Southern occurrence of the sand sole (Psettichthys melanostictus)

Abstract

The geographic and depth ranges of marine fishes commonly reflect their physiological preferences (Portner et al., 2010). Given the wide availability of habitats along the California coastline, biogeographic range extensions of many species have been observed to occur periodically, most frequently during periods of short-term oceanographic temperature fluctuation. Over the last 30 years, these range extensions in California have mostly been poleward expansions as ocean temperatures have warmed or through largescale oceanographic anomalies such as Californian-El Nino conditions (Lea and Rosenblatt, 2000). Many of the recently documented range extensions in southern California have been associated with thermal power plant cooling water intakes or discharges, often due to the increased sampling and/or the presence of greater-thanambient water temperatures near the discharges (Pondella, 1997; Lea and Rosenblatt, 2000; Miller and Curtis, 2008). In addition to the thermal discharge, the cooling water system entrains material, including fishes, with the cooling water drawn into the system. The cooling water is filtered through traveling screens with a nominal square mesh of 10-mm to prevent debris from passing farther into the system and potentially clogging downstream condensers. Fish impingement upon these traveling screens is routinely monitored to provide a representative accounting of the fishes taken in by the cooling water system, and an opportunity to collect random tourist species. Sand sole (Psettichthys melanostictus) reportedly ranges from the Southeastern Bering Sea, Alaska to Newport Beach, California in depths ranging from the intertidal zone out to 325 m (Love et al., 2005). Museum records contain numerous specimens taken in northern California with only three lots collected offshore of Ventura County, California at the southernmost extent (Fishnet2 2011). Surprisingly, no records were found for collections in the Santa Barbara, California area despite substantial areas of suitable habitat. Reviews of the Santa Barbara Natural History Museum (SBNHM 2011) ichthyology records found no sand soles in the collection. Fitch and Schultz (1978) detailed two fish taken in the southern Santa Monica Bay in the mid-1970s during impingement sampling at Scattergood Generating Station in El Segundo, California and the Redondo Beach Generating Station in Redondo Beach, California. The Redondo Beach sample had set the southern range limit for this species at the time. Slightly farther southwards, several sand sole were caught by recreational anglers fishing off the Balboa Pier during the 1980s (M. Love, unpubl. data), which had served as the impetus for the current southern range endpoint. One collection that has gone largely unreported is recorded in the Museum of Comparative Zoology (MCZ 2011) as collected in San Diego County, California during the mid-1800s (Lot 25988) and has not been previously included in the biogeographic distribution of the sand sole (Love et al., 2005; Horn et al., 2006). This sample, however, has limited information regarding its collection. Careful