mtDNA sequences of Sphyraena viridensis (Perciformes: Sphyraenidae) from Italy: insights into historical events and the phylogeny of the genus

The yellowmouth barracuda, Sphyraena viridensis, is a Mediterranean native species whose exact distribution is uncertain due to a long‐term taxonomic confusion with Sphyraena sphyraena. Records of this species in the Mediterranean Sea have recently increased, and a northwards expansion of its distribution has been suggested. Three mtDNA regions, namely cytochrome oxidase I, cytochrome b and the control region, were analysed in S. viridensis samples from Italian coastal regions to provide molecular markers useful in species identification, in phylogenetic analysis and in detecting the distribution of genetic variability of the yellowmouth barracuda in this area. The data clearly distinguish S. viridensis from S. sphyraena and the other four (one native and three Lessepsian) Mediterranean Sphyraena species and identify two clearly distinct lineages that diverged during the Pleistocene but are currently panmictic in the investigated area. Both lineages retain signatures of historical population expansion. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 635–641.     

First record of the Sphyraena chrysotaenia (Klunzinger, 1884) (Pisces, Sphyraenidae) from the Adriatic Sea

One specimen of the obtuse barracuda Sphyraena chrysotaenia is recorded for the first time from the Adriatic Sea.     

Heavy metals, lipid peroxidation, and ciguatera toxicity in the liver of the caribbean barracuda (Sphyraena barracuda)

Human consumption of over 400 species of tropical fish containing polyether toxins (e.g. ciguatoxins, maitotoxins) causes ciguatera fish poisoning. The Caribbean barracuda (Sphyraena barracuda) is one of the most potent ciguatoxic fish. The objective of this study was to determine whether toxicity of 14 barracuda livers was correlated with lipid peroxidation. A significant correlation (p = 0.015, Pearson’s correlation) between lipid peroxidation and toxicity of barracuda liver was found. Because iron and copper are well-known catalysts of hydroxyl radical production and lipid peroxidation in biological systems, the correlation between the concentrations of these metals in barracuda liver and lipid peroxidation and toxicity was also investigated. Cadmium was significantly correlated (p = 0.014) with the toxicity of barracuda livers. This study provides the first data concerning the concentration of iron, copper, and cadmium in the liver of the Caribbean barracuda. Of the three metals studied in barracuda liver, iron was the most abundant, followed by copper and cadmium. Lipid peroxidation was highly variable and detected in five (36%) of the liver samples. Lipid peroxidation was not statistically significantly correlated (p > 0.05) with concentrations of iron, copper, and cadmium in barracuda liver. Collectively, these findings provide additional evidence that lipid peroxidation can be a mechanistic component of ciguatera toxicity in the Caribbean barracuda.     

Life‐history traits of flatfish in the Northeast Atlantic and Mediterranean Sea

Flatfishes are poorly represented in published literature regarding life‐history strategies, as opposed to some other taxonomic groups of teleost fish. The present work constitutes an integrated approach to life‐history traits of the Order Pleuronectiformes occurring in the Northeast Atlantic and Mediterranean Sea. Data was exhaustively collected for several species of the families Scophthalmidae, Pleuronectidae, Bothidae and Soleidae, namely life‐history parameters from the von Bertalanffy growth model (L_∞ and k), absolute fecundity and size at maturity (L_m), as well as ecological and environmental data, with regard to the species and their area of occurrence. An inter‐specific ordination analysis based on life‐history parameters and environmental factors revealed distinct patterns of life‐history strategies, not necessarily grouped by phylogenetic affinities. Species with a more northern range of distribution were distinguishable from those with southern affinities by showing larger sizes, lower growth rates, earlier spawning, shorter spawning periods and higher fecundity. Possible environmental causes for these traits are discussed. Intra‐specific analyses were also performed and were generally in agreement with other authors, yet some disagreement was found for the inter‐specific analysis.     

Rapid response of invasive round goby (Neogobius melanostomus) (Pallas, 1814) to an environmental perturbation demonstrated in reproductive parameters of females

Plasticity in life‐history traits appears to be very important for adaptation of invasive species to a novel environment. Predictable changes in life‐history traits have been observed in the progression of invasions in several fish species. Nevertheless, the novel environment of the invaded areas can pose a challenge to the invaders caused by sudden perturbations in the ecological conditions. The aim of this study was to examine whether a sudden environmental disruption would reflect in significant changes in the reproductive parameters of the females of an invasive round goby (Neogobius melanostomus) population. Samples were collected from the middle section of the River Danube (Bratislava, Slovakia) from the 2008 post‐spawning period to the end of spawning in 2010. The results support the prediction that after a strong environmental perturbation, the females increase their absolute as well as relative numbers of oocytes and their real absolute fecundity; the differences in all of these parameters were statistically significant. Another strong environmental disruption occurred in June 2010, although the response differed from that of 2009. In 2009, the females responded by increasing their oocyte numbers; in 2010, they extended their reproductive season by producing an extra batch of eggs. This can be explained by the different timing of the sudden perturbations. In summation, a coincidence between the environmental perturbations and the significant changes in their reproductive traits was found in the round goby females in the two subsequent years. This indicates that the round goby can respond rapidly to environmental disruptions, and that such reproductive flexibility likely helps the species in its successful invasions.     

Twilight activity patterns and angling vulnerability of yellowmouth barracuda (Sphyraena viridensis Cuvier, 1829), a range-expanding thermophilic fish

Among the thermophilic fishes that have become established in the north-western Mediterranean as a consequence of sea warming, the yellowmouth barracuda (Sphyraena viridensis Cuvier, 1829) appears to be one of the most successful and abundant in the coastal rocky environment, having increasingly become the object of recreational and commercial exploitation in the study area. Lure-fishing sessions were carried out from May 2016 to November 2018 in the Catalan Sea (NE Spain) at dawn and dusk, with the aim of providing new insight into the behavioural, spatial and feeding ecology and vulnerability to angling of this poorly known species. Generalized mixed-effects linear models showed that S. viridensis is a crepuscular inshore dweller, whose vulnerability to angling is significantly influenced by solar and lunar light intensities, being highest in the pre-spawn and spawning periods. Asymmetries between dawn and dusk activity patterns were detected, evidently related to a drop in aggressiveness at dusk following the spawning period. The simple study design adopted may be applied to other contexts, aiming to the recognition of several levels of fish vulnerability to angling.     

The life history and decline of the threatened Australian frog,Litoria raniformis

A popular idea amongst ecologists last century was that animals which exploit dynamic environments often display ‘fast’ life history strategies (high fecundity, rapid growth and maturation, and low or variable adult survival rates) relative to those which occupy more stable environments. Whilst the underlying theory has been discredited, the categorization remains of interest, because species with ‘fast’ life history traits are thought to be more robust to human‐induced environmental change than those with ‘slow’ life history traits. We examined the life history traits of the endangered Australian frog Litoria raniformis, to determine whether it displays ‘fast’ life history traits (like its sister species L. aurea and L. castanea), and to assess the role of these traits in the decline of this species. Mark‐recapture data confirmed that L. raniformis displays rapid growth and maturation. The data also suggest that L. raniformis displays relatively low adult survival rates. We propose that the ‘fast’ life history traits of this species are adaptive to metapopulation dynamics. In turn, we suggest that the rapid decline of L. raniformis may have resulted from metapopulation collapse, driven ultimately by habitat loss, degradation and fragmentation, and proximately by severe stochastic perturbations.     

Growth and reproduction of the non‐native icefish Neosalanx taihuensis Chen, 1956 (Salangidae) in a plateau lake,southwestern China

Growth, reproduction and abundance traits of the invasive icefish Neosalanx taihuensis Chen, 1956 were investigated monthly from July 2009 to May 2011 in Lake Erhai on the Yunnan‐Guizhou Plateau, south‐western China, in order to explore the changes in life‐history traits after translocation. The results indicated that the icefish exhibited obvious plasticity in growth and reproduction traits. Growth of the fish in Lake Erhai was faster than that in native waters and in other translocated reservoirs. By fitting the von Bertalanffy growth model to the data, it was estimated that icefish obtain an asymptotic size of 96.12 mm, a K of 1.61, and a t₀ of ‐0.26; the calculated overall growth performance index φ′ was 4.17. The strategy of reproduction changed from multiple‐ to single‐spawning. The spawning period was from October to December with the absolute and relative fecundities of 1250 ± 169 eggs per ind and 2557 ± 245 eggs per g, respectively. Plasticity in icefish growth and reproduction in Lake Erhai greatly facilitated its population establishment, making it one of the most abundant fish species. The icefish invasion in the lake may be one of the reasons for the decrease or extinction of native fish species populations, and some measures for the control of this invasive fish are suggested.     

Environmental drivers of diurnal visits by transient predatory fishes to Caribbean patch reefs

Video cameras recorded the diurnal visitation rates of transient (large home range) piscivorous fishes to coral patch reefs in The Bahamas and identified 11 species. Visits by bar jack Caranx ruber, mutton snapper Lutjanus analis, yellowtail snapper Ocyurus chrysurus, barracuda Sphyraena barracuda and cero Scomberomorus regalis were sufficiently frequent to correlate with a range of biophysical factors. Patch‐reef visitation rates and fish abundances varied with distance from shore and all species except S. regalis were seen more frequently inshore. This pattern is likely to be caused by factors including close proximity to additional foraging areas in mangroves and on fore‐reefs and higher abundances close to inshore nursery habitats. Visitation rates and abundances of C. ruber, L. analis, O. chrysurus and S. regalis also varied seasonally (spring v. winter), possibly as fishes responded to temperature changes or undertook spawning migrations. The abundance of each transient predator species on the patch reefs generally exhibited limited diurnal variability, but L. analis was seen more frequently towards dusk. This study demonstrates that the distribution of transient predators is correlated spatially and temporally with a range of factors, even within a single lagoon, and these drivers are species specific. Transient predators are considered an important source of mortality shaping reef‐fish assemblages and their abundance, in combination with the biomass of resident predators, was negatively correlated with the density of prey fishes. Furthermore, transient predators are often targeted by fishers and understanding how they utilize seascapes is critical for protecting them within reserves.     

Feeding ecology of indigenous and non-indigenous fish species within the family Sphyraenidae

The feeding ecology of two common indigenous (Sphyraena viridensis and Sphyraena sphyraena) and one abundant non-indigenous sphyraenid species, Sphyraena chrysotaenia, of Indo-Pacific Ocean origin, was investigated in an area of the eastern Mediterranean Sea. The stomach contents of 738 individuals of varying size, collected during the period December 2008 to August 2009, were examined. The dietary analyses revealed that all three species were specialized piscivores with a diet consisting of >90% fish, both by number and mass. Concurrent sampling of the fish assemblage made it possible to calculate selectivity as well as diet breadth and overlap of these strict piscivores. Even though several prey species were found in the stomachs of the three predators examined, selectivity towards Atherina boyeri was highly significant. For all species examined, >70% of the diet by mass was made up by three indigenous species of commercial value: Spicara smaris, Boops boops and A. boyeri. Diet breadth and size of prey increased with increasing body size for all predators. With increased body size, the diet overlap between indigenous and non-indigenous species decreased. This could be attributed to increased diet breadth and the specific life-history characteristics of indigenous species developing into larger individuals. During winter, the condition factor of the non-indigenous species was significantly lower than that of the indigenous, indicating that winter conditions in the Mediterranean Sea may limit its further expansion north and westward. With this study, the gap in knowledge of the feeding preferences of the most abundant piscivorous species found in coastal areas of the study region is filled. Additionally, the results indicate that non-indigenous species familial affiliation to indigenous ones does not facilitate invasion success.     

Identifying individual great barracuda Sphyraena barracuda using natural body marks

Natural body marks on Sphyraena barracuda were recorded with digital images to identify individual fish. Over 18 months, 60 fish were photographed in situ , eight of which were re-photographed at later dates. Re-photographed fish were all large adults (>70 cm total length) and were all seen within 200 m of the site where they were originally observed 10–318 days prior. Over the same period and area, 116 fish were tagged using T-bar tags, yet none of these fish were recaptured. Natural body marks are thus an effective means of identifying and monitoring behaviour of individuals.     

The response of life‐history traits to a new species in the community: a story of Drosophila parasitoids from the Rhône and Saône valleys

In the present study, we investigated the evolution of life‐history traits in the main species of a community, after the arrival of a new competitor. Two parasitoid species, Leptopilina heterotoma and Asobara tabida, are present throughout the Rhône and Saône valleys, whereas a third species, Leptopilina boulardi, is slowly extending its distribution northwards. In the presence of L. boulardi, competing parasitoids experience a higher mortality and lower host availability. Resources should thus be re‐allocated between traits according to these new factors. We compared life‐history traits of populations of L. heterotoma and A. tabida in areas with and without L. boulardi. As predicted by both Price's balanced mortality hypothesis and the theory of life‐history traits, we found that investment in reproduction is higher in southern populations for both native species, coupled with higher travelling abilities. However, only A. tabida paid their higher fecundity by a lower longevity. The absence of a clear trade‐off between these traits in L. heterotoma may be explained by a lower metabolic rate in southern populations. These results highlight the importance of the community change over climate in the evolution of life‐history traits in this parasitoid community. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Phenotypic Plasticity in the Reproductive Behavior of Female Sand Tilefish, Malacanthus plumieri

Female sand tilefish (Malacanthus plumieri) inhabiting a deep channel in the fringing reef at Glover's Atoll, Belize (channel females) spawned planktonic eggs more frequently than those occupying the shallow sand‐rubble slopes adjacent to patch coral reefs inside the atoll lagoon (reef‐slope females). We tested five non‐exclusive hypotheses to explain habitat differences in female spawning frequency. We found no evidence that spawning frequency variation was a consequence of differences in food availability, variation in male fertility, or the intensity of predation on spawned eggs. On reef slopes, barracuda stalked tilefish near their benthic burrows, whereas these piscivores attacked channel tilefish by diving suddenly from higher in the water column. Differences in the hunting behavior of barracuda suggested that the behavior of tilefish females might be influenced by temporal variation in predation risk (risk allocation hypothesis). Consistent with this hypothesis, reef‐slope females had a much higher frequency of retreats to burrows in response to barracuda, spent more time burrowing and ventured less far from these refugia in response to a simulated predatory threat. As predicted by the risk allocation hypothesis, reef‐slope females also had lower and more variable frequencies of foraging bites, and shorter and more variable travel distances to forage than channel females. Estimated mortality from predation was over nine times higher in channel tilefish. Consistent with the hypothesis that investment in current vs. future reproduction is influenced by rates of adult mortality (mortality risk hypothesis), channel females invested more supplemental energy in egg production whereas reef‐slope females invested more in growth. Our results indicate that behavioral and life‐history traits of female tilefish show phenotypic plasticity depending upon the nature and intensity of localized predation risk.     

Comparative demography of commercially important parrotfish species from Micronesia

Fishery‐independent sampling was used to determine growth patterns, life span, mortality rates and timing of maturation and sex change in 12 common parrotfishes (Labridae: tribe Scarinae) from five genera (Calotomus, Cetoscarus, Chlorurus, Hipposcarus and Scarus) in Micronesia. Interspecific variation in life‐history traits was explored using multivariate analysis. All species displayed strong sex‐specific patterns of length‐at‐age among which males reached larger asymptotic lengths. There was a high level of correlation among life‐history traits across species. Relationships between length‐based and age‐based variables were weakest, with a tenuous link between maximum body size and life span. Cluster analysis based on similarities among life‐history traits demonstrated that species were significantly grouped at two major levels. The first grouping was driven by length‐based variables (lengths at maturity and sex change and maximum length) and separated the small‐ and large‐bodied species. Within these, species were grouped by age‐based variables (age at maturity, mortality and life span). Groupings based on demographic and life‐history features were independent of phylogenetic relationships at the given taxonomic level. The results reiterate that body size is an important characteristic differentiating species, but interspecific variation in age‐based traits complicates its use as a life‐history proxy. Detailed life‐history metrics should facilitate future quantitative assessments of vulnerability to overexploitation in multispecies fisheries.     

The effect of multi‐species host density on superparasitism and sex ratio in a gregarious parasitoid

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Life‐history traits of the common snook Centropomus undecimalis in a Caribbean estuary and large‐scale biogeographic patterns relevant to management

The ecology of common snook Centropomus undecimalis in Amatique Bay, a tropical estuary in eastern Guatemala, was investigated and life‐history traits were used to conduct a meta‐analysis of the species from Florida to Brazil. The reproduction cycle of C. undecimalis in Amatique was strongly related to the precipitation cycle, with a lag of 2 months. Spawning occurred from April to November with a peak spawning after the onset of the summer rains. Protandric sex reversal occurred early in the dry season (December) before somatic recovery from spawning. The growth cycle preceded that of body condition by c. 1 month, and was out of phase with the reproductive cycle. Growth was fast, as many individuals reached >70% of the maximum observed total length (L_T, 102 cm) after 3 years. Sex transition occurred within a relatively narrow L_T range (70–79 cm), but over a wide range of ages, indicating plasticity in this respect. The meta‐analysis indicated a latitudinal‐temperature gradient in life‐history traits, as well as different seasonal patterns relative to temperature and hydrographical cycles. Centropomus undecimalis from cooler winter waters (e.g. Florida) reach larger maximum L_T and L_T at sex change, as well as greater gonado‐somatic indices and longer life spans. Further, increased fishing mortality results in younger age at sex reversal and male predominance in the populations compared. Recognition of large‐scale biogeographic patterns in this important, but little studied, fish species helps in the formulation of management advice in other areas of its occurrence.     

Life history influences the vulnerability of New Zealand galaxiids to invasive salmonids

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Influence of streamflow on spawning‐related movements of golden perch Macquaria ambigua in south‐eastern Australia

In this study, linkages were examined between movement and spawning behaviour for golden perch Macquaria ambigua in a lowland river by integrating acoustic telemetry and egg and larval drift sampling over 4 years. Movement was strongly seasonal, being most prevalent during the spawning season (spring to early summer), and occurred primarily downstream into the lower river reaches during elevated flows. A very strong association was found between the occurrence of spawning and long‐distance M. ambigua movement. The results also revealed that targeted environmental water allocation can promote movement and spawning of this species. By integrating multiple analytical approaches and focusing on key life‐history events, this study provides an improved picture of the life history and flow requirements of M. ambigua. The findings can help guide the development of effective environmental flow recommendations.     

Reciprocal distribution of two congeneric trees, Betula platyphylla var. japonica and Betula maximowicziana, in a landscape dominated by anthropogenic disturbances in northeastern Japan

Aim Information has been compiled on disturbance regimes and the life‐history characteristics of Betula platyphylla var. japonica (Miq.) Hara and B. maximowicziana Regel to investigate the impact of humans on the present distribution patterns of these two congeneric tree species. Location The study area is in the central region of the northern Kitakami Mountain Range, located in the northeast of Honshu Island, Japan. Methods First, the present distributions of B. maximowicziana and B. platyphylla var. japonica were mapped at the landscape scale. To examine the factors affecting the distribution patterns, topographic features and past land use were taken into account. Second, life‐history traits of both species were clarified at various growth stages either by fieldwork or through a literature search. Previous studies have provided some information on seed production, seed dispersal, seedling dynamics, sprouting, and growth. In the present study, field observations and experiments were conducted regarding seed‐bank formation, size and age at reproduction, and the life span of canopy trees. Results Betula platyphylla var. japonica and B. maximowicziana were spatially segregated in the studied landscape (14,000 ha). The distribution of each species was correlated more strongly with land use at the beginning of the twentieth century than with site environmental factors such as altitude or slope angle. Betula platyphylla var. japonica was distributed more frequently on former grasslands, whereas B. maximowicziana was almost exclusively limited to past old‐growth forests. As typical pioneers, the two species showed similar life‐history traits but differed in several critical points. Betula platyphylla var. japonica has a vigorous sprouting ability, which might increase its resistance to burning and logging, whereas B. maximowicziana forms a persistent seed bank in the soil, indicating an advantage in regenerating in disturbances found in forest communities. Other critical differences were detected in age‐related characteristics such as minimum age of reproduction and life span. Main conclusions The earlier reproductive maturity and the shorter life span of B. platyphylla var. japonica indicate a shorter population cycle than that for B. maximowicziana. The latter would be excluded from grasslands that were burned frequently, as a result of the longer time span before initial reproduction and its poor sprouting ability. In contrast, B. platyphylla var. japonica would be excluded from old‐growth forests, where disturbance was infrequent, owing to its shorter life span and lack of a persistent seed bank.     

Allodidymozoon gasterale n. sp. and A. operculare Madhavi, 1982 (Didymozoidae) from the barracuda Sphyraena obtusata Cuvier in Kuwait Bay

Allodidymozoon gasterale n. sp. and A. operculare Madhavi, 1982 (Digenea: Didymozoidae) were found encysted in pairs in the stomach wall and head muscles, respectively, of the yellow-finned barracuda Sphyraena obtusata in Kuwait Bay, northern Arabian Gulf. The new species can be distinguished from congeneric species by the site of infection, the arrangement of the two individuals in the cyst, the numbers of ovarian and vitelline terminal branches, the size and shape of testes, and the presence of a seminal receptacle. The two didymozoids were examined under the scanning electron microscope.