Quantifying the roles of competing static gears: comparative selectivity of longlines and monofilament gill nets in a multi-species fishery of the Algarve (southern Portugal)

Fishing trials with monofilament gill nets and longlines using small hooks were carried out in Algarve waters (southern Portugal) over a one-year period. Four hook sizes of "Mustad" brand, round bent, flatted sea hooks (Quality 2316 DT, numbers 15, 13, 12 and 11) and four mesh sizes of 25, 30, 35 and 40 mm (bar length) monofilament gill nets were used. Commercially valuable sea breams dominated the longline catches while small pelagics were relatively more important in the gill nets. Significant differences in the catch size frequency distributions of the two gears were found for all the most important species caught by both gears (Boops boops, Diplodus bellottii, Diplodus vulgaris, Pagellus acarne, Pagellus erythrinus, Spondyiosoma cantharus, Scomber japonicus and Scorpaena notata), with longlines catching larger fish and a wider size range than nets. Whereas longline catch size frequency distributions for most species for the different hook sizes were generally highly overlapped, suggesting little or no differences in size selectivity, gill net catch size frequency distributions clearly showed size selection. A variety of models were fitted to the gill net and hook data using the SELECT method, while the parameters of the logistic model were estimated by maximum likelihood for the longline data. The bi-normal model gave the best fits for most of the species caught with gill nets, while the logistic model adequately described hook selectivity. The results of this study show that the two static gears compete for many of the same species and have different impacts in terms of catch composition and size selectivity. This information will I;e useful for the improved management of these small-scale fisheries in which many different gears compete for scarce resources.

Semi-pelagic longline selectivity for two demersal species from the Azores: the black spot sea bream (Pagellus bogaraveo) and the bluemouth rockfish (Helicolenus dactylopterus dactylopterus)

The selectivity of four hook sizes (STELL brand(1), Quality 2335, numbers 12, 9, 6 and 4) used in a semi-pelagic longline fishery was studied in the Azores. Two species were caught in sufficient numbers for modelling of selectivity: the black spot sea bream (Pagellus bogaraveo) and the bluemouth rockfish (Helicolenus dactylopterus dactylopterus). A maximum likelihood method was used to fit a versatile model which can be used to describe a wide range of selectivity curves; from bell-shaped to asymptotic. Significant differences in size selectivity between hooks were found for both species. In the case of Pagellus bogaraveo, the smallest hook (number 12) had the lowest catch rates and all hooks were characterised by logistic-type selectivity curves, with sizes at 50% selectivity of: 27.9, 30.4, and 32.8 cm for hooks numbers 12, 9 and 6, respectively. The number 9 hook was the most efficient for Helicolenus d. dactylopterus, with selectivity curves varying from strongly skewed to the right for the number 12 hook to logistic-type for the numbers 6 and 4 hooks. Sizes at 50% selectivity for this species were 16.8, 18.7, 20.7, and 22.0 cm. respectively. (C) 1999 Elsevier Science B.V. All rights reserved.

Species and size selectivity in a Portuguese multispecies artisanal long-line fishery

The species and size selectivity of long-lines using small hooks were studied off the south coast of Portugal using ''Mustad'' brand round bent, flatted sea hooks (Quality 2316 DT) numbers 15, 13, and 11 baited with razor shell clam (Ei-isis siliqua). Hook numbers 13 and 11 are 49 and 109% larger respectively than number 15 hooks in terms of overall size (maximum width x maximum length). A total of 39 900 hooks were fished in 45 sets and 35 species of fish and cephalopods were caught. As a group, 13 species of sea breams (Sparidae) dominated the catch by numbers (58%) and weight (73%). Six species of sea breams, along with the greater weever fish (Trachinus draco) accounted for 81% of the total catch by weight, with the common or white sea bream (Diplodus sargus) bring the most important (29%). Catch size distributions by hook size were, in general, highly overlapped for all species and hook size had little apparent effect on minimum size at capture. All hooks caught a wide range of sizes per species, but the catch rate (number of fish per 100 hooks) was significantly lower for the largest hook. Except for the black sea bream (Spondyliosoma cantharus), capture of illegally sized or immature fish was minimal. Small increases in average size with hook size were evident for four species: Diplodus sargus, D. vulgaris, Lithognathus mormyrus and Serranus cabrilla. No differences in size selectivity were detected for Boops boops, D. annularis, Spondyliosoma cantharus and Trachinus draco. A skew-normal model adequately described differences in size selectivity in five of six species. (C) 1996 International Council for the Exploration of the Sea

A conservation trade-off? Interspecific differences in seahorse responses to experimental changes in fishing effort

1. A 2-year experimental seining programme and underwater visual censuses were undertaken to quantify the direct effects of active demersal fishing on the population structure and relative abundance of two sympatric seahorse species of conservation concern: the European long-snouted seahorse, Hippocampus guttulatus Cuvier 1829 and the short-snouted seahorse, Hippocampus hippocampus L. The influence of habitat preference on population-level responses to changes in habitat structure following a reduction in fishing effort was also investigated. 2. It was predicted that the benthic habitat would be more structurally complex after fishing ceased and that seahorse densities would increase in response to reduced fishing mortality. Furthermore, it was predicted that the magnitude of the increase in density would be greater for H. guttulatus than for H. hippocampus, because the former species prefers complex vegetated habitats while the latter species uses sparsely vegetated habitats. 3. As predicted, the amount of habitat cover increased significantly when seining ceased, primarily through increases in the abundance of drifting macroalgae and unattached invertebrates. Despite similarities in life histories, the two seahorse species responded differently in terms of magnitude and direction to reduced fishing effort: the abundance of H. guttulatus increased significantly while H. hippocampus decreased in abundance. 4. Results suggest that active demersal fishing may influence the magnitude and direction of the responses of benthic marine fishes to exploitation through its impacts on habitat structure. An increase in habitat cover appeared to favour higher densities of H. guttulatus when seining effort was reduced. By contrast, repeated seining, which maintained less complex habitats, appeared to favour greater abundances of H. hippocampus. 5. Given differences in habitat preference among benthic marine fishes subject to incidental capture in fisheries, simultaneous attempts to manage populations of sympatric species may require complementary strategies that support the persistence of diverse habitat types. Copyright (c) 2006 John Wiley & Sons, Ltd.

Catches of the sport fishing competitions along the Algarve coast (Portugal): species, sizes, catch rates, and trends

Background. Stocks of many marine fishes are in decline and a number of studies suggest that for some species the impact of recreational angling may be important. To date, only recreational (leisure) fishing surveys have been conducted in Portugal, with no studies on beach angling competitions, dynamically increasing in number over the past 10 to 20 years. In view of the above, we decided to evaluate the impact of such events on the Algarve coast (southern Portugal) in terms of the abundance, diversity, and respective weight of fish species caught and outline some conservation measures and recommendations for the management of the targeted species. Materials and methods. Participants of 22 angling competitions taking place between February and June 2007 were surveyed. In each competition a random sample of anglers was interviewed, and the specimens caught by each participant were identified, weighed, and measured. Results. Thirteen taxa belonging to eight families were identified, and the most common were: garfish, Belone belone (Linnaeus, 1761); mullets, Mugilidae (not identified); and mackerels, Scomber spp. A total of 563 specimens were sampled, totalling 75.4 kg of weight, with the average catch per angler weighing 0.5 +/- 0.05 SE (n = 153) kg. Differences were also observed between the length at first maturity (L(50)) of the specimens caught and their respective Minimum Landing Size (MLS) and Allowed Minimum Size (AMS), most particularly in the case of the European seabass, Dicentrarchus labrax (L.), with almost all individuals caught measuring below the species-specific L50. Analysis of time series of competition results (1996-2009) showed no evidence of a decrease in catches or in mean weight. Conclusion. Based on the results we propose that the AMS for beach angling competitions should be increased to the MLS in order to prevent the capture of juvenile fishes, especially the sea bass. Future studies should address the size selectivity of the hooks used in beach competitions, with a view to the implementation of a minimum hook size for competitions.

Species delimitation in sharpnose sharks (genus Rhizoprionodon) in the western Atlantic Ocean using mitochondrial DNA

Despite Springer’s (1964) revision of the sharpnose sharks (genus Rhizoprionodon), the taxonomic definition and ranges of Rhizoprionodon in the western Atlantic Ocean remains problematic. In particular, the distinction between Rhizoprionodon terraenovae and R. porosus, and the occurrence of R. terraenovae in South American waters are unresolved issues involving common and ecologically important species in need of fishery management in Caribbean and southwest Atlantic waters. In recent years, molecular markers have been used as efficient tools for the detection of cryptic species and to address controversial taxonomic issues. In this study 415 samples of the genus Rhizoprionodon captured in the western Atlantic Ocean from Florida to southern Brazil were examined for sequences of the COI gene and the D-loop and evaluated for nucleotide differences. The results on nucleotide composition, AMOVA tests, and relationship distances using Bayesian-likelihood method and haplotypes network, corroborates Springer’s (1964) morphometric and meristic finding and provide strong evidence that supports consideration of R. terraenovae and R. porosus as distinct species.

First report of Ciguatoxins in two starfish species: Ophidiaster ophidianus and Marthasterias glacialis

Ciguatera fish poisoning (CFP) is a syndrome caused by the ingestion of fish contaminated with Ciguatoxins (CTXs). These phycotoxins are produced mainly by dinoflagellates that belong to the genus Gambierdiscus that are transformed in more toxic forms in predatory fish guts, and are more present in the Indo-Pacific and Caribbean areas. It is estimated that CFP causes per year more than 10,000 intoxications worldwide. With the rise of water temperature and anthropogenic intervention, it is important to study the prevalence of CFP in more temperate waters. Through inter- and subtidal sampling, 22 species of organisms were collected, in Madeira and Azores archipelagos and in the northwestern Moroccan coast, during September of 2012 and June and July of 2013. A total of 94 samples of 22 different species of bivalves, gastropods, echinoderms and crustaceans where analyzed by Ultra Performance Liquid Chromatography-Mass Spectometry-Ion Trap-Time of Flight (UPLC-MS-IT-TOF) and Ultra Performance Chromatography- Mass Spectrometry (UPLC-MS). Our main aim was to detect new vectors and ascertain if there were some geographical differences. We detected for the first time putative CTXs in echinoderms, in two starfish species—M. glacialis and O. ophidianus. We detected differences regarding uptake values by organisms and geographical location. Toxin amounts were significant, showing the importance and the need for continuity of these studies to gain more knowledge about the prevalence of these toxins, in order to better access human health risk. In addition, we suggest monitoring of these toxins should be extended to other vectors, starfish being a good alternative for protecting and accessing human health risk.

Effects of flow regulation in the life-cycles of a mediterranean cyprinid species, the Iberian chub (Squalius carolitertii Doadrio, 1987)

Streamflow is considered a driver of inter and intra‐specific life‐history differences among freshwater fish. Therefore, dams and related flow regulation, can have deleterious impacts on their life‐cycles. The main objective of this study is to assess the effects of flow regulation on the growth and reproduction of a non‐migratory fish species. During one year, samples were collected from two populations of Iberian chub, inhabiting rivers with non‐regulated and regulated flow regimes. Flow regulation for water derivation promoted changes in chub’s condition, duration of gonad maturation and spawning, fecundity and oocyte size. However, this non‐migratory species was less responsive to streamflow regulation than a migratory species analysed. Findings from this study are important to understand changes imposed by regulated rivers on fish and can be used as guidelines for flow requirements implementations; RESUMO: O caudal é um dos fatores responsáveis pelo funcionamento dos ciclos de vida das espécies piscícolas dulciaquícolas. As barragens, e a regularização de caudal associada, podem ter impactes nos ciclos de vida destas espécies. O objetivo deste estudo prende‐se com a avaliação dos efeitos da regularização de caudal no crescimento e reprodução de uma espécie piscícola não‐migradora. A análise de amostras recolhidas em populações de escalo do Norte provenientes de dois rios de caudal regularizado e não regularizado, identificaram impactes significativos a nível da condição corporal, da maturação das gónadas e desova, da fecundidade e da dimensão dos oócitos. Esta espécie não‐migradora parece ser menos responsiva à artificialização do caudal que uma espécie migradora previamente analisada. Estes resultados permitem compreender as alterações impostas pela regularização do caudal e podem ser usados em programas de reabilitação fluvial.

Differences between root traits of early- and late-successional trees influence below-ground competition and seedling establishment.

The competitive influence of the root system of the exotic grass Urochloa brizantha and the widespread forb Leonotis nepetifolia on the emergence, survival and early growth of the seedlings of eight tropical heliophilous herbaceous species, six early-successional woody species and five late-successional woody species from Brazil, grown in 3500-cm3 pots and in greenhouse without light restriction were assessed. The density of fine-root systems produced by the forb and the grass in pots were 6.8 cm cm-3 soil and 48.1 cm cm-3 soil, respectively. Seedlings survival of the heliophilous herbaceous, early- and late-successional woody species were 86%, 70% and 100% in presence of the forb root system and 12%, 14% and 100% in competition with grass root system, respectively. The competitive pressure applied by the grass root system on seedling growth of the heliophilous herbaceous, early- and late-successional woody species were 2.4, 1.9 and 1.4 times greater than the forb root system. Total root length of the heliophilous herbaceous, early- and late-successional woody species grown without competitors were 13, 33 and 5 times greater than in competition with forb, and were 66, 54 and 6 times greater than in competition with grass root system, respectively. The averages of fine-root diameter of plants grown without competitors were 209 microm for the heliophilous herbaceous, 281 microm for early-successional trees and 382 microm for late-successional trees. The root system of the forb did not avoid seedling establishment of most plant species, but the grass root system hampered more the establishment of heliophilous herbaceous and early-successional woody species than the seedling establishment of late-successional woody species. The different density of root systems produced in soil by the forb and the grass, and the distinct root traits (e.g. root diameter and root tissue density) of the early- and late-successional plant species can explain the differences in the establishment of seedlings of plant species belonging to different groups of tropical succession when exposed to below-ground competition.

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of the Anastrepha fraterculus complex (Diptera: Tephritidae).

An integrative multidisciplinary approach was used to delimit boundaries among cryptic species within the Anastrepha fraterculus complex in Brazil. Sexual compatibility, courtship and sexual acoustic behaviour, female morphometric variability, variation for the mitochondrial gene COI, and the presence of Wolbachia were compared among A. fraterculus populations from the Southern (Vacaria, Pelotas, Bento Gonçalves, S~ao Joaquim) and Southeastern (Piracicaba) regions of Brazil. Our results suggest full mating compatibility among A. fraterculus populations from the Southern region and partial pre-zygotic reproductive isolation of these populations when compared with the population from the Southeastern region. A. fraterculus populations from both regions differed in the frequency of courtship displays and aspects of the calling phase and mounting acoustic signal. Morphometric analysis showed differences between Southern region and Southeastern region samples. All populations analyzed were infected with Wolbachia. The trees generated from the COI sequencing data are broadly congruent with the behavioural and morphometric data with the exception of one Southern population. The likely mechanisms by which A. fraterculus populations might have diverged are discussed in detail based on behavioural, morphometric, molecular genetics, and biogeographical studies

Fusarium head blight: characterization of secondary Fusarium species, evaluation of their pathogenetic role and ability to produce mycotoxins

Fusarium head blight (FHB) is a worldwide cereal disease caused by a complex of Fusarium species resulting in high yield losses, reduction in quality and mycotoxin contamination of grain. A shift in Fusarium head blight community has been observed worldwide. The present work aimed to analyze the evolution of Italian FHB community focusing the attention on species considered “secondary” in the past years such as members of Fusarium tricinctum species complex (FTSC) and F. proliferatum. The first goal of the study was to analyze the fungal community associated with Italian durum wheat in two different years. F. poae, F. avenaceum and F. proliferatum were the main species detected on Italian durum kernels. A variable mycotoxins contamination was observed in the analyzed samples. Considering, the increased incidence of F. avenaceum and other members of FTSC in Italian FHB, the second aim was to investigate genetic diversity among the FTSC and estimate the mycotoxin risk related to these species. Phylogenetic analyses revealed that F. avenaceum (FTSC 4) was the most common species in Italy, followed by an unnamed Fusarium sp., F. tricinctum and F. acuminatum. In addition to these four phylospecies, five other F. tricinctum clade species were sampled. These included strains of four newly discovered species (Fusarium spp. FTSC 11, 13, 14, 15) and F. iranicum (FTSC 6). Most isolates tested for mycotoxin production on rice cultures were able to produce quantitative levels of enniatins and moniliformin. In addition, a preliminary study was conducted to evaluate the ability of a selected F. proliferatum isolate to produce fumonisins on wheat in open field and under natural climatic conditions. The three analogues (FB1, FB2 and FB3) were quantified by HPLC-FLD analysis on kernels, chaff and rachis. Fumonisins were detected in all the three investigated fractions without significant differences.

Non conventional species as monitor of environmental pollution

This thesis collects several ecotoxicological studies focused on the quali- quantitative analysis of several classes of chemical compounds. Our studies have been conducted on different aquatic species occupying different food chain trophic levels and characterized by differences in biology, ethology, and nutrition, but all considered excellent bioindicators. This choice allowed us to have a broad overview of the contamination of aquatic environments. Detrimental effects of several chemical compounds on the species investigated have been discussed, considering the economic and public health implications linked to the pollution of the environment and the exposure to old and emerging xenobiotics. Our studies underline the importance of a multidisciplinary and integrated approach that includes the application of the one health concept to ensure the protection of public health and respect for natural environments. Studies collected in this thesis also aim to overcome some critical limitations of the branch of ecotoxicology, such as the lack of standardization in laboratory methods. Our data also underline the importance of expanding research to a greater number of various biological matrices than those indicated by the literature as target tissues for specific pollutants. This condition enables more detailed information on the kinetics of xenobiotics in animal organisms. Our studies also allow us to expand the knowledge related to the mechanisms of synergy and antagonism of mixtures of pollutants that can simultaneously accumulate in wildlife.

Investigation of plant genetic-microbiome interactions in different plant species

The rhizosphere, i.e. the soil surrounding the plant roots, and endosphere, i.e. the microbial communities within the plant organs harbors microbes known to influence root and plant physiological processes. An important question is to what extent plant species, genotypes and environmental conditions affect bacterial and fungal communities. The objectives of the first research study were to unravel and compare the rhizospheric microbiota of grape in two independent vineyards using 16S and ITS amplicon sequencing, evaluate location and varietal effects, and test the correlation between bioavailable copper levels and other soil parameters with microbiota composition and diversity. Our results showed that the microbial alpha diversity based on Shannon index differed significantly between vineyards while it did not differ between two grape cultivars. In the second study, we were focusing on different wheat species and genotypes such as Bread Wheat, Wild Emmer Wheat, Domesticated Emmer Wheat, Durum Wheat Landraces, Durum Wheat cultivars, T. monococcum and triticale in two fields located in Bologna and Foggia. The objectives of this research experiment were to elucidate and compare the rhizospheric and endophytic microbiota of 30 diverse wheat genotypes in two different fields using 16S amplicon sequencing. Our results showed that the microbial alpha diversity based on Shannon index differed significantly between fields of Bologna and Foggia, in which Bologna had a higher diversity in respect to Foggia for both rhizospheric and endophytic communities. Using Shannon index there was significant differences, for instance, between Durum Emmer Wheat and Wild Emmer Wheat in Bologna, and between Bread Wheat and Durum Wheat Landraces in Foggia. Our results contribute to understand the role of wheat species and genotype and the filed management on the root-microbe-soil interactions in the perspective of understanding their impact on crop systems sustainability.

Spatial-temporal variability of the benthic communities in Ravenna harbour using Autonomous Reef Monitoring Structures (ARMS) with focus on Non-Indigenous Species (NIS)

A Non-Indigenous Species (NIS) is defined as an organism, introduced outside its natural past or present range of distribution by humans, that successfully survives, reproduces, and establish in the new environment. Harbors and tourist marinas are considered NIS hotspots, as they are departure and arrival points for numerous vessels and because of the presence of free artificial substrates, which facilitate colonization by NIS. To early detect the arrival of new NIS, monitoring benthic communities in ports is essential. Autonomous Reef Monitoring Structures (ARMS) are standardized passive collectors that are used to assess marine benthic communities. Here we use an integrative approach based on multiple 3-month ARMS deployment (from April 2021 to October 2022) to characterize the benthic communities (with a focus on NIS) of two sites: a commercial port (Harbor) and a touristic Marina (Marina) of Ravenna. The colonizing sessile communities were assessed using percentage coverage of the taxa trough image analyses and vagile fauna (> 2 mm) was identified morphologically using a stereomicroscope and light microscope. Overall, 97 taxa were identified and 19 of them were NIS. All NIS were already observed in port environments in the Mediterranean Sea, but for the first time the presence of the polychaete Schistomeringos cf. japonica (Annenkova, 1937) was observed; however molecular analysis is needed to confirm its identity. Harbor and Marina host significantly different benthic communities, with significantly different abundance depending on the sampling period. While the differences between sites are related to their different environmental characteristic and their anthropogenic pressures, differences among times seems related to the different life cycle of the main abundant species. This thesis evidenced that ARMS, together with integrative taxonomic approaches, represent useful tools to early detect NIS and could be used for a long-term monitoring of their presence.

Cytogenetic And Morphologic Approaches Of Hybrids From Experimental Crosses Between Triatoma Lenti Sherlock & Serafim, 1967 And T. Sherlocki Papa Et Al., 2002 (hemiptera: Reduviidae).

The reproductive capacity between Triatoma lenti and Triatoma sherlocki was observed in order to verify the fertility and viability of the offspring. Cytogenetic, morphological and morphometric approaches were used to analyze the differences that were inherited. Experimental crosses were performed in both directions. The fertility rate of the eggs in crosses involving T. sherlocki females was 65% and 90% in F1 and F2 offspring, respectively. In reciprocal crosses, it was 7% and 25% in F1 and F2 offspring, respectively. The cytogenetic analyses of the male meiotic process of the hybrids were performed using lacto-acetic orcein, C-banding and Feulgen techniques. The male F1 offspring presented normal chromosome behavior, a finding that was similar to those reported in parental species. However, cytogenetic analysis of F2 offspring showed errors in chromosome pairing. This post-zygotic isolation, which prevents hybrids in nature, may represent the collapse of the hybrid. This phenomenon is due to a genetic dysregulation that occurs in the chromosomes of F1. The results were similar in the hybrids from both crosses. Morphological features, such as color and size of connexive and the presence of red-orange rings on the femora, were similar to T. sherlocki, while wins size was similar to T. lenti in F1 offspring. The eggshells showed characteristics that were similar to species of origin, whereas the median process of the pygophore resulted in intermediate characteristics in the F1 and a segregating pattern in F2 offspring. Geometric morphometric techniques used on the wings showed that both F1 and F2 offspring were similar to T. lenti. These studies on the reproductive capacity between T. lenti and T. sherlocki confirm that both species are evolutionarily closed; hence, they are included in the brasiliensis subcomplex. The extremely reduced fertility observed in the F2 hybrids confirmed the specific status of the species that were analyzed.