Transcript SIO 296 Concept Lecture II

27957, 27960: nesting grounds in JamursbaMedi, Papua, Indonesia
27957: Foraging grounds: Oregon,
Washington, Hawaii?, temperate eastern
pacific.
27960: Foraging grounds: Malaysia,
Philippines
Countries: USA, Indonesia, Palau?, PNG, FS
Micronesia, Marshall Islands, Philippines,
Malaysia, Vietnam?, Thailand
27960
27957
GIS!
RFMOs: APFIC, FFA, WCPFC, SPC, IATC, SPRFOM,
SEAFDEC, CCBST
More data: more tracking data, fisheries data on interactions
5394: PNG, Solomon Islands, Vanuatu, Fiji, NZ, New
Caledonia
Overlapping EEZ’s
• Agreement (STP, Nigeria)
• Dispute (South China Sea)
SIO 296 Concept Lecture II
Phaedra Doukakis, Ph.D.
January 15, 2010
Managed species don’t exist in
isolation
• Highly Migratory Species are a shared
resource existing within and outside of
our/an EEZ and can require transboundary management.
• Discussed tools to inform and perform
management: tagging and tracking to
understand spatial structure; RFMO’s to
manage trans-boundary stock.
http://tagagiant.org/Summary_Nature.shtml
Building upon this
• More on how understanding spatial
structure is necessary and how it’s
detected.
• Continuing to move toward holistic
management: ecosystem based fisheries
management (EBFM).
Traditional Approach to Fisheries
Stock Assessment Model
Balance
reproduction and
growth with
mortality to sustain
population biomass
Density Dependant Mortality
Mortality and
reproduction
aren’t
independent:
competition and
predation, abiotic
factors; density
dependant.
Sustainable Yield
• What is the largest fishing mortality rate
that can be offset by increased population
growth?
Population reaches maximum due
to carrying capacity;
Growth rate peaks and declines
due to density dependence
The MSY in biomass occurs at a
level of fishing mortality that
places the population at this
intermediate size.
Reference Points
• Better to think of MSY as a percentage of the
population rather than a fixed figure because
populations fluctuate.
• Think of it as a limit (limit reference point) rather
than target (target reference point)
– Reference points begin as conceptual criteria which
capture in broad terms the management objective for
the fishery which are then turned into technical
criteria, e.g. objective is maximize yield = MSY.
Overly Simplistic
• Parameters such as abundance and
population growth are hard to estimate.
• A species subject to a fishery interacts
with other ecosystem components (prey,
predators, abiotic factors) that influence
model parameters; it doesn’t exist in
isolation…
Ecosystem Based Fishery
Management
• Ill-defined concept; many attempts in the
last 10 years.
• Managing fishery within an ecosystem
context, taking into account ecological
interactions, sensitive species and
habitats, environmental forcing and
effects, social and economic structures
and impacts.
• Requires new objectives and tools.
Manage complexity
Ecosystem Based Management
Pikitch et al. 2004 Science
• reversing the order of management priorities to
start with the ecosystem rather than the target
species.
• i) avoid degradation of ecosystems;
• ii) minimize the risk of irreversible change to
natural assemblages of species and ecosystem
processes;
• (iii) obtain and maintain long-term
socioeconomic benefits without compromising
the ecosystem; and
• (iv) generate knowledge of ecosystem
processes sufficient to understand the likely
consequences of human actions.
Irreversible Change?
• Harvest of the Namibian sardine and other small
pelagics in the Northern Benguela current ecosystem:
shift in the species composition of the system, with
sardine and anchovy replaced by the pelagic goby as the
principle forage species.
• Additive effects of fishing and environmental anomalies:
small pelagics did not recover after fishing curtailed,:
sardines at only 10% of their former abundance.
• Declines of Namibia’s seabirds (Crawford 2007;
Crawford et al. 2007).
• Intensive fishing altered the trophic control mechanism
so that environmental factors exert a greater influence
(Watermeyer et al. 2008)?
• Other examples of ecosystem regime shifts? Cod? Top
predators? Regime shift to another state.
Ecosystem Based Management
Pikitch et al. 2004 Science
• Develop community and system indicators
of “health”.
• Precautionary, adaptive management
(feedback loops).
Crowder et al. 2008
• Manage the direct and indirect effects of
commercial fisheries… include impacts of
bycatch, recreational fisheries, artisanal
fisheries, and environmental change that
can be large but unanticipated .
• Synergistic effects of fishing,
environmental variation, and climate
change increasingly threaten marine
ecosystems and complicate management.
Francis et al. 2007 Fisheries: 10
commandments of EBFM
• Holistic, risk-averse, and adaptive.
• Maintain old-growth age structure in fish populations.
• Characterize and maintain the natural spatial structure of
fish stocks.
• Characterize and maintain viable fish habitats.
• Characterize and maintain ecosystem resilience.
• Identify and maintain critical food web connections.
• Account for ecosystem change through time.
• Account for evolutionary change caused by fishing.
• Implement an approach that is integrated,
interdisciplinary, and inclusive.
Australia
• Considers the impact that fishing has on
all aspects of the marine ecosystem, not
just the target species.
• Ecological risk assessment to evaluate
the ecological effects of fishing
• Managing by-catch
• Avoiding Protected Species
North Pacific Fishery Management
Council
• Groundfish:
– Setting TACs (and reference points) low
and precautionary.
– Minimizing by-catch.
– Establishing MPA’s for habitat
preservation.
– Avoiding Protected species.
• Currently defining for the Aleutian
Islands
Marine Stewardship Council
• The fishery does not cause serious or
irreversible harm to the key elements of
ecosystem structure and function.
• There is adequate knowledge of the
impacts of the fishery on the ecosystem.
Antarctic and CCAMLR
• Set fishing limits on krill at about 9% of
existing biomass (4 million tons).
• Safeguards percent of biomass for
predators.
• Allocate quota among small scale
management units to protect spatially
confined predators; data requirements
substantial.
Magnuson Stevens Act
Reauthorization
• Mandated ecosystem management report.
• Report indicated more data are needed on
fished species and ecosystems; modelers
need these data.
• http://spo.nwr.noaa.gov/tm/TM96Web.pdf
• Still being defined in the USA.
Identify key management
objectives and constraints,
identify appropriate indicators
and management thresholds,
determines the risk that
indicators will fall below
management targets, and
combines risk assessments of
individual indicators into a
determination of overall
ecosystem status. The
potential of different
management strategies to
alter ecosystem status is
evaluated, and then
management actions are
implemented and their
effectiveness monitored. The
cycle is repeated in an
adaptive manner.
Levin PS, Fogarty MJ, Murawski SA, Fluharty D (2009) Integrated Ecosystem Assessments: Developing the Scientific Basis
for Ecosystem-Based Management of the Ocean. PLoS Biol 7(1): e1000014. doi:10.1371/journal.pbio.1000014
Research & Tools
• More on the ecosystem effects of fishing –
metrics of ecosystem health.
• Spatially explicit multi-species assessments.
• Understanding and accounting for variability.
• Tools we have now:
– single stock assessment but different objectives
– conservative TAC’s and reference points (Atlantic
mackerel SSBMSY twice as high when predation is
considered (Moustahfid et al. 2009)
– spatial limits
– adaptive management with ecosystem monitoring.
Demonstrating the complexity…
• Lecture on management of HMS:
– Getting the data needed for assembling an
ecosystem plan:
• Stock structure
• Predatory prey relationships (and how they may
shift due to climate)
• Abundance estimates
• Forage species: managing fisheries in the
context of environmental forcing.