Sea the future with restorative aquaculture

Waters
off B.C. have strong potential for development of commercial shellfish and
seaweed aquaculture that can also help salmon farmers

By Fabian Dawson
SeaWestNews

Shellfish and seaweed aquaculture in the
waters off British Columbia provide numerous environmental and economic
benefits to the region, says a new global study by scientists from the Nature
Conservancy and the National Oceanic and Atmospheric Administration (NOAA).

The study, the first of its kind to examine
the global potential for the concept of ‘restorative aquaculture’ found the
commercial production of shellfish and seaweed will have a net-positive effect
on the surrounding environment – filtering polluted waters and providing
habitat for commercially-important seafood species.

“Enabling conditions suggest that
development of a seaweed aquaculture sector in B.C. could provide numerous
environmental and economic benefits to the region, including enhanced nutrient
removal, habitat for commercially and recreationally important fish and
invertebrate species, and novel employment opportunities,” said Dr. Seth
Theuerkauf, aquaculture scientist at The Nature Conservancy and lead author of
the study, which was published in the journal PLOS ONE.

This study follows another by Dr. Stephen
Cross the former Industrial Research Chair for Sustainable Aquaculture at North
Island College (NIC) in B.C. which showed that seaweed aquaculture can also
play an important role for B.C.’s salmon farmers.

“The kelp-growing study involving over 40
fish farms showed good potential in growing seaweed within salmon farm
tenures,” said Dr. Cross.

It found that excess nutrients from a fish farm could act as a fertiliser for kelp, supercharging the plant’s growth. In addition to kelp providing additional revenue, it will also absorb much of a farm’s waste, and act as a carbon sink.

There are more that 630 seaweed species in
B.C.’s 20,000 km of coastline – the world’s most diverse – making it conducive
for incredible production and market opportunity, said Dr. Cross.

At the moment, seaweed harvest in the
province is mostly from the wild, totalling roughly 800 to 1,000 MT per year.

B.C.’s farmed oyster harvest totalled 7,700
tonnes in 2017 and accounted for more than one-third of the provincial
shellfish harvest. Oyster sales in B.C. generated $29 million in wholesale
value in 2017 and represented about half of the shellfish aquaculture
industry’s value.

“There exists growing interest in seaweed
aquaculture in BC, which is consistent with the identified high Restorative
Aquaculture Opportunity Index (RAOI) score identified for development of
seaweed aquaculture in this region in this study,” Dr. Seth Theuerkauf told
SeaWestNews.com by email.

“Further, across the east and west coasts,
Canada has a robust shellfish aquaculture sector,” he said.

“However, as we identified in our
global-scale analysis, many high potential regions in the developed world,
including parts of North America and Europe, shellfish and seaweed farmers in
some locations encounter an inefficient or unclear permitting process, posing
constraints to potential development of a restorative aquaculture industry.”

“Further, policy, regulatory, and
permitting processes for shellfish/seaweed aquaculture often do not yet
incorporate the potential positive environmental value farms can have into
decision-making,” he said.

Key results from the global spatial
analysis which reveals where marine aquaculture can benefit nature and people

• The opportunity for restorative
  aquaculture is truly global – there are marine ecoregions within all inhabited
  continents that have significant potential for shellfish and seaweed
  aquaculture to provide benefits to ecosystems and people.
• The top 10 highest opportunity
  regions for shellfish aquaculture development centered in Europe, Oceania, and
  North America, while the highest for seaweed aquaculture centered in Europe,
  Asia, Oceania, and South America.
• Europe’s North Sea marine
  ecoregion was consistently identified as the highest opportunity marine
  ecoregion for restorative shellfish and seaweed aquaculture development. The
  region’s coastal waters suffer some of the world’s most substantial nutrient
  pollution, widescale loss of shellfish reefs, and receives significant fishing
  pressure; commercial seaweed and shellfish farming could help to address some
  of these ecological challenges.
• Some identified high
  opportunity marine ecoregions, such as the East China Sea, already have robust
  shellfish and seaweed aquaculture industries. In such cases, the authors
  suggest reform or modifications in aquaculture practices could improve or
  optimize ecological benefits of farms.
• Other high opportunity regions,
  such as the Southern California Bight, have limited or virtually no existing
  bivalve and seaweed aquaculture operations and could environmentally and
  economically benefit from their development. And others, like Northeastern New
  Zealand, have an active shellfish aquaculture industry, but do not have an
  established seaweed aquaculture industry, which could help provide additional
  ecological function.
• Where funds to support
  traditional coastal ecosystem restoration efforts are limited—particularly
  within low or lower-middle income nations—development of shellfish and seaweed
  aquaculture sectors could present a significant opportunity to aid coastal
  ecosystem recovery efforts and economic development.

“Commercial shellfish and seaweed aquaculture present a rare opportunity to utilise commercial enterprise to directly benefit the health of our oceans and improve human wellbeing,” said Robert Jones, Global Lead for Aquaculture at The Nature Conservancy.