1. No category

CENTRO INTERDISCIPLINARIO
DE CIENCIAS MARINAS
Biological studies on sharks and rays to recommend conservation or
management measures in Baja California Sur
Dr. Felipe Galván-Magaña
2000. What happen with Scalloped hammerhead in the
Gulf of California?
•What biological studies exist in Mexico to apply in
shark fishing regulations or conservation ?
•
Fishing camps
Las Barrancas
Punta Belcher
Punta Lobos
San José del Cabo
Punta Arenas
El Sauzoso
El Pardito
Silky shark: Carcharhinus falciformis
Ages: ♂ 14 : ♀ 16 years
♂142-260 cm TL; age groups: 3-14 years
♀88-230 cm TL; age groups: 2-16 years
Maturity age : 8 years.
Season: Only in Summer
•
♀
D.
gigas
♀ S.maturity
at
180
cm
TL;
♂
at 182 cm TL.
japonicus
22.7%
•
Sexual22.04%
rate 0.6 : 1 (M:H).
•2-9 embryos.
•
♂
Sperm
storage
C. hippurus
7.4%
C. equiselis
7.8%
P. planipes
28.4%
Blue shark: Prionace glauca
Ages 1 to 16 years with 70 to 290 cm TL.
•
Maturity age : ♂ 5-7 and ♁ 7-9 years.
•
Almost all the blue sharks are immature with size from
111-150 cm TL (4-7 years).
•We found a lower growth rate in Baja California than the
NE Pacific Ocean.
•
We foud this shark all year round.
•Sexual rate: 1.6 M:1 H.
•Sexual maturity: ♂ 190 /♁ 200 cm TL).
•Mating and shark born during Summer.
•Gestation: 12 months ( 27-33 embryos) .
•
Scalloped Hammerhead: Sphyrna lewini
Fishing season : Juveniles in Winter (December to february).
•Almost all sharks are immature (65-150 cm TL).
•Bahía de la Paz is a nursery area for this shark.
•
D. gigas
23.3%
Fish rests
25.5%
Unidentified fishes
12.8%
A. affinis
8.1%
To know the poblational size, using the
tagging method.
O. banksii Calculate the time that sharks are in
nursery areas (Bahia de la Paz y
11.8% Mazatlan).
S. japonicus
9.4%
To determine the distance and migration
route.
Mako Shark: Isurus oxyrinchus
F
49 % Coryphaena hippur
Dosidicus gigas 9 %
Opisthonema libertate 10 %
Fishes rests 14 %
Ages from 0 to 18 years with 70 to 290 cm
LT
Maturity age : 7 years ♂ : 15 years ♁.
Species found between 1 to 5 years with
90 to 160 cm TL
Angel shark: Squatina californica
Diplectrum spp.
4.1%
P. margaritatus
6.2%
Orgánic matter
F
10.7%
Fish rests
Season:Winter-Spring
•♀ mature at 74 cm TL; ♂ at 80cm TL
•Embryos number: 4 – 6.
•Mating and born: Summer
•
Using isotopes δ15N y
δ13C
indicate
that
principal food source is
from benthic organisms in
the coastal areas.
67.3%
Whale shark: Rhincodon typus
Las Ánimas
Las Ánimas
Tamaño de avistamiento
IA
RN
FO
LI
CA
DE
Bajo
ElElBajo
Bahía norte
Sin transectos
Los Islotes
BAHÍA DE
L
A PAZ
Bahía centro
Census by sea:
Ruta navegación
Isla Espíritu Santo
SanJuan
Juan
San
delalaCosta
Costa
de
Isla
Cerralvo
Bahía sur
Submarino
AZ
LLAAPPAZ
MÉXICO
O
LF
GO
O
FIC
CÍ
PA
Censos aéreos:
With transects
NO
ÉA
OC
Isla San José
1
2
3-10
107°
105°
Tiburón ballena: Rhincodon typus
Season of abundance: May-Jun and Sep-Nov.
•They are segregated by size and sex.
•Bahía de la Paz is a nursery area.
•They feed on different zooplankton species considering their size
•Depending the prey abundance, they use different feeding ways (sucction
• or ram).
•Bahia de Los Angeles (new study area)
•
Muestreos
Zooplankton
Carnívoros
Herbívoros
Omnívoros
13C y
15N
48 hrs a 60º
White shark: Carcharodon carcharias
Ongoing study
•Isla Guadalupe
Population structure
Sexual rate
Residence
Sexual segregation
•Genetic
Population studies
•Dynamic
Migratory movements
(short and large scale)
Rap system,archival tags
•Feeding behavior and C
and N isotopes
•
SITUACION MUNDIAL
Captura dirigida e incidental
•Madurez tardía
• Baja fecundidad
• Declive poblacional
•
CITES (Convención sobre el Comercio
Internacional de Especies Amenazadas de
Fauna y Flora Silvestres) IUCN (Unión
Internacional para la Conservación de la
•
PROFUNDIDAD
Porcentajes
Intervalos de Profundidad
FISHERY ON RAYAS IN THE GULF
OF CALIFORNIA
Age and growth
reproduction, feeding
habits
REPRODUCTION
AGE AND GROWTH
Ancho de Disco
PROJECT WEB PAGE:
WWW.TIBURONESYRAYASCICIMAR.COM
ACKNOWLEDGEMENTS
REPRODUCTION:
 Carcharhinus falciformis (Piloto): Mauricio Hoyos.
 Prionace glauca (Azul): Maribel Carrera.
 Squatina californica (Angel): Elisa Marqueda.
 Sphyrna lewini (Cornuda barrosa): Armando Soria, Marcela Bejarano.
FEEDING HABITS:
 Prionace glauca (Azul): Berenice Aguilar.
 Squatina californica (Angel): Ofelia Escobar.
 Sphyrna lewini (Cornuda barrosa): Nallely Aguilar, Yassir Torres. Colombo Estupiñan, Luis Cedeño
 Alopias pelagicus. Carlos Polo, Marcos Calle, Liliana Rendon, Fabian Pacheco
Isurus oxyrinchus (Mako): Paula Velasco. Hector Erazo
Carcharhinus falciformis (Piloto): Alejandra Cabrera, Linda Barranco, Colombo Estupiñan, Luis Cede
Sphyrna zygaena : Ruth Ochoa
AGE AND GROWTH:
 Carcharhinus falciformis (Piloto): José Antonio Sánchez.
 Isurus oxyrinchus (Mako): Constanza Ribot.
Prionace glauca (Azul): Pilar Blanco
 Sphyrna lewini (Cornuda barrosa): Jorge Zarate.
ECOLOGY:
 Rhincodon typus ( Tiburón Ballena): Dení Ramirez, James Ketchum, Ana Hacohen.
Carcharodon carcharias (Tiburón Blanco) Mauricio Hoyos, Mario Jaime Rivera, Pilar Blanco.
Parasites: Oscar Méndez.