Shifted baselines 387
mentioned increased difficulty catching large predators, smaller body sizes of species, depletion of fishing grounds, and the need for advanced technology and increased effort compared to their earlier experiences. When discussing these changes eight respondents independently described the 1980s and 1990s as a benchmark for ecosystem health, referring to higher abundances of marine animals, larger fish, less fishing pressure, and healthier coral. For example, when describing parrotfish abundance on Barbuda, one interviewee said, ‘the population was very high back in the 1980s and 1990s’ and also indicated that individual size had decreased over this same time period. OnMontserrat in par- ticular interviewees used the ecosystem before the volcanic eruption as a baseline against which to compare current abundance. For example, interviewees would commonly say ‘since the volcanic crisis, [the abundance of snapper] is not the same.’ This decadal timescale is relevant because two major events occurred that affected local reefs: the Caribbean-wide Diadema die-off in 1982 and the volcanic eruption in 1995. This date range indicates that interviewees are locating their views of pristine reefs between these two major disturbance events.
Evidence for a shifted baseline among resource users
We found strong evidence for a shifted baseline in resource users’ perceptions of the extent and degree of declines, with experience rather than age being the key determinant of perception of decline, and with no difference between fishers and divers. Notably, interviewees with ,15 years of experience reported amedian of 0.67 species as depleted, whereas interviewees with .30 years of experience re- ported a median of 6.00 taxa as depleted (Fig. 2a). The difference in median number of species mentioned as declining was significant across all experience levels (F(2,37)= 22.28,P,0.01). Our second metric of the shifting baseline syndrome
was the perception of the current abundance for the five taxa most commonly cited as declining (coral, lobster, conch, parrotfish and grouper). Interviewees with more experience were more likely to consider these five taxa as being less abundant; interviewees with ,30 years of experience typically described the key taxa as common (a rating of 3)comparedtothose with.30 years of experience, who described the same taxa as rare (a rating of 2, Fig. 2b). Only interviewees with high levels of experience described any of the five key taxa as absent (rating of 1), whereas only those with medium and low levels described any taxa as superabundant. Mean abundance rankings were signifi- cantly different only between interviewees with low and high levels of experience (t(df) = 235.51,P = 0.05). There were no significant differences across age categories in per- ceptions of either extent or degree of change.
FIG. 2 (a) Number of taxa perceived to be declining, and (b) perceived current abundance of the five taxa most cited as declining: coral (Scleractinia), lobster Panulirus argus, conch Strombus gigas, parrotfish (Scarus spp.), and grouper (Epinephelinae). Rankings are as follows: 1, absent; 2, rare; 3, common; 4, abundant; 5, superabundant. Respondents are grouped by years of fishing or diving experience (,15, 15–30 and .30 years). The horizontal line represents the median, the box the first and third quartiles, and the caps the range of responses.
The policy placebo effect
In addition to this shifted baseline,we identified whatwe term a policy placebo effect, in which recent local conservation ef- forts and new legislation result in the impression that taxa have increased in abundance before that is reasonably possible given the characteristics of the species. A subset of our inter- viewees reported that several key taxa (turtles, lobster, group- er, parrotfish and conch) had increased in abundance in recent years, which was frequently ascribed to new legislation and other local conservation efforts (Table 3). This perceived association wasmost striking for turtles, with half of intervie- wees mentioning that local turtle populations are increasing in response to conservation efforts. These conservation pro- grammes and legislation include a size limit and closed season on Montserrat, which was implemented in 2002 (14 years prior to interviews), and a turtle hatchery and a closed season on Antigua and Barbuda, which both began in 2013 (3 years prior to interviews).However, green turtles have a generation
Oryx, 2020, 54(3), 383–391 © 2018 Fauna & Flora International doi:10.1017/S0030605318000169
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