A digital image of a scanned British Admiralty chart. (UVic geography department)

1858 Naval maps combined with satellite data helps researchers map kelp bed health

UVic researchers have come up with a novel way of collecting data

A new tool for understanding kelp decline and its impact on B.C. coastal habitats has been developed by combining old naval charts with the latest satellite data.

Maycira Costa, a professor in the University of Victoria’s geography department, was in a colleague’s office when she noticed a beautiful old nautical chart on the wall from 1903.

“As I looked I saw drawings of plants on the coast. I have a separate satellite project and realized the areas on the map were the same as the satellite pictures.”

ALSO READ: Consultation process for marine conservation area on Vancouver Island continues after five years

The British Navy of the late 19th century was famous for its fastidious mapping, and they mapped kelp beds extensively as they presented a hazard to shipping. Costa realized the old maps were a potential gold mine of valuable data.

“I said, ‘Wow that’s amazing. Can we find maps for the whole Canadian coast?’”

Costa contacted the Canadian Hydrographic Service, who fortuitously had similar ideas, and were busy scanning and making digital copies of all the B.C. coastal charts they could find.

The process took several months, but at the end of it, the researchers were able to assess the accuracy of the maps.

They found that the maps were generally accurate and presented a viable baseline of data they could work from. Costa said modern biometric data shows that B.C. kelp beds run to a maximum depth of 30 metres. The British were known to get depth sounds and so when the researchers saw the British had noted kelp depths of 20 to 25 metres they knew the beds were likely to have been correctly recorded. Anything noted as deeper than 30 metres were not considered reliable.

ALSO READ: ‘Snow, melt, freeze, snow, melt, freeze’ leaves daffodils unpicked on the Peninsula

The researchers used British Admiralty charts from 1858 to 1956 and the maps were so accurate, later generations of maps built on the work of earlier cartographers and presented an accurate snapshot of kelp beds over the 100 year period.

Once the maps had been checked, modern satellite images of the same coastline were transposed over them, showing the differences in coastline and kelp beds.

Asked whether the maps hinted at any sunken treasure galleons, Costa laughed and said, “No sunken treasure ships but it was interesting as some features of the B.C. coastline didn’t match.”

She said that either there were errors during mapping or the maps could show sea level rises, erosion and sediment deposits over the generations. This is currently being studied.

ALSO READ: Groups target Health Canada approval of weed killer

The old nautical charts have proved especially helpful as they present an almost complete picture of kelp beds from their time, while there is currently no modern B.C. kelp bed map.

Costa has been part of a study that monitored kelp beds in Cowichan Bay from 2004 to 2017. During that time she has seen the kelp beds decrease and recover with fluctuating water temperatures. The new data, allied with this study should provide a more complete picture of a fragile ecosystem that is critical to species such as salmon and herring.

Costa said she enjoyed the novel way of collecting data, “We use high-tech satellites 700 kilometres above the earth’s surface, but then I get excited when I see the old historical charts and hold them in my hands.”



nick.murray@peninsulanewsreview.com

Like us on Facebook and follow us on Twitter

 

Maycira Costa on board a boat on the B.C. coastline. (Maycira Costa)

Just Posted

Pipeline protestors plan march as Trudeau gives Trans Mountain the go-ahead,

20 kilometre march to protest the pipeline starts in Victoria, ends on Saanich Peninsula

Summer transit route increases hit Greater Victoria hotspots starting July 1

Canada Day routes operate on Sunday-level service with select late-night service

Saanich jam stand at the centre of controversy prepares to close

Staff review of roadside stand legislation too late for Little

Union Club of B.C. votes in its first female president

16-year member Grace Van den Brink previously served as vice president

French Open at Bear Mountain serves a winner

The US Open is scheduled for Sept. 3 to 8 on the hardcourts at Henderson Park in Oak Bay

VIDEO: Trans Mountain expansion project gets green light, again

Prime Minister Justin Trudeau announced the decision in Ottawa on Tuesday afternoon

Greater Victoria wanted list for the week of June 18

Greater Victoria Crime Stoppers is seeking the public’s help in locating the… Continue reading

POLL: Do you support the government’s decision to approve the Trans Mountain pipeline expansion?

The federal government announced Tuesday its approval for the Trans Mountain pipeline… Continue reading

VIDEO: Firefighters stop blaze from spreading after BMW crashes at Saratoga Speedway

Victoria-based businessmen were ‘corner training’ on Father’s Day when incident took place

Demonstrators on either side of Trans Mountain debate clash in Vancouver

Crowd heard from member of Indigenous-led coalition that hopes to buy 51% of expansion project

Grieving B.C. mom hopes Facebook message leads to new investigation into son’s Surrey homicide

Criminal Justice Branch didn’t lay charges, concluding no substantial likelihood of murder or manslaughter conviction

Ginger Goodwin’s Cumberland cemetery grave desecrated

Just days before the Miners Memorial weekend, Ginger Goodwin’s grave has been… Continue reading

B.C.’s measles vaccination program gains traction in May

More than 15,000 doses of the MMR vaccine has been administered across the province

B.C. farmers concerned Agricultural Land Reserve changes choking their livelihood

Dozens voice concerns at special meeting hosted on Vancouver Island

Most Read