Science: The ability of anglers to identify salmon and trout

             The ability of Great Lakes anglers to accurately identify salmonid species has not been measured.  Boulby and Savoie (2011) conducted a study to determine the accuracy of salmonid identification by boat anglers in Lake Ontario.            

            Charter boat captains and non-charter boat anglers were interviewed after completed fishing trips as part of the Ontario Ministry of Natural Resources creel survey from April to September 1995 and from April to June 1996.  The anglers were asked for catch, effort, and harvest data and number of years experience fishing for trout and salmon in Lake Ontario.  They were also asked to identify the species of each fish harvested.  The creel survey technician also recorded their own species identification and fork length of each fish.  Accuracy was based on comparison of identifications between the anglers and the technician.  The investigators also determined if accuracy was related to years of experience or fish size.

            The overall accuracy of salmonid identification by charter boat captains for all salmon and trout was 96% and for non-charter boat anglers was 91%.  For charter boat captains, accuracy for Coho salmon Oncorhynchus kisutch and rainbow trout O. mykiss was 100%, Chinook salmon O. tshawytscha was 97%, lake trout Salvelinus namaycush was 96% and brown trout Salmo trutta was 86%.  For non-charter boat anglers, accuracy for lake trout was 96%, Chinook salmon was 93%, rainbow trout was 88%, brown trout was 85%, Atlantic salmon S. salar was 67% and Coho salmon was 60%.  Coho salmon were misidentified as Chinook salmon 34% of the time.  They were also misidentified as rainbow trout.  Rainbow trout were misidentified as brown trout and Chinook salmon.  Chinook salmon were misidentified as rainbow trout most of the time but also Coho salmon.  Atlantic salmon were misidentified as Chinook salmon.  Brown trout were misidentified as rainbow trout, Chinook salmon, lake trout and Coho salmon.  Lake trout were misidentified as brown trout, rainbow trout and Chinook salmon.

            For non-charter boat anglers, experience was not significantly related to accurately identifying most of the salmon and trout.  However, anglers with more than 8 years experience identified Coho salmon more accurately than less experience anglers.  Mean length of Chinook salmon was significantly greater for accurately identified individuals than misidentified individuals for both charter boat captains and non-charter boat anglers.  Length had no effect on the accuracy of identification of the other salmon and trout by non-charter boat anglers (sample size was from charter boat captains was too small for analysis of other salmon and trout species).

            Charter boat captains and non-charter boat anglers were highly accurate when identifying salmonids, despite a possible disincentive to learn how to identify each species.  In Lake Ontario, regulations limit anglers to harvesting an aggregate of five salmon or trout per day, which can include only three lake trout and one Atlantic salmon.  But most anglers only harvest three or fewer fish per day, so there is no need to be able to identify lake trout, Chinook salmon, Coho salmon, rainbow trout or brown trout.

            The high accuracy of salmonid identifications by anglers increases the usefulness of catch statistics calculated by the Ontario Ministry of Natural Resources.

Implications for anglers

            There are two points of which anglers should be aware. First, this study was conducted in the mid 1990’s.  The continuous enhancement of information technology has made materials about fishing, including species identification, more accessible to anglers.  Second, there is not an Atlantic salmon fishery in Lake Michigan.  Anglers on Lake Michigan only have to be able to identify five salmonids, instead of the six in Lake Ontario.  Given these two points, accuracy of salmonid identification is probably higher among anglers currently in southeast Wisconsin than anglers in the study.

            Proper identification of fish species is important for a number of reasons.  A large portion of the data used to manage salmon and trout stocks and determine stocking levels in Lake Michigan comes from charter boat captains and recreational anglers.  Accurate identification increases the reliability of data collected from anglers.  Also, Wisconsin fishing regulations allow anglers to keep two lake trout per day, so anglers need to be able to distinguish lake trout from the other salmonid species.  The ability to identify each species will also be helpful while participating in a fishing derby.  Small Chinook salmon are often confused with big Coho salmon.  You can save room in your bag limit by releasing small Chinook salmon, allowing you to fish longer and, hopefully, catch something worthy of the standings board. Misidentifying a small Chinook salmon ultimately leads to disappointment at the weigh-in.  You may also save yourself from throwing back a large Coho salmon after mistaking it for a small Chinook salmon.  Also, during multi-day fishing derbies, one species may be underrepresented on the board and any individual of the particular species will make the board, and possibly win a prize.  Having the ability to properly identify any of the Lake Michigan salmonids allows you to target the underrepresented species and get on the board.

Selected definitions

Catch: the amount of fish landed

Effort: the amount of fishing taken place

Harvest: the amount of fish taken for use, or not released

Creel survey: a sampling program that involves interviews and inspection of anglers’ catches

Fork Length: the distance between the tip of the snout and the most anterior point of the fork of the tail

Sample size: the number of observations in a study

Stock: a group of individuals of a species occupying a well-defined area independent of other groups of the same species and with a different gene pattern

Salmonid: a fish of the salmon family

Boulby, J.A. and P.J. Savoie. 2011. Verifying identification of salmon and trout by boat anglers in Lake Ontario. North American journal of fisheries management. 31:468-473