The San Juan arm is primarily inundated canyon however, most fish contacts occurred in shallow coves and shoreline with thick stands of flooded salt cedar in the upper inflow area. Fish were released at 2 sites, and 9 made extensive up- and downstream movements (χ̄ = 47.8 km contact was lost with 4, and 4 others presumably died or lost their transmitters). Seventeen subadult, hatchery-reared razorback suckers (Xyrauchen texanus (χ̄ = 456 mm total length) were implanted with sonic transmitters and tracked for 23 months in the lower 89.6 km of the San Juan River (San Juan arm of Lake Powell, Utah). The extensive migratory behaviour of lake sturgeon within the studyĪrea make it prone to impingement or entrainment whereas the altered river flow appears to enhance reproductive development. Has complex effects on sturgeon in the Mattagami system. Levels by September reproductive hormones were at prespawning levels by the end of June. In contrast, male lake sturgeon began testicular recrudescence within one month of spawning with the GSI reaching prespawning Was not evident until September and was characterized by an increased GSI and plasma levels of testosterone and 17β-estradiol. Female sturgeon exhibited a prolonged period of ovarian regression following spawning. Gonadosomatic index (GSI) and plasma sex steroid hormone levels revealed a divergent pattern of reproductive development between Range of reproductively active fish, found in the vicinity of suitable spawning habitat during early May. There was a high proportion of fish (about 50%), within the size Groundhog River which is a tributary of the Mattagami River. Sites in the spring, a post-spawning dispersal to feeding areas and late summer migration to an area of concentration on the This distribution was related to the migration of individuals to potential spawning Tracking and the systematic sampling of lake sturgeon using gill nets indicated that the distribution of fish throughout the This study was conducted in order to evaluate seasonal migratory behaviour and reproductive pattern of lake sturgeon in aĬonfined region of the Mattagami River system in northern Ontario where river flow is regulated by hydroelectric works.

Fish heads navajo dam