Carmona Suarez and Conde DisliibLition and abundance of Calllnectes spp and Arenaeus cribrahus 



15 



= 22 Meofi 



Slolion I 27 4 30 24-30 



Slolion 2 27 6 30 25-30 



Stotlon 3 29 2 42 25-34 



Slolion 4 275 33 24-30 



Range Surface temperature 



50 



45 



40 



35 



„ 30 



& 25 



20 



IS 



10 



5 







/I : 22 Mean s e Range 



Slolion I 3709 047 30-43 



Slolion 2 36 57 44 30-40 



Slol.on 3 19 52 2 40 0-40 



Slolion 4 36 39 41 32-40 



Salinity 



xf£t^7^HM?-« 



g> 6 - 



F M A M 



JJASONDJF 

 I I 



1993 



M J J 

 -1994 - 



a S N D 



Sampling months 



Figure 3 



Surface temperature, salinity, and dis.solved oxygen at the foreshore and estuarine 

 stations in Ensenada de La Vela (Falcon, Venezuela). 



at the marine stations was C. danae (Table 2). The highest 

 number of species, six, was recorded at the estuarine site, 

 where C. danae clearly dominated with a relative abun- 

 dance of 75. 29f, followed by C. bocourti ( 14.1%), C. exaspera- 

 tus (4.5%), C. sapidus (2.5%), C. maracaiboensis (2.0%) and 

 C. laruatus (1.5%). Arenaeus cribrarius was absent from 

 the estuarine site. Overall, the highest diversity (Shannon- 

 Weaver index) was registered at the estuarine station, fol- 

 lowed by station 2, station 1, and finally .station 4, the most 

 exposed tract. Hills diversity number 1 (Nl), which indi- 

 cates abundant species, was also highest at the estuarine 

 station 3, followed by stations 2, 1, and 4 (Table 2). In a 

 comparison of the two main biotopes (all three marine sta- 

 tions vs. the estuarine station ) for the most frequent species 



(A. cribrarius and C. danae ), their abundance was dependent 

 on salinity ( G=306; df=l, P<0.005 ). However, their abundance 

 was independent of wave exposure, when only the stations 

 in the marine biotope were considered (G=5.624; df=2, 0.05 

 >P>0.1). 



Offshore A total of 173 swimming crabs were caught 

 witli crab pots. Abundance was highest at the seaward- 

 most station, followed by the inshore and midshore sta- 

 tions (Table 3). The average number of individuals per 

 pot at each site followed a similar sequence (offshore: 

 5.9 individuals/pot; inshore; 1.75 ind/pot; midshore: 1.5 

 ind/pot). Differences in abundance between offshore and 

 inshore and between offshore and midshore stations were 



