Modeled Population Connectivity across the Hawaiian Archipelago

Abstract

We present the first comprehensive estimate of connectivity of passive pelagic particles released from coral reef habitat throughout the Hawaiian Archipelago. Potential connectivity is calculated using a Lagrangian particle transport model coupled offline with currents generated by an oceanographic circulation model, MITgcm. The connectivity matrices show a surprising degree of self-recruitment and directional dispersal towards the northwest, from the Main Hawaiian Islands (MHI) to the northwestern Hawaiian Islands (NWHI). We identify three predicted connectivity breaks in the archipelago, that is, areas in the mid and northern part of the archipelago that have limited connections with surrounding islands and reefs. Predicted regions of limited connectivity generally match observed patterns of genetic structure reported for coral reef species in the uninhabited NWHI, but multiple genetic breaks observed in the inhabited MHI are not explained by passive dispersal. The better congruence in our modeling results based on physical transport of passive particles in the low-lying atolls of the uninhabited NWHI, but not in the anthropogenically impacted high islands of the MHI begs the question: what ultimately controls connectivity in this system?

Seascape models reveal places to focus coastal fisheries management

“…The next most important criteria to consider is larval connectivity to ensure that adequate portions of larvae are exported into fished areas (Green et al 2015). While larval transport modeling is still in its infancy, recent work has modeled potential connectivity based on oceanographic circulation in the Hawaiian islands and identified potential larval sources and sinks at 4 km 2 resolution (Wren et al 2016). Places that are capable of supporting high spawner biomass, which are also important larval source areas for connected reefs, would be good candidates for enhanced fishery management or protection.…”

Genetic population structure of the convict surgeonfish Acanthurus triostegus: a phylogeographic reassessment across its range

“…The finding of isolation‐by‐distance is not surprising given the sample sites of this study spread across a geographic distance of more than 28,000 km that is characterised by discontinuous reef habitats. Notably, pairwise comparisons with Hawaii and Johnston Islands populations exhibit higher Φ ST values even at a relatively short distance (Figure and Table ), possibly due to self‐recruitment presumed to occur at these sites (Wren et al ., ). The spatial arrangement of samples sites in the MDS plot correspond to the genetic similarity of sample sites, providing further evidence of isolation‐by‐distance (Figure ).…”

Vagrancy in paradise: documentation of the chevron butterflyfish Chaetodon trifascialis in Kaneohe Bay, Oahu, Hawaiian islands

“…comm.). Given known larval connectivity pathways, the specimen of C. trifascialis was most likely a vagrant species from Johnston Atoll (Kobayashi, 2006;Wren et al, 2016).…”

“…In the Hawaiian archipelago, larval connectivity from Johnston Atoll represents the most likely source for periodic colonization of reef fauna, such as butterflyfish (family: Chaetodontidae) and stony corals of family Acroporidae (Kobayashi, 2006;Wren et al, 2016). The overlap in butterflyfish species composition between the Hawaiian archipelago and Johnston Atoll is nearly Fig.…”