The global contribution of forage fish to marine fisheries and ecosystems

543

446

Data from 4,713 fisheries worldwide, representing 78% of global reported fish catch, are analyzed to estimate the status, trends, and benefits of alternative approaches to recovering depleted fisheries. For each fishery, we estimate current biological status and forecast the impacts of contrasting management regimes on catch, profit, and biomass of fish in the sea. We estimate unique recovery targets and trajectories for each fishery, calculate the yearby-year effects of alternative recovery approaches, and model how alternative institutional reforms affect recovery outcomes. Current status is highly heterogeneous-the median fishery is in poor health (overfished, with further overfishing occurring), although 32% of fisheries are in good biological, although not necessarily economic, condition. Our business-as-usual scenario projects further divergence and continued collapse for many of the world's fisheries. Applying sound management reforms to global fisheries in our dataset could generate annual increases exceeding 16 million metric tons (MMT) in catch, $53 billion in profit, and 619 MMT in biomass relative to business as usual. We also find that, with appropriate reforms, recovery can happen quickly, with the median fishery taking under 10 y to reach recovery targets. Our results show that commonsense reforms to fishery management would dramatically improve overall fish abundance while increasing food security and profits.fishery recovery | fishery reform | rights-based fishery management | bioeconomic model

Section: Methodsmentioning

confidence: 99%

Global fishery prospects under contrasting management regimes

Costello

Ovando

Clavelle

et al. 2016

543

446

“…B t+1 = B t + SP t − F t B t , if B t > 0:5 B t + SP t , otherwise , [2] where B t is stock biomass, SP t is the surplus production, and F t is the fishing mortality rate in year t. SP t was calculated from the time series of biomass and catches. We projected population biomass forward 10 y starting with the first year that B < 0.5.…”

Section: Methodsmentioning

confidence: 99%

Fishing amplifies forage fish population collapses

Essington¹,

Moriarty²,

Froehlich³

et al. 2015

240

190

Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.marine conservation | population collapse | fisheries | ecosystem-based management

“…Although not explicitly shown by Essington et al (4), it is reasonable to expect substantial benefits of this harvest strategy to the broader ecosystem, given the critical linkages between forage fish and other species (2,3,8). Long-term empirical studies have demonstrated that seabird breeding success (and ultimately population size) declines precipitously as the abundance of their forage fish prey decreases and foraging time increases (9,10).…”

Section: Fishing's Fingerprintmentioning

confidence: 98%

“…Forage species play an essential and valuable supporting role within marine ecosystems by serving as prey for larger species (2,3). These findings underscore the importance of (i) furthering understanding of the determinants of forage fish collapses, and (ii) of devising exploitation strategies that will maintain their crucial ecological and economic roles.…”

mentioning

confidence: 99%

Stop-loss order for forage fish fisheries

Pikitch

2015

Recent literature has highlighted the exceptional importance of forage fish, which include some of the largest fisheries in the world and produce a sizeable share of the global wild marine fish catch (1). Forage species play an essential and valuable supporting role within marine ecosystems by serving as prey for larger species (2, 3). These findings underscore the importance of ( i ) furthering understanding of the determinants of forage fish collapses, and ( ii ) of devising exploitation strategies that will maintain their crucial ecological and economic roles. Essington et al. (4) significantly advance understanding on both counts, applying novel methods to uncover fishing’s fingerprint in regulating population fluctuations and demonstrating the effectiveness of a simple remedy to prevent collapses.