Phenotypic differences may limit the potential for habitat restoration involving species translocation: a case study of shape ecophenotypes in different populations of Modiolus modiolus (Mollusca: Bivalvia)

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Genetic monitoring of deep‐water exploited banks of the precious Sardinia coral Corallium rubrum (L., 1758): useful data for a sustainable management

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Correlates of lake use by breeding common scoters in Scotland

1. Many populations of sea‐ducks, which typically winter at sea but breed on fresh water, are declining. Numbers of common scoters Melanitta nigra (L.) breeding in Scotland halved between 1995 and 2007, despite most breeding sites having special conservation status. To identify potential conservation measures, a 3‐year study was conducted, investigating correlates of lake use by scoters. 2. At 26 scoter breeding lakes, food abundance (macroinvertebrates) and foraging habitats (substrates, water depth) were measured, and their associations with scoter lake use explored using multi‐model inference. Correlates of macroinvertebrate abundance (water quality, fish abundance) were also investigated. 3. Averaged over 3 years (2009–2011), these lakes held 26.7 (SE 6.3) females, around half the Scottish breeding population. Scoters occurred more often at lakes having abundant large‐bodied invertebrates and extensive shallow water. Lakes where the average weight of the largest invertebrate in each sample exceeded 4 mg had 9.2 times (females) or 27 times (broods) more scoter records than other lakes. Lakes where water depths (10 m from the shore) averaged less than 1.3 m had 2.5 times (females) or 12 times (broods) more scoter records than other lakes. 4. The abundance of large‐bodied invertebrates was greater where small fish species (mostly three‐spined sticklebacks Gasterosteus aculeatus) were more common and brown trout Salmo trutta were scarcer. 5. Results suggest two approaches to scoter conservation. At lakes used for hydro‐electricity generation, water level regimes that provide extensive shallow water should be tested to see if these benefit scoters. At lakes used for trout fishing, trout reduction by increased angling should be trialled, to see if this increases large‐invertebrate abundance and scoter use. Copyright © 2015 John Wiley & Sons, Ltd.     

The decline of endangered stone crayfish (Austropotamobius torrentium) in southern Germany is related to the spread of invasive alien species and land‐use change

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Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

The annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.     

Ex situ Culture of Colonial Marine Ornamental Invertebrates: Concepts for Domestication

The worldwide market for ornamental saltwater invertebrates supplies the needs of millions of aquarium hobbyists, as well as for public exhibition (zoos, aquaria), universities, and research institutions. The large-scale continuous collection of marine organisms is responsible, in many places, for the destruction of habitats, including coral reefs. The perceived expansion of the animal trade further threatens these fragile habitats. In the present paper, several concepts for the domestication of marine ornamental invertebrates (mainly colonial species) are discussed, offering an alternative commercial approach. The major rationale is based on future ex situ propagation, not field collections; a strategy aimed to circumvent the need for wild-harvested animals. This strategy is based on: (1) collection, settlement and metamorphosis of large numbers of larvae from marine organisms or of naturally shed germ cells under aquarium conditions, where survivorship exceeds several orders of magnitude than that in nature; (2) fragmentation of very small pieces (such as the size of a single polyp in colonial corals or blood vessel ampullae in tunicates) for the production of new colonies; (3) the development of replicates and inbred-lines from chosen ornamental species; (4) the use of cryopreservation of larvae and germ cells which will support the supply of material year-round; (5) several concepts for husbandry methods. Some benefits and deficiencies associated with the strategy for ex situ cultures are discussed, revealing its importance to the future of the trade.     

Investigation of Deep-Sea Ecosystems Using Marker Fatty Acids: Sources of Essential Polyunsaturated Fatty Acids in Abyssal Megafauna

Abyssal seafloor ecosystems cover more than 50% of the Earth’s surface. Being formed by mainly heterotrophic organisms, they depend on the flux of particulate organic matter (POM) photosynthetically produced in the surface layer of the ocean. As dead phytoplankton sinks from the euphotic to the abyssal zone, the trophic value of POM and the concentration of essential polyunsaturated fatty acids (PUFA) decrease. This results in pronounced food periodicity and limitations for bottom dwellers. Deep-sea invertebrate seston eaters and surface deposit feeders consume the sinking POM. Other invertebrates utilize different food items that have undergone a trophic upgrade, with PUFA synthesized from saturated and monounsaturated FA. Foraminifera and nematodes can synthesize arachidonic acid (AA), eicosapentaenoic acid (EPA), while some barophylic bacteria produce EPA and/or docosahexaenoic acid. FA analysis of deep-sea invertebrates has shown high levels of PUFA including, in particular, arachidonic acid, bacterial FA, and a vast number of new and uncommon fatty acids such as 21:4(n-7), 22:4(n-8), 23:4(n-9), and 22:5(n-5) characteristic of foraminifera. We suppose that bacteria growing on detritus having a low trophic value provide the first trophic upgrading of organic matter for foraminifera and nematodes. In turn, these metazoans perform the second-stage upgrading for megafauna invertebrates. Deep-sea megafauna, including major members of Echinodermata, Mollusca, and Polychaeta display FA markers characteristic of bacteria, foraminifera, and nematodes and reveal new markers in the food chain.     

The pond's shape matters: differential growth,physiological condition and survival of epibenthic Farfantepenaeus aztecus postlarvae

As a function of the water quality provided by square, circular and oval experimental ponds, the growth, survival and oxygen requirements in epibenthic postlarvae of Farfantepenaeus aztecus were analysed in relation to their routine metabolism and apparent heat increment. Temperature, oxygen concentration, pH and salinity were measured daily in two experimental ponds of each shape. The postlarvae oxygen consumption during two 24‐h cycles, their growth, physiological condition and survival and the productivity in the ponds were estimated. Low values of pH, oxygen concentration and phytobenthos productivity, and reduced postlarvae relative growth and survival were observed in the square ponds. We suggest that the latter results from a deficient water circulation related to the effect of the pond's shape on dissolved oxygen levels and, consequently, on growth and survival. The postlarvae routine metabolism, including feeding, varied between 1.91 and 2.25 mg O₂ h^?1 g^?1 wet weight, whereas the minimum oxygen concentration needed in the ponds is approximately 4.25 mg O₂ L^?1. These conditions were achieved in the oval ponds concurrent with higher survival and growth values, in which individuals distributed randomly, for which we suggest that oval‐shaped ponds could be the most adequate for the culture of this and other penaeid species.     

Non-commercial invertebrate discards in an experimental trammel net fishery

Abstract  Non-commercial invertebrate discards in an experimental trammel net fishery were studied in relation to selectivity of the gear, depth, soak time and season. Forty experimental fishing trials were carried out over a 1-year period with six combinations of small mesh (100, 120 and 140 mm) inner and large mesh (600 and 800 mm) outer panels. On average, 43.8 ± 12.2 (SD) (individuals 1000 m⁻¹ of net) of non-commercial invertebrates were discarded, accounting for 48% and 65% of the total catch and total discards by numbers, respectively. Within non-commercial invertebrates discards, the six most abundant species by number were Phallusia mammillata (Cuvier) (27.5%), Cymbium olla (L.) (13.0%), Sphaerechinus granularis (Lamarck) (11.3%), Paracentrotus lividus (Lamarck) (10.9%), Astropartus mediterraneus (Risso) (8.2%) and Astropecten aranciacus (L.) (8.1%); Echinoderms (43.1%) particularly important. The highest and lowest discard ratios were found in autumn and winter, respectively. Discards generally decreased with depth, varied considerably in relation to soak time and were not related to mesh size combinations. Trammel nets seem to be the most important gear in terms of ecological impacts on benthic invertebrates compared with other coastal fishing gears and at the depths studied (15–60 m).     

Comparison of food availability and performances of first-feeding alevins through spring with the occurrence of a flood

Climate change will increase the temperature of rivers and will lead to more extreme events, such as floods. Temperature increases and floods will likely alter the phenology of freshwater species differently and have the potential to significantly disturb prey–predator interactions. In spring, an increase in temperature triggers an increase in primary production and controls the timing of the emergence in brown trout (Salmo trutta L.). Hydrology regulates the abundance of invertebrates, which are the main food source for newborn alevins. As such, climate change may desynchronise the relationship between fish emergence and invertebrate production, resulting in a negative impact on the performance of newly emerged alevins. In the present study, we quantified the abundance of invertebrates and the performance (survival and growth) of newborn alevins in early spring (March) compared to late spring (April/May) in 8 enclosures in a semi-natural channel. In addition, we simulated a flood in 4 enclosures in late spring. Our results revealed that survival and growth of alevins in early spring were limited due to low invertebrate abundance. In late spring, there was a decrease in the survival of alevins placed in the flooded enclosures, likely due to the reduction of food availability. However, the growth of survivors increased, probably because of the increase in the abundance of Chironomidae after the flood and a reduced competition between congeners. Our results demonstrate that when emergence and flooding happen simultaneously, they can limit resources which will impact the survival and growth of young salmonids in running waters.