Advanced

Fishing from space : mackerel fishing in Icelandic waters and correlation with satellite variables

Agustsdottir, Kristin LU (2013) In Student thesis series INES NGEM01 20131
Dept of Physical Geography and Ecosystem Science
Abstract
As concentrations of measured CO2 in the atmosphere reach a record high it is important to attempt all possible efforts to reduce the emissions of greenhouse gases (GHG) in all aspects of industry. The fishing sector contributes 15% of total GHG emission in Iceland, with the majority originating from fishing vessels using fossil fuel. The relationship between catching locations of Atlantic Mackerel (Scomber scombrus) in Icelandic waters and satellite remote sensing variables was explored. The aim was to provide information for possible fish¬eries forecasting, which could facilitate reduced energy consumption in Icelandic fishing vessels. The hypothesis was that satellite variables were a valuable source of information for determining... (More)
As concentrations of measured CO2 in the atmosphere reach a record high it is important to attempt all possible efforts to reduce the emissions of greenhouse gases (GHG) in all aspects of industry. The fishing sector contributes 15% of total GHG emission in Iceland, with the majority originating from fishing vessels using fossil fuel. The relationship between catching locations of Atlantic Mackerel (Scomber scombrus) in Icelandic waters and satellite remote sensing variables was explored. The aim was to provide information for possible fish¬eries forecasting, which could facilitate reduced energy consumption in Icelandic fishing vessels. The hypothesis was that satellite variables were a valuable source of information for determining viable fishing grounds in Icelandic waters.
The variables explored were sea surface temperature (SST), chlorophyll (CHL), photosyn-thetically available radiation (PAR), water leaving radiance (L443) and down welling diffusion attenuation coefficient (kd490). The spatial resolution was about 4.6 km and temporal resolution 1 day. Effects of decreased spatial and temporal resolution were also explored.
Binomial generalized additive models were created to identify the possible relationship with fishing locations represented as absence or presence of mackerel catches. Seven day PAR was the strongest single variable, explaining 47% of deviance, with the spatial variables latitude and longitude incorporated. The most successful multiple variable models included one or seven day averages of PAR and SST and seven day averages of L443, explaining 48% of deviance. Decreasing temporal resolution to 7 days improves the predictive ability of all variables. Decreasing spatial resolution to 3*3 cells does not decrease or increase the predictability to any extent.
In order to estimate the usefulness of global data sets in local situations, a correlation of observed and remotely sensed CHL in Icelandic waters was estimated. Results on a minor sample size revealed a strong significant correlation, suggesting that global datasets were useful in local situations around Iceland.
The satellite variables explored significantly contribute to a model explaining the absence and presences locations for mackerel fishing in Icelandic waters. Mackerel catches were most successful in a temperature range of 7.5°-13°C where there were high amounts of incoming visible solar radiation and intermediate concentration of phytoplankton. Clear waters due to little absorption as well as turbulent water with high scattering also had effects. This suggested that mackerel caught in Icelandic waters was more dependent on visual foraging than previously considered. (Less)
Abstract (Icelandic)
Styrkur CO2 í andrúmslofti mældist í fyrsta sinn yfir 400 ppm í maí 2013. Með Kyotobókuninni frá 1997 hafa þjóðir heimsins hafa skuldbundið sig til að draga úr losun gróðurhúsalofttegunda. Ísland er þar á meðal. Sjávarútvegurinn leggur til um 15 % af heildarlosun gróðurhúsalofttegunda á Íslandi. Meiri hlutinn kemur til vegna brennslu jarðefnaeldsneytis skipaflotans. Ein af tíu lykilaðgerðum Umhverfis- og auðlindaráðuneytisins til að draga úr losun gróðurhúsalofttegunda er að leita leiða til að draga úr útblæstri íslenska fiskiskipaflotans.
Tengsl milli veiðistaða makríls (Scomber scombrus) á Íslandsmiðum og fjarkönnunarganga frá gervitunglum var könnuð. Markmiðið var að afla upplýsinga fyrir mögulegar fiskiveiðispár, sem geta stuðlað að... (More)
Styrkur CO2 í andrúmslofti mældist í fyrsta sinn yfir 400 ppm í maí 2013. Með Kyotobókuninni frá 1997 hafa þjóðir heimsins hafa skuldbundið sig til að draga úr losun gróðurhúsalofttegunda. Ísland er þar á meðal. Sjávarútvegurinn leggur til um 15 % af heildarlosun gróðurhúsalofttegunda á Íslandi. Meiri hlutinn kemur til vegna brennslu jarðefnaeldsneytis skipaflotans. Ein af tíu lykilaðgerðum Umhverfis- og auðlindaráðuneytisins til að draga úr losun gróðurhúsalofttegunda er að leita leiða til að draga úr útblæstri íslenska fiskiskipaflotans.
Tengsl milli veiðistaða makríls (Scomber scombrus) á Íslandsmiðum og fjarkönnunarganga frá gervitunglum var könnuð. Markmiðið var að afla upplýsinga fyrir mögulegar fiskiveiðispár, sem geta stuðlað að minni orkunotkun fiskiskipa. Tilgátan var sú að fjarkönnunargögn úr gervitunglum séu uppspretta gagnlegra upplýsinga til að ákvarða vænlegar fiskislóðir á Íslandsmiðum.
Fimm gervitunglabreyturnar voru kannaðar: yfirborðshiti sjávar (SST), magn blaðgrænu (CHL), styrkur ljóstillífunargeislunar (PAR), full staðlaður geislunarljómi endurkastaðs ljóss frá vatni (L443) og stuðull fyrir niðurstreymi dreifðrar geislunar í vatni (kd490). Svæðisupplausn gervitunglabreytanna var um 4.6 km og tímaupplausn 1 dagur. Áhrif þess að minnka bæði svæðis –og tímaupplausn voru einnig könnuð.
Tengsl gervitunglabreyta og veiðistaða makríls voru könnuð með tvíkostadreifðu GAM-líkani (Generalized Additive Model). Háða breytan var veiðistaðsetningar sem voru skilgreindar sem veiddur makríll eða enginn veiddur makríll. Óháðar breytur voru gervitunglabreyturnar með mismunandi svæðis – og tímaupplausn. Sjö daga meðaltal ljóstillífunargeislunar var sú einstaka breyta sem skýrði best makrílveiðar. Það módel með fleiri en einni óháðri breytu sem skýrð best makrílveiðar var módel með eins eða sjö daga meðaltal fyrir ljóstillífunargeislun og yfirborðssjávarhita og sjö daga meðaltal fyrir full staðlaðan geislunarljóma endurkastaðs ljóss frá vatni. Minni svæðisupplausn hafði ekki mikil áhrif á hæfileika gervitunglabreytanna til að skýra makrílveiðar en minni tímaupplausn frá einum degi til sjö daga bætti hæfileika flestra breytanna.
Gervitunglabreyturnar sem voru notaðar komu úr stórum gagnasöfnum sem eru unnin fyrir heiminn í heild sinni. Til að meta hversu árangursrík slík gagnasöfn eru við staðbundnar aðstæður eins og á Íslandsmiðum voru tengsl milli blaðgrænu sem mæld er í sjó á Íslandsmiðum og magn blaðgrænu sem mæld er með gervitunglum á sömu stöðum borin saman. Niðurstöður, sem byggðu á litlu úrtaki, sýndu sterka marktæka fylgni.
Gervitunglabreyturnar bættu marktækt módel til að skýra staðsetningu makrílveiðistaða. Makrílveiðar voru árangursríkastar við yfirborðshita sjávar frá 7,5°C – 13°C þar sem styrkur sólarljóss var mikill og þar sem magn blaðgrænu var í meðallagi. Tærari sjór og einnig sjór þar sem mikið endurkast á sér stað hefur líka áhrif. Þessar niðurstöður gefa til kynna að makríll sem veiddur er á Íslandsmiðum sé meira háður sjón við fæðuöflun en hingað til hefur verið álitið. Flestar heimildir segja að makríllinn afli fæðunnar fyrst og fremst með því að sía hana. (Less)
Please use this url to cite or link to this publication:
author
Agustsdottir, Kristin LU
supervisor
organization
course
NGEM01 20131
year
type
H2 - Master's Degree (Two Years)
subject
keywords
chlorophyll, downwelling diffuse attenuation coefficient, photosynthetically available radiation, water leaving radiance, physical geography and ecosystem analysis, sea surface temperature, Atlantic Mackerel, Scomber scombrus, Icelandic waters, satellite variables, remote sensing
publication/series
Student thesis series INES
report number
279
funder
AVS R&D Fund of Ministry of Fisheries in Iceland
funder
Landsvirkjun Energy Research Fund
language
English
id
3815009
date added to LUP
2013-06-19 13:29:47
date last changed
2019-01-14 11:00:13
@misc{3815009,
  abstract     = {As concentrations of measured CO2 in the atmosphere reach a record high it is important to attempt all possible efforts to reduce the emissions of greenhouse gases (GHG) in all aspects of industry. The fishing sector contributes 15% of total GHG emission in Iceland, with the majority originating from fishing vessels using fossil fuel. The relationship between catching locations of Atlantic Mackerel (Scomber scombrus) in Icelandic waters and satellite remote sensing variables was explored. The aim was to provide information for possible fish¬eries forecasting, which could facilitate reduced energy consumption in Icelandic fishing vessels. The hypothesis was that satellite variables were a valuable source of information for determining viable fishing grounds in Icelandic waters. 
The variables explored were sea surface temperature (SST), chlorophyll (CHL), photosyn-thetically available radiation (PAR), water leaving radiance (L443) and down welling diffusion attenuation coefficient (kd490). The spatial resolution was about 4.6 km and temporal resolution 1 day. Effects of decreased spatial and temporal resolution were also explored. 
Binomial generalized additive models were created to identify the possible relationship with fishing locations represented as absence or presence of mackerel catches. Seven day PAR was the strongest single variable, explaining 47% of deviance, with the spatial variables latitude and longitude incorporated. The most successful multiple variable models included one or seven day averages of PAR and SST and seven day averages of L443, explaining 48% of deviance. Decreasing temporal resolution to 7 days improves the predictive ability of all variables. Decreasing spatial resolution to 3*3 cells does not decrease or increase the predictability to any extent. 
In order to estimate the usefulness of global data sets in local situations, a correlation of observed and remotely sensed CHL in Icelandic waters was estimated. Results on a minor sample size revealed a strong significant correlation, suggesting that global datasets were useful in local situations around Iceland. 
The satellite variables explored significantly contribute to a model explaining the absence and presences locations for mackerel fishing in Icelandic waters. Mackerel catches were most successful in a temperature range of 7.5°-13°C where there were high amounts of incoming visible solar radiation and intermediate concentration of phytoplankton. Clear waters due to little absorption as well as turbulent water with high scattering also had effects. This suggested that mackerel caught in Icelandic waters was more dependent on visual foraging than previously considered.},
  author       = {Agustsdottir, Kristin},
  keyword      = {chlorophyll,downwelling diffuse attenuation coefficient,photosynthetically available radiation,water leaving radiance,physical geography and ecosystem analysis,sea surface temperature,Atlantic Mackerel,Scomber scombrus,Icelandic waters,satellite variables,remote sensing},
  language     = {eng},
  note         = {Student Paper},
  series       = {Student thesis series INES},
  title        = {Fishing from space : mackerel fishing in Icelandic waters and correlation with satellite variables},
  year         = {2013},
}