526 



Abstract.— Growth and sexual matu- 

 ration were studied in the ghost shrimp 

 Lepidophthalmus sinuensts, a pest spe- 

 cies infesting oligohaline penaeid 

 shrimp culture ponds on the Caribbean 

 coast of Colombia. Sex ratio was signifi- 

 cantly female-biased over four years of 

 sampling. Development of ovaries, in- 

 dexed as relative width, peaked prior 

 to peak occurrence of ovigerous females 

 and either coincided with or immedi- 

 ■' ately followed the quarter of lowest 

 ambient salinity. Ovigerous females oc- 

 curred in all months, but the greatest 

 mean percentage occurred in the first 

 or second quarter of each year. Size and 

 coloration of ovaries varied by matura- 

 tional stage, and monthly counts of eggs 

 per female peaked in February-April. 

 Detection of recruits <8-10 mm cara- 

 pace length (CD was sporadic, and 

 tracking of growth in recruitment co- 

 horts was not possible. Mean CL of the 

 population increased slowly over the 

 first two years of sampling, as the per- 

 centage of males in the population in- 

 creased. Sexual maturity in both males 

 and females was evident in relative 

 growth changes of the major chela. 

 Analysis of growth in chela width, 

 scaled to carapace length, suggested 

 that males mature at about 11.0-11.3 

 mm CL, whereas females mature near 

 10.8-11.2 mm CL. Prematuration posi- 

 tive allometric growth did not differ be- 

 tween sexes, whereas postmaturation 

 negative allometric growth in females 

 differed significantly from strongly 

 positive allometric growth in postma- 

 turation males. Relative growth in wet 

 weight of postmaturation males signifi- 

 cantly exceeded that of postmaturation 

 females. Expected female weight accu- 

 mulations from episodic ovarian devel- 

 opment were perhaps offset by simulta- 

 neous negative postmaturation growth of 

 the female major chela. An understand- 

 ing of growth, maturation, and the re- 

 productive cycle of this shrimp species 

 will help develop management strate- 

 gies to control infestations by this 

 callianassid pest species. 



Growth and maturation of the ghost shrimp 

 Lepidophthalmus sinuensis Lemaitre and 

 Rodrigues, 1991 (Crustacea, Decapoda, 

 Callianassidae), a burrowing pest in 

 penaeid shrimp culture ponds* 



Sergio F. Nates 



Darryl L. Felder 



Department of Biology and Laboratory lor Crustacean Research, 



University of Soutfiwestern Louisiana 



Lafayette, Louisiana 70504-2451 



E-mail address (for D L Felder, contact author) dlf4517'fflusl edu 



Manuscript accepted 11 August 1998. 

 Fish, Bull. 97:526-541 11999). 



In northern South America, the 

 ghost shrimp Lepidophthalmus 

 sinuensis Lemaitre and Rodrigues 

 has been found restricted to oUgo- 

 haUne estuaries on the Caribbean 

 coast of Colombia (Lemaitre and 

 Rodrigues, 1991). From previous 

 study of a congeneric species, osmo- 

 regulatory capacity and toler- 

 ance of hypoxia in this genus 

 (Felder, 1978, 1979; Felder et al., 

 1986) appear to exceed abilities re- 

 ported in most other callianassid 

 genera (Thompson and Pritchard, 

 1969; Forbes, 1974, 1978; Mukai 

 and Koike, 1984; Posey, 1987 ), Such 

 adaptation has allowed members of 

 the genus to exploit extensively low 

 salinity habitats, especially richly 

 organic silty bars and banks of 

 lower river mouths or intertidal 

 mudflats (Felder and Manning, 

 1997), In L. sinuensis and some 

 eastern Pacific congeners (Nates 

 and Felder, 1998), this adaptation 

 also includes sediments of tropical, 

 estuarine ponds in which penaeid 

 shrimp are cultured. 



Dense accumulations of ghost 

 shrimp in these penaeid culture 

 ponds are favored by their abbrevi- 

 ated larval development (Nates et 

 al., 1997). At high levels of infesta- 

 tion by these burrowers, metabolic 

 impacts and bioturbation appear to 

 decrease penaeid shrimp production 

 by reducing survival rates of post- 



larvae and slowing growth to mar- 

 ketable size (Nates and Felder, 

 1998 ). A thorough understanding of 

 maturation and reproductive cycles 

 in L. sinuensis is essential to devis- 

 ing effective long-term control mea- 

 sures for such infestations, espe- 

 cially to limit or replace the pesti- 

 cide treatments that have been used 

 to date (Nates and Felder, 1998), 

 Thus far, timing and frequency of 

 pesticide applications in shrimp 

 mariculture have been devised by 

 trial and error effects on penaeid pro- 

 duction, without specific attempts to 

 target treatments to peaks in repro- 

 ductive activity of ghost shrimp or to 

 achieve control by modifications in 

 water management. 



Although some species of the 

 Callianassidae burrow to depths of 

 2 m or more (Pohl, 1946; Poore and 

 Suchanek, 1988; Manning and 

 Felder, 1991; Felder and Griffis, 

 1994), the difficulty of monitoring 

 many natural populations has been 

 overcome by collecting them with 

 yabby pumps (see Manning, 1975). 

 Several aspects of population biol- 

 ogy for varied genera are now well 

 documented (Pohl, 1946; Hailstone 

 and Stephenson, 1961; Phillips, 



* Contribution 57 from the University of 

 Southwestern Louisiana, Laboratory of 

 Crustacean Research, Lafayette, LA 

 70.504-2451. 



