Shifting trophic architecture of marine fisheries in New Zealand: Implications for guiding effective ecosystem‐based management

Abstract

Variability in the abundance of commercial catches of fish has been studied for centuries (Huxley, 1881), especially in highly productive and highly populated regions (Heincke, 1898;Newland, 1999).Globally, abundance of fishing stocks has displayed declines over the past several decades (Worm et al., 2009), with changes in commercial fish assemblages identified for important fishing grounds

Stable isotopes of amino acids from reef fishes uncover Suess and nitrogen enrichment effects on local ecosystems

“…dependency on infaunal invertebrate prey, N. macropterus is highly susceptible to habitat degradation from trawling activities and overfishing. In fact, isotope values and TP results are consistent with the effects of increased fishing pressure as indicated by fish landing data for this species (Fisheries New Zealand 2019, Durante et al 2020a). During a period of large fisheries landings in the 1970s, the δ 13 C and δ 15 N values of N. macro pterus increased, while its TP decreased.…”

Changes in Trophic Structure of An Exploited Fish Community At The Centennial Scale Are Linked To Fisheries and Climate Forces

“…The system provides an ideal opportunity to estimate the effects of accelerations in these important anthropogenic stressors with changes in the trophic structure of large marine communities. For example, while worldwide marine fisheries landings have not shown significant increases between 1970 and 2018 4 , in 1970 New Zealand's landings were only 25% of those reported in 2018 21 .…”

“…For instance, overexploitation and ocean warming have had increasing influences on marine communities and ecosystem function over the last century 7,18,19 , with cumulative impacts observed across more than half of the global ocean 20 . In this context, long-term studies that incorporate archival samples to measure changes in trophic structure can provide important new insights into how the relatively recent history of human impacts have modified natural marine food webs [21][22][23] . New Zealand's relatively recent history of European settlement, which expanded in the early 1800's, and later fisheries industrialization provide an unparalleled opportunity to track the effects of anthropogenic impacts on its marine ecosystems 24 .…”

“…Although Māori established in New Zealand at least 700 years ago 25 , the level of fisheries exploitation before widespread European settlement is estimated to be significantly lower than that after the industrialization period 26 . These systems have undergone dramatic changes in recent decades 27 , with expansion and intensification of industrialized fisheries between 1970 and 2000 21 and increasing frequency of positive ocean temperature anomalies since 1996 22 (Fig. 1).…”

Maternal age, length, and weight influence larval characteristics and viability in the viviparous temperate reef fish Helicolenus percoides

“…While recognition of the relationships be tween maternal condition and larval survival has been demonstrated in the literature since the 1960s (Nikol'skii 1962), we have only re cently begun to incorporate these relationships into fisheries management considerations (Birkeland & Dayton 2005). Currently, fisheries management is moving away from the population-based, single-species approach (Botsford et al 1997), towards a multispecies fisheries management system, incorporating environmental and biotic factors, as well as variations in abundance, trophic structure, and demography within whole-fish communities (Pikitch et al 2004, Beddington et al 2007, Durante et al 2020. As part of the approach, population structure and maternal effects are now being recognized as important determinants of larval survival and recruitment success of marine populations (Hixon et al 2014).…”