Exp. Mar. Biol. Ecol. 230: 55–71. Walker, B. W. 1960. The distribution and affinities of the marine fish fauna of the Gulf of California. Syst. Zool. 9: 123–133. DATE SUBMITTED: 6 May, 2003.

DATE ACCEPTED: 9 September, 2004.

Addresses (J.R.-R., A.F.M.-M., V.G.-L.) Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Apdo. Postal 128, La Paz, Baja California Sur 23000, Mexico. (F.G.-M., F.J.G.-S.) Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Apdo. Postal 592, La Paz, Baja California Sur 23000, Mexico.


Appendix 1. Fish species recorded in the study area. i = Espiritu Santo Island, and s = Espiritu Santo Seamount. Sphyrnidae Sphyrna lewini Griffith & Smith, 1838 (s) Urolophidae Urobatis concentricus Osburns & Nichols, 1916 (i, s) Urobatis halleri (Coopers, 1883) (i, s) Squatinidae Squatina californica Ayres, 1859 (i) Elopidae Elops affinis Regans, 1909 (i) Muraenidae Gymnomuraena zebra (Shaw & Nodder, 1797) (i,s) Gymnothorax equatorialis (Hildebran, 1846) (i,s) Gymnothorax castaneus (Jordan & Gilbert, 1882) (i) Muraena lentiginosa Jenyns, 1842 (s) Clupeidae Harengula thrissina (Jordan & Gilbert, 1882) (s) Hemiramphidae Hyporhamphus unifasciatus (Ranzani, 1842) (i) Exocoetidae Fodiator acutus rostratus (Günther, 1866) (s) Holocentridae Myripristis leiognathus Valenciennes, 1855 (i, s) Sargocentron suborbitalis (Gill, 1864) (i) Belonidae Strongylura exilis (Girard, 1854) (i, s) Fistulariidae Fistularia commersonii Ruppel, 1835 (i,s) Serranidae Alphestes immaculatus Breder 1936 (i) Epinephelus acanthistius Gilbert, 1892 (s) Epinephelus analogus Gill, 1864 (i) Epinephelus labriformis (Jenyns, 1843) (i, s) Epinephelus panamensis (Jenyns, 1843) (i, s) Epinephelus itajara (Lichtenstein, 1822) (s) Mycteroperca jordani (Jenkins & Evermann, 1889) (i, s) Mycteroperca rosacea (Streets, 1877) (i, s) Mycteroperca xenarcha Jordan, 1888 (i) Paranthias colonus (Valenciennes, 1846) (i, s) Serranus psittacinus Valenciennes, 1855 (s) Grammistidae Rypticus bicolor Valenciennes, 1846 (i, s) Rypticus nigripinnis Gill, 1862 (i) Priacanthidae Pristigenys serrula (Gilbert, 1891) (i) Apogonidae Apogon retrosella (Gill, 1863) (i, s)

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Appendix 1. Continued. Carangidae Caranx caballus Günther, 1868 (i, s) Caranx sexfasciatus Quoy & Gaimard, 1824 (i, s) Decapturus macarellus (Cuvier, 1833) (s) Naucrates ductor (Linnaeus, 1758) (i) Seriola lalandi Valenciennes, 1833 (i, s) Seriola rivoliana Valenciennes, 1833 (i) Trachinotus rhodophus Gill, 1863 (i) Trachurus symmetricus (Ayres, 1855) (s) Istiophoridae Istiophorus platypterus (Shaw in Shaw and Nodder, 1792) (s) Tetrapturus audax (Philippi, 1887) (s) Makaira mazara (Jordan & Snyder, 1901) (s) Coryphaenidae Coryphaena hippurus (Linnaeus, 1758) (i, s) Lutjanidae Hoplopagrus guntheri Gill, 1862 (i, s) Lutjanus aratus (Günther, 1864) (i, s) Lutjanus argentiventris (Peters, 1869) (i, s) Lutjanus colorado Jordan & Gilbert, 1882 (i, s) Lutjanus guttatus (Steindachner, 1869) (i, s) Lutjanus novemfasciatus Gill, 1862 (i, s) Lutjanus peru (Nichols & Murphy, 1922) (s) Lutjanus viridis (Valenciennes, 1845) (i, s) Gerreidae Gerres cinereus (Walbaum, 1792) (i) Haemulidae Anisotremus interruptus (Gill, 1862) (i, s) Anisotremus taeniatus (Gill, 1862) (i, s) Haemulon flaviguttatum Gill, 1863 (i, s) Haemulon scudderi Gill, 1863 (i) Haemulon sexfasciatum Gill, 1863 (i, s) Sparidae Calamus brachysomus Lockington, 1880 (i) Mullidae Mulloidichthys dentatus (Gill, 1863) (i, s) Kyphosidae Girella simplicidens Osburn & Nichols, 1916 (i) Kyphosus analogus (Gill, 1863) (i, s) Kyphosus elegans (Peters, 1869) (i, s) Sectator ocyurus (Jordan and Gilbert, 1881) (i) Chaetodontidae Chaetodon humeralis Günther, 1860 (i, s) Johnrandallia nigrirostris (Gill, 1862) (i, s) Opistognathidae Opistognathus punctatus Peters, 1869 (i) Ostraciidae Ostracion meleagris Shaw, 1796 (i)


Appendix 1. Continued. Pomacanthidae Holacanthus passer Cuvier & Valenciennes, 1846 (i, s) Pomacanthus zonipectus (Gill, 1863) (i, s) Pomacentridae Abudefduf troschelii (Gill, 1862) (i) Abudefduf declivifrons (Gill, 1862) Chromis atrilobata Gill, 1862 (i, s) Chromis limbaughi Greenfield & Woods, 1980 (i) Microspathodon dorsalis (Gill, 1863) (i, s) Microspathodon bairdii (Gill, 1863) (i) Stegastes flavilatus (Gill, 1863) (i, s) Stegastes leucorus (Gilbert, 1892) (i, s) Stegastes rectifraenum (Gill, 1863) (i, s) Cirrhitidae Cirrhitichthys oxycephalus (Bleeker, 1855) (i, s) Cirrhitus rivulatus Valenciennes, 1855 (i, s) Scorpaenidae Scorpaena mystes (Jordan & Starks, 1895) (i, s) Mugilidae Mugil cephalus Linnaeus, 1758 (i) Mugil curema Cuvier & Valenciennes, 1836 (i) Mugil hospes Jordan & Cuvier, 1896 (i) Labridae Bodianus diplotaenia (Gill, 1863) (i, s) Halichoeres dispilus (Günther, 1864) (i, s) Halichoeres nicholsi (Jordan & Gilbert, 1881) (i, s) Halichoeres chierchiae Caporiacco, 1947 (i, s) Halichoeres semicinctus (Ayres,1859) (i, s) Halichoeres notospilus Günther, 1864 Thalassoma grammaticum Gilbert, 1890 Thalassoma lucasanum (Gill, 1863) (i, s) Xyrichtys pavo (Valenciennes, 1840) (i) Scaridae Nicholsina denticulata (Evermann & Radcliffe, 1917) (i) Scarus compressus (Osburn & Nichols, 1916) (i, s) Scarus ghobban Forsskål, 1775 (i, s) Scarus perrico Jordan & Gilbert, 1881(i, s) Scarus rubroviolaceus Bleeker, 1847 (i, s) Gobiidae Elacatinus punticulatus (Ginsburg, 1938) (i, s) Blenniidae Ophioblennius steindachneri Jordan & Evermann, 1898 (i, s) Labrisomidae Labrisomus xanti (Gill, 1860) (i) Acanthuridae Acanthurus nigricans (Linnaeus, 1758) (i, s) Acanthurus triostegus (Linnaeus, 1758) (i, s) Acanthurus xanthopterus Cuvier & Valenciennes 1835 (i, s) Prionurus punctatus Gill, 1862 (i, s) Zanclus cornutus (Linnaeus, 1758) (i)

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Appendix 1. Continued. Scombridae Acanthocybium solandri (Cuvier, 1831) (s) Euthynnus lineatus Kishinouye, 1920 (i, s) Scomberomorus sierra Jordan & Starks, 1895 (i) Thunnus albacares (Bonnaterre, 1788) (i, s) Balistidae Balistes polylepis Steindachner, 1876 (i, s) Sufflamen verres (Gilbert & Starks, 1904) (i, s) Pseudobalistes naufragium (Jordan & Starks, 1865) (i) Tetraodontidae Arothron meleagris (Bloch & Sneider, 1801) (i, s) Canthigaster punctatissima (Günter, 1870) (i, s) Sphoeroides annulatus (Jennyns, 1842) (i) Sphoeroides lobatus (Jennyns, 1842) (i) Diodontidae Chilomycterus reticulata (Linnaeus, 1758) (i) Diodon hystrix Linnaeus, 1758 (i, s) Diodon holocanthus Linnaeus, 1758 (i, s)

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