S-189 Cruise Report

Cruise Report S-189

Scientific data collected aboard SSV Robert C. Seamans

San Diego – La Paz – Puerto Vallarta 16 October 2003 – 24 November 2003

Sea Education Association Woods Hole, Massachusetts

To obtain unpublished data, contact the SEA data archivist: Erik Zettler, Science Coordinator Sea Education Association P.O. Box 6 Woods Hole, MA 02543

Phone: 508-540-3954 ext. 29 800-552-3633 ext. 29 Fax: 508-457-4673 E-mail: [email protected] Web: www.sea.edu

2 Table of Contents

Ship’s Company 4 Introduction 5 Table 1: Student research projects, cruise S-189 6 Table 2: Academic lectures and activities 7 Data Description 8 Figure 1: S-189 cruise track 8 Figure 2: Locations of oceanographic sampling stations 9 Table 3: Oceanographic sampling stations 10 Table 4: Surface station data 15 Table 5: Neuston net tow data 16 Table 6: Hydrocast bottle data 18 Scientific Results: Student Abstracts 22 Figures 3-25: Selections from student research papers Tables 7,8: Selections from student research papers

3 Ship’s Company

SSV Robert C. Seamans, Cruise S-189 Nautical Staff Elliot Rappaport Captain Pamela Coughlin Chief Mate Ben McKee Second Mate Carter Cassel Third Mate Gray Stockmayer Engineer Jonathan Cedar Assistant Engineer Christopher Wang Steward Gillian Faustine Deckhand

Scientific Staff Kara Lavender Chief Scientist Jim Watkins First Assistant Scientist Sarah Piwinski Second Assistant Scientist Cina Loarie Third Assistant Scientist

Students Natalie Ashton Northeastern University Lauren Burk University of North Carolina, Chapel Hill Katherine Cohn Oberlin College Meredith Costa University of North Carolina, Chapel Hill Kyle Detwiler Princeton University Matthew Fromboluti Carleton College Michael King Colby College Erin Knight Hamilton College Mark Kuske Oregon State University Elizabeth Lovelock University of Pennsylvania Coleen MacNally Hamilton College Brenna Mahoney Cornell University Michael-Ryan McCabe Georgia Institute of Technology Kristen Mitchell Eckerd College Laura Nelson Dartmouth College Sara Nelson University of Arizona William Palmieri St. Olaf College Celeste Plautz Lake Forest College Kathleen Ryan Williams College Patrick Schmidt Villanova University Emily Warrener Earlham College

Visitors Raymundo Avendaño Ibarra IPN-CICIMAR, Mexico Víctor Andrés Levy Pérez IPN-CICIMAR, Mexico Andrea Levy de la Torre La Paz, Mexico

4 Introduction

This report outlines the academic program and shipboard research activities of SEA Semester S-189 aboard the SSV Robert C. Seamans from 16 October 2003 to 24 November 2003. It includes a summary of the oceanographic data collected and the scientific results from student research projects. The information presented here is a preliminary analysis of data collected during S-189. It is not intended to represent final interpretation of the data and should not be excerpted or cited without written permission from SEA. Cruise S-189 departed from San Diego, CA on 16 October 2003 after a rigorous six- week academic shore component in Woods Hole, MA. On shore, students investigated oceanographic topics in the scientific literature and completed written proposals for their research at sea. Shipboard, the sampling program was designed to carry out these student research projects which span the four major disciplines of oceanography – physical, chemical, biological, and geological oceanography (Table 1). Student research efforts culminate in a written paper and an oral presentation to the ship’s company. Abstracts and selected figures from student research papers are included in this report, and the complete student research papers from cruise S-189 are available upon request from SEA. In addition to the formal scientific research and academic activities (Table 2) onboard, we were continually amazed by what we observed from the deck. Throughout our journey of 2812 nautical miles we observed fin whales just off the stern, dolphins in the bow wake visible only by bioluminescence, and a squid feeding frenzy illuminated by the deck lights during a nighttime sampling station. During our port stop in La Paz, Mexico we made many new friends during a reception dockside aboard the Seamans. Students were excited to meet scientists from the local research institutions such as IPN-CICIMAR, and we all enjoyed one of many incredible La Paz sunsets. For the second leg of the trip we were fortunate to be joined by observers and visiting scientists Víctor Andrés Levy Pérez and Raymundo Avendaño Ibarra from IPN-CICMAR, and visiting student Andrea Levy de la Torre. No sooner had we departed Bahía de La Paz than our visitors became fully-participating members of the ship’s community, from taking turns at the helm to giving us an overview of research activities of the Sardine Group at CICIMAR. The excellent leadership of the staff, creativity and energy of the students, and enthusiasm and friendship of our visitors made S-189 a success both scientifically and personally. A heartfelt thanks to all aboard.

Kara Lavender Chief Scientist, S-189

5 Table 1: Student research projects, cruise S-189.

Title Student Investigators

A Comparative Sediment Analysis of the California Natalie Ashton Continental and Baja Peninsula Borderlands in the Eastern Pacific

Myctophid Distribution According to Temperature and Tootsie Burk Salinity along the S-189 Cruise Track

A Compositional Analysis of Sediments in the California Michael King Bight and Coastal Baja Liz Lovelock

Comparison of Gravity Cores in the Southern California Erin Knight Bight and the Gulf of California

Diel Vertical Migration of Marine Copepods in the Coleen MacNally Eastern Pacific Ocean in Relation to Size and Color Meredith Costa

What Determines the Extent of Zooplankton Vertical Brenna Mahoney Migration? An Examination of Thermocline Limitation on Copepod Diel Migration

The Thermohaline Structure of the Ensenada Front and Mike McCabe Surrounding Current Systems Meara Ryan

Ocean Profiling: Phosphate and Oxygen in the Eastern Kristen Mitchell Pacific along Baja California and in the Gulf of California Kat Cohn

The Oxygen Minimum Zone and its Effect on the Laura Nelson Habitation Depths of Zooplankton in the Eastern Tropical Kyle Detwiler Pacific

An Examination of the Currents of the Southern Sara Nelson California Bight during October 2003 Mark Kuske

The Influence of the Island Mass Effect on the Vertical William Palmieri Distribution of Phytoplankton in the Eastern Pacific Matthew Fromboluti Ocean

Zooplankton Biomass Density and Diversity Observed Celeste Plautz from San Diego, CA to Puerto Vallarta, Mexico

The Effects of Island Masses on Current Flow in the Patrick Schmidt Eastern Pacific

A Distribution Study of Halobates along the Baja Emily Warrener Peninsula and in the Gulf of California

Distribución de Peces Juveniles Epipelagicos Andrea Levy de la Torre

6 Table 2: Academic lectures and activities.

Date Topic Speaker(s) 18 Oct. Academics at sea E. Rappaport and K. Lavender 20 Oct. Student project introductions Students 21 Oct. Tropical storms E. Rappaport Ongoing Creature features Students Systems chases Students 22 Oct. Reefing the main All hands 23 Oct. Light in the ocean K. Lavender 24 Oct. Data discussion groups Students and Asst. Scientists 25 Oct. Line chase Students 27 Oct. Sound in the ocean S. Piwinski 28 Oct. Nautical science Q&A E. Rappaport and Students 29 Oct. Lab practical exam Students 30 Oct. Stars E. Rappaport 31 Oct. Data discussion groups Students and Asst. Scientists 1 Nov. Bosunry B. McKee 7 Nov. Data discussion groups Students and Asst. Scientists 8 Nov. Anchoring E. Rappaport 10 Nov. Ships and traffic E. Rappaport 11 Nov. Oceanography in the Pacific J. Watkins 12 Nov. Oceanography Q&A C. Loarie 13 Nov. Career paths of sailors E. Rappaport and Mates 14 Nov. Research by the Sardine Group at V. A. Levy Pérez and IPN-CICIMAR R. Avendaño Ibarra 17 Nov. Latitude by Polaris P. Coughlin 18 Nov. Student research project presentations Students 19 Nov. Student research project presentations Students 20 Nov. Measuring ocean circulation with floats K. Lavender 21 Nov. Science sum-up K. Lavender Buoy chase All Hands 22 Nov. Mission: Operation CON GANAS Students

7 Data Description

This section provides a record of data collected aboard the SSV Robert C. Seamans during cruise S-189 (U.S. State Department Cruise 2003-042), which departed from San Diego, CA and transited the Southern California Bight, the eastern Pacific offshore of Baja California, and the Gulf of California, en route to Puerto Vallarta, Mexico (Figure 1).

Figure 1: S-189 cruise track plotted from hourly positions.

During the six week voyage we collected samples or data at 87 discrete oceanographic stations (Figure 2, Table 3), surface samples at 39 locations (Figure 2, Table 4), and we continuously sampled water depth and sub-bottom profiles (CHIRP system), upper ocean currents (Acoustic Doppler Current Profiler, or ADCP), and sea surface temperature, salinity and in vivo fluorescence (seawater flow-through system). This report summarizes sea surface chemical and biological characteristics (Tables 4 and 5), and chemical and biological properties with depth (Table 6). Lengthy CTD, CHIRP, ADCP, and flow-through data are not reported here. All unpublished data can be made available by arrangement with the Sea Education Association (SEA) data archivist (contact information, p. 2).

a) b)

CTD Neuston Net Hydrocast Meter Net 32 Towfish 32 Tucker Trawl Phytoplankton Net CalCOFI Net

27 27

22 22

17 17 -121 -116 -111 -106 -121 -116 -111 -106

c) d)

Shipek Grab Surface Stations Gravity Core 32 32

27 27

22 22

17 17 -121 -116 -111 -106 -121 -116 -111 -106

Figure 2: Locations of oceanographic sampling stations. a) Hydrographic equipment b) Net tows c) Sediment collection d) Surface stations.

9 Table 3: Oceanographic sampling stations.

Local Log Latitude Longitude Cast Station Number Date Time (nm) (N) (W) Depth (m) General Locale CTD S189-002-CTD 18-Oct-03 1804 119.9 33° 08.7 118° 00.2 840 So. Calif. Bight S189-004-CTD 19-Oct-03 1118 177.5 33° 33.0 118° 46.1 432 So. Calif. Bight S189-009-CTD 20-Oct-03 0950 212.2 33° 21.7 119° 00.9 73 So. Calif. Bight S189-011-CTD 20-Oct-03 2150 253.0 32° 43.6 119° 11.1 66 So. Calif. Bight S189-013-CTD 21-Oct-03 1055 283.9 32° 52.9 119° 07.9 1051 So. Calif. Bight S189-015-CTD 21-Oct-03 2148 318.7 32° 58.3 118° 58.2 1193 So. Calif. Bight S189-020-CTD 23-Oct-03 0120 396.5 33° 00.2 119° 00.2 1603 So. Calif. Bight S189-022-CTD 23-Oct-03 1042 434.2 32° 22.4 118° 57.4 238 So. Calif. Bight S189-026-CTD 24-Oct-03 0900 494.9 31° 21.5 119° 38.8 2561 E. Pacific Ocean S189-030-CTD 25-Oct-03 2050 636.5 29° 19.1 118° 23.8 1538 E. Pacific Ocean S189-032-CTD 26-Oct-03 0534 678.0 28° 46.3 118° 14.3 762 E. Pacific Ocean S189-035-CTD 27-Oct-03 0835 837.6 28° 30.3 115° 21.4 220 E. Pacific Ocean S189-037-CTD 27-Oct-03 2215 872.5 28° 02.8 115° 05.8 71 E. Pacific Ocean S189-042-CTD 30-Oct-03 0946 1153.6 24° 29.4 112° 29.4 490 E. Pacific Ocean S189-043-CTD 30-Oct-03 2335 1174.3 24° 15.8 112° 16.5 440 E. Pacific Ocean S189-048-CTD 1-Nov-03 2356 1417.5 23° 39.8 109° 07.9 1523 Gulf of California S189-049-CTD 2-Nov-03 0654 1455.2 24° 05.7 109° 44.0 625 Gulf of California S189-052-CTD 2-Nov-03 2102 1479.6 24° 23.2 110° 01.8 695 Gulf of California S189-057-CTD 8-Nov-03 1134 1642.5 25° 57.4 110° 44.4 977 Gulf of California S189-059-CTD 9-Nov-03 0824 1729.6 26° 13.5 110° 32.7 1681 Gulf of California S189-061-CTD 9-Nov-03 2055 1765.6 26° 01.7 110° 59.4 718 Gulf of California S189-063-CTD 10-Nov-03 1313 1783.7 25° 38.6 110° 52.2 473 Gulf of California S189-065-CTD 11-Nov-03 1123 1847.6 24° 44.3 109° 57.2 593 Gulf of California S189-067-CTD 12-Nov-03 1120 1964.2 23° 30.6 108° 48.8 545 Gulf of California S189-070-CTD 11-Nov-03 1200 2054.9 22° 07.4 109° 00.4 No data Gulf of California S189-072-CTD 14-Nov-03 1210 2126.5 21° 06.7 109° 59.2 598 E. Pacific Ocean S189-075-CTD 17-Nov-03 1128 2416.6 19° 14.6 110° 03.9 596 E. Pacific Ocean S189-077-CTD 18-Nov-03 1041 No data 19° 27.9 108° 24.1 1597 E. Pacific Ocean S189-079-CTD 19-Nov-03 1143 2566.5 19° 44.6 106° 38.1 599 E. Pacific Ocean S189-081-CTD 20-Nov-03 1105 2636.5 20° 09.2 106° 17.5 577 Bahia de Banderas S189-083-CTD 21-Nov-03 1203 2701.0 20° 20.4 106° 21.3 599 Bahia de Banderas S189-085-CTD 22-Nov-03 1656 2774.0 20° 35.6 105° 41.7 544 Bahia de Banderas S189-087-CTD 23-Nov-03 0927 2806.1 20° 35.1 105° 26.5 539 Bahia de Banderas

Hydrocast S189-002-HC 18-Oct-03 1804 119.9 33° 08.7 118° 00.2 840 So. Calif. Bight S189-004-HC 19-Oct-03 1118 177.5 33° 33.0 118° 46.1 432 So. Calif. Bight S189-009-HC 20-Oct-03 0950 212.2 33° 21.7 119° 00.9 73 So. Calif. Bight S189-011-HC 20-Oct-03 2150 253.0 32° 43.6 119° 11.1 66 So. Calif. Bight S189-020-HC 23-Oct-03 0120 396.5 33° 00.2 119° 00.2 1603 So. Calif. Bight S189-026-HC 24-Oct-03 0900 494.9 31° 21.5 119° 38.8 2561 E. Pacific Ocean S189-030-HC 25-Oct-03 2050 636.5 29° 19.1 118° 23.8 1538 E. Pacific Ocean S189-032-HC 26-Oct-03 0534 678.0 28° 46.3 118° 14.3 762 E. Pacific Ocean S189-035-HC 27-Oct-03 0835 837.6 28° 30.3 115° 21.4 220 E. Pacific Ocean S189-037-HC 27-Oct-03 2215 872.5 28° 02.8 115° 05.8 71 E. Pacific Ocean

10 Table 3 continued

Local Log Latitude Longitude Cast Station Number Date Time (nm) (N) (W) Depth (m) General Locale Hydrocast continued S189-048-HC 1-Nov-03 2356 1417.5 23° 39.8 109° 07.9 1523 Gulf of California S189-049-HC 2-Nov-03 0654 1455.2 24° 05.7 109° 44.0 625 Gulf of California S189-052-HC 2-Nov-03 2101 1479.6 24° 23.2 110° 01.8 695 Gulf of California S189-059-HC 9-Nov-03 0824 1729.6 26° 13.5 110° 32.7 1681 Gulf of California S189-061-HC 9-Nov-03 2055 1765.6 26° 01.7 110° 59.4 718 Gulf of California

Towfish CTD S189-017-TF 22-Oct-03 1038 No data 32° 49.3 119° 07.3 0-104 So. Calif. Bight S189-019-TF 22-Oct-03 1400 No data 32° 51.5 119° 02.1 0-77 E. Pacific Ocean S189-069-TF 13-Nov-03 0847 2045.7 22° 18.4 109° 00.9 0-184 E. Pacific Ocean

Neuston Net S189-001-NT 18-Oct-03 1641 77.8 33° 12.6 117° 53.5 0 So. Calif. Bight S189-003-NT 19-Oct-03 0023 134.8 33° 01.4 118° 17.6 0 So. Calif. Bight S189-005-NT 19-Oct-03 1235 177.8 33° 33.5 118° 46.0 0 So. Calif. Bight S189-008-NT 20-Oct-03 0001 200.0 33° 28.1 118° 56.4 0 So. Calif. Bight S189-010-NT 20-Oct-03 1105 213.2 33° 20.8 119° 00.6 0 So. Calif. Bight S189-012-NT 21-Oct-03 0040 253.5 32° 45.7 119° 08.1 0 So. Calif. Bight S189-014-NT 21-Oct-03 1448 291.2 33° 01.5 119° 02.1 0 So. Calif. Bight S189-016-NT 22-Oct-03 0122 321.3 33° 03.6 118° 56.8 0 So. Calif. Bight S189-018-NT 22-Oct-03 1234 458.8 32° 47.4 119° 06.1 0 So. Calif. Bight S189-021-NT 23-Oct-03 0417 400.0 32° 59.6 118° 59.3 0 So. Calif. Bight S189-023-NT 23-Oct-03 1123 431.5 32° 22.0 118° 56.7 0 So. Calif. Bight S189-025-NT 24-Oct-03 0009 476.5 31° 39.4 119° 26.7 0 E. Pacific Ocean S189-027-NT 24-Oct-03 1235 494.9 31° 20.1 119° 36.2 0 E. Pacific Ocean S189-028-NT 24-Oct-03 2326 512.0 31° 03.3 119° 31.9 0 E. Pacific Ocean S189-029-NT 25-Oct-03 1200 602.8 29° 50.9 118° 41.7 0 E. Pacific Ocean S189-031-NT 25-Oct-03 2249 635.0 29° 17.5 118° 23.5 0 E. Pacific Ocean S189-033-NT 26-Oct-03 1158 694.0 28° 43.4 117° 58.7 0 E. Pacific Ocean S189-034-NT 27-Oct-03 0000 793.3 28° 32.3 116° 12.3 0 E. Pacific Ocean S189-036-NT 27-Oct-03 1137 848.2 28° 24.7 115° 10.6 0 E. Pacific Ocean S189-037-NT 27-Oct-03 2320 873.5 28° 02.6 115° 04.7 0 E. Pacific Ocean S189-038-NT 28-Oct-03 1150 908.4 27° 47.3 115° 24.2 0 E. Pacific Ocean S189-039-NT 28-Oct-03 2352 933.0 27° 18.2 115° 08.6 0 E. Pacific Ocean S189-040-NT 29-Oct-03 1158 984.1 26° 35.9 114° 32.0 0 E. Pacific Ocean S189-041-NT 30-Oct-03 0008 1076.5 25° 32.0 113° 17.4 0 E. Pacific Ocean S189-042-NT 30-Oct-03 1136 1155.0 24° 30.5 112° 29.6 0 E. Pacific Ocean S189-043-NT 31-Oct-03 0124 1174.5 24° 16.6 112° 16.9 0 E. Pacific Ocean S189-044-NT 31-Oct-03 1305 1264.6 23° 21.2 111° 03.8 0 E. Pacific Ocean S189-045-NT 1-Nov-03 0010 1297.0 23° 08.1 110° 33.7 0 E. Pacific Ocean S189-046-NT 1-Nov-03 1205 1365.0 22° 59.3 109° 28.4 0 E. Pacific Ocean S189-047-NT 1-Nov-03 2310 1416.8 23° 38.8 109° 07.9 0 Gulf of California S189-050-NT 2-Nov-03 1215 1462.5 24° 12.5 109° 45.3 0 Gulf of California S189-053-NT 3-Nov-03 0027 1488.4 24° 31.1 110° 09.6 0 Gulf of California S189-054-NT 7-Nov-03 0006 1513.5 24° 21.9 110° 28.7 0 Gulf of California

Table 3 continued

Local Log Latitude Longitude Cast Station Number Date Time (nm) (N) (W) Depth (m) General Locale Neuston Net continued S189-056-NT 8-Nov-03 0011 1580.9 25° 17.0 110° 22.6 0 Gulf of California S189-057-NT 8-Nov-03 1233 1642.8 25° 56.4 110° 43.8 0 Gulf of California S189-058-NT 8-Nov-03 2359 1697.4 26° 12.7 110° 27.0 0 Gulf of California S189-060-NT 9-Nov-03 1201 1733.0 26° 08.2 110° 38.5 0 Gulf of California S189-062-NT 10-Nov-03 0002 1756.5 26° 02.7 110° 54.7 0 Gulf of California S189-063-NT 10-Nov-03 1137 1781.2 25° 41.4 110° 51.7 0 Gulf of California S189-064-NT 11-Nov-03 0007 1805.9 25° 20.7 110° 23.5 0 Gulf of California S189-065-NT 11-Nov-03 1207 1847.6 24° 43.8 109° 56.6 0 Gulf of California S189-066-NT 12-Nov-03 0022 1903.4 24° 01.5 109° 30.3 0 Gulf of California S189-067-NT 12-Nov-03 1225 1964.2 23° 30.9 108° 47.2 0 Gulf of California S189-068-NT 13-Nov-03 0014 2028.8 22° 45.6 109° 05.5 0 E. Pacific Ocean S189-070-NT 13-Nov-03 1301 2056.5 22° 06.6 108° 59.7 0 E. Pacific Ocean S189-071-NT 14-Nov-03 0058 2108.0 21° 25.4 109° 40.3 0 E. Pacific Ocean S189-072-NT 14-Nov-03 1107 2124.8 21° 08.7 109° 57.9 0 E. Pacific Ocean S189-073-NT 15-Nov-03 0002 2214.6 19° 48.0 110° 40.8 0 E. Pacific Ocean S189-074-NT 16-Nov-03 2335 2361.5 18° 58.1 111° 02.9 0 E. Pacific Ocean S189-075-NT 17-Nov-03 1208 2416.6 19° 14.5 110° 03.4 0 E. Pacific Ocean S189-076-NT 18-Nov-03 0040 2467.3 19° 30.3 109° 05.3 0 E. Pacific Ocean S189-077-NT 18-Nov-03 1224 No data 19° 26.0 108° 23.7 0 E. Pacific Ocean S189-078-NT 19-Nov-03 0018 2522.7 19° 37.0 107° 25.7 0 E. Pacific Ocean S189-079-NT 19-Nov-03 1230 2575.3 19° 43.8 106° 37.8 0 E. Pacific Ocean S189-080-NT 19-Nov-03 0035 2607.0 19° 57.5 105° 52.3 0 E. Pacific Ocean S189-081-NT 20-Nov-03 1150 2636.6 20° 08.7 106° 17.2 0 E. Pacific Ocean S189-082-NT 21-Nov-03 0023 2675.2 20° 08.5 106° 48.1 0 E. Pacific Ocean S189-083-NT 21-Nov-03 1252 2701.1 20° 20.8 106° 20.8 0 E. Pacific Ocean S189-084-NT 22-Nov-03 0054 2734.0 20° 36.2 105° 53.7 0 E. Pacific Ocean S189-086-NT 23-Nov-03 0408 2796.3 20° 34.1 105° 30.7 0 Bahia de Banderas

CalCOFI Net S189-054-CN 7-Nov-03 0006 1513.5 24° 21.9 110° 28.7 0 Gulf of California S189-056-CN 8-Nov-03 0011 1580.9 25° 17.0 110° 22.6 0 Gulf of California S189-057-CN 8-Nov-03 1233 1642.8 25° 56.4 110° 43.8 0 Gulf of California S189-058-CN 8-Nov-03 2359 1697.4 26° 12.7 110° 27.0 0 Gulf of California S189-060-CN 9-Nov-03 1201 1733.0 26° 08.2 110° 38.5 0 Gulf of California S189-062-CN 10-Nov-03 0002 1756.5 26° 02.7 110° 54.7 0 Gulf of California S189-063-CN 10-Nov-03 1137 1781.2 25° 41.4 110° 51.7 0 Gulf of California S189-064-CN 11-Nov-03 0007 1805.9 25° 20.7 110° 23.5 0 Gulf of California S189-065-CN 11-Nov-03 1207 1847.6 24° 43.8 109° 56.6 0 Gulf of California S189-066-CN 12-Nov-03 0022 1903.4 24° 01.5 109° 30.3 0 Gulf of California S189-067-CN 12-Nov-03 1225 1964.2 23° 30.9 108° 47.2 0 Gulf of California S189-068-CN 13-Nov-03 0014 2028.8 22° 45.6 109° 05.5 0 E. Pacific Ocean S189-070-CN 13-Nov-03 1301 2056.5 22° 06.6 108° 59.7 0 E. Pacific Ocean S189-071-CN 14-Nov-03 0058 2108.0 21° 25.4 109° 40.3 0 E. Pacific Ocean S189-072-CN 14-Nov-03 1107 2124.8 21° 08.7 109° 57.9 0 E. Pacific Ocean S189-073-CN 15-Nov-03 0002 2214.6 19° 48.0 110° 40.8 0 E. Pacific Ocean

Table 3 continued

Local Log Latitude Longitude Cast Station Number Date Time (nm) (N) (W) Depth (m) General Locale CalCOFI Net continued S189-074-CN 16-Nov-03 2335 2361.5 18° 58.1 111° 02.9 0 E. Pacific Ocean S189-075-CN 17-Nov-03 1208 2416.6 19° 14.5 110° 03.4 0 E. Pacific Ocean S189-076-CN 18-Nov-03 0040 2467.3 19° 30.3 109° 05.3 0 E. Pacific Ocean S189-077-CN 18-Nov-03 1224 No data 19° 26.0 108° 23.7 0 E. Pacific Ocean S189-078-CN 19-Nov-03 0018 2522.7 19° 37.0 107° 25.7 0 E. Pacific Ocean S189-079-CN 19-Nov-03 1230 2575.3 19° 43.8 106° 37.8 0 E. Pacific Ocean S189-080-CN 19-Nov-03 0035 2607.0 19° 57.5 105° 52.3 0 E. Pacific Ocean S189-081-CN 20-Nov-03 1150 2636.6 20° 08.7 106° 17.2 0 E. Pacific Ocean S189-082-CN 21-Nov-03 0023 2675.2 20° 08.5 106° 48.1 0 E. Pacific Ocean S189-083-CN 21-Nov-03 1252 2701.1 20° 20.8 106° 20.8 0 E. Pacific Ocean S189-084-CN 22-Nov-03 0054 2734.0 20° 36.2 105° 53.7 0 E. Pacific Ocean S189-086-CN 23-Nov-03 0408 2796.3 20° 34.1 105° 30.7 0 Bahia de Banderas

Meter Net S189-044-MN 31-Oct-03 1235 1163.9 23° 21.2 111° 04.8 400 E. Pacific Ocean S189-067-MN 12-Nov-03 1200 1964.4 23° 30.4 108° 48.1 301 Gulf of California

Tucker Trawl S189-014-TT #1 21-Oct-03 1441 292.0 32° 59.8 119° 03.6 15 So. Calif. Bight S189-014-TT #2 21-Oct-03 1403 291.0 32° 59.8 119° 03.6 150 So. Calif. Bight S189-016-TT #1 22-Oct-03 0147 321.3 33° 02.0 118° 56.8 15 So. Calif. Bight S189-016-TT #2 22-Oct-03 0117 321.1 33° 02.0 118° 56.8 150 So. Calif. Bight S189-042-TT #1 30-Oct-03 1126 1154.9 24° 30.5 112° 29.6 13 E. Pacific Ocean S189-042-TT #2 30-Oct-03 1051 1154.3 24° 30.5 112° 29.6 120 E. Pacific Ocean S189-043-TT #1 31-Oct-03 0116 1174.4 24° 16.6 112° 16.9 18 E. Pacific Ocean S189-043-TT #2 31-Oct-03 0042 1174.4 24° 16.6 112° 16.9 100 E. Pacific Ocean

Phytoplankton Net S189-009-PN 20-Oct-03 0921 212.1 33° 21.7 119° 01.2 0 So. Calif. Bight S189-025-PN 24-Oct-03 0906 494.9 31° 21.5 119° 38.8 0 E. Pacific Ocean

Shipek Grab S189-007-SG 19-Oct-03 1619 184.9 33° 41.4 118° 47.4 907 So. Calif. Bight S189-009-SG 20-Oct-03 0850 212.1 33° 21.6 119° 01.7 54 So. Calif. Bight S189-011-SGA 20-Oct-03 2044 253.0 32° 43.9 119° 12.8 Misfire So. Calif. Bight S189-011-SGB 20-Oct-03 2100 253.6 32° 43.9 119° 12.4 82 So. Calif. Bight S189-035-SG 27-Oct-03 0749 837.6 28° 30.9 115° 21.5 236 E. Pacific Ocean S189-037-SG 27-Oct-03 2201 872.5 28° 03.1 115° 06.0 78 E. Pacific Ocean S189-051-SG 2-Nov-03 1802 1469.0 24° 18.7 109° 51.2 566 Gulf of California S189-055-SG 7-Nov-03 1843 1542.2 24° 33.7 110° 26.5 89 Gulf of California S189-061-SG 9-Nov-03 1913 1755.3 26° 01.9 110° 58.1 776 Gulf of California S189-085-SG 22-Nov-03 1732 2774.0 20° 39.5 105° 41.4 545 Bahia de Banderas S189-087-SG 23-Nov-03 0955 2806.1 20° 35.4 105° 26.8 599 Bahia de Banderas

Table 3 continued

Local Log Latitude Longitude Cast Station Number Date Time (nm) (N) (W) Depth (m) General Locale Gravity Core S189-006-GC 19-Oct-03 1452 184.9 33° 41.0 118° 47.6 907 So. Calif. Bight S189-061-GC 9-Nov-03 1758 1755.5 26° 02.6 110° 57.2 809 Gulf of California

14 Table 4: Surface station data

Station Local Log Latitude Longitude PO4* Chl a* Number Date Time (nm) (N) (W) (µM) (µg/l) SS-001 19-Oct-03 0032 134.8 33° 01.5 118° 17.3 0.119 0.101 SS-002 20-Oct-03 0135 200.0 33° 28.7 118° 56.0 0.148 0.118 SS-003 21-Oct-03 0043 253.5 32° 45.7 119° 08.0 0.249 0.113 SS-004 21-Oct-03 1514 292.0 33° 02.2 119° 01.1 0.105 0.171 SS-005 22-Oct-03 0045 321.0 33° 02.5 118° 56.9 0.225 0.053 SS-006 22-Oct-03 1330 359.9 32° 49.2 119° 04.0 0.268 0.071 SS-007 23-Oct-03 0435 400.0 32° 59.0 118° 59.3 0.220 0.087 SS-008 23-Oct-03 1127 434.2 32° 22.4 118° 56.3 0.206 0.122 SS-009 24-Oct-03 0017 476.5 31° 39.4 119° 20.7 SS-010 24-Oct-03 1241 495.1 31° 20.3 119° 36.0 0.201 0.072 SS-011 24-Oct-03 2350 512.5 31° 02.8 119° 31.6 0.249 0.054 SS-012 25-Oct-03 1206 601.5 29° 50.7 118° 41.5 0.225 0.054 SS-013 26-Oct-03 1201 694.0 28° 43.4 117° 58.6 0.230 0.074 SS-014 27-Oct-03 0000 793.3 28° 32.3 116° 12.2 0.187 0.072 SS-015 27-Oct-03 1140 848.2 28° 24.7 115° 10.5 0.225 0.171 SS-016 28-Oct-03 1159 908.4 27° 47.3 115° 24.1 0.215 0.120 SS-017 29-Oct-03 0010 933.5 27° 17.6 115° 08.3 0.259 0.038 SS-018 29-Oct-03 1207 984.5 26° 35.7 114° 31.7 0.172 0.024 SS-019 30-Oct-03 0025 1077.7 25° 31.3 113° 16.7 0.340 0.014 SS-020 30-Oct-03 1053 1154.4 24° 31.0 112° 29.8 0.196 0.033 SS-021 31-Oct-03 0047 1174.4 24° 16.5 112° 17.6 0.196 0.042 SS-022 31-Oct-03 1307 1264.6 23° 21.2 111° 03.7 0.016 SS-023 1-Nov-03 0015 1297.0 23° 08.0 110° 33.5 0.035 SS-024 1-Nov-03 1210 1365.0 22° 59.3 109° 28.4 0.417 0.040 SS-025 2-Nov-03 1218 1462.5 24° 12.6 109° 45.2 0.499 0.021 SS-026 3-Nov-03 0035 1488.8 24° 31.4 110° 09.8 0.369 0.029 SS-027 6-Nov-03 0010 1513.7 24° 22.1 110° 28.3 0.557 0.131 SS-028 8-Nov-03 0011 1580.9 25° 17.0 110° 22.6 0.468 0.123 SS-029 8-Nov-03 1245 1642.8 25° 56.4 110° 43.8 0.819 0.814 SS-030 9-Nov-03 0001 1698.4 26° 12.7 110° 27.0 0.671 0.478 SS-031 9-Nov-03 1205 1733.0 26° 08.2 110° 38.5 0.557 0.528 SS-032 10-Nov-03 0010 1756.7 26° 02.9 110° 54.4 0.596 0.441 SS-033 10-Nov-03 1140 1781.2 25° 41.3 110° 51.7 0.478 0.419 SS-034 11-Nov-03 1215 1847.7 24° 43.8 109° 56.4 0.453 SS-035 12-Nov-03 1030 1903.6 24° 01.6 109° 30.1 0.500 0.205 SS-036 12-Nov-03 1230 1965.1 23° 30.9 108° 47.1 0.383 0.076 SS-037 13-Nov-03 0025 2018.0 22° 44.9 109° 06.2 0.299 0.050 SS-038 13-Nov-03 1305 2056.5 22° 06.6 108° 59.7 0.284 0.070 SS-039 14-Nov-03 0107 2108.2 21° 25.5 109° 40.8 0.324 0.040

* Blank spaces indicate no data collected

15 Table 5: Neuston net tow data. See Table 1 for station information.

Tow Zoop. Zoop. Plastic Plastic Station Length Temp. Salinity Biomass* Density* Pieces* Pellets* Number (m) (°C) (psu) (ml) (ml/m3) (#) (#) Tar* S189-001-NT 1852 20.3 33.3 S189-003-NT 1852 19.3 33.3 33.0 0.018 0 0 No S189-005-NT 1852 19.9 33.3 4.0 0.002 0 0 No S189-008-NT 1420 18.8 33.3 68.0 0.048 0 0 Yes S189-010-NT 1852 18.2 33.2 10.0 0.005 0 0 Yes S189-012-NT 1852 16.5 33.0 34.0 0.018 0 0 Yes S189-014-NT 2222 17.1 33.1 S189-016-NT 1852 17.9 33.1 S189-018-NT 1111 18.8 33.2 1.8 0.002 0 0 No S189-021-NT 1852 18.5 33.2 11.0 0.006 0 0 No S189-023-NT 1852 18.3 33.2 19.0 0.010 0 0 Yes S189-025-NT 1852 19.5 33.3 11.5 0.006 0 0 No S189-027-NT 2037 19.6 33.3 50.0 0.025 0 0 Yes S189-028-NT 1852 19.5 33.1 100.0 0.054 0 0 Yes S189-029-NT 1852 23.0 33.1 11.0 0.006 0 0 Yes S189-031-NT 1852 20.7 33.1 55.0 0.030 0 0 Yes S189-033-NT 1852 21.7 33.3 20.0 0.011 0 0 No S189-034-NT 1852 21.4 33.3 11.5 0.006 0 0 No S189-036-NT 1852 21.1 33.3 4.5 0.002 0 0 No S189-037-NT 1852 21.1 33.3 13.0 0.007 0 0 No S189-038-NT 1852 21.5 33.3 16.0 0.009 0 0 No S189-039-NT 1852 21.9 33.6 60.0 0.032 0 0 No S189-040-NT 2037 24.9 34.0 8.0 0.004 0 0 No S189-041-NT 2408 24.8 34.0 89.0 0.037 0 0 No S189-042-NT 741 27.9 34.5 S189-043-NT 741 27.2 34.6 S189-044-NT 1852 27.1 34.3 12.0 0.006 2 0 No S189-045-NT 1482 27.0 34.4 31.0 0.021 0 0 No S189-046-NT 1389 29.9 34.6 54.2 0.039 9 0 No S189-047-NT 1852 29.0 34.8 10.0 0.005 0 0 No S189-050-NT 1852 28.9 35.0 95.0 0.051 21 0 No S189-053-NT 1852 28.1 34.9 32.0 0.017 0 0 No S189-054-NT 1852 27.8 35.1 75.0 0.040 0 0 No S189-056-NT 1852 27.3 35.1 180.0 0.097 1 0 No S189-057-NT 1852 25.1 35.3 75.0 0.040 0 0 No S189-058-NT 1852 26.1 35.3 102.0 0.055 1 0 Yes S189-060-NT 1852 26.9 35.3 36.0 0.019 0 0 No S189-062-NT 1852 26.6 35.3 120.0 0.060 0 0 No S189-063-NT 1852 27.2 35.2 36.0 0.019 0 0 No S189-064-NT 1852 27.4 35.0 567.0 0.310 0 0 No S189-065-NT 1852 27.4 35.0 25.0 0.014 0 0 No S189-066-NT 1852 27.0 35.1 180.0 0.097 0 0 No S189-067-NT 1852 27.5 34.6 15.0 0.008 0 2 Yes S189-068-NT 1852 27.4 34.4 10.0 0.005 4 5 No

* Blank spaces indicate no data collected

16 Table 5 continued

Tow Zoop. Zoop. Plastic Plastic Station Length Temp. Salinity Biomass* Density* Pieces* Pellets* Number (m) (°C) (psu) (ml) (ml/m3) (#) (#) Tar* S189-070-NT 1852 28.7 34.4 20.0 0.011 Yes 0 No S189-071-NT 1852 28.4 34.4 23.0 0.012 1 0 No S189-072-NT 1852 28.8 34.5 48.0 0.026 1 0 Yes S189-073-NT 1852 28.9 34.1 32.0 0.017 2 0 No S189-074-NT 1852 28.9 34.2 43.0 0.023 0 0 No S189-075-NT 1852 29.1 34.2 6.0 0.003 0 0 No S189-076-NT 1852 28.3 34.4 25.0 0.014 0 0 Yes S189-077-NT 1852 28.1 34.4 16.0 0.009 17 0 Yes S189-078-NT 1852 28.8 34.1 22.0 0.012 0 0 No S189-079-NT 1852 28.6 34.3 315.0 0.170 0 0 No S189-080-NT 1852 28.6 34.1 100.0 0.054 0 0 No S189-081-NT 1852 28.4 34.4 113.0 0.061 0 0 No S189-082-NT 1852 28.4 34.3 25.0 0.014 2 0 No S189-083-NT 1852 28.7 34.3 12.0 0.006 3 0 No S189-084-NT 1852 28.8 34.4 32.0 0.017 0 0 No S189-086-NT 1852 27.5 34.3 40.0 0.022 0 0 No

* Blank spaces indicate no data collected

Table 6: Hydrocast bottle data. See Table 1 for station information.

Station Bottle Bottle O2* PO4* Chl a* Number Number Depth (m) (ml/l) (µM) (µg/l) S189-002-HC 13 0.0 0.092 0.112 S189-002-HC 12 20.3 6.08 0.012 0.125 S189-002-HC 11 35.1 6.11 0.271 0.612 S189-002-HC 10 55.3 5.45 0.635 0.264 S189-002-HC 9 64.5 5.14 0.684 0.179 S189-002-HC 8 75.1 4.55 0.874 0.111 S189-002-HC 7 99.7 4.19 1.127 0.036 S189-002-HC 6 148.8 3.81 1.217 0.009 S189-002-HC 5 199.2 2.57 1.431 0.005 S189-002-HC 4 298.3 1.93 1.635 0.006 S189-002-HC 3 397.9 1.23 1.740 0.005 S189-002-HC 2 596.3 0.40 2.656 0.005 S189-002-HC 1 794.4 0.30 2.815 0.011 S189-004-HC 13 0.0 0.047 0.206 S189-004-HC 12 25.4 5.94 0.291 0.408 S189-004-HC 11 34.8 5.13 0.669 0.573 S189-004-HC 10 45.0 4.51 0.923 0.237 S189-004-HC 9 54.6 4.51 0.879 0.097 S189-004-HC 8 74.5 4.31 1.247 0.036 S189-004-HC 6 125.3 2.94 1.566 0.007 S189-004-HC 5 198.8 1.75 1.894 0.004 S189-004-HC 4 249.0 1.60 1.840 0.004 S189-004-HC 3 298.1 1.24 2.209 0.004 S189-004-HC 2 348.3 1.06 2.203 0.006 S189-004-HC 1 397.9 0.96 2.442 0.006 S189-009-HC 13 0.0 0.181 0.380 S189-009-HC 11 10.0 6.13 0.112 0.142 S189-009-HC 10 19.2 5.78 0.351 0.203 S189-009-HC 8 29.0 5.36 0.585 0.098 S189-009-HC 6 34.3 5.43 0.585 0.251 S189-009-HC 4 40.7 5.11 0.645 0.126 S189-009-HC 3 44.7 4.94 0.709 0.155 S189-009-HC 2 49.9 4.55 0.764 0.150 S189-009-HC 1 54.7 4.77 0.998 0.089 S189-011-HC 13 0.0 0.122 0.068 S189-011-HC 12 10.1 5.26 0.087 0.090 S189-011-HC 10 20.2 6.17 0.171 0.090 S189-011-HC 8 24.0 5.95 0.092 0.183 S189-011-HC 6 33.8 5.54 0.445 0.213 S189-011-HC 4 44.0 5.04 0.719 0.142 S189-011-HC 2 53.9 4.92 0.669 0.068 S189-020-HC 13 0.0 0.127 0.148 S189-020-HC 12 24.2 5.70 0.142 0.287

* Blank spaces indicate no data collected

Table 6 continued

Station Bottle Bottle O2* PO4* Chl a* Number Number Depth (m) (ml/l) (µM) (µg/l) S189-020-HC 11 49.3 5.21 0.809 0.164 S189-020-HC 10 74.1 4.41 1.018 0.073 S189-020-HC 9 99.0 3.77 1.332 0.018 S189-020-HC 8 173.1 2.49 1.840 0.006 S189-020-HC 7 248.8 1.93 1.665 0.005 S189-020-HC 6 398.2 0.87 2.382 0.005 S189-020-HC 5 596.7 0.56 2.736 0.003 S189-020-HC 4 793.7 0.64 2.970 0.004 S189-020-HC 3 992.0 0.77 2.681 0.005 S189-020-HC 2 1238.8 0.62 2.781 0.004 S189-020-HC 1 1485.9 0.70 0.003 S189-026-HC 13 0.0 0.057 0.063 S189-026-HC 12 24.7 5.72 0.147 0.093 S189-026-HC 11 49.8 5.70 0.595 0.089 S189-026-HC 10 73.5 4.62 1.232 0.097 S189-026-HC 9 89.2 4.55 1.008 0.022 S189-026-HC 8 124.3 3.42 1.292 0.009 S189-026-HC 7 246.8 3.48 2.308 0.004 S189-026-HC 6 494.8 0.60 2.024 0.003 S189-026-HC 5 744.9 0.60 2.133 0.002 S189-026-HC 4 991.3 0.85 2.507 0.002 S189-026-HC 3 1487.4 1.47 2.233 0.002 S189-026-HC 2 1979.7 2.02 1.904 0.001 S189-026-HC 1 2472.5 2.55 1.894 0.001 S189-030-HC 13 0.0 0.112 0.080 S189-030-HC 12 20.1 4.68 0.186 0.094 S189-030-HC 11 39.0 5.12 0.181 0.135 S189-030-HC 10 59.4 5.10 0.132 0.190 S189-030-HC 9 79.1 4.77 0.460 0.089 S189-030-HC 8 109.7 4.29 0.615 0.062 S189-030-HC 7 148.8 2.73 1.312 0.010 S189-030-HC 6 198.7 2.55 1.536 0.005 S189-030-HC 5 397.5 0.84 2.671 0.004 S189-030-HC 3 546.3 0.63 2.616 0.003 S189-030-HC 2 744.6 0.54 2.905 0.003 S189-030-HC 1 993.1 0.58 3.074 0.002 S189-032-HC 13 0.0 0.142 0.072 S189-032-HC 12 15.4 5.34 0.102 0.069 S189-032-HC 11 44.5 6.31 0.092 0.127 S189-032-HC 10 74.4 5.57 0.550 0.182 S189-032-HC 9 113.9 5.25 0.555 0.056 S189-032-HC 8 158.4 4.60 0.983 0.011 S189-032-HC 7 198.8 3.17 1.177 0.007 S189-032-HC 6 228.8 2.70 1.725 0.006

* Blank spaces indicate no data collected

19 Table 6 continued

Station Bottle Bottle O2* PO4* Chl a* Number Number Depth (m) (ml/l) (µM) (µg/l) S189-032-HC 5 268.3 1.91 1.023 0.004 S189-032-HC 3 397.0 0.94 1.780 0.004 S189-032-HC 2 496.1 0.58 2.054 0.003 S189-032-HC 1 645.9 0.51 2.183 0.003 S189-035-HC 13 0.0 0.374 0.294 S189-035-HC 12 15.4 5.38 0.398 0.452 S189-035-HC 11 44.4 4.71 1.028 0.254 S189-035-HC 9 115.0 3.49 1.561 0.041 S189-035-HC 7 193.0 1.62 2.282 0.012 S189-035-HC 5 195.2 1.64 2.258 0.012 S189-035-HC 3 196.7 1.58 2.363 0.011 S189-035-HC 2 198.0 1.60 2.392 0.011 S189-035-HC 1 199.1 1.54 2.205 0.009 S189-037-HC 13 0.0 6.20 0.326 0.163 S189-037-HC 11 10.4 5.51 0.384 0.195 S189-037-HC 9 25.0 5.98 0.417 0.461 S189-037-HC 8 30.4 5.73 0.533 0.452 S189-037-HC 7 35.1 5.37 0.590 0.284 S189-037-HC 6 40.0 4.79 0.686 0.660 S189-037-HC 5 45.1 4.75 0.826 0.452 S189-037-HC 3 50.1 5.02 0.970 0.205 S189-037-HC 1 59.0 4.65 0.946 0.134 S189-048-HC 13 0.0 0.388 0.026 S189-048-HC 12 24.9 4.79 0.326 0.051 S189-048-HC 11 59.5 3.15 1.335 0.126 S189-048-HC 10 99.2 2.05 0.007 S189-048-HC 9 175.0 0.49 2.599 0.003 S189-048-HC 8 250.2 0.53 2.460 0.002 S189-048-HC 7 325.1 0.49 2.508 0.008 S189-048-HC 5 600.7 0.38 2.815 0.002 S189-048-HC 4 794.2 0.44 2.878 0.002 S189-048-HC 3 992.5 0.40 2.959 0.001 S189-048-HC 2 1239.6 0.73 2.844 0.001 S189-049-HC 13 0.0 0.379 0.042 S189-049-HC 12 25.0 5.38 0.571 0.091 S189-049-HC 11 74.5 2.95 1.960 0.033 S189-049-HC 10 99.4 1.87 2.195 0.011 S189-049-HC 9 124.2 0.97 2.503 0.004 S189-049-HC 8 149.2 0.85 2.604 0.007 S189-049-HC 7 199.0 0.47 2.849 0.003 S189-049-HC 6 248.7 0.33 2.820 0.004 S189-049-HC 5 298.1 0.28 2.921 0.004 S189-049-HC 4 397.6 0.29 3.051 0.004 S189-049-HC 3 496.7 0.23 3.200 0.006

* Blank spaces indicate no data collected

Table 6 continued

Station Bottle Bottle O2* PO4* Chl a* Number Number Depth (m) (ml/l) (µM) (µg/l) S189-049-HC 2 596.2 0.25 3.209 0.004 S189-049-HC 1 614.1 0.26 3.142 0.005 S189-052-HC 13 0.0 0.547 0.034 S189-052-HC 12 10.4 4.71 0.460 0.088 S189-052-HC 11 25.3 4.59 0.494 0.144 S189-052-HC 10 39.8 3.83 1.008 0.385 S189-052-HC 9 54.7 3.18 1.301 0.083 S189-052-HC 8 79.6 2.56 1.840 0.027 S189-052-HC 7 99.5 2.16 2.339 0.013 S189-052-HC 6 149.1 1.08 2.609 0.009 S189-052-HC 5 198.8 0.67 2.935 0.004 S189-052-HC 4 248.6 0.77 2.858 0.005 S189-052-HC 3 298.3 0.91 2.964 0.002 S189-052-HC 2 447.2 0.32 3.147 0.002 S189-052-HC 1 620.8 0.30 3.286 0.002 S189-059-HC 13 0.0 0.582 0.450 S189-059-HC 12 30.3 2.36 0.775 0.528 S189-059-HC 11 89.6 4.74 2.295 0.011 S189-059-HC 10 169.8 2.02 2.667 0.007 S189-059-HC 9 248.6 1.11 2.771 0.006 S189-059-HC 8 348.4 0.51 2.855 0.008 S189-059-HC 7 447.4 0.58 2.979 0.006 S189-059-HC 6 546.8 0.55 3.108 0.004 S189-059-HC 5 645.7 0.38 3.256 0.004 S189-059-HC 4 794.8 0.70 3.311 0.005 S189-059-HC 3 943.0 0.52 3.360 0.003 S189-059-HC 2 1091.6 0.58 3.346 0.006 S189-061-HC 13 0.0 0.671 0.539 S189-061-HC 12 24.7 5.18 0.879 0.730 S189-061-HC 11 69.8 3.48 1.785 0.078 S189-061-HC 10 99.4 2.15 2.053 0.025 S189-061-HC 9 149.0 0.81 2.533 0.018 S189-061-HC 8 198.9 1.03 2.726 0.012 S189-061-HC 7 248.8 0.87 2.820 0.005 S189-061-HC 6 322.9 0.32 2.974 0.006 S189-061-HC 5 397.5 0.50 2.974 0.004 S189-061-HC 4 472.1 0.40 2.979 0.005 S189-061-HC 3 546.4 0.58 3.172 0.006 S189-061-HC 2 620.8 0.31 3.182 0.007 S189-061-HC 1 695.2 0.42 3.212 0.006

* Blank spaces indicate no data collected

21 Scientific Results: Student Abstracts

A Comparative Sediment Analysis of the California Continental and Baja Peninsula Borderlands in the Eastern Pacific Natalie Ashton

Abstract The California Continental Borderland and Baja Peninsula Borderlands have very irregular bathymetry with intermittent banks, basins and islands along the coast of California, and the eastern coast of the Baja Peninsula, respectively. The geology of these areas has been widely researched due to their active tectonic states, and it is known that sediment deposition varies greatly within these areas as a result of their irregular bathymetry. The purpose of this study was to analyze the grain size distribution within the two regions, and to see if the grain size and sorting would vary by water depth. Eight Shipek sediment grabs were taken from within these areas, and samples were sieved using 63-4000 µm mesh sieves and quantified by grain size. It was found that the California Continental Borderland has a greater distribution of grain sizes than the Baja Peninsula Borderland, and that water depth is important in quantifying grain size distribution and sorting.

35 Santa Monica Basin S189-007-SG □ = Deep Waters (230 – 907 m) San Diego Figure 3: Locations of Shipek grab 33 Osborn Bank ■ = Shallow Waters (50-89 m) S189-009-SG stations along cruise track S-189. Tanner Bank 31 S189-011-SG Symbol indicates classification by water depth.

) 29 N g

de NW of Cedros Island ( 27 S189-035-SG e

d E of Cedros Island tu

ti S189-037-SG a

L 25 Carmen Basin S189-061-SG W of Isla la Partida 23 S189-055-SG NE of Isla Cerralvo S189-051-SG 21 Puerto Vallarta 19 -123 -120 -117 -114 -111 -108 -105 Longitude (deg E)

100

Figure 4: Cumulative 80 frequency of grain size in 70 e g each sediment sample a t 60 en c r collected at locations in e

P 50 ve i t

Figure 3. a l 40 mu Cu 30

0 -3-2-10123456 Grain Size (phi) Santa Monica Basin Osborn Bank Tanner Bank Northwest of Cedros Is. East of Cedros Is. Northeast of Cerralvo Is. West of Isla la Partida Carmen Basin

22 Myctophid Distribution According to Temperature and Salinity along the S-189 Cruise Track Tootsie Burk

Abstract Different species of the family Myctophidae have previously been found in water masses with specific physical characteristics. To test this hypothesis, myctophid fishes were collected in nighttime neuston net tows along the S-189 cruise track in the eastern Pacific. Also, it was expected that in areas where biomass was expected to be low, like the Gulf of California, the number of different species of myctophids would be high. Five species of myctophids were identified from 90 specimens collected by the placement of photophores on their bodies: Symbolophorus californiensis, Myctophum aurolaternatum, Centrobranchus choerocephalus, Hygophum atratum, and Gonichthys tenuiculus. Distribution maps were then constructed using temperature and salinity measurements of the water, which consequently showed that the five species were concentrated in different water masses with specific characteristics. The amount of zooplankton biomass was shown to have no relationship to the number of different species of myctophids found in an area. This was done by comparing the biomass collected in a neuston tow to the number of different species of myctophids collected in the same tow. Previous studies agree with the distribution of the five species collected and the lack of relationship between biomass levels and number of species found.

w ith myctophids 33 w ithout myctophids Figure 5: Location of nighttime neuston 31 net tows, with symbol indicating

) 29 presence or absence of myctophids in

deg N net sample. 27 ude ( t i 25 Lat 23

19 -123 -120 -117 -114 -111 -108 -105 Longitude (deg E)

120 5

100 4 2)

Figure 6: Zooplankton biomass versus number ^ 80 m / L of species of myctophids collected at individual 3 ass (m

m # of Species

o 60 neuston net stations. ZoopBiomass Bi n o t k

n 2 a l p

o 40 o Z

1 20

0 0 S189- S189- S189- S189- S189- S189- S189- S189- S189- S189- S189- S189- 012-NT 047-NT 028-NT 068-NT 034-NT 071-NT 031-NT 039-NT 025-NT 003-NT 021-NT 041-NT Neuston Stations where myctophids were collected

23 A Compositional Analysis of Sediments in the California Bight and Coastal Baja Michael King and Liz Lovelock

Abstract Eight Shipek grab sediment samples were taken from locations along the coast of California and Baja throughout cruise S-189 on the SSV Robert C Seamans. Samples were sieved by grain size then analyzed for their biogenic composition in sieve class sizes 125, 250 and 500 µm. A test for carbonate in the sediment was done using hydrochloric acid, though a quantitative number for the amount of carbonate could not be obtained. We hypothesized that the majority of the sediment would be terrigenous and that coarser grained sediments would be biogenic. The samples taken in water depths greater than 90 meters were found to be primarily silts, while samples taken at depths less than 90 meters were primarily sand. Due to the large percentage of samples in small size classes that could not be analyzed for composition by hundred counts, a complete picture of sample composition could not be obtained. Supporting our hypothesis, the coarser sediments in the sieve sizes counted were primarily biogenic.

a) Sandy Seive Data

50%

45%

40 %

35%

<63 um 30% 63 um 125 um 25% 250 um 500 um 1000 um 20% 2000 um 4000 um 15%

10%

0% S189-009 S189-011 S189-055 Muddy Sieve Data b) 100%

90%

80%

70%

<63 um 60% 63 um 125 um 50% 250 um 500 um 1000 um 40% 2000 um 4000 um 30%

20%

10%

0% S189-007 S189-035 S189-037 S189-051 S189-061

Figure 7: Percentage of sediment in each size class (number indicates sieve mesh size) for samples that are primarily a) coarse (sandy) and b) fine (muddy).

24 Comparison of Gravity Cores in the Southern California Bight and the Gulf of California Erin Knight

Abstract The sediment record is highly useful in analyzing climate changes and trends. The Southern California Bight and the Gulf of California are two very different geologic areas. The Southern California Bight is an oceanographic hotspot where many water masses converge. The Gulf of California is unique in its seasonal cycles of upwelling and downwelling due to northerly winds. I sampled in both of these areas, specifically the Santa Monica Basin in the Southern California Bight, and the Carmen Basin in the Gulf of California. Analysis of sediment in the two areas collected using gravity cores produced very different results. Sampling in the anoxic Carmen Basin was useful in interpreting decadal time scale changes in the Gulf of California. The largely siliceous composition of Carmen Basin core sediments supports previous studies concerning the high production and seasonality of the area. The Santa Monica Basin core proved useful in studying terrigenous sediment as well as benthic and planktic foraminifera. Carmen Basin sediments were even more useful because of the high quantity of radiolaria and diatoms present.

70 Figure 8: Percent composition Planktic Foraminifera of sediment collected in gravity 60 Benthic Foraminifera core in Santa Monica Basin at n Terrigenous 50 increasing core depth (0 mm itio s

o indicates sea floor). Sediment p 40

m greater than 125µm in o diameter was classified as t C 30 n

e either planktic or benthic c r

e 20 foraminifera, or terrigenous P sediment. 10

0 0 100 200 300 400 500 600 700 799.5 Core Depth (mm)

90 Planktic Foraminifera 80 Benthic Foraminifera Radiolaria n 70 o

i t i Figure 9: Percent composition of s 60 o p

sediment collected in gravity core in m 50 o

Carmen Basin at increasing core C

t 40 depth (0 mm indicates sea floor). cen

r 30

Sediment greater than 125µm in e diameter was classified as either P 20 planktic or benthic foraminifera, or 10 radiolarian. 0

0 2 0 0 5 0 0 0 0 0 0 49 0 0 10 14 2 30 39 4 50 60 70 80 90 014 1 Core Depth (mm)

25 Diel Vertical Migration of Marine Copepods in the Eastern Pacific Ocean in Relation to Size and Color Coleen MacNally and Meredith Costa

Abstract Copepods are one type of marine organism known to undergo diel vertical migration. Pigmentation and size may influence diel vertical migration patterns of marine copepods. We hypothesized that larger, more brightly-pigmented copepods would migrate to the surface at night and return to deeper waters during the day. The study was conducted at numerous locations along the S-189 cruise track from San Diego, CA to Puerto Vallarta, Mexico. A neuston net was towed daily at noon and midnight, and copepod 100 counts were performed on each sample. More copepods were collected at the surface at night than during the day. Greater color variation was found in midnight tows, and transparent copepods were predominant in both noon and midnight tows. More small copepods were found at the surface at night than large copepods. Size and color do play a role in the diel vertical migration of marine copepods, however, other factors such as species variation and location can be influential.

Total Copepod Percentage by Color at Noon and Midnight 30.00 e 25.00 g a t 20.00 noon 15.00 cen

r 10.00 midnight e 5.00 P 0.00

k e e t e d d e e w n e l k n e e in g g o e u lu c u e u r l l p e l r p n n l e b b r la r b - q / a a e r u a - a d r t b e r y g p p d u p e o o h l r g s e o - i r b t d l n a h e r g r t li Color

Figure 10: Percentage of copepods of various colors collected during noon and midnight neuston tows.

70 noon

e 60 l midnight p

m 50 a s 40 of

age 30 ent

c 20 r e

P 10

0 Small Big

Figure 11: Percentage of copepods that were small (< 1 mm) or big (> 1 mm) in length, collected during noon and midnight neuston tows.

26 What Determines the Extent of Zooplankton Vertical Migration? An Examination of Thermocline Limitation on Copepod Diel Migration Brenna Mahoney

Abstract While diel vertical migration is a well-studied behavior, the controlling physical and biological factors that drive the migration remain uncertain. This study hypothesizes that copepod vertical migration is controlled by food abundance and is limited in depth by the thermocline. This study was conducted at two regions along the S-189 cruise track from San Diego, CA to Puerto Vallarta, Mexico. Using neuston and Tucker Trawl nets, samples were taken from the sea surface and above and below the thermocline to yield copepod abundances. A copepod gut fluorescence method was used to indicate amount of feeding at each depth. Findings indicate that feeding is highly variable with little association with abundance levels. Gut fluorescence may not be an appropriate indicator of copepod feeding as it is not a species-specific method. The results of this study support the suggestion that the thermocline is a factor in controlling migration patterns of copepods, as copepod abundance levels were greater above the thermocline than below it.

Temperature (°C) 7 9 11 13 15 17 0

20 Figure 12: Temperature profile at station S189-013-CTD in the Southern California 40 Bight. The CTD profile was used to determine the towing depth for daytime 60

Tucker trawl nets to sample above and 80 )

below the thermocline. m

h ( 100 pt

e D

120

140

160

180

200

100 Figure 13: Copepod 90 abundance (as percent 80 abundance in a zooplankton 70 100-count) at the sea surface, ) % (

e 60 and depths above (13 m in day nc da Day tow (1448) tow; 30 m in night tow) and un 50 b Night tow (0122) a d below (124 m in day tow; 172 o p 40 m in night tow) the thermocline. ope C 30 Samples are from net tows at

20 stations S189-014-TT/NT (day) and S189-016-TT/NT (night). 10

0 Surface Above thermocline Below thermocline Depth Sampled (m)

27 The Thermohaline Structure of the Ensenada Front and Surrounding Current Systems Mike McCabe and Meara Ryan

Abstract The California Current flowing southward converges with the California Countercurrent flowing northward creating the frontal zone known as the Ensenada Front, located at approximately 32°N by 121°W. The Ensenada Front is identified by surface differences in temperature, salinity and fluorescence. To locate the front we used surface data from the flow-through thermosalinograph, as well as near-surface current data from the ADCP. The vertical water mass structure on either side of the front, as well as the front itself, was investigated using CTD profiles and towfish deployments. The data collected on the S- 189 cruise track aboard the SSV Robert C. Seamans illustrate that the Ensenada Front was observed at 32°45.8’ N x 119°12.3’ W. The data also indicate daily frontal zone variability. The water masses on either side of the front were also identified as waters of the California Current to the north and California Countercurrent to the south, affecting the water properties at surface and intermediate depths.

19 5

4.5 18

17 3.5 e r u at

er 16 3 p m e T 2.5 15

14 1.5 Temperature (Deg C) Fluor 13 1 00 41 22 03 44 25 06 47 28 09 51 32 13 54 35 16 57 38 19 00 41 22 03 44 25 06 48 29 10 51 32 13 54 35 16 57 38 19 00 00: 00: 01: 02: 02: 03: 04: 04: 05: 06: 06: 07: 08: 08: 09: 10: 10: 11: 12: 13: 13: 14: 15: 15: 16: 17: 17: 18: 19: 19: 20: 21: 21: 22: 23: 23: 00: 01: 02: Time

Figure 14: Sea surface temperature (pink, left axis) and fluorescence (green, right axis) sampled using the flow-through system along the S-189 cruise track from 21-22 October 2003 in the Southern California Bight. Steep gradients observed around 0244 and 0609 indicate passage across fronts.

Figure 15: Plan view of surface temperature and salinity measured by the flow-through thermosalinograph in the vicinity of the Ensenada Front.

28 Ocean Profiling: Phosphate and Oxygen in the Eastern Pacific along Baja California and in the Gulf of California Kristen Mitchell and Kat Cohn

Abstract Phosphate and oxygen were analyzed in relationship to each other at several stations along the S-189 cruise track. Samples taken at several depths were analyzed for phosphate and oxygen, as well as temperature and salinity. The temperature and salinity data helped define water mass influence on the area and were analyzed together with the phosphate and oxygen profile data. It was hypothesized that in all areas phosphate and oxygen would have an inverse relationship where oxygen decreases with depth as phosphate increases. A defined oxygen minimum zone at the mouth of the Gulf of California was predicted, however low oxygen concentrations were found throughout the measured profile. This study analyzed chemical characteristics in areas that have not had much previous study.

b) c)

d) e)

Figure 16: Comparison of water characteristics in the Southern California Bight (green and purple) and the Gulf of California (red and blue). a) Locations of stations S189-004, S189-020, S189-048 and S189-059. b) Salinity profiles. c) Oxygen profiles. d) Phosphate profiles. e) Temperature profiles.

29 The Oxygen Minimum Zone and its Effect on the Habitation Depths of Zooplankton in the Eastern Tropical Pacific Laura Nelson and Kyle Detwiler

Abstract The oxygen minimum zone (OMZ), an area of the water column with little dissolved oxygen, is a prevalent feature in the eastern tropical Pacific. Studying the relationship between the OMZ and zooplankton concentrations, we hypothesized that zooplankton, which require oxygen for respiration, would be found in greatest concentrations at depths outside the OMZ. Dissolved oxygen data obtained from Nisken bottle sampling identified the upper interface of the OMZ near the Southern California Bight (SCB) between 500 m and 600 m depth, and found that oxygen concentrations increased below 750 m depth. The OMZ in the Gulf of California was shallower, near 200 m-300 m depth. The dissolved oxygen minima levels at the stations sampled typically ranged from 0.50 ml/l to 0.70 ml/l. Echo intensity data obtained from the Acoustic Doppler Current Profiler (ADCP) indicated the largest zooplankton concentrations were mostly found at or above the upper interface of the OMZ. Zooplankton concentrations in the Gulf of California were also shallower than those offshore and in the SCB. It is possible that the shallower OMZ in the Gulf contributes to the shallower zooplankton concentrations. These results may demonstrate technological limitations for the ADCP in waters with a shallow OMZ (hence shallower zooplankton concentrations) since the ADCP relies on echoes reflected off zooplankton to calculate currents. Nevertheless, the data show a possible relationship between dissolved oxygen and zooplankton concentrations.

a) b) ADCP Echo Intensity (counts) Dissolved O2 (mL/L) 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0 20 40 60 80 100 120 140 160 180 200 0 0

100 100

200 200

300 300

) S189-020 (12 nm NW of Santa Catalina ) m Island) m 400 S189-002 (SE of Santa Catalina Island) 400 h ( pth ( pt S189-030 (8.5 nm NW of Isla de e e D

D Guadelupe) S189-020 (San Nicholas Basin) S189-048 (20nm NE of Punta Arena) 500 500 S189-026 (72 nm SSW of Cortez Bank) S189-052 (Isla Cerralvo)

600 S189-048 (20nm NE of Punta Arena) 600 S189-061 (4 nm E of Isla Carmen)

S189-049 (4nm SE of Isla Cerralvo) ADCP Quality Threshold 700 700 S189-052 (Isla Cerralvo)

800 800

Figure 17: Profiles of a) dissolved oxygen and b) ADCP echo intensity from stations within the Southern California Bight (S189-002, S189-020), offshore of the continental shelf (S189-026, S189-030), and within the Gulf of California (S189-048, S189-049, S189-052, S189-061; gray lines). ADCP echo intensity below 30 counts (indicative of low concentrations of zooplankton or other acoustical reflectors) is considered insufficient for accurate determination of currents.

30 An Examination of the Currents of the Southern California Bight during October 2003 Sara Nelson and Mark Kuske

Abstract We observed the currents present in the California Current System (CCS) within the Southern California Bight (SCB) during October 2003. This area is important because it is the intersection of the four major currents of the CCS, the California Current, the Countercurrent, the Undercurrent and the Davidson Current. We examined the characteristics and locations of these currents within the SCB using an ADCP, a thermosalinigraph, and sea surface temperatures from Coast Watch satellite imagery. The Countercurrent was observed directly off the coast of San Diego flowing northward with a mean temperature of 20.22ºC and a mean salinity of 33.32 psu. The Undercurrent followed the same path as the Countercurrent with very similar characteristics but at a depth of 200-600 m, and with a slightly slower speed of 0.05-0.10 m/s. Influence of the California Current was apparent from cooler surface temperatures and a drop in salinity, but its location could not be determined because the S-189 cruise track did not pass directly over it.

Figure 18: Near-surface currents in the Southern California Bight indicated by vectors. The northward flow along the coast is indicative of the Countercurrent.

Figure 19: North-south component of currents from 0-800 m depth along the S-189 cruise track. The Countercurrent is evident as northward flow (warm colors) from 0-200 m, while the Undercurrent flows northward from 200-400 m depth. b)

31 The Influence of the Island Mass Effect on the Vertical Distribution of Phytoplankton in the Eastern Pacific Ocean William Palmieri and Matthew Fromboluti

Abstract When a current strikes an island, eddies tend to form on the opposite side. This is known as the island mass effect. Along the S-189 cruise track we observed properties near islands in the Southern California Bight, the Sea of Cortez and west of the Baja peninsula. One-meter resolution in vivo fluorescence data were used to find the depth of the deep chlorophyll maximum (DCM), which indicates the vertical distribution of phytoplankton in the water column. In general our results supported the hypothesis that islands change the distribution and production of phytoplankton in the water column by altering the current striking the island, causing DCMs to be shallower and higher in intensity. Often the change in DCM depth from upstream to downstream was less than five meters in depth. We also observed secondary chlorophyll-a features, separate from the DCM, downstream of islands such as Guadalupe Island.

a) b) Fluorescence (ug/l) Fluorescence (ug/l) 0 0.2 0.4 0.6 0.8 0 0.1 0.2 0.3 0.4 0 0 Catalina Island Guadalupe Island

Upstream, S189-030 20 20 Downstream, S189-032

40 40 ) )

m b m ( h h ( pt pt e De D 60 60

80 80 Upstream, S189-002 Downstream, S189-004

100 100

Figure 20: Profiles of in vivo fluorescence measured upstream (thin blue) and downstream (thick red) of a) Catalina Island and b) Guadalupe Island. Differences in the structure of the fluorescence profile and in the depth and magnitude of the deep chlorophyll maxima were observed.

32 Zooplankton Biomass Density and Diversity Observed from San Diego, CA to Puerto Vallarta, Mexico Celeste Plautz

Abstract The relationship between zooplankton biomass density and zooplankton diversity was examined. It was expected that if areas of high zooplankton biomass density were found, then areas of low zooplankton diversity would occur. Zooplankton samples were obtained by neuston net deployments daily at noon and midnight. Zooplankton biomass density increased in two ways. The first increase was found during night tows (mean= 0.045 ml/m2) compared to day tows (mean=0.014 ml/m2). The second zooplankton biomass density increase was observed upon entering the Gulf of California (GC) (mean of day tows increased from 0.009 ml/m2 to 0.025 ml/m2). Zooplankton diversity was not statistically different in day and night tows (mean=0.54 and 0.20, respectively), or when comparing diversity in the open ocean and the Gulf of California. No relationship between zooplankton biomass density and zooplankton diversity was found.

0.9

0.8

0.7 x e

d 0.6 n I y

t 0.5 si

ver 0.4 i D 0.3

0.2

0.1

0 0 0.02 0.04 0.06 0.08 0.1 0.12 Zooplankton Density (ml/m2)

Figure 21: Zooplankton diversity (Shannon-Wiener diversity index) versus zooplankton density from all stations except S189-064. The regression (red line) with correlation coefficient R2 = 0.0 indicates no statistically significant relationship between zooplankton biomass and diversity.

Day Density Night Density Day Night (ml/m2) (ml/m2) Diversity Diversity Mean Gulf of California 0.025 0.085 0.46 0.61 Open Ocean 0.009 0.020 0.57 0.56 All stations 0.014 0.045 0.54 0.20 Standard Deviation Gulf of California 0.015 0.097 0.21 0.09 Open Ocean 0.009 0.016 0.22 0.17 All Stations 0.014 0.067 0.22 0.16

Table 7: Mean and standard deviation of zooplankton biomass and diversity index for regions along the S-189 cruise track, computed for both day and night samples.

33 The Effects of Island Masses on Current Flow in the Eastern Pacific Patrick Schmidt

Abstract This study examined the interactions between current and island masses along the Baja peninsula in the eastern Pacific, and specifically the formation of eddies in the lee of the islands observed. Current direction and magnitude were recorded using the onboard Acoustic Doppler Current Profiler (ADCP). Observations were made both upstream, downstream, and in the lee of selected islands to determine the direction of prevailing currents. The Mexican islands along the cruise track that were observed were: Isla Guadalupe, Isla Cedros, Isla Cerralvo, and Isla Espiritu Santo. Island characteristics such as orientation to the current, shape, and size were analyzed to determine if a relationship could be found between island orientation and eddy formation. Patterns of laminar flow were found in cases where island orientation was longitudinal to current flow. Similarly, to a small extent eddies were found in the lee of islands with a perpendicular orientation. However, the data in this respect were mainly inconclusive.

Figure 22: Near-surface currents (22.7-42.7 m depth) in the vicinity of Isla Guadalupe as measured by the ADCP. Letters refer to data in Table 8.

Table 8: Analysis of regions in Figure 22, identified by letter, and selected because of apparent change in near-surface currents in the vicinity of Isla Guadalupe.

Label Avg. Direction Avg. Magnitude Position Remarks (degrees true) (m/s) A 097 0.148 29.68°N x 118.55°W Prevailing current north of the island. B Variable 0.060 29.50°N x 118.45°W Current weakens and direction becomes variable. C 200 0.266 29.46°N x 118.44°W Current strengthens and changes direction at the northern end of the island. D 263 0.093 29.05°N x 118.13°W Current weakens and becomes slightly variable in the lee of the island. E 343 0.266 29.28°N x 118.29°W Current intensifies at the southern end of the island and flows in a westerly direction. F 224 0.055 28.71°N x 117.90°W Current is still turbulent, beginning to clock around to its prevailing direction. G 006 0.335 28.56°N x 117.15°W Current intensifies and stabilizes in a new prevailing direction of north northeast.

34 A Distribution Study of Halobates along the Baja Peninsula and in the Gulf of California Emily Warrener

Abstract Distribution of the pelagic insect Halobates was studied along Baja California and in the Gulf of California. I hypothesized that three species, H.micans, H.sericeus, and H.sobrinus would be found in distinct areas separate from one another, and that sea surface temperature and salinity would correspond with distribution boundaries. In addition, I expected that nymphs and adults would be collected separate from one another, but that adult males and females would be distributed evenly. Halobates were collected in neuston net tows and sorted according to age, sex, and species, and sea surface temperatures and salinity were measured using a flow-through thermosalinograph. H.sericeus were only collected in one location, and distribution of H.micans and H.sobrinus was consistent with previous studies. Evidence was found of sea surface temperature and salinity corresponding with distribution boundaries. Many more nymphs were collected than adults, and both were collected at most stations. Adult males and females were distributed evenly throughout the samples taken.

a) b) 32 31 30 29 28

) 27 N g 26 e d ( 25 ude t

i 24 t

La 23 22 H. Sericeus 21 H. Micans 20 H. Sobrinus 19 None 18 -120 -118 -116 -114 -112 -110 -108 -106 Longitude (deg E)

Figure 23: a) Map indicating neuston net tows along S-189 cruise track. Symbols indicate species of Halobates collected at each station, if any. b) Sea surface temperature measured hourly with the flow-through thermosalinograph along S-189 cruise track. All H. micans and H. sobrinus were collected south of the heavy black line.

35 Distribución de Peces Juveniles Epipelagicos Andrea Levy de la Torre

Introducción Los peces son uno de los grupos más grandes de vertebrados. En las aguas del Golfo de California existen formas y tamaños muy distintos, su conteo y separación por familia facilita su estudio. En México el estudio de los peces incluye diferentes aspectos, como son; biodiversidad, importancia comercial para consumo humano y de ornato. Para la realización de cualquier estudio relacionado con peces marinos, es necesario saber qué especies y qué cantidad existen, además de conocer la distribución de estas. Actualmente existen varios estudios relacionados con la distribución de los peces adultos, aunado con estudios de taxonomia. Son pocos los trabajos realizados sobre la distribución de sus etapas juveniles y de sus larvas en latitudes menores a 23°N frente a las costas mexicanas del Pacífico, en el presente trabajo se describen las familias de los peces juveniles epipelágicos de La Paz hasta Puerto Vallarta.

30 )

N 28 deg ( 062 26

ude 063 t i

t 065 a L 24 066 068 22 070 072 071

20 073 077 079 076 078 074 1 075 18 -123 -120 -117 -114 -111 -108 -105 Longitude (deg E)

Figura 24: Area de estudio y localización de las estaciones de muestreo.

Atherinidae Hemirhamphidae Diodontidae Exocoetidae

Coryphaenidae y l i Balistidae m

Istiophoridae Fa

Scombridae

others

Carangidae

Tetraodontidae

0 1020304050 Total Abundance (%)

Figura 25: Composición de las familias de peces presentes durante el crucero S-189.