Database for euphausiid species identification, life history phase, and size distribution from selected cruises from Southern Baja California to Central California. All samples collected with a 1-m diameter ring net or a 0.71-m diameter CalBOBL bongo net on CalCOFI cruises from 1951 to present. Analyses conducted by Ed Brinton and Annie Townsend, and database developed and maintained by the Ohman lab, SIO, together with the SIO Pelagic Invertebrates Collection.

Brinton and Townsend Euphausiid Database (BTEDB) website:


1. Cruises

The samples for this database originate from CalCOFI cruises for the period 1951-present. The cruises selected for analysis have changed over time, depending on the research question originally addressed. In some years only one cruise, the springtime cruise, was enumerated. For most years at least two cruises were enumerated, usually spring and winter. Between 1953-1959 and again in 1969, 1978 and 1984, all cruises were enumerated.

All samples are collected with a Cal1MOBL or CalBOBL Net (bongo net; Ohman and Smith 1995). For details on net sampling protocols at sea, see:

2. Regions

Five geographical regions are identified in this data set:

  • Central CA= CalCOFI lines 57 - 73
  • Southern CA = CalCOFI lines 77 - 93
  • Northern Baja CA= CalCOFI lines 97 - 110
  • Central Baja CA = CalCOFI lines 113 - 130
  • Southern Baja CA= CalCOFI lines 133-140

3. Sample selection

As with the cruise selection, the method for selecting samples depended on the research of interest at the time. Usually only nighttime samples were enumerated. If only nighttime samples were selected, night is defined as 1 h after sunset until 1 h before sunrise. Occasionally all samples were enumerated without regard to time.

4. Species selection

All euphausiid species have been identified from all the samples analyzed. Thirty-nine species have been identified from CalCOFI station lines 57 to 140.

5. Life history categories

All euphausiid data are enumerated by life history phase (calyptopis, furcilia, juvenile or adult) except for the periods, 1953-1959, 1969, 1978, 1984 and cruises 8303 and 9103, where counts were made by measuring each specimen's total length to the nearest mm (Brinton et. al. 1999/2000). In these years adult males and females were enumerated separately. On cruise 6601 the category "Larvae" (= calyptopis + furcilia) is used.

6. Sub-sampling protocol

Aliquots are made in one of two ways, with a Folsom plankton splitter or a method developed by Brinton (1962, 1962a). Aliquots for each sample vary in size. When an initial count is insufficient for a meaningful abundance estimate of one or more species, additional fractions are counted. Some samples are counted in their entirety when the number of individuals counted is too low.

7. Identification of species

All species' identifications are made by Edward Brinton (now deceased, 2010) or Annie Townsend; see Brinton, et al. 2000.

8. Data entry

All euphausiid species have been identified from all the samples analyzed. Thirty-nine species have been identified from CalCOFI station lines 57 to 140.

8. References

  • Brinton, E. 1962. The distribution of Pacific euphausiids. Bulletin of the Scripps Institution of Oceanography 8: 51-270.
  • Brinton, E. 1962a. Variable factors affecting the apparent range and estimated concentration of euphausiids in the North Pacific. Pacific Science 16: 394-408.
  • Brinton, E., M.D. Ohman, A.W. Townsend, M.D. Knight, and A.L. Bridgeman. 1999/2000. Euphausiids of the World Ocean, CD-ROM. MacIntosh version 1.0 ed. (1999), Windows version 1.0 ed. (2000). UNESCO Publishing and ETI (Expert Center for Taxonomic Identification, University of Amsterdam).
  • Ohman, M.D. and P.E. Smith. 1995. A comparison of zooplankton sampling methods in the CalCOFI time series. CalCOFI Report 36: 153-158.