Fish reproductive-energy output increases disproportionately with body size

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Science  11 May 2018:
Vol. 360, Issue 6389, pp. 642-645
DOI: 10.1126/science.aao6868
  • Fig. 1 Hyperallometric scaling of reproductive-energy output.

    (A) Hyperallometric (β1 = 1.33, solid red curve; see table S7) and isometric mass scaling (β1 = 1, dashed blue curve) relationships for the Atlantic cod, G. morhua. Fish sizes span more than one order of magnitude in mass (2 versus 30 kg). (B) Total population-level biomass (Embedded Image) required to produce the same reproductive output (Embedded Image, in megajoules) for two populations of fish with hyperallometric scaling that differ in the mass of the individual fish, where i is individuals: The standing-biomass ratio differs by ~2.5-fold (that is, 74 versus 30 kg) from the larger individual to the population with smaller individuals. [Illustration credit: Diane Rome Peebles]

  • Fig. 2 Scaling relationships of fish reproductive traits.

    (A) Relationship between fecundity and female mass. Red circles represent individual clutches. (B) Mass scaling of egg volume. (C) Volume scaling of egg energy content. Green triangles represent independent observations [egg volume and egg energy content in (B) and (C), respectively]. The y axes were corrected for species-specific deviations on the intercept and scaling exponent, which were obtained using Bayesian phylogenetic hierarchical modeling. Equations in the top-left corners depict average fixed effects; 95% CI is Bayesian credible interval for the scaling exponent; n is the total number of observations. Dashed black lines depict average model fits. Species and family names and the data summary and contributions for the three models [shown in (A), (B), and (C)] (8) are provided in tables S3 to S5, respectively. Note both axes are logged.

  • Fig. 3 Species-specific reproductive-energy mass-scaling exponents.

    Average exponents and 95% CIs (shown by horizontal bars) for 342 species were obtained by combining species-specific (when available) posterior estimates from models in Fig. 2, A to C (8). If a species was not present in a given data set, we used the population-level fixed-effect posterior estimates for the model in question. The dashed line represents the reproductive isometry reference point; the dotted line represents the average fixed-effect exponent value. Red circles and green triangles represent species whose scaling exponents are greater than and less than 1, respectively. Fish silhouettes depict the major clades represented in this figure. See table S7 for species and family names and estimates of reproductive energy–output slopes.

Supplementary Materials

  • Fish reproductive-energy output increases disproportionately with body size

    Diego R. Barneche, D. Ross Robertson, Craig R. White, Dustin J. Marshall

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods 
    • Fig. S1
    • Tables S1 to S8
    • References 

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