Harvesting changes mating behaviour in European lobster

Area of Science:

• Ecology
• Evolutionary Biology
• Fisheries Science

Background:

• Harvesting wild populations can alter mating patterns and sexual selection.
• Understanding the interplay between selective fishing and mating systems is crucial for predicting fisheries-induced evolution.
• Limited empirical data exists on how fishing affects sexual selection dynamics in exploited species.

Purpose of the Study:

• To compare mating patterns of European lobster (Homarus gammarus) in a fished area versus a marine reserve.
• To investigate the effects of size- and sex-specific fishing mortality on sexual selection.
• To assess the impact of fishing on the evolution of body and claw size in male lobsters.

Main Methods:

• Genetic parentage assignment was used to analyze mating patterns.
• Comparison of mating patterns between a lobster reserve and a fished area in southern Norway.
• Analysis of male and female body size differences and their relation to mating success.

Main Results:

• Female European lobsters preferred larger males, with a greater size difference observed in the reserve.
• Sexual selection positively influenced male body and claw size in the reserve.
• Sexual selection on male size was non-significant in the fished area, indicating reduced selection pressure.

Conclusions:

• Size truncation of males by fishing reduces the effectiveness of sexual selection.
• Targeting large, reproductively successful males in fisheries accelerates fisheries-induced evolution towards smaller body size.
• Fishing regulations need to consider the impact on sexual selection to manage exploited populations sustainably.