BackgroundFerox Trout are large, long-lived piscivorous Brown Trout (Salmo trutta). Due to their exceptionally large size, Ferox Trout are highly sought after by anglers while their life-history strategy, which includes delayed maturation, multiphasic growth and extended longevity, is of interest to ecological and evolutionary modelers. However, despite their recreational and theoretical importance, little is known about the typical abundance of Ferox Trout.MethodsTo rectify this situation a 16 year angling-based mark-recapture study was conducted on Loch Rannoch, which at 19 km2 is one of the largest lakes in the United Kingdom.ResultsA hierarchical Bayesian Jolly-Seber analysis of the data suggest that if individual differences in catchability are negligible the population of Ferox Trout in Loch Rannoch in 2009 was approximately 71 fish. The results also suggest that a single, often unaccompanied, highly-experienced angler was able to catch roughly 8% of the available fish on an annual basis.DiscussionIt is recommended that anglers adopt a precautionary approach and release all trout with a fork length ≥400 mm caught by trolling in Loch Rannoch. There is an urgent need to assess the status of Ferox Trout in other lakes.

The population status of salmonids is often assessed as ova deposition relative to “ova conservation densities.” Traditional approaches to assessing ova deposition predict log(ova numbers) from log(female length) for Atlantic salmon Salmo salar based on calibrations for unspawned females. Better ova deposition predictions are obtained by using both female length and female mass, especially when part‐spawned females arrive at or leave local study sites, which are crucial to parameterizing such relationships. Improved estimates of ova deposition could help reduce the noise in crucial stock–recruitment relationships and thus improve both mortality estimates at other life stages and management understanding.Received August 23, 2011; accepted January 12, 2012

Background. Ferox Trout are large, long-lived piscivorous Brown Trout (Salmo trutta). Due to their exceptionally large size, Ferox Trout are highly sought after by anglers while their life-history strategy, which includes delayed maturation, multiphasic growth and extended longevity, is of interest to ecological and evolutionary modelers. However, despite their recreational and theoretical importance, little is known about the typical abundance of Ferox Trout. Methods. To rectify this situation a 16 year angling-based mark-recapture study was conducted on Loch Rannoch, which at 19 km 2 is one of the largest lakes in the United Kingdom. Results. A hierarchical Bayesian Jolly-Seber analysis of the data suggest that if individual differences in catchability are negligible the population of Ferox Trout in Loch Rannoch in 2009 was approximately 71 fish. The results also suggest that a single, often unaccompanied, highly-experienced angler was able to catch roughly 8% of the available fish on an annual basis. Discussion. It is recommended that anglers adopt a precautionary approach and release all trout with a fork length ≥ 400 mm caught by trolling in Loch Rannoch. There is an urgent need to assess the status of Ferox Trout in other lakes.

Alternative routes to piscivory: Contrasting growth trajectories in brown trout (Salmo trutta) ecotypes exhibiting contrasting life history strategies. ECOLOGY OF FRESHWATER FISH.

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