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Mollet H.F. and G. M. Cailliet
Preliminary demographic analysis of the shortfin mako shark, Isurus oxyrinchus Mollet H.F. and G. M. Cailliet
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Contrasting VBGF and Reproductive Parameters for the Shortfin Mako Pratt and Casey 1983 vs. Cailliet et al. 1983
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Age at Maturity of Female Shortfin Mako (when 10 and 90% are mature) 1
Age at Maturity of Female Shortfin Mako (when 10 and 90% are mature) 1. L (t) = ( ) e( t), Pratt and Casey L (t) = ( ) e( t), Cailliet et al. 1983
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Observed and Calculated (from VBGF) Growth Rates for the Shortfin Mako 1. L (t) = ( ) e ( t), Pratt and Casey L (t) = ( ) e ( t), Cailliet et al. 1983
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Band-Count and Capture-Date Frequency Histograms
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Check on Seasonality of #Bands (based on preliminary band count data sheets)
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Growth Rates of Southern California Makos from Modes of Length-Frequency Histograms
~50 cm/yr at age 0.25 yr ~34 cm/yr at age 1 yr Fall data Cailliet et al assuming 2 bands/year. ~45 cm/yr at age 0.67 yr ~30 cm/yr at age 1.67 yr O'Brian and Sunada 1994, modes at AL = 42 and 53 cm (TL = 122 and 152 cm) from 2+ and 3+ year old makos, respectively. ~60 cm/yr at age 0.25 yr ~30 cm/yr at age 1.0 yr cm/yr at age 2.0 yr Hanan et al. 1993, modes at AL = 34, 44, and 54 cm (TL = 100, 130, and cm) from 0.5, 1.5 and 2.5 year old makos, respectively.
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Catch Curves Estimation of Survival from Age Composition (Ricker 1977, Krebs 1989)
Right limb is a survivorship curve that is both age-specific and time-specific if the following assumptions are met: Survival rate is uniform with age Survival rate is uniform with time Sample taken randomly from age groups involved Recruitment is constant for all age groups If these 4 assumptions are violated, the right limb of the catch curve will often not be a straight line.
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Catch Curve of Female Shortfin Makos
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Catch Curve for Exp. Drift Longline Fishery in Southern California during O'Brian and Sunada 1994
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Catch Curve for Makos taken by Japanese Longliners off the eastern coast of Australia(Stevens 1992) can add n=98 females, Z = 0.61 but # to small to derive meaningful catch curve. Could try smoothing.
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Catch Curve for Shortfin Mako off East Northland and Bay of Plenty, New Zealand (Saul and Holdsworth 1992) (females extracted and large females from off-shore added)
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Catch Curve for Female Shortfin Mako from western North Atlantic, n = 1113 (Casey and Kohler 1992) Z= 0.70, too large! but why,
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Catch Curve for Shortfin Mako off South-Eastern Australia 1961-90 (Pepperell 1992)
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D? Mejuto for years 1983 and 1984 combinend female data for the 2 years then calculatet age_FL. Was done later!
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Summary of Z's from Catch Curve for Female Shortfin Makos
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Parameters for Demographic Analysis
1. Length at Age (VBGF). 2. Estimate of natural mortality (M) Hoenig 1983 (requires max. age estimate, we used 7 ln2/k = 23.9 years (k = year-1). Pauly 1974 (requires max. size = 3.73 m TL, VBGF k = year-1, and water temperature T = 20 C. 3. Estimate of fishing mortality (F) or total mortality (Z = M + F); we used catch-curve derived Z. 4. Natality, to be discussed next.
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Effective Natality vs. TL 10, 50, 90% mature at TL = 2. 60, 2. 72, 2
Effective Natality vs. TL 10, 50, 90% mature at TL = 2.60, 2.72, 2.85 m) mx(TL) = (1/4) TL2.66 e( TL)/(1+e( TL));
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Effective Natality vs. Age 10, 50, 90% mature at age 4. 8, 5. 4, 6
Effective Natality vs. Age 10, 50, 90% mature at age 4.8, 5.4, 6.1yr mx = (1/4) TL e( TL)/(1+e( TL)); with TL = ( )e( age)
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Life-History Table of Isurus oxyrinchus Input: VBGF, Z = 0
Life-History Table of Isurus oxyrinchus Input: VBGF, Z = 0.30 year-1, mx = effective natality Output: Ro = 2.0, G = 9.0 year, r = year-1, er = 1.08
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Life-History Table of Isurus oxyrinchus Input: VBGF, Z = 0
Life-History Table of Isurus oxyrinchus Input: VBGF, Z = 0.34 year-1, mx = effective natality Output: Ro = 1.08, G = 9.72 year, r = year-1, er = 1.01
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Life History Parameters for Isurus oxyrinchus (F starts at age 0)
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Life History Parameters for Isurus oxyrinchus First year mortality 2x subsequent mortalities
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Life History Parameters for Isurus oxyrinchus using 3-Year Reproductive Cycle (F= 0.05 and 0.10 year-1start at age 0)
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Life History Parameters for Isurus oxyrinchus (F= 0. 05 and 0
Life History Parameters for Isurus oxyrinchus (F= 0.05 and 0.10 year-1start at age 0)
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Life History Parameters for Isurus oxyrinchus M1 = 2 x M1+j
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Life History Parameters for Isurus oxyrinchus (F= 0. 05 and 0
Life History Parameters for Isurus oxyrinchus (F= 0.05 and 0.10 year-1start at age 0)
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Life History Parameters for Sharks (Adding to Cortés 1995 and 1996)
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Finite Rate of Population Change (er) vs. Z (Southern Hemisphere vs
Finite Rate of Population Change (er) vs. Z (Southern Hemisphere vs. Western North Atlantic Age at Maturity)
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Finite Population Rate Decrease (er) vs
Finite Population Rate Decrease (er) vs. Z Base calculation with observed fecundity and southern hemisphere age at maturity
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