Evaluation of fish pots as a feasible fishing method in Irish waters, with specific reference to the physiological effects of common and alternate pots on the lesser spotted dogfish (Scyliorhinus canicula).

Finfish pots have emerged as a “responsible” gear, when used in combination with conservational and technical measures to sustain fisheries. Previous trials in Irish waters have offered no published reported data and so three designs tested in the current study provide new information on this gear. The most successful traps in terms of fish catch were rigid steel framed rectangular pots used to target Conger eel. Although commercial yield was low (0.2 per trap haul), potential existed for a viable pot fishery. Deployment and storage of Norwegian floating pots was conducted with relative ease but performance in the water was poor resulting in loss of gear. Catch returns were notable even though effort was restricted as mega-faunal by-catch was a problem, which lead to ending this trial. From these initial trials it was evident that catch rates were low compared to established Norwegian fisheries (3.6 cod per pot), which resulted in the utilisation of pots, already established in the crustacean fishery, to find species readily accessible to pot capture. Although fished and designed differently, these gears provided an opportunity to establish the benefits of pot fishing to fish quality and to determine the effects on by-catch. The fishing effects of three catching methods (pots, angling and trawl) and the effects of air exposure on the physiological status of a common by-catch, the lesser spotted dogfish Scyliorhinus canícula (L.) were examined using a range of physiological biomarkers (plasma catecholamine, glucose, lactate, muscle pH and muscle lactate). Physiological responses of fish to an emersion stress regime resulted in a significant metabolic disturbance in groups, but may not have weakened the overall health of these fish, as signified in the revival of some metabolites. Plasma glucose and lactate concentrations did not however recovery to baseline levels indicating that to achieve an accurate profile, responses should be determined by a suite of biomarkers. Responses did not demonstrate that samples from the pots were significantly less stressed than for the other two methods; angling and trawling, which are in contrast to many other studies. Employment of finfish potting therefore in Irish waters needs further consideration before further promotion as a more responsible method to supplement or replace established techniques.

Design of a bifurcated stent graft, with its accompanying delivery system.

Abdominal Aortic Aneurysms (AAA) haemorhaging is a life-threatening disease. An aneurysm is a permanent swelling of an artery due to a weakness in its wall. Current surgical repair involves opening the chest or abdomen, gaining temporary vascular control of the aorta and suturing a prosthetic graft to the healthy aorta within the aneurysm itself The outcome of this surgical approach is not perfect, and the quality of life after this repair is impaired by postoperative pain, sexual dysfunction, and a lengthy hospital stay resulting in high health costs. All these negative effects are related to the large incision and extensive tissue dissection. Endovascular grafting is an alternative to the standard surgical method. This treatment is a less invasive method of treating aortic aneurysms. It involves a surgical exposure of the common femoral arteries where the stent graft can be inserted through by an over-the-wire technique. All manipulations are controlled from a remote place by the use of a catheter and this technique avoids the need to directly expose the diseased artery through a large incision or an extensive dissection. The proposed design method outlined in this project is to develop the endovascular approach. The main aim is to design an unitary bifurcated stent graft (1 e- bifurcated graft as a single component) to treat these Abdominal Aortic Aneurysms. This includes the delivery system and deployment mechanism necessary to first accurately position the stent graft across the aneurysm sac and also across the iliac bifurcation, and secondly fix the stent graft in position by using expandable metal stents. Thus, excluding the aneurysm from the circulation and therefore preventing rupture. Miniaturisation is a critical aspect of this design, as the smaller the crimped stent graft the easier to guide through the vascular system to the desired location. Biocompatibility is an important aspect. The preferred materials for this prosthesis are to use Shape Memory Alloys for the stent and a multifilament fabric for the graft. A taper design is applied for the geometry as this gives a favourable flow characteristic and reduced wave reflections. Adequate testing of the stent graft to prove its durability and the ease of the method of deployment is a prerequisite. A bench test facility has being designed and build to replicate the cardiovascular system and the disease in question aortic aneurysms at the iliac bifurcation. The testing here shows the feasibility of the proposed delivery system and the durability of the stent graft across the aneurysm sac. Finally, these endovascular treatments offer the economic advantage of short hospital stays or even treatment as an outpatient, as well as elimination of the need for postoperative intensive care The risk of developing an aneurysm increases with age, that is one of the mam reasons to look for less invasive ways of treating aneurysms. Consequently, there is enormous pressure to develop and use these devices rapidly.