By QUINTON SMITH/YachatsNews.com
Jim Rice gets lots of questions about seals and sea lions.
Most inquiries are about their health or when adult or offspring come ashore.
Rice is the sole employee of the Oregon Marine Mammal Stranding Network at the OSU Marine Mammal Institute in Newport. His job now is to report on – with the help of a network of volunteers – when sea lions, seals other marine mammals come onshore dead or alive.
Rice and his volunteers no longer rescue mammals — they let nature take its course — but use information to glean insight into the health of sea life. Information they gather goes into a large, national data base operated by the National Oceanic and Atmospheric Administration.
Rice agreed to do a question-and-answer session with YachatsNews.com on California sea lions and their seasonal sighting close to local beaches.
Question: People in the Yachats area are seeing sea lion “rafts” close to shore this spring. Can you explain what they are — and are not?
Answer: Sea lions often appear in large groups on the water’s surface displaying a behavior commonly known as “rafting.” This is as an alternative to hauling out on shore to get rest. Rafting sea lions are often mistaken for being dead or entangled. Although they may appear to be in distress, this is normal behavior and is no cause for alarm.
Q: Are these California sea lions or Stellars? Where do they come from, or where are they heading?
A: They are likely California sea lions (it’s possible Stellers do it as well, although I’ve only seen or read about it with California sea lions), which live and forage in the waters of the Pacific Northwest during the fall, winter and spring months. They aren’t necessarily going or coming from anywhere in particular when they are observed rafting; they may just be attracted to a particular area due to an abundance of prey.
Q: The rafting seems to occur during the spring? Is that correct, or is it a year-round phenomenon?
A: It does seem to be reported more commonly in the spring, but it can happen year-round. We see it happen in Yaquina Bay in Newport frequently in December and January when there is a large influx of sea lions and haul out space is at a premium. Reports of rafting does increase as the we get later into May and early June, as the sea lions are migrating south to the Channel Islands of southern California to meet up with females and breed.
Q: Many of the sea lions seem to hold a flipper in the air. What is that for?
A: It is thought that they do it to help regulate their body temperature, allowing the flipper to warm or cool their blood as it circulates through the flipper in the air. I suspect it may also help them to balance their bodies, as the opposite flipper may be held outstretched underwater as well, acting as a keel to keep them stable in the water.
Q: Is the “rafting” also a sea lion defensive measure to protect from predators like orcas?
A: Certainly group behaviors like rafting can offer sea lions an aspect of safety in numbers, as some members will undoubtedly be more alert than others at any given time and can provide some vigilance to the threats of approaching predators while others are able to more fully rest while at sea.
Q: Speaking of which, are there orcas off the Oregon coast this time of year looking for prey like sea lions and/or gray whales?
A: Yes – spring is the time of year we most commonly have sightings of orcas, or killer whales, along the Oregon coast. They are known to swim into rivers and bays in search of seals and sea lions and prey upon migrating gray whales along the ocean shore.
Q: What’s the population status of California sea lions on the Oregon coast?
A: California sea lions comprise a single population along the entire West Coast, estimated at approximately 300,000. It grew considerably over the last few decades but is relatively stable now.
Q: People see the sea lions hauled up on the docks in the Newport bayfront almost year-round. Can you tell us more about the migration patterns from the Oregon coast to the south or north?
A: Male California sea lions reside in Oregon waters for most of the year, but are largely absent between late June and early August while they are in southern California waters to breed. Only a few juveniles and adult stragglers remain in Oregon. The vast majority of female California sea lions remain in California waters year-round.
Q: We see a lot of harbor seals in Alsea Bay (there’s an estimated 600). Do harbor seals spend much time in the ocean, or are they pretty much as their name implies?
A: Harbor seals range all along the Oregon coast, often foraging many miles offshore, as well as in harbors and bays, and utilize haul out areas at river mouths, sand spits, rocky coves.
Q: Anything else about harbor seals?
A: Spring is harbor seal pupping season, a time of year when people often find newborn seals alone on the beach and assume they have been abandoned by their mothers and feel a need to do something to help them. Unfortunately, acting on those intentions can be detrimental to a pup’s survival. It is normal for pups to rest on shore unattended while their mothers remain in the water, foraging for food and only returning to the pup periodically to nurse it. If people interfere with this process, either by moving the pup or simply creating a disturbance by getting close to it and preventing the mother from coming ashore, the mother might stop caring for the pup. We ask people to please give pups lots of space (50 to 100 yards) and not interfere with this natural process.
Disease and Parasitism. California sea lions are susceptible to gastric disorders, viral, and bacterial infections. Leptospirosis is a type of bacterial infection commonly found in California sea lions. Leptospirosis primarily attacks the kidneys and can lead to permanent kidney damage, kidney failure, and even death.
Dogs can become infected and develop leptospirosis if their mucous membranes (or skin with any wound, such as a cut or scrape) come into contact with infected urine, urine-contaminated soil, water, food or bedding; through a bite from an infected animal; by eating infected tissues or carcasses.
People also get it. Leptospirosis may occur in two phases: After the first phase (with fever, chills, headache, muscle aches, vomiting, or diarrhea) the patient may recover for a time but become ill again. If a second phase occurs, it is more severe; the person may have kidney or liver failure or meningitis.
When a dead sea lion was on the beach below the viewing platform and another in the bay for a while they posted signs for people and dogs to stay at least 50-100 feet away due to Leptospirosis.