西部和中部北太平洋海域灰鯖鮫

1、Age and growth analysis of the shortfin mako, Isurus oxyrinchus, in the western and central North Pacific Ocean西部和中部北太平洋海域灰鯖鮫之年齡成長分析Yasuko Semba & Hideki Nakano & Ichiro AokiEnviron Biol Fish (2009) 84:377391speaker：陳怡婷Shortfin Mako Kingdom AnimaliaPhylum ChordataClass ChondrichthyesSubclass Elasmob

2、ranchiiOrder LamniformesFamily LamnidaeGenus IsurusSpecies oxyrinchus中文名 灰鯖鮫圖片來源 .tw/chi/showpic.php?science=Isurus%20oxyrinchus資料來源 .tw/chi/newsearch/search.asp?search=order00 IntroductionBiology Habitats : Ocean、Deep Sea、Coastal Habitats Depth : 0 - 740 M Max Lenth : 400 cm Size at birth estimated

3、 to be about 60-70 cm in TL. Ovoviviparous, with a uterine cannibal. 高級消費著消費者生產者.tw/Photos/ThumbnailsSummary.php?ID=752 r-organisms K-organisms short-lived long-lived small adult size large adult sizeweak strong or well-protected waste a lot of energy energy efficient have large litters have small l

4、itters reproduce at an early age reproduce at a late age fast maturation slow maturation strong sex drive weak sex drive small size at birth large size at birth Characteristic Wide distribution, and prefers temperatures of 17 to 22C. (Casey and Kohler 1992)Migration Sexual/ontogenetic stage segregat

5、ionDistribution 資料來源 http:/receive.phpSustainable Development The recent and rapid collapse of large predatory fish populations is a global concern (Myers and Worm 2003, 2005).Information on life history parameters derived from age and growth analyses plays an integral role. Age determination is an

6、important component of population analyses.In addition, the growth curves generated in this study were compared to those for populations in other geographic regions.Materials and methodsSample collectionSampling period : 19922005 by the Japanese research vessels and tuna longline training vessels.Sa

7、mpling amount : 275 individuals (128 males and 147 females).Sampling site : western and central North Pacific Ocean.Fig. 1 Sampling locations for the shortfin mako (Isurus oxyrinchus) in the western and central North Pacific Ocean. Each point denotes a position where samples were collected.Fig. 2 Le

8、ngth frequency of the specimen used for the analysis/./Images/test PCL ( cm )TL ( mm )DL ( mm )FL ( mm )DL, TL, FL with PCLPCL : 57.2 to 186.5 cmStepSex determinationMeasure PCLExcise the vertebral column above the gill slitsFroze the vertebral column at 40CVertebral processingBoil the vertebraeStor

9、e it in 70% ethanolCut off a single centrumSoak it in 6N NaOHScrub it with apolishing buffEach centrum is cutinto two longitudinal sections after dryingThe halfcut centra with the focus were used for analysis after washing away the bone particle and drying for 1 dayFour techniques to enhance vertebr

10、al growth bandsshadowing (half-cut centra; Francis and Maolagin 2000)alizarin staining (section;Berry et al. 1977) silver nitrate staining (whole centra; Stevens 1975)soft X-radiography (whole or half-cut centra; Cailliet et al. 1983)Method of age determinationshadowingalizarin stainingsilver nitrat

11、e stainingsoft X-radiographyVertebral half-cut centrasagittal sectionwhole centrawhole or half-cut centraGrowth bandsconvexconcavelightly stained (opaque)deeply stained (translucent)translucent regionopaque regionSpending timeshorttestlongerlongershorteranalysismore precision and clarityless informa

12、tionless informationoverestimationThe shadowing methodSimplicityVisual clarityRelative abundance of information amountLess time-consuming processFig. 3 Half of a vertebral centrum with lateral illumination from fiber-optic sources. The triangles indicate a convex structure or growth band. This examp

13、le is from a 137 cm PCL female, with a vertebral centrum radius of 9.5 cm, and an estimated age of 4.6 yearsAge determination In this way, the convex and concave structures were observed as light and dark regions, respectively. These structures correspond to the opaque (convex) and translucent (conc

14、ave) regions observed in the sagittal section.The vertebrae of neonates, which displayed only a birthmark, were excluded from this analysis.CR with PCLThe centrum radius (CR) is the distance from the focus to the edge of the centrum perpendicular to the direction of the cutting plane. The CR was mea

15、sured to the nearest 0.01 mmCRFig. 6 Age-bias plot of 275 shortfin mako vertebral counts from two independent readings by the first author. The open and solid mark indicate the observed counts and the mean counts assigned by the second count for all fish which was assigned a given count in the first

16、 count up to 12, respectively. The vertical bars for the solid mark up to the first count of 11 indicate the 95% confidence interval. The one to one equivalence line is also represented.PA= No. agreed/No. read*100Assuming that annuli (convex structures) are formed soon before or after 1 December, ag

17、e in years was calculated as follows:x = the number of convex structurey = the month when the individual was caught (1y12).Lt = PCL at time t (cm)L0 = size at birth (cm)(74 cm TL) (Joung and Hsu 2005)L =asymptotic length (cm) K = brody growth constant (year1).VBGE with size at birthResultsMale : 532

18、40 cm (PCL)Female : 57300cm (PCL) the allometric equation for regression analysisAkaikes Information CriterionAIC = n ln(MSE) + 2Kmodel N (no bandperiodicity) : 312.44model A (annual periodicity) : 271.89model B (biannual periodicity) : 316.24The estimated growth equationst = age (years)The estimate

19、d S.E. of L for females was larger than that for males, whileS. E. of K for males was larger than for femalesDiscussionGrowth Fig. 7 Estimated von Bertalanffy growth curves for female and male shortfin mako in the western and central North Pacific OceanPCL : 308 cm FL : 370 cmGrowth band formationCo

20、nvex dominant in the winter and concave dominant in the summer.Neonates captured in May and June suggested that the formation of the first convex concentric structure (birthmark) occurs after parturition.Branstetter (1987)We determined that the growth increment between the birthmark and the second annulus is approximately 7 months.Fig. 8 Comparison of growth curves to those reported in previous studies for a males and b females. The curves reported by Pratt and Casey (1983) were