Bulletin of the Southern California Academy of Sciences
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Open Access journal
ISSN (Print) 0038-3872
Published by Southern California Academy of Sciences [1 journal]
PubDate: Mon, 13 Jul 2015 10:23:14 PDT
- Nelson’s big horn sheep (Ovis canadensis nelsoni) trample
Agassiz’s desert tortoise (Gopherus agassizii) burrow at a
California wind energy facility
Authors: Mickey M. Agha et al.
PubDate: Mon, 13 Jul 2015 10:23:11 PDT
- A Young-of-the-Year Giant Sea Bass, Stereolepis gigas Buries Itself in
Sandy Bottom: A Possible Predator Avoidance Mechanism
Authors: Michael C. Couffer et al.
PubDate: Mon, 13 Jul 2015 10:23:09 PDT
- Recent decline of lowland populations of the western gray squirrel in the
Los Angeles area of southern California
Authors: Daniel S. Cooper et al.
Abstract: We provide an overview of the distribution of lowland and otherwise isolated populations of the western gray squirrel (Sciurus griseus) in the Los Angeles area of southern California, an area that has experienced a recent and ongoing invasion by the non-native eastern fox squirrel (Sciurus niger), an urban-adapted species introduced a century ago. Away from its strongholds in the western Santa Monica Mountains, San Gabriel Mountains, and Santa Ana Mountains, the western gray squirrel is resident locally in both the Santa Susana and the Verdugo Mountains, in Griffith Park, in low hills at the eastern periphery of the San Gabriel Valley and in Claremont, and along the Santa Ana River canyon near Yorba Linda. It also persists east of the Los Angeles area in residential areas of Redlands and Yucaipa, which as of 2014 are still outside the range of the eastern fox squirrel. Here we document several gray squirrel extirpation events within its lowland range, and discuss factors influencing its persistence and its extirpation.
PubDate: Mon, 13 Jul 2015 10:23:07 PDT
- Identical Response of Caged Rock Crabs (Genera Metacarcinus and Cancer) to
Energized and Unenergized Undersea Power Cables in Southern California,
Authors: Milton S. Love et al.
Abstract: Energy generation facilities (i.e., wave and wind) are being sited in offshore marine waters. The electricity generated from these facilities is transmitted to shore through cables carrying alternating or direct current. This current produces an electromagnetic field (EMF) that is emitted from the cable. Concerns have been voiced regarding how marine organisms, in this instance crabs, respond to the EMF emitted by submarine power cables. Two submarine cables, one energized and the other unenergized, and separated by about 7 m, were used in the experiment. Crabs (Metacarcinus anthonyi (Rathbun, 1897) and Cancer productus (Randall, 1839)) were placed in plastic perforated boxes secured to the sea floor with one end in contact with one of the two cables. After one hour and 24 hours, scuba divers ascertained the position of the crabs within the boxes, these positions designated as either “near-half” or “far-half.” EMF readings were taken on the floor of each box at the edge closest to the cable and on the floor of that box furthest from the cable at one and 24 hours. Within the boxes, EMF levels were between 46.2–80.0 microteslas next to the cable and
PubDate: Mon, 13 Jul 2015 10:23:04 PDT
- Soil Organic Carbon and Nitrogen Storage in Two Southern California Salt
Marshes: the Role of Pre-restoration Vegetation
Authors: Jason Keller et al.
Abstract: Soil organic carbon and nitrogen storage represent important ecosystem services provided by salt marshes. To test the importance of vegetation on soil properties, we measured organic carbon, total nitrogen, and belowground biomass in two southern California salt marshes. In both marshes, cores were collected from areas which differed in dominant vegetation cover prior to the restoration of tidal influence. There were no differences in organic carbon or total nitrogen density between vegetation classes at either site; however, a relationship between belowground biomass and soil organic carbon suggests that vegetation may influence soil properties.
PubDate: Mon, 13 Jul 2015 10:23:02 PDT
- Removal Efforts and Ecosystem Effects of Invasive Red Swamp Crayfish
(Procambarus clarkii) in Topanga Creek, California
Authors: Rosi Dagit
Abstract: Red swamp crayfish (Procambarus clarkii) were first recorded in Topanga Creek in 2001. With the onset of drought in Southern California resulting in low flows in 2011-2014, the population rapidly increased. Within the Santa Monica Mountains, P. clarkii has been linked to diminishing numbers of California newt (Taricha torosa), a species of special concern (Kats et al. 2013). To address these concerns, a student-based citizen science program was conducted from November 2013 through February 2014 to remove crayfish from a 200 meter reach of Topanga Creek. The following data was collected and compared between the removal reach and an upstream, adjacent 200 meter non-removal reach (control): water quality (temperature, salinity, pH, conductivity, dissolved oxygen, turbidity), nutrient levels (nitrate, nitrite, ammonia, orthophosphate), benthic macroinvertebrate community metrics, crayfish demographics and catch-per unit effort (removal reach only). The results indicate that red swamp crayfish presence or removal does not affect water quality or nutrient levels in Topanga Creek. However, benthic macroinvertebrate communities were significantly different between reaches; the presence of crayfish correlated with lower BMI abundance, a higher proportion of tolerant taxa, and lower feeding group complexity.
PubDate: Mon, 13 Jul 2015 10:23:00 PDT
- Possible Stock Structure of Coastal Bottlenose Dolphins off Baja
California and California Revealed by Photo-Identification Research
Authors: Richard H. Defran et al.
Abstract: Boat-based photo-identification research has been carried out on bottlenose dolphins in the eastern North Pacific coastal waters of northern Baja California, Mexico and southern and central California, USA from 1981 to 2001. Within these waters, bottlenose dolphins routinely travel back and forth between coastal locations while generally staying within a narrow coastal corridor of about 1 km or less from the shore. Inter-area match rates between 616 dolphins photo-identified in Ensenada, San Diego, Orange County and Santa Barbara between 1981-2000 averaged 76%. To explore possible southern range limits for these California coastal dolphins, photo-identification surveys were carried out in the coastal waters off San Quintín, Baja California, Mexico between April-August 1990 (n=8) and July 1999 to June 2000 (n=12). The 207 individual dolphins identified in San Quintín were compared to the 616 dolphins identified in the California coastal study areas (CCSAs) of Ensenada, San Diego, Orange County and Santa Barbara. The inter-area match rate between San Quintín and the CCSAs was 3% (n=7). This low rate contrasts sharply with the much higher average match rate of 76% observed between the CCSAs. These differences in match rates suggest that both a California coastal stock and coastal Northern Baja California stock may exist, with only a limited degree of mixing between them.
PubDate: Mon, 13 Jul 2015 10:22:58 PDT
PubDate: Tue, 03 Feb 2015 13:58:02 PST
- Clarifying the Northern Extent of Diamond Stingray (Dasyatis dipterura) in
Authors: Eric Miller et al.
PubDate: Tue, 03 Feb 2015 13:58:00 PST
- Fishes of Marine Protected Areas Near La Jolla, California
Authors: Philip A. Hastings et al.
Abstract: Abstract.—The marine waters surrounding La Jolla, California have a diverse array of habitats and include several marine protected areas (MPAs). We compiled a list of the fish species occurring in the vicinity based on records of specimens archived in the Marine Vertebrate Collection (MVC) of the Scripps Institution of Oceanography (SIO). Collection of fishes from La Jolla in the MVC started in 1905, but greatly accelerated in 1944 when Carl L. Hubbs moved to SIO. By 1964, 90% of the 265 species recorded from the area had been collected and archived in the MVC. The fishes of La Jolla are dominated by species whose center of distribution is north of Point Conception (111 species), or between there and Punta Eugenia (96), with fewer species with southern distributions (57), and one exotic species. Reflecting the diversity of habitats in the area, soft-substrate species number 135, pelagic species 63, canyon-dwelling species 123 (including 35 rockfish species of the genus Sebastes), and hard-bottom species 140. We quantified the abundance of the latter group between 2002 and 2005 by counting visible fishes in transects along the rocky coastline of La Jolla, both within and adjacent to one of the region's MPAs. In 500 transects, we counted over 90,000 fishes representing 51 species. The fish communities inside and outside of the MPA were similar and, typical of southern California kelp forests, numerically dominated by Blacksmith, Chromis punctipinnis (Pomacentridae), and Señorita, Oxyjulis californica (Labridae). Natural history collections such as the MVC are important resources for conservation biology for determining the faunal composition of MPAs and surrounding habitats, and documenting both the disappearance and invasion of species.
PubDate: Tue, 03 Feb 2015 13:57:58 PST
- Avian Predators Target Nocturnal Runs of the Beach-Spawning Marine Fish,
California Grunion, Leuresthes tenuis (Atherinopsidae)
Authors: Karen L M Martin et al.
Abstract: Tidal cycles are important cues for many marine and near-shore animals. Birds that typically feed at the water’s edge during daytime low tides are rarely present on beaches at night. However, we found that several species of diurnal birds reliably attended and preyed upon the nocturnal spawning runs of a marine fish, Leuresthes tenuis, the California Grunion (Teleostei: Atheriopsidae) on the shores of Malibu Lagoon State Beach (MLSB), Los Angeles County, California, USA. Avian hunters of California Grunion included Black-crowned Night Heron Nycticorax nycticorax, Great Blue Heron Ardea herodias, Snowy Egret Egretta thula, and Western Gull Larus occidentalis. Spawning runs of California Grunion are synchronized by tides within a narrow window of time, two hours following the semilunar high tides of full and new moons. These silverside fish aggregate en masse predictably, and further increase their vulnerability by fully emerging from the water while spawning. This allows the birds to capture California Grunion terrestrially. On nights when spawning runs of California Grunion could potentially occur, birds were present on MLSB, often before the fish began to run onto shore. Number of birds was high for the nights of likely runs whether after full or new moons, whether or not the fish appeared, but not on other nights. We suggest that birds rely on tidal cues to anticipate spawning runs of California Grunion, not the amount of moonlight or the actual presence of fish on shore. Shorebirds were more likely to forage at night at sites close to their upland roosting and nesting areas than at sites with less upland habitat. Observers on nearby Will Rogers State Beach and Topanga State Beach saw comparable spawning runs of California Grunion but reported significantly fewer avian predators. At MLSB, when tide conditions were right, avian predators appeared on the beach with even greater predictability than did their potential prey.
PubDate: Tue, 03 Feb 2015 13:57:54 PST
- Pilot California Spiny Lobster Postlarvae Sampling Program: Collector
Authors: Eric Miller
PubDate: Tue, 03 Feb 2015 13:57:53 PST
- Male Mating Posture and Breeding Coloration of the Temperate Marine
Tubesnout Aulorhynchus flavidus
Authors: Michael J. Schram et al.
Abstract: Body posture, vocalizations or coloration play variable roles in the mating success and social dominance of species. Increasing our knowledge of how these specific features function helps improve our understanding of evolutionary trends and the ecological associations of species with their habitats. Through observations and still photography of the temperate marine tubesnout Aulorhynchus flavidus in display at the Aquarium of the Pacific in Long Beach, California during early May, 2013 we documented male mating behavior, a previously uncharacterized aspect of this species. Males position their body in a declined position from tail to head facing a prospective female, undulating their bright red pelvic fins for courtship display. Although male pelvic fins appear to be red year-round, their vibrancy seems to increase during peak breeding. Male heads are dark blue to black with a prominent iridescent blue patch on the snout and similar patches down the length of the body in contrast to females that are a drab brown throughout. While bright colors are often uncommon in temperate systems, it is present in other temperate gasteriform fishes suggesting red coloration may have developed in a common ancestor and has persisted over time. However, research has shown variable success relative to body coloration in other gasteriform species under interspecific competition for nesting space. These results may suggest variable selective pressures for body coloration under differing habitat conditions and may result in fluctuating prominence over evolutionary time.
PubDate: Tue, 03 Feb 2015 13:57:51 PST
- Larval Duration, Settlement, and Larval Growth Rates of the Endangered
Tidewater Goby (Eucyclogobius newberryi) and the Arrow Goby (Clevelandia
ios) (Pisces, Teleostei)
Authors: Brenton T. Spies et al.
Abstract: The early life history of the federally endangered tidewater goby (Eucyclogobius newberryi) and its sister species the arrow goby (Clevelandia ios) has been poorly documented to date. Both are endemic to estuarine habitats throughout the California coast, however, habitat use differs between these two species. The arrow goby is commonly found in fully marine tidal bays and mudflats. The tidewater goby, however, prefers lagoons with some degree of seasonal isolation from the sea. Here, we used otoliths to examine the larval duration, size at settlement, and growth rates of newly settled gobies collected from 18 estuaries in California. The tidewater goby had a larval duration that was ~2 days shorter than the arrow goby (23.95 vs. 26.11 days, respectively), but a larger size at settlement based on back-calculated size (12.38 vs. 10.00 mm SL) due to a faster larval growth rate (2.86 vs. 2.60 μm/day-1). There are several reasons that could explain these differences in larval traits, such as differences in temperature or food resources between the two estuary types, or the faster, annual life cycle of the tidewater goby relative to the arrow goby.
PubDate: Tue, 03 Feb 2015 13:57:49 PST
- Expansion of the non-native Mississippi Silverside, Menidia audens
(Pisces, Atherinopsidae), into fresh and marine waters of coastal southern
Authors: Camm C. Swift et al.
Abstract: Abstract--Mississippi Silversides, Menidia audens, were first recorded in southern California reservoirs and nearby outflows in the late 1980s and early 1990s. In 1997-2000 they were taken in King Harbor, Redondo Beach,and in 2000 in the Santa Ana River. By 2005-2006 they were found in several other coastal drainages from the San Gabriel River in Orange and Los Angeles counties northward to Arroyo Burro, Santa Barbara County. Initial invasion was via the California Aqueduct in the late 1980s and early 1990s and more recently dispersal has taken place along the southern California coast. The records from King Harbor occurred for a relatively short period, mid-1997-mid-2000 (mostly 1997 and 1998) before they were established in coastal drainages. Their impact on native species is not known but on some occasions Mississippi Silversides have outnumbered native Topsmelt, Atherinops affinis, in small coastal lagoons estuaries. Mississippi Silversides are known to prey on eggs and larvae of other fishes and could be increasing predation on small native animals as well as serving as prey for larger piscivores like steelhead and terns. .
PubDate: Tue, 03 Feb 2015 13:57:46 PST
- Notes on Euphoria fascifera (Leconte) (Coleoptera: Scarabaeidae) in
Authors: E. L. Sleeper et al.
PubDate: Thu, 22 Jan 2015 10:10:26 PST
- Notes on Atractocerus brasiliensis Lepeltier & Serville (Coleoptera:
Telegusidae) in Western Mexico
Authors: Elbert L. Sleeper
PubDate: Thu, 22 Jan 2015 10:10:25 PST
- Notes on the Biology of Blepharocera micheneri and Philorus yosemite
(Diptera: Blepharoceridae) in Southern California
Authors: David L. Gibo
PubDate: Thu, 22 Jan 2015 10:10:23 PST
- Observations of the Mating Process of the Spider Crab Pugettia producta
Authors: Jens W. Knudsen
PubDate: Thu, 22 Jan 2015 10:10:22 PST