Bioenergetics and phenology of reproduction of the introduced red swamp crayfish, Procambarus clarkii, in Donana National Park, Spain, and implications for species management

1. The red swamp crayfish, Procambarus clarkii (Girard), is a North America n species which was introduced into the Lower Guadalquiviri Spain, in 1974. Procambarus clarkii has become a key species since it has greatly altered the functioning and structure of the ecosystems it has invaded. 2. Since P. clarkii spawn spontaneously throughout the year, it is to be ex pected that their ecological impact on the ecosystem may vary depending of the timing of habitat flooding (e.g. temporary freshwater marsh, and tempor ary or permanent pond). The objective of the present study was to understan d the reproductive phenology and bioenergetics of P, clarkii in Donana Nati onal Park, Spain, freshwater ecosystems, and consequently, propose some man agement plans for their populations. 3. Five stages of ovarian development were detected. Final ovarian maturati on occurred a few days before spawning and spawning was synchronized among mature females of all populations. Egg numbers hatched in pleopods ranged f rom 450 to 550. Timing of juvenile release from pleopods varied greatly (10 -35 days). 4. Gravid females support most of their metabolic needs by catabolizing car bohydrates (overall mean of O:N = 30.39), and to a lesser extent, lipids. T he aerobic and excretory metabolisms of gravid females were lower than thos e of immature animals of similar weight. 5. Analysis suggested that several factors influence the spawning of crayfi sh at the monitored sites. The major factors are water regime and temperatu re. Red swamp crayfish appear to be a spontaneous spawning species which ma y adjust their reproductive cycle to the timing of flooding, enhancing the utilization of available resources. 6. Populations of P. clarkii in Donana National Park could be controlled by the management of the water regime and by devising a fishing scheme which would maintain an appropriate population structure.