We all love bottlenose dolphins, but they are often referred to as the bullies of the ocean. They can be quite aggressive towards other cetaceans found off our coast, particularly harbour porpoises. Injuries caused by bottlenose dolphins can include teeth scrapes (known as rake marks), internal bruising, broken ribs, and hemorrhaging. This leads to both live and dead stranding but nearly always results in death. 

Read more here:  https://doi.org/10.1111/j.1748-7692.2011.00474.x  https://www.aquaticmammalsjournal.org/wp-content/uploads/2012/08/AM-38.3-Wilkin.pdf 

Leptospira is a spiral-shaped gram-negative bacteria that exists on many of the shores of California. This pathogen primarily affects California Sea Lions and causes their kidneys to stop functioning properly, limiting their ability to regulate fluids and filter toxins out of their body. In live animals, clinical signs include excessive water drinking, depressed demeanor, and most characteristically, folding their hind flippers under their abdomen. The animal can contract this disease from infected urine and being in close proximity to other infected animals. The 

Read more here: https://beaconbio.org/en/report/?reportid=3d5060a4-86c4-49bb-b3fa-c56de45ca3d6&eventid=bf6aec65-1743-4ea1-804a-289d3c6a5f66&pathogens=e31f7547-4a7a-4cc9-b643-dfcee95e831b 

https://www.sciencedirect.com/science/article/abs/pii/S0378113513000849?via%3Dihub 

https://link.springer.com/article/10.1186/1471-2334-7-125v 

Domoic Acid is a neurotoxin that acts as a glutomate receptor agonist in the heart and brain. Glutomate is a neurotransmitter that acts as an "on" signal for the central nervous system and when domoic acid binds to this receptor it over stimulate these cells and causes cell death leading to atrophy of particular organs. The primary organs that are affected are the hippocampal region of the brain and the heart muscles. Sea Lions contract this toxin through bioaccumulion by eating fish who have eaten the algae Pseudo-nitzschia. Clinical signs of this disease include seizures and cardiac arythmias. With warming ocean climates and increased fertalizer run-off, the California coast has become a hotspot for this disease. 

Read more here: 10.3389/fvets.2023.1245864 

For animals of all species, the begining of life is one of the hardest times for them. With fish moving farther offshore, even during their nursing months, recieving the proper nutrition is not a guarentee. After weaning, which happens abruptly in most of our species, pups and calfs are forced to learn how to find their nutirition themselves, often leading to stranding. With this year's super El Niño, we are already seeing a significantly increased case-load of adult animals with malnutrition. Unfortunately, we expect this to get worse through the end of 2026 and beginning of 2027, with pups that will now be struggling to find food and survive.  

It's worth remembering that malnutrition seems like a simple disease, but it is not. It can lead to electrolyte abnormalities and even digestive system cell death (blunting of brush boarder tips in the small intestine). These can lead to hear arythmias, neural changes, and a lack of ability to recover. 

After centuries of human ocean-navigation and fishing, fishing lines, ropes, packing straps, and hooks are littering the ocean. When these get entangeled around marine mammals or ingested, they are often unable to get themselves out of the entanglement. As the animal grows, this can cause lesions such a skin necrosis, severe injury musle and bone damage. If injested, foreign bodies can cause torsions of the gastrointestional tract and filling of the stomach with non-digestable material. 

Read more about California's initiatives to decrease entanglements here: https://wildlife.ca.gov/News/Archive/cdfw-protects-returning-humpback-whales-from-entanglement-risk-while-providing-continued-fishing-opportunities-for-dungeness-crab 

And new NOAA regulation about crab pot lines: https://www.fisheries.noaa.gov/feature-story/new-noaa-rule-helps-fishing-crews-reduce-whale-entanglements-and-save-time