Differences in prevalence of multiple paternity in the spiny spider crabMaja brachydactylain two localities that differ in female fecundity, fishing intensity, and management measures

E Rodríguez-Pena,L Fernández,P Verísimo,O Tully,A Martínez-Lage

doi:10.1093/icesjms/fsab060

E Rodríguez-Pena, L Fernández + Show 3 more

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https://doi.org/10.1093/icesjms/fsab060

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Abstract

AbstractMany marine species are under high fishing pressure, which can cause alterations in their mating systems and the structure of their populations. The spiny spider crab Maja brachydactyla is a commercial decapod on the east Atlantic coast. In Galicia, the most exploited region in Spain, the landing of ovigerous females is prohibited, favouring exploitation focused on males. The removal of males, especially the largest ones, may lead to sperm limitation and a reduction in the average size over generations. In these cases, polyandry can work as a mechanism to protect females against sperm limitation and to increase genetic diversity and effective population size. This study analyses the multiple paternity in M. brachydactyla in two localities that differ in female fecundity, fishing intensity, and management measures. Our results showed multiple paternity in this species for the first time, with a moderate bias between sires. However, the frequency of multiple paternity was almost seven times higher in the intensely exploited Golfo Ártabro (NW Spain; 69%) than in Carna (W Ireland; 10%), where exploitation levels and female fecundity are lower.

Highlights

For an adequate management of commercial species, a detailed understanding of their mating systems and biological traits, such as size and age distributions and the intensity of sexual selection, is essential (Emlen and Oring, 1977)
By including the nine loci the exclusion probability increases slightly, this does not compensate for the large increase in costs that would result from tripling the number of loci analysed
The prevalence of multiple paternity is higher in species without specialized sperm storage structures, such as carideans and anomurans

Summary

Introduction

For an adequate management of commercial species, a detailed understanding of their mating systems and biological traits, such as size and age distributions and the intensity of sexual selection, is essential (Emlen and Oring, 1977). When management measures are aimed at protecting particular sizes or a specific sex, these disturbances are accentuated and an alteration of the structure of the population and a reduction of reproductive potential may occur. This is the case of several crustacean fisheries regulated by minimum landing sizes and prohibitions on the landing of ovigerous females. The removal of the largest males will force many females to copulate with

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