in May. The great abundance of D. texasianus in May was the principal 

 factor. November samples had the least number of individuals. The 

 number of species gradually increased from a low of 7 in November to a 

 high of 22 in August (Table 19) . 



(3) Station 3 . Station 3 was located between the first and 

 second sandbars, and was represented by 85 species of macro inverte- 

 brates and 3 species of fish. This station was also sampled quarterly 

 on all nine transects and produced the highest number of individuals 

 per sample of the five stations on transects (Table 16). The number 

 of species was nearly triple the numbers from stations 1 and 2. Five 

 species were abundant at this station, and accounted for 81.5 percent 

 of the individuals. The pelecypod, D. texasianus, again was one of 

 the most abundant species with 28 percent of the individuals. The 

 species with the next highest number of individuals was another new 

 species of amphipod, Aeanthohaustorius n. sp. It represented 31 

 percent of the individuals. The two species ranked third and fourth 

 in abundance were also new species of amphipods. Collectively, the 

 three amphipods species accounted for almost 49 percent of the 

 individuals. The other two new species of amphipods were 

 Protohaustorius n. sp., and Pseudohaustorius n. sp. Ranked fifth in 

 abundance was a polychaete, Spio pettiboneae, representing 5 percent 

 of the individuals. The polychaete, S. squamata, which was abundant 

 at stations 1 and 2, occurred only in the February samples and 

 represented only 0.09 percent of the total catch or 0.8 percent of the 

 polychaetes (Table 20). Twenty- three of the 85 species of macroinver- 

 tebrates were represented by only one specimen at station 3. 



The number of species in the major animal groups varied from 25 

 species per taxon (Polychaeta) to 1 per taxon; 12 major taxa were 

 represented only by a single species (Table 20). Three of the 25 

 species of polychaetes (5. pettiboneae, Dispio unoinata, and Paraonis 

 fulgens) accounted for 85.6 percent of the polychaetes. Nine of the 

 13 species of amphipods were new species; collectively, these 9 species 

 accounted for 99.6 percent of the amphipods and 49.6 percent of the 

 total individuals at station 3. Since D. texasianus was clearly the 

 dominant bivalve, accounting for 94 percent of the pelecypods 

 (Table 20), the number of species of pelecypods increased substantially 

 to 10. 



Seasonally, the highest number of individuals occurred in May. The 

 two most abundant animals were D. texasianus and Aaanthohaustovius n. 

 sp. The month with the least number of individuals was February. The 

 month of August again had the highest number of species;' February had 

 the least at station 3 (Table 20) . 



(4) Station 4. Station 4 was located on the second sandbar, 



63 



