Hart
Deborah R.
Hart
Deborah R.
No Thumbnail Available
4 results
Search Results
Now showing
1 - 4 of 4
-
ArticleMarine reserve effects on fishery profits : a comment on White et al. (2008)(John Wiley & Sons, 2008-12-22) Hart, Deborah R. ; Sissenwine, Michael P.A recent study (White et al. 2008) claimed that fishery profits will often be higher with management that employs no-take marine reserves than conventional fisheries management alone. However, this conclusion was based on the erroneous assumption that all landed fish have equal value regardless of size, and questionable assumptions regarding density-dependence. Examination of an age-structured version of the White et al. (2008) model demonstrates that their results are not robust to these assumptions. Models with more realistic assumptions generally do not indicate increased fishery yield or profits from marine reserves except for overfished stocks.
-
ArticleProjected impacts of future climate change, ocean acidification, and management on the US Atlantic sea scallop (Placopecten magellanicus) fishery(Public Libary of Science, 2018-09-21) Rheuban, Jennie E. ; Doney, Scott C. ; Cooley, Sarah R. ; Hart, Deborah R.Ocean acidification has the potential to significantly impact both aquaculture and wild-caught mollusk fisheries around the world. In this work, we build upon a previously published integrated assessment model of the US Atlantic Sea Scallop (Placopecten magellanicus) fishery to determine the possible future of the fishery under a suite of climate, economic, biological, and management scenarios. We developed a 4x4x4x4 hypercube scenario framework that resulted in 256 possible combinations of future scenarios. The study highlights the potential impacts of ocean acidification and management for a subset of future climate scenarios, with a high CO2 emissions case (RCP8.5) and lower CO2 emissions and climate mitigation case (RCP4.5). Under RCP4.5 and the highest impact and management scenario, ocean acidification has the potential to reduce sea scallop biomass by approximately 13% by the end of century; however, the lesser impact scenarios cause very little change. Under RCP8.5, sea scallop biomass may decline by more than 50% by the end of century, leading to subsequent declines in industry landings and revenue. Management-set catch limits improve the outcomes of the fishery under both climate scenarios, and the addition of a 10% area closure increases future biomass by more than 25% under the highest ocean acidification impacts. However, increased management still does not stop the projected long-term decline of the fishery under ocean acidification scenarios. Given our incomplete understanding of acidification impacts on P. magellanicus, these declines, along with the high value of the industry, suggest population-level effects of acidification should be a clear research priority. Projections described in this manuscript illustrate both the potential impacts of ocean acidification under a business-as-usual and a moderately strong climate-policy scenario. We also illustrate the importance of fisheries management targets in improving the long-term outcome of the P. magellanicus fishery under potential global change.
-
ArticleAn integrated assessment model for helping the United States sea scallop (Placopecten magellanicus) fishery plan ahead for ocean acidification and warming(Public Library of Science, 2015-05-06) Cooley, Sarah R. ; Rheuban, Jennie E. ; Hart, Deborah R. ; Luu, Victoria ; Glover, David M. ; Hare, Jonathan A. ; Doney, Scott C.Ocean acidification, the progressive change in ocean chemistry caused by uptake of atmospheric CO2, is likely to affect some marine resources negatively, including shellfish. The Atlantic sea scallop (Placopecten magellanicus) supports one of the most economically important single-species commercial fisheries in the United States. Careful management appears to be the most powerful short-term factor affecting scallop populations, but in the coming decades scallops will be increasingly influenced by global environmental changes such as ocean warming and ocean acidification. In this paper, we describe an integrated assessment model (IAM) that numerically simulates oceanographic, population dynamic, and socioeconomic relationships for the U.S. commercial sea scallop fishery. Our primary goal is to enrich resource management deliberations by offering both short- and long-term insight into the system and generating detailed policy-relevant information about the relative effects of ocean acidification, temperature rise, fishing pressure, and socioeconomic factors on the fishery using a simplified model system. Starting with relationships and data used now for sea scallop fishery management, the model adds socioeconomic decision making based on static economic theory and includes ocean biogeochemical change resulting from CO2 emissions. The model skillfully reproduces scallop population dynamics, market dynamics, and seawater carbonate chemistry since 2000. It indicates sea scallop harvests could decline substantially by 2050 under RCP 8.5 CO2 emissions and current harvest rules, assuming that ocean acidification affects P. magellanicus by decreasing recruitment and slowing growth, and that ocean warming increases growth. Future work will explore different economic and management scenarios and test how potential impacts of ocean acidification on other scallop biological parameters may influence the social-ecological system. Future empirical work on the effect of ocean acidification on sea scallops is also needed.
-
ArticleEffects of warming and fishing on Atlantic sea scallop (Placopecten magellanicus) size structure in the Mid-Atlantic rotationally closed areas(Oxford University Press, 2023-04-17) Zang, Zhengchen ; Ji, Rubao ; Hart, Deborah R. ; Jin, Di ; Chen, Changsheng ; Liu, Yonggang ; Davis, Cabell S.The Atlantic sea scallop supports one of the most lucrative fisheries on the Northeast U.S. shelf. Understanding the interannual variability of sea scallop size structure and associated drivers is critically important for projecting the response of population dynamics to climate change and designing coherent fishery management strategies. In this study, we constructed time series of sea scallop size structures in three rotationally closed areas in the Mid-Atlantic Bight (MAB) and decomposed their total variances using the variance partitioning method. The results suggested that the interannual variances in sea scallop size structures were associated more with thermal stress in regions shallower than 60 m but more with fishing mortality in regions deeper than 60 m. The percentages of small (large) size groups increased (decreased) with elevated thermal stress and fishing pressure. We adopted a scope for growth model to build a mechanistic link between temperature and sea scallop size. Model results suggested a gradual decrease in maximum shell height and habitat contraction under warming. This study quantified the relative contributions of thermal stress and fishing mortality to the variance of scallop size structure and discussed the need for adaptive management plans to mitigate potential socioeconomic impacts caused by size structure changes.