Des populations tolérante (métallicole: M) et sensible (non-métallicole: NM) d’Agrostis capillaris L. ont été exposées à des doses croissantes de Cu (1-50 μM) pour étudier la tolérance au Cu par une approche pluridisciplinaire. Selon les paramètres phénotypiques (biomasse, longueur des feuilles et symptômes visuels), les plantes M ont une meilleure croissance aux expositions supérieures à 10 μM Cu. Les concentrations en Cu des tissus reflètent une rétention racinaire (phénotype d’exclusion) et une réduction de la translocation vers les feuilles quand le stress augmente. En excès de Cu, le protéome soluble racinaire présente des altérations du métabolisme énergétique chez M et NM, plus marquées chez NM (glycolyse, cycle de Krebs /phosphorylation oxydative). Le protéome foliaire indique des impacts sur les phases claires et obscures de la photosynthèse chez M et NM, et un besoin plus important en acides aminés soufrés (augmentation des cystéine et méthionine synthases). Chez NM, l’augmentation d’enzymes de la glycolyse, de la voie des pentoses phosphates et du cycle de Calvin indiquent un besoin énergétique accru, tandis que la stimulation des chaperonnes et des processus de synthèse protéique suggère des impacts sur le métabolisme des protéines et celle des enzymes redox un stress oxydatif plus fort. Plusieurs protéines, surexprimées ou accumulées, interviendraient dans la tolérance au Cu chez M, en protégeant le métabolisme des protéines (HSP70, racines et feuilles) et en augmentant les mécanismes anti-oxydants (ascorbate péroxydases), de détoxification (GST et aldéhyde déshydrogénase) et de protéolyse (peptidase et protéasomes, racines). / Cu-tolerant (metallicolous: M) and sensitive (non-metallicolous: NM) populations of Agrostis capillaris L. were exposed to increasing Cu concentrations (1-50 μM) to investigate Cu tolerance by a pluridisciplinary approach. Phenotypic parameters (biomass production, shoot length, and visual symptoms) indicated a higher growth and a better fitness of M plants over 10 μM Cu. Plant Cu concentrations indicated root Cu retention (‘excluder’ phenotype) and a reduced root-to-shoot translocation with increasing Cu stress. Based on root soluble proteome energy metabolism was altered by Cu excess in both populations with stronger impacts in NM (glycolysis, Krebs cycle/oxidative phosphorylation). Changes in shoot proteome showed impacts on both light dependent and independent photosynthesis phases in both populations, and an enhanced need in S-containing amino-acids (up-regulation of cysteine/methionine synthases). In NM leaves, increase of enzymes involved in glycolysis, pentose phosphate pathway and Calvin cycle indicated a stimulation of energy metabolism, while enhanced protein synthesis processes and protein chaperones suggested impacts on protein metabolism and increase of redox enzymes indicated a higher oxidative stress. Several over-expressed or accumulated proteins may be pivotal for Cu tolerance in M plants, for protecting protein metabolism (Heat shock protein 70kDa, roots and leaves), increasing anti-oxidative (ascorbate peroxidases, roots) – detoxification (Glutathione S-transferase and aldehyde dehydrogenase, roots) and proteolysis (peptidase and proteasome subunits) processes.

In the southeastern United States, skimmer trawls, pusher-head trawls, wing nets, and small try nets (headrope length less than 12-ft (3.66-m)) are exempt from using a turtle excluder device (TED) and instead must adhere to tow time restrictions as a mode to mitigate sea turtle bycatch. However, observer and stranding data indicate that these tow times may often be exceeded and result in mortality of sea turtles. The National Marine Fisheries Service (NMFS) published a notice of proposed rulemaking in December 2016 to extend TED requirements to other trawl types, however there has been limited development of specialized TEDs for these smaller trawls. In anticipation of a regulatory change, we developed and identified multiple versions of a top-opening TED with a minimum width of 28-in (71-cm) and height of 24-in (61-cm) as the best option for small trawl gears. Prototypes were initially equipped within small try nets and tested for gear performance and sea turtle exclusion in Panama City, Florida. The final designs were then tested for target shrimp retention, bycatch reduction, and general usability of TEDs in the commercial fisheries. A paired comparison test was conducted in 8-ft (2.44-m) and 10-ft (3.05-m) try nets aboard the NMFS R/V Caretta, three commercial skimmer trawls in vesselsFarfantepenaeus duorarum) fishery. There was a general reduction of shrimp and bycatch averaging from a minimum loss of 3.31% in the Miami wing net fishery (FV FL-01) to 22.07% in the skimmer trawl fishery (FV LA-01). This dissertation research indicates that TEDs can function properly in small trawl types, however additional studies are recommended to minimize the shrimp loss and improve the overall TED effectiveness specific to each fishery and trawl type evaluated.