ALBERT

Description:    In this paper, we argue that understanding marine ecosystem functioning requires a thorough appreciation of the role of intraguild predation to system dynamics. The theoretical predictions of intraguild predation models might explain some of the community features observed in marine ecosystems such as low diversity in upwelling and productive systems and species alternation in response to moderate external forcing. Finally, we argue that an ecosystem approach to fisheries requires that the size–structure of fish populations should be taken into account and that it is extremely important to account for the predators of early stages (eggs and larvae) to gain a thorough understanding of the key interactions between species. Content Type Journal Article Pages 1-8 DOI 10.1007/s00227-011-1699-2 Authors Xabier Irigoien, AZTI—Tecnalia, Herrera kaia, 20110 Pasaia, Spain André de Roos, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both species were positively correlated with ambient surface chlorophyll a (chl a ). No evidence was found for salp clogging even at dense surface concentrations of up to 7 μg chl a L −1 . However, gut pigment concentrations had a lower range than ambient pigment concentrations, suggesting that salps increased retention times of ingested material in low-food environments. For medium-sized I. racovitzai and S. thompsoni , estimated individual daily rations reached 7–10 and 〉100% of body carbon in winter and summer, respectively. Daily respiratory needs of I. racovitzai and S. thompsoni accounted for 28 and 22% of daily carbon assimilation based on pigment ingestion rates in winter, and for 2 and 1% in summer, respectively. The grazing impact of the salp populations on the phytoplankton standing stock was negligible during all seasons due to generally low salp densities. Fatty acid trophic biomarkers in the salps suggest high year-round contributions of flagellates and modest contributions of diatoms to the salp’s diet. These markers showed low seasonal variability for I. racovitzai . The more pronounced seasonality of trophic markers in S. thompsoni were likely related to their generally deeper residence depth in winter linked to a seasonal alternation of sexual and asexual generations. Content Type Journal Article Pages 1-18 DOI 10.1007/s00227-011-1709-4 Authors Lena von Harbou, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27515 Bremerhaven, Germany Corinna D. Dubischar, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27515 Bremerhaven, Germany Evgeny A. Pakhomov, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, Canada Brian P. V. Hunt, Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4, Canada Wilhelm Hagen, Marine Zoology, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany Ulrich V. Bathmann, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27515 Bremerhaven, Germany Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    Variation in female sperm storage is explained, in part, by the amount of sperm transferred at mating. Laboratory mating experiments were conducted on Eurypanopeus depressus and Rhithropanopeus harrisii from the Chesapeake Bay and Pachygrapsus transversus from Florida, while mated pairs of Uca beebei and U. terpsichores were collected from mudflats in Panama. All experiments and collections were conducted during the summer of 2006 and 2007. More sperm was transferred to larger than smaller females, and by species with long copulation durations ( R. harrisii and E. depressus ). These two species live in cryptic habitats, have high sperm/egg ratios, and likely store sperm across multiple broods. In contrast, P. transversus and U. beebei mate conspicuously, have short copulations, transfer fewer sperm, and have low sperm/egg ratios. Comparisons of sperm transfer across different mating strategies and habitats provide a better understanding of female sperm storage in the Brachyura. Content Type Journal Article Pages 1-10 DOI 10.1007/s00227-011-1687-6 Authors Paula J. Rodgers, Biology Department, University of Maryland, College Park, MD 20742, USA Marjorie L. Reaka, Biology Department, University of Maryland, College Park, MD 20742, USA Anson H. Hines, Smithsonian Environmental Research Center, Edgewater, MD 21037, USA Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    The existence of three distinct populations is widely accepted for the finless porpoise ( Neophocaena phocaenoides ) in Chinese waters: the Yellow Sea, Yangtze River, and South China Sea populations. Here, we use nine species-specific microsatellite loci, the complete mitochondrial DNA control region (912 bp), and the complete mitochondrial cytochrome b gene (1,140 bp) to further investigate potential population stratification in the Yellow Sea using 147 finless porpoise samples from the Bohai Sea and adjacent northern Yellow Sea, two regions that were largely underrepresented in previous genetic studies. Our F -statistics analyses confirm the previously described three populations, but further demonstrate significant genetic differentiation between the [Bohai + northern Yellow] Sea and the southern Yellow Sea. On the other hand, median-joining network analyses do not exhibit well-differentiated haplotype groups among different geographic populations, suggesting the existence of shared ancestral haplotypes. Levels of microsatellite diversity are moderate to high (mean H E  = 0.794) among the 147 [Bohai + northern Yellow] Sea finless porpoises and no recent bottleneck was detected, whereas mtDNA control region and cytochrome b gene diversity is low to moderate. The microsatellite genotypic and mtDNA haplotypic data also confirm the presence of mother-calf pairs in single-net bycatch cases. The results presented here highlight the necessity to treat the [Bohai + northern Yellow] Sea population (highly impacted by anthropogenic threats) as a separate Management Unit. Content Type Journal Article Pages 1-14 DOI 10.1007/s00227-011-1692-9 Authors Xiang Li, URBE-Laboratory of Evolutionary Genetics and Ecology (LEGE), Department of Biology, University of Namur (FUNDP), Rue de Bruxelles 61, 5000 Namur, Belgium Yingying Liu, Ocean College, Shandong University at Weihai, 264209 Weihai, People’s Republic of China Athanasia C. Tzika, Department of Genetics and Evolution, Laboratory of Artificial and Natural Evolution (LANE), Sciences III, 30, Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland Qian Zhu, Ocean College, Shandong University at Weihai, 264209 Weihai, People’s Republic of China Karine Van Doninck, URBE-Laboratory of Evolutionary Genetics and Ecology (LEGE), Department of Biology, University of Namur (FUNDP), Rue de Bruxelles 61, 5000 Namur, Belgium Michel C. Milinkovitch, Department of Genetics and Evolution, Laboratory of Artificial and Natural Evolution (LANE), Sciences III, 30, Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    Amphipods along the western Antarctic Peninsula appear to gain refuge from predators by associating with chemically defended macroalgae rather than palatable macroalgae. However, nothing is known about amphipod activity at night. If foraging on non-chemically defended macroalgae regularly occurs, then nocturnal foraging seems beneficial since visual predators are disadvantaged. To test this hypothesis, we collected three common macroalgal species and affiliated mesograzers, approximately 3 h before and after sunset. All associated mesofauna were counted and densities recorded. Amphipod densities were significantly decreased during the night on the chemically defended Desmarestia menziesii , while significantly increased on the palatable Iridaea cordata . Additionally, the amphipod Gondogeneia antarctica was found in significantly higher densities at night on Palmaria decipiens , a species shown to be readily eaten by G. antarctica and omnivorous fish. We believe that chemically defended macroalgae act as a refuge for mesograzers during the day, while more widespread foraging occurs at night. Content Type Journal Article Pages 1-7 DOI 10.1007/s00227-011-1700-0 Authors Craig F. Aumack, Department of Marine Science, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA Charles D. Amsler, Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA James B. McClintock, Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA Bill J. Baker, Department of Chemistry, University of South Florida, Tampa, FL 33620, USA Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    In diet analyses of seabirds, fatty acid signatures (FAS) can be used to overcome biases due to differential digestion of prey and enable the analysis of very digested diet samples. We applied FAS analysis to stomach contents of a small sub-Antarctic seabird, the Thin-billed Prion Pachyptila belcheri , which feeds mainly on squid during incubation and on crustacea during chick rearing. This seasonal dietary switch of Thin-billed prions was reflected in differences in FAS in regurgitates, as were inter-annual differences in diet composition. A discriminant function analysis correctly classified 93.4% of cases with respect to year (2006–2008) and stage of the breeding cycle (incubation versus chick rearing). The dominant types of crustacea in the diet of Thin-billed prions (amphipods Themisto gaudichaudii , euphausiids, decapods Munida gregaria , and calanoid copepods) were distinguished well by characteristic FAS patterns. However, the FAS of the two main types of prey by volume, amphipods T. gaudichaudii and squid Gonatus antarcticus , were similar to each other. Although FAS were successfully applied in the analysis of prey in stomach contents of prions, FAS of some prey species were similar and may not be distinguishable from each other if used in quantitative diet analyses. Content Type Journal Article Pages 1-9 DOI 10.1007/s00227-011-1693-8 Authors Petra Quillfeldt, Max-Planck-Institut für Ornithologie, Vogelwarte Radolfzell, Radolfzell, Germany Juan F. Masello, Max-Planck-Institut für Ornithologie, Vogelwarte Radolfzell, Radolfzell, Germany Paul Brickle, Fisheries Department, Falkland Islands Government, Directorate of Natural Resources, P.O. Box 598, Stanley, Falkland Islands Dominik Martin-Creuzburg, Limnologisches Institut, Universität Konstanz, Konstanz, Baden-Württemberg, Germany Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    The quahog Mercenaria mercenaria has been introduced repeatedly to the Pacific coast of North America, but only one population is known to have become established. In the 1970s, the population of M. mercenaria at Colorado Lagoon, in Los Angeles County, California (33 o 46′16″N, 118 o 08′05″W), was estimated at more than 300,000 individuals. To determine the current status of this non-indigenous species (NIS), in 2009, we sampled 57 intertidal and 20 shallow subtidal plots, identifying and quantifying collected bivalves. No quahogs were found among the 2,490 living bivalves in our plots, though two were found intertidally outside of our plots. The M. mercenaria population has thus collapsed since 1980, but the native community has not recovered. Six of the fourteen living bivalve species we encountered were NIS; three are new records for the location, including the clam Venerupis philippinarum , which made up 87.6% of collected individuals. Though M. mercenaria is likely on its way to extinction on the US Pacific coast, the bivalve assemblage at this location remains heavily dominated by NIS. Content Type Journal Article Pages 1-13 DOI 10.1007/s00227-011-1703-x Authors Jennifer L. Burnaford, Department of Biological Science, California State University Fullerton, P.O. Box 6850, Fullerton, CA 92834-6850, USA Scottie Y. Henderson, Department of Biological Science, California State University Fullerton, P.O. Box 6850, Fullerton, CA 92834-6850, USA Bruno Pernet, Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840, USA Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    The commercially and ecologically valuable sandeel (Ammodytes ssp.) make distinct vertical shifts between an inactive stage, during which they seek refuge in the sand, and a pelagic schooling stage, during which they forage. This characteristic discontinuous foraging pattern constitutes a challenge to fishery biologists and has consequences for a wide range of predators ranging from birds and mammals to commercially important species. However, experimental studies that shed light on the primary drivers of foraging activity in fish are rare. In the present study, whole schools of sandeel ( A . tobianus ) were caught in August in east Denmark (65°02′30N; 12°37′00E) and kept in large tanks in the laboratory. It was found that the amount of food ingested and memory of past days feeding history are primary drivers of foraging activity at the level of the entire school, whereas external factors such as prey concentration and temperature are merely secondary drivers. Content Type Journal Article Pages 1-9 DOI 10.1007/s00227-011-1691-x Authors Mikael van Deurs, National Institute of Aquatic Resources, Technical University of Denmark, Jaegersborg Alle 1, Charlottenlund Castle, 2920 Charlottenlund, Denmark Jane W. Behrens, National Institute of Aquatic Resources, Technical University of Denmark, Jaegersborg Alle 1, Charlottenlund Castle, 2920 Charlottenlund, Denmark Thomas Warnar, National Institute of Aquatic Resources, Technical University of Denmark, Jaegersborg Alle 1, Charlottenlund Castle, 2920 Charlottenlund, Denmark John Fleng Steffensen, Marine Biological Laboratory, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    As settled juveniles and adults, blue rockfish ( Sebastes mystinus ) are nonmigratory inhabitants of kelp and rocky reef habitats along the California coast, USA, and prior to settlement, they possess a pelagic larval and juvenile stage lasting 3–5 months. A previous study of adults revealed two cryptic species within S. mystinus and evidence of reproductive isolation in a region where both cryptic adults co-occur. Given this pattern of reproductive isolation, we investigated the degree of hybridization or introgression in individual year-classes shortly after juvenile settlement in two different years (2001 and 2002). Using microsatellite markers, we found little indication of hybridization in new juvenile year-classes despite an adult population that comprised both cryptic species. However, we found an average of two percent of hybrid or introgressed individuals in regions with a low frequency of one of the two species. Therefore, while the lack of hybrids or introgression supports the hypothesis of reproductive isolation between the cryptic species within S. mystinus , the age-structured analysis also revealed a spatial pattern of low-frequency differences in the number of introgressed individuals. These results suggest that reproductive barriers may breakdown when one of the two species predominates the regional adult gene pool. Content Type Journal Article Pages 1-13 DOI 10.1007/s00227-011-1694-7 Authors Martha O. Burford, Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA Giacomo Bernardi, Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA Mark H. Carr, Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162

Description:    The diet of cavity sponges on the narrow fringing reefs of Curaçao, Caribbean was studied. The origin and resources of the bulk food of these sponges, i.e., dissolved organic matter (DOM), were identified using stable carbon and nitrogen isotopes and fatty acid biomarkers. We found that phytoplankton and its derived DOM from the adjacent open sea and from reef overlying water is not the main source of food for most of the sponges examined nor is bacterioplankton. Interestingly, dual stable isotope signatures (δ 13 C org , δ 15 N org ) and fatty acid biomarkers appoint coral mucus and organic matter derived from crustose coralline algae (CCA) as probable food sources for encrusting sponges. Mucus-derived DOM may contribute up to 66% to the diet of examined sponges based on results of dual isotope mixing model analysis. The contribution of CCA (as purported representative for benthic algae) was smaller with values up to 31%. Together, mucus- and CCA-derived substrates contributed for 48–73% to the diet of sponges. The presence of the exogenous fatty acid 20:4ω6 in sponges, which is abundant in coral mucus of Madracis mirabilis and in CCA, highlights these reef-derived resources as sources of nutrition for DOM feeding cavity sponges. The relatively high concentrations of exogenous 20:4ω6 in all sponges examined supports our hypothesis that the bulk of the food of the cavity sponge community is reef-derived. Our results imply that cavity sponges play an important role in conserving food and energy produced within the reef. Content Type Journal Article Pages 1-14 DOI 10.1007/s00227-011-1681-z Authors Fleur C. van Duyl, Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands Leon Moodley, Netherlands Institute of Ecology (NIOO), Korringaweg 7, 4401 NT Yerseke, The Netherlands Gerard Nieuwland, Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands Lennart van Ijzerloo, Netherlands Institute of Ecology (NIOO), Korringaweg 7, 4401 NT Yerseke, The Netherlands Rob W. M. van Soest, Zoological Museum, University of Amsterdam, P.O. Box 94766, 1090 GT Amsterdam, The Netherlands Marco Houtekamer, Netherlands Institute of Ecology (NIOO), Korringaweg 7, 4401 NT Yerseke, The Netherlands Erik H. Meesters, Wageningen IMARES, P.O. Box 167, Location Texel, Landsdiep 4, 1797SZ ‘t Horntje, 1790 AD Den Burg, The Netherlands Jack J. Middelburg, Netherlands Institute of Ecology (NIOO), Korringaweg 7, 4401 NT Yerseke, The Netherlands Journal Marine Biology Online ISSN 1432-1793 Print ISSN 0025-3162