Empirical observations and theoretical predictions show that fisheries can truncate target species size distribution by selectively removing larger individuals. It is less clear, however, how quickly populations revert to pre-harvest distributions after implementation of no-take policies by fisheries managers. In particular, the presence of a strongly interacting size-specific predator may interfere with the recovery of a targeted prey species. We used a two-species size-structured model to examine how gape-limited predation alters post-harvest recovery for three example species, cod, haddock, and whiting.
Results/Conclusions
We found that there was little difference in recovery time between the generalist predation and no-predation models. However, gape-limited obligate predation delays the recovery of large prey individuals to pre-harvest abundance, even for sizes not targetable by the predator. In addition, the obligate predator lowers the relative abundance of smaller vulnerable individuals, delays the shift to pre-harvest size distribution, and can complicate post-harvest monitoring through the presence of population cycles. We conclude that the presence of a strong dynamically-linked predator can interfere with the rapid recovery predicted from single-species management models, particularly for smaller-bodied fish with greater lifetime exposure to predation.