Lack of genetic divergence in capelin (Mallotusvillosus) spawning at beach versus subtidal habitats in coastal embayments of Newfoundland

Abstract

Capelin (Mallotus villosus (Müller, 1776)), a focal forage fish in the north Atlantic, spawn on both beach and demersal (deep-water) sites throughout their circumpolar distribution. Although these habitats rarely occur in close proximity, demersal spawning sites within 4 km of beach spawning sites (subtidal) have recently been discovered in two coastal embayments in Newfoundland, Canada. The physical environment differs considerably between beach and subtidal spawning sites, creating the potential for local adaptation and genetic divergence of capelin from the two habitats, but this has never been investigated on a fine spatial scale. We use eight microsatellite loci to test for genetic divergence between capelin spawning at beach and subtidal sites within these two coastal regions in Newfoundland. We found no genetic differentiation between fish spawning at beach and subtidal sites or between the two regions. The results from this fine-scale study are in agreement with the lack of habitat-based structure reported in other studies examining beach and demersal sites separated by a larger geographic area. We suggest that instead of showing site fidelity and local adaptation, the facultative use of alternate spawning habitats may be a more successful strategy in an unpredictable environment.

Egg cannibalism in capelin Mallotus villosus at beach and deep‐water spawning habitats in the north‐west Atlantic Ocean

“…, ), with egg cannibalism having a higher selective advantage in beach spawning capelin. For Newfoundland capelin, however, parity in coastal beach and deep‐water spawners has not been quantified and spawners in both habitats appear to be part of the same population (Kenchington et al ., ; Penton et al ., ; Penton & Davoren, ). This being the case, one might predict higher mortality of beach spawning fish, due to the increased probability of becoming stranded when depositing gametes above the intertidal zone (Templeman, ), with a lower selective advantage of egg cannibalism.…”

A novel sperm adaptation to evolutionary constraints on reproduction: Pre‐ejaculatory sperm activation in the beach spawning capelin (Osmeridae)

“…Around the island of Newfoundland M. villosus spawn predominantly on beaches, but also on the seafloor in nearshore areas (Nakashima & Taggart, ). These groups are not genetically distinct populations (Penton, McFarlane, Spice, Docker, & Davoren, ), but rather spawning choices attributed to temperature by some authors (Davoren, ). Our results add to the difficulties in reproductive success faced by subtidal spawning M. villosus as predicted by Nakashima and Wheeler ().…”

Endurance rivalry in capelin: insights from semen quality and regeneration

“…4 Methodology Among male variation in semen quality -spawning beach surveys Spawning male capelin were captured during June and July 2023, using a dip net on three beaches of the Avalon Peninsula, Newfoundland, Canada: Middle Cove Beach (47° 39' 2.75" N, 52° 41' 45.24" W) on 29 th June; 2 nd , 4 th , 6 th ,10 th , 12 th and 14 th July, Bellevue Beach (47° 38' 9.28" N, 53° 46' 51.09" W) on 7 th , 8 th , 9 th July, and Holyrood Beach (47° 23' 21.8" N, 53° 07' 34.5" W) on 21 st July. Fish from these beaches are thought to be from the same population (Dodson et al, 1991;Penton et al, 2014).…”