STATE OF OREGON DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES 910 State Office Building Portland, Oregon 97201 OPEN-FILE REPORT 0-86-7 THE STATE OF SCIENTIFIC INFORMATION RELATING TO THE BIOLOGY AND ECOLOGY OF THE GORDA RIDGE STUDY AREA, NORTHEAST PACIFIC OCEAN: NEKTON By James T. ~arve~' and David L. stein1 Final Report for Contract No. 63-630-8501 Submitted to: Oregon Department of Geology and Mineral Industries and the Living Resources Subgroup, Gorda Ridge Task Force Released February 1986 'college of Oceanography, Oregon State University Corvallis, Oregon 97331 20regon State University, Mark 0. Hatfield Marine Science Center Newport, Oregon 97365 NOTICE This report is based on results of a research program directed by the joint federal-state Gorda Ridge Technical Task Force, managed by the Oregon Department of Geology and Mineral Industries, and funded by the Minerals Management Service, U.S. Department of the Interior, through Cooperative Agreement. opinions expressed are those of the authors and do not constitute endorsement by the sponsoring agencies or the Task Force. The Oregon Department of Geology and Mineral Industries is publishing this paper because the subject matter is consistent with the mission of the Department. To facilitate timely distribution of information, camera-ready copy submitted by the authors has not been edited by the staff of the Oregon Department of Geology and Mineral Industries. TABLE OF CONTENTS Page List of figures and tables ........................... iv Preface ........................................ v SHRIMPS Studies within the Gorda Ridge Lease Area .......... 1 Distribution and abundance ....................... 1 Reproduction ..................................... 8 Growth ........................................... 11 Migration ........................................ 14 Food Habits ...................................... 17 Commercial exploitation .......................... 17 Relevant Studies Outside the Gorda Ridge Lease Area Distribution and abundance ....................... 18 Reproduction ..................................... 18 Migration ........................................ 19 Food habits ...................................... 19 Commercial exploitation .......................... 19 Gaps in the Data ................................... 19 CEPHALOPODS Studies Within the Gorda Ridge Lease Area .......... 21 Distribution and abundance ....................... 21 Reproduction ..................................... 29 Growth ........................................... 31 Migration ....................................... 31 Food habits ...................................... 33 Commercial exploitation .......................... 33 Relevant Studies Outside the Gorda Ridge Lease Area Distribution and abundance ....................... 33 Reproduction ..................................... 35 Growth ........................................... 35 Migration ........................................ 35 Food habits ...................................... 36 Commercial exploitation .......................... 36 Gaps in the Data ................................... 37 FISHES Studies Within the Gorda Ridge Lease Area .......... 38 Distribution and abundance ....................... 38 Reproduction ..................................... 62 Growth ........................................... 66 Migration ........................................ 69 Food habits ...................................... 74 Commercial exploitation .......................... 77 Relevant Studies Within the Gorda Ridge Lease Area Distribution and abundance ....................... 78 Reproduction ..................................... 82 Growth ........................................... 83 Migration ........................................ 83 Food habits ...................................... 83 Gaps in the Data ................................... 84 MARINE MAMMALS Studies Within the Gorda Ridge Lease Area .......... 85 Distribution and abundance ....................... 85 Reproduction ..................................... 91 Growth ........................................... 91 Migration ........................................ 92 Food habits ...................................... 92 Commercial exploitation .......................... 92 Relevant Studies Within the Gorda Ridge Lease Area . 92 Distribution and abundance ....................... 93 Reproduction ..................................... 100 Growth ........................................... 106 Migration ........................................ 108 Food habits ...................................... 111 Commercial exploitation .......................... 115 Gaps in the Data ................................... 116 SUMMARY AND CONCLUSIONS .............................. 118 Distribution and abundance ....................... 118 Reproduction ..................................... 119 Growth ........................................ 119 Migration ........................................ 119 Food Habits ...................................... 119 Commercial exploitation .......................... 120 ACKNOWLEDGEMENTS ..................................... 121 LITERATURE CITED ..................................... 122 iii LIST OF FIGURES Page Figure 1. Gorda Ridge Lease Area shown inside dashed line. ........................................ 2 LIST OF TABLES Table 1. List of shrimp species known to occur in the Gorda Ridge Lease Area either from collections or known distributions which overlap the lease area ... 3 Table 2. List of cephalopod species which are known to exist in the GRLA, or are presumed to inhabit the area because their distributions overlap the region. 22 Table 3. List of species and common names of fishes which are or expected to occur in the GRLA ......... 39 Table 4. List of marine mammal species with distributions which are known to overlap with the GRLA ............................................... 86 Preface The Gorda Ridge, a region of the northeastern Pacific seafloor located about 370 kilometers east of southern Oregon and northern California, is being explored and carefully mapped. One aim of the prospecting effort currently underway is the discovery of recent or past deep-sea hydrothermal vents and the attendant accumulations of metal- rich sulfide ores. Polymetallic sulfide deposits of significant size may be discovered, and these may eventually be commercially exploited. The Gorda Ridge Task Force and --ad hoc group is concerned with, among other things, evaluating the environmental and economic consequences of offshore mining activities. This group identified the assessment of scientific information relevant to biological processes in the region of the Gorda Ridge as a high-priori ty research area. To that end, in February 1985, the state of Oregon's Department of Geology and Mineral Industries contracted with Oregon State University (DOGMA1 Contract #63- 630-8501 ) for the production of this report. In brief this report presents the results of a thorough search of the scientific literature aimed at identifying and assembling the results of biological and ecological studies carried out in, or clearly relevant to the region of the Gorda Ridge Study Area (bounded by 40' to 46' N latitude and 130' W longitude to the continental shelf break). This region of seafloor included the Gorda Ridge, President Jackson Seamount Chain, and basins of Blanco Fracture Zone. The search of the scientific literature leading to this report was conducted using computer-assisted data retrieval systems, personal contacts with active researchers, and standard bibliographic references. The series of reports is divided into four parts: I. Plankton, 11. Benthos, 111. Seabirds, and IV. Nekton. This volume contains a review of the literature concerned with the nekton of the Gorda Ridge Lease Area. It has been divided into four sections dealing with I. Shrimps, 11. Cephalopods, 111. Fishes, and IV. Marine mammals. Within each section, biological processes (abundance and distribution, reproduction, growth, migration, food habits, and commercial exploitation) are summarized for each species for which there is information. This format is somewhat repetitive, but allows the reader the ability to find specific information on a species of interest without reading the whole document. I. SHRIMPS A. Studies Within the Gorda Ridge Lease Area The majority of studies dealing with pelagic shrimps in the Gorda Ridge Lease Area (GRLA) (Fig.1) have been done by W.G. Pearcy, C.A. Forss, R.A. Wasmer, and E.E. Krygier at Oregon State University (OSU). Collections of shrimps from midwater and bottom trawls have been used to describe the distribution and ecology of these nektonic animals. The majority were made off central Oregon between 70 and 130 km offshore between 1961 and 1976. Only for a few of the more abundant species are there data on abundance, reproduction, growth, migrations, or feeding habits. The following discussion will outline current knowledge regarding shrimp within the GRLA. Species omitted from discussion of individual processes indicates lack of data concerning that species. Pandalus jordani is included below, but it occurs usually only on the shelf. A few processes for which we have data on this species occur in the GRLA, and these are included below. Other information is relevant only to collections made on the shelf and has not been included. 1. Distribution and abundance Family Penaeidae Bentheogennema borealis Only 14 specimens were captured in 335 midwater trawls 120