Cetaceans Research Paper

Cetaceans are an order of highly adapted, fully aquatic mammals (Wells 2010). Historically all cetaceans were once hunted extensively across the globe, causing major population declines, the Atlantic Gray Whale consequently became extinct. Some reached near extinction such as the Blue Whale while other species have more recently started to recover and scientists are slowly seeing population increases, for instance The Humpback whale (Ruegg et al. 2012). This mass population decline is often associated with larger mysteceti whale species and sperm whales, the largest odonticeti. Less is known historically about the smaller odonticeti whales and dolphins but there is evidence they were also hunted (Brito & Vieira 2010). More recently however increasing anthropogenic factors are negatively

2006; Law et al. 2012). These burdens put a strain on the internal organs of an animal, compromise immune responses (Bustamante et al. 2003) and inhibit fetal development (Law et al. 2012). Ingested plastic has been found in the stomachs of various stranded cetacean species, small micro-plastic pieces are suspended in ocean water columns and mistaken as prey by fish which are then ingested by cetaceans, larger plastics such as polythene have also been found ingested directly and can cause blockages so animals slowly starve to death (Baulch & Perry 2014). Marine noise has been linked to mass strandings of cetaceans and can be attributed to naval sonar activities within a localised area (Jepson et al. 2013). With increasing boat traffic the risk of ship strikes have also increased (Sierra et al. 2014). In Cornwall the most common cause of death in stranded cetaceans is bycatch, the two most common cetaceans to strand are harbour porpoise (Phocoena phocoena) and short beaked common dolphins (Delphinus delphis)(Clear et al.