Many people understand that killer whales should not be help captive in locations such as SeaWorld, based on the size of the animal relative to the size of the tank. Although, there are many other health issues that arise due to keeping these amazingly beautiful and intricate creatures in bath-tub sized tanks. In this blog, I wanted to discuss two of those issues: collapsed dorsal fin, and tooth decay.

The risk of infections and bacterium in pool-sized tanks due to tooth decay is a high concern for killer whales in captivity as they bite down on steel gates separating the training pools from the performance pools (Jett & Ventre, 2011). I will explain the consequences of tooth fragments and the exposure of the pulp of the teeth. Because the space in amusement parks is not comparable to the size of the ocean, there are elevated risks of diseases (Jett & Ventre, 2011). I have provided background information on health factors, diseases, visible signs of distress, and specific cases on the reasons scientists and societies began to focus on the captivity of orcas. Female orcas have a mean life expectancy of 50.2 years and a maximum of 80-90 years; wild males have a mean life expectancy of 29.2 years, and a maximum of 50-60 years (Olesiuk et al, 1990). Most industry sources insist around 35 years as the maximum captive lifespan (Mooney, 1998). Of the 107 orcas in captivity that have died since 1961, average length of survival was under six years. The health affects presented to orcas in captivity are of concern to medical, veterinary, and orca researchers. The elevated opportunities for infectious agents cause many problems for orcas in close proximities (Jett & Ventre, 2011). Treatments of these illnesses are constantly evolving as veterinary staff is discovering new diseases.

The factors that play into the deaths of orcas in captivity at young ages include: collapsed dorsal fin syndrome, tooth decay, and brain damage, to name the most studied (Ridgway 1979). Collapsed dorsal fin syndrome is a major theme in health concerns for captive orcas because it is not seen in the wild. This is due to the lack of space and movement that orcas are able to carry out in the pools they are held in. Contrary to captivity, the lateral, torsional, and compressive forces generated by consistent moving in the ocean water sculpt vertical dorsal fins (Jett & Ventre, 2011).  With the removal of these forces, and the constant surfacing of orcas in captivity, the connective tissue is impaired and results in a collapsed dorsal fin. This phenomenon is not seen in females due to the incomparable size of dorsal fins in females versus males. Male orcas acquire taller dorsal fins than females (Durdab et al, 2006). This also plays from the fact that orcas in captivity do not have to chase live fish due to a change in diet. Now, they eat dead, frozen fish, rather than having to strategize for their meals. This lack of movement causes fins to collapse, as well as provides less nutrition and other health affects.

 Killer whales are some of the most aggressive animals on the planet. Ways that they display dominance in cases of captivity include biting down on the steel bars of the pools. This is known as a process called “jaw-popping,” and is used to show another orca that they are of lower hierarchal status than the one showing aggression (Graham & Dow, 1990). In addition to showing aggression, it is very common for orcas to experience boredom and social strife, which is shown by chewing on the steel gates that separate them from their training pools and entertainment pools (Jett & Ventre, 2011). Tooth fragments are commonly found on the bottom of their pools and can leave some of the pulp of the tooth exposed if not picked up. Improper care of teeth can lead to a number of diseases including: valvular heart disease, gingivitis, pneumonia, stroke, and heart attack (Jett & Ventre, 2011). Pathogens have a direct route to the blood stream through open bore holes due to teeth falling out. These can then be deposited into the tissue of various organs throughout the body, such as the heart or kidney. Some orcas have their teeth drilled and are treated with prophylactic antibiotics to control the risk of bacteria. It is known that long-term antibiotic use can lead to health effects aside from tooth decay, such as antibiotic-resistant bacteria, increased susceptibility to certain cancers, and disruption of intestinal flora leading to phytochemical malnourishment (Jett & Ventre 2008). There is also an increase in risk for skin cancer since various antibiotics can cause photosensitiation and phototoxicity to those exposed to UVR. With the constant exposure to the sun, due to minimal availability of shade in the orca pools, the risk of skin cancer is higher in captivity than in the wild.