Salmon Farms and Sea Lice
Virtually no sea lice found in areas with no salmon farms

February 20, 2003 - VANCOUVER – Just days before an international conference here to discuss how to manage sea lice, a report by the David Suzuki Foundation shows that British Columbia’s North Coast – where there are no salmon farms – is virtually lice-free.

The Foundation sponsored the study in order to establish the natural incidence of sea lice before the salmon farming industry expands to the near-pristine area north of Bella Bella to Prince Rupert.

“This is research the government should be doing before any salmon farms are allowed in those waters, but because neither the province nor the federal government is showing that kind of leadership the Suzuki Foundation decided to do the work,” said Otto Langer, director of the Foundation’s marine conservation program.

Researchers sampled 566 juvenile salmon from 26 distinct locations of the North Coast and found only six lice in total. This is an average of 0.01 lice per fish sampled, Mr. Langer explained.

“Compared to the recent epidemics of sea lice in the Broughton Archipelago, which has the highest density of salmon farms in British Columbia, the number of sea lice we found in near-pristine waters is negligible,” he said.

Unfortunately, no government agency has been able to present baseline data for the Broughton area that would show what the natural occurrence of sea lice was before salmon farms were established in the 1980s.

“I think we can surmise, however, that the situation was comparable to what we have found on the North Coast. The collapse of pink salmon in the Broughton in 2001 was unprecedented and many scientists have said that the sea lice epidemic is likely associated with it,” said Mr. Langer, who will attend the conference this weekend hosted by the University of BC.

The Foundation study, ‘A Baseline Report of the Incidence of Sea Lice on Juvenile Salmonids on British Columbia's North Coast’, is the first in British Columbia to collect information on sea lice conditions in pristine or near-pristine habitat before the arrival of salmon farms.


Executive Summary

In September 2002, the government of British Columbia lifted a seven-year ban on new salmon farms. Many people, from First Nations and fishermen to environmentalists and residents of coastal communities, feared that the provincial government would allow the expansion of salmon farms into areas currently free of farms, without addressing the issue of sea lice or conducting baseline studies on the natural incidence of sea lice.

The David Suzuki Foundation sponsored this study to determine the natural background levels of lice infestation before salmon farms intervened in the natural ecology of the area slated for salmon net-cage expansion on BC’s North Coast, south of Prince Rupert. Both the governments of Canada and British Columbia were invited to participate in this study but declined.

The development of intensive net-cage salmon farm operations in the Broughton Archipelago area of the British Columbia coast has appeared to affect juvenile wild salmon migrating from their natal streams to the open ocean. Many of these floating salmon farms are situated directly on the migratory routes salmon follow to the ocean.

Outbreaks of sea lice, some at epidemic levels, have been recently documented around salmon farms in the Broughton Archipelago, and they are among the gravest problems for juvenile wild salmon, especially the smaller pink and chum salmon. As few as two lice can kill a juvenile salmon. In June 2001, at the height of a huge lice infestation in the Broughton Archipelago, as many as 23 lice were counted on individual juvenile salmon. The greatest concentration of salmon farms in British Columbia is currently found in this area.

Field studies for this report were conducted in May and June 2002 at 26 different locations and involved beach seining and dip nets to remove juvenile salmon from the water. During this time, 435 pink salmon, 64 chum, 58 sockeye and 9 other salmonids were sampled and analyzed for sea lice. Further observations, including the presence of sensitive and unique habitats, were reported as part of this study.

The natural background levels of sea lice infestation per fish determined within this study were miniscule in comparison to infestation rates in the Broughton Archipelago. In total, six sea lice were found on 566 juvenile salmonids for an average incidence of infestation of 0.01 lice per salmon. None of these lice were Lepeophtheirus salmonis which is the predominant sea lice species that has infested juvenile pink salmon in the areas of the Broughton Archipelago where the highest density of salmon farms are found. In the Broughton area, the average incidence was 11.21 lice per fish in 2001 with a high of 23 per fish, and an average of 4.10 lice per fish in 2002. This infestation rate is 1,120 and 410 times higher, respectively, than that documented in this study for an area without salmon farms.

These results are extremely significant and indicate that juvenile salmonids adjacent to extensive salmon farm operations, such as in the Broughton Archipelago, are exposed to much higher levels of sea lice infestations than is found in more pristine, natural habitat where salmon net-cage aquaculture is absent.

Currently, there is a dearth of knowledge on the existing natural aquatic environment – marine and freshwater - of BC’s North Coast, where the salmon farming industry is slated to expand. This makes the meaningful assessment of potential risks and risk-adverse strategies in this near-pristine area almost impossible before the industry arrives.

This report is the first in British Columbia to collect information on sea lice conditions in pristine or near-pristine habitat before the arrival of the salmon net-cage industry. One of the report’s greatest values will be the potential ability to compare the results with already developed and impacted areas.

Research for Salmon Farms and Sea Lice was conducted by David Ralston and Bart Proctor of North Coast Resource Management

For more information, please contact Otto Langer or Jean Kavanagh at
604-732-4228 or Ms. Kavanagh at 604-721-9332 cell. DOWNLOAD REPORT