Release Angling Research Articles

Physiological effects of catch and release angling in Atlantic salmon (Salmo salar) at different stages of freshwater migration

Nous avons etudie les effets de l'epuisement de saumons atlantiques (Salmo salar) unibermarins captures a la ligne et fatigues par la pecheur; des poissons ont ete pris a deux etapes de leur migration en eau douce. Nous avons compare les desequilibres physiologiques chez des charognards qui retournaient en mer apres une longue periode de jeune a ceux observes chez des saumons argentes qui avaient recemment penetre en eau douce. Les saumons argentes etaient en bien meilleur etat que les charognards et il fallait beaucoup plus de temps pour les epuiser apres qu'ils aient mordu a l'hamecon. La concentration de la phosphocreatine et celle du glycogene dans le muscle blanc s'abaissaient immediatement apres la capture chez les deux groupes, mais se retablissaient plus rapidement chez les charognards. La concentration du lactate dans le meme tissu passait par un maximum de 22,2 mmol.L -1 d'eau tissulaire apres la capture chez le charognard et de 40,6 mmol.L -1 d'eau tissulaire chez le saumon argente. En outre, l'acidose intracellulaire mesuree dans le muscle blanc apres la capture etait plus marquee chez le argente. Enfin, aucun des 24 charognards captures n'est mort, mais 3 des 25 saumons argentes sont morts dans les 12 qui ont suivi leur capture. Au bilan, ces resultats montrent que les charognards sont moins perturbes par leur capture, sur le plan physiologique, que les saumons argentes.

Physiological effects of catch and release angling in Atlantic salmon (<I>Salmo salar</I>) at different stages of freshwater migration

Physiological effects of catch and release angling in Atlantic salmon (<I>Salmo salar</I>) at different stages of freshwater migration

Effects of late-season catch and release angling on anaerobic metabolism, acid–base status, survival, and gamete viability in wild Atlantic salmon (Salmo salar)

The effects of catch and release angling on muscle physiology, survival and gamete viability were examined in wild Atlantic salmon (Salmo salar), just prior to spawning. Lactate in the white muscle increased to 37.4 μmol∙g−1after angling and recovered within 4 h. Muscle pH decreased from 7.46 at rest to 6.80 following angling, but returned to resting levels within 2 h. White muscle concentrations of PCr, ATP, and glycogen were depleted by 74, 46, and 73%, respectively, following angling. ATP and PCr returned to resting levels within 2 h, but glycogen did not recover until 12 h. The absence of significant changes in blood glucose indicated that the stress response was minimal in salmon angled under these conditions (6 °C). There were also no mortalities among 20 salmon that were angled and transported to the hatchery. Multi-sea-winter (MSW) salmon (> 63 cm) required a longer period to angle to exhaustion than grilse (< 63 cm), but the physiological disturbance was less in MSW salmon. The survival of eggs from angled and nonangled salmon was 98 and 97%, respectively. Together, these results support the strategy of a late-season catch and release fishery for Atlantic salmon.

Effects of capture and recovery on plasma levels of cortisol, lactate and gonadal steroids in a natural population of rainbow trout

Rainbow trout were captured by angling from a run of spawning fish on the Tongariro River in northern New Zealand, to examine the effects of catch and release angling on stress and reproductive parameters. Fish were blood sampled immediately after capture at playing times of <5 or 15 min, or after 1 or 24 h of recovery in stream enclosures. Plasma samples were assayed for cortisol (F), lactate, testosterone (T), 17β‐oestradiol (E2), and 17a,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20βP). Plasma F levels were similar to those of hatchery stocks of rainbow trout, at capture, and became significantly elevated 1 h after capture. Plasma F was still clevated in some fish 24 h after capture. Plasma lactate levels began to increase 15 min after capture, were further elevated 1 h after capture, and had returned to normal 24 h after capture. We proposed that metabolic recovery had occurred but that some animals were still experiencing some degree of stress, possibly in response to holding conditions in the river. Both plasma T and E2 were depressed 24 h after capture, whereas there was no change in plasma 17,20βP. This is consistent with other findings showing that acute stress is associated with depression of plasma levels of T and E2. There was no mortality as a result of capture or any of the handling protocols. We conclude that catch and release angling will result in negligible mortality, but may have an inhibitory effect on some reproductive processes.