The Spot Prawn Fishery: A Status Report - Earth Economics

The Spot Prawn Fishery: A Status Report
types) has been a cause for ecological concern
for centuries. As early as 1376, the English House
of Commons protested to the King about the likely
damage that fishing boats dragging trawl nets
were causing to seafloor vegetation (Galvin 1996).
Despite the prevalence of longstanding concerns
and disputes about the environmental effects of
trawling, there have been few attempts to quantify
trawling damage. The studies that do exist provide
data that support the need for a more sustainable
approach. A number of trawling bans have been
established around the world to protect benthic
organisms and ecosystems from the potentially
destructive effects of trawling. Localized trawling
bans exist in Australia, Indonesia, Canada, and
in several states in the United States, including
Alaska, Washington, North Carolina, and Florida.
Only a small percentage of overall effort in the
spot prawn fishery is trawl effort. Spot prawn
trawling bans are in place for ecological reasons
in Alaska, British Columbia, and Washington’s
inshore fishery (a phase-out plan is being developed
for the coastal fishery). Many of the managers
and scientists interviewed for the Status
Report questioned whether, given spot prawn
biology, a trawl fishery was even “appropriate.”
Spot prawn trawl gear is non-selective and
destructive, an important ecological consideration
given the sensitivity of the spot prawn habitat
and associated species (e.g., bocaccio). Fishing for
spot prawns with traps or pots is more likely to
result in an ecologically sound and economically
viable fishery for spot prawns and for ecologically
interrelated species such as rockfish. Spot prawn
trap fisheries are already viable and lucrative.
Moreover, trap-caught prawns offer a range of
higher-value product types that could result in
an even more profitable fishery in the long run.
Serious consideration should be given to phasing
out the trawl fishery throughout the spot prawn’s
range. There is no doubt that there will be shortterm
economic costs associated with phasing
trawls. On the other hand, reducing the ecological
impact of fishing has been proven time and again
to be investment in natural capital that provides a
more than substantial return in the long run.
1.4 Management should be Systemic and
Spatial in Orientation
Precautionary management is spatial and multidimensional
in orientation and calls for concentration
on spatial stock structure and the processes
or factors that influence it. Management systems
that emphasize the use of overall quotas
have not proven particularly useful in the management
of shellfish species that have a primarily sessile
adult phase—a characteristic that often makes
these types of animals susceptible to serial depletion
(Orensanz et al. 1998). According to Garcia
(1996), the potential risk of negatively affecting
through fishing pressure the fecundity of latematuring
shrimp like spot prawns is high.
Spot prawn fecundity is naturally very low.
Compared to finfish like cod, the number of eggs
released by a female spot prawn is significantly
lower. The species’ reproductive potential to create
large year classes is therefore limited. This is particularly
significant for management because the fishery
tends to target larger animals; i.e., females. Dr. Paul
Anderson of the Kodiak Fisheries Research Center
argues that in targeting the largest animals, the fishery
is “hitting the oldest, most fecund, and most
valuable animals the hardest, and thereby destroying
the chances of maintaining a viable spot prawn
population.” The fishery would be better off targeting
smaller, younger male animals, some of which
would have anyway naturally died off before
changing sex and becoming sexually mature
(Paul Anderson, KFRC. Pers. comm., August 2001).
Jim Boutillier of Fisheries and Ocean Canada
offers an alternative view. In his view, future forecasting
in order to protect older, larger animals is
critical. Ensuring that the population has a sufficient
number of females, and thus is large and
strong enough to be sustainable, is essential.
British Columbia’s spawner index is a real-time
assessment tool that ensures that the brood stock
is protected and the female spot prawn population
healthy enough to sustain the population. It offers
the possibility for real-time decision-making and
management—the crux of the sustainability riddle.
The development of recruitment-related reference
points, rather than quotas, is also seen as central
to sustainable spot prawn management. In order
for quota systems to be effective, the effect of fishing
on the population needs to be fully understood.
This requires a minimum of 15–20 years of
data (Zheng et al. 1993). The authors note that the
research phase may be even longer if strong environmental
conditions or environmental variability
affect recruitment. This has been shown to be the
case with some pandalid species.
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