Search for: All records

Haplosclerid sponges (Porifera: Demospongiae: Heteroscleromorpha), and particularly the family Chalinidae, are notoriously difficult to identify through taxonomic methods alone. Here we use an integrative approach to confirm the identification and report both polymorphic characters and different morphotypes exhibited from a recruitment stage that complicate identification of introduced haplosclerid species Haliclona (Soestella) caerulea and Gelliodes conulosa sp. nov. in Hawaiʻi. Using these same methods, we also describe three new species Haliclona (Gellius) pahua sp. nov., Haliclona (Reniera) kahoe sp. nov., Haliclona (Rhizoniera) loe sp. nov. from our collections in Kāne‘ohe Bay. Using a combination of mitochondrial and ribosomal RNA sequences, we compile a phylogeny that is consistent with previous molecular work but is at odds with the morphological characters used to classify species belonging to Chalinidae and Niphatidae families within Haplosclerida. Although shared morphological traits were distributed across taxa throughout the tree, both mitochondrial and ribosomal RNA sequences were diagnostic, with an average of at least 3 % sequence divergence among species and their closest relative. This study highlights both the use of standardized Autonomous Reef Monitoring Structures (ARMS) to access the hidden diversity of haplosclerid sponges, and the potential for competition between these introduced and newly described and potentially endemic species.   

Climate-driven warming and changes in major ocean currents enable poleward larval transport and range expansions of many marine species. Here, we report the population genetic structure of the gastropodKelletia kelletii, a commercial fisheries species and subtidal predator with top-down food web effects, whose populations have recently undergone climate-driven northward range expansion. We used reduced representation genomic sequencing (RAD-seq) to genotype 598 adults from 13 locations spanning approximately 800 km across the historical and expanded range of this species. Analyses of 40747 single nucleotide polymorphisms (SNPs) showed evidence for long-distance dispersal ofK. kelletiilarvae from a central historical range site (Point Loma, CA, USA) hundreds of km into the expanded northern range (Big Creek, CA), which seems most likely to result from transport during an El Niño-Southern Oscillation (ENSO) event rather than consistent on-going gene flow. Furthermore, the high genetic differentiation among some sampled expanded-range populations and their close genetic proximity with distinct populations from the historical range suggested multiple origins of the expanded-range populations. Given that the frequency and magnitude of ENSO events are predicted to increase with climate change, understanding the factors driving changes in population connectivity is crucial for establishing effective management strategies to ensure the persistence of this and other economically and ecologically important species. 

Many marine animals have a biphasic life cycle in which demersal adults spawn pelagic larvae with high dispersal potential. An understanding of the spatial and temporal patterns of larval dispersal is critical for describing connectivity and local retention. Existing tools in oceanography, genetics, and ecology can each reveal only part of the overall pattern of larval dispersal. We combined insights from a coupled physical-biological model, parentage analyses, and field surveys to span larval dispersal pathways, endpoints, and recruitment of the convict surgeonfish Acanthurus triostegus . Our primary study region was the windward coast of O‘ahu, Hawai‘i. A high abundance of juvenile A . triostegus occurred along the windward coast, with the highest abundance inside Kāne‘ohe Bay. The output from our numerical model showed that larval release location accounted for most of the variation in simulated settlement. Seasonal variation in settlement probability was apparent, and patterns observed in model simulations aligned with in situ observations of recruitment. The bay acted as a partial retention zone, with larvae that were released within or entering the bay having a much higher probability of settlement. Genetic parentage analyses aligned with larval transport modeling results, indicating self-recruitment of A . triostegus within the bay as well as recruitment into the bay from sites outside. We conclude that Kāne‘ohe Bay retains reef fish larvae and promotes settlement based on concordant results from numerical models, parentage analyses, and field observations. Such interdisciplinary approaches provide details of larval dispersal and recruitment heretofore only partially revealed.