St Hubert Research Group

Seward, AK, United States

St Hubert Research Group

Seward, AK, United States
SEARCH FILTERS
Time filter
Source Type

Short J.W.,Glacier Consulting | Geiger H.J.,St Hubert Research Group | Haney J.C.,Terra Mar Applied science LLC | Voss C.M.,University of North Carolina at Chapel Hill | And 3 more authors.
Archives of Environmental Contamination and Toxicology | Year: 2017

Gulf menhaden (Brevoortia patronus) exhibited unprecedented juvenile recruitment in 2010 during the year of the Deepwater Horizon well blowout, exceeding the prior 39-year mean by more than four standard deviations near the Mississippi River. Abundance of that cohort remained exceptionally high for two subsequent years as recruits moved into older age classes. Such changes in this dominant forage fish population can be most parsimoniously explained as consequences of release from predation. Contact with crude oil induced high mortality of piscivorous seabirds, bottlenose dolphin (Tursiops truncatus), waders, and other fish-eating marsh birds, all of which are substantial consumers of Gulf menhaden. Diversions of fresh water from the Mississippi River to protect coastal marshes from oiling depressed salinities, impairing access to juvenile Gulf menhaden by aquatic predators that avoid low-salinity estuarine waters. These releases from predation led to an increase of Gulf menhaden biomass in 2011 to 2.4 million t, or more than twice the average biomass of 1.1 million t for the decade prior to 2010. Biomass increases of this magnitude in a major forage fish species suggest additional trophically linked effects at the population-, trophic-level and ecosystem scales, reflecting an heretofore little appreciated indirect effect that may be associated with major oil spills in highly productive marine waters. © 2017, The Author(s).


Haney J.C.,Terra Mar Applied science LLC | Geiger H.J.,St Hubert Research Group | Short J.W.,Glacier Consulting
Marine Ecology Progress Series | Year: 2015

Sackmann & Becker (2015; Mar Ecol Prog Ser 534:273-277, this volume) question assumptions we used to estimate bird mortalities from the 2010 Deepwater Horizon blowout in the northern Gulf of Mexico, recommending spill- and Gulf of Mexico-specific data, especially for estimating the probability of shoreline deposition of seabird carcasses killed at sea. The carcass drift and sinking study they recommend provides limited insight regarding shoreline deposition probability, because it fails to account for advection of tagged carcasses out to sea, the effects of tethering carcasses to buoyant floats, the time to abdominal cavity penetration by scavengers, or the very different conditions when the study was conducted in summer 2011 in comparison with the wind and current regime immediately following the blowout in spring 2010. Recognizing such limitations in studies of seabird carcass drift and sinking at sea, we think that the modeling approach we used, which provides parameter estimates primarily as uncertainty distributions rather than focusing on point estimates from single studies, more faithfully represents the state of knowledge supporting such estimates. © The authors 2015.


Haney J.C.,Terra Mar Applied science LLC | Geiger H.J.,St Hubert Research Group | Short J.W.,Glacier Consulting
Marine Ecology Progress Series | Year: 2014

Following the 2010 Deepwater Horizon MC 252 blowout in the Gulf of Mexico, most surface oil remained more than 40 km offshore, precluding reliable estimation of offshore avian mortality based on shoreline counts. Using an exposure probability model as an alternative approach, we estimated that between 36 000 to 670 000 birds died in the offshore Gulf of Mexico as result of exposure to oil from the Deepwater Horizon, with the most likely number near 200 000. Our exposure probability model is a technique for estimating this offshore component of avian mortality as the product of the oil slick area, the density of the birds above the oil slick, and the proportionate mortality of birds that could be exposed to oil during an assumed exposure period. The duration of the exposure period is treated as an estimated parameter to account for oil slick movement, exposure of birds immigrating to the oil-contaminated area, and re-exposure of birds that survived prior vulnerability to exposure. Total avian mortality is determined as the sum of mortalities from each exposure period. Exposure probability may be the only method available to estimate bird mortality from large, remote oil spills in the open ocean where carcasses are unlikely to ever reach shore. In the case of the Deepwater Horizon, the uncertainty interval is quite large because several parameters could not be well estimated. Historically sparse survey coverage effectively led to an under-appreciation of the effects of this spill on marine birds. © The authors 2014.


Haney J.C.,Terra Mar Applied science LLC | Geiger H.J.,St Hubert Research Group | Short J.W.,Glacier Consulting
Marine Ecology Progress Series | Year: 2014

Two separate approaches, a carcass sampling model and an exposure probability model, provided estimates of bird mortalities of 600 000 and 800 000, respectively, from the 2010 Deepwater Horizon MC 252 oil spill in coastal waters of the Gulf of Mexico. Monte Carlo simulation of parameter uncertainty led to respective 95% uncertainty intervals of 320 000 to 1200 000 and 160 000 to 1900 000. Carcass sampling relied on expansion factors multiplied by counts of bird carcasses retrieved in shoreline surveys, whereas exposure probability estimated bird deaths as a product of estimated coastal bird density, average oil slick size, slick duration, and proportionate mortality due to oiling. The low proportion of small-sized carcasses recovered, compared with considerably higher proportions of small live birds in coastal Gulf habitats, indicate an especially low probability of recovery for small birds after oil spills at sea. Most mortality affected 4 species: laughing gull Leucophaeus atricilla (32% of the northern Gulf of Mexico population killed), royal tern Thalasseus maximus (15%), northern gannet Morus bassanus (8%) and brown pelican Pelecanus occidentalis (12%). Declines in laughing gulls were confirmed by ∼60% reductions in National Audubon Society Christmas Bird Count data for 2010-2013 along the Gulf coast. Popu-lation-level effects in apex predators of this magnitude likely had effects on prey populations that warrant careful assessment. © The authors 2014.

Loading St Hubert Research Group collaborators
Loading St Hubert Research Group collaborators