The NOAA IR serves as an archival repository of NOAA-published products including scientific findings, journal articles, guidelines, recommendations, or other information authored or co-authored by NOAA or funded partners.
As a repository, the NOAA IR retains documents in their original published format to ensure public access to scientific information.
i
Sex ratios in blue whales from conception onward: effects of space, time, and body size
-
2020
-
Source: Marine Mammal Science, 37(1), 290-313
[PDF-3.49 MB]
Details:
-
Journal Title:Marine Mammal Science
-
Personal Author:
-
NOAA Program & Office:
-
Description:Deviations from equal sex ratios in mammals can reveal insights into sex‐specific growth, survival, movements, and behavior. We assessed blue whale (Balaenoptera musculus) sex ratios based on 21,542 fetal and 311,901 whaling records, finding that males were slightly but significantly more common than females (51.3% fetal, 52.1% postnatal). Antarctic catches shifted from 52.4% male before 1951 to 48.0% male thereafter, even though larger females were preferentially targeted by whalers and should have declined. The southernmost land stations caught more males than those in southern Africa, and at land stations, sex ratios shifted subtly over the course of a year. Pelagic catches demonstrated spatial structure in sex ratios, including more males being caught in the Ross Sea. In utero, the smallest females were often misidentified as males, and there was some evidence for higher prenatal male mortality. Once born, medium‐sized blue whales within each region were more often male, while the longest were nearly all female; explained entirely by females growing faster and reaching longer sizes. Overall, though, sex ratios are remarkably close to equality across time, space, and length; with any deviations best explained by faster female growth and size‐selective whaling.
-
Keywords:
-
Source:Marine Mammal Science, 37(1), 290-313
-
DOI:
-
ISSN:0824-0469;1748-7692;
-
Format:
-
Publisher:
-
Document Type:
-
Rights Information:Accepted Manuscript
-
Compliance:Library
-
Main Document Checksum:
-
Download URL:
-
File Type:
