Generation-scale movement patterns of cutthroat trout (Oncorhynchus clarkii pleuriticus) in a stream network

Abstract

Movements by stream fishes have long been the subject of study and controversy. Although much discussion has focused on what proportion of fish adopt mobility within particular life stages, a larger issue involves the lifetime movements of individuals. I evaluated movements of different sizes and ages of Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) using a variety of sampling methods from 1996 to 2001 in a 40 km network of main-stem and tributary segments of the North Fork Little Snake River, Wyoming, USA. The probability of movement was related to the period of observation, initial location, and possibly individual growth rate, whereas distance moved was related to fish size and initial location. Furthermore, it appeared that movements by juveniles were mostly downstream, whereas those of older fish were largely upstream. Movement of cutthroat trout in this basin appeared to be driven by ontogenetic changes in habitat use and variation in habitat productivity. Given that this stream network exemplifies the complexity typical of many mountain watersheds, movement as a life history tactic in fishes may be more common than is sometimes recognized.Résumé : Les déplacements des poissons d'eau courante ont depuis longtemps été l'objet d'études et de controverses. Bien qu'une partie importante de la discussion ait porté sur la proportion de poissons qui deviennent mobiles aux différents stades de leur cycle, un problème plus large concerne les déplacements des individus au cours de leur vie entière. Une variété de méthodes d'échantillonnage de 1996 à 2001 sur un réseau de 40 km de segments du cours principal et des tributaires de la North Fork de la rivière Little Snake, Wyoming, É.-U., a permis d'évaluer les déplacements des truites fardées du Colorado (Oncorhynchus clarkii pleuriticus) de différents âges et tailles. La probabilité de déplacement est liée à la période d'observation, à l'emplacement initial et possiblement aussi au taux individuel de croissance, alors que la distance du déplacement est reliée à la taille du poisson et à la position initiale. De plus, il semble que les déplacements des juvéniles se font surtout vers l'aval, alors que ceux des poissons plus vieux ont lieu en grande partie vers l'amont. Les déplacements de la truite fardée dans le bassin semblent s'expliquer par des changements ontogénétiques dans l'utilisation des habitats et par la variation dans la productivité de ces habitats. Comme ce réseau hydrographique est un exemple typique de la complexité de plusieurs bassins versants de montagne, le déplacement comme tactique au cours du cycle biologique des poissons pourrait être beaucoup plus répandu qu'on le reconnaît quelquefois.[Traduit par la Rédaction]

Dispersal of larvae ofMargaritifera laevisby its host fish

“…Atlantic salmon ceased feeding at temperatures >24°C, and they moved to cooler streams during warm conditions (Cunjak et al 2005, Breau et al 2007, 2011. Our results suggest that Masu Salmon also seek thermal refugia in small streams during summer (see also Inoue et al 1997).…”

“…A similar pattern has been observed for Margaritifera margaritifera (Young andWilliams 1984, Österling et al 2008), but this contrasts with mussel species in the family Unionidae that typically parasitize a lower percentage of the available host resource (Neves and Widlak 1988, McLain and Ross 2005, reviewed by Strayer 2008. The high prevalence of Margaritiferidae glochidia on hosts may be explained by their occurrence in very dense beds, their extraordinarily high fecundity (∼10 6 glochidia/adult; Bauer 1994, Kondo 2008, Haag 2012, and the synchronous release of glochidia (Young and Williams Table 2.…”

“…The 1 st process is dispersal to upstream reaches. Adult mussel movement is limited to a few meters (Negishi et al 2008), so downstream drift of glochidia and juveniles will tend to deplete upstream populations (see Fagan 2002), and longterm population persistence probably is dependent on upstream movements of salmon hosts (see Gowan and Fausch 1996, Morrissey and Ferguson 2011, Young 2011. The 2 nd process is dispersal to heterogeneous habitats (Crozier andZabel 2006, Rogers andSchindler 2008).…”

Fish movement in an Atlantic Forest stream

“…Gowan et al (1994) found, for example, that streamdwelling fish can move long distances when conditions in their present foraging location become sub-optimal relative to conditions at other locations in the same reach. Movement was shown to be required for reproduction, dispersing to new habitats, or avoiding adverse habitat or resource conditions (Bryant et al, 2009;Flecker et al, 2010;Young, 2011).…”

“…Gowan et al, 1994;Bryant et al, 2009;Flecker et al, 2010;Young, 2011), the number of studies on this topic has increased, however mainly in temperate regions (e.g. Schlosser, 1991).…”