Species point records from 1978 UCNW Glaslyn/Dwyryd estuary littoral sediment survey

Benthic survey of Glaswyn/Dwyryd Estuary sandflats, adjacent to Morfa Harlech NNR. The estuary is extensive at 8.2 km. Sediments are of marine sand collected by Langshore drift in Coreligan Bay, and accretion in the estuarine area. Two obvious faunal trends ar apparent when the main part of the estuary. A salinity trend restricting Anguilla tenuis and Bathyporeia pelagica to low ground near the mouth and a sand/mobility/shelter/height based trend from the sparse fauna of the sandy low water channels to the organically richer muddy salt marsh fringe. The basin just above Portmadoc town bridge is an especially muddy artificial habitat sheltered by embankments and adjacent to the town sewage works. This mud seems to hold Nereis diversicolor, Prionospio cirifera and oligochaetes.

对位于莫尔法哈雷奇国家自然保护区附近的格拉斯温/德维德河口沙滩进行了底栖调查。该河口范围广阔，全长达8.2公里。沉积物主要为海洋沙质，由科尔利甘湾的沿岸漂移沉积在河口区域，并在此处逐渐堆积。当观察河口主体部分时，可观察到两种明显的生物群落趋势。一是盐度趋势，限制了狭鳕（Anguilla tenuis）和浮游桡足类（Bathyporeia pelagica）在河口入口附近低地的分布；二是基于沙质、流动性、庇护所和高度的趋势，从稀疏的沙滩低水道生物群落到有机物质更为丰富的淤泥盐沼边缘。波特马多克镇桥上方的水域是一个特别泥泞的人工栖息地，由堤坝保护，且邻近城镇污水处理厂。这种淤泥似乎容纳了多色钩虾（Nereis diversicolor）、圆头管 Worm（Prionospio cirifera）和寡毛类动物。