Modeling the impacts of climate change on thorny skate (Amblyraja radiata) on the Northeast US shelf using trawl and longline surveys

Abstract

Climate change has been shown to impact marine fish populations and communities.With small population sizes, long reproduction times, and a rapidly warming habitat, thorny skate (Amblyraja radiata) could be particularly vulnerable. To examine this possibility, we used a two-stage generalized additive model to project future thorny skate abundances under two different climate scenarios. This is the first study in the northeastern United States to compare projections based on different survey methods (bottom trawl and longline), and results were heavily impacted by survey methodology. Models trained with the NOAA Bottom Trawl Survey projected a decrease in abundance of ~60%-80% in the Gulf of Maine and Georges Bank under the RCP 8.5 climate scenario. With aggressive mitigation (RCP 4.5), these decreases could be reduced to ~35%-45%. Models trained with a recent NOAA longline survey indicated that thorny skate abundance would be reduced 22% and 37% under business as usual and mitigation, respectively. There are substantial methodological differences between the two data sets, including capture technique and efficiency, total habitat coverage, and spatio-temporal coverage. This underscores the importance of continued, methodologically diverse surveys on the Northeast US continental shelf.Our results indicate that climate change will continue to negatively impact thorny skate populations by reducing the amount of thermally suitable habitat in the southern extent of their range. This information should be considered in future management decisions.

Mitogenomic evidence of population differentiation of thorny skate, Amblyraja radiata, in the North Atlantic

“…increasing abundance at more northerly latitudes (Kulka et al, 2020). This gradient of population trends is of significant interest to fishery managers and population biologists, particularly in relation to the evaluation of existing and future threats to A. radiata from fishing pressure and climate change (e.g., Grieve et al, 2021).…”

Spatio‐temporal dynamics of the common skate species complex: Evidence of increasing abundance

“…Further research is required in this area to gain a greater understanding of variations in annual recruitment levels and possible anthropogenic impacts. Moreover, climate change is predicted to impact skate populations in the future (Grieve et al, 2021). Bottom temperature showed low variable importance in the species distribution model.…”

Spatiotemporal joint species distribution modelling: A basis function approach

“…The dataset and links to archived R code for the application are provided in Appendix C, while additional details on the survey, which is publicly available, can be found at Northeast Fisheries Science Center (2021). We also refer to Morley et al (2018) and Grieve et al (2021) for recent examples of its usage. Briefly, the NOAA NEFSC fall bottom trawl survey is a long‐running survey (since 1963) that aims to monitor the spatiotemporal evolution of marine fish and invertebrates across the U.S. Northeast continental shelf (Northeast Fisheries Science Center, 2021).…”

“…We then fitted a CBFM where spatiotemporal basis functions were included in an additive manner (as described towards the beginning of Components of a CBFM), assuming a Bernoulli distribution and logit link function for the responses. As exploratory data analyses revealed clear evidence of non‐linear responses to covariates among many species (see also Grieve et al, 2021), we included smooth terms for each of the covariates through thin‐plate regression splines (Wood, 2017). For the spatial basis functions , we used 50 resolution adaptive thin‐plate splines constructed via the autoFRK package (Tzeng & Huang, 2018).…”