Current studies show that the lingering oil is no longer bioavailable and key injured resources are no longer being affected by the lingering oil.
Injured populations met the recovery criteria established by the EVOS Trustee Council for sea otters (between 2009 and 2014, 20 to 25 years post-Spill) and harlequin ducks (by 2013, 24 years post-Spill) (Ballachey et al., 2014; Esler 2015). Recovery, as defined by the EVOS Trustee Council, generally requires a return to conditions that would have been present had the Spill not occurred, as well as cessation of exposure of animals to oil lingering since the Spill. Lacking pre-Spill baseline studies, researchers contrasted a number of metrics between oiled and unoiled areas, including abundance, survival, habitat use, physiology, biomarkers of oil exposure, and population trajectories based on models.
A 2013 NOAA report assessed contamination in fish and shellfish the Chugach and Cook Inlet Native communities of Nanwalek, Port Graham and Seldovia, located at the southwestern tip of the Kenai Peninsula near the entrance to Kachemak Bay, an embayment off the lower Cook Inlet. In these villages, subsistence activities are a large part of the traditional culture, as well as a means of providing protein for Tribal members. This study found that the fish and shellfish sampled showed low tissue contamination, and pathologic effects of the parasites and diseases were absent or minimal. Taken together, the results showed that the fish and shellfish were healthy and pose no safety concern for consumption. The full NOAA report can be found here: https://docs.lib.noaa.gov/noaa_documents/NOS/NCCOS/TM_NOS_NCCOS/nos_nccos_173.pdf
The 2013 NOAA report found that subsistence food items can be a health concern in rural Alaska because community members often rely on fish and wildlife resources not routinely monitored for persistent bioaccumulative contaminants and pathogens. Subsistence activities are a large part of the traditional culture, as well as a means of providing protein in the diets for Tribal members. In response to the growing concerns among Native communities, contaminant body burden and histopathological condition of chum and sockeye salmon (Oncorhynchus keta and Oncorhynchus nerka) and the shellfish cockles and softshell clams (Clinocardium nuttallii and Mya arenaria) were assessed. In the Spring of 2010, the fish and shellfish were collected from traditional subsistence harvest areas in the vicinity of Nanwalek, Port Graham, and Seldovia, AK, and were analyzed for trace metals and residues of organic contaminants routinely monitored by the NOAA National Status & Trends Program (NS&T). Additionally, the fish and shellfish were histologically characterized for the presence, prevalence and severity of tissue pathology, disease, and parasite infection. The fish and shellfish sampled showed low tissue contamination, and pathologic effects of the parasites and diseases were absent or minimal. Taken together, the results showed that the fish and shellfish were healthy and pose no safety concern for consumption. This study provides reliable chemistry and histopathology information for local resource managers and Alaska Native people regarding subsistence fish and shellfish use and management needs.
The Council conducted surveys in 2004 and 2014 to determine the status of subsistence use of fish and wildlife in Exxon Valdez-affected area communities. The 2014 update, James A. Fall and Garrett Zimpelman, editors, Update on the Status of Subsistence Uses in Exxon Valdez Oil Spill Area Communities, 2014, surveys the subsistence use of fish and wildlife in the communities affected by the Exxon Valdez oil spill. An executive summary is found at: http://evostc.state.ak.us/Universal/Documents/Publications/15150122ExecutiveSummary.pdf and the 400- page final report is at: http://evostc.state.ak.us/Store/FinalReports/2015-15150122-Final.pdf. Excerpted from the 2014 Update at page 333:
Evidence from the 2003 study that subsistence uses were recovering based on food safety issues included improved confidence in the safety of eating chitons, Pacific herring, and harbor seals. However, confidence in eating clams remained low, and some respondents suspected that increasing incidents of PSP were related to conditions created by the oil spill (Fall 2006 at pg. 394).
Based on the findings from the 2014 survey, evidence that subsistence uses are recovering based on food safety issues includes the following:
Potential evidence that subsistence uses are not fully recovered based on this criterion includes the following
In summary, while a suspicion of EVOS-caused food safety issues remains among a small segment of the study communities’ populations, a strong majority expressed confidence in subsistence food safety and this confidence has continued to grow. Nevertheless, community residents are aware of pockets of residual oil within their traditional use area. Respondents also expressed broader concerns about potential food safety issues, such as radiation contamination on fish from the Fukushima Daiichi nuclear accident in Japan and the effects of warming ocean temperatures on bivalves.
The 2014 Subsistence Update further discusses the difficulties of assessing various effects on subsistence. The 2014 Update notes that assessing the recovery of subsistence uses also includes the difficult task of separating the potential lingering effects of the oil spill from other concurrent environmental, economic, social, and cultural factors. The study found potential evidence of a lack of a full recovery from EVOS effects but noted it is likely not solely related to EVOS and some changes might not be connected to EVOS conditions at all.
As explanations for lower harvests and uses, respondents cited personal reasons, work commitments, and general lower levels of effort as often, or more often, than natural resource conditions, and few directly cited spill effects as a single or primary cause of changing subsistence patterns. For example, respondents in Chenega Bay, Cordova, and Tatitlek linked heavy snowfalls that reduced deer populations to lower deer harvests. Respondents in Nanwalek and Port Graham attributed lower subsistence Pacific halibut harvests to increased pressure from sport fishing charter operations; and in Chenega Bay and Nanwalek, respondents discussed competition between subsistence salmon fisheries and commercial fisheries. Nanwalek residents are concerned about the effects of erosion on the sockeye salmon stocks of the English Bay River, which they attribute to both climate change and road and trail development. Rising costs of equipment and fuel inhibit or limit harvest effort in all the study communities. A drop in involvement in commercial fisheries in several communities has also affected access to harvest areas and equipment as well as a source of cash income linked to local resources. Respondents in Nanwalek and Port Graham discussed an overall decline in populations of marine invertebrates that they attributed to a variety of factors, including commercial overharvests, sea otter predation, local overharvests, water pollution, and warming water temperatures. See Fall and Zimpelman (2014) Update at page 333. For more information see: http://evostc.state.ak.us/Store/FinalReports/2015-15150122-Final.pdf