Resilience of a Commercial Fishing Fleet Following Emergency Closures in the Gulf of Mexico

We used high-resolution fisheries-dependent data and a quantitative modeling approach to examine resilience of a commercial reef fish fleet after the Deepwater Horizon oil spill (DWH) emergency closures in 2010. Our results indicate that the fleet was largely resilient to the closures, although there were spatially-varying differences in attrition, and concomitant management changes and emergency payouts that likely influenced resilience. Five percent of previously active vessels exited the fleet after DWH (compared to the background annual attrition rate of ˜20%). The predicted probability of exiting after DWH was lower for vessels with a pre-closure history of high catch-per-unit-effort, low snapper revenue variability, or low grouper revenue. There was ˜80% overlap in pre- to post-DWH effort distribution, although vessels that exited concentrated effort in the north-central and eastern Gulf of Mexico. The Vessels of Opportunity program and other emergency compensation likely ameliorated some of the negative economic impacts from DWH, allowing more vessels to remain in the fleet than may have otherwise. Implementation of gear restrictions and individual fishing quotas leading up to DWH may have also ‘primed’ the fleet for resilience by removing marginal fishers. This work is novel in its use of high-resolution spatial data, coupled with trip logbooks, to construct quantitative models identifying drivers of fisher resilience after significant and sudden perturbations to fishery resources in the Gulf of Mexico. This work also highlights the need to better understand fisher response to disturbance for long-term fishery sustainability and management

Disturbance Modifies Payoffs in the Explore-exploit Trade-off

Decision-making agents face a fundamental trade-off between exploring new opportunities with risky outcomes versus exploiting familiar options with more certain but potentially suboptimal outcomes. Although mediation of this trade-off is essential to adaptive behavior and has for decades been assumed to modulate performance, the empirical consequences of human exploratory strategies are unknown beyond laboratory or theoretical settings. Leveraging 540,000 vessel position records from 2494 commercial fishing trips along with corresponding revenues, here we find that during undisturbed conditions, there was no relationship between exploration and performance, contrary to theoretical predictions. However, during a major disturbance event which closed the most-utilized fishing grounds, explorers benefited significantly from less-impacted revenues and were also more likely to continue fishing. We conclude that in stochastic natural systems characterized by non-stationary rewards, the role of exploration in buffering against disturbance may be greater than previously thought in humans. The empirical consequences of human explorative strategies are not fully understood. Here the authors find that during undisturbed conditions, more-explorative vessels gained no performance advantage while during a major disturbance event, explorers benefited significantly from less-impacted revenues and were also more likely to continue fishing

Disturbance Modifies Payoffs in the Explore-exploit Trade-off

Decision-making agents face a fundamental trade-off between exploring new opportunities with risky outcomes versus exploiting familiar options with more certain but potentially suboptimal outcomes. Although mediation of this trade-off is essential to adaptive behavior and has for decades been assumed to modulate performance, the empirical consequences of human exploratory strategies are unknown beyond laboratory or theoretical settings. Leveraging 540,000 vessel position records from 2494 commercial fishing trips along with corresponding revenues, here we find that during undisturbed conditions, there was no relationship between exploration and performance, contrary to theoretical predictions. However, during a major disturbance event which closed the most-utilized fishing grounds, explorers benefited significantly from less-impacted revenues and were also more likely to continue fishing. We conclude that in stochastic natural systems characterized by non-stationary rewards, the role of exploration in buffering against disturbance may be greater than previously thought in humans. The empirical consequences of human explorative strategies are not fully understood. Here the authors find that during undisturbed conditions, more-explorative vessels gained no performance advantage while during a major disturbance event, explorers benefited significantly from less-impacted revenues and were also more likely to continue fishing

Improving Detection of Short-duration Fishing Behaviour in Vessel Tracks by Feature Engineering of Training Data

Big data, such as vessel monitoring system (VMS) data, can provide valuable information on fishing behaviours. However, conventional methods of detecting behaviours in movement data are challenged when behaviours are briefer than signal resolution. We investigate options for improving detection accuracy for short-set fisheries using 581 648 position records from 181 vessels in the Gulf of Mexico bandit-reel fishery. We first investigate the effects of increasing VMS temporal resolution and find that detection accuracy improves with fishing-set duration. We then assess whether a feature engineering approach—in our case, changing the way pings are labelled when training a classifier—could improve detection accuracy. From a dataset of 12 184 observed sets, we find that the conventional point-labelling method results in only 49% of pings being correctly labelled as ‘fishing’, whereas a novel window-labelling method results in 88% of records being labelled as ‘fishing’. When the labelled data are used to train classifiers, point labelling attains true-positive/balanced-accuracy rates of only 37%/66%, whereas window labelling achieves 68%/83%. Finally, we map fishing distribution using the two methods, and show that point labelling underestimates the extent of fishing grounds by ∼33%, highlighting the benefits of window labelling in particular, and feature engineering approaches in general

Tracking the \u3cem\u3eHercules 265\u3c/em\u3e Marine Gas Well Blowout in the Gulf of Mexico

On 23 July 2013, a marine gas rig (Hercules 265) ignited in the northern Gulf of Mexico. The rig burned out of control for 2 days before being extinguished. We conducted a rapid‐response sampling campaign near Hercules 265 after the fire to ascertain if sediments and fishes were polluted above earlier baseline levels. A surface drifter study confirmed that surface ocean water flowed to the southeast of the Hercules site, while the atmospheric plume generated by the blowout was in eastward direction. Sediment cores were collected to the SE of the rig at a distance of ∼0.2, 8, and 18 km using a multicorer, and demersal fishes were collected from ∼0.2 to 8 km SE of the rig using a longline (508 hooks). Recently deposited sediments document that only high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) concentrations decreased with increasing distance from the rig suggesting higher pyrogenic inputs associated with the blowout. A similar trend was observed in the foraminifera Haynesina germanica, an indicator species of pollution. In red snapper bile, only HMW PAH metabolites increased in 2013 nearly double those from 2012. Both surface sediments and fish bile analyses suggest that, in the aftermath of the blowout, increased concentration of pyrogenically derived hydrocarbons was transported and deposited in the environment. This study further emphasizes the need for an ocean observing system and coordinated rapid‐response efforts from an array of scientific disciplines to effectively assess environmental impacts resulting from accidental releases of oil contaminants