Download N e w Measurements of Area and Distance for Islands in the Sea of

Appendix I. I
N e w Measurements of A r e a
and Distance for Islands in t h e
Sea of C o r t e s
R O B E R T W. M U R P H Y
FRANCISCO S A N C H E Z - P I ~ ~ E R O
G A R Y A . POLIS
ROLF L. AALBU
Studies of island biogeography frequently attempt to explain the numbers
and composition of insular biota (e.g., MacArthur and Wilson 1963, 1967; Lack 1976;
Abbott 1983). These investigations involve quantitative, statistical methods using the
number of species as the dependent variable. The independent variables used in the
correlative regression analyses may include island area (A), distance to nearest source
fauna (D), habitat complexity or the number of plant species, elevation, and latitude.
The predictive values from such analyses directly depend on the accuracy of the
measurements of the independent variables.
Several investigations have examined species numbers on islands in the Sea of
CortCs, as summarized in Case and Cody (1983). We measured A and D (to the nearest
larger source fauna) for almost 80 islands in the Sea of CortCs clearly discernable from
Earth Resources Observation Systems (EROS) satellite photographs. However, many
small coastal islands were not measured, such as those at Bahia Coyote in Bahia
Concepci6n, as well as all Pacific coast islands. In addition, we could not locate Isla
Farallon on any photograph. Some islands that do not remain isolated at low tide, or
that cannot be separated on EROS images, have either been combined in the table
(e.g., Islas Los Coronados) or not measured for island area using satellite images (e.g.,
Isla San Luis Gonzaga). Nevertheless, many islands with faunal and floral records
have been measured. The list includes islands associated with the peninsula of Baja
California, both in the Pacific Ocean and the Gulf of California.
For measurements determined from EROS photographs, the error in repeated, direct measurements of D was f 0 . 2 km. Area, A, determined using a digitizing tablet,
varied by less than 3% for the large islands, by about 5% for intermediate sized
islands, and by as much as 60% for small islands. Estimates of A for extremely small
448 Appendixes
islands (<0.2 km2) should be considered tentative, unless specifically surveyed. Final
estimates of A were determined by comparing digitized island shapes with aerial photographs, particularly those in Miller and Baxter (1977), to determine the best digitized replication of island shape, and by comparing relative island size among the
smaller-sized islands. For statistical purposes, it should be noted that all measurements
were made from the same scale (1 : 121,12 l), and thus all are scaled equally and differ
proportionally.
On comparison, we found a surprising lack of correspondence with published values (e.g., Soul6 and Sloan 1966; Case 1975: Gastil et al. 1983). Discrepancies in
measurement of A and D between satellite and published measurements for some
islands were as large as fourfold, and frequently reached twofold. In general, the new
estimates of A were slightly smaller than those previously published. The discrepancies in measurements are not attributable to different scale maps, as evidenced by
numerous shifts in rank order of size. The discrepancies probably result from the
previous estimations of A and D being made from inaccurate navigational maps.
These new measurements may significantly affect the conclusions of previous biogeographic investigations. For example, Gastil et al. (1983) reported San Ildefonso
and San Francisco islands as having equal areas (2.6 km3). Surprisingly, the latter
island supports almost three times as many lizard species as the former (Murphy and
Ottley 1984), an observation previously attributed to island topography (Murphy
1983). Measurements from EROS satellite photographs, however, resulted in estimates of A of 0.6 km2 for San Ildefonso and 1.5 km2 for San Francisco, nearly a
threefold difference. Thus, differences in A alone may adequately explain the variation
in numbers of lizard species on these two islands as a quantification of habitat available to support stable populations of species; explanations of habitat complexity (Murphy 1983) are unnecessary.
Comments on the Table of Data
Completeness
We have attempted to list all islands in the region that have associated biological data.
These include islands that have been remeasured, as well as those that have not. Some
of the smaller islands could not be located on satellite images or in standard gazetteers.
Thus, these islands have no coordinates. The problem is further complicated by the
occurrence of numerous synonyms used for the same island. Our list does not include
many unnamed rocks (e.g., those charted around Isla San Marcos), or named islets
for which there are no biological data. We would appreciate receiving specific island
coordinates obtained via Geographic Positioning Systems (GPS), as well as island
areas and elevations determined through on-site surveys.
A cursory review of the table (Al.l-1) shows many missing data points. As far as
we can determine, no reliable data exist for these missing values.
Island Synonyms
We have attempted to summarize all known synonyms of islands. In summarizing
data, we have discovered many errors in attributing species to particular islands. Thus,
Island Measurements
449
our island-name synonyms reflect biological attributes as well as variances in geographic and map names. In table (Al.11, individual islands may still be listed more
than once. For example, we give one listing for Isla de Altamura and another for Isla
Altamura. The island coordinates indicate that these islands are very close to one
another, but the separate listing by the U.S. Board on Geographic Names suggests the
occurrence of two nearby islands.
Island Areas
Many islands have no estimated areas. This is particularly true for smaller islands
and rocas. However, data are also missing for many larger islands, particularly those
associated with the head of the gulf and in Pacific coast lagoons. In general, we have
avoided making island area estimations from navigational maps.
Latitude and Longitude Coordinates
The latitude and longitude coordinates of most islands were taken from the U.S. Board
on Geographic Names (USBGN). Our on-ground survey found no variance from those
posted on the U.S.Geographic Survey web site (www-nmd.usgs.gov/www/gnis/index.
html). Apart from these coordinates, the specific locations of islands vary from map
to map and may be unreliable to within 5'-10' or more. Most of the previously published island coordinates appear to have been taken from inaccurate maps, the same
maps used to estimate island size and distance. For example, during a trip to the gulf
islands in 2000, one of us (R.W.M.) used a Garman GPS3+ to navigate from San
Esteban to Angel de la Guarda in fog. This GPS unit, which shows maps, indicated
that we were 3.5 km east of the island in the gulf when we were standing on Angel
de la Guarda. In our table of data, we unfortunately found it necessary to use some
previously published coordinates due to the absence of more recently gathered data.
Coordinates given to seconds were taken from the USBGN database, and these appear
to be very accurate. Locations given in degrees and minutes were estimated from
various maps or taken from the literature, and these are likely to be inaccurate to
varying degrees. Among USBGN coordinates, some variation occurs. For example,
the coordinates for lsla Salvatierra are listed as 30°03'00" N, 114"29'00" W, whereas
the synonym Isla Lobos is listed as 30°03'00" N, 114°31'00" W.
Distance to Nearest Faunal or Floral Source
Estimates of distance for the major islands in the gulf are measured from EROS
satellite images and are indicated as such in the table of data. Some estimates of
distance have been taken from other published sources, and we caution against using
these as accurate measures.
Elevations
Considerable variation occurs in published estimates of island elevations. We have
made few direct measurements on our own, but rather repeated commonly published
data.
450
Appendixes
Ocean Depths
Navigational charts differ considerably in ocean depth profiles. For studies of island
biogeography, the most critical issues are (1) were the islands connected to the peninsula during the last (or older) glacial event, and (2) what is the sequence of isolation
for landbridge islands? Isla Carmen has been listed as being both a deep-water island
and a landbridge island, depending on which map is used to determine ocean depths.
DNA sequence data suggest that Carmen is likely a deep-water island (chap. 8).
References
Abbott, I. 1983. The meaning of z in specieslarea regressions and the study of species turnover
in island biogeography. Oikos 41:385-390.
Case, T.J. 1975. Species numbers, density compensation, and colonizing ability of lizards on
islands in the Gulf of California. Ecology 56:3-18.
Case, T.J., and M.L. Cody. 1983. Island Biogeography in the Sea of Cortkz. University of
California Press, Berkeley.
Gastil, R.G.; J. Minch, and R.P. Phillips. 1983. The geology and ages of islands. In: T.J. Case
and M.L. Cody (eds), Island Biogeography in the Sea of Cortkz. University of California
Press, Berkeley, CA; pp. 13-25.
Lack, D. 1976. Island Biology Illustrated by the Land Birds of Jamaica. University of California Press, Berkeley.
Lewis, L., and P. Ebling. 1971. Baja Sea Guide. Miller Freeman Publications, San Francisco,
CA.
MacArthur, R.H., and E.O. Wilson. 1963. An equilibrium theory of insular zoogeography.
Evolution 17:373-387.
MacArthur, R.H., and E.O. Wilson. 1967. The Theoly of Island Biogeography. Princeton University Press, Princeton, NJ.
Miller T., and E. Baxter. 1977. The Baja Book II. Baja Trail Publications, Huntington Beach,
CA.
Murphy, R.W. 1983. The reptiles: origins and evolution. In: T.J. Case and M.L. Cody (eds),
Island Biogeography in the Sea of Cortkz. University of California Press, Berkeley, CA;
pp. 130-158.
Murphy, R.W.; and J. R. Ottley. 1984. Distribution of amphibians and reptiles on Islands in
the Gulf of California. Annals of Carnegie Museum 53:207-230.
SoulC, M., and A.J. Sloan. 1966. Biogeography and distribution of the reptiles and amphibians
on islands in the Gulf of California, Mexico. Transactions of the Sun Diego Society of
Natural Histoly 14: 137-156.
Coronado islet (Roca Medio)
Coronado del Centro (del
Medio)
Coronado del Norte
Coronado del Sur
Los Coronados
Los Coronados
BCN
BCN
BCN
BCN
Laguna Ojo de
Liebre
Laguna San Ignacio
Bahia Asuncion
Cedros
Cedros
Cedros
Cedros
Cedros
Cedros
Cedros
Punta Eugenia
Laguna Ojo de
Liebre
Revillagigedo
Laguna San Ignacio
Rosarito
Guadalupe
Guaddupe
Island Group
Laguna Ojo de
Liebre
Los Coronados
Los Coronados
PO
Claridn (Santa Rosa: San BartolomC)
La Concha
BCS
BCS
BCS
BCN
BCS
BCS
BCS
BCS
BCS
BCS
BCS
BCS
Arena (Ana)
Asuncion (Angulo Rock)
Cedros (Cerros)
Cedros islet A
Cedros islet B
Cedros islet C
Cedros islet D
Cedros islet E
Cedros islet F
Chester islets (Chester rocks)
Choyita (Islote La Choyita)
Pacific Islands
Abaroa
BCS
Adelaida (Elide)
BCN
Adentro (El Zapato, Inner Islet) PO
Afuera (El Toro, outer islet; Isla PO
Extarior)
Alambre, El (Islote El Alarnbre) BCS
Name
State or
Region
Table I. I - I Island measurements
1
1
2.5 total
348
14.58
15.62
Area
(km3)
Latitude
Longitude
Distance
(km)
Peninsula
Mexico
Peninsula
Peninsula
Cedros
Cedros
Cedros
Cedros
Cedros
Cedros
Peninsula
Peninsula
Guadalupe
Guadalupe
D Measured to
142"
205"
50
1204"
12"
227
206
Elevation
(m)
(continued)
Ocean
Depth
(m)
Piedra de San JosC
Piedra Negra (Islote Piedra
Negra)
Pirimide
Rocas Alijos (x3)
Roca de Cuervo
Roca Doble PinLulo
Roca Elefante (Elefante)
Roca Monument0
Roca O'Neal
Roca Partida
Roca Piniculo
Cresciente (Craciente)
Garzas
Guadalupe
La Islita
Los Morros
Magdalena (Santa Magdalena)
Mangrove
Morro Hermoso
Natividad
Natividad North rock
Natividad-Roca Vela (Sail
Rock)
Negro
North Rock
Pelicanos
La Piedra
Name
Table I.I -I (Continued)
Revillagigedo
Revillagigedo
Revillagigedo
Revillagigedo
Guadalupe
Revillagigedo
Revillagigedo
Revillagigedo
Revillagigedo
Guadalupe
Revillagigedo
Laguna San Ignacio
Laguna Ojo de
Liebre
S of El Rosario
Punta Eugenia
PO
PO
BCS
BCS
BCN
BCS
Magdelena
Laguna San Ignacio
Guadalupe
Guerrero Negro
Bahia Tortugas
Bahia Magdalena
Bahia Magdalena
Tortugas
Natividad
Natividad
Natividad
Island Group
BCS
BCS
PO
BCN
BCS
BCS
BCS
BCS
BCS
BCS
BCS
-
State or
Region
Area
(km')
Latitude
Longitude
Peninsula
1
Peninsula
Clari6n
Socorro
Guadalupe
Clari6n
Socorro
Peninsula
Socorro
Peninsula
232
9
Peninsula
D Measured to
<I
Distance
(km)
17"
150"
415
1298
(low)
Elevation
(m)
>365
Ocean
Depth
(m)
w
V1
P
Bahia Santa Maria
SIN
SIN
Tachichilte
Sonora
0.297~ 27"55'00"
Bahia Guaymas
SON
Peninsula
Peninsula
Peninsula
Peninsula
Peninsula
Peninsula
Peninsula
Sonora
27"53'
31°48'
18"45'00"
3 1°49'
2X018'
2X018'
29"47'00"
30°30'00"
27"08'
24"27'00"
Bahia Guaymas
Bahia Guaymas
BCS
Zacatoso
1.2 total
0.4
2.3
6.3 total
28"49'00"
29"ll'OO"
24"52'00"
27"45'00"
0.098~ 27"55'00n
BCB
Todos Santos (S)
1
Cedros
Peninsula
Peninsula
Peninsula
SON
SON
SIN
SON
SON
Magdelena
Revillagigedo
Bahia de Todos
Santos
Bahia de Todos
Santos
Laguna Ojo de
Liebre
BCS
PO
BCN
Sea of Cortis
Alcatraz
Alcatraz
Algadones, de 10s
Algadones
Almagre Chico (Almagres Chiquito)
Almagre Grande (Almagres
Grande)
Altamura. de
Altamura
San Benitos
San Benitos
Bahia Rosario
San Quintin
nr. Bahia Asuncion
Magdelena
BCS
BCS
BCN
BCN
BCS
BCS
San Benitos
BCS
2X018'
19"18'00"
Revillagigedo
PO
1
ca. 31°30'
Santo Thom6s
BCN
20°06'
Guadalupe
PO
San Benito del Centro (Bonito C)
San Benito del Oeste (Bonito W)
San Jer6nimo (San Geromino)
San Martin
San Roque
Santa Margarita (Margarita;
Santa Magdalena)
Santo Domingo
Socorro (Islas de Santo Tomis)
Todos Santos (N)
Rocas del Vapor (Steamboat
Rock)
Rocas La Soledad (Piedra Santo
Thomas)
San Benedicto (Inocentes;
Aiiublada)
San Benito del Este (Bonito E)
R
P
San JosC
BCS
SON
SON
JAL
BCN
BCN
BCN
BCS
SIN
BCS
SON
SON
BCN
BCS
BCS
SIN
SIN
BCN
BCN
JAL
Bahia ~ n i m a sSW
Bajito, El
Ballena
Baredito
Bargo (Barga)
Basacori
Blanca
Blanca ( ~ n i m a Bay)
s
Blanco (Roca Blanca, Islote
Blanco)
Blanco (Blanca, Concepci6n)
Bleditos
Bledos
Bota
Cabeza de Caballo
Cabeza de Natividad
Cabeza
Bahia Concepcidn
nr. Sonora
nr. Sonora
Ventana
Bahia Concepcidn
nr. Sinaloa
Guaymas
Bahia de las
Animas
nr. Danzante
Bahia de las
~nimas
Bahia de las
~nimas
Colorado River
Espiritu Santo
Bahia Guaymas
Angel de la Guarda
Island Group
BCN
State or
Region
Angel de la Guarda (Angel de la
Guardia)
Animas, Las (Las ~ n i m a sSur)
Arboleda
Ardilla
Ave
Bahia Animas NE
Name
Table I. I - I (Continued)
Area
(km3)
Latitude
Longitude
(km)
Distance
La Ventana
Peninsula
La Ventana
Peninsula
Peninsula
Peninsula
Sonora
Peninsula
Peninsula
Espiritu Santo
Peninsula
Peninsula
San JosC
Peninsula
D Measured to
Elevation
(m)
Ocean
Depth
(m)
G
SIN
BCN
BCS
BCS
BCN
BCS
BCS
BCS
SON
BCS
Cerraja
Cerralvo
Cerro Blanco
Cerro La Bufadora
Chapetona (Rasa)
Cholla
San Pedro Mirtir
Coronado
BCN
BCN
BCN
BCS
Coronado (Smith, Smiths)
Coronados (Los Coronados)
Bahia de 10s
Angeles
Coronados
San Felipe
SIN
SON
JAL
SIN
BCN
S of Tiburdn
Cerralvo
Cape Region
Cape Region
Bahia Guayrnas
Carmen
Chivos
Ciari (Ciaris, Siari)
Cocinas (Colorado)
Dauto
Consag (Roca Consag, Roca
Consagracion)
Corm
Coronadito
Cholludo (Lobos, La Foca, Roca SON
Foca)
nr. Mazatldn
Partida N.
Carmen
San JosC
SON
Candelero (Ventana, Leon Dormido)
Cardones
Cardonosa Este (Cardonosa)
Carmen (El Carmen)
Cayo
Ventana
Bahia Guaymas
BCN
Calaveras
Coronado
Peninsula
Coronado
Peninsula
Peninsula
Peninsula
2.61d
Peninsula
Tiburdn
Peninsula
Carmen
Coronados
Ddtil
0. lad
3.09~
2.18~
30"
1.09"
13.94~
0.24~
9.84d
0.85
0.64"artida
N.
6.03~
Peninsula
1 . 5 8 h a n JosC
7.8ad
Peninsula
2.85d
Peninsula
0.06~
La Ventana
8.73d
Peninsula
0.91d
3.33d
283'
100
6"
767"
12b
479"
17b
35
(continued)
P
o
\
in
Bahia Guaymas
Espiritu Santo
Angel de la Guarda
nr. SON
La Ventana
SON
BCS
BCN
SIN
BCN
El Fierro
Flecha
2.79d
0.61d
6.15~
0.61d
Peninsula
La Ventana
Peninsula
Angel de la
Guarda
Peninsula
Encantada
Encantadas
BCN
5.45'
5.76d
0.55~
Encantada
6 . ~ 5 ~ Peninsula
Angel de la
Guarda
1.673~ Sonora
2.61d
Peninsula
1.94d
Tibur6n
Algodones
Encantadas
Encantada
Bahia Concepcidn
San Pedro MBrtir
nr. Mazatlin
Bahia Concepcidn
0 . 7 3 ~ Coronados
1.09~
Peninsula
1.15~
San JosC
9.27"eninsula
0.746~ Peninsula
D Measured to
SON
BCN
BCN
Coyote (El Coyote)
Craveries
Crestdn
La Cueva
Cueva
Danzante
DBtil (Cholludo, Turners;
Turner; Tornero)
Division (Navio; de la Vela)
San JosC
Longitude
La Doble (Algodones)
Encantada East (Bird rock)
Encantada (sometimes referred
to as El Cholludo: but see
above; Incantada)
Encantada Grande (Salvatie~~a
[in error], San Luis, San Luis
Gonzaga [in error])
de Enmedio (Blanca, Pastel)
Espiritu Santo
Estanque (La Vibora, Pond)
BCS
BCN
SIN
BCS
SON
BCS
SON
Coyote (El Partido, El Coyote)
Coronados
Latitude
0.05
BCS
Coronados islet SW (Santiago?)
Island Group
Distance
(km)
Angel de la Guarda
BCS
Name
Area
(km3)
BCN
State or
Region
Table I. I- I (Continued)
Elevation
(m)
Ocean
Depth
(m)
cn
P
Bahia Concepcion
BCS
Guapa (Guapo, Morro Tecomate)
Habana
Hermano del Norte
Hermano del Sur
Huerfanito, El
Huivuilay (Huivulay, Huivulai,
T6bara)
Iguana
El Indio
El Infiernito
Isabel (San Isabela, Isabella,
Gaviotas)
Las Islitas
Islet E of Partida N
Jaltemba
Jorobado
Los Gemelos
nr. Sonora
Colorado River
Angel de la Guarda
BCN
SIN
BCN
BCN
Gemelos W (Gemelitos)
del Giero
Gore (Core)
Granito (Granite)
BCS
BCN
JAL
BCN
SIN
SIN
SIN
NAY
SIN
SIN
BCN
SON
La Ventana
nr. Danzante
Partida N
Tres Marias
nr. SON
Encantadas
Mainland San
Diego
Espiritu Santo
Bahia Concepci6n
Espiritu Santo
nr. Sonora
Los Gemelos
BCS
BCS
BCS
SIN
BCN
Gallina
Gallo (El Gallo)
Gallo
Garrapata
Gemelos E (Gemelitos)
BCS
Monserrate
Monserrat
BCS
BCS
Las Galeras E
Las Galeras W
111°17'
113"Ol'
105"18'00"
113"31'
107"38'00"
108"53'00"
107"33'30"
105"55'00"
114°39'00"
110"01'00"
Gemelitos W.
Peninsula
Peninsula
Angel de la
Guarda
0.46~
0.30'
0.79'
0.85~
1.39~
Nayarit
Peninsula
0.36'
2.12'
Flecha
Peninsula
0 . 5 5 ~ Peninsula
19.39"eninsula
32
0.48'
Peninsula
Espiritu Santo
0.87~
2.1"
Monserrat
Monserrat
Las Galeras
East
Espiritu Santo
2.73'
2.73'
0.30'
25
15"
85"
23"
24"
85"
2ob
2ob
(continued)
35
18'
400
46
27'
R
w
State or
Region
BCN
SIN
SON
BCS
BCN
BCN
SON
SIN
SON
BCS
BCS
BCS
SIN
Gulf
Gulf
Gulf
SIN?
BCN
SIN
SIN
BCS
BCN
Name
Lagartija
de la Lechuguilla (Lechuguilla)
Leon (Santa Catalina)
La Liebre
Llave
La Lobera (Islote La Lobera)
Lobera
Lobos
Lobos (Areo)
Lobos (Gaviota)
Los Islotes
Luz
Macapule (de Macapule, Racapule)
Maria Cleofas
Maria Madre
Maria Magdalena
Mascocahui
Mejia
Melendres
Del Mero
Mestiza (Chuenque)
Miramar (El Muerto, Link)
Table I . I- I (Continued)
Mestiza
Encantadas
nr. Sonora
Angel de la Guarda
Tres Marias
Tres Marias
Tres Manas
La Paz
Espiritu Santo
nr. Mazatldn
W of Is. Salsipuedes
nr. SON
Bahia Guaymas
Bahia Concepci6n
Ventana
Island Group
Area
(km')
Latitude
Longitude
Angel de la
Guarda
Nayarit
Nayarit
Nayarit
Maria Cleofas
Maria Madre
Sinaloa
Peninsula
Partida Sur
Peninsula
La Ventana
Salsipuedes
D Measured to
0.30"eninsula
3.39d
Peninsula
2.Ud
0.06~
0.30~
Distance
(km)
Elevation
(m)
Ocean
Depth
(m)
\O
iil
P
BCN
SON
BCN
BCN
SON
BCS
JAL
BCN
SON
SON
SON
SON
NAY
Partida
Partida Sur
Passavera
Pata
Patos
Pelcino (=Pelicano?)
El Pelicano (Alcatraz, Tassne)
Pelicano
Pelon
Rasa
Peninsula
Angel de la
Guarda
Peninsula
Sonora
Peninsula
Coronado
Peninsula
Colorado River
Bahia Kino
lsabela
Patos
Sonora
Bota
Peninsula
Tibur6n
Sonora
0.48'
1.042~
13.70'
0.12'
2.00'
Ventana
110°52'00"
108"07'00"
108"07'00"
106"30'00"
106"10'00"
111°13'
111°03'00"
1 13"31f
Espiritu Santo
0.881h 27"54'00"
24"49'00"
23"15'00"
22"40'00"
23"OO'OO"
0.038~ 25'44'
19.86~ 25"41f00"
0.156~ 29"04'
Espiritu Santo
Partida N
San Lorenzo Sur
nr. Mazatlin
nr. Nayarit
nr. Mazatlin
nr. Danzante
Bahia Guaymas
Colorado River
Bahia Guaymas
NAY
NAY
BCS
Las Monas Norte
Las Monas Sur
Monserrat (Monserrate, Monserrato, Santa Cruz)
Montapue (Montagne)
Morrito (InglCs. Barra El Morrito)
Negrita
Novilla
Pijaros
Pijaros
Pijaros
Palmito del Verde
Palmito de la Virgen
Pardo (Roca Sur, Los Candeleros Sur)
Partida bird rock
Partida N (Cardonosa, Partida)
JAL
JAL
SON
SIN
SIN
SIN
SIN
BCS
Isabella
Isabella
Monserrat
BCN
Mitlin
Peninsula
Sdsipuedes
Panida N.
Sonora
Peninsula
Bahia Guaymas
Encantadas
Bahia Concepci6n
nr. Sonora
San Lorenzo Sur
Midriff
Bahia Concepci6n
SON
SON
BCN
SIN
BCS
BCS
SIN
BCN
BCN
SON
SIN
BCS
SIN
Rase (Raze, Raza)
de Redo
Requeson (El Reques6n)
de la Risci6n
Sonora
Sonora
Encantada
Grande
Coronado
Peninsula
La Ventana
Sonora
Peninsula
Bahia Concepci6n
Piojo
Bahia Pescador
Mazatlin
BCS
D Measured to
La Pitahaya (Pitahaya, Sin
Nombre)
Pitahaya
Pitayosa
La Poma (Porno, Encantada,
Cantada)
Quevedo
El Racito (Islote El Racito)
Ramon
Rancho
Rasa bird rock
Rasita
Rasa (Raza, La Rasa, La Raza)
Longitude
SIN
NAY
SON
BCN
SIN
SIN
BCN
Latitude
Las Pelonas
la Pefia
Peruano (Peruano Blanca)
Pescador (El Pescador)
de Piedra
de las Piedras
El Piojo (Piojo)
Island Group
Distance
(km)
Name
Area
(km3)
State or
Region
Table 1. I - I (Continued)
Elevation
(m)
(continued)
<2"
400
46'
9'
5'
18'
35
35
Ocean
Depth
(m)
BCN
JAL
BCN
JAL
BCS
Salvatierra (Coloradito, Lobos.
Los Lobos)
San Andres
San Aremar
San Augustin
San Basilio (x3) (Rocas de la
Gaviota)
San Cosme (Roca San Cosme)
BCS
BCN
SIN
BCN
Rocallosa
Saliaca
Salsipuedes (Sal Si Puedes)
BCN
NAY
BCS
BCS
BCS
NAY
BCN
BCS
BCS
BCN
Blanca (Piedra Blanca)
Gonlondrinas
Lobos (San Rafael)
Morena (Morena)
Negra
Negra
Rasa
Roca San Marcia1
Roca Solitaria
Roca Vela (nr. Mejia)
Roca
Roca
Roca
Roca
Roca
Roca
Roca
Roca between Partida N and
Angel de la Guarda
PeninsulaMonserrat
Ventana
Encantadas
San Lorenzo Sur
S. of Monserrat
S. of Monserrat
Angel de la Guarda
Rasa
Angel de la Guarda
Isabella
San Marcos
Santa Catalina
San Jost.
1.45~
1.21-a
3.27d
5.21d
2.97d
Peninsula
Ventana
Peninsula
Miramar
Encantada
San Lorenzo
Norte
19.21"eninsula
3.39d
Peninsula
1.52~
1.58~
19.82~
2.0
0.3
0.36~
Rasa
Peninsula
Peninsula
Peninsula
Angel de la
Guarda
Angel de la
Guarda
Peninsula
Division
10.79~
19.58~
1.2
Parida N
0.61d
400
37'
169"
4 6'
400
18'
18'
4 6'
114'
8"
35"
51"
23"
San JosC
Midriff
San JosC
BCS
BCN
BCS
SIN
San Damian
San Diego
San Esteban
San Francisco
San Ignacio Farall6n (Farallon
de San Ignacio, San Ygnacio
Farallon)
San Ignacio (de San Ygnacio)
San Ildefonso
San Jorge (George)
San Jorge islet-N
San Jorge islet-S
San JosC
San Juan Nepomuceno (San
Juan Nepomuzeno, now a
peninsula)
San Juanito
Tres Marias
San Lorenzo
Gulf
San Lorenzo Norte (Las ~ n i m a s BCN
N, Anima. Roca Blanca)
San Lorenzo Sur (San Lorenzo) BCN
San Lorenzo (La Paz)
BCS
SON
San Luis (Algodones)
San Lorenzo
Espiritu Santo
Los Algodones
San Ildefonso
Bahia San Jorge
Bahia San Jorge
Bahia San Jorge
San JosC
La Paz
SIN
BCS
SON
SON
SON
BCS
BCS
nr. Monserrat
BCS
Name
Island Group
State or
Region
Table I . I - I (Continued)
Area
(b3) Latitude
Longitude
Distance
(km)
Nayarit
Maria Madre
San Lorenzo
Sur
Peninsula
Peninsula
Sonora
Sonora
Sonora
Peninsula
Peninsula
Peninsula
San Cosme
Santa Cruz
San JosC
Peninsula
Tiburdn
San Lorenzo
Sur
San JosC
Peninsula
Sinaloa
D Measured to
Elevation
(m)
Ocean
Depth
(m)
Santa Cruz
BCS
Santa lnes (Santa 1nCz)
Santa Maria
Satispac
Sierra El Negro
Tachichilte (de Tachichilte,
Talchichilte, Tachichite,
Tachichiltic)
Tesobidre
Tecuacahui (A Tunosa)
Tibur6n (del Tibur6n)
Tijeras (Las Tijeras, Roca
Medio)
Timbabichi bird rock
Tio Ram6n
T6bari
Bahia Guaymas
Santa Catalina
SON
SON
SON
SON
BCS
San Pedro Nolasco
San Ramon
San Vicente
San Vincente
Santa Catalina (Catldn, Catalana,
Catalano)
Santa CNZ
Espiritu Santo
Bahia Guaymas
Tibur6n
nr. Danzante
SIN
SIN
SON
BCS
BCS
SON
SON
nr. Sonora
Bahia Santa Maria
BCS
SIN
BCN
SIN
SIN
Santa Ines
nr. Guaymas
San Pedro MBrtir
BCS
SON
JAL
BCN
San Marcos
San Nicolas
San Pedro
San Pedro MBrtir
Bahia San Luis
Gonzaga
San Marcos
Bahia Guaymas
BCN
San Luis Gonzaga (Isla Willard)
29"48'00"
25"29'00"
25"35'00"
1223.53~ 29"OO'OO"
0.025' 25044'33"~
25"30'00"
24"59'00"
30.07"7~13'00"
0.019' 27'56'
1.687
108"49'00"
109"01'00"
112"25'00"
111°13'31"'
10E051'00"
108"04'00"
112"06'00"
110°03'
114"23'00"
1.70~
1.Md
3
Peninsula
Mainland
4.91d
0.5 10'
Sonora
Peninsula
Sinaloa
Sonora
Peninsula
Monserrat
Peninsula
San JosC
Peninsula
Sonora
San Esteban
Lobos
Sonora
Sonora
Peninsula
0.003
(continued)
BCS
SIN
Gulf
NAY
Name
Tortuga (de Tortuga)
Tosacahui
Tres Marias islet A
Tres Marietas (Las Tres
Marietas)
Las Tunas
Tunosa
Venado (La Venado, Algodones)
Venados
La Ventana (Ventana)
de las Viejas
Vinorama
0.235
1.41d
La Ventana
1
Algodones
Sinaloa
Tres Marias
Puerto Vallarta
Tortuga
Island Group
Area
(km3)
28"59'00"
26"42'00"
25"22'OOf'
27"57'00"
113"30'00"
109"31'00"
108"46'00"
111°07'00"
108"05'00"
105"35'
20°43'
24"5 1'00"
109"01'00"
111052'00"
Longitude
25"37'00"
27"26'00f'
Latitude
3.15~
0.1 75
36.30~
26.65d
Distance
(km)
Peninsula
Sonora
Peninsula
San Marcos
D Measured to
120
25
309'
Elevation
(m)
Abbreviations for state or region: BCN, Estado de Baja California (northern state); BCS. Baja California Sur; IAL, lalisco; NAY, Nayarit; PO, Pacific Ocean; SIN, Sinaloa, SON, Sonora
'Data from Lewis and Ebling (1971).
bMeasured by island survey.
'Data from Sea of Cortez Charts (1998). Fish n Map Co. (Arvada, Colorado).
d ~ e a s u r e dfrom EROS satellite photographs.
'Data from Soult and Sloan (1966).
SIN
SIN
SON
SIN
BCN
SON
SIN
State or
Region
Table I . I- I (Continued)
35
1200
Ocean
Depth
(m)