Killer whales (Orcinus orca) feeding on lumpfish (Cyclopterus lumpus) in northern Norway

Killer whales (Orcinus orca) in Norwegian waters have long been known to rely on Atlantic herring (Clupea harengus) as a main prey resource. However, research almost exclusively conducted at seasonal herring grounds may have biased studies away from detecting other potentially significant prey species. Since 2013, dedicated research efforts have focused on monitoring killer whale occurrence and foraging ecology throughout the year in northern Norway. This study presents results on site-fidelity of photographically identified individuals, predation records and behavioral patterns from five spring seasons (March–April) in 2014–2018 in Andfjord, northern Norway. A minimum number of 75 adult and subadult killer whales (out of a catalog of 971 individuals) returned seasonally to the study area for foraging and residency for up to six weeks. Lumpfish (or lumpsucker, Cyclopterus lumpus) was the only type of prey identified (based on molecular or visual identification) on 22 predation events from 2016 (n = 4), 2017 (n = 2) and 2018 (n = 16). Spatial group cohesion observed when foraging was a potential adaptation for efficiently hunting this prey species. These whales were also encountered at herring wintering grounds the same years, but with different group sizes. Such behavioral adaptations suggested intraannual switching between prey resources and foraging strategies.     

Short-term movements of larval and juvenile lumpfish, Cyclopterus lumpus L., in tidepools

Larval and juvenile lumpfish, Cyclopterm lumpus L., which attach to marine algae and eelgrass using a ventral sucker, were marked and recaptured in a series of experiments along Schoodic Peninsula, Maine, U.S.A. A repeat-marking experiment in 1988 indicated immigration and, possibly, emigration in tidepools. Yet, some individuals remained in the same tidepool for up to 25 days. Experiments with marked groups of fish in 1988 and 1989 revealed significant short-term residence of individual lumpfish; up to 79% of marked fish were recaptured in the same tidepool 2 days later, even after major storms. A translocated group of 34 lumpfish left the new tidepool within 1 day, but two individuals returned to the home tidepool within 6 days. Extended inhabitance of tidepools by larval and juvenile lumpfish seems to be a function of availability of food and algal cover.     

Development of bony skeleton in the ontogeny of lumpfish Cyclopterus lumpus (Cyclopteridae,Scorpaeniformes)

The development of bony skeleton is studied in the ontogeny of lumpfish Cyclopterus lumpus. In general, the sequence of appearance of the bony elements is similar to that in other teleost fishes with the exclusion of the absence of the basihyal anlage and the presence of only cartilaginous basibranchials in all examined larvae and juveniles. Bony elements of the ventral sucking disc appear very early (together with the parasphenoid, maxilla, opercle, and cleithrum), and they are characterized by rapid development. The intercalar is observed in the neurocranium of the larvae. In late larvae and in juveniles, the anlage of the medial extrascapular fused with the parietal and the lateral extrascapular attached to the pterotic are registered. C. lumpus differs from Cyclopsis tentacularis and the species of the genus Eumicrotremus in the presence of the cutting in the upper margin of the ceratohyal instead of the berycoid opening. The larvae and juveniles of C. lumpus and C. tentacularis are characterized by the presence of a reduced spiny ray at the origin of the second dorsal fin, most likely, representing a plesiomorphy of the Cyclopteridae. In the larvae of C. lumpus and C. tentacularis of a similar size, the degree of development of skeletal elements is the same, which suggests a similar developmental rate of their skeletal elements.     

Observations of growth and postspawning survival of lumpfish Cyclopterus lumpus from mark‐recapture studies

Growth and postspawning survival of lumpfish Cyclopterus lumpus are described by mark‐recapture experiments using juveniles in offshore areas in the north‐east Atlantic Ocean and spawning adults in coastal Norway and Iceland. A female fish tagged as a juvenile and recaptured as an adult matured in a period of 18 months, providing the first observation on development in a wild C. lumpus. The von Bertalanffy growth function, fitted to data from recaptured fish, was used to estimate K and L_∞ and recaptured fish spawning after a year at liberty indicated a postspawning survival of c. 10% in Iceland.     

Skin mucus proteins of lumpsucker (Cyclopterus lumpus)

Fish skin mucus serves as a first line of defense against pathogens and external stressors. In this study the proteomic profile of lumpsucker skin mucus was characterized using 2D gels coupled with tandem mass spectrometry. Mucosal proteins were identified by homology searches across the databases SwissProt, NCBInr and vertebrate EST. The identified proteins were clustered into ten groups based on their gene ontology biological process in PANTHER (www.patherdb.org). Calmodulin, cystatin-B, histone H2B, peroxiredoxin1, apolipoprotein A1, natterin-2, 14-3-3 protein, alfa enolase, pentraxin, warm temperature acclimation 65 kDa (WAP65kDa) and heat shock proteins were identified. Several of the proteins are known to be involved in immune and/or stress responses. Proteomic profile established in this study could be a benchmark for differential proteomics studies.     

Temperature preference of juvenile Arctic charr originating from different thermal environments

Temperature preference of juvenile (age 1+) Arctic charr (Salvelinus alpinus L.) originating from four arctic and sub-arctic populations (Svalbard and mainland northern Norway), representing a range of habitats with different temperature conditions, was studied by use of a shuttle-box system which allowed individual fish to control their environmental temperature. Based on the assumption that adaptations to long-lasting differences in thermal environments would affect temperature preference, we expected that Arctic charr from the high arctic Svalbard would prefer a lower temperature than the charr from two well-studied sub-arctic mainland lakes (i.e. one anadromous charr population from Storvatn, Hammerfest and two sympatric resident charr morphs from Fjellfrøsvatn, Målselv). There were, however, no significant differences in temperature preference among the four populations after 24 h exposure to the shuttle-box system, although the charr from the omnivore upper-water sympatric morph of Fjellfrøsvatn used significantly longer time to reach a stable thermal preferendum than the fish of the other populations. The average temperature preference at the end of the trials ranged between 10.9 and 11.6 °C among the populations. The lack of population differences suggests that temperature preference is not a polymorphic trait under strong selection in Arctic charr.     

Phenodeviants of the Lumpfish Cyclopterus lumpus (Cyclopteridae) and Their Survival

Journal of Ichthyology - Deviations in the development of the caudal peduncle in the lumpfish Cyclopterus lumpus are described. Data on abiotic and biotic conditions of lumpfish’s existence...     

Sublethal effects of a new antifouling candidate on lumpfish (Cyclopterus lumpus L.) and Atlantic cod (Gadus morhua L.) larvae

Abstract

Sublethal effects of medetomidine, a new generation antifouling compound, on lumpfish (Cyclopterus lumpus L.) and cod (Gadus morhua L.) larvae were examined. The effects on respiration rate and on colour adaptation of newly hatched larvae were assessed after 24–96 h exposure. Exposure of lumpfish larvae to the experimental concentrations resulted in a significant decrease in respiration rate (Lowest Observed Effect Concentration (LOEC) = 5–10 nM) and in the percentage of dark larvae (LOEC = 4 nM). However, no effects on respiration rate of cod larvae were detected. In addition to lumpfish larvae being affected at low concentrations of medetomidine, a reversibility of the effects was observed when 96 h-exposed larvae were incubated in clean seawater for 24–48 h. Considerations relating to the future commercialisation of medetomidine for antifouling purposes are discussed.     

Sublethal effects of a new antifouling candidate on lumpfish (Cyclopterus lumpus L.) and Atlantic cod (Gadus morhua L.) larvae

Sublethal effects of medetomidine, a new generation antifouling compound, on lumpfish (Cyclopterus lumpus L.) and cod (Gadus morhua L.) larvae were examined. The effects on respiration rate and on colour adaptation of newly hatched larvae were assessed after 24-96 h exposure. Exposure of lumpfish larvae to the experimental concentrations resulted in a significant decrease in respiration rate (Lowest Observed Effect Concentration (LOEC) = 5-10 nM) and in the percentage of dark larvae (LOEC = 4 nM). However, no effects on respiration rate of cod larvae were detected. In addition to lumpfish larvae being affected at low concentrations of medetomidine, a reversibility of the effects was observed when 96 h-exposed larvae were incubated in clean seawater for 24-48 h. Considerations relating to the future commercialisation of medetomidine for antifouling purposes are discussed.     

On the spatial relationship between the spawning and feeding parts of the range of lumpfish Cyclopterus lumpus (Cyclopteridae) in the Barents Sea and adjacent waters (according to results of analysis of the size composition similarity)

Results of analysis of similarity of size series of mature females of the lumpfish Cyclopterus lumpus collected on the spawning grounds in the Barents and Norwegian seas (Russian and Norwegian coasts), as well as in the areas of its feeding, are provided. The trajectories of feeding migrations of lumpfish in the southern part of the Barents Sea have been revealed. A clinal decrease in the average length of females in the range from west to east is shown. The area of feeding aggregations of lumpfish spawning off the Russian coast is distinguished. The boundaries of the census water area used to assess the commercial stock of lumpfish and to determine the values of its possible catch off the coast of Murmansk are specified.     

Characteristics of a proteinase from ovarian fluid of the lumpsucker (Cyclopterus lumpus L.)

1. A proteinase has been isolated from the ovarian fluid of the lumpsucker (Cyclopterus lumpus). 2. The enzyme was purified essentially to homogeneity by a one step purification procedure using anion-exchange chromatography. 3. The mol. wt of the denatured enzyme is approximately 20,000 as judged by SDS-polyacrylamide gel electrophoresis. 4. The enzyme is inhibited by serine-proteinase inhibitors and acts in the manner of a trypsin-type proteinase both with respect to specific peptide substrates and enzyme inhibitors. 5. The lumpsucker proteinase exhibits low general proteolytic activity but acts effectively on the specific chromogenic peptide substrates.     

First record of Cyclopterus lumpus L., 1758 (Osteichthyes: Cyclopteridae) in the Mediterranean Sea

The Atlantic lumpsucker Cyclopterus lumpus (343 mm total length) is recorded for the first time from the Mediterranean Sea. The specimen was collected in the night between 16 and 17 September 2004 off Molunat Bay, Croatia, southern Adriatic Sea. This record may present a case of a vagrant specimen.     

Temperature and the energetics of development in the house cricket (Acheta domesticus)

The influence of rearing temperature on the energetics of development was investigated in house crickets (Acheta domesticus). Crickets raised at 25 degrees C grew slower (0.51 mg d(-1), dry mass basis) and took longer to develop (119 d) but obtained a greater adult body mass (61 mg, dry mass) than crickets reared at 28 degrees C (0.99 mg d(-1), 49 d, 48 mg). Total metabolic energy consumed during development at 25 degrees C (1351 J) was twice that at 28 degrees C (580 J) primarily because of the longer development period, and as a consequence the specific net cost of growth was much greater for crickets reared at 25 degrees C (22.1 kJ g(-1)) than 28 degrees C (11.9 kJ g(-1)).     

Host plant and habitat preference of the endangered Euphydryas maturna (Lepidoptera: Nymphalidae): evidence from northern Europe

1. The aim of the present study was to evaluate host plant and habitat preferences in the Estonian populations of Euphydryas maturna, a regionally polyphagous but often locally specialised butterfly endangered in most parts of its European range. 2. Laboratory trials suggested that Fraxinus excelsior, Viburnum opulus and Melampyrum pratense are plants recognised by ovipositing females as potential hosts. These plants also supported development of the larvae, with the poorest growth performance on M. pratense. 3. Both a transect count‐based habitat occupancy analysis and a country‐wide landscape occupancy analysis revealed the abundance of F. excelsior as the primary determinant of the occurrence of E. maturna. In contrast, the occurrence of E. maturna was not associated with habitats colonised by M. pratense. 4. The results suggest that European ash, F. excelsior, is the main, if not the only, host plant of E. maturna in Estonia. The use of V. opulus cannot be excluded, although, due the relative scarcity of this plant, an important role for it as a determinant of the distribution of E. maturna is unlikely. Melampyrum pratense is not likely an alternative host of E. maturna in Estonia, which contrasts with the situation in neighbouring Finland. 5. This study adds to the evidence of geographical differences in host specialisation in melitaeine butterflies. The results imply that conservation actions should focus on securing the favourable status of the locally used host plant; the populations of F. excelsior are currently threatened by a fungal disease, ash dieback.     

Thermal tolerance and preference of the Indian catfish Heteropneustes fossilis

Synopsis The catfish Heteropneustes fossilis tolerates a wide range of temperatures. The minimal (7.9°C) and maximal (39.8°C) lethal temperature values obtained during summer are higher than the minimal (4°C) and maximal (37.7°C) lethal temperature values obtained during winter; gradual heating or cooling versus abrupt exposure to various temperatures did not produce significant differences. Catfish acclimated to temperatures of 28° (summer) or 16°C (winter) finally selected temperatures ranging from 31.3° to 32° C, when placed in a temperature gradient of 15° to 35° C. Catfish avoid temperatures below 25° C regardless of seasonal acclimatization.