DRAFT SURVEY DESIGN FOR A COAST-WIDE CALIFORNIA CURRENT MONITORING SYSTEM revision: February 27, 2002
During the January 28, 2002 meeting of ACCEO, some group members expressed an interest in developing a short proposal or white paper for a coast-wide monitoring system. This document could be used to encourage participation and acquaint foundations, agencies and legislative groups with the concept.
An important first step was to identify the scope, design and cost of a coast-wide monitoring of the California Current. Two participants (Bograd & Boehlert) attending the MBML Meeting volunteered to draft a California Current pelagic monitoring plan that would be compatible with CalCOFI & IMECOCAL in order to maximize the benefits from existing lines and time series. The plan was for only the U.S. and Mexican coasts because Canadian participation in ACCEO planning has not begun. The key features of the Bograd/Boehlert plan are summarized below and in the survey map. Approximate costs for the survey are given in an excel spreadsheet. Comments on their draft plan by some La Jolla scientists (Hunter, Smith, Moser, Lynn, and Charter) are also included.
DESIGN:
- Continue current CalCOFI and IMECOCAL surveys and add 10 additional lines in the U.S. (Canadian enhancements not identified at this point).
- The ten new lines shall consist of pairs of lines near 5 different marine laboratories: Monterey, Bodega, Arcata, Newport, and Columbia River (see survey map).
- New lines shall extend 300 km (162 nm) offshore, 10 stations per line, at 30 km intervals between stations and 100 km between lines.
- New lines to be occupied quarterly and preferably, synoptically.
- New lines to utilize the most basic CalCOFI protocol: CTD casts to 500 m, rosette samples for nutrients and oxygen; bongo plankton tows (using 2 different nets) and possibly ADCP (depending on vessel).
- Average operation costs per locality for the 2 lines (occupied quarterly) was $182,000, plus the cost of 24 sea days ($240,000) bringing the total to $422,160 per locality per year. If the five laboratory-based localities were used, the annual cost for the 10 lines would be about 2 million dollars. As shiptime in the draft budget is more than 50% of the operation cost, shiptime is a major factor in implementation.
COMMENTS ON DESIGN:
- The reviewers felt this draft is a good first start, basic, and yet ambitious. Most enhancements will increase costs, but some trade-offs exist and are open to discussion, e.g., frequency of surveys, mesh sizes, extent of water chemistry measurements, number and length of lines, monitoring of zooplankton optically, acoustically, or using both methods, and other matters.
- The reviewers recommend adding manta (neuston) net tows to the station plan to increase take of neustonic fish larvae including sablefish, greenlings, lingcod, and cabezon, as well as larger specimens than taken in bongos. Because the manta net catches older, larger, and rarer larvae, it covers the quarterly cruise interval better than bongo tows. Sorting only one bongo mesh size (e.g., 500 um) to offset sorting costs for manta net samples is a possible trade-off.
- Participants may want to consider how design would best take advantage of historically occupied stations on the northwest coast of the U.S. including: CalCOFI 1972; Richardson et al 1969-1976 and TINRO-AFSC 1980-1987 (See M. Doyle 1992).
- The reviewers noted some existing lines (Newport and SECRET, and La Perouse) do not extend as far offshore as the proposed new lines, nor are all the standard CalCOFI measurements presently included on these existing lines.
