Footprints in the sand: a persistent spatial impression of fishing in a mobile groundfish assemblage

Fishing is well known to curtail the size distribution of fish populations. This paper reports the discovery of small-scale spatial patterns in length appearing in several exploited species of Celtic Sea demersal 'groundfish'. These patterns match well with spatial distributions of fishing activity, estimated from vessel monitoring records taken over a period of 6 years, suggesting that this 'mobile' fish community retains a persistent impression of local-scale fishing pressure. An individual random-walk model of fish movement best matched these exploitation 'footprints' with individual movement rates set to <35 km per year. We propose that Celtic Sea groundfish may have surprisingly low movement rates for much of the year, such that fishing impact is spatially heterogeneous and related to local fishing intensity.

Estimating biomass, fishing mortality, and "total allowable discards" for surveyed non-target fish

Demersal fisheries targeting a few high-value species often catch and discard other "non-target" species. It is difficult to quantify the impact of this incidental mortality when population biomass of a non-target species is unknown. We calculate biomass for 14 demersal fish species in ICES Area VIIg (Celtic Sea) by applying species-and length-based catchability corrections to catch records from the Irish Groundfish Survey (IGFS). We then combine these biomass estimates with records of commercial discards (and landings for marketable non-target species) to calculate annual harvesting rates (HR) for each study species. Uncertainty is incorporated into estimates of both biomass andHR. Our survey-based HR estimates for cod and whiting compared well with HR-converted fishing mortality (F) estimates from analytical assessments for these two stocks. Of the non-target species tested, red gurnard (Chelidonichthys cuculus) recorded some annual HRs greater than those for cod or whiting; challenging "Pope's postulate" that F on non-target stocks in an assemblage will not exceed that on target stocks. We relate HR for each species to two corresponding maximum sustainable yield (MSY) reference levels; six non-target species (including three ray species) show annual HRs >= HRMSY. This result suggests that it may not be possible to conserve vulnerable non-target species when F is coupled to that of target species. Based on biomass, HR, and HRMSY, we estimate "total allowable catch" for each non-target species.

Fish product mislabelling: failings of traceability in the production chain and implications for illegal, unreported and unregulated (IUU) fishing

Increasing consumer demand for seafood, combined with concern over the health of our oceans, has led to many initiatives aimed at tackling destructive fishing practices and promoting the sustainability of fisheries. An important global threat to sustainable fisheries is Illegal, Unreported and Unregulated (IUU) fishing, and there is now an increased emphasis on the use of trade measures to prevent IUU-sourced fish and fish products from entering the international market. Initiatives encompass new legislation in the European Union requiring the inclusion of species names on catch labels throughout the distribution chain. Such certification measures do not, however, guarantee accuracy of species designation. Using two DNA-based methods to compare species descriptions with molecular ID, we examined 386 samples of white fish, or products labelled as primarily containing white fish, from major UK supermarket chains. Species specific real-time PCR probes were used for cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) to provide a highly sensitive and species-specific test for the major species of white fish sold in the UK. Additionally, fish-specific primers were used to sequence the forensically validated barcoding gene, mitochondrial cytochrome oxidase I (COI). Overall levels of congruence between product label and genetic species identification were high, with 94.34% of samples correctly labelled, though a significant proportion in terms of potential volume, were mislabelled. Substitution was usually for a cheaper alternative and, in one case, extended to a tropical species. To our knowledge, this is the first published study encompassing a large-scale assessment of UK retailers, and if representative, indicates a potentially significant incidence of incorrect product designation.

Gene-associated markers provide tools for tackling illegal fishing and false eco-certification

Illegal, Unreported and Unregulated fishing has had a major role in the overexploitation of global fish populations. In response, international regulations have been imposed and many fisheries have been 'eco-certified' by consumer organizations, but methods for independent control of catch certificates and eco-labels are urgently needed. Here we show that, by using gene-associated single nucleotide polymorphisms, individual marine fish can be assigned back to population of origin with unprecedented high levels of precision. By applying high differentiation single nucleotide polymorphism assays, in four commercial marine fish, on a pan-European scale, we find 93-100% of individuals could be correctly assigned to origin in policy-driven case studies. We show how case-targeted single nucleotide polymorphism assays can be created and forensically validated, using a centrally maintained and publicly available database. Our results demonstrate how application of gene-associated markers will likely revolutionize origin assignment and become highly valuable tools for fighting illegal fishing and mislabelling worldwide.

Biomass fly ash incorporation in cement based materials

In recent years, pressures on global environment and energy security have led to an increasing demand on renewable energy sources, and diversification of Europe’s energy supply. Among these resources the biomass could exert an important role, since it is considered a renewable and CO2 neutral energy resource once the consumption rate is lower than the growth rate, and can potentially provide energy for heat, power and transports from the same installation. Currently, most of the biomass ash produced in industrial plants is either disposed of in landfill or recycled on agricultural fields or forest, and most times this goes on without any form of control. However, considering that the disposal cost of biomass ashes are raising, and that biomass ash volumes are increasing worldwide, a sustainable ash management has to be established. The main objective of the present study is the effect of biomass fly ashes in cement mortars and concretes in order to be used as a supplementary cementitious material. The wastes analyzed in the study were collected from the fluidized bed boilers and grate boilers available in the thermal power plants and paper pulp plants situated in Portugal. The physical as well as chemical characterisations of the biomass fly ashes were investigated. The cement was replaced by the biomass fly ashes in 10, 20 and 30% (weight %) in order to investigate the fresh properties as well as the hardened properties of biomass fly ash incorporated cement mortar and concrete formulations. Expansion reactions such as alkali silica reaction (ASR), sulphate attack (external and internal) were conducted in order to check the durability of the biomass fly ash incorporated cement mortars and concretes. Alternative applications such as incorporation in lime mortars and alkali activation of the biomass fly ashes were also attempted. The biomass fly ash particles were irregular in shape and fine in nature. The chemical characterization revealed that the biomass fly ashes were similar to a class C fly ash. The mortar results showed a good scope for biomass fly ashes as supplementary cementitious materials in lower dosages (<20%). The poor workability, concerns about the organic content, alkalis, chlorides and sulphates stand as the reasons for preventing the use of biomass fly ash in high content in the cement mortars. The results obtained from the durability tests have shown a clear reduction in expansion for the biomass fly ash mortars/concretes and the binder blend made with biomass fly ash (20%) and metakaolin (10%) inhibited the ASR reaction effectively. The biomass fly ash incorporation in lime mortars did not improve the mortar properties significantly though the carbonation was enhanced in the 15-20% incorporation. The biomass fly ash metakaolin blend worked well in the alkali activated complex binder application also. Portland cement free binders (with 30-40 MPa compressive strength) were obtained on the alkali activation of biomass fly ashes (60-80%) blended with metakaolin (20-40%).

Follow up on the local implementation of an MPA in the small fishing village of San Felipe, Yucatan

Dissertação mest., Biologia Marinha, Universidade do Algarve, 2007

Macrofauna spatial differences within clam dredge-tracks and their implications for short-term fishing effect studies

In situ observations of clam dredging showed that the effects of the dredge on the benthic macrofauna may not be constant during a tow. A sand buffer forms in front of the gear approximately 10m after the beginning of a tow, and this pushes the sediment partially aside.In this study, we analyse differences in abundance, the number of taxa present, diversity, and evenness within sections of dredge-tracks in a disturbed, fished area and a non-fished area along the southern coast of Portugal. These areas were sampled by divers before and after dredge-fishing activity. At each site, three dredge-tracks were produced. These tracks were divided in three longitudinal sections 1start, middle and end) and two transverse sections 1track and edge). Six quadrats were used to sample macrofauna in each section of every track and edge. Our results show differences exist in macro- faunal distribution and abundance across sections of a dredge-track. These differences should be considered in any assessment of the short-term ecological impact of dredges on benthic macrofauna

Recreational shore fishing in southern Portugal: biological and socio-economic aspects and perspectives for management

Although overfishing is a concern for many fish stocks, it was for a long time only associated with commercial fishing exploitation, with less or no attention being given to the recreational fisheries. Recent research has shown however that the impact of recreational fishing on particular species can be considerable, and that the recreational harvest needs to be taken into account if fisheries are to be accurately assessed and effectively managed. In Portugal, the first recreational fishing regulations were only recently implemented. However, mirroring other European countries, regulations lacked scientific support, and specific knowledge of the activity was limited to a few studies with limited coverage. This thesis aimed to characterize the biological and socioeconomic aspects of the recreational shore angling activity in southern Portugal, to investigate whether the regulations in place were adequate and effective, and to provide recommendations for improved management and conservation of the inshore fisheries resources. A combined aerial-roving survey was conducted to gather data on fishing effort, catch, fishing trips and socioeconomic aspects (including anglers’ perceptions of regulations) of the recreational angling activity. The analysis of anglers’ catches suggested that compliance with daily bag limits was high, with less than 0.5% of creels exceeding the 10 kg angler-1 day-1 bag limit. Overall, 11.5% of the retained fishes were undersized, but non-compliance with minimum size limits was found to be high for some species (e.g. seabass, 73% undersized). In terms of the impact of recreational shore angling, the total estimated catches corresponded to less than 1% of the commercial landings for the same period (shared species). However, shore angling catches for white sea bream (Diplodus sargus) were found to be considerable, corresponding to 65% of the commercial landings (39.4% of total catch). In terms of anglers’ perceptions about the recreational fishing regulations in Portugal, the present study has shown that the majority of anglers accepted the existence of some kind of SRF regulations, but in general there was a partial or total disagreement with the recreational fishing restrictions recently put in place. Most anglers perceived themselves as not being involved in the decision-making process and claimed that some restrictions lacked a meaningful rationale (e.g. prohibition of fishing from piers/jetties). Fishers’ awareness with regard to specific aspects of the restrictions (such as the rationale for minimum size limits) was found to be very limited. During the same period, catches from sport fishing competitions were examined to test for differences with the recreational activity in terms of catches, and evaluate long term trends in catch and mean size of fish. Catches of the sport fishing competitions were found to be different from those observed for recreational fishing, being dominated by different species (e.g. garfish, mullets), and suggesting different fishing strategies of the the two types of anglers. High percentages of undersized fish were observed to be captured (and retained) during the competitions (in particular seabass, with 100% undersized), probably as a result of a single allowable minimum size (AMS) of 15 cm for all species in use in competitions. Lastly, catch and release fishing experiments were carried out to assess post-release mortality of three recreationally important species: two banded sea bream Diplodus vulgaris; black sea bream Spondyliosoma cantharus; and gilthead sea bream Sparus aurata. Post-release mortalities were found to be low (0-12%). The main predictor of mortality for Sparus aurata was anatomical hooking location, with 63% of the fishes that died being deeply hooked. The results support the release of fish, either from mandatory (e.g. minimum landing sizes) or voluntary practices. In summary, this thesis has demonstrated that the impact of recreational fishing for particular species is significant and needs to be taken into account for more effective management and stock assessment purposes. It has also highlighted several management issues that should be addressed in order to promote more adequate regulations in the future and prevent noncompliance issues. A periodic monitoring of the recreational fishing activity including all fishing modes (i.e. spear fishing, boat, and shore angling) would also be beneficial to ensure a timely knowledge on the global recreational fishing activity and support future management actions.

Habitat use and diel vertical migration of bigeye thresher shark: overlap with pelagic longline fishing gear

Pelagic longliners targeting swordfish and tunas in oceanic waters regularly capture sharks as bycatch, including currently protected species as the bigeye thresher, Alopias superciliosus. Fifteen bigeye threshers were tagged with pop-up satellite archival tags (PSATs) in 2012-2014 in the tropical northeast Atlantic, with successful transmissions received from 12 tags for a total of 907 tracking days. Marked diel vertical movements were recorded on all specimens, with most of the daytime spent in deeper colder water (mean depth = 353 m, SD = 73; mean temperature = 10.7 °C, SD = 1.8) and nighttime spent in warmer water closer to the surface (mean depth = 72 m, SD = 54; mean temperature = 21.9 °C, SD = 3.7). The operating depth of the pelagic longline gear was measured with Minilog Temperature and Depth Recorders (TDRs), and the overlap with habitat utilization was calculated. Overlap is taking place mainly during the night and is higher for juveniles. The results presented herein can be used as inputs for Ecological Risk Assessments for bigeye threshers captured in oceanic tuna fisheries, and serve as a basis for efficient management and conservation of this vulnerable shark species.

Summary of Charter Fishing Laws 2015-2016

Each year the South Carolina Department of Natural Resources publishes a summary of the laws and regulations of commercial fishing in the state. This publication provides the license requirements, definitions, restrictions, and laws and regulations for the use of charter fishing laws.

Anthropogenic impacts in the deep sea of the Azores : fishing and litter

Tese de Doutoramento em Ciências do Mar, especialidade em Ecologia Marinha.

Fly by data link: feasibility of a relative navigation solution for aviation relying on a future L-band data link

Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações

Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species

Size-selective fishing is expected to affect traits such as individual growth rate, but the relationship between the fishery-linked selection differentials and the corresponding phenotypic changes is not well understood. We analysed a 25-year monitoring survey of sympatric populations of the two Alpine whitefish Coregonus albellus and C. fatioi. We determined the fishing-induced selection differentials on growth rates, the actual change of growth rates over time, and potential indicators of reproductive strategies that may change over time. We found marked declines in adult growth rate and significant selection differentials that may partly explain the observed declines. However, when comparing the two sympatric species, the selection differentials on adult growth were stronger in C. albellus while the decline in adult growth rate seemed more pronounced in C. fatioi. Moreover, the selection differential on juvenile growth was significant in C. albellus but not in C. fatioi, while a significant reduction in juvenile growth over the last 25 years was only found in C. fatioi. Our results suggest that size-selective fishing affects the genetics for individual growth in these whitefish, and that the link between selection differentials and phenotypic changes is influenced by species-specific factors.

An investigative study on the effects of black fly (diptera: simuliidae) sugar meals on reproductive success and parasite transmission /

Black flies are opportunistic sugar-feeders. They take sugar meals from Homopteran honeydew secretions or plant nectars, depending on availability. Homopteran honeydew secretions contain both simple and complex carbohydrates while plant nectars contain primarily simple carbohydrates. In order to determine whether honeydew secretions offer more energy than plant nectars to their insect visitors a study of wild-caught black flies was undertaken in Algonquin Provincial Park, Canada during the spring of 1 998 and 1 999. It was hypothesized that female black flies maintained on honeydew sugars will survive longer, produce more eggs and have a greater parasite vectoring potential than those maintained on artificial nectar or distilled water. Results demonstrated that: (1) host-seeking female Prosimulimfuscum/mixtum and Simulium venustum maintained on artificial honeydew did not survive longer than those maintained on artificial nectar when fed ad libitum; (2) fiiUy engorged S. venustum and Simulium rugglesi maintained on artificial honeydew did not produce more eggs than those maintained on artificial nectar when fed ad libitum; and (3) S. rugglesi did not have a greater vectoring potential of Leucocytozoon simondi when maintained on artificial honeydew as opposed to artificial nectar when fed ad libitum. However, all flies maintained on the two sugars (artificial honeydew and artificial nectar) survived longer, produce more eggs and had greater vectoring potential than those maintained on distilled water alone.

Behavioural characteristics in phylogenetics : a case study using black fly (Diptera: Simuliidae) cocoon spinning behaviour

1-1 is torically, the predominan t method of reconstructing phylogenies has been through the use of morphological characters. There are new techniques now gaining acceptance, including molecular techniques al1d chromosomal information. Altl10ugh the study of behaviour has been used in a comparative framework, these analyses have, historically, been based on intuition. Hennig (1966) devised a neV\' method of reconstructing phylogenies which provided a 110ncircular method for formulating, testing and refining phylogenies. Subsequent s)Tstematists had virtually abandoned ecological and beha\lioural data as primary indicators of phylogenetic relationships (Brooks and McLennan 1991). Therefore, in a modern cladistic framework (sensu Hennig) the analysis of behavioural traits remains underrepresented as a method of reconstructing phylogenies. This thesis will reconstruct the phylogeny for species of black flies (Diptera: Simuliidae), using two steps. The first step is to thoroughl)' understand and explain the cocoon spinning in black fly larvae. There have bee115 previous descriptions of cocoon spinning, but all were incomplete or erroneous. The advances in technology, including video recorders and VCRs, have allowed this behaviour to be analyzed in great detail in 20 different species. A complete description of the cocoon spinning of Simulium \littatum is given. This description will be used as a template for the other species observed. The description and understanding of cococ)n spinning was the first step in undertaking a phylogenetic analysis using this behaviour. The behaviour was then broken down and analyzed, revealing 23 characters, 3 either qualitative and quantitative in nature. These characters were assessed in a cladistic framework (sensu Hennig) and a phylogenetic tree was reconstructed with a e.I of 0.91 and an R.I. of 0.96. This phylogenetic tree closely resembles a previously established pllylogenetic tree produced from morphological and cytological information. The importance of this result is the indication that, contrary to some authors, behavioural characters, if used properly, can add very informative characters to a data set.