rhizomes (see Figure 1). Observations made in 

 1966-67 (Food and Agriculture Organization, 

 1968) also suggest that green turtles in the 

 vicinity of Khor Umaira eat chiefly the leaves 

 of sea grasses. The local name for all sea grasses 

 is Zawee. 



No turtles were observed grazing in the 

 census plots at the time of collection, but sub- 

 stantial amounts of leaves had washed up on the 

 shores of the bay. 



The grasses were collected in the middle of 

 what was considered good turtle pasturage on 

 28, 29, and 30 July 1972. This was during the 

 peak of the Southwest Monsoon which in this 

 area generally prevails from April through Sep- 

 tember. The collecting sites were approximately 

 500 to 600 m from the nearest shore. Thirty 

 samples were taken in a homogeneous pasture 

 of Cymodocea sey^rulata and 30 samples from a 

 stand of C. serrulata and Syniigodium isoetl- 

 folium adjudged to be equally mixed. The sample 

 quadrats were 1/16 m^. The 60 samples were 

 taken at depths from 0.8 to 2.5 m with 70% of the 

 samples from depths of 1.8 to 2.5 m. The sam- 

 pling was done at or near low tide. Visibility, as 

 measured with a white Secchi disc 20 cm in 

 diameter, extended to the bottom. Pure stands 

 of Syringodium were not seen in the bay but a 

 more detailed census might reveal the presence 

 of such stands. 



The grasses were harvested at the ground sur- 

 face and weighed. No attempt was made to 

 separate epiphytic algae from the leaves. Wet 

 weight was obtained after removing the external 

 water by gentle blotting and dry weight was 

 determined by drying to constant weight in an 

 oven at 80°C. Cover was calculated by looking 

 straight down on a 1/16 m- quadrat and estimat- 

 ing percent coverage to the nearest 10% . Caloric 

 values were determined using a Parr semimicro 

 bomb calorimeter^ following the procedures of 

 Lieth (1968). However, since some of the tech- 

 niques with oxygen bomb combustion underesti- 

 mate ash content (Paine, 1971; Reiners and 

 Reiners, 1972) in a second series of combustions 

 aliquots of the material were ashed at 500° C for 

 5 h in a muffle furnace for determination of ash 



FISHERY BULLETIN: VOL. 71, NO. 4 



I 



■■' Reference to trade names does not imply endorsement 

 by the National Marine Fisheries Service, NOAA. 



Figure 1. — The stomach contents of an adult, female green 

 turtle caught on 22 July 1972 on the feeding pasture near 

 Ras al Ara. The stomach was packed solidly with sea 

 grasses. 



content. All caloric determinations are means of 

 three samples and each sample differed by less 

 than 3% . Plant nomenclature and terminology 

 follows den Hartog (1970). Regression proce- 

 dures follow those given in Steel and Torrie 

 (1960). 



RESULTS AND DISCUSSION 



The dry weights of C. aerrulata along with 

 corresponding cover data are given in Figure 2. 

 All of the leaf blades on the sample plots were 

 less than 20 cm long, with shorter blades asso- 

 ciated with shallow water. An average of 84.5% 

 (range 79-90% ) of the wet weight was water. As 

 Figure 2 shows, one would expect to find a dry 

 weight of 290 gim- in a pasture of Cymodocea 

 with 100% cover at Khor Umaira in July. The 

 corresponding wet weight would register about 

 1,871 g/m2. Gessner (1971) found that leaves of 

 turtle grass, Thalassia testudinum, in a dense 

 meadow off Venezuela registered 608 g/m- dry 

 weight and 2,504 g/m- wet weight. The mean 

 length of the leaves was 23 cm and the water 

 depth was 60 cm. In two sample plots of T. tes- 

 tudinum off the Florida coast, Phillips (1960) 

 recorded dry weight values of about 325 and 98 

 g/m-. The lower biomass was associated with 

 shallower water. 



1094 



