RESULTS 
Nature of Distributions 
Distributions of zooplankton, fish eggs, and fish larvae 
are patchy in the eastern Gulf (Figs. 2-4). Means, standard 
errors of the means, and coefficients of variation were cal- 
culated for each kind of observation for each cruise (Table 2). 
For the 12 cruises, mean zooplankton volumes ranged from 
69.1 to 287.8 cc/1,000 m* in the study area. The mean value 
for all cruises combined was 153.4 cc/1,000 m*. Mean 
numbers of fish eggs under 10 m? of sea surface ranged from 
163.1 to 927.1 for the 12 cruises, and the pooled mean for ~ 
combined cruises was 510.1. Fish larvae mean abundance | 
ranged from 55.3 to 825.4 under 10 m? of sea surface and the || 
pooled mean was 435.5. | 
The relatively high standard errors and high coeffi- 
cients of variation (Table 2) reflect patchiness in distribution }) 
of these organisms in the eastern Gulf. The coefficient of | 
variation is a relative measure of the variability in abun- 
dance or concentration. For plankton volumes, the coeffi- 
cient ranged from 56.3 to 187.2% on the 12 cruises, | 
averaging 91.8%. The range for fish egg abundance was 58.4 | 
to 174.1%, averaging 99.4%. For fish larvae abundance, the | 
Table 2.— Mean zooplankton volumes (cubic centimeters per 1,000 m‘), and numbers of fish eggs and larvae 
(numbers under 10 m’ sea surface) for eastern Gulf of Mexico cruises, 1972-74. 
Number of Standard Coefficient of 
Cruise Cruise date observations Mean error variation (%) 
Zooplankton volumes 
(ce per 1,000 m‘) 
8B 7201 & GE 7202 Feb. 1972 26 69.1 9.7 (ilar 
GE 7208 May 1972 28 107.1 16.7 82.4 
GE7210 June 1972 13 287.8 149.4 187.2 
IS 7205 Sept. 1972 34 181.0 21.0 67.8 
IS 7209 Nov. 1972 49 119.3 9.9 58.3 
IS 7303 Jan. 1973 50 152.9 13.3 61.4 
IS 7308 May 1973 49 204.3 25.0 85.8 
IS 7311 June-July 1973 51 120.2 11.9 70.9 
IS 7313 Aug. 1973 50 194.9 31.2 113.1 
IS 7320 Nov. 1973 51 131.3 10.4 56.3 
CL7405 Mar. 1974 36 92.2 122 79.3 
CL7412 May 1974 45 219.1 54.6 167.1 
Total 482 153.4 8.5 91.8 
Fish eggs 
(number under 10 m? sea surface) 
8B 7201 & GE 7202 Feb. 1972 30 517.6 164.5 174.1 
GE 7208 May 1972 30 577.7 119.9 113.7 
GE 7210 June 1972 13 527.2 85.4 58.4 
IS 7205 Sept. 1972 34 578.8 72.5 73.1 
IS 7209 Nov. 1972 50 186.5 21.9 83.0 
IS 7303 Jan. 1973 51 874.9 58.8 112.1 
IS 7308 May 1973 49 872.2 129.7 104.1 
IS 7311 June-July 1973 51 450.2 50.2 79.6 
IS 7313 Aug. 1973 50 725.1 158.5 154.6 
IS 7320 Nov. 1973 51 163.1 18.4 80.7 
CL 7405 Mar. 1974 32 291.1 42.6 82.7 
CL7412 May 1974 42 927.1 109.0 76.2 
Total 483 510.1 30.3 99.4 
Fish larvae 
(number under 10 m? sea surface) i 
8B 7201 & GE 7202 Feb. 1972 30 226.6 46.2 111.7 
GE 7208 May 1972 30 414.3 47.5 62.8 
GE 7210 June 1972 13 341.5 130.9 138.1 
IS 7205 Sept. 1972 34 825.4 112.1 79.2 
IS 7209 Nov. 1972 50 295.5 45.6 109.0 
IS 7303 Jan. 1973 51 301.2 45.1 106.9 
IS 7308 May 1973 49 613.5 62.5 71.3 
IS 7311 June-July 1973 51 551.5 77.8 100.8 
IS 7313 Aug. 1973 50 581.6 94.8 115.2 
IS 7320 Nov. 1973 51 346.0 55.5 114.5 
CL7405 Mar. 1974 32 55.3 12.6 129.3 
CL7412 May 1974 42 519.2 89.7 112.0 
Total 483 435.5 19.5 104.2 
12 
