The Fecundity, Time of Egg Development and Juvenile Production in Spiny-Cheek Crayfish (Orconectes Limosus) Under Controlled Conditions

Abstract

We comprehensively describe the fecundity and time of embryonic development of the spiny-cheek crayfish (Orconectes limosus). Linear relationships between female size and ovarian fecundity, pleopodal fecundity, and production of juveniles at the 3 rd stage, were confirmed. The ovarian fecundity was evaluated for the smallest as well as largest females in the sampled population (43-93 mm of body length); the number of oocytes (eggs) ranged widely, between 46 and 505. No significant difference was found between the ovarian and pleopodal fecundity observed just after egg laying. The value of the female gonadosomatic index just before laying was 4.2 ± 1.8% (0.8-7.7%). The mean diameter of eggs on female pleopods was 1.8 ± 0.2 mm (1.45-2.15 mm). A statistically significant difference was found between the numbers of eggs carried on individual pairs of pleopods. Mean time from laying to hatching was 46 ± 3.8 days (37-56 days), i.e. 647 ± 39.9 CTU (Celsius Temperature Units = degrees Celsius × days). Mean production of juveniles at the 3 rd stage was found to be 135.7 ± 67.24 (15-243) juveniles. The early sexual maturation and also high number of juveniles at the 3 rd stage per female gives this species a good predisposition for quick establishment in new localities. Key-words:Crayfish, Orconectes limosus, lifecycle, Czech Republic, juveniles, egg development. LA FÉCONDITÉ, LA DURÉE DU DÉVELOPPEMENT EMBRYONNAIRE ET LA PRODUCTION DE JUVÉNILES CHEZ L´ÉCREVISSE AMÉRICAINE (ORCONECTES LIMOSUS) DANS UN ENVIRONNEMENT CONTRÔLÉ RÉSUMÉCette étude décrit en détail la fécondité et la durée de développement embryonnaire de l´écrevisse américaine (Orconectes limosus) et confirme le rapport direct entre la taille de la femelle, la fécondité ovarienne, pléopodale et la production de juvéniles au stade 3. La fécondité ovarienne a été évaluée pour les femelles les plus petites aussi bien que pour les plus grandes femelles de la population échantillonnée (longueur corporelle de 43 à 93 mm). Bull. Fr. Pêche Piscic. (2006) 380-381 : 1171-1182 -1172 -significative entre la fécondité ovarienne et la fécondité pléopodale, observées juste après la ponte. La valeur de l´indice gonadosomatique (I.G.S.) trouvée juste avant la ponte est de 4,2 ± 1,8 % (0,8-7,7 %) pour les femelles et de 0,3 ± 0,05 % (0,2-0,4 %) pour les mâles. Le diamètre moyen des oeufs sur les pléopodes des femelles était de 1,8 ± 0,2 mm (1,45-2,15 mm). Le nombre d'oeufs sur les paires individuelles de pléopodes était très variable (95 à 492). La durée moyenne entre la ponte et l'éclosion était de 46 ± 3,8 jours (37 à 56 jours), i.e. 647 ± 39,9° Celsius × jour (543 à 730). La production moyenne de juvéniles au stade 3 fut de 135,7 ± 67,24 (15 à 243) juvéniles. La maturité sexuelle plus précoce et le grand nombre de juvéniles de stade 3 produits par femelles donnent à cette espèce une prédisposition à occuper plus rapidement de nouveaux sites.

Reproductive Plasticity in Freshwater Invader: From Long-Term Sperm Storage to Parthenogenesis

“…Females in all mated groups produced eggs and hatched and carried viable offspring. The number of 2 nd developmental stage juveniles per female was high in all groups (Table 2) and was comparable to the literature [7], [20], [23]. This suggests that omitted or truncated mating periods, long-term sperm storage, and absence of chemical stimulation by males at the start of a mating season did not reduce fecundity, and, conversely, the completion of both mating periods had no positive influence on reproductive output.…”

“…These features, common in the majority of Cambaridae, but specifically O. limosus consist of early maturation enabling a short generation cycle [22], [34], [35]; high fecundity even of small females maximizing numbers of offspring [23], [36], [37]; periodic occurrence of morphologically distinct sexually active (form I) and sexually inactive forms (form II) in males and females providing a mechanism to utilize resources effectively in the most important life stages [24], [25], [38], [39]; autumn and spring mating maximizing the probability of successful mating [22], [33], [37], [40]; the capability of sperm storage to circumvent extreme conditions [7], [41], [42]; and parthenogenesis as a tool for alternative reproduction if males are not available [17].…”

“…Autumn and spring mating seasons extend from 7 to 8 months (∼ from September to April). Females store sperm in a ventral body cavity, the annulus ventralis , until spawning in April/May [21], [22], [23]. The hypothetical basis for this strategy are numerous, with three key provisions: a) multiple paternity, to achieve as many mates as possible to increase the genetic diversity of progeny; b) mate selection, the search for a male with a preferred traits, and c) increasing chance of successful mating in a low population.…”

Studies of Annual Gonadal Development and Gonadal Ultrastructure in Spiny-Cheek Crayfish (Orconectes Limosus)

“…Several publications have focused on fecundity of this crayfish (STUCKI, 2000;HAMR, 2002;KOZÁK et al, 2006). In Québec populations, mating takes place in September-October and again in March-April (HAMR, 2002).…”

A review of ecological interactions between crayfish and fish, indigenous and introduced

“…Spiny-cheek crayfish were the earliest exotic crayfish introduced into Europe, and the first to bring in crayfish fungal plague, and are now widespread in lower quality habitats, chiefly deep rivers (Souty-Grosset et al, 2006). O. limosus is more active by day than are native astacids, and fecundity is also higher, with shorter development times (Kozák et al, 2006). Haertel-Borer et al (2005) studied the impact of O. limosus on European lake communities.…”