Do protected areas mitigate the effects of fisheries-induced evolution on parental care behaviour of a teleost fish?

Abstract

While the use of aquatic protected areas that exclude angling might be considered an evolutionarily enlightened management approach to dealing with fisheries-induced evolution (FIE), there is little empirical data on the effectiveness of this approach at maintaining the diversity of phenotypic traits within protected areas. In species with paternal care, including largemouth bass (Micropterus salmoides), active nest-guarding and aggression towards potential brood predators by males may render these individuals particularly vulnerable to capture by angling because of increased propensity to attack fishing lures/bait near their nests. Relative levels of aggression by these males during the parental care period correlates with their vulnerability to angling year round. Selective removal of more aggressive individuals by anglers should drive population-average phenotypes towards lower levels of aggression. To assess the effectiveness of protected areas at mitigating FIE, the parental care behaviours of wild, free-swimming male bass were compared during the early nesting period for bass within and outside protected areas in a lake in eastern Ontario. Nesting males within long-standing aquatic protected areas closed to fishing for >70 years were more aggressive towards bluegill sunfish (Lepomis macrochirus), a potential nest predator, and patrolled larger areas around their nests compared with bass outside of sanctuaries. Males within protected areas were also more likely to strike at artificial fishing lures and were more prone to capture during angling events. Collectively, the findings suggest that the establishment of protected areas may promote phenotypic diversity such as more attentive and vigorous parental care, relative to areas open to angling. The extent to which this phenomenon occurs in other species and systems is likely to depend on the reproductive strategies of fish and their spatial ecology compared with protected area boundaries, and habitat quality within protected areas.