CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...

REPORTS VOLUXE XI, 1 JULY 1963 TO 30 JUNE 1966 79FIGURE 6a. Gill-raker of the anchoveta Engraulis ringens, 50mm long.it is made up mainly by Copepoda. On the contrary,the aspect of the gill-rakers of the juveniles having alength of 90 mm shows great differences between thetwo species (Figures 5b and 6b). The gill-rakers ofthe juveniles of E. ringens are longer and with morenumerous and longer denticles. At this stage of theirdevelopment the individuals of this species have adiet based completely on phytoplankton.Another finding which deserves to be interpretedis the presence of an amount of detritus and veryfine sand grains in the intestinal content of some ofthe juveniles of the 41.0-90.0 mm length class. TheFIGURE 6b. Gill-raker of the anchoveta Engraulis ringens, 90mm long.intestinal content of these individuals contained alsoa great quantity of Triceratizinz, a diatom which isabundant in water layers which are close to thebottom. In the spring the skeletons of benthic Foraminiferawere found in the food of three individuals.The highest value, both for the frequency of occurrenceand for the percentage weight rate, ofdetritus in the intestinal content of the juveniles ofthe anchovy was found during the winter. During thesummer, on the contrary, no individual has beenfound containing benthic elements in its intestine.The aforementioned findings show that the juveniles