Ricardo Searcy-Bernal

Autonomous University of Baja California | UABC · Instituto de Investigaciones Oceanológicas, Ensenada, Mexico

Co-culture of abalone and sea cucumber can result in benefits. This study investigated for 131 days the growth of juvenile red abalone (Haliotis rufescens) co-cultured with two densities of warty sea cucumbers (Apostichopus parvimensis). The initial mean (± SE) shell length of 1080 red abalone was 26.74 ± 1.04 mm, with a wet weight of 5.64 ± 0.12 g...

In recent decades, global abalone aquaculture has significantly increased, while wild abalone fishery landings have decreased drastically, shifting production from fishing to farming. In California (USA) and Baja California (Mexico), overfishing and climate change- linked diseases are thought to be responsible for mass mortalities and significant d...

The effects of different diets on the survival, growth, food consumption, and conversion factor of juvenile red abalone (Haliotis rufescens) under tank culture conditions were investigated. The algae Macrocystis pyrifera, Gracilaria chilensis, and Sarcothalia crispata were administered as mixed diets, mono diets, or in rotation changing weekly. Add...

This study evaluated the potential to propagate asexually the brown sea cucumber Isostichopus fuscus by induction of transverse fission, and its ability to survive, grow and regenerate body parts into a whole animal. Two independent experiments were performed. Experiment 1: sixty-two adult animals (18.8 ± 0.2 cm and 368.1 ± 7.2 g) were cut six cent...

This study evaluated the potential to propagate asexually the brown sea cucumber Isostichopus fuscus by induction of transverse fission, and its ability to survive, grow and regenerate body parts into a whole animal. Two independent experiments were performed. Experiment 1: sixty-two adult animals (18.8 ± 0.2 cm and 368.1 ± 7.2 g) were cut six cent...

Adult Panopea globosa clams were conditioned in the laboratory during 8 weeks (mid Oct–Dec) under a decreasing temperature regime (22–18 °C) and using a semi-open recirculating system to investigate the effect of kelp meal (powdered Macrocystis pyrifera) or fish oil supplementation to live microalgal diets (w/w basis) on the live body weight (BW),...

The effect of different strategies of opening water flow on the survival and growth of Haliotis rufescens 9-d postlarvae was evaluated using a randomized block design with 3 replicates for 63 days. Larvae were settled (1.5 mM gamma-aminobutyric acid) in 2-L plastic vessels (total area, 701 cm 2) and were subjected to the following treatments: stati...

Abalone restocking in the peninsula of Baja California, Mexico, has been practiced for more than 2 decades by fishermen cooperatives. We describe the methods used to produce and release abalone larvae and seeds by these organizations, and provide their recent production statistics. From 2005 to 2011, 2.2 million seeds (>15 mm) and 692 million compe...

Three bacterial strains, GHrC11, GHrC13 and GHrC15, were isolated from an abalone postlarval culture system in a commercial farm at Baja California, México. The strains were phenotypically characterized and sequenced (16S rDNA). Strain GHrC11 was a Gram-positive coccobacillum, while strains GHrC13 and GHrC15 were Gram-negative bacilli. Strain GHrC1...

Recently recruited urchins from the same brood, but with different initial sizes, may respond differently to similar environmental factors. The aim of this study was to assess and compare the effects of starvation and diet on the survival, growth rates in size and weight, and gonad index among small and large sub-adult purple sea urchins, Strongylo...

During the 2008 season, 318 mt (meat weight) of abalone (Haliotis spp.) were commercially fished in Mexico. The species composition of the catch was H. fulgens (70.8%). H. corrugata (28.9%), and H. cracherodii (0.3%). During the past 5 y, total catches increased 29% as a result of the recovery of natural populations of the 2 main species. In partic...

Recently recruited urchins from the same brood, but with different initial sizes, may respond differently to similar environmental factors. The aim of this study was to assess and compare the effects of starvation and diet on the survival, growth rates in size and weight, and gonad index among small and large sub-adult purple sea urchins, Strong-yl...

We evaluated the effect of tetracycline (a fluorescent tag) and two different types of internal tags, Decimal Coded Wire Tags (CWT) and Passive Integrated Transponder tags (PIT) used alone or in combination on growth rates, survival, tag retention, and post-tagging stress of the purple sea urchin Strongylocentrotus purpuratus (Stimpson), under labo...

We evaluated the effect of tetracycline (a fluorescent tag) and two different types of internal tags, Decimal Coded Wire Tags (CWT) and Passive Integrated Transponder tags (PIT) used alone or in combination on growth rates, survival, tag retention, and post-tagging stress of the purple sea urchin Strongylocentrotus purpuratus (Stimpson), under labo...

Four–day–old postlarvae of the abalone Haliotis corrugata were exposed to different diatom densities (Navicula incerta, 0 to 8000 cells mm–2) under two illumination conditions: constant light (19–21 µmol quanta m–2 s–1) and darkness. The effect of these two factors on postlarval grazing rate, survival, and growth was evaluated. The experiment was c...

Four-day-old postlarvae of the abalone Haliotis corrugata were exposed to different diatom densities (Navicula incerta, 0 to 8000 cells mm-2) under two illumination conditions: constant light (19-21 imol quanta m-2 s-1) and darkness. The effect of these two factors on postlarval grazing rate, survival, and growth was evaluated. The experiment was c...

Abalone aquaculture is rapidly developing in Chile although this mollusc does not occur naturally in this country. The red abalone Haliotis rufescens was introduced in 1977 and the ezo abalone Haliotis discus hannai in 1982. After several years of research and development, the industry began in 1992 and Chile is currently the fifth producer of cult...

Metamorphosis induction and postlarval growth of the red abalone (Haliotis rufescens) were evaluated in a commercial farm of Baja California, México. This hatchery settles larvae with gamma-aminobutyric acid (GABA, 1-μM final concentration) and culture postlarvae in 250-L tanks placed in a four-story structure inside a building with artificial illu...

The effect of two light conditions (light at 10–13-μmol quanta/m2/s and darkness) in three water flow rates (0, 200, and 600 mL/min) on the survival, grazing, and growth rates of 6-day-old Haliotis rufescens postlarvae (pl) was evaluated. A factorial experiment with three replicates per treatment in blocks was conducted for 44 days in 2-L plastic c...

Traditional abalone culture is carried out in flow-through systems with water exchange rates between 200 and 2,400% of the total tank volume per day. These high volumes of water associated with abalone culture represents a constraint for the growth of this industry, and recirculating systems can become a viable alternative, because the water exchan...

Abstract— The induction of larval metamorphosis is a critical step in abalone Haliotis spp. culture. Recently, gamma-aminobutyric acid (GABA) has been used as an inducer by an increasing number of commercial hatcheries, because of its higher efficiency over other settlement methods. The conventional GABA concentration used is 1.0 micromolar as sugg...

Abalone (Haliotis spp.) postlarvae are cultured in systems that provide natural or artificial light to promote the growth of benthic diatoms that are grazed by postlarvae. Larger abalones (> 2 cm) grow better in dark conditions and the possibility that this is true for postlarvae is explored in this contribution. Two independent experiments with Ha...

The effect of increasing concentrations of Vibrio alginolyticus on survival of Mytilus galloprovincialis larvae was studied in a 48 h static bioassay in 1 l glass bottles. Five bacterial densities were tested ranging from 10(2) to 10(6) bacteria ml(-1). Larval survival and normality (veliger larvae with the typical D-shape) were evaluated after 48...

Survival and growth of Haliotis fulgens postlarvae (11 days old) were evaluated at four irradiance levels: 6, 24, 47 and 75 microensteins m À 2 s À 1 (AE). Experimental vessels were 1-l containers supplied with aeration and seawater flow. Four replicates per treatment were considered. Postlarvae were fed Navicula incerta, a cultured benthic diatom....

Grazing rates of Haliotis fulgens postlarvae of different ages (7, 15, 30, 45 and 60 days), feeding on the cultured diatom Navicula incerta, were estimated in 10 ml sterile plastic dishes previously inoculated with different densities of the diatom (100-4,000 cells/mm2). Postlarvae (3-7 per dish) were allowed to graze for two to three hours and vid...

This article describes attempts to estimate grazing rates of haliotid postlarvae. Two similar experiments with Haliotis rufescens postlarvae of different ages (2-30 days) were conducted. Postlarvae were placed into 10-mL containers previously inoculated with the benthic diatom Navicula incerta. Two hours later, video recordings at different magnifi...

Pathogenic bacteria may enter intensive husbandry systems by four routes: seawater system, air-borne contaminants, broodstock, and food supply. Sand and cartridge filters, as well as ultraviolet (UV) systems, are used in Baja California abalone (Haliotis spp.) farms to reduce and control the bacterial community. Viable heterotrophic bacteria (VHB)...

The pathogenicity of Vibrio alginolyticus on Haliotis rufescens veliger larvae and 4 d old postlarvae was tested in small-scale static bioassays with different bacterial concentrations (10(2) to 10(6) cells ml(-1)). Larval and postlarval survival were evaluated at 24 and 48 h. Results suggest that V. alginolyticus can cause massive mortality in lar...

In general, the surfaces of any solid immersed in water are covered by boundary layers that are minimally affected by water motion in the system, and in which dissolved molecules are transported mainly by diffusion. Microgradients of environmental conditions within diffusive boundary layers on the surfaces on which abalone (Haliotis spp.) postlarva...

Statistical power is the probability of not committing a Type II error (i.e. accepting a false null hypothesis) when inferences are made from the analysis of experimental data. The consideration of power is particularly important for the interpretation of non-significant results and for the design of meaningful experiments. Nevertheless, it is gene...

The sampled age range was 5-43 yr and the length range was 9.5-15.9 cm. The Ford-Walford method was applied to calculate the parameters of the model using three types of regression: predictive, Bartlett and functional (geometric mean). The last approach resulted in a better fit to the data observed in the catch samples; however, apparently none of...

This contribution describes two experiments that compare three methods of abalone metamorphosis induction: diatom-film, mucus and gamma-aminobutyric acid (GABA), under commercial-scale conditions. GABA was consistently the most efficient method (72–76% induction after 24 h) while the diatom-film treatment was the least effective (8–12% induction af...

Age was determined in 1,368 pismo clams (Tivela stultorum, Mawe, 1823) by growth ring analysis, in commercial catch samples collected from July 1978 to February 1983. Approximately 25 age classes were present between 1978 and 1980, divided into two modal groups (younger and older than 21 years), suggesting the occurrence of wide fluctuations in abu...

SEARCY BERNAL, R., 1983. Un estudio sobre Ia condición de la almeja Pismo tivela stultonrm con datos de longitud y peso de la carne de capturas comerciales. Ciencias Marinas, 9 (2): 19-30. RESUMEN Se desarrolla un índice para medir la condición en bivalvos, basado en datos de longitud de la concha y peso de la carne, aplicándose para la almeja pism...

This contribution examines the possibility of titting the von Bertalanffy growth model, using age-length matrices from the analysis of shells of commercial catch samples of the pismo clam, Tivela stultorum, from Playa San Ramón, B.C., Mexico. The sampled age range was 5 to 43 years and the length range was 9.5 to 15.9 cm. The Ford-Walford method wa...

Thesis (Ph. D.)--University of California, Davis and San Diego State University, 1999. Includes bibliographical references (leaves 64-68).