Effectiveness of Regulations to Sustain Sport Fisheries Across Landscapes

Studies suggest anglers allocate fishing effort across lake districts based on fishing quality and travel time and costs to access fishing.  As a result, the density of fishing effort tends to be highest near urban areas and declines with increasing distance from these areas. Landscape patterns in fishing quality reflect the pattern in effort, with high quality fisheries in remote areas and poor angling quality near large urban areas.  In this paper we explore the effectiveness of harvest regulation to counter this tendency for overfishing and stock collapse near population centres, and their ability to reverse declines in angling quality.  We use data from a rainbow trout fishery distributed across a large lake district in southern British Columbia, Canada, to model the interplay between fish populations, harvest regulations and the dynamic spatial response of angling effort to changes in angling quality.  Our results suggest that traditional harvest regulations, such as daily bag limits, can improve rainbow trout fishing quality if the latent effort from cities is not too high, but will fail to prevent collapses within regions closest to cities. Harvest regulations are unnecessary in fisheries distant from cities.  The ability of catch and release regulations to maintain quality fisheries is inversely related to the rate of mortality of released fish. Catch and release rainbow trout fisheries with a low release mortality rate (c.a. 5%) can maintain reasonable quality even close to large cities whereas higher release mortality (c.a. 20%), coupled with high latent effort near cities, does not prevent collapse.  Direct fishing effort limitation can maintain high quality fisheries, but a high proportional reduction in realized effort is required to maintain fishing quality near cities.  Short of severe effort limitation, urban and surrounding wild rainbow trout fisheries are incapable of maintaining viable fisheries and hatchery put-and-take may be required to provide angling opportunities. In summary, explicit consideration of location of individual fisheries within lake districts is key to designing effective management approaches to maintain quality angling opportunities.  Maintaining angling quality across landscapes will require a mixed management strategy involving spatial variation in the intensity of harvest control.