Showing papers by "Jonathan H. Grabowski published in 2019"

Chronic social disruption following a systemic fishery failure.

Abstract: In the United States, the iconic groundfish fishery for Gulf of Maine cod has endured several dramatic reductions in annual catch limits and been federally declared an economic disaster. Using a repeated cross-sectional survey of fishing captains to assess potential social impacts of the fishery failure, we found that psychological distress and social disruption were pervasive throughout New England fishing communities. For instance, our results indicate that 62% of captains self-reported severe or moderate psychological distress 1 y after the crisis began, and these patterns have persisted for 5 y. Using classification tree analyses, we found that low levels of trust in fisheries management was the most powerful predictor of both initial and chronic psychological distress. Distress was most severe among individuals without income diversity and those with dependents in the household. Compared to other aspects of fisheries, measuring and managing for noneconomic social outcomes and human well-being has lagged behind, even though it is a necessary component of mitigating the adverse impacts of fisheries disruptions.

Voluntary Restoration: Mitigation's Silent Partner in the Quest to Reverse Coastal Wetland Loss in the USA.

Abstract: Coastal ecosystems are under pressure from a vast array of anthropogenic stressors, including development and climate change, resulting in significant habitat losses globally Conservation policies are often implemented with the intent of reducing habitat loss. However, losses already incurred will require restoration if ecosystem functions and services are to be recovered. The United States has a long history of wetland loss and recognizes that averting loss requires a multi-pronged approach including mitigation for regulated activities and non-mitigation (voluntary herein) restoration. The 1989 "No Net Loss" (NNL) policy stated the Federal government's intent that losses of wetlands would be offset by at least as many gains of wetlands. However, coastal wetlands losses result from both regulated and non-regulated activities. We examined the effectiveness of Federally funded, voluntary restoration efforts in helping avert losses of coastal wetlands by assessing: (1) What are the current and past trends in coastal wetland change in the U.S.?; and (2) How much and where are voluntary restoration efforts occurring? First, we calculated palustrine and estuarine wetland change in U.S. coastal shoreline counties using data from NOAA's Coastal Change Analysis Program, which integrates both types of potential losses and gains. We then synthesized available data on Federally funded, voluntary restoration of coastal wetlands. We found that from 1996 to 2010, the U.S. lost 139,552 acres (~565 km2) of estuarine wetlands (2.5% of 1996 area) and 336,922 acres (~1,363 km2) of palustrine wetlands (1.4%). From 2006 to 2015, restoration of 145,442 acres (~589 km2) of estuarine wetlands and 154,772 acres (~626 km2) of palustrine wetlands occurred. Further, wetland losses and restoration were not always geographically aligned, resulting in local and regional "winners" and "losers." While these restoration efforts have been considerable, restoration and mitigation collectively have not been able to keep pace with wetland losses; thus, reversing this trend will likely require greater investment in coastal habitat conservation and restoration efforts. We further conclude that "area restored," the most prevalent metric used to assess progress, is inadequate, as it does not necessarily equate to restoration of functions. Assessing the effectiveness of wetland restoration not just in the U.S., but globally, will require allocation of sufficient funding for long-term monitoring of restored wetland functions, as well as implementation of standardized methods for monitoring data collection, synthesis, interpretation, and application.

Genetic diversity and phenotypic variation within hatchery-produced oyster cohorts predict size and success in the field

Abstract: The rapid growth of the aquaculture industry to meet global seafood demand offers both risks and opportunities for resource management and conservation. In particular, hatcheries hold promise for stock enhancement and restoration, yet cultivation practices may lead to enhanced variation between populations at the expense of variation within populations, with uncertain implications for performance and resilience. To date, few studies have assessed how production techniques impact genetic diversity and population structure, as well as resultant trait variation in and performance of cultivated offspring. We collaborated with a commercial hatchery to produce multiple cohorts of the eastern oyster (Crassostrea virginica) from field-collected broodstock using standard practices. We recorded key characteristics of the broodstock (male : female ratio, effective population size), quantified the genetic diversity of the resulting cohorts, and tested their trait variation and performance across multiple field sites and experimental conditions. Oyster cohorts produced under the same conditions in a single hatchery varied almost twofold in genetic diversity. In addition, cohort genetic diversity was a significant positive predictor of oyster performance traits, including initial size and survival in the field. Oyster cohorts produced in the hatchery had lower within-cohort genetic variation and higher among-cohort genetic structure than adults surveyed from the same source sites. These findings are consistent with "sweepstakes reproduction" in oysters, even when manually spawned. A readily measured characteristic of broodstock, the ratio of males to females, was positively correlated with within-cohort genetic diversity of the resulting offspring. Thus, this metric may offer a tractable way both to meet short-term production goals for seafood demand and to ensure the capacity of hatchery-produced stock to achieve conservation objectives, such as the recovery of self-sustaining wild populations.

A Waterfront View of Coastal Hazards: Contextualizing Relationships among Geographic Exposure, Shoreline Type, and Hazard Concerns among Coastal Residents

Abstract: Coastal communities exist on the front lines of diverse natural hazards and the growing impacts of climate change. While traditional strategies for dealing with coastal hazards have often involved the hardening or armoring of shorelines, more recent research and practice have demonstrated the value and cost-effectiveness of “living shorelines” and other ecosystem-based strategies for coastal protection. To explore potential relationships among geographic exposure (waterfront vs. inland), shoreline condition (armored vs. natural), and hazard concerns, we surveyed 583 waterfront and inland residents in the northern Gulf of Mexico. We found that overall concern for coastal hazards was similar across waterfront and inland residents, as well as among residents with both armored and natural shorelines. However, concern for specific hazards differed across these groups. Waterfront residents were significantly more concerned about major hurricanes and erosion than inland residents. Conversely, inland residents were more concerned with drought and flooding than waterfront residents. Among waterfront residents, specific hazard concerns were similar between residents with natural and armored shorelines with two key exceptions. Residents with armored shorelines reported higher concern for erosion and sea level rise than residents with natural shorelines. Our results suggest that armored shorelines do not necessarily alleviate concerns about coastal hazards. In the context of balancing social and ecological objectives in addressing coastal hazards or adapting to climate change, understanding the perceptions and behaviors of coastal residents is essential for conserving and protecting coastal ecosystems along residential shorelines.

Effects of Temperature and Ocean Acidification on the Extrapallial Fluid pH, Calcification Rate, and Condition Factor of the King Scallop Pecten maximus

Abstract: Increasing anthropogenic carbon dioxide is predicted to cause declines in ocean pH and calcium carbonate saturation state over the coming centuries, making it potentially harder for marine calcifiers to build their shells and skeletons. One mechanism of resilience to ocean acidification is an organism's ability to regulate pH and, thus, calcium carbonate saturation state, at its site of calcification. This mechanism has received detailed study in scleractinian corals but is relatively understudied in other taxonomic groups that are vulnerable to ocean acidification, such as bivalves. Here, the results of a 74-day controlled laboratory experiment investigating the impact of ocean acidification on the extrapallial fluid (EPF; the bivalve calcifying fluid) pH, calcification rate, and condition factor of the king scallop Pecten maximus at their average spring and summer temperatures (362 ppm/9.0°C, 454 ppm/12.3°C; 860 ppm/9.0°C, 946 ppm/12.3°C; 2,639 ppm/8.9°C, 2,750 ppm/12.1°C) are presented. Scallop EPF pH was lower than seawater pH in all treatments and declined with increasing pCO2 under the spring temperature (9°C) but was uncorrelated with pCO2 under the summer temperature (12°C). Furthermore, king scallop calcification rate and EPF pH were inversely correlated at 9°C and uncorrelated at 12°C. This inverse correlation between EPF pH and scallop calcification rate, combined with the observation that scallop EPF pH is consistently lower than seawater pH, suggests that pH regulation is not the sole mechanism by which scallops concentrate carbonate ions for calcification within their EPF. Calcification trends contrasted most other published studies on bivalves, increasing with ocean acidification under spring temperature and exhibiting no response to ocean acidification under summer temperature. Scallop condition factor exhibited no response to ocean acidification under spring temperature but increased with ocean acidification under summer temperature—exactly the opposite of their calcification response to ocean acidification. These results suggest that king scallops are relatively resilient to CO2-induced ocean acidification, but that their allocation of resources between tissue and shell production in response to this stressor varies seasonally.

Shifting perceptions of rapid temperature changes’ effects on marine fisheries, 1945–2017

Abstract: Global climate change has direct effects on marine fishes and in‐ vertebrates, including changes to migration patterns, distribution, and phenology, which consequently impacts their fisheries (Roessig, Woodley, Cech, & Hansen, 2004). The movement of marine animals poleward or to greater depths following optimal temperature con‐ ditions has been documented (Perry, Low, Ellis, & Reynolds, 2005; Pinsky, Worm, Fogarty, Sarmiento, & Levin, 2013), with global shifts at the leading range edges for marine species averaging 72 km per Received: 6 August 2018 | Revised: 1 July 2019 | Accepted: 15 July 2019 DOI: 10.1111/faf.12400

The relative importance of sub-populations to the Gulf of Maine stock of Atlantic cod

Abstract: Discriminating among sympatric sub-populations is critical not only for the investigation of fish population structure, but also for effective fishery management. The Gulf of Maine stock of Atlantic cod contains two genetically distinct sub-populations whose spawning grounds overlap in space, but not season. Lack of a practical tool for discriminating between these spring and winter spawners has thus far prevented addressing metapopulation structure in stock assessments and fishery management plans. To address this issue, we developed a simple approach to discriminate between the sympatric sub-populations that relies on internal otolith structures. Using a logistic regression model fit to training data (n = 577) and evaluated through cross-validation, we correctly classified individuals with 81% accuracy and predicted the overall sub-population mixture within 1%. Applying the model to a broader population dataset (n = 1642) revealed that spring-spawned cod are more concentrated within closed fishing areas and therefore experience a lower mortality rate. However, despite dominating older age classes and comprising a large fraction of the spawning stock, these spring cod contribute little to recruitment. This apparent sub-population difference in the stock–recruitment relationship has important consequences for assessment models and the success of management measures designed to rebuild the stock.

Invasion dynamics: interactions between the European Green Crab Carcinus maenas and the Asian Shore Crab Hemigrapsus sanguineus

Abstract: As ecosystems are increasingly inhabited by multiple invasive species, interactions among exotic species have the potential to negatively impact native communities and habitats, often in counterintuitive ways. In rocky intertidal habitats along southern New England, the recently introduced Asian Shore Crab, Hemigrapsus sanguineus, has been implicated in the displacement of the more established invasive European Green Crab, Carcinus maenas. We coupled faunal sampling with two field experiments to examine whether H. sanguineus is also displacing C. maenas in the Gulf of Maine. First, we investigated natural recruitment of the two species across an elevation gradient, using cage exclusion units to manipulate predator access. Excluding H. sanguineus adults significantly increased the density of C. maenas recruits, but not conspecific recruit density. Next, to simulate the transition that occurred from pre-invasion to the establishment of H. sanguineus, we conducted a predator inclusion experiment manipulating the density of adult H. sanguineus to examine the effects on C. maenas and conspecific recruit densities. In contrast to the previous experiment, we found that the density of H. sanguineus included in cages negatively affected conspecific recruit density but had no effect on C. maenas recruit density. We hypothesize that juxtaposing results from the two experiments may be a consequence of the considerably greater abundance of C. maenas recruits relative to H. sanguineus recruits during the first experiment. Our work highlights the importance of considering the multitude of factors that influence competitive and intraguild predation interactions, including density-dependent effects, ontogeny and life history characteristics.

Designing Effective Incentives to Reverse Coastal Habitat Degradation along Residential Shorelines

Abstract: Nature-based strategies for erosion control and coastal protection, such as “living shorelines”, are rapidly gaining traction among conservation scientists and practitioners. Living shorelines are often described as environmentally preferable alternatives to traditional shoreline armoring, which degrades natural coastal habitats and contributes to biodiversity loss in coastal ecosystems. However, a transition away from traditional armoring along many residential coastlines has been slow. We studied the attitudes, beliefs, and decisions of waterfront homeowners with natural vs. armored shorelines with a focus on identifying effective incentives for implementing living shorelines and reversing coastal habitat loss. We show that while only 18% of homeowners with vertical walls would willingly transition to a living shoreline, a modest economic incentive during a key window of opportunity could potentially persuade approximately 40% to reconsider. Our study demonstrates the critical importance of understanding the social, economic, and environmental influences on individual landowner decisions to develop effective strategies for coastal habitat conservation and restoration along private shorelines.