Pandemic hit sea lion, penguin research hard
The ‘‘pandemic gap’’ is starting to show up in datasets and research studies. These statistical holes were expected after researchers weren’t able to get into the field to collect data because of Covid-19 and various lockdowns and restrictions brought on by the pandemic.
For example, sea lion researchers from the Department of Conservation were unable to visit the subantarctic islands last season.
They managed a brief visit this season but didn’t accomplish all the data collection and other work they hoped. A budget squeeze and boat availability were also partially responsible.
Further, the researchers visited the islands earlier in the season than they wished, meaning all the sea lions pups hadn’t yet been born. They had to ‘‘adjust’’ the numbers, based on counts from previous years.
These troubles introduced uncertainty into the population counts for New Zealand sea lions, or rā poka.
They are listed as ‘‘nationally vulnerable’’ in the country’s threat classification system, meaning they face a ‘‘high risk of extinction in the medium term’’.
The data collected showed 1759 pups were born on the Auckland Islands this season. Alternatively, using different counting and statistical methods, 1617 pups were born.
Either way, the numbers were above the minimum target of 1575 pups set by the Sea Lion Threat Management Plan agreed to by DOC and MPI in 2017.
While the five-year objective to ‘‘halt the decline’’ of the New Zealand sea lion has been achieved, further in-depth counting was required to prevent a ‘‘significant data deficiency, which will limit our ability to analyse demographic trends and effectiveness of interventions,’’ wrote Mel Young and Kat Manno in a recently published DOC field research report.
Antarctica NZ experienced similar disruptions. There was no Adelie penguin census on Ross Island in 2020-21, the first gap in this record in 40 years, departing chief scientific adviser John Cottle said. Counts at colonies more distant from Scott Base were less regular.
‘‘Long-term trends are important in this dataset and a single year, while preventing some analyses, won’t negate those long-term trend assessments,’’ Cottle said.
There was no fieldwork in the McMurdo Dry Valleys in 2020-21, and it was limited in the season just ended. This research investigates how microbial communities in lakes are responding to rising water levels fed by the melting glaciers.
‘‘The main loss of data was in . . . the colonisation sequence of the newly flooded areas around the lake, but the reduced season in 2021-22 was able to undertake this,’’ Cottle said. ‘‘A two-year sampling interval is almost as valuable as an annual sampling.’’
It wasn’t just counting that was disrupted by the pandemic. Back on the subantarctics, research into Ivermectin treatment for sea lion pups was also put off. Ivermectin is the same drug trumped by some as a treatment for Covid19, but not by Medsafe.
Sea lion pups on the Auckland Islands often die from a disease called Klebsiella pneumoniae. It’s a bacterial infection, and Ivermectin treats parasitic worms, so it is something of a mystery why the drug helps sea lion pups, said Laura Boren, a science adviser at DOC.
They hoped to test a theory that Ivermectin was actually treating ringworm, which leaves them susceptible to klebsiella, Boren said.
‘‘It is imperative that a full season of subantarctic fieldwork be conducted in 2022-23,’’ wrote Young and Manno.