An Assessment of Mobile Predator Populations along Shallow and Mesophotic Depth Gradients in the Hawaiian Archipelago.

Large-bodied coral reef roving predators (sharks, jacks, snappers) are largely considered to be depleted around human population centers. In the Hawaiian Archipelago, supporting evidence is primarily derived from underwater visual censuses in shallow waters (=30?m). However, while many roving predators are present or potentially more abundant in deeper strata (30-100?m+), distributional information remains sparse. To partially fill that knowledge gap, we conducted surveys in the remote Northwestern Hawaiian Islands (NWHI) and populated Main Hawaiian Islands (MHI) from 2012-2014 using baited remote underwater stereo-video. Surveys between 0-100?m found considerable roving predator community dissimilarities between regions, marked conspicuous changes in species abundances with increasing depth, and largely corroborated patterns documented during shallow water underwater visual censuses, with up to an order of magnitude more jacks and five times more sharks sampled in the NWHI compared to the MHI. Additionally, several species were significantly more abundant and larger in mesophotic versus shallow depths, which remains particularly suggestive of deep-water refugia effects in the MHI. Stereo-video extends the depth range of current roving predator surveys in a more robust manner than was previously available, and appears to be well-suited for large-scale roving predator work in the Hawaiian Archipelago

Mesophotic reef fish assemblages of the remote St. Peter and St. Paul’s Archipelago, Mid-Atlantic Ridge, Brazil

Mesophotic reef fish assemblages (30-90 m depth) of the small and remote St. Peter and St. Paul's Archipelago (SPSPA), Mid-Atlantic Ridge, Brazil, were characterized using remotely operated vehicles. Ordination analyses identified distinct fish assemblages in the upper (30-50 m) and lower (50-90 m) mesophotic zones, the former characterized by high abundances of species that are also abundant at euphotic reefs (Caranx lugubris, Melichthys niger, Stegastes sanctipauli and Chromis multilineata) and the latter dominated by two mesophotic specialists (Prognathodes obliquus and Chromis enchrysura). Planktivores dominated fish assemblages, particularly in the upper mesophotic zone, possibly due to a greater availability of zooplankton coming from the colder Equatorial Undercurrent in mesophotic depths of the SPSPA. Turf algae, fleshy macroalgae and scleractinian corals dominated benthic assemblages between 30 and 40 m depth, while bryozoans, black corals and sponges dominated between 40 and 90 m depth. Canonical correspondence analysis explained 74 % of the relationship between environmental characteristics (depth, benthic cover and complexity) and structure of fish assemblages, with depth as the most important independent variable. Juveniles of Bodianus insularis and adults of P. obliquus and C. enchrysura were clearly associated with branching black corals (Tanacetipathes spp.), suggesting that black corals play key ecological roles in lower mesophotic reefs of the SPSPA. Results from this study add to the global database about mesophotic reef ecosystems (MREs) and provide a baseline for future evaluations of possible anthropogenic and natural disturbances on MREs of the SPSPA.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPqCNPqFundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Univ Sao Paulo, Inst Oceanog, Programa Posgrad Oceanog Biol, BR-05508120 Sao Paulo, SP, BrazilUniv Fed Paraiba, Programa Posgrad Ciencias Biol Zool, BR-58059900 Joao Pessoa, PB, BrazilUniv Fed Paraiba, Programa Posgrad Ecol & Monitoramento Ambiental, BR-58297000 Rio Tinto, PB, BrazilUniv Estadual Paraiba, Programa Posgrad Ecol & Conservac, BR-58109753 Campina Grande, PB, BrazilUniv Fed Pernambuco, Dept Oceanog, Ctr Tecnol & Geociencias, BR-50670901 Recife, PE, BrazilUniv Fed Paraiba, Ctr Ciencias Exatas & Nat, Dept Sistemat & Ecol, BR-58051900 Joao Pessoa, PB, BrazilInst Pesquisas Jardim Bot Rio De Janeiro, Rio De Janeiro, RJ, BrazilUniv Fed Sao Paulo, Inst Mar, Campus Baixada Santista, BR-11030400 Santos, SP, BrazilUniv Fed Rio de Janeiro, Inst Biol, BR-21944970 Rio De Janeiro, RJ, BrazilUniv Fed Rio de Janeiro, SAGE COPPE, BR-21944970 Rio De Janeiro, RJ, BrazilUniv Sao Paulo, Inst Oceanog, Dept Oceanog Biol, BR-05508120 Sao Paulo, SP, BrazilUniv Fed Paraiba, Dept Engn & Meio Ambiente, BR-58297000 Rio Tinto, PB, BrazilUniv Fed Sao Paulo, Inst Mar, Campus Baixada Santista, BR-11030400 Santos, SP, BrazilCNPq: 557185/09-2CNPq: 484875/2011-6Web of Scienc