Geographical variation in shell shape of the pod razor shell Ensis siliqua (Bivalvia: Pharidae)

The present study assessed the existence of variation in the shell shape of the pod razor shell (Ensis siliqua) throughout its distributional range in the north-eastern Atlantic. Shells of E. siliqua caught at seven collecting sites (three in Portugal, three in Spain and one in Ireland) were studied by geometric morphometric methods, using both landmark- and contour-based methods. Both approaches (landmarks inside the valves and shell outline) discriminated the shells from Aveiro (centre of Portugal) and Strangford Lough (Ireland) from those caught in the nearby localities (remaining Portuguese and Spanish sites, maximum distance of 550 km by sea). Landmark analysis revealed that shells from Aveiro were more similar to shells from Ireland (~1,500 km far away). Contour analysis revealed that shells from Aveiro had a shape with a comparatively larger height-to-width ratio, whereas shells from Ireland showed a slightly more curved outline than in the remaining sites. Landmark- and contour-based methods provided coherent complementary information, confirming the usefulness of geometric morphometric analyses for discerning differences in shell shape among populations of E. siliqua. A brief review of previous applications of geometric morphometric methods to modern bivalve species is also provided.     

Marine plant harvest in Portugal

This work brings together the scattered information on marine plant harvests and the colloid extraction industry in Portugal, as an initial contribution to the improvement of resource management. The first phase of exploitation of marine plant resources started prior to the 14th century, with the gathering and sale of storm-tossed seaweeds for fertilizer. The harvest of seagrasses and algae at Ria de Aveiro was of great economic importance. The second phase of resource exploitation began with the wider scale harvest of agarophyte species for colloid extraction. Portugal is at present the third largest harvester of the agarophytes Gelidium and Pterocladia (2500 t annually), and it is the fifth largest agar producer (350 t annually). Other colloid-producing species, including Chondrus crispus and Mastocarpus stellatus, are also harvested for export. The total agarophyte landings, agar production and income from agar exports is far below the maximum levels attained in the early 1970s. The status of stocks in each different harvest zone on the continental coast and the Azores is examined. Although there is an effective management structure for the Portuguese marine plant resource, research is needed to provide a sound biological basis for management. author for correspondence     

Some population parameters of Ruditapes philippinarum (Bivalvia,Veneridae) on the southern coast of the Marmara Sea,Turkey

Ruditapes philippinarum, a venerid clam, is a dominant species in the sandy and muddy areas in the coastal waters of the Marmara Sea. Intensive commercial harvesting of this species is conducted in these regions. We studied the population dynamics of R. philippinarum on the southern coast of the Marmara Sea (Band?rma). Samples were collected on a monthly basis between September 2012 and August 2013. Seasonal von Bertalanffy growth parameters using the length–frequency distribution of R. philippinarum were estimated at L _∞ = 67.50 mm and K = 0.33 year^?1, and the seasonal oscillation in growth rate was 0.53. The slowest growth period was in January. The growth performance index and potential lifespan were 3.182 and 8.06 years, respectively. The growth relationship was confirmed to have a positive allometric pattern. The average total mortality rate was estimated to be 0.777 year^?1, whereas the natural and fishing mortality rates were 0.539 and 0.238 year^?1, respectively. The current exploitation rate of R. philippinarum was 0.306. The recruitment pattern peaked during June–August, and spawning occurred between May and August. The results of this study provide valuable information on the status of R. philippinarum stocks.     

Influence of latitudinal variation in environmental gradients and population structure on the demography of a widespread pelagic fish, <Emphasis Type="Italic">Arripis trutta</Emphasis> (Forster, 1801)

Knowledge of the influence of both spatial and temporal environmental gradients on life history traits and population demographics is a critical requirement in the management of exploited fish populations. This study examined variation in the demographics of Arripis trutta, an economically-important pelagic fish species with a broad latitudinal distribution in the waters of coastal south-eastern (SE) Australia, a region dominated by the influence of the East Australian Current (EAC). A validated ageing protocol was first developed using sectioned sagittal otoliths, which in turn permitted examination of latitudinal variation in A. trutta growth, size compositions and age compositions. The von Bertalanffy growth function parameters for A. trutta in SE Australia were estimated to be L _∞?=?63.20?±?0.37 cm fork length (FL), k?=?0.26?±?0.01 yr^?1 and t _o?=??0.14?±?0.03 yr, with a maximum estimated age of 12.7 years. Growth was shown to be faster with decreasing latitude likely due to a simple relationship with the latitudinal gradient in water temperature; fastest growth occurring in northern NSW and slowest growth occurring in Tasmania. Latitudinal patterns in growth were remarkably similar to those previously reported for this species, despite age being estimated using scale readings some 40 years ago. This consistency in latitudinal growth patterns of a temperate fish can be attributed to the life history-related movements undertaken by A. trutta in this region. This temporally-consistent movement pattern is supported by the spatial gradient in the size and age composition of A. trutta sampled from different latitudes in both the current and historical research, whereby numbers of large and old fish increase progressively from Tasmania to northern NSW. These results highlight the need to consider the potential for spatial size- or age-structuring in the development of sampling designs and interpretation of results for any study examining spatial or temporal variation in demographic parameters of exploited fish populations.     

Age and growth, mortality, reproduction and relative yield per recruit of the bogue, Boops boops Linné, 1758 (Sparidae), from the Algarve (south of Portugal) longline fishery

Samples of Boops boops ranging from 7.4 to 30.5 cm were obtained mainly by longline, supplemented by beach seining in the Ria Formosa lagoon, and by market sampling in the Algarve (southern Portugal). The macroscopic analyses of the gonads and the gonad somatic index showed that the south coast of Portugal B. boops spawn mainly from late winter to spring, between February and May. The length at first maturity was similar for males and females and the value for both sexes combined was estimated to be 15.22 cm, corresponding to an age range of 1–3. Age was determined by reading growth bands on otoliths. Age determination was validated by marginal increment analysis. The estimated parameters were L_∞ = 28.06, K = 0.22 and t₀ = ?1.42. Mortality rates were calculated for fish captured with longlines, and the estimated parameters were M = 0.33, Z = 1.04 and F = 0.71. Relative yield per recruit analysis and sensitivity analysis showed that the resource is moderately exploited. From the perspective of sustainability, these results provide support for the use of longlines as a gear that is among the least harmful for species such as the bogue.     

Do the maximum sizes,ages and patterns of growth of three reef‐dwelling labrid species at two latitudes differ in a manner conforming to the metabolic theory of ecology?

The size and age data and patterns of growth of three abundant, reef‐dwelling and protogynous labrid species (Coris auricularis, Notolabrus parilus and Ophthalmolepis lineolata) in waters off Perth at c. 32° S and in the warmer waters of the Jurien Bay Marine Park (JBMP) at c. 30° S on the lower west coast of Australia are compared. Using data for the top 10% of values and a randomization procedure, the maximum total length (L_T) and mass of each species and the maximum age of the first two species were estimated to be significantly greater off Perth than in the JBMP (all P < 0·001) and the maximum ages of O. lineolata in the two localities did not differ significantly (P > 0·05). These latitudinal trends, thus, typically conform to those frequently exhibited by fish species and the predictions of the metabolic theory of ecology (MTE). While, in terms of mass, the instantaneous growth rates of each species were similar at both latitudes during early life, they were greater at the higher latitude throughout the remainder and thus much of life, which is broadly consistent with the MTE. When expressed in terms of L_T, however, instantaneous growth rates did not exhibit consistent latitudinal trends across all three species. The above trends with mass, together with those for reproductive variables, demonstrate that a greater amount of energy is directed into somatic growth and gonadal development by each of these species at the higher latitude. The consistency of the direction of the latitudinal trends for maximum body size and age and pattern of growth across all three species implies that each species is responding in a similar manner to differences between the environmental characteristics, such as temperature, at those two latitudes. The individual maximum L_T, mass and age and pattern of growth of O. lineolata at a higher and thus cooler latitude on the eastern Australian coast are consistent with the latitudinal trends exhibited by those characteristics for this species in the two western Australian localities. The implications of using mass rather than length as the indicator variable when comparing the maximum sizes of the three species and the trends exhibited by the instantaneous growth rates of those species at different latitudes are explored. Although growth curves fitted to both the L_T and masses at age for the males of each species lay above those for their females, this would not have influenced the conclusions drawn from common curves for both sexes.     

Age, growth and mortality of painted comber, Serranus scriba (Linnaeus, 1758), in the Trogir Bay area (eastern mid-Adriatic)

Population dynamics of 1482 specimens of painted comber, Serranus scriba (Linnaeus, 1758), caught in the Trogir Bay area (eastern mid‐Adriatic) from June 2001 to May 2002 were studied to provide information on age, growth, length–weight relationship, mortality and exploitation rate of the species’ stock. Annuli on otholiths indicated the presence of seven age‐classes. Obtained von Bertalanffy growth parameters were: L_∞ = 30.36 cm, K = 0.192 year^?1 and t₀ = ?0.366.     

Reliability-based life cycle assessment for future solid waste management alternatives in Portugal

Background, aim, and scope  

This paper presents a study related to the application of the reliability-based life cycle assessment (LCA) to assess different alternatives for solid waste management in the Setúbal peninsula, Portugal. The current system includes waste collection, transport, sorting, recycling, and mechanical and biological treatment (MBT) by means of aerobic treatment and landfill. In addition, some future expansion plans are discussed.     

Slow growth of the overexploited milk shark Rhizoprionodon acutus affects its sustainability in West Africa

Age and growth of Rhizoprionodon acutus were estimated from vertebrae age bands. From December 2009 to November 2010, 423 R. acutus between 37 and 112 cm total length (L_T) were sampled along the Senegalese coast. Marginal increment ratio was used to check annual band deposition. Three growth models were adjusted to the length at age and compared using Akaike's information criterion. The Gompertz growth model with estimated size at birth appeared to be the best and resulted in growth parameters of L_∞ = 139·55 (L_T) and K = 0·17 year^?1 for females and L_∞ = 126·52 (L_T) and K = 0·18 year^?1 for males. The largest female and male examined were 8 and 9 years old, but the majority was between 1 and 3 years old. Ages at maturity estimated were 5·8 and 4·8 years for females and males, respectively. These results suggest that R. acutus is a slow‐growing species, which render the species particularly vulnerable to heavy fishery exploitation. The growth parameters estimated in this study are crucial for stock assessments and for demographic analyses to evaluate the sustainability of commercial harvests.     

Local trophic specialisation in a cosmopolitan spider (Araneae)

Trophic specialisation can be observed in species with long-term constant exploitation of a certain prey in all populations or in a population of a species with short-term exploitation of a certain prey. While in the former case the species would evolve stereotyped or specialised trophic adaptations, the trophic traits of the latter should be versatile or generalised. Here, we studied the predatory behavioural adaptations of a presumed myrmecophagous spider, Oecobius navus. We chose two distinct populations, one in Portugal and the other in Uruguay. We analysed the actual prey of both populations and found that the Portuguese population feeds mainly on dipterans, while the Uruguayan population feeds mainly on ants. Indeed, dipterans and springtails in Portugal, and ants in Uruguay were the most abundant potential prey. In laboratory trials O. navus spiders recognised and captured a wide variety of prey. The capture efficiency of the Portuguese population measured as components of the handling time was higher for flies than for ants, while that of the Uruguayan population was higher for ants. We found phenotypic plasticity in behavioural traits that lead to increased capture efficiency with respect to the locally abundant prey, but it remains to be determined whether the traits of the two populations are genetically fixed. We conclude that O. navus is a euryphagous generalist predator which shows local specialisation on the locally abundant prey.     

Condition of 0-group and adult pouting, Trisopterus luscus L., along the Portuguese coast: evidence of habitat quality and latitudinal trends

The present study assessed condition of pouting ( Trisopterus luscus Linnaeus, 1758) in nursery areas and other coastal areas along the Portuguese coast using different indices. Condition factor Fulton's K, RNA : DNA ratio and total protein content were determined for 0-group pouting collected in three shallow nursery grounds. Adult pouting were sampled in 10 sites along the coast and Fulton's K, hepatosomatic index (HSI), total protein content and water content were determined as indicators of condition. For 0-group individuals, only total protein content showed significant differences among the sites, whereas in adults all the indices evaluated differed significantly among the sites. However, due to high RNA : DNA ratios it was considered that all investigated nursery areas provided suitable conditions for survival and rapid growth of early stages of T. luscus . Adult pouting were also considered to be in good physical and nutritional condition along the Portuguese coast, although better growth conditions seem to be provided in the warmer waters of southern Portugal, evidencing a latitudinal trend.     

Strong genetic differentiation among east Atlantic populations of the sword razor shell (<Emphasis Type="Italic">Ensis siliqua</Emphasis>) assessed with mtDNA and RAPD markers

The sword razor shell Ensis siliqua (Linnaeus, 1758) is a bivalve with a high commercial value being appreciated in fresh and processed markets. However, the genetic studies carried out in populations of E. siliqua are scarce. In this work, the genetic variability and differentiation of the sword razor shell was assessed using PCR–RFLPs of a fragment of the 16S rRNA mitochondrial gene and random amplified polymorphic loci (RAPD) in nine localities from Ireland, Spain, and Portugal. In the 314 individuals examined for the mitochondrial fragment, 12 composite haplotypes were observed; meanwhile, a unique phenotype was observed for each of the 242 individuals analyzed with 61 RAPD loci. Two of the mitochondrial composite haplotypes accounted for the majority of individuals (89.81%) and showed a remarkably disjoint distribution between Irish and Iberian samples, with the exception of Aveiro which exhibited as the most frequent haplotype the same found in Ireland. The level of variability observed for each sample was generally correlated with both types of markers and the results obtained suggest the existence of a strong population differentiation between Irish and Iberian localities, except for the Portuguese sample from Aveiro which is surprisingly closer to Irish individuals, although it is probably highly differentiated.     

Plasticity responses of an invasive macrophyte species to inorganic carbon availability and to the interaction with a native species

The acorn barnacle Perforatus perforatus has a defined breeding temperature range and reproductive season that varies geographically. This study aims to investigate the influence of reproductive parameters of P. perforatus in species distribution ranges in the NE Atlantic. The hypothesis tested is that the breeding season of P. perforatus off NW Portugal begins earlier and is longer than at the northern distribution limit of this species, and that fecundity is higher in terms of number of broods per individual per breeding season. The span of the breeding season and fecundity indices were assessed based on the presence and maturation of ovigerous lamellae and correlated with temperature. Results showed that the breeding season in the NW Portuguese coast lasts over 10 months (February–November) and the number of broods was determined to be 9.2 ind/year. Temperature seems to be a primary factor determining the breeding season, but other factors, such as food availably, light and photoperiod, are also of great importance. However, the higher quantity of embryos produced in NW Portugal is not reflected in a higher abundance of settled adults in rocky shores. Contrarily, the species is particularly abundant in artificial substrata offshore.     

Reproduction,growth and mortality of the exploited sillaginid,Sillago ciliata Cuvier, 1829

The goal of this study was to examine the age and size composition, growth, reproductive biology and mortality of Sillago ciliata Cuvier, 1829 in one of the largest estuarine commercial fisheries in south‐eastern Australia. The study also aimed to present a qualitative comparison of latitudinal variations in some of these characteristics along the eastern Australian coastline. The sampled population contained fish aged up to 10 years with a maximum size of 39.2 cm fork length (L_F), and was dominated by 1–5 year olds. Sexual divergence in both the age and size structure of the population was recorded. Female S. ciliata grew slightly faster and attained a greater maximum size (L_∞ = 33.79 cm L_F, k = 0.50 year^?1 and t₀ = ?0.57 years) than males (L_∞ = 29.73 cm L_F, k = 0.49 year^?1 and t₀ = ?0.67 years). Females also matured at a significantly larger size (19.13 cm) and older age (1.63 years) than males (size: 17.07 cm, age: 1.10 years). Reproductive activity was highest between September and March. There were no differences between males and females in terms of mortality rate; the estimated total population, natural and fishing mortality rates were Z = 0.64, M = 0.42 and F = 0.22, respectively. Although these mortality rates suggest that S. ciliata in the Clarence River are relatively resilient to current rates of exploitation, regular monitoring of their commercial and recreational catch as well as their population structure is recommended in order to maintain sustainable fisheries. Potential latitudinal shifts in the spawning period, age structure and growth of S. ciliata along eastern Australia were also revealed.     

Shell microstructure of <Emphasis Type="Italic">Discinisca suborbicularis</Emphasis> sp. nov. (Brachiopoda,Lingulata) from the Upper Jurassic of Western Siberia

A new species of the phosphatic brachiopod Discinisca suborbicularis (family Discinidae) from the Upper Jurassic of Western Siberia (latitudinal Priob’e) is established. The shell microstructure under protegulum and brephic shell and the microstructure of adult shell (that corresponds to three developmental stages) are described in detail. The shell microstructure of new species considerably differs from Paleozoic discinids and is similar to Recent discinids. D. suborbicularis differs from recent discinids in the presence of protegulum and thicker organophosphatic primary layer.     

Gymnodinium catenatum Graham isolated from the Portuguese coast: Toxin content and genetic characterization

The bloom forming marine dinoflagellate Gymnodinium catenatum Graham has been linked to paralytic shellfish poisoning (PSP) outbreaks in humans. Along the Portuguese coast (NE Atlantic), G. catenatum shows a complex bloom pattern, raising questions about the origin and affinities of each bloom population. In this work, the variability within six cultured strains of G. catenatum isolated from Portuguese coastal waters (S coast, W coast and NW coast), between 1999 and 2011, was investigated. The strains were analyzed for toxin profiling and intra-specific genetic diversity. Regarding the toxin profile, differences recorded between strains could not be assigned to the time of isolation or geographical origin. The parameter that most influenced the toxin profile was the life-cycle stage that originated the culture: vegetative cell versus hypnozygote (resting cyst). At the genetic level, all strains showed similar sequences for the D1–D2 region of the large subunit (LSU) of the nuclear ribosomal DNA (rDNA) and shared complete identity with strains from Spain, Algeria, China and Australia. Conversely, we did not find a total identity match for the ITS-5.8S nuclear rDNA fragment. After sequence analysis, two guanine/adenine (R) single nucleotide polymorphisms (SNP 1 and 2) were detected for all strains, in the ITS1 region. This species has been reported to present very conservative LSU and ITS-5.8S rDNA regions, though with few SNP, including SNP1 of this study, already attributed to strains from certain locations. The SNP here described characterize G. catenatum populations from Portuguese waters and may represent valuable genetic markers for studies on the phylogeography of this species.     

Introgression in peripheral populations and colonization shape the genetic structure of the coastal shrub Armeria pungens

The coastal shrub Armeria pungens has a disjunct Atlantic-Mediterranean distribution. The historic range expansion underlying this distribution was investigated using the nuclear internal transcribed spacer region, three plastid regions (namely trnL-F, trnS-fM and matK) and morphometric data. A highly diverse ancestral lineage was identified in southwest Portugal. More recently, two areas have been colonized: (1) Corsica and Sardinia, where disjunct Mediterranean populations have been established as a result of the long-distance dispersal of Portuguese genotypes, and (2) the southern part of the Atlantic range, Gulf of Cadiz, where a distinct lineage showing no genetic differentiation among populations occurs. Genetic consequences of colonization seem to have been more severe in the Gulf of Cadiz than in Corsica-Sardinia. Although significant genetic divergence is associated with low plastid diversity in the Gulf of Cadiz, in Corsica-Sardinia, the loss of plastid haplotypes was not accompanied by divergence from disjunct Portuguese source populations. In addition, in its northernmost and southernmost populations, A. pungens exhibited evidence for ancient or ongoing introgression from sympatric congeners. Introgression might have created novel genotypes able to expand beyond the latitudinal margins of the species or, alternatively, these genotypes may be the result of surfing of alleles from other species in demographic equilibrium into peripheral populations of A. pungens. Our results highlight the evolutionary significance of genetic drift following the colonization of new areas and the key role of introgression in range expansion.     

Climate variability and Dinophysis acuta blooms in an upwelling system

Dinophysis acuta is a frequent seasonal lipophilic toxin producer in European Atlantic coastal waters associated with thermal stratification. In the Galician Rías, populations of D. acuta with their epicentre located off Aveiro (northern Portugal), typically co-occur with and follow those of Dinophysis acuminata during the upwelling transition (early autumn) as a result of longshore transport. During hotter than average summers, D. acuta blooms also occur in August in the Rías, when they replace D. acuminata. Here we examined a 30-year (1985–2014) time series of D. acuta from samples collected by the same method in the Galician Rías. Our main objective was to identify patterns of distribution and their relation with climate variability, and to explain the exceptional summer blooms of D. acuta in 1989–1990. A dome-shaped relationship was found between summer upwelling intensity and D. acuta blooms; cell maxima were associated with conditions where the balance between upwelling intensity and heating, leading to deepened thermoclines, combined with tidal phase (3 days after neap tides) created windows of opportunity for this species. The application of a generalized additive model based on biological (D. acuta inoculum) and environmental predictors (Cumulative June–August upwelling CUI_JJA, average June–August SST_JJA and tidal range) explained more than 70% of the deviance for the exceptional summer blooms of D. acuta, through a combination of moderate (35,000–50,000 m³ s⁻¹ km⁻¹) summer upwelling (CUI_JJA), thermal stratification (SST_JJA > 17 °C) and moderate tidal range (∼2.5 m), provided D. acuta cells (inoculum) were present in July. There was no evidence of increasing trends in D. acuta bloom frequency/intensity nor a clear relationship with NAO or other long-term climatic cycles. Instead, the exceptional summer blooms of 1989–1990 appeared linked to extreme hydroclimatic anomalies (high positive anomalies in SST and NAO index), which affected most of the European Atlantic coast.