Climate vulnerability and resilience in the most valuable North American fishery

Abstract

Managing natural resources in an era of increasing climate impacts requires accounting for the synergistic effects of climate, ecosystem changes, and harvesting on resource productivity. Coincident with recent exceptional warming of the northwest Atlantic Ocean and removal of large predatory fish, the American lobster has become the most valuable fishery resource in North America. Using a model that links ocean temperature, predator density, and fishing to population productivity, we show that harvester-driven conservation efforts to protect large lobsters prepared the Gulf of Maine lobster fishery to capitalize on favorable ecosystem conditions, resulting in the record-breaking landings recently observed in the region. In contrast, in the warmer southern New England region, the absence of similar conservation efforts precipitated warming-induced recruitment failure that led to the collapse of the fishery. Population projections under expected warming suggest that the American lobster fishery is vulnerable to future temperature increases, but continued efforts to preserve the stock's reproductive potential can dampen the negative impacts of warming. This study demonstrates that, even though global climate change is severely impacting marine ecosystems, widely adopted, proactive conservation measures can increase the resilience of commercial fisheries to climate change.

Fishing constrains phenotypic responses of marine fish to climate variability

“…However, despite the wealth of work undertaken in marine environments on the causes of longer‐term biological change, the effects of these two drivers have traditionally been considered in isolation, and when in concert only at the population scale (e.g. Perry et al, ; Planque et al, ; Kjesbu et al, ; Le Bris et al, ). Here, we show that fishing can induce shifts in purple wrasse individual‐level biocomplexity, namely the expression of growth thermal reaction norms.…”

The brighter side of climate change: How local oceanography amplified a lobster boom in the Gulf of Maine

“…The thermally mediated dilution hypothesis is not the only potential explanation of declining recruitment density. Declining reproductive output (Koopman, Westgate, & Siders, ), recruit‐per‐egg ratios (Le Bris et al, ), and lipid‐rich prey of larvae (Carloni et al, ) have been proposed as mechanisms driving declines in recruitment density under warming conditions. Consequently, Le Bris et al () project that recruitment in a warming Gulf of Maine will show widespread declines across the American lobster's range with only slight increases projected for the northeastern Gulf of Maine.…”

“…Declining reproductive output (Koopman, Westgate, & Siders, ), recruit‐per‐egg ratios (Le Bris et al, ), and lipid‐rich prey of larvae (Carloni et al, ) have been proposed as mechanisms driving declines in recruitment density under warming conditions. Consequently, Le Bris et al () project that recruitment in a warming Gulf of Maine will show widespread declines across the American lobster's range with only slight increases projected for the northeastern Gulf of Maine. The assumption of reduced recruitment naturally leads to the conclusion that the Gulf of Maine lobster fishery is on the precipice of an imminent decline (Le Bris et al, ; Oppenheim, ).…”

“…Consequently, Le Bris et al () project that recruitment in a warming Gulf of Maine will show widespread declines across the American lobster's range with only slight increases projected for the northeastern Gulf of Maine. The assumption of reduced recruitment naturally leads to the conclusion that the Gulf of Maine lobster fishery is on the precipice of an imminent decline (Le Bris et al, ; Oppenheim, ). However, these alternative hypotheses may not fully capture patterns of lobster demography in the Gulf of Maine.…”

Scientific Considerations Informing Magnuson–Stevens Fishery Conservation and Management Act Reauthorization

“…Studies have demonstrated the value of fisheries management measures that preserve stock size and age structure, protect reproductive females and spawning congregations, and maintain abundance for enhancing the resilience of fish and invertebrate populations to climate impacts (Pershing et al 2015a;Le Bris et al 2018). As such, recognition that climate conditions can play a role in stock outcomes should not be viewed as an opportunity to relax the management standards established by the MSFCMA.…”