Historical trends of sperm whale (Physeter macrocephalus) distribution in the Phoenix Archipelago

The Phoenix Archipelago in the Central Pacific is situated in what was once one of the most productive areas for capturing sperm whales (Physeter macrocephalus). These whales were the focal targets of American offshore whalers in the mid-19th century along the equator, an area known as the “on-the-line” whaling grounds. Now, as large-scale Marine Protected Areas (MPAs) have provided protection for marine mammals and their food sources, it is important to have a solid understanding of historical baselines so recovery distributions can be compared with pre-whaling distributions. The Phoenix Islands archipelago contains two large MPAs: the Phoenix Islands Protected Area (PIPA), established by Kiribati in 2008, and the Howland/Baker unit of the Pacific Remote Islands Marine National Monument (PRIMNM), established by the United States in 2009. Using historic whaling records from American whaling vessels operated through the wider Phoenix Archipelago region, we reconstructed information about the presence and distribution of P. microcephalus throughout the 1800s within and around PIPA and the Howland/Baker units of the PRIMNM. Historical data analyzed using ArcGIS showed that sperm whales were present year-round within the study area, which is consistent with 20th century records from the Ocean Biogeographic Information System (OBIS). A Getis Ord Gi∗ hotspot analysis also revealed sighting hotspots within PIPA and near Howland and Baker, suggesting that these two areas may be of long-term ecological importance to sperm whales in the central Pacific. The New England whaling fleet ceased whaling effort in the central Pacific in the late 1800s, and publicly available records since that time are scarce. There has been no modern systematic whale survey ever conducted within the Phoenix Archipelago, though anecdotal accounts and sightings have been compiled over the years. These intermittent accounts suggest that though whale populations have not recovered to pre-whaling baselines, large-scale MPAs may play a role in helping to foster a resurgence of marine mammal populations. As the network of large-scale MPAs continue to grow as part of the commitment to ocean conservation set forth by UNESCO, IUCN, and the UN Decade for Ocean Science, historical baselines will be critical as a “yardstick” to measure population resurgence success for each MPA, and for populations overall.Published versio

Corrigendum: the unknown and the unexplored: insights into the Pacific deep-sea following NOAA CAPSTONE expeditions

Published versio

The unknown and the unexplored: insights Into the Pacific deep-sea following NOAA CAPSTONE expeditions

Over a 3-year period, the National Oceanic and Atmospheric Administration (NOAA) organized and implemented a Pacific-wide field campaign entitled CAPSTONE: Campaign to Address Pacific monument Science, Technology, and Ocean NEeds. Under the auspices of CAPSTONE, NOAA mapped 597,230 km2 of the Pacific seafloor (with ∼61% of mapped area located within US waters), including 323 seamounts, conducted 187 ROV dives totaling 891.5 h of ROV benthic imaging time, and documented >347,000 individual organisms. This comprehensive effort yielded dramatic insight into differences in biodiversity across depths, regions, and features, at multiple taxonomic scales. For all deep sea taxonomic groups large enough to be visualized with the ROV, we found that fewer than 20% of the species were able to be identified. The most abundant and highest diversity taxa across the dataset were from three phyla (Cnidaria, Porifera, and Echinodermata). We further examined these phyla for taxonomic assemblage patterns by depth, geographic region, and geologic feature. Within each taxa, there were multiple genera with specific distribution and abundance by depth, region, and feature. Additionally, we observed multiple genera with broad abundance and distribution, which may focus future ecological research efforts. Novel taxa, records, and behaviors were observed, suggestive of many new types of species interactions, drivers of community composition, and overall diversity patterns. To date, only 13.8% of the Pacific has been mapped using modern methods. Despite the incredible amount of new known and unknown information about the Pacific deep-sea, CAPSTONE is far from the culminating experience the name suggests. Rather, it marks the beginning of a new era for exploration that will offer extensive opportunities via mapping, technology, analysis, and insights.Published versio

Exploration of the Canyon-Incised Continental Margin of the Northeastern United States Reveals Dynamic Habitats and Diverse Communities

<div><p>The continental margin off the northeastern United States (NEUS) contains numerous, topographically complex features that increase habitat heterogeneity across the region. However, the majority of these rugged features have never been surveyed, particularly using direct observations. During summer 2013, 31 Remotely-Operated Vehicle (ROV) dives were conducted from 494 to 3271 m depth across a variety of seafloor features to document communities and to infer geological processes that produced such features. The ROV surveyed six broad-scale habitat features, consisting of shelf-breaching canyons, slope-sourced canyons, inter-canyon areas, open-slope/landslide-scar areas, hydrocarbon seeps, and Mytilus Seamount. Four previously unknown chemosynthetic communities dominated by <i>Bathymodiolus</i> mussels were documented. Seafloor methane hydrate was observed at two seep sites. Multivariate analyses indicated that depth and broad-scale habitat significantly influenced megafaunal coral (58 taxa), demersal fish (69 taxa), and decapod crustacean (34 taxa) assemblages. Species richness of fishes and crustaceans significantly declined with depth, while there was no relationship between coral richness and depth. Turnover in assemblage structure occurred on the middle to lower slope at the approximate boundaries of water masses found previously in the region. Coral species richness was also an important variable explaining variation in fish and crustacean assemblages. Coral diversity may serve as an indicator of habitat suitability and variation in available niche diversity for these taxonomic groups. Our surveys added 24 putative coral species and three fishes to the known regional fauna, including the black coral <i>Telopathes magna</i>, the octocoral <i>Metallogorgia melanotrichos</i> and the fishes <i>Gaidropsarus argentatus</i>, <i>Guttigadus latifrons</i>, and <i>Lepidion guentheri</i>. Marine litter was observed on 81% of the dives, with at least 12 coral colonies entangled in debris. While initial exploration revealed the NEUS region to be both geologically dynamic and biologically diverse, further research into the abiotic conditions and the biotic interactions that influence species abundance and distribution is needed.</p></div

Species richness by depth.

<p>(A) corals. (B) fishes. (C) crustaceans. Best-fit linear trend lines are included.</p

Non-metric multi-dimensional scaling plots based on Sorensen's Index of Similarity.

<p>(A) corals. (B) fishes. (C) crustaceans. Significantly (SIMPROF, p<0.05) dissimilar assemblage clusters are noted. Dive numbers are noted. Circle size denotes median depth of dive. Pink = Open Slope/Landslide Scar, Orange = Inter-canyon Slope, Gray = Cold Seep, Blue = Slope Canyon, Dark Blue = Shelf-breaching Canyon, Red = Seamount.</p

Total number of morphospecies observed across six broad-scale habitat features for three taxonomic groups.

<p>^a Straight-line distance travelled over ground was approximated using the measuring tool in ArcMap.</p><p>Depth range and total distance travelled per area are included. Dive numbers are included.</p

Abundance estimates of dominant species in the region.

<p>(A) <i>Paragorgia</i> spp. (B) <i>Primnoa</i>? <i>resedaeformis</i>. (C) <i>Synaphobranchus</i> spp. (D) <i>Neocyttus helgae</i>. (E) <i>Chaceon quinquedens</i>. Circle size corresponds to number observed 10 m^-2 as shown in key inset at lower left of each graph. Black symbols denote dives in which no species were observed. OS/L = Open Slope/Landslide Scar, IS = Inter-canyon Slope, CS = Cold Seep, SC = Slope Canyon, SBC = Shelf-breaching Canyon, SMT = Seamount.</p

DistLM results.

<p>Marginal test results followed by results from the BEST model using the AIC criterion. P-values in bold are significant (Bonferroni Adjustment, α = 0.01).</p

Cumulative number of putative species (solid line) by taxon observed across all dives conducted.

<p>95% confidence intervals are indicated (dotted lines).</p