Structure and Trophic Niches in Mobile Epifauna Assemblages Associated With Seaweeds and Habitats of Syngnathid Fishes in Cíes Archipelago (Atlantic Islands Marine National Park, North West Iberia)

Syngnathids are vulnerable fishes closely associated with seaweeds and seagrass, which provide shelter and food resources. Even though most syngnathids commonly feed on small crustaceans, the feeding regimes may differ depending on the species and prey availability. This is the first monitoring study to explain syngnathid abundances and dietary regimes within macroalgal beds in Cíes Archipelago (Atlantic Islands Marine National Park, North West Iberian Peninsula). We sampled the epifaunal assemblages in seaweed communities dominated by the canopy-forming macroalgae Gongolaria baccata and Codium spp. seasonally during 2 years. The epifaunal structure was mostly represented by harpacticoid copepods, amphipods (especially gammarids) and gastropods. Epifauna exhibited low plant-host specificity and a higher dominance of amphipods on the more structurally complex macroalgae G. baccata. The epifaunal assemblages and syngnathid specimens were assessed for trophic structure using stable isotopes (δ13C and δ15N). The three syngnathids (Hippocampus guttulatus, Syngnathus acus, and Entelurus aequoreus) inhabiting Cíes Archipelago were sympatric. They occupied highly similar trophic positions (TPs), but differed in niche size, in such a way that the snake pipefish E. aequoreus would likely feed on smaller prey. The assessment of the feeding regime in the dominant great pipefish S. acus revealed that amphipods mostly contributed to bulk diet, followed by isopods, carideans, and copepods, whereas mysidaceans were not highly consumed. Seasonal changes in both epifaunal structure and syngnathids abundance confirmed that syngnathids are seasonal residents in Cíes Archipelago, migrating to other areas in autumn when the seaweed cover is drastically reduced and the epifaunal structure modified. This study showed the importance of Gongolaria assemblages in Cíes Archipelago, providing rich dietary sources and potentially contributing to higher abundances and diversity of syngnathids. Ongoing cover reduction in Gongolaria assemblages in certain regions (e.g., Mediterranean) should be considered a potential ecological concern for syngnathids and accompanying fauna, requiring further investigations.

Ecological Studies on Marine Algal-Dwelling Copepoda (Harpacticoida) from Wellington, New Zealand

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>

Ecological Studies on Marine Algal-Dwelling Copepoda (Harpacticoida) from Wellington, New Zealand

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>

On some deep-sea Stenheliinae from the Gulf of California and the west coast of the Baja California Peninsula (Mexico): Wellstenhelia euterpoides sp. nov., and Wellstenvalia wellsi gen. et sp. nov. (Copepoda: Harpacticoida: Miraciidae)

At present, only 11 species of harpacticoid copepods have been described from the deep sea of the Gulf of California and the west coast of the Baja California Peninsula. These efforts had until recently been focused exclusively on the families Ameiridae Boeck, Argestidae Por, and Rhizothrichidae Por. Preliminary analyses revealed also an important contribution of the subfamily Stenheliinae Brady (Miraciidae Dana) to the overall species richness and diversity of deep-sea benthic copepods from the west coast of the Baja California Peninsula, and the central and southern Gulf of California. One new species of the genus Wellstenhelia Karanovic & Kim, 2014, We. euterpoides sp. nov., and one new genus and species, Wellstenvalia wellsi gen. et sp. nov., are herein described from sediment samples taken at eight sampling stations in the west coast of the Baja California Peninsula and in the central and southern Gulf of California. Wellstenhelia euterpoides sp. nov. seems to be closely related to We. euterpe Karanovic & Kim, 2014 with which it shares the reduced armature complement of the baseoendopod of the female fifth leg. The so far monotypic genus Wellstenvalia gen. nov. was found to be closely related to Muohuysia Özdikmen, 2009 and Wellstenhelia. Some comments on the relationships between the new genus proposed here and other stenheliin genera and species are provided as a contribution towards the monophyly of the subfamily.

Deep sea without limits—four new closely related species of Emertonia Wilson, 1932 (Copepoda: Harpacticoida: Paramesochridae) show characters with a world-wide distribution

The large-scale dispersal of deep-sea harpacticoid copepods is an increasing focus for ecological studies. A fundamental prerequisite for monitoring and explaining their geographical distribution is precise descriptions of their morphology. Four new, closely related species of the family Paramesochridae (Copepoda, Harpacticoida) were found in the deep sea of the Pacific (San Diego Trough and off Chile), the Atlantic Ocean (Porcupine Abyssal Plain and Angola Basin), and the Atlantic and Indian Ocean sectors of the Southern Ocean (Weddell Sea and off Crozet Island). The discovery of Emertonia berndi sp. nov., E. hessleri sp. nov., E. ilse sp. nov., and E. serrata sp. nov. increases the number of known deep-sea species in this genus to ten. The new species are placed in Emertonia Wilson, 1932 because of their one-segmented endopods on the second and third swimming legs. The presence of a two-segmented endopod on the fourth swimming leg allocates them to the “andeep-group” within this genus. The four species can be distinguished from their congeners by the strongly serrated spines on the exopods of their swimming legs and an outwardly directed flexible seta on the exopod of the fifth leg. It is conveivable that these two specific characters evolved only once in the genus Emertonia. Their apparently cosmopolitan distribution covers thousands of kilometres and spans all major oceans. This biogeographical pattern may be explained by resuspension events followed by passive transport by benthic currents. Discrepancies in their dispersal ranges may be a result of changing geological and oceanographic boundaries.

Epibiont Assemblages on Nesting Hawksbill Turtles Show Site-Specificity in the Persian Gulf

Sea turtle epibionts can provide insights into the hosts' habitat use. However, at present, there is a lack of information on sea turtle epibiont communities in many locations worldwide. Here, we describe the epibiont communities of 46 hawksbill turtles (Eretmochelys imbricata) in the Persian Gulf. Specifically, we sampled 28 turtles from the Dayyer-Nakhiloo National Park (DNNP) in the northern Gulf and 18 turtles from Shibderaz beach in the Strait of Hormuz. A total of 54 macro, meio, and micro-epibiont taxa were identified, including 46 taxa from Shibderaz and 29 taxa from DNNP. The barnacles Chelonibia testudinaria and Platylepas hexastylos, as well as harpacticoid copepods and Rotaliid foraminifers, had the highest frequency of occurrence found on almost all turtle individuals. Harpacticoids were the most abundant epizoic taxa (19.55 ± 3.9 ind. per 9 cm2) followed by forams (Quinqueloculina spp.: 6.25 ± 1.5 ind. per 9 cm2 and Rotaliids: 6.02 ± 1.3 ind. per 9 cm2). Our results showed significant differences between the study sites in the composition of micro and macro-epibiont communities found on hawksbill turtles. We speculate that the differences in epibiont communities were largely influenced by local environmental conditions.

Fatty acid bioconversion in harpacticoid copepods in a changing environment: a transcriptomic approach

By 2100, global warming is predicted to significantly reduce the capacity of marine primary producers for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis. Primary consumers such as harpacticoid copepods (Crustacea) might mitigate the resulting adverse effects on the food web by increased LC-PUFA bioconversion. Here, we present a high-quality de novo transcriptome assembly of the copepod Platychelipus littoralis , exposed to changes in both temperature (+3°C) and dietary LC-PUFA availability. Using this transcriptome, we detected multiple transcripts putatively coding for LC-PUFA-bioconverting front-end fatty acid (FA) desaturases and elongases, and performed phylogenetic analyses to identify their relationship with sequences of other (crustacean) taxa. While temperature affected the absolute FA concentrations in copepods, LC-PUFA levels remained unaltered even when copepods were fed an LC-PUFA-deficient diet. While this suggests plasticity of LC-PUFA bioconversion within P. littoralis , none of the putative front-end desaturase or elongase transcripts was differentially expressed under the applied treatments. Nevertheless, the transcriptome presented here provides a sound basis for future ecophysiological research on harpacticoid copepods. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids'.