CEPHALOPOD PREY OF THE APEX PREDATOR GUILD IN THE EPIPELAGIC EASTERN PACIFIC OCEAN
FELIPE GALVAN-MAGAÑA1 ROBERT J. OLSON 2 NOEMI BOCANEGRA-CASTILLO1 VANESSA GUADALUPE ALATORRE- RAMÍREZ 1
1Centro Interdisciplinario de Ciencias Marinas (CICIMAR) 2Inter-American Tropical Tuna Commission OVERVIEW
Sharks,Sharks, billfishes,billfishes, tunas,tunas, dolphinsdolphins andand mahimahi--mahimahi areare thethe mainmain predatorspredators onon cephalopodscephalopods inin thethe EasternEastern PacificPacific waterswaters (Perrin(Perrin etet al.al. 1973;1973; GalvanGalvan etet al.al. 1985,1989;1985,1989; AbitiaAbitia--CárdenasCárdenas etet al.al. 1997,1998,1997,1998, 1999,1999, 2001;Aguilar2001;Aguilar 1998,1998, MarkaidaMarkaida andand SosaSosa 1998;1998; GalvanGalvan 1999.1999. OlsonOlson andand GalvanGalvan 2002;2002; RosasRosas--AlayolaAlayola etet al.al. 2002)2002) .. TheThe stomachstomach contentscontents ofof thesethese predatorspredators permitpermit toto knowknow thethe distributiondistribution andand abundanceabundance ofof cephalopods,cephalopods, consideringconsidering thethe difficultydifficulty toto catchcatch themthem withwith traditionaltraditional methods.methods. PelagicPelagic predatorspredators havehave shownshown toto bebe thethe mostmost effectiveeffective cephalopodcephalopod samplers,samplers, consideringconsidering theirtheir sizesize mouthmouth andand velocityvelocity theythey cancan capturecapture cephalopodscephalopods ofof allall sizes.sizes. OneOne ofof thethe mainmain problemsproblems toto analyzeanalyze thethe stomachstomach contentscontents inin largelarge predatorspredators isis thethe advancedadvanced digestiondigestion statestate foundfound inin prey.prey. InIn cephalopods,cephalopods, thethe mandiblesmandibles (beaks)(beaks) areare thethe mostmost frequentfrequent structurestructure foundfound inin thethe stomachs,stomachs, becausebecause theirtheir chemicalchemical compositioncomposition isis chitin,chitin, whichwhich isis moremore resistantresistant toto predatorspredators gastricgastric acids.acids. METHODS
TWOTWO DATADATA BASEBASE WEREWERE USEDUSED TOTO ANALYZEANALYZE THETHE INFORMATIONINFORMATION ONON CEPHALOPODSCEPHALOPODS ININ THETHE EASTERNEASTERN PACIFICPACIFIC OCEAN:OCEAN:
19921992--19941994 .. IATTCIATTC PROJECT.PROJECT. TOTO FOUNDFOUND THETHE RELATIONSHIPRELATIONSHIP BETWEENBETWEEN YELLOWFINYELLOWFIN TUNATUNA ANDAND DOLPHINSDOLPHINS ININ THETHE EASTERNEASTERN PACIFICPACIFIC OCEAN.OCEAN. PURSEPURSE--SEINERSSEINERS FROMFROM PANAMA,PANAMA, VENEZUELAVENEZUELA ANDAND MEXICO.MEXICO. 1992-1994 (IATTC PROJECT) 35
Dolphin sets 30 Schoolfish Log sets 25
20
15
10
5
0
-5
-10
-15 -145 -140 -135 -130 -125 -120 -115 -110 -105 -100 -95 -90 -85 -80 -75
Predator Number Spotted dolphin Stenella attenuata 311 manchado Stenella longirostris Spinner dolphin 209 Delphinus delphis Common Dolphin 51 Stenella coeruleoalba Striped dolphin 5 Thunnus albacares Yellowfin tuna 4831 Katsuwonus pelamis Skipjack tuna 1205 Thunnus obesus Bigeye tuna 80 Euthynnus lineatus Black skipjack 100 Auxis spp. Bullet tuna 55 Carcharhinus limbatus Black tip shark 262 Carcharhinus falciformis Silky shark 64 1994-1995 Carcharhinus longimanus Whitetip shark 30 Carcharhinus leucas Bull shark 2 Carcharhinus spp. Other carcharhinids 82 Sphyrna spp. Hammerhead shark 48 Isurus oxyrinchus Mako shark 4 Prionace glauca Blue shark 2 Alopias spp. Thresher shark 12 Nasolamia velox Whitenose sharka 2 Makaira indica Black marlin 25 Makaira mazara Blue marlin 15 Makaira spp. Marlins 18 Tetrapturus audax Striped marlin 8 Istiophorus platypterus Sailfish 49 Coryphaena hippurus Mahi-mahi 545 Acanthocybium solandri Wahoo 235 Elagatis bippinulata Rainbow-runner 48 Total 8298
20032003--2005.2005. PFRPPFRP PROJECT.PROJECT. STABLESTABLE ISOTOPESISOTOPES ANDAND FEEDINGFEEDING HABITSHABITS OFOF PREDATORSPREDATORS ININ THETHE EQUATORIALEQUATORIAL PACIFICPACIFIC OCEAN.OCEAN. PURSEPURSE--SEINERSSEINERS FROMFROM ECUADORECUADOR ANDAND MEXICO.MEXICO. 2003-2005 (PFRP PROJECT) 35 Schoolfish Dolphin sets 30 Log sets
25
20
15
10
5
0
-5
-10
-15 -145 -140 -135 -130 -125 -120 -115 -110 -105 -100 -95 -90 -85 -80 -75 PREDATOR NUMBER PREDATOR NUMBER Alopias pelagicus 3 Auxis rocheii. 12 Carcharhinus 290 Auxis thazard 8 falciformis C. limbatus 5 Euthynnus lineatus 37 C. longimanus 4 Katsuwonus 310 pelamis Isurus oxyrinchus 2 Thunus albacares 937 Sphyrna spp. 1 Thunnus obesus 82 Sphyrna zygaena 3 Thunnus orientalis 7 2003-2005 Sphyraena ensis 2 Stenella attenuata 1 Sphyraena spp. 2 Stenella 1 longirostris Kiphosus elegans 18 Uraspis helvola 2 Kiphosus analogus 10 Seriola lalandi 3 Kiphosus spp. 2 Seriola rivoliana 46 Makaira nigricans 14 Elagatis 171 bipinnulata Istiophorus 1 Decapterus 23 platypterus macarelus Tetrapturus audax 1 Caranx 8 sexfasciatum Tetrapturus 1 Caranx spp. 11 angustirostris Acanthocybium 417 Aluterus monoceros 8 solandrii Lobotes pacificus 18 Aluterus scriptus 9 Corypahena 291 Balistes polylepis 1 hippurus C. equiselis 4 Canthidermis 92 maculatus TOTAL 2 488 2003-2005
1992-1994
s
e
sh
i
f
r
e
h s
e
Ot
m
r
tifo
n
e o
a d
d o i
a e
tr
m e
T
No
ae
id
r
b
m
e
co a
S
gid
n
a
r
e
a
a
C
d
i
t
oe
c
a
o
e
x
c
E
Yellowfin tuna
sta
u s
si
Cr
n
ie
n
a l
s a
a u
g o i
g s s
i
s s
th
a
u
cu e
i
e
t d
d i
o
o si
n
th
e
.
u Do
p
th e
S
T
sp
a ut
0% a 10% n
20% 30%
40%
50% 60% o 70%
80% 90%
g
r
% occurrence % A 2003-2005
1992-1994
s
e
h
s
i
f
er
h
s
t
e
O
m
r
o
f
i
t
n
e
o
a
d
d o i
a e
r
t
m
o
Te
e N
a
id
r
b
m
o
e
c a
S
id
g
n
a
r
e
a
a
C
id
t
e
o
c
o a
Bigeye tuna Bigeye x e
c E
a
t
s
u
r is
C
ns
e i
n
a
s
al
a
u
g
o
i
g
s
s
hi
t u
u
c
ea i
e
d t id
i
o
o s
n
h o
t
e
. D
u
h
p
t
e
p
S T
s
a
t u
0% a
10% n 20%
30% 40% 50%
60% o 70%
80%
90%
g
r % occurrence % A 2003-2005
1992-1994
s
e
h
is
f
r
e
h
s
t
e
O
m
r
o
f
i
t
n
e
o
a d
o id
a e
r
t
m
e
o
T
e N
a
id
br
m
o
e
c a
S
d i
ng
a
r
e
a
a
C
id
t
e
Sharks o
c
o a
x e
c E
a
t
s
u
r is
s C
n
ie
n
la
s
a
a
u
g
o
i
g
is
s
h
t u
a
u
c
e i
e
t id
id
o
o s
n
h o
t
e
. D
u
h
p
t
e
p
S T
s
a ut
0% a
10% n 20%
30% 40% 50%
60% o 70%
80%
90%
g
r % occurrence % A 2003-2005
1992-1994
s
e
h
s
i
f
er
s h
t e
O
m
r
o
f
i
t
n
e
o
d
da
i o
e
a
r
t m
e o
e T
N
a
id
r
b
m
e o
c
da S i
ng
a
r
e
a a
C
id
t
e
o c
Billfishes a o
e x
c
E
a
t
s
u
r is
s
C
n
ie
n
la
s
a
a
u
g
i o
g
s
i
s
h
a u
t
c
e u
i
e
id t
oid s o
h
o n
t
.
e u
D
p
h
e t p
T s
S
a
t u
0% a 10% n
20% 30% 40%
50%
60% 70% o
80%
90%
g
r % occurrence % A
1992-1994
s
e
h
s
i
f
r
e
s
h
t e
O
m
r
o
f
i
t
n e
o a
d
d
i
o
e
a
r
t m
o
e
e
T N
a
d
i
r
b
m
e o
a c
d S i
g
n
a
r e
a a
d C
i
t
e
Wahoo o
c
a
o
e
x
c
E
a
t
s
u
s
i r
s
C
n
e i
n
la s
a a
u g
i
o
g
s
i s
a h u
t
c e
i u
id
d e
i
t
o
s
o
h
o t
n
.
u
e D
p
e h
p
t
T s
S
a
t
0% u a
10% 20% n
30%
40%
50%
60%
70% 80% o
90%
g
% occurrence % r A 2003-2005
1992-1994
s
e
h
s
i
f
er
h
s
t
e
O
m
r
o
f
i
t
n
e
o
a
d
d o i
a e
r
t
m
o
Te
e N
a
id
r
b
m
o
e
c a
S
id
g
n
a
r
e
a
a
C
id
t
e
o
c
o a
x e
c E
Rainbow runnerRainbow a t
s
u
r is
C
ns
e i
n
a
s
al
a
u
g
o
i
g
s
s
hi
t u
u
c
ea i
e
d t id
i
o
o s
n
h o
t
e
. D
u
h
p
t
e
p
S T
s
a
t u
0% a
10% n 20%
30% 40% 50%
60% o 70%
80%
90%
g
r % occurrence % A 2003-2005
1992-1994
s
e
h
s
i
f
er
h
s
t
e
O
m
r
o
f
i
t
n
e
o
a
d
d o i
a e
r
t
m
o
Te
e N
a
id
r
b
m
o
e
c a
S
id
g
n
a
r
e
a
a
C
id
t
e
o
c
o Dolphinfish a
x e
c E
a
t
s
u
r is
C
ns
e i
n
a
s
al
a
u
g
o
i
g
s
s
hi
t u
u
c
ea i
e
d t id
i
o
o s
n
h o
t
e
. D
u
h
p
t
e
p
S T
s
a
t u
0% a
10% n 20%
30% 40% 50%
60% o 70%
80%
90%
g
r % occurrence % A Yellowfin tuna
80 70 60 50 40 30 %Number 20
10 2003-2005 0 1993-1995 Loliginidae Alloposidae o. Octopoda Octopus spp Octopus L.diomedeae o. Teuthoidea Argonauta spp Argonauta Abraliopsis spp Dosidicus gigas Dosidicus Alloposus mollis Alloposus Abraliopsis falco Argonauta nouryi Argonauta Ommastrephidae Loligo opalescens Loligo Onichoteuthis spp Japetella diaphana Japetella Mastigoteuthis spp. Mastigoteuthis Octopus rubescens Octopus Argonauta cornutus Argonauta Vitreledonella richardi Vitreledonella Onychoteuthis banksii Onychoteuthis Mastigoteuthis dentata Mastigoteuthis Octopoteuthis deletron Octopoteuthis Tremoctopus violaceus Tremoctopus Ancistrocheirus lesueuri Ancistrocheirus Pholidoteuthis boschmai Pholidoteuthis Thysanoteuthis rhombus Thysanoteuthis Vampyroteuthis infernalis Stenoteuthis oualaniensis Stenoteuthis DELFINES (92-94)
70
60
50
40
30 % number 20 Striped dolphin (5) 10 Spotted dolphin (30) Spinner dolphin (16) Common dolphin (4) 0 f. spp. spp. f. banksii deletron violaceus rhombus f. Loliginidae Tremoctopus oualaniensis o. Teuthoidea Sthenoteuthis Octopoteuthis Onychoteuthis Onychoteuthis Mastigoteuthis Thysanoteuthis Argonauta spp. Dosidicus gigas Dosidicus Abraliopsis spp. Abraliopsis falco Ommastrephidae Thysanoteuthidae 100%
Mastigoteuthis spp. 80% Abraliopsis falco Onychoteuthis banksii Sthenoteuthis oualaniensis 60% Dosidicus gigas F.Ommastrephidae Thysanoteuthis rhombus Octopoteuthis deletron 40% o. Teuthoidea Japetella diaphana Argonauta nouryi 20% Argonauta spp. Octopus rubescens 2003 - 2005 0% 100% Sharks Tunas Billfish Dolphins Ancistrocheirus lesueuri Loliginidae 80% Mastigoteuthis dentata Pholidoteuthis boschmai Onychoteuthis banksii 1992 - 1994 60% Sthenoteuthis oualaniensis Dosidicus gigas Thysanoteuthis rhombus 40% o. Teuthoidea Japetella diaphana Argonauta spp 20% Argonauta cornutus Octopus rubescens
0% Sharks Tunas Dolphinfish Wahoo and billfish SHARKS (92-95) Tremoctopus violaceus 100% Liocranchia reinhardtii Alloposus mollis 80% Mastigoteuthis spp. Abraliopsis falco 60% Pholidoteuthis boschmani Onychoteuthis banksii 40% Sthenoteuthis oualaniensis Dosidicus gigas 20% f. Ommastrephidae Thysanoteuthis rhombus 0% Octopoteuthis deletron o. Teuthoidea Argonauta spp. Argonauta pacifica Thresher (4) Bull shark (2) shark Bull Silky shark (6) Silky shark SHARKS (2003-2005) hammerhead (7) hammerhead Shortfin mako (1) mako Shortfin Blacktip shark (21) shark Blacktip 100% Carcharhinus spp. Carcharhinus (10) Oceanic whitetip shark (2) shark whitetip Oceanic Smooth hammerhead (10) hammerhead Smooth
80% Ancistrocheirus lesueuri Onychoteuthis banksii Stenoteuthis oualaniensis 60% D.gigas o. Teuthoidea 40% Vitreledonella richardi Japetella diaphana Argonauta spp 20% Argonauta cornutus
0% (27) (1) (1) (2) Pelagic Smooth Silky shark Oceanic thresher (1)
hammerhead whitetip shark whitetip Shortfin mako EPICEPHALOPODS 1992-1994
60
50
40
30
% number 20 Wahoo (114) 10 Dolphinfish and others (51) Tunas (306) Shark (30) 0 Loliginidae O. Teuthoidea Argonauta spp Dosidicus gigas Octopus rubescens Argonauta cornutus Onychoteuthis banksii Loliolopsis diomedeae Ancistrocheirus lesueuri Pholidoteuthis boschmai Thysanoteuthis rhombus Sthenoteuthis oualaniensis EPICEPHALOPODS 2003-2005
60
50
40
30 % number 20 Wahoo (114) Dolphinfish and others 10 Tunas (306) Shark (30) 0 Loliginidae rhombus oualaniensis Sthenoteuthis O. Teuthoidea Argonauta spp Thysanoteuthis Dosidicus gigas Dosidicus Octopus rubescens Argonauta cornutus Onychoteuthis banksii Onychoteuthis Loliolopsis diomedeae Loliolopsis Ancistrocheirus lesueuri Ancistrocheirus Pholidoteuthis boschmai MESOPELAGIC CEPHALOPODS 1992-1994
7.0
6.0
5.0
4.0 Dolphins (39) 3.0 Billfish (5) % number 2.0 Tunas (60) 1.0 2003-2005 Sharks (28) 0.0
14 Japetella diaphana spp. richardi reinhardtii Liocranchia
infernalis 12 Vitreledonella Mastigoteuthis
Vampyroteuthis 10 8 6 Wahoo (2)
% number 4 Dolphinfish and other (5) Tunas (95) 2 Shark (2) 0 Japetella diaphana richardi dentata Vitreledonella Mastigoteuthis 30
25Distribution of jumbo squid Dosidicus gigas in the Eastern Pacific Ocean
20
15
10 E
5 LATITUD 0
-5
-10
-15 -140 -130 -120 -110 -100 -90 -80
-20 LONGITUDE Distribution of Sthenoteuthis oualaniensis in the Eastern Pacific Ocean 30
25
20
15
10 LATITUDE 5
0
-5
-10
-15
-20 -140 -130 -120 -110 -100 -90 -80
LONGITUDE Distribution of Onychoteuthis banksii in the Eastern Pacific Ocean 30
25
20
15
10 LATITUDE 5
0
-5
-10
-15
-20 -140 -130 -120 -110 -100 -90 -80
LONGITUDE SUMMARY
• A NUMBER OF 20 CEPHALOPOD SPECIES WERE IDENTIFIED FROM PREDATORS IN THE EASTERN PACIFIC OCEAN (EPO). •BY FREQUENCY OF OCURRENCE, IN 2003-2005 Dosidicus gigas WAS CONSUMED LESS THAN IN 1992-1994. •HOWEVER BY NUMBER OF ORGANISMS, Dosidicus gigas IN 2003-2005 WAS HIGHER IN STOMACHS OF PREDATORS IN THE EPO. •DOLPHINS PREDATE MORE ON MESOPELAGIC SPECIES AS Abraliopsis spp. •SHARKS CONSUME MORE Dosidicus gigas, Sthenoteuthis oualaniensis and Argonauta spp. •THE LARGE PREDATORS IN THE EPO CONSUME MORE EPIPELAGIC THAN MESOPELAGIC CEPAHLOPODS.