Recent years have seen increased survey and sampling expeditions to the Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyss, driven by commercial interests from contractors in the potential extraction of polymetallic nodules in the region. Part of the International Seabed Authority (ISA) regulatory requirements are that these contractors undertake environmental research expeditions to their CCZ exploration claims following guidelines approved by the ISA Legal and Technical Commission (ISA, 2010). Section 9 (e) of these guidelines instructs contractors to " . . . collect data on the sea floor communities specifically relating to megafauna, macrofauna, meiofauna, microfauna, nodule fauna and demersal scavengers". There are a number of methodological challenges to this, including the water depth (4000-5000 m), extremely warm surface waters (~28˝C) compared to bottom water (~1.5˝C) and great distances to ports requiring a large and long seagoing expedition with only a limited number of scientists. Both scientists and regulators have recently realized that a major gap in our knowledge of the region is the fundamental taxonomy of the animals that live there; this is essential to inform our knowledge of the biogeography, natural history and ultimately our stewardship of the region. Recognising this, the ISA is currently sponsoring a series of taxonomic workshops on the CCZ fauna and to assist in this process we present here a series of methodological pipelines for DNA taxonomy (incorporating both molecular and morphological data) of the macrofauna and megafauna from the CCZ benthic habitat in the recent ABYSSLINE cruise program to the UK-1 exploration claim. A major problem on recent CCZ cruises has been the collection of high-quality samples suitable for both morphology and DNA taxonomy, coupled with a workflow that ensures these data are made available. The DNA sequencing techniques themselves are relatively standard, once good samples have been obtained. The key to quality taxonomic work on macrofaunal animals from the tropical abyss is careful extraction of the animals (in cold, filtered seawater), microscopic observation and preservation of live specimens, from a variety of sampling devices by experienced zoologists at sea. Essential to the long-term iterative building of taxonomic knowledge from the CCZ is an "end-to-end" methodology to the taxonomic science that takes into account careful sampling design, at-sea taxonomic identification and fixation, post-cruise laboratory work with both DNA and morphology and finally a careful sample and data management pipeline that results in specimens and data in accessible open museum collections and online repositories.A key goal of our sampling protocol for the CCZ is the study of both the DNA sequences and morphology of the animals. Both the genetic sequences of animals, and their external shape and morphology hold huge amounts of useful data for understanding their biology. Over the last 250 years since Linnaeus, humans have been busy building a remarkable and vas...

The marine environment is characterized by few physical barriers, and pelagic fishes commonly show high migratory potential and low, albeit in some cases statistically significant, levels of genetic divergence in neutral genetic marker analyses. However, it is not clear whether low levels of differentiation reflect spatially separated populations experiencing gene flow or shallow population histories coupled with limited random genetic drift in large, demographically isolated populations undergoing independent evolutionary processes. Using information for nine microsatellite loci in a total of 1951 fish, we analyzed genetic differentiation among Atlantic herring from eleven spawning locations distributed along a longitudinal gradient from the North Sea to the Western Baltic. Overall genetic differentiation was low (theta = 0.008) but statistically significant. The area is characterized by a dramatic shift in hydrography from the highly saline and temperature stable North Sea to the brackish Baltic Sea, where temperatures show high annual variation. We used two different methods, a novel computational geometric approach and partial Mantel correlation analysis coupled with detailed environmental information from spawning locations to show that patterns of reproductive isolation covaried with salinity differences among spawning locations, independent of their geographical distance. We show that reproductive isolation can be maintained in marine fish populations exhibiting substantial mixing during larval and adult life stages. Analyses incorporating genetic, spatial, and environmental parameters indicated that isolating mechanisms are associated with the specific salinity conditions on spawning locations.

Three new Ophryotrocha species are described from sites with high levels of organic carbon flux including a whale-fall at 125 m depth off the Swedish coast and sediment sampled at 104 m depth beneath a fish farm in a Norwegian fjord. Phylogenetic analyses based on the nuclear gene H3 and the mitochondrial genes COI and 16S using MrBayes and Maximum Likelihood analyses show that Ophryotrocha eutrophila sp. nov. is a close relative to Ophryotrocha puerilis, while Ophryotrocha craigsmithi sp. nov. falls together with Palpiphitime lobifera, and Ophryotrocha scutellus sp. nov. occur within the 'hartmanni' clade. The genus Ophryotrocha is in our study monophyletic only if the genera Iphitime and Palpiphitime are included. Two representatives of Ophryotrocha previously described from anthropogenically-enriched sediments are here reported for the first time in very high abundance from a naturally occurring habitat. We suggest that whale falls are important habitats for the evolution of ecosystem services such as the degradation of complex organic compounds.

The removal of thousands of structures associated with oil and gas development from the world's oceans is well underway, yet the environmental impacts of this decommissioning practice remain unknown. Similar impacts will be associated with the eventual removal of offshore wind turbines. We conducted a global survey of environmental experts to guide best decommissioning practices in the North Sea, a region with a substantial removal burden. In contrast to current regulations, 94.7% of experts (36 out of 38) agreed that a more flexible case‐by‐case approach to decommissioning could benefit the North Sea environment. Partial removal options were considered to deliver better environmental outcomes than complete removal for platforms, but both approaches were equally supported for wind turbines. Key considerations identified for decommissioning were biodiversity enhancement, provision of reef habitat, and protection from bottom trawling, all of which are negatively affected by complete removal. We provide recommendations to guide the revision of offshore decommissioning policy, including a temporary suspension of obligatory removal.