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Phone calls and fishing diaries: a survey among recreational sea bass fishers

How to quantify a recreational fishing activity which is far from negligible but widely scattered along the while coastline? An original statistical approach was designed to study the recreational sea bass fishery on the French Atlantic and Channel coasts.

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 The worldwide marine fish production yearly yields about 90 million tons. Yet this amount is underestimated as it often ignores discards and illegal catches, but also small-scale fisheries, recreational, sport and subsistence fishing. The importance of recreational fishing has long been thought to be negligible versus professional fisheries. According to regions and species, it can represent 10 to 64 % of the total production: it has thus become impossible to overlook it when it comes to stock assessment.

This rouses a growing interest from scientists, who are still facing the challenge of better knowing these fisheries and estimating their catches. Recreational fishermen are many and scattered, fish at highly variable times and frequencies and use a wide array of fishing gears. Their landings are not recorded and they are not always obliged to have a fishing license. Yet the European Commission requires the quantification of the recreational catches of some important species, among which sea bass, a highly prized species, particularly in France. This study thus dealt with the elaboration of a large-scale monitoring system of the recreational sea bass fishery, to determine its main characteristics and estimate its catches.

The methodology combined two large-scale telephone surveys with a fishing diary survey.

  • Sea bass phone survey
    From June to November 2009, 172.054 phone numbers were called by a polling institute in the Departments facing The Atlantic and the English Channel; 15.091 calls (9 %) lead to an interview and to the identification of 535 "sea bass fishermen" (defined as anyone having caught at least one sea bass during the last 12 months). 467 fishermen accepted to ask questions about their fishing practices.
  • Fishing diary survey
    256 fishermen accepted to voluntarily fill a diary on their fishing activity and their catches. 190 among them returned at least one fishing diary and 40 returned the whole-year set of diaries. Each fisherman was contacted every three months to get informed on the progress of the study and answer their questions.
  • Recreational fishing phone survey
    The results of a 2006 survey on recreational fishing were used to extrapolate to the whole metropolitan France the results of the sea bass survey which concerned only the coastal Departments, and to compensate some of its biases.


Sampling design of the sea bass survey

Recreational fishing for sea bass is done either from the shore or from a boat, most often with rods, with bait (40 % of the trips from the shore, 9 % from a boat) or with lure (52 % and 28 % respectively) and handlines (20 % in both cases). Longlines, spearguns and nets were much less used.

In the French Atlantic, the minimum legal catch size of the species was 36 cm at the time of this study, but recreational fishing federations generally recommended a minimum size of 42 cm (which is now the legal standard). The average length of sea bass caught by the panelists was 38 cm; they released at sea 88 % of the fish smaller than 36 cm and 48 % of those between 36 and 42 cm. On the average, 1.15 sea bass (953 g) were caught by trip. Boat trips yielded almost twice as much as shore trips, at least in terms of biomass (1221 g vs. 651 g). The mean hourly catch was 321 g and 0.41 fish, once again higher during boat trips. Fishing gears have different productivities in terms of number of fish or weight as they do not target the same size ranges: spearguns and nets catch large fish (mean lengths 53 and 51 cm) but in small numbers, whereas the opposite is true for longlines (mean length 36 cm).

It was estimated that 370.000 persons fish sea bass for their pleasure in the region covered by the study, during 2.1 million trips per year. They catch almost 4 million fish (weighing 3173 tons), but after he release of the smaller ones they land 1.9 million fish (2345 t). Fishers living in the coastal Departments caught two-thirds of this total. Rods with lure, rods with bait and handlines respectively represent 41, 20and 17 % of the trips, and the two kinds of rods respectively catch 1683 and 674 t. Compared to commercial fishing, the recreational sea bass fishing is far from negligible as it accounts for about 30 % of total landings.



Estimated yearly catches of the recreational fishing for sea bass

Although it brought much new information, the methodology used in this study faces some limits:
- some phone numbers are not accessible ("red list")
- an important proportion of persons did not accept to answer
- fishing diaries were completed on a voluntary basis
- many of them were not completed during the whole period of study
- the data recorded on the diaries were not controlled.

In most cases, statistical techniques made it possible to reduce the resulting biases. For instance, the weekly follow-up of 47 panelists (to fill in the diary with them) during 3 months showed that the risk of collecting incorrect or incomplete date (through omission of unsuccessful fishing trips or undersized fish, or under-reporting of a good catch) is very low.

In spite of these unavoidable limits, this approach is a cost-effective way to obtain data otherwise hard to collect; it also has other advantages, such as to foster the participation of fishers in recreational fisheries management. The survey thus showed that the recreational sea bass fishery is far from anecdotal and that its impact on the stock must be considered in the context of existing or future rules.


The paper

Rocklin D., Levrel H., Drogou M., Herfaut J., Veron G., 2014. Combining Telephone Surveys and Fishing Catches Self-Report: The French Sea Bass Recreational Fishery Assessment. PLoS ONE 9(1): e87271. doi:10.1371/journal.pone.0087271.

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The full paper (open access)

The authors

The co-authors of this paper work in the laboratory Amure of IUEM and in the 'Unité Sciences et Techniques Halieutiques of Ifremer. The first author presently is in a post-doctoral contract at the University of Murcia, in Spain.


The journal

The scientific journal PLoS One was created in 2006 and is original in two respects: it is exclusively published online (no paper version) and all its articles are open-access (free access, no subscription). It covers all disciplines and fields of research. It is published by PLoS (Public Library of Science), a non-profit organization based in the USA.



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