Figure 13 gives similar data for three other im- 

 portant crustacean components of the micronek- 

 ton, namely galatheids, portunids, and adult sto- 

 matopods (squillids). These forms were not taken 

 during cruise TO-60-2 and occurred at only 17 

 stations on cruise TO-58-1, generally only one 

 kind to a station (although both portunids and 

 stomatopods were collected at station 96, in a 4 : 1 

 ratio by volume, see table 5). Tlieir distribution is 

 much more localized than the distribution of the 

 other components previously discussed. 



Tlie galatheids were all adult Pleuroncodes 

 flanipes ("red crab'") ; a few small samples of 

 galatheid juveniles, which could not be identified 

 to species, are listed in tables 3 and 5 but are not 

 shown in figure 13. This family was by far the 

 largest in volume for the total micronekton of all 

 the cruises (tables 3 and 4), but it was taken only 

 in a small part, of the region covered, where it was 

 generally very abundant. The area of occurrence 

 shown in figure 13 (and in fig. 15, whicli gives data 

 for other cruises) is the west coast of Baja Cali- 

 fornia and offshore in the California Current Ex- 

 tension as far west as long. 120° "VV. and as far 

 south as lat. 18°30' N. (Clarion Island) ; table 5 

 gives the data on which figures 13 and 15 are based. 

 These western and southern limits are approxi- 

 mately the same as reported by Alverson (1963a) 

 and Longhurst (1967) ; according to these autliors, 

 P. planipes also occurs farther east (across the 

 Gulf of California) and farther north (to 

 Monterey in central California). It did not occur 

 in the material of Aron (1959, 1962a) or King and 

 Iversen (1962). Because of the generally high 

 standing crops of this animal encountered in 

 area 1, this area yielded 47.4 percent of all the total 

 micronekton collected in the 18 areas (table 3), al- 

 though only 21 hauls (16.0 percent of the total for 

 all areas) were made there (table 1) ; mean stand- 

 ardized volume of P. planipes for the hauls was 

 56.9 ml. per 1,000 m.^ (table 5). Area 1 includes 

 several localities where coastal upwelling occurs 

 seasonally, as noted earlier. 



The portunid material of figures 13 and 15 was 

 99.4 percent Portunus affinls (table 3). Portunids 

 were taken in the 1.5-m. net only along the coast 

 from southeastern Mexico to northern Colombia, 



to about 200 nautical miles (370 km.) offshore. 

 Alverson (1963a) charted a distribution of P. 

 affinis which has a greater range in latitude ( about 

 23° N. to 10° S.) and a wider range offshore (to 

 about 700 nautical miles — 1,300 km. — from the 

 continent). Aron (1959, 1962a) did not mention 

 portunids; King and Iversen (1962) recorded only 

 two individuals from the central Pacific, both from 

 tropical latitudes. 



The stomatopod adults (or near-adults — our 

 specimens were pelagic, whereas adults are gener- 

 ally regarded as benthic) were even more localized 

 than the galatheids and portunids. They were taken 

 only along the coast of southeastern Mexico, es- 

 pecially in the Gulf of Tehuantepec (figs. 13 and 

 15). Alverson (1963a) noted that they occurred in 

 tuna stomachs only in areas 4 and 5, which include 

 the Gulf of Tehuantepec. Their abundance in that 

 region may be associated in some way with the 

 fact that the Continental Shelf is wider in the east- 

 ern part of the Gulf of Tehuantepec and in the 

 western part of area 5 than it is along most parts 

 of tlie eastern side of the eastern tropical Pacific. 



Figures 14 to 16 give information for total fish, 

 crustacean, and cephalopod micronekton taken in 

 night hauls on four other cruises (TO-59-1, 

 TO-59-2, TO-60-1, and TO-61-1), which were 

 made only along the Pacific coasts of Mexico and 

 Guatemala ; to the extent that cruise TO-58-1 was 

 concerned witli that area, the information about it 

 (the same as in figs. 6 to 8) has been included to 

 facilitate comparison between seasons (see below). 

 Figure 2 identifies the stations (see also table 1). 



The main features of distribution by area which 

 these figures show have already been mentioned. 

 In figure 15, code letters indicate the kind of 

 crustaceans which accounted for half or more of 

 the volume of Crustacea at a particular station. 

 Included were penaeids at station 59 of cruise 

 TO-60-1, which contributed practically all the 

 material of tliis family for all the cruises, as well 

 as the groups listed above. Many of the stations had 

 a heterogeneous cinistacean fauna, of which no one 

 group made up half or more of the volume (table 

 5) ; the number of these stations increased toward 

 the tropics. 



96 



U.S. FISH AND WILDLIFE SERVICE 



