Martín E. Hernández Rivas, Sylvia P. A. Jiménez Rosenberg, Alejandro Hinojosa Medina, Ricardo

Saldierna Martínez y Gerardo Aceves Medina.CICIMAR-IPN

mrivas@ipn.mx

INSTITUTO POLITÉCNICO NACIONALCENTRO INTERDISCIPLINARIO DE CIENCIAS

MARINASDEPARTAMENTO DE PLANCTON Y ECOLOGÍA

MARINA

STUDY AREA

Arriaga Cabrera, L., E. Vázquez Domínguez, J. González Cano, R. Jiménez Rosenberg, E. Muñoz López, V. Aguilar Sierra (coordinadores). 1998. Regiones marinas prioritarias de México. Comisión Nacional para el Conocimiento y uso de la Biodiversidad

Canal de DeweyIsla Natividad

Isla San Benito

Isla Cedros

W116.0 115.0 114.0 113.0 112.0

27.0

28.0

29.0

30.0

Sonora

Pacific Ocean

U .S.N

PuntaCanoas

PuntaBlanca

PuntaBaja

Laguna Manuela

Laguna Ojo de Liebre

Bahía Tortugas

Laguna Guerrero Negro

Punta Eugenia

Canalde Keller

200 m

2000 m

1000 m

STUDY AREA

MATERIAL AND METHODS

The IMECOCAL program has conducted oceanographic expeditions every three months since 1997 to date with the aim to monitor the southern region of the California Current, by means of similar methodology to that implemented for the CALCOFI program. CTD, the CUFES system for fish eggs sampling, and Bongo and Calvet nets have been used as sampling devices.

Fish larvae obtained with oblique bongo tows (60 cm diam. and 500 mesh), were separated and identified to the minimum possible taxon. The sardine larvae identified were grouped into four development stages, namely: preflexion, flexion, postflexion and transformation.

The larval abundance was normalized to 10 m2 sea surface and larval indexes were computed. The census estimations were adjusted to the area in order to prevent that the area factor would augment them.

-118 -116 -114 -112 -110 -108 -10622

24

26

28

30

32

IMECOCAL 1997-2002Sardinops sagax

Average

0 1 10 20 30 40 50

-118 -116 -114 -112 -110 -108 -10622

24

26

28

30

32

IMECOCAL 1997-2002Sardinops sagax

0 1 10 50 100 250 500

Tota l

RESULTS

Distribution and Abundance of Sardinops sagax larvae2003 is not included because the low numbers of larvae

0

7

2 2

4

4

10

23

4

8

4

6

1

5

1

3

4

10

3

01

00

2

4

6

8

10

12

9710

9801

9804

9807

9810

9901

9904

9908

9910

0001

0004

0008

0010

0101

0104

0107

0110

0201

0204

0207

0210

0301

0304

0307

0310

Positive stations in Sebastián Vizcaíno Bay

The red dot indicate only 3 sampled stations in this cruise

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

9710

9801

9804

9807

9810

9901

9904

9908

9910

0001

0004

0008

0010

0101

0104

0107

0110

0201

0204

0207

0210

0301

0304

0307

0310

Po

sitiv

e S

tatio

ns

Cruise

IMECOCAL Index

IMECOCAL INDEX, % POSITIVE STATIONS

ONLY 3 STATIONS SAMPLED IN THIS CRUISE

0.000.050.100.150.200.250.300.350.400.450.50

9801 9901 0001 0101 0201 0301

Positi

ve S

tatio

ns

Winter Cruises

IMECOCAL Index-January

0.000.050.100.150.200.250.300.350.400.450.50

9807 9908 0008 0107 0207 0307

Positi

ve S

tatio

ns

Summer Cruises

IMECOCAL Index-July

0.000.050.100.150.200.250.300.350.400.450.50

9710 9810 9910 0010 0110 0210 0310

Positi

ve S

tatio

ns

Fall Cruises

IMECOCAL Index-October

0.000.050.100.150.200.250.300.350.400.450.50

9804 9904 0004 0104 0204 0304

Positi

ve S

tatio

ns

Spring Cruises

IMECOCAL Index-April

IMECOCAL INDEX BY MONTH

-4

-2

0

2

4NORTH ( 0 - 50 m )

T a

no

ma

ly (

o C )

-4 -2 0 2 4

ME

I

1998 2000 2002 2004 2006 2008 -4

-2

0

2

4

T a

no

ma

ly (

o C )

SOUTH ( 0 - 50 m )

-4 -2 0 2 4

ME

I

R. Durazo, et al. 2005

120 118 116 114 112

Longitud W

24

26

28

30

32

Lat

itu

d N

Región 2

Región 1

Durazo et al., 2005

TEMPERATURE

120 118 116 114 112

Longitud W

24

26

28

30

32

Lat

itu

d N

Región 2

Región 1

Durazo et al., 2005

SALINITY

0

10000

20000

30000

40000

50000

60000

70000

9710

9801

9804

9807

9810

9901

9904

9908

9910

0001

0004

0008

0010

0101

0104

0107

0110

0201

0204

0207

0210

0301

0304

0307

0310

LARV

AL

IND

EX 1

0^6

IMECOCAL CRUISES

Sardinops sagax

LARVAL INDEX BY CRUISE IN S. VIZCAÍNO BAY

CONCLUSIONS

• The tendency of de abundance of sardine larvae en Sebastián Vizaíno area is to decrease.•The presence of larvae of temeprate stock was more abundant during all period.•The larvae of cold stock was found in the spring IMECOCAL cruises, increased from April 1999 to April 2002, after that dissapear in the area.•The IMECOCAL Index (N+/NT), in general decreased from August 1999 to October 2003.