Changes in higher trophic level productivity, diversity and niche space in a rapidly warming continental shelf ecosystem

Friedland, Kevin D.; Langan, Joseph A.; Large, Scott I.; Selden, Rebecca L.; Link, Jason S.; Watson, Reg; Collie, Jeremy S.

doi:10.1016/j.scitotenv.2019.135270

Cited by 58 publications

(60 citation statements)

References 79 publications

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“…This study is based on a series of SDMs, created with RF models, for dominant species in the U.S. Northeast Shelf (Friedland et al., 2020). Details for sources of variables in this study are provided in the respective sections below.…”

Section: Methodsmentioning

confidence: 99%

Dynamic changes in American lobster suitable habitat distribution on the Northeast U.S. Shelf linked to oceanographic conditions

Mazur

Friedland

McManus

et al. 2020

Fisheries Oceanography

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American lobster (Homarus americanus) supports one of the most valuable regional fisheries in the United States, with its abundance and distribution profoundly influenced by environmental conditions. To explain how lobster distribution has changed over time and assess the role of environmental variables on these changes, we used random forest classification and regression tree models to estimate occupancy and biomass in two seasonal periods. The occupancy models were fit to static and dynamic variables, which yielded model fits with AUC scores of 0.80 and 0.78 for spring and fall, respectively. Biomass models were fit with the same data and resulted in models explaining 61% and 63% of the spring and fall biomass variance, respectively. Significant variables scored in the formation of the regression trees were secondary productivity (i.e., zooplankton), bathymetry characteristics, and temperature. American lobster suitable habitat has changed regionally; habitat has increased in the Gulf of Maine and declined in Southern New England. There is also evidence of declining habitat along the inshore margin of the Gulf of Maine, which has been accompanied by a shift in occupancy probability offshore. Habitat suitability results from the random forest models provide insights on the structure and function of lobster habitat and context to understand recent population trends.

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Section: Methodsmentioning

confidence: 99%

Dynamic changes in American lobster suitable habitat distribution on the Northeast U.S. Shelf linked to oceanographic conditions

Mazur

Friedland

McManus

et al. 2020

Fisheries Oceanography

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“…These changes will alter regional food-web structure and species composition. On the other hand, an influx of warm-water species from the south may have increased marine diversity and productivity within some regions of the US northeast in recent decades (Friedland et al 2020).…”

Section: Projected Changes In the Nafo Convention Areamentioning

confidence: 99%

Climate-change impacts and fisheries management challenges in the North Atlantic Ocean

Bryndum-Buchholz

Boyce

Tittensor

et al. 2020

Mar. Ecol. Prog. Ser.

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Climate-induced changes in the world’s oceans will have implications for fisheries productivity and management. Using a model ensemble from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP), we analyzed future trajectories of climate-change impacts on marine animal biomass and associated environmental drivers across the North Atlantic Ocean and within the Northwest Atlantic Fisheries Organization (NAFO) convention area and evaluated potential consequences for fisheries productivity and management. Our ensemble results showed that the magnitude of projected biomass changes increased over time and from a low (RCP2.6) to high (RCP8.5) emissions scenario. Within individual NAFO divisions, however, projected biomass changes differed in the magnitude and sometimes direction of change between near (the 2030s) and far future (the 2090s) and contrasting emissions scenarios. By the 2090s, most NAFO divisions with historically (1990-1999) high fisheries landings were projected to experience biomass decreases of 5-40%, while Arctic and subarctic divisions with lower historical landings were projected to experience biomass increases between 20 and 70% under RCP8.5. Future trajectories of sea surface temperature and primary production corroborated that the far-future, high-emissions scenario poses the greatest risk to marine ecosystems and the greatest challenges to fisheries management. Our study summarizes future trends of marine animal biomass and underlying uncertainties related to model projections under contrasting climate-change scenarios. Understanding such climate-change impacts on marine ecosystems is imperative for ensuring that marine fisheries remain productive and sustainable in a changing ocean.

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“…It is difficult to predict the specific ecological response to any change in habitat (Friedland et al, 2020) due to the complexity of interactions and pressures in the region. Our observations indicate that there is an expansion of fish biomass in the NES, but at the same time, growth is slowing for many species.…”

Section: Discussionmentioning

confidence: 99%

“…Seasonal time series trends in biota were represented by the CPUE for biomass of all taxa from the bottom trawl survey (see "Data Availability Statement"), and by assignment to functional groups based on their adult prey preferences and vertical distribution (Friedland et al, 2020). The functional groupings included benthivores, demersal piscivores, pelagic piscivores, and planktivores.…”

Section: Survey Biomass By Functional Groupsmentioning

confidence: 99%

“…Fish and macroinvertebrate species have undergone significant shifts in their distribution (Friedland et al, 2019), which is already impacting human populations (Rogers et al, 2019). Rising temperatures appears to have increased the available occupancy habitat for most species and concomitant with this expansion of habitat, there has been an increase in upper trophic level biomass across a range of functional groups (Friedland et al, 2020). The principal multi-species fisheries in the region were greatly reduced by over-fishing in the 1990s, and much of the economic space is now occupied by single species fisheries on invertebrate taxa (Goode et al, 2019;Wiedenmann and Jensen, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Changing Physical Conditions and Lower and Upper Trophic Level Responses on the US Northeast Shelf

et al. 2020

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Sea surface temperature (SST), salinity, and chlorophyll concentration (CHL) have changed in the US Northeast Shelf ecosystem over recent decades. The changes in these parameters were distinctly marked by change points around the year 2012 resulting in a 0.83 • C increase in SST, a 0.3 PSU increase in salinity, and decrease in CHL in excess of 0.4 mg m −3. Where temperature and salinity shifted in mean level around their respective change points, CHL declined in a more monotonic fashion. Modeled data suggest that the shift in CHL resulted in a greater contribution of picoand nanophytoplankton and a decreased contribution of microphytoplankton to overall CHL. Complementary estimates of the contribution of different phytoplankton functional types suggest a diminished contribution of diatoms to the phytoplankton community. Hence, not only is there evidence of a decline in the overall primary production capacity of the ecosystem, but also evidence of a fundamental change in the size and quality of phytoplankton supporting food webs. Two ecosystem responses to the observed changes in SST, salinity, and CHL were analyzed. Both length and weight at age have declined for a number of species, and both measures of growth appear to be negatively associated with temperature and positively associated with CHL. Biomass of fish and macroinvertebrates has declined in recent years, with a decrease in pelagic species associated with a decrease in CHL, while the decline in demersal species was associated with an increase in temperature. Collectively, these ecosystem changes appear to be the result of the complex interactions of both thermal effects and changes at the base of the food web.

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Changes in higher trophic level productivity, diversity and niche space in a rapidly warming continental shelf ecosystem

Cited by 58 publications

References 79 publications

Dynamic changes in American lobster suitable habitat distribution on the Northeast U.S. Shelf linked to oceanographic conditions

Dynamic changes in American lobster suitable habitat distribution on the Northeast U.S. Shelf linked to oceanographic conditions

Climate-change impacts and fisheries management challenges in the North Atlantic Ocean

Changing Physical Conditions and Lower and Upper Trophic Level Responses on the US Northeast Shelf

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