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Catch and Release...Doing it Right

By Sara Northrup, Research Biologist, FFSBC and Brian Chan , 🕔Wed, Feb 11th, 2015


Published in BC Outdoors Sport Fishing Magazine's Spring 2010 edition

British Columbia is blessed with diverse and abundant freshwater recreational fishing opportunities, many of which are considered world-class resources. Within the province one can find 200,000 lakes and over 750,000 kilometres of streams which support 24 species of freshwater game fish. Recreational freshwater fishing is popular with over 270,000 anglers participating in the sport in 2005. These anglers spent over 4 million days plying the lakes and rivers of the province. Every corner of the province offers fishing opportunities and they range from wilderness northern salmon and steelhead rivers, to urban lakes in greater Vancouver. The majority of our freshwater fisheries are based on stocks originating from wild fish resources, predominantly rainbow trout, cutthroat, steelhead, char and kokanee. There are fisheries for beginners to experts and everyone in between.

The 2005 survey of recreational fishing in Canada reported that anglers in BC caught over eight million fish, of which 74 percent were released. This survey, conducted every five years, continues to show the importance of both wild fisheries and the value of stocked lakes as a significant contributor to the overall angler effort generated each year. The Freshwater Fisheries Society of BC (FFSBC) releases approximately seven million fish each year into about 800 lakes located throughout the province. Annually, these 800 lakes support just over 50 percent of the total freshwater angling effort. The Ministry of Environment manages and maintains our freshwater fisheries resources for a diversity of sustainable fishing experiences that include consumptive and non-consumptive uses. A suite of fishing regulations are an important component of developing and implementing fishery plans throughout the province. Today, reduced catch limits, catch and release regulations and voluntary catch and release practices all play a role in the management of recreational fisheries.

Ongoing research is being conducted in BC and other jurisdictions concerning the impact of catching and releasing fish in small lakes, similar to those that form the backbone of our interior trout fishery. Catch and release fishing is undoubtedly a great conservation tool that allows for increased effort on lakes over traditional bag limits; however, just because fish are in the lake it does not mean that they are available to the anglers.

There are three main issues which anglers have to consider: the first, investigated be Sean Cox and Carl Walters, is that only a certain percentage of the fish stocked into the lake are considered "vulnerable" to angling due to their behaviour or location within the lake. The degree to which fish are unavailable depends on factors such as a lake’s topography or underwater structure. Brett van Poorten and John Post found changes in temperature and food availability affect feeding behaviour, which can also alter the susceptibility of fish to anglers.

A second issue is that as fish are captured and released, they become less susceptible to being caught the next time. Paul Askey suggested that the fish are learning how to avoid being recaptured. This means that although the number of fish remains high in the lake, catch rates can actually decrease as more and more fish 'learn' to avoid the hook.

The first few anglers to fish a population will generally experience exceptional catch rates, but angling quality for successive anglers declines rapidly even though the density of fish in the lake remains relatively constant. The rate at which fish learn is quite variable, as is the length of time required for the fish to 'forget' about the hook and come back to the fishery. Learned hook avoidance is common behaviour amongst sport fish but the degree of learning appears to be species and lake dependent. Variation in fishing method may decrease learning ability of fish.

A third issue that affects the angler is mortality of fish after they are released back into the lake. Although catch and release angling results in lower intentional mortality than bagging all fish captured, not all those released survive.

The practice of catch and release is most common in lakes and rivers that are managed for quality fishing experiences. Though, there are a growing number of anglers that have little desire to harvest a fish even in waters where it is legal. With catch and release fishing becoming more and more popular, the FFSBC has initiated a research project to better understand the implications of post-release mortality. The three main goals of the study were to: (1) identify the major factors contributing to catch and release mortality; (2) identify the impacts to the fishery due to mortality rates related to catch and release; and (3) increase anglers' understanding of the impacts of the activities.

FFSBC researchers have been estimating catch and release mortality of Blackwater, Pennask, and Tzenzaicut rainbow trout strains, comparing angling gear, seasons, and handling times. This work has been done in several lakes in BC over the last few years in an attempt to replicate real angling conditions. Our results have shown that although captured rainbow trout appear to look healthy when released, many of these fish were not alive several days later. Most mortality associated with the catch and release experiment occurred within the first 24 hours after release. The degree of mortality ranged from a minimum of 10 percent when conditions were favourable to a maximum of 38 percent (average 20 percent).

Mortality rates were most greatly influenced by water temperature, gear type, and the amount of time the fish was exposed to air. Aaron Bartholomew and James Bolsak found comparable results when reviewing several catch and release mortality studies on rainbow trout that found an average mortality rate of 19 percent (range 0-87 percent) depending on the variables tested. We found that the mortality rates for rainbow trout tend to be higher in lakes in late spring (25 percent) and throughout the summer (37 percent). On the other hand, mortality rates are reported to be much lower in rivers, perhaps due to colder water temperatures or higher dissolved oxygen. For example, D.J. Schill found mortality to be 4 percent in Badger Creek, Idaho.

Ideally, the management of catch and release fishing in BC’s stocked lakes requires either a strain of rainbow trout which has a high catchability factor combined with low leaning and low hooking mortality, or fisheries' managers and anglers working to address the issue of managing effort on some of our very high use waterbodies.

Better handling of fish that are intended for release can dramatically increase the survival and subsequent recapture rate of these fish. There are many factors that contribute to whether a released fish will survive. As mentioned some of the most important factors include water temperature, duration of fish, gear type, actual handling of fish and hooking location.

The length of time a fish is played and the temperature of the ambient water are major factors in the survival of a released fish. Water temperature is generally more of an issue in lakes, particularly productive lakes in the interior regions of the province, which attract significant angler effort. During late spring and the warm summer months the water above established thermoclines (the top 5 to 7 metres) can get quite warm with surface temperatures easily reaching 20 degrees Celsius (68 degrees Fahrenheit) while oxygen levels drop. The combination of lower oxygen levels and warm water temperatures has a significant impact when a fish is played for an extended period of time. Regardless of water temperature, fish should be played as quickly as possible. Once at the surface the fish can be netted or gently handled in the water while the hook is removed. A landing net makes the task of any fish handling much easier. Consider using a net that is big enough to hold the size of fish you could expect to catch. The netting should be made of a soft, non-abrasive, knotless material with mesh opening of less than 20 millimetres. Some net manufacturers utilize a soft rubber mesh for the net basket, which is also fish friendly.

Prior to landing the fish, wet the entire net bag to reduce loss of slime and scales. Keep the fish and net in the water during the hook removal process. Hooks located deep in the throat or in the gill arches should be left in place and the leader cut off as close to the hook as possible. The majority of hooks will fall out within a couple of weeks. Large fish can be kept calm by turning them upside down while in the net. Once the hook is out gently cradle the fish in the water until it swims away on its own. Support the fish by placing one hand under the pectoral fins (first set of fins behind the head) and forming a U shape for the body to sit in. With your other hand, gently grasp just ahead of the tail of the fish (the wrist) and with both hands in place keep the fish suspended below the surface of the water. Use the three-second rule for taking a picture of your catch. Have the camera ready, picture framed up and then quickly bring the fish out of the water for the shot. The fish should be fully supported in the horizontal position with one hand holding by the wrist and the other cradling behind the pectoral fins. The fish should not be out of the water for more than 3 seconds. Better yet, take a shot of the fish while being held in the water by the wrist or fully supported with both hands. A fish destined for live release should never be held in the vertical position by the gills or upside down by the tail. Both positions leave the body unsupported and can cause serious damage to internal organs. Handling of any fish should be done with wet hands or consider using a wet fish handling glove made of a soft, fine woven material that is smooth to the touch. Some handy tools to have on board or in your fishing vest are hemostats (surgical pliers) or a pair of needle nosed pliers that can be used to remove hooks as well as bend down the barb. Remember that all streams and rivers in BC and many lake fisheries have a single barbless hook restriction.

There is a lot of truth to the often-quoted saying that 10 percent of the fishermen catch 90 percent of the fish. Good anglers can catch a lot of fish and if the majority of these fish are released it can have an impact on general angler success in that particular waterbody throughout the remainder of the fishing season. Some of our best interior trout lakes see a lot of angler pressure and when the "bite" is on there can be very high catch rates and release rates. The learned response of fish is something we as anglers have to consider. In other words, if you are having a great day catching and releasing fish, we need to perhaps ask ourselves how many fish are enough and should we move on and leave some catchable fish for other anglers. Our actions do have an impact on how vibrant a fishery remains throughout the entire angling season.

With the growing trend among anglers to catch and release, unharmed, a part of their allowable catch it is important to please abide by the following:

  • Play and release fish as rapidly as possible. A fish played for too long may not recover.
  • Keep the fish in the water as much as possible. A fish out of water is suffocating. Internal injuries and scale loss is much more likely to occur when out of water.
  • Roll fish onto their backs (while still in the water). This may reduce the amount they struggle, therefore minimizing stress, etc.
  • Carry needle-nose pliers. Grab the bend or round portion of the hook with your pliers, twist pliers upside down, and the hook will dislodge. Be quick, but gentle. Single barbless hooks are recommended, if not already stipulated in the regulations.
  • Any legal fish that is deeply hooked, hooked around the gills or bleeding should be retained as part of your quota. If the fish cannot be retained legally, you can improve its chances for survival by cutting the leader and releasing it with the hook left in.
  • Nets used for landing your catch should have fine mesh and a knotless webbing to protect fish from abrasion and possible injury.
  • If you must handle the fish, do so with your bare, wet hands (not with gloves). Keep your fingers out of the gills and don’t squeeze the fish or cause scales to be lost or damaged. It is best to leave fish in the water for photos. If you must lift a fish then provide support by cradling one hand behind the front fins and your other hand just forward of the tail fin. Minimize the time out of the water and then hold the fish in the water to recover. If fishing in a river, point the fish upstream while reviving it. When the fish begins to struggle and swim normally, let it go.

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