Squaring the circle: Reconciling fishing and conservation of aquatic ecosystems

TY - JOUR

T1 - Squaring the circle

T2 - Reconciling fishing and conservation of aquatic ecosystems

AU - Law, Richard

AU - Kolding, Jeppe

AU - Plank, Michael J.

PY - 2015/3/1

Y1 - 2015/3/1

N2 - Size-at-entry regulations in fisheries cause major disruption to aquatic ecosystems, including truncation of age- and size-structures, destabilization of fish stocks, directional selection on phenotypic traits and a by-catch of unwanted species and sizes. Here, we use simple dynamic models of size-spectra to examine an alternative, so-called balanced harvesting. Balanced harvesting helps in retaining the approximate power-law size-structure of natural ecosystems, whereas size-at-entry regulations do not. Balanced harvesting is less likely to destabilize steady states than size-at-entry regulations set close to the size at maturation. Surprisingly, our numerical results suggest that steady-state biomass yield can be substantially increased by switching from size-at-entry to balanced harvesting. On the basis of these results, we argue that the goals of conservation and of greater yields seem less difficult to reconcile than have previously been thought. However, to work towards these goals require a change in our approach to fishing.

AB - Size-at-entry regulations in fisheries cause major disruption to aquatic ecosystems, including truncation of age- and size-structures, destabilization of fish stocks, directional selection on phenotypic traits and a by-catch of unwanted species and sizes. Here, we use simple dynamic models of size-spectra to examine an alternative, so-called balanced harvesting. Balanced harvesting helps in retaining the approximate power-law size-structure of natural ecosystems, whereas size-at-entry regulations do not. Balanced harvesting is less likely to destabilize steady states than size-at-entry regulations set close to the size at maturation. Surprisingly, our numerical results suggest that steady-state biomass yield can be substantially increased by switching from size-at-entry to balanced harvesting. On the basis of these results, we argue that the goals of conservation and of greater yields seem less difficult to reconcile than have previously been thought. However, to work towards these goals require a change in our approach to fishing.

KW - Balanced harvesting

KW - Fishing-induced instability

KW - Maximum sustainable yield

KW - Power-law size-structure

KW - Resilience

KW - Size-spectra

UR - http://www.scopus.com/inward/record.url?scp=84923084148&partnerID=8YFLogxK

U2 - 10.1111/faf.12056

DO - 10.1111/faf.12056

M3 - Article

AN - SCOPUS:84923084148

SN - 1467-2960

VL - 16

SP - 160

EP - 174

JO - Fish and fisheries

JF - Fish and fisheries

IS - 1

ER -