RECREATIONAL FISHERY ASSESSMENT METHODS

17.3 RECREATIONAL FISHERY ASSESSMENT METHODS

An integral part of the management of recreational fisheries is an understanding of the status of the resources in terms of fish stock structure, the value of fishing to the anglers, and to the local and regional economies, and, perhaps most impor- tantly, of end-user satisfaction. This information is required both to formulate management measures and to assess the impact of management policy on the fishery performance. For exploited natural stocks, annual assessment of the stock status through catch-and-effort sampling appears acceptable, whereas put-and-take fisheries need weekly monitoring for angler satisfaction and stock depletion, so that management can respond quickly to any measured deterioration in either characteristic. For unexploited stocks in catch- and-return fisheries, trends are usually the main requirement.

Surveys to collect this type of information are generally constrained by money and manpower, and the degree of precision required in the infor- mation collected to meet management objectives (Cowx 1996). Problems are also encountered in the assessment of the economic status because of the difficulty of putting value on non-tangible resources. Several methods have now been devel- oped to overcome these problems and provide

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baseline information on which management Moore 1998). However, it should be recognized policy can be formulated.

that each approach has distinct advantages and Two distinct strategies for obtaining the infor- biases over the other (see Table 17.1). mation from anglers are used (Malvestuto 1983;

Off-site event recall methods tend to make use Pollock et al. 1994; Cowx 1996):

of lists of names of anglers, perhaps those in receipt • off-site event recall methods such as log books, of a fishing licence or permit, or boat licence, from mail questionnaires and phone surveys, which which a random sample is selected to provide the require the angler to evaluate the fishing experi- necessary information, or they make use of obliga- ence some time after the event (e.g. Axford 1991; tory returns of information linked to the issuing Beaumont et al. 1991; Bunt 1991; Churchward and of licences. Mail and telephone surveys tend to Hickley 1991; Cowx 1991; Gardiner 1991; Gerard

be low cost and can have a regional coverage, but and Timmermans 1991; O’Hara and Williams suffer from biases associated with non-response, 1991; Small 1991).

vagaries of recall and memory, angling prestige and • on-site intercept methods such as aerial count enthusiasm (Bunt 1991; Churchward and Hickley methods, access point methods and roving creel 1991; Dekker 1991; Gardiner 1991; Löffler 1991; methods, which collect information at the time of Small 1991). the event or immediately following it (e.g. Cryer

Dependence on lists of names also has biases: and MacLean 1991; Gerard and Timmermans for example, not all anglers may be required to 1991; Malvestuto 1991; Pawson 1991).

have licences, especially when sea fishing. To Information collected by either method can in- obtain acceptable data, the recall time interval clude total weight of catch, weight or number of should be kept to a minimum (<2 months pre- each fish species caught, time of day spent fishing, ferred) and the questions need to be simple. If at all duration of fishing experience in terms of number possible, the participants should be encouraged to of man-hours or other unit of effort, location of complete the questionnaires at the time of the fishing and method of fishing. These data are used fishing experience, i.e. set up a fishing diary or to determine the catch per unit of effort, usually logbook, although these too can be biased. Licence represented as g man-hr -1 , fish man-hr -1 or similar returns overcome some of the problems of random measure. In addition, the survey methods can be sampling but, despite statutory obligations, still used to collect information to determine the value suffer from non-response and recall biases. The of the fishery, using contingent valuation method- non-response can be minimized by sending out ologies or other similar techniques (Pollock et al. reminders, but rarely is a 100% return rate 1994; Gautam and Steinback 1998; Postle and achieved.

Table 17.1 Advantages and disadvantages associated with event recall and on-site intercept approaches for recreational fishery assessment.

Disadvantages Event recall methods

Approach

Advantages

Low cost

Non-response

Regional coverage

Recall bias

Immediate response (phone surveys)

Digit bias Prestige bias Avidity bias

On-site intercept methods

Minimization of response biases

High cost

Visual assessment of information exchange

Biases based on survey design Interruption of angling experience

On-site intercept methods minimize the biases associated with event recall methods because they have a high response rate, they allow direct infor- mation exchange which can be confirmed by the interviewer, and anglers are not required to recall catch information. Disadvantages are the high cost per angler interview, difficulties in contacting

a representative sample of anglers in a large geo- graphical area, and reliance on a random stratified survey design, similar to that used for commercial fisheries, which may introduce biases associated with the estimator used. With roving surveys, the interviewer contacts the anglers as he moves around the fishing area along a predetermined route. The primary weakness of roving survey methods is that catch-and-effort information is based on incomplete rather than complete fishing trips, because anglers are contacted while they are fishing. In access point surveys, the interviewer is stationed at a strategic site such as a car park, jetty or boat landing beach used by anglers, preferably at the end of the fishing trip. The surveyor then ran- domly selects a predetermined number of anglers for questioning. The access point survey is ideal where the anglers must leave via a small number of points or where anglers report their catches at a central location. Although the complexity of the questions in on-site methods can be increased it should not be so great as to interfere with the angler experience. On-site methods can also be combined with aerial surveys, boat counts or bank angler counts to determine the total fishing effort and assess the actual exploitation patterns.

To ensure accuracy of the data retrieval, several important aspects should be addressed (Cowx 2001). • Event recall methods must be validated with respect to the accuracy of the responses. Calibra- tion with on-site survey data is one option. • On-site intercept methods must be evaluated with respect to field techniques and design effi- ciency. New design alternatives must be devel- oped, particularly with respect to obtaining precise estimates of catch rate. • Indices which truly reflect the quality of the fishery from the angler’s point of view must be developed, and used for justification and evalua-

tion of management programmes. Lorenz curves, which quantify the probability of catching a certain number or weight of fish (O’Hara and Williams 1991), or the utility-per-recruit concept of Die et al. (1988), which uses an objective measure of angler satisfaction in place of catch weight in the usual yield-per-recruit model (Shepherd and Pope, Chapter

8, this volume), are good examples of this approach. • The use of catch per unit effort (CPUE) as an index of change in stock abundance for recrea- tional resources must be evaluated, particularly for those fisheries where fluctuations in stock size and high rates of exploitation are critical factors related to efficient functioning and the economic value of the fishery (put-and-take systems). Many of the methods introduced above tradition- ally focus on estimation of the biological para- meters, i.e. catch, effort and CPUE related to fishery. However, in recent years there has been an increasing need for valuation of the economic and social benefits of recreational fisheries to justify their position in a wider multiple resource-user environment (Cowx 1998b). As already indicated, this is a complex problem because it is difficult to put value on non-tangible recreational resources. Nevertheless several approaches, which can be built into the traditional angler intercept and event recall methods, have been developed to overcome these problems (Table 17.2).

Reviews on how to use these approaches are given by Pollock et al. (1994) and Weithman (1999). However, in general terms, the gross economic value of a recreational fishery is composed of: (1) explicit costs of local, regional and national ser- vices which contribute directly to the angler; (2) total angler expenditures directed towards the fishery, derived from licence and permit fees, equipment and travel costs; (3) the value over and above the actual expenditures that anglers would

be willing to spend to fish; and (4) the additional value based on non-users’ willingness to pay to preserve the fishery (Malvestuto 1983; Weithman 1999). On-site intercept and event recall methods can be used to provide estimates of average expen- diture per angler-trip or over a defined period, by asking the appropriate questions. The same sur- veys can be used to provide information on the net

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Table 17.2 Methods of assessing fishery benefits. (Source: after Weithman 1999.) Benefit measurement

Approach

Non-monetary Social well-being

Angler survey on changes in a fishery

Psychophysical measures

Angler survey on aesthetic appeal

Multi-attribute choice approach

Angler survey on a variety of fishery characteristics

Attitude measures

Angler survey of factors that affect the quality of fishing

Social impact assessment

Projection of changes that will likely result from a new policy

Monetary Economic impact assessment

Angler expenditure used as input for regional economic models

Economic value assessment Angler expenditure used as input for travel cost or contingent valuation Total economic valuation

Angler expenditure used as input for contingent valuation, plus non-consumptive user values Combination

Total value assessment Comprehensive evaluation that combines non-monetary and monetary evaluations to determine

social and economic values

willingness to pay, often defined as consumer Table 17.3 Interventions used in the management of surplus, using contingent valuation or travel cost recreational fisheries. methodologies (Pollock et al. 1994; Baker and Pierce 1997; Postle and Moore 1998). This will pro-

Fish stock

vide an economic value of angling to the region or Restocking to enhance stock the value individuals place on the fishery, and they Introductions to increase species diversity

Culling to remove predators and pest species can be used as persuasive arguments for the main-

tenance and improvement of the fishery. Fishery

Closed seasons Closed areas