Status of research on the biology and ecology of opah, Lampris guttatus
Donald Hawn1, Michael Seki2, Robert Nishimoto2, Evan Howell2, and Jeffrey Polovina2 1Joint Institute of Marine and Atmospheric Research 2National Marine Fisheries Service
Photo: William Van Orden MOTIVATIONMOTIVATION
¾ VERYVERY limitedlimited informationinformation availableavailable regardingregarding thethe lifelife historyhistory andand ecologyecology ofof thisthis resourceresource
¾ SignatureSignature speciesspecies inin “deep“deep ecosystem”ecosystem” ofof tunatuna longlininglonglining
¾ PrizedPrized “exotic”“exotic” fishfish –– particularlyparticularly inin thethe HawaiiHawaii restaurantrestaurant tradetrade (Hawaii(Hawaii longlinerslongliners treattreat asas incidentalincidental catchcatch notnot “bycatch”)“bycatch”)
¾ FascinatingFascinating ecologicalecological subjectssubjects butbut quitequite aa challengechallenge toto studystudy UnitedUnited FishingFishing AgencyAgency (UFA)(UFA) landings,landings, 19871987--20022002
Opah Annual landings (lbs) 150K - 1.2M
Avg. individual fish wt. (lbs) 97 - 111 lbs
Mean price (per lb) $ 0.87 - $1.60
Annual ex-vessel revenue $240K - $1.4M
(Data courtesy R. Ito, NMFS Honolulu Laboratory) Specific project goals …
¾ Comprehensive seasonal and where possible, interannual biometric summaries and relationships (e.g., length-weight frequencies, sex ratio, etc)
¾ Determination of reproductive parameters (incl. size and age at maturity, fecundity, spawning season – Gonadosomatic Index or GSI)
¾ First cut age and growth estimations
¾ Distribution patterns, preferred habitat, faunal associations, and trophic relationships Principle project activities:
¾ Conduct comprehensive shore-based biological sampling program
¾ Perform an analysis of spatial distribution patterns, preferred habitat, faunal associations, and trophic relationships UFA: ¾ Catch and size composition ¾ For opah – sex ratio ¾ For monchong – species differentiation
¾ Special effort to link UFA metrics with biological sampling Buyers/Dealers
¾ Length, Weight, Sex ¾ Morphometrics ¾ Biological samples for reproduction and ageing Opah, Lampris guttatus ¾ aka ‘moonfish’
¾ believed to be generally solitary (?? – small groups)
¾ “large” animals attaining 317 lbs
¾ among most photogenic of pelagic fishes Sexual dimorphism of the pectoral girdle in ‘large’ opah:
male female
“deep, abrupt angle” “gradual rounding”
“thick, concave” “narrow, convex”
male female
Images by Don Hawn UFA sampling, opah
116 600 114
112 500 N =30,370 110
108 400
106 300 104 equency
Weight (lbs) 102
Fr 200 100
98 100
96
0 94 50 100 150 200 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 Weight (lbs) Year
(Data courtesy FMEP, NMFS Honolulu Laboratory) UFA sampling, opah Age & Growth, Opah
¾ Relatively clear annuli in cross- sections of 2nd ray of dorsal fin
¾ Assuming annuli are formed annually, fish are estimated between 1+ to 6+ years (2 to 7 annuli) Spatial distribution patterns, preferred habitat, faunal associations and trophic relationships
¾ Capture depth information collected from vessels of opportunity: F/V Tucana (Apr ’02) F/V Sea Pearl (Nov ’02) F/V Kelly Ann (Mar ’03) F/V Sea Pearl (Jul ’03) ¾ Diet studies 30 – 107 cm FL (M = 64 cm) 97 - 116 cm FL (M = 106 cm) ¾ 99.03% of opah taken on 2.5
“deep” sets 2.0 2001 2000 1.5 1999 1998 UE (per set) 1.0 1997 ¾ But opah also taken at 0.5 Opah CP surface as evidenced in "All sets" high seas driftnet fisheries 0.0 3.0 catches – peaks in June- 2.5
August 2.0
1.5 (per DEEP set) E
U 1.0 P
¾ Catches of opah in the 0.5 "Deep sets only" Opah C 0.0 Hawaii longline fishery peak 25 'High seas driftnet' during August-October, 20 BUT … 000 tans) 1990 50, 15 1991 (per 10
5 ftnet CPUE
Dri 0 123456789101112
Month Opah landings at UFA, 2000-01
1600 1400 ¾ Aug-Oct are also 1200
Fish 1000 800 periods when 600 400 Number of smallest fish are 200 0 3.0 )
landed – effort $ 2.5 (US
distribution? ice 2.0 r
1.5
erage P 1.0 v A 0.5
¾ Size (especially 110
105 when small) (lbs)
ight 100 e tends to be 95 age W r
e 90 v
reflected in price A 85 -00 -00 -00 -01 -01 -01 -00 -00 -01 -01 -00 -00 -00 -01 -01 -01 -00 -01 r r r r y y v-00 v-01 g g a a p p a a u u Jul Jul A Oct-00 A Oct-01 Jan Jan Feb Jun Feb Jun M M Dec-00 Dec-01 Sep Sep No No A A M M Time (mth-yr) UH Requirements For Vertebrate Animal Use
(http://www.hawaii.edu/ansc/IACUC/index.html)
¾ Do fish feel Pain – yes/no?
¾ The Institutional Animal Care & Use Committee (IACUC) - 2003 Vertebrate Animal Use Protocol Form
¾ GUIDELINES FOR USE OF FISHES IN FIELD RESEARCH American Society of Ichthyologists and Herpetologists (ASIH), American Fisheries Society (AFS), American Institute of Fisheries Research Biologists (AIFRB), from Fisheries , Vol. 13, No. 2, p. 16-23, 1988
¾ Regulations for Care and Use of Vertebrate Animals for Research (WebCT site) Opah movement in the central North Pacific (PAT tags)
♂ ♀ Trip 4 (Jul ’03)
Trip 3 (Mar ’03)
Trip 2 (Nov ’02)
Trip 1 (Apr ’02) Core temperatures (°C) of opah monchong
Opah NMean± SDMinMax All 38 17.7 4.5 7.8 26.4 Alive 9(24%) 21.6 4.0 15.3 26.4 Dead 29(76%) 16.5 4.1 7.8 25.9 Monchong NMean± SDMinMax All 98 18.0 3.4 9.5 25.0 Alive 72(73%) 17.9 3.2 11.1 24.6 Dead 26(27%) 18.1 3.9 9.5 25.0
Deep tuna baskets 0
100 )
ers 200
300
Depth (met 400
500
600 Eye muscle, n:18 = 3.1°C (5.6°F) 5 1015202530 Time (hours) Project status: ¾ Progressing: some facets of study faster than others
¾ Winter ’04 sampling trip
¾ Data/sample collections and analyses continue Questions?