. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 56 MARTIN W. JOHNSON AND ROBERT J. MENZIES. FIGURE 1. Limnoria tripunctata. Seasonal attack on test blocks exposed for successive 30-day intervals at Stations A and B, San Diego Bay from August, 1952 to March 14, 1955. Seasonal temperature included. The intensity of settlement or attack on the blocks for a given period is taken to represent the intensity of migration for the period. It is determined by counting the number of burrows in the surface of the wood. Usually there are two animals, male and female, in each of the de
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 56 MARTIN W. JOHNSON AND ROBERT J. MENZIES. FIGURE 1. Limnoria tripunctata. Seasonal attack on test blocks exposed for successive 30-day intervals at Stations A and B, San Diego Bay from August, 1952 to March 14, 1955. Seasonal temperature included. The intensity of settlement or attack on the blocks for a given period is taken to represent the intensity of migration for the period. It is determined by counting the number of burrows in the surface of the wood. Usually there are two animals, male and female, in each of the deeper burrows. Surface temperature of the water was taken once each month at each station except for the period 15 August 1953 to 7 May 1954 when a continuous tempera- ture recorder was in operation near Station A. Salinities in San Diego Bay fluc- tuate but little. The mean annual value is about Requirements for a study of this nature are: (1) nearby ample source of gribble infestation; (2) little or no interference resulting from repair or removal of piling; (3) safety from ship action, heavy seas or pilferage; (4) absence of adverse con- ditions due to low dissolved oxygen or low salinity. These requirements were well met but for the already mentioned changes due to pier repair. RESULTS Seasonal Migrations An examination of the severity of attack on the test blocks reveals that migration occurs to a greater or lesser degree throughout the year, but as in L. Hgnorum, there was each year a period of pronounced increase in migratory activity. In migrating the animals swim freely and a special preliminary study designed to reveal diurnal behavior in nature indicates that the greatest swimming activity takes place at night. In Figure 1 is shown graphically the monthly seasonal fluctuations in migration between Aug. 12, 1952 and March 14, 1955 inclusive. The data used in compiling the figure were derived from the blocks submerged for successive 30-day periods with omissions
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
