Unalaska, AK – The population of the endangered western stock of Steller Sea Lions seems to be stabilizing overall. Sea lion population data presented this week to the North Pacific Fishery Management Council's Groundfish Management Team showed that the pup numbers increased by an average of one percent per year since 1998. However, Alaska Fisheries Science Center director Doug DeMaster said that number is smaller than it should be and is not statistically significant.

"That's a pretty small rate of increase. This is a population that should be doing five to eight percent year if it was recovering at its maximum rate. So one percent per year that's better than declining. But it's not a statistically significant rate of increase," he said. "So we would have to say that since the late 1990s there's been no significant trend in abundance. It's stable. But at least it doesn't appear to be declining."

The numbers work out to be about eight more pups per rookery per year in the western stock. Combining this information with other data, that translates to two more females per year survive to breeding age in each of the 31 rookeries. Sea lion biologist Lowell Fritz said that's better than no increase but the population certainly isn't out of the woods yet, especially when you look at the different sub-regions. DeMaster agrees.

"We're very concerned that the different areas are responding differently. In particular, that Western Aleutian area appears not to be recovering," he said.

In the central part of the Steller Sea Lion range, near Unalaska and the western part of the Gulf of Alaska, the population grew at about 3 to 4 percent per year from 2005 to 2009. Near Kodiak it was more like 2 percent. Fritz said the population in the far western region is declining at about ten percent per year and one rookery is on the verge of extinction.

DeMaster said no one knows why the western sub-region population is still declining. Unlike other sea lion groups, their major food source is Atka mackerel, which is commercially fished, but it is not known if this is related to the decline. Other populations feed on pollock, which is also fished. It is unknown what caused the overall species decline as well in the late 70s, but some data points to problems with reproduction.

"For some reason reproduction in these Stellars appears to be 30, 40, 50 percent lower than we would expect."

The National Marine Fisheries Service will need to determine whether or not the federally managed commercial fisheries are negatively impacting the Steller Sea Lion populations and if so, what to do about it. Currently, boats are restricted from fishing ten miles from most rookeries and haul-outs and 20 miles from others.

In March, NMFS will review a draft biological opinion on the status of the western population of Steller Sea Lions and decide if further restrictions are needed.

The eastern population of Steller Sea Lions, which stretches from southeast Alaska to California, is increasing at about five percent per year, or an average of 98 more pups per year for each of Southeast's five rookeries.