Orange roughy Fisheries, assessment, and management

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Orange roughyFisheries, assessment, and
management

• Allan Hicks
• Fish 323 Lecture
• Autumn 2008

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Hoplostethus atlanticus

• Bright orange/red color
• Originally called slimehead
• Long lived gt100 years
• Maturity 20-40 years
• Depths gt500 meters
• Length up to 60 cm
• Variable among populations
• Weight up to 3.5 kg

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Hoplostethus atlanticus

• Migrate to spawning grounds
• Water temps mostly 3-9 C
• Antarctic Intermediate Water
• Diverse habitat
• High content of wax esters
• Non-gas filled swim bladder
• Beneath the skin
• Small percent in fillets
• Slight laxative effect
• Used for buoyancy
• Potential use in lubricants,
• degreasers, and hand-cleaners
• Replacement for jojoba oil

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Worldwide distribution
From Branch, T. A. 2001. A review of orange
roughy Hoplostethus atlanticus fisheries,
estimation methods, biology and stock structure.
South African Journal of Marine Science
23181-203.
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Aggregating behaviour

• Form dense aggregations around seamounts, hills,
  and drop offs
• Spawning aggregations during winter
• Feeding aggregations
• May occur outside of spawning season
• Single species
• May be stratified by sex

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Aggregations

• Fish are highly mobile
• Avoidance behaviour
• Aggregations are dynamic
• Targeted by fisheries

Video of aggreagting ORH here
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Fisheries

• Bottom trawl
• Typically target aggregations
• Mature fish
• Results in large bags (gt25 tonnes)
• Also flat ground fisheries
• Longer tows with lower catch-rates
• Catch includes smaller, immature fish
• Mostly out of spawning season

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Worldwide Catches
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Issues

• Long lived, slow growing, late maturing
• Low productivity means low sustainable yields
• Research/Data
• Fishery-independent data is expensive
• Fishery-dependent data is less reliable
• Uncertainty about some life-history parameters
• International fisheries management
• IUU fishing illegal, unreported, and unregulated
• Environmental effects
• Bottom trawling
• Little interaction with birds and mammals

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New Zealand orange roughy fisheries

• NZ EEZ 1.2 million square miles
• 15 times the size of NZs land mass
• Widely distributed around NZ
• Along 1000m contour
• 7 management areas
• 9 stocks assessed
• Catches started in late 1970s
• Chatham Rise Mid-East Coast are the major
  contributors
• New areas still being discovered
• 6th most valuable export in 2007

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NZ orange roughy catches
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New Zealand fisheries management

• Quota Management System (QMS)
• Individual Transferable Quotas (ITQs)
• First implemented in 1986
• Company individual quotas in 1983 to deepwater
  fishery
• Quota Shares
• Property right representing quota owners share
  of the fishery
• Annual Catch Entitlement (ACE)
• Right to take a certain weight of the fishstock
  during the fishing year
• Determined from quota shares and the Total
  Allowable Commercial Catch (TACC)
• Can also be obtained by purchasing from an ACE
  owner
• Catches in excess of ACE are charged deemed
  values
• Cost recovery of services from stakeholders

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Cost recovery

• http//www.fish.govt.nz/en-nz/SOF/CostRecovery.htm

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NZ fisheries management

• Ministry of Fisheries (MFish)
• Governments principal adviser on New Zealands
  fisheries management
• Consults with other stakeholders, iwi, and others
• Fisheries Act 1996 (section 13)
• Minister set a Total Allowable Catch (TAC)
  that maintains, rebuilds, or reduces a fish stock
  to a level at or above that which can produce the
  maximum sustainable yield (MSY)
• Fisheries plans
• Tailored management under the framework of the
  QMS

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NZ orange roughy management process

• Planning
• Collect data
• Analyze data
• Advise the Minister of Fisheries
• Minister of Fisheries decides on TAC

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Industry involvement

• Deepwater Group Ltd
• Represents the interests of quota holders with
  Government and government departments
• Undertakes fisheries research and stock
  assessment programs
• Implements and monitors fisheries management
  programs
• Works on to manage and minimize any adverse
  environmental affects

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Planning

• Fishery plans are not common in ORH fisheries
• Research planning
• Every year
• Focus on valuable stocks and those at most risk
• Field research (surveys, sampling, etc.)
• Analyses and stock assessments
• Stakeholder involvement
• Question for stakeholders Is research cost
  beneficial

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Collecting data

• Fishery-dependent data
• Catch-per-unit-effort (CPUE)
• Lengths
• Ages

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Collecting data

• Fishery-independent data
• Egg surveys
• Trawl surveys
• Acoustic surveys
• Lengths
• Ages

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Collecting data

• Industry involvement
• Scientists funded by industry work with
  government scientists
• Fishing boats are chartered for research surveys
• Opportunistic acoustic surveys while fishing

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Analyzing data

• Statistical methods used to analyze data
• Age-structured stock assessment model
• Fit a biomass trajectory to the different data
  sources
• Determine where the current population is
  relative to original biomass and reference points
• Project the population assuming different harvest
  levels
• Two organizations involved
• National Institute of Water Atmospheric
  Research (NIWA)
• Seafood Industry Council (SeaFIC)

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Hyperdepletion

• CPUE declines faster than abundance
• Disagreement between survey abundance indices and
  CPUE
• Aggregations
• Avoidance and disruption
• Background abundance

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Trawl Surveys

• Must avoid high aggregation areas
• Useful for surveying background biomass and
  nonspawning season distribution
• Two stage stratified design
• Second stage focuses on strata with high variance

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Acoustic surveys

• Use echosounder to estimate biomass
• Hull mounted sounders or towed behind vessel
• Industry run acoustic surveys
• Under scientific supervision or opportunistic
• Combine research trawl survey and industry
  acoustic survey

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Acoustic surveys

• Plumes are dynamic and can be missed
• Echosounder does not detect near bottom targets
• Shadow zone
• Can also accidentally analyze bottom as part of
  the mark
• Target strength of orange roughy is low
• Sound does not bounce back very well
• Need to know species mix of mark
• These problems make it difficult to acoustically
  survey non-aggregated orange roughy

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Length data

• Collected from fishing vessels
• Observers on board and port sampling
• Collected during surveys
• Highly variable length distributions between
  nearby areas

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Age data

• Use otoliths (ear bones)
• Difficult to verify ageing
• A few very young fish have been analyzed
• Radiometric ageing
• Bomb calibration
• Large error in ageing

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Maturity/Selectivity

• Age and/or length data
• Selected by fishery around age 40
• Otolith transition zone
• Most mature by age 30
• Cryptic mature biomass
• Is TZ indicative of maturation?
• Do all fish spawn every year?
• Size/age separation in plumes?

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Analyzing data

• Deepwater Working Group
• Meets often to provide advice on analyses
• Busiest time is from February through May
• Members from science, government, industry, and
  NGOs
• Produces a Working Group Report
• Plenary
• Final presentations to managers of fishery
  (MFish)
• Acceptance of Working Group Report

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Harvest strategies reference points

• Percent biomass
• 20 B0
• BMCY 51 B0
• BMAY 30 B0
• Projections
• Probability that Bcurr5yrs lt Bref

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Harvest strategies reference points

• Maximum Constant Yield (MCY)
• The maximum sustainable yield under a constant
  catch strategy given an acceptable level of risk
• Current Annual Yield (CAY)
• one-year catch calculated by applying a reference
  fishing mortality, FCAY, to an estimate of
  fishable biomass present during the next fishing
  year
• FCAY is the level of fishing mortality that, if
  applied every year, would, within an acceptable
  level of risk, maximise the average catch
• Maximum Average Yield (MAY)
• Acceptable level of risk
• Falling below 20B0 less than10 of the time

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Advise the Minister of Fisheries

• MFish managers advise the Minister of Fisheries
• Stakeholders also can submit Initial Position
  Papers
• The Minister of Fisheries determines the TAC for
  the fishing year (Oct-Sep)

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Example

• MEC
• Discuss the conflict between CPUE and surveys
• Discuss the selectivity vs maturity and cryptic
  biomass
• Discuss the decision the minister had to make and
  his threshold of 20 B0 but the different cases
  showed different outcomes

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Environmental concerns

• Benthic Protected Areas (BPAs)
• Trawling typically along same lines
• Some specific seamounts/hills have been closed to
  fishing

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Summary