Fish market prices drive overfishing of the ‘big ones’

Athanassios C Tsikliras,Konstantinos Polymeros

doi:10.7717/peerj.638

Athanassios C Tsikliras, Konstantinos Polymeros

Open Access

https://doi.org/10.7717/peerj.638

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Abstract

The relationship between fish market price and body size has not been explored much in fisheries science. Here, the mean market prices and fish body size were collected in order to examine the hypothesis that large fish, both among- and within-species, are being selectively targeted by fisheries because they may yield greater profit. Trophic levels, vulnerability to fishing and global landings were also collected because these variables may also be related to the market fish price. These relationships were examined using generalized additive models (GAM), which showed that, among species, fish market price was positively dependent on maximum total length (P = 0.0024) and negatively on landings (P = 0.0006), whereas it was independent of trophic level (P > 0.05) and vulnerability to fishing (P > 0.05). When the fish price vs. size relationship was tested within-species, large individuals were consistently attaining higher market prices compared to their medium and small-sized counterparts. We conclude that the selective removal of the larger fish, which is driven by their market price and to a lesser extent by their availability, may contribute to their overfishing.

Highlights

Marine fish species account for over 80% of the total landings (Swartz, Sumaila & Watson, 2013) and a large proportion of them have been reported to be overexploited globally (e.g., Sumaila et al, 2012) and at various localities (e.g., Tsikliras, Tsiros & Stergiou, 2013)
In the present work we examine the relationship of fish market price with body size, trophic level, abundance and vulnerability to fishing in fresh marine finfish and examine which of these variables determine the price of fish
The generalized additive models (GAM) model results showed that there is a strong positive effect of Lmax (P = 0.0024) and a weaker positive effect of AI (P = 0.0006) on fish market price and that fish market price is independent of the trophic level and vulnerability to fishing (P > 0.05; Table 1, Fig. 1)

Summary

Introduction

Marine fish species account for over 80% of the total landings (Swartz, Sumaila & Watson, 2013) and a large proportion of them have been reported to be overexploited globally (e.g., Sumaila et al, 2012) and at various localities (e.g., Tsikliras, Tsiros & Stergiou, 2013). Fish market prices are among the economic drivers that affect fishers’ behaviour and, in particular, the selection of target species. Given that, according to economic theory, fishers make decisions based on potential profit (Brown, 2000), variations in price may make the fishing of a particular species more or less attractive (Holley & Marchal, 2004). Fish species attaining higher market price (i.e., those with higher potential profit) are targeted first (Sethi, Branch & Watson, 2010).

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