Reduced exploitation is associated with an altered sex ratio and larger length at maturity in southwest Pacific (east Australian) Pomatomus saltatrix.

Authors:
James A Smith
James A Smith
University of Virginia
John Stewart
John Stewart
Wake Forest School of Medicine
United States
Julian M Hughes
Julian M Hughes
Sydney Institute of Marine Science
Mosman | Australia
Iain M Suthers
Iain M Suthers
School of Biological

Mar Environ Res 2019 May 3;147:72-79. Epub 2019 Mar 3.

Evolution and Ecology Research Centre, University of New South Wales, Sydney, NSW, 2052, Australia; Sydney Institute of Marine Science, Building 19, Chowder Bay Road, Mosman, NSW, 2088, Australia.

Pomatomus saltatrix is an important recreational fishing species with seven major populations worldwide. The reproductive biology of the southwest Pacific Ocean (east Australian) population is uncertain, with both an extended spawning and multiple spawning periods previously hypothesised. Here we demonstrate an altered sex ratio biased towards females and a larger length at 50% maturity (L) compared to those recorded for the population 40 years ago, before comprehensive management strategies were implemented. We also report a second, previously undescribed, late-summer spawning event which was identified by analysing patterns in a gonadosomatic index across the whole population and an historical larval fish database. P. saltatrix are capable of spawning multiple times per season with estimates of batch fecundity ranging from 99,488 to 1,424,425 eggs per fish. When combined with the length frequency distribution of the population, the majority of eggs (64%) were shown to be produced by fish ≤40 cm fork length (FL). L was estimated at 30.2 and 31.5 cm FL for male and female P. saltatrix respectively, 4 cm larger than 40 years ago. The sex ratio of the population was found to have significantly shifted over the last 40 years from an equal sex ratio to a female dominated population (1.58 females:1 male). These dramatic alterations to the sex ratio and L highlights the value of monitoring the reproductive biology of exploited fish populations to ensure that management plans remain appropriate.

Download full-text PDF

Source
https://linkinghub.elsevier.com/retrieve/pii/S01411136183089
Publisher Site
http://dx.doi.org/10.1016/j.marenvres.2019.02.012DOI Listing
May 2019
4 Reads

Publication Analysis

Top Keywords

sex ratio
20
southwest pacific
8
larger length
8
east australian
8
pomatomus saltatrix
8
spawning multiple
8
reproductive biology
8
years ago
8
altered sex
8
population
6
ratio
5
sex
5
female dominated
4
population historical
4
historical larval
4
gonadosomatic population
4
patterns gonadosomatic
4
fish
4
analysing patterns
4
dominated population
4

Similar Publications