PLANKTON STITDIE?«* 



PLANKTON STATIONS werc occupicd during the months of June through 

 October, off the western coast of South America, the earlier stations 

 carried out off Chile, gradually moving northwards to Ecuador in October. 

 Fifty bottles of plankton were taken and examined. The area studied 

 proved to be rich in plankton, as exemplified by the appended list of 

 stations, giving the volumes of each bottle. Upon reading the volumes 

 of the individual hauls, it was noted that the richest bottles were usually 

 obtained farther away from shore, during the hours of darkness. 



The main constituents of many of the bottles were euphausiids, cope- 

 pods, salps, chaetognaths, and stomatopod larvae. For example, LM 1, 

 mainly contained copepods; LM 4, copepods and chaetognaths; LM 5, 

 salps; LM 6, salps and euphausiids; LM 7, stomatopod larvae; LM 13, 

 euphausiids and stomatopod larvae; LM 14, copepods, euphausiids, chae- 

 tognaths, and stomatopod larvae; LM 15, copepods and diatoms; LM 17, 

 salps; LM 18, stomatopod larvae; LM 20 provided a very good cross 

 section of various phyla represented in the plankton, although the major 

 portion of the contents were salps, medusae, chaetognaths, and stomatopod 

 larvae; LM22 and 23, copepods; LM 25, copepods and medusae; LM 26, 

 27 and 28, copepods; LM 29, siphonophores, copepods, and euphausiids; 

 LM 30, copepods and medusae; LM 32, copepods; LM 35 and 36, chae- 

 tognaths, and copepods; LM 38, chaetognaths and diatoms; LM 39, salps 

 and siphonophores; LM 41, copepods, and colonial siphonophores; LM 43, 

 copepods and diatoms; and, LM 44, chaetognaths, copepods, and salps. 

 The richness of plankton samples collected in these waters should indicate 

 an excellent fishing area since many larval, juvenile, and adult fish feed 

 solely on plankton. 



The main purpose of the plankton hauls made by the Marron Expedi- 

 tion was to acquire billfish larvae of the families Istiophoridae (sailfish and 

 marlin) and Xiphiidae (swordfish) but none were found. The absence of 

 billfish larvae is probably seasonal. The expedition reported adults in the 

 collecting areas, none of which were in spawning condition. In general, 

 few larval fish were collected, but many different eggs were noted, covering 

 a wide range of groups. The major families of larval fish present were the 

 Synodidae (lizard fish), Clupeidae (herrings), Myctophidae (lantern 

 fish), and Nomeidae. Those stations having larval fish were LM 1 (1 fish), 

 LM 6 (1), LM 9 (1), LM 12 (20), LM 13 (10), LM 14 (5), LM 18 

 (13), LM 19 (5), LM 20 (6), LM 24 (4), LM 27 (2), LM 32 (2), 

 LM 33 (141 Synodontidae), LM 35 (5), LM 36 (3), LM 37 (1), 

 LM 39 (8), LM 40 (2), LM 42 (15), LM 44 (4), LM 45 (7), LM 46 



54 ' 



