Roach (Rutilus rutilus) reproductive cycle: a study of biochemical and histological parameters in a low contaminated site

Abstract

Fish reproduction is subjected to worrying trends in many aquatic environments. In this study, we report the absence of histological and biochemical alterations in fish sampled in a low contaminated site (characterised by the absence of detectable oestrogenic activity and mutagenicity in sediment extracts). A total of 474 roach (Rutilus rutilus) were monthly sampled during 18 months, and no intersex fish were recorded after careful histological examination, thus indicating that the incidence of this phenomenon may be very low under natural conditions. Furthermore, mean male plasma vitellogenin concentration was 24 ng ml(-1) and was only slightly elevated during the spawning period (up to 120 ng ml(-1)) indicating that these low values may be characteristic of a low contaminated site. Of the male roach, 45.3% were sampled, a sex-ratio that did not significantly deviated from the expected 1:1 ratio between male and female. Results also showed that natural conditions can greatly affect the reproductive cycle of roach. Gametogenesis showed a biphasic pattern with first gonad maturation between September and December and a final maturation occurring at the end of winter/early spring. Under decreasing temperatures, particularly below 6 degrees C, gametogenesis was stopped or even regressed with secondary oocytes becoming rare under histological observation. Conversely, elevated temperatures during the winter lead to an earlier gonad maturation.

Evidence that elevated water temperature affects the reproductive physiology of the European bullhead Cottus gobio

“…In the same species, Gillet and Quetin (2006) also showed that an increase in water temperature of 1°C modified the life-history strategy of roach in Lake Geneva, by accelerating the development of gonads and affecting spawning date. Geraudie et al (2010) also reported earlier gonad maturation in female and male roach due to elevated temperature recorded during winter time.…”

“…The results of the present study, combined with previous data on reproductive and demographic traits of bullhead (Abdoli et al 2005(Abdoli et al , 2007Reyjol et al 2009), suggest possible deleterious effects of warming on its population dynamics. According to Geraudie et al (2010), reproduction is a key mechanism for the survival of a given species. The consequences on population and species survival could be severe unless development of phenotypic plasticity within a generation over multiple years or genetic adaptation over generations might produce individuals more tolerant to a warmer future.…”

“…Generally speaking, these modifying effects may lead to disorders of gametogenesis and gonad development, inhibition of ovulation, advance or delay in the timing of spawning and reduced embryonic survival in various species as for instance in the rainbow trout Oncorhynchus mykiss, the Atlantic salmon Salmo salar and the common wolffish Anarhichas lupus (King et al 2003;Pankhurst et al 1996;Pankhurst and Thomas 1998;Tveiten and Johnsen 1999;Tveiten et al 2001). Recently, Geraudie et al (2010) have reported that elevated temperature during winter time lead to an earlier gonad maturation of roach Rutilus rutilus. More generally, a review on the relative importance of external factors on the reproductive cycle in temperate fishes (including salmonids, percids and cyprinids) has shown that temperature is one of the main environmental cue driving the final stage of reproduction (Wang et al 2010).…”

Evidence for Hermaphroditism in the <i>Squalius alburnoides</i> Allopolyploid Fish Complex

“…Indeed, comparative studies on sex determination in distinct fish groups, revealed that the molecular mechanisms for sex determination can be temperaturedependent, even in species with a firm genotypic sex determination [reviewed in Ospina-Alvarez and Piferrer, 2008]. Another environmental factor associated with intersexuality in wild fish is the presence of endocrine-disrupting chemicals (EDCs) [Geraudie et al, 2009]. The relation between hermaphroditism and the anthropogenic impact on the rivers is now well established and was reported for several species of freshwater fish [Jobling and Tyler, 2003].…”

“…The fish were then classified as male, female or hermaphrodite. The maturation status was assessed by the presence of characteristic gametogenic stages categorized according to Paull et al [2008] and Geraudie et al [2009].…”