Report: http://www.ices.dk/reports/FTC/2005/SGUFM05.pdf

Fishing mortality (F) is defined by The Study Group on Unaccounted Mortality in Fisheries (ICES, 1995) as "'The sum of all fishing induced mortalities occurring directly as a result of catch or indirectly as a result of contact with or avoidance of the fishing gear'"

They give the equation:
F = Fc + Fb + Fd + Fe + Fo + Fg + Fa + Fh, where
Fc == landed catch
Fb == illegal, misreported, unreported
Fd == discard mortality: mortality from discards
Fe == escape mortality: mortality of fish that escape capture but still die
Fo == drop out mortality: fish that are caught in the net but are killed and fall out of the net before being brought aboard
Fa == avoidance mortality: death rate associated with the stress that fishing causes fish (i.e. avoiding the net)
Fg == ghost fishing mortality: fish that die in "ghost gear"--gear that is lost at sea
Fh == habitat degradation mortality

The most important of these are:
Fb, Fd, Fe, and Fg

Note: UFM == unaccounted fishing mortality

Illegal, Unreported, and Unregulated fishing (IUU):

  • IUU is a major source of uncertainty in stock assessments (they cite Bray 2000; Evans 2000; Ices, 1994, 2000, and 2004)
  • Most information available is anecdotal
  • Most estimates are fishery-specific
  • FAO estimates that LEGAL and IUU kills about 8 million TONNES per year
    • Mostly Tuna and deep sea species
    • "Constitutes a doubling of catch in the last 20 years" (they cite Schmidt 2004)
    • CCAMLR estimates the amount of IUU toothfish taken between 1997 and 2000 to be about 90,000 tonnes (more than 2x the registered catch levels)
    • NEAFC says that almost 20% of the 2001 trade in redfish was IUU (they cite NEAFC, 2002)
    • ICCAT (the tuna people) estimates that 18% of the tuna catch is IUU
  • For most ICES stocks, IUU is responsible for "the single largest potential source of UFM" for the stock
  • AFWG reports that 90 to 115 kilotonnes (I don't know if that was a unit, but it is now) of north east artic cod is IUU since 2002
  • WGBFAS estimates that true baltic cod catches are 35-45% bigger than reported
  • NWWG used satellite imagery to find that Redfish catches may be 25% greater than reported
  • Other stock assessment working groups know that IUU is a major confounding factor, but have no way to quantify it (I think that if ICES can't get the data, we are toast)

On the international scene:

  • IUU was formally recognized as a fishing problem at an FAO conference in 1992
    • Schmidt, 2004 has a "brief" overview on subsequent regulations
  • International Plan of Action for IUU Fishing (aka IPOA-IUU) is key
    • defines stuff:
      • Illegal fishing: fishing that is not in accordance with local laws, or fishing by a boat that is not allowed in those waters. (I guess those are the same)
      • Unreported: either unreported or misreported catch data
      • Unregulated: fishing "conducted in stocks for which no state (or RFMO) has taken responsibility for their management and conservation; or by vessels without nationality (or flying the flag of a state not party to any relevant RFMO) and who therefore do not consider themselves bound by the relevant national laws (or RFMO regulations)."
    • goal is to "'prevent, deter, and eliminate IUU fishing'"

ICES working group concluded that science can contribute to the reduction of IUU by:

  • Identifying affected stocks and fisheries
  • Formulating practical solutions
  • Developing approaches to managing the uncertainties that IUU creates

Note: IUU is possibly driven by (they recommend Bray 2000 and Schmidt 2004 for more info):

  • Ineffective Management
  • Fleet Overcapacity
  • Bad enforcement
  • economic incentives from flag hopping supporting states
  • economic pressures
  • LACK OF STIGMA ASSOCIATED WITH IUU--"UNDERESTIMATION OF ENVIRONMENTAL AND SOCIAL IMPACTS"
  • IUU can start a "self propagating cycle" (they cite Schmidt 2004)
    • IUU by one fisherman induces other fishermen to go IUU
    • More IUU --> more uncertainty in estimates --> stricter regulations --> more IUU
    • Paton, 2005 says that IUU can become part of the culture of a fishing village

Estimating IUU

  • "In a review for the FAO-IPOA, Evans (2000) explains that considerable progress could be made in accounting for IUU fishing by simply improving monitoring and data collection programs"
    • suggest using "satellite imagery vessel detection systems" to get more data
  • Statistical Methods
    • Compare catch data to trade data
    • Estimate IUU: estimate number of unregulated boats, extrapolate catch rates
      • "reliant on the collection of a complex array effort and catch data"
      • assumes that legal fishing is representative of IUU
  • Model Methods
    • population models: use survey data and CPUE, find difference between predicted mortality rate and actual mortality rate
      • result could just be that the model was not totally accurate for a given year
    • "quasi-quantitative Monte-Carlo integration": all data on UFM is combined into one analysis. "Each regieme is scored with respect to its influence on under-reporting; the values being based on available data"
      • They cite Ainsworth and Pitcher, 2005; Pitcher et al, 2002; Pitcher and Watson, 2000
      • What does ^^ even mean?
    • models of IUU behavior; surveillance encounter probabilities: consider that a surveillance ship finding a fishing ship (either leagl or not) is a "random sample." Use this to extrapolate and estimate total IUU levels. (also needs to consider that IUU boats will avoid detection more than legal boats)
      Note: population model method will give a confidence interval

Discards

  • 1994 FAO estimates are 19.9 to 39.5 megatonnes of global catch were discarded (that about 30% of the total catch)
  • estimate downgraded to 20 megatonnes in 1998; then 7.3 megatonnes in 2005 (8% global catch) (recent estimates not comparable--different methods)
  • EU Data Collection Regulation (Commission Regulation) #1639/2001 has something to do with reporting discards
  • "Still difficult to determine the accuracy...in most discard estimations"
  • Calculating: direct (stand on the boat and count) or indirect:
    • estimation of small fish discards made by comparing length measurements from observers on the boat can be compared to length estimates on land
    • I'm not sure how that would work...they cite Palsson et al, 2002; Palsson 2003; sokolov 2003
    • results from studies about fishing gear selectivity
      • I assume that this means that you look at a net and say "wow, this will give a 10% catch that is < 10 inches" and then look at catch data and say "wow, there are only 8% of that size, the rest must have been thrown back."
    • analyze catch length frequencies, assume that all fish shorter than the limit are thrown back
    • interview fishermen
    • get data from fishermen

Escape Mortality

  • "Selective fishing gears...can be justified only if significant numbers of escaping fish survive"
  • studies indicate that mortality is species-specific
    • cod, haddock survive well
    • herring does not survive well
  • Team 2 should read PDF page 16

Ghost Fishing

  • New nets are not biodegradable--when they get loose they are permanent death machines
  • In deep water (>200m), ghost fishing can last for years (several year old nets are still active in Canada)
    • In shallow water the nets get fouled
      • I don't know what fouling really means

The group working on quotas should read starting on PDF page 18.

  • No labels