Evidence of Anthropogenic Trauma in Marine Mammals Stranded Along the Central California Coast

Evidence of Anthropogenic Trauma in Marine Mammals Stranded Along the Central California Coast

Entanglement
Ocean trash

Abstract

A total of 11,162 stranded marine mammals was admitted to a rehabilitation center on the central California coast between January 2003 and September 2015. Six hundred seventeen animals (6%) had evidence of anthropogenic trauma (AT). California sea lions comprised the majority (83%) of AT cases, particularly by entanglement in marine debris (n = 277) and gunshot injuries (n = 165). Guadalupe fur seals had the highest prevalence of entanglement in marine debris. Cetaceans were primarily affected by boat collisions (n = 19). The highest numbers of overall strandings were recorded in 2009 (n = 1,690) and 2015 (n = 1,666); 2009 also had the highest total number (n = 137) and prevalence (8%) of AT cases. Prevalence of fishing tackle cases increased compared to similar data from 1986 to 1998 while prevalence of gunshot cases decreased, and other causes remained static. Cases of fisheries interactions were further examined and characterized, and when direct fisheries interactions were separated from other causes of AT, fisheries interactions accounted for 50% (n = 310) of all AT cases during the study period. Direct fisheries interactions were the most common type of AT observed among stranded marine mammals in central California. Tracking AT trends is important to further understand possible causes and inform mitigation efforts.

Barcenas de la Cruz, D. , 2017. Evidence of anthropogenic trauma in marine mammals stranded along the central California coast, 2003–2015 Marine Mammal Science DOI: 10.1111/mms.12457.

Read the full research paper

Related Publications

See All Publications

{"image":"\/Animals\/Patients\/California sea lions\/2015\/cropped-images\/csl-thin-mint-photo-c-kelsey-bickert-286-230-1869-1460-1666302738.jpg","alt":"California sea lion with entanglement","title":"Use of Acoustic Transmitter-Equipped Remote Sedation to Aid in Entangled Sea Lion Response","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/use-of-acoustic-transmitter-equipped-remote-sedation-to-aid-in-entangled-sea-lion-response","label":"Research Paper"}

Research Paper

Use of Acoustic Transmitter-Equipped Remote Sedation to Aid in Entangled Sea Lion Response

{"image":"\/Animals\/Wild\/California sea lion\/cropped-images\/wild-sea-lion-with-entanglement-scar-shutterstock-1338-335-4110-3210-1695081803.jpg","alt":"wild California sea lion with entanglement scar","title":"Disentanglement and Multi-Year Survival of a California Sea Lion with an Upper Airway Stoma Due to Entanglement","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/disentanglement-and-multi-year-survival-of-a-california-sea-lion-with-an-upper-airway-stoma-due-to-entanglement","label":"Research Paper"}

Research Paper

Disentanglement and Multi-Year Survival of a California Sea Lion with an Upper Airway Stoma Due to Entanglement

{"image":"\/Animals\/Patients\/Sea otters\/2025\/cropped-images\/so-mooring-release-2-laurie-miller-c-the-marine-mammal-center-USFWS-permit-MA101713-1-80-0-1270-992-1757003194.jpg","alt":"A southern sea otter rests in the ocean after being released from rehabilitative care.","title":"Entangled in Ocean Trash, Sea Otter Mooring Gets a Second Chance at Life","link_url":"https:\/\/www.marinemammalcenter.org\/news\/entangled-in-ocean-trash-sea-otter-mooring-gets-a-second-chance-at-life","label":"Patient Update","date":"2025-09-05 02:00:00"}

Patient Update

Entangled in Ocean Trash, Sea Otter Mooring Gets a Second Chance at Life

September 5, 2025

{"image":"\/Animals\/Patients\/California sea lions\/2024\/cropped-images\/csl-pinger-entanglement-photo-by-bill-hunnewell-c-the-marine-mammal-center-119-0-1270-992-1740529371.jpg","alt":"An entangled California sea lion with a netting material around its neck. ","title":"What it Takes to Rescue an Entangled Sea Lion","link_url":"https:\/\/www.marinemammalcenter.org\/news\/what-it-takes-to-rescue-an-entangled-sea-lion","label":"News Update","date":"2025-02-27 02:00:00"}

News Update

What it Takes to Rescue an Entangled Sea Lion

February 27, 2025

{"image":"\/Animals\/Wild\/Harbor seal\/cropped-images\/01-hslucinda2934releasephoto-by-john-beltran-c-the-marine-mammal-center-16-0-0-1270-992-1734387848.jpg","alt":"A Pacific harbor seal moves into the ocean.","title":"From Rescue to Release: Marine Mammal Patients Seen Thriving in the Wild","link_url":"https:\/\/www.marinemammalcenter.org\/news\/from-rescue-to-release-marine-mammal-patients-seen-thriving-in-the-wild","label":"Patient Update","date":"2024-12-17 12:06:08"}

Patient Update

From Rescue to Release: Marine Mammal Patients Seen Thriving in the Wild

December 17, 2024

{"image":"\/Animals\/Wild\/Elephant seal\/1-es-liddie-disentangledphoto-by-heather-harris-c-the-marine-mammal-centernoaa-permit-24359.jpg","alt":"A sedated northern elephant seal on the beach with a wound on its neck.","title":"Life-Saving Disentanglement Frees Northern Elephant Seal Liddie from Ocean Trash","link_url":"https:\/\/www.marinemammalcenter.org\/news\/life-saving-disentanglement-frees-northern-elephant-seal-liddie-from-ocean-trash","label":"Patient Update","date":"2024-12-06 13:43:00"}

Patient Update

Life-Saving Disentanglement Frees Northern Elephant Seal Liddie from Ocean Trash

December 6, 2024