Survey of imposex in Nucella lapillus as an indicator of tributyltin pollution in Northern Irish coastal waters, 2004 to 2017.

Tributyltin (TBT) was a commonly used biocide in anti-fouling paints for marine vessels, however, it had negative impacts on non-target species, including causing imposex in dogwhelks (Nucella lapillus). Since the 1980s, legislation has been introduced to curtail its usage, culminating in a ban by the International Maritime Organisation (IMO) in 2008. In 2004 a national imposex monitoring network was established in Northern Ireland to determine the level and extent of TBT pollution. The level of imposex in N. lapillus was assessed according to the degree of male sexual development in the female using three measures: percentage of imposex-affected females (%I), the relative penis size index (RPSI), and the vas deferens sequence index (VDSI). All sites showed improvement since the initial survey with a reduction in imposex and an improvement in ecological quality under the classification of the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR).

Fish trophic structure in estuaries, with particular emphasis on estuarine typology and zoogeography.

A comparative analysis of the fish trophic structure was undertaken on some 190 South African estuaries spanning three zoogeographic regions and incorporating three broad estuarine types. Fish biomass trophic guild compositions and biomass trophic spectrum profiles were analysed using multivariate statistical techniques and included both inter-regional (zoogeographic) and intra-regional (estuarine typology) comparisons. Differences in the fish trophic structure of the various estuary types within each zoogeographic region were observed; these were linked to the relative biomass contribution of the various trophic guilds and also to differences in biomass trophic spectrum profiles of the fishes in each estuary type within each region. In spite of these differences in trophic structure, all estuaries were dominated by detritivores, which suggests that the main food source (detritus) is similar in all biogeographic regions. Preliminary indications are that a similar dependence by estuary-associated fishes on detritus food sources exists on a global basis but that detailed studies are required in order to confirm this assertion.

An alternative to synthetic aortic grafts using jejunum.

Synthetic materials currently used for arterial grafts can provoke serious complications such as infection, rejection, and incomplete reendothelialization. Porcine small intestinal submucosa (SIS) allografts (homografts) may not share these disadvantages yet still may provide an effective graft alternative. This study was designed to provide additional information concerning the performance of this material when used as an allo-patch graft. A porcine model was selected to enable hemodynamic comparisons to the adult human physiology. Slaughterhouse small intestine was used to prepare the SIS graft material. A well-vascularized section ofjejunum was resected, rinsed, and maintained in 0.9% NaCl solution containing 10% gentamicin. The graft was prepared by removing the serosal layer, inverting the material, and discarding the mucosal surface in a similar manner. The remaining submucosa and stratum compactum constituted the graft material and was subdivided into sizes from 1.5 to 3.0 cm2 tacked to foil for manageability, and was returned to the gentamicin solution. The surgery was initiated with a femoral arterial line in the anesthetized swine, followed by isolation and preparation of the infrarenal aorta for grafting. Cross-clamps were applied and a 1.0 x 1.5-cm section of aortic wall was resected. Two sides of allograft were freed from the foil and sewn into the aorta. Then the remaining sides were removed from the foil and final graft placement was completed. The graft was harvested at postoperative day 28 and presented for microscopic examination. Results confirmed that reendothelialization with neovascularization had occurred during this interval.