Age and growth of European barbelBarbus barbus(Cyprinidae) in the small, mesotrophic River Lee and relative to other populations in England

Abstract

Key-words:habitat, conservation, scale ageing, recruitment Suspected of being in decline, the European barbel Barbus barbus population of the River Lee, a heavily-modified river in South East England, has been the subject of investigations to identify factors associated with perceived population decreases. Population surveys between 1995 and 1999 captured a total of 912 individuals, and standard length (SL) frequency analyses between years suggested that the population decline was not related to juvenile recruitment but rather to a recruitment bottleneck in fish 300-340 mm SL. This bottleneck probably results from insufficient available habitat suitable to this size class. Of the sampled fish, scales were removed from 764 and were used in a scale ageing exercise among three researchers. Analyses of their independent age estimates revealed variable interpretations, which arose from uncertainties relating to the difficulty of analysing scale patterns from relatively large, slow-growing fish. Nevertheless, error was within published acceptable margins, and age estimates revealed B. barbus in the river to age 10 years, lower than in many UK rivers. The SL-at-age growth curve was characterised by very fast growth in the initial years of life. Thus, the causal factors in the decline of this B. barbus population appear to have been in the adult life-stage habitat and were likely related to the loss of longitudinal connectivity, mainly due to the presence of water retention structures. River and aquatic ecosystem remediation strategies should therefore focus on enhancing longitudinal connectivity in conjunction with the ongoing improvement of water quality and ecosystem integrity. Mots-clés :habitat, conservation, scalimétrie, recrutement Soupçonnée d'être en déclin, la population de barbeau européen Barbus barbus de la rivière Lee, une rivière fortement modifiée dans le Sud Est de l'Angleterre, a fait l'objet d'investigations pour identifier les facteurs associés à la diminution ressentie de la population. Le suivi de population entre 1995 et 1999 a permis la capture de 912 poissons, et l'analyse des fréquences de longueur standard (SL) entre années suggère que le déclin de la population n'était pas lié au recrutement des juvéniles, mais plutôt à un goulot d'étranglement du recrutement chez les poissons de 300-340 mm SL. Ce goulot d'étranglement résulte probablement d'une insuffisance de l'habitat disponible approprié pour cette classe de taille.

Growth of common carp Cyprinus carpio in Anatolia (Turkey), with a comparison to native and invasive areas worldwide

“…In this study, the VBGF satisfactorily described growth of common carp in Anatolia at the global, group (i.e., climate, water body, scalation variant, sex) and individual stock level, hence in accordance with recent findings supporting the validity of the model as a reliable descriptor of growth in fish (e.g., Pardo et al 2013). For this reason, although other curve fitting functions such as the logarithmic (e.g., Britton et al 2012;Vilizzi et al 2013a;Rypel 2014) could have been used, for the sake of both Table 3. Parameter estimates (AESE) (FL ∞ = asymptotic fork length, FL in mm; K = Brody growth coefficient, in years À1 ; t 0 = age of the fish at 0 mm FL; x = FL ∞ • K) of the coefficients for simple linear regression relationships of altitudinal and water temperature (T w ) gradients in growth performance (Φ', x) and mortality (M) parameters for common carp stocks (combined sexes only) of Anatolia.…”

“…; Vilizzi et al. ; Rypel ) could have been used, for the sake of both consistency with previous studies and convenience in obtaining readily interpretable and more widely applicable growth indices (Froese & Pauly ), the VBGF was chosen as the preferred function for modelling common carp growth in this study.…”

“…This is because growth correlates with a number of life-history traits including natural mortality rate (Pauly 1980), which is known to influence the response of a fish species to exploitation (Frisk et al 2005). In addition, comparative studies of freshwater fish growth at the regional (e.g., Britton et al 2012;Vilizzi et al 2013a), continental (e.g., Copp et al 2009a) and trans-continental (e.g., Copp et al 2004) scale have provided useful insights for the conservation of endangered species in their native areas of distribution as well as for the management and control of invasive species.…”

Influences of environmental and chemical parameters on the spatial growth patterns of four riverine cyprinid fishes

“…The first growth metric was the determination of the mean standardized growth residuals for each river per species (Jones, 2000;Benstead et al, 2007;Storm and Angillett, 2007). For each species, this required the length at age data for all rivers (restricted upper ages; rationale already described), with the mean length at each age determined using the log-log quadratic function of Vilizzi and Walker (1999) who identified this as the most precise and biologically meaningful growth model of five quadratic functions (Vilizzi et al, 2013). Whilst the von Bertalanffy growth model could have been used as an alternative for this, a preliminary examination of its use revealed 12p3 C. Liu et al: Knowl.…”

Polluted water exacerbates Barbus callensis oocyte oxidative status

“…In recent decades, stocks of barbel, Barbus barbus L. (Teleostei: Cyprinidae) have dramatically decreased throughout the world because of the deterioration and/or loss of microhabitats (Vilizzi et al 2006(Vilizzi et al , 2013. Moreover, Barbus barbus is an attractive sport fish which remains under strong angling pressure.…”