IVERSEN ET AL.: BIOLOGICAL DATA ON QUEEN CONCHS 



a group than queen conchs at Little Whale Cay and 

 Little Cockroach Cay (Table 4). Alcolado (1976) also 

 reported that queen conchs in Cuba grew slower in 

 areas of high density (5.2 conchs/10 m^) than in 

 areas of low density (0.08 conchs/10 m^). Appel- 

 doorn and Sanders (1984) reported similar results 

 in a laboratory experiment on small juvenile conchs. 



There was no significant interaction effect be- 

 tween size and location on growth of penned queen 

 conchs. Smallest conchs in cages grew fastest, 

 followed by intermediate-sized conchs (Table 5). 

 There were insufficient data for large penned conchs 

 to estimate their mean monthly growth. Among the 

 intermediate-sized conchs where density was 

 known, mean monthly growth was highest in pens 

 with the lowest density (0.1/10 m- compared with 

 0.2/10 m-). 



Randall's (1964) penned queen conchs (mean 

 length 6.2 and 7.5 cm, range 5.2-8.0 cm; N = 25) 

 grew slowly (0.26 cm/month), but these measure- 

 ments were made during winter months. Pen size 

 was not specified. In another experiment^ Randall 

 placed 16 tagged conchs (19.0-20.0 cm, X = 19.4 

 cm) in a "60 ft by 140 ft elliptical fenced area" dur- 

 ing winter and reported average growth of 0.1 cm/ 

 month through April when the experiment was 

 discontinued. 



Growth rates for our larger penned conchs (mean 

 length 10.3 cm) approximated Randall's rates (0.1 

 and 0.2 cm/month), even though our data were re- 

 corded throughout the year. Growth rates were 

 higher for our smaller conchs (mean length = 4.6 

 cm; mean growth = 0.4 and 0.2 cm/month) than for 

 larger conchs. 



modes of 634 queen conchs measured in October 

 1980 were present at 7.6, 12.5, and 17.0 cm, sug- 

 gesting length at ages 1, 2, and 3, respectively. 



Parameters in the von Bertalanffy (1938) equa- 

 tion were estimated by fitting a Walford (1946) line 

 to tagging data from Cat Cay, Vigilant Cay, Little 

 Whale Cay, and Little Cockroach Cay {N = 117). 

 Fitting a Walford growth line requires that the 

 growth rate decreases with age. Since the largest 

 queen conchs at Little Cockroach Cay grew faster 

 than the middle-sized juveniles, we excluded these 

 data from our calculations and obtained the fol- 

 lowing estimates of average length by ages (Table 

 6). 



Age 



Lt (cm) 



Our estimates of length at age from both length- 

 frequency analyses and von Bertalanffy estimates 

 of tagging data (excluding Little Cockroach Cay 

 data) indicate that queen conch in the Berry Islands 

 grow more slowly than those in the Virgin Islands 

 and some of the areas in Cuba where density was 

 low (0.8 conchs/10 m^). We suggest that the higher 

 densities of queen conch and cooler water temper- 

 atures in the Berry Islands may slow their growth 

 relative to other areas. 



Length at Age 



Estimates of length at ages 1-3 were obtained for 

 Berry Islands queen conchs by length-frequency 

 analysis (Cassie 1954) and by fitting the von Bertal- 

 anffy equation to tagging data. Distinct length 



Length-Weight Relationship 



Whole animal weight(minus the shell)-shell length 

 relationships were derived for queen conch sampled 

 at Chub Cay (N = 39), Frazer's Hog Cay (A^ = 32), 

 and Bird-Cat Cay Channel (A'' = 34). Log^o 



Table 5. — Comparison of mean monthly growth rates (cm) for penned queen conch. Underlined locations indicate no significant difference 

 in monthly growth between locations as determined by Student-Newman-Keuls test. 



Size class 



Tagging location 



9.6 cm 



Pen 7 



(0.04) ± '0.07 

 W = 25 



Pen 9 



(0.21) ± 0.06 

 A/ = 25 



Small Wood Cage 



(0.24) ± 0.06 

 A/ = 38 



Large Wood Cage 



(0.35) ± 0.06 

 A/ = 66 



9.7-15.3 cm 



Pen 5 



(-0.05) ± 0.04 

 A/ = 38 



Pen 6 



(-0.01) ± 0.01 

 A/ = 38 



Pen 7 



(0.04) ± 0.02 

 A/ = 64 



Pen 2 



(0.08) ± 0.02 

 A/ = 48 



Pen 9 



(0.11) ± 0.04 

 A/ = 56 



Pen 3 



(0.15) ± 0.03 

 A/ = 45 



Pen 1 



(0.17) ± 0.05 

 A/ = 34 



15.4 cm 



Insufficient data 



'95% confidence interval. 



305 



