A restocking experiment was conducted to determine the influence of release density on growth, survival with protection (natural), and survival without protection (by predation) in the winged pearl ...oyster Pteria sterna. Adult oysters were directly placed over the sea floor at 10 m depth in triplicate, 3 × 3 m parcels at densities of 5, 10 and 15 oysters m−2. Individual protection structures elaborated with dark, 31 mm plastic mesh were placed over each parcel. At the end of month 8, the structures were removed and the oysters were left unprotected thereafter to further assess mortality by predation. Oysters released at high density experienced a significantly greater increase in DVM and lower predation than oysters released at low density. Improved survival in oysters released at high density was likely influenced by the protection offered by the aggregation of individuals in dense clusters, compared to oysters stocked at low densities that did not form aggregations, or these were small. Oysters at all densities remained established at the restocking site and were likely to contribute at least once as breeders during the study to larval and juvenile recruitment back to the population.
•Oysters released at high density grew faster and showed higher natural survival while protected.•Protection of oysters is key to ensure survival after release.•Oysters released at high density showed lower predation after protection was removed.
One of the main problems in laboratories of oyster seed production occurs in the stage of settlement or fixation and metamorphosis of the larvae. The organisms develop drastic morphological and ...physiological changes at this stage, exposing them to attack by pathogenic microorganisms. Numerous studies indicate that before larval settlement to a substrate, they require bacteria to stimulate and induce the process. In this study, Japanese oyster (Crassostrea gigas) larvae were fed with combinations of microalgae and bacteria previously selected for their probiotic potential; their impact on survival, growth, and settlement was evaluated. Larvae D of 12 days old were provided by a private company and transported to the laboratory under controlled conditions. Probiotic bacteria Lactobacillus plantarum 69Cr, L. fermentum 101Cc, and L. casei 43Cg were reactivated on MRS and applied at a concentration of 1 X 10.sup.4 CFU mL.sup.-1. Microalgae Isochrysis galbana and Chaetoceros calcitrans were grown in F2 medium and supplied at a concentration of 3 X 10.sup.4 cells mL.sup.-1. Results showed, in all treatments, a survival range of 39-53%, growth of 300-310 microm, and 34-56.5% settlement. However, the best bacteria combined with I. galbana and C. calcitrans was L. plantarum 69Cr with a 54% survival, 310 microm growth, and 56.5% settlement. It is concluded that the combination of L. plantarum 69Cr with I. galbana and C. calcitrans has the potential to be used in the production of Japanese oyster larvae.
In this study, five microalgal strains were isolated from Bahía de La Paz, Baja California Sur, Mexico and identified as Grammatophora sp., Navícula sp., Rhabdonema sp., Schizochytrium sp., and ...Nitzschia sp., and their evaluation as potential food for Artemia franciscana. The isolated strains were cultured outdoors and harvested after four days. Chaetoceros muelleri was cultured under laboratory conditions and used as control. The protein, lipid, and carbohydrate composition and the fatty acid profiles of the strains were determined by gas chromatography. To assess the effect of microalgal strains on A. franciscana, decapsulated cysts were cultured at outdoor conditions in 15 L containers. The experiment was conducted for twelve days. Samples from the five different feeding treatments were taken at the beginning and end of the experiment to assess number, size, and weight of Artemia larvae. Treatment with Rhabdonema sp. showed larvae with a lower percentage of polyunsaturated fatty acids (PUFAs) while Grammatophora sp. showed those with the greatest PUFA proportion, even more than those fed Chaetoceros muelleri (control). Larvae consuming Schizochytrium sp. had no docosahexanoic (DHA) nor eicosapentaenoic (EPA) fatty acid content. Growth and survival of A. franciscana did not show significant differences among feed treatments, except when it was fed Nitzschia sp., showing lower survival and dry weight. Treatment based on Schizochytrium sp. and Rhabdonema sp. had a greater A. franciscana size but reduced dry weight; additional tests including two or more algal species for every treatment should be carried out to determine the best yield.
Abstract
The biology of the scleractinian
Porites sverdrupi
, endemic to the Gulf of California, is poorly studied. In order to fill that gap, the present study documents the reproductive biology of ...this coral which is to date protected by the IUCN’s as “vulnerable” and listed as “in risk of extinction” in the Mexican Federal Law for species protection. Also, potential distribution models were constructed to evaluate the status of the remaining species’ populations, and the role that reproduction has in their permanence
. Porites sverdrupi
show a gonochoric brooding reproductive pattern, with asynchronous gamete development regulated by sea surface temperature and light. The potential distribution models suggest that this coral currently covers less than 6% of its original range of distribution. Furthermore, the results suggest that, despite the drastic decline of the species, the remaining populations have the ability to persist even under current changing ocean conditions as successful sexual reproduction was documented even during the strong 2014–2015 ENSO event producing sexual recruits to maintain themselves.
Ten species of microalgae were tested for ingestion and digestion in
Pteria sterna larvae using epifluorescence microscopy to choose an appropriate diet. An experiment was conducted using 2, 4, 5 ...(straight-hinge) 10 and 22 (umbo stage) day old larvae. Larvae were stocked in 150
ml flasks at 30
ml
–1 and fed 100,000 algal cells
ml
−1 of each species individually. Larvae were fed for 1
h and then were observed under the microscope to detect ingestion; larvae were then sieved and placed in flasks containing filtered seawater and were observed after 1 and 2
h to analyse digestion for the microalgae ingested. Out of the 10 species administered, only
Nannochloris sp.,
Pavlova lutheri and
Isochrysis aff.
galbana (T-ISO) were ingested, and only the last two species were digested. No ingestion of
Phaeodactylum tricornutum, Chaetoceros muelleri, Ch. calcitrans, Thalassiosira weisflogii, Dunaliella salina, Tetraselmis tetrathele and
T. suecica was evident at any stage of larval development tested. Only T-ISO and
P. lutheri should be used for larval rearing of
P. sterna until other species are identified as suitable (ingested and digested) for this species.
Relaxation and excision of mantle tissue from live lions-paw scallops can assist in the optimum development of pre-operative techniques for pearl production in this species. To determine the ...feasibility of relaxing the scallop, five scallops were exposed to each of nine relaxant treatments previously used for pearl seeding operations. Relaxation and suitable conditions for seeding operations were obtained in scallops exposed to 30gL−1 magnesium chloride and to 1mLL−1 2-phenoxyethanol. To determine the healing capacity and ability to sustain tissue excision, a section of mantle tissue was removed from 15 relaxed scallops. Survival 30days after excision was 87% and all scallops showed signs of regeneration. Microscopic examination confirmed the elongation of the mantle epithelia and growth of new connective tissue. This relaxation technique is an important step in developing basic technology for pearl production, as previously accomplished with other species. This is an important tool that will improve successful production of lions-paw scallop cultured pearls. This can add significant value to the scallop-cultivating industry and the pearl industry.
► Scallops can be relaxed in 20–40 min using magnesium chloride or 2-phenoxyethanol. ► Scallops are able to survive excision of a section of mantle tissue. ► Scallops showed very high survival rates. ► This tool will improve the potential for successful production of cultured pearls.
Two groups of 96 winged pearl oysters,
Pteria sterna, with mean (±
S.D.) dorso-ventral shell height (DVM) of 75.0
±
6.0 mm, were used to evaluate the effect of two culture methods (pocket nets and ...plastic cages) on the quality of half-pearls (mabé) produced from them over a period of 9 months. Prior to implantation, oysters were anaesthetized using benzocaine and two plastic nuclei were implanted on the left valve and one on the right valve of each pearl oyster. Oysters were returned to culture conditions and were sampled to determine nacre secretion and pearl quality 5, 7, 9 and 11 months after nucleus implantation. There was no significant difference (
P
>
0.05) between growth rates of oysters cultured in plastic cages and those held in pocket nets. However, a greater yield of commercial quality pearls was produced by oysters grown in plastic cages. Nacre thickness at the top of the resulting half-pearl blisters showed no significant difference between oysters held in the different culture apparatus (
P
>
0.05) or between different months (
P
>
0.05). Highest mabé quality was recorded 9 months after nucleus implantation when water temperatures were low. Growth of pearl oysters during this study resulted in enlargement of adductor muscle, which in some cases grew to cover the mabé. This result indicates that
P. sterna with a dorso-ventral shell height greater than 75 mm should be used for the production of mabé. Furthermore, the results suggest that a culture period of 9 months is required to optimize the quality of mabé produced from
P. sterna cultured in plastic cages.
Pediococcus pentosaceus strain PP16CC comes from the intestine of Crassostrea corteziensis. A 1.82-Mbp draft genome of this strain was assembled using A5-miseq from illumina reads, resulting in 4 ...contigs and 1,856 predicted protein coding genes. Additionally, 23 proteins belonging to various glycosyl hydrolase families and 6 prophage regions were identified.
Las macroalgas marinas son un método de control biológico que disminuyen el daño que provoca el nematodo agallador en los cultivos de importancia económica. El presente estudio tuvo como objetivo ...evaluar el efecto de cuatro macroalgas en el control de Meloidogyne incognita y su efecto bioestimulante en albahaca. Para ello, cuatro extractos derivados de Ulva lactuca, Ulva clathrata, Gracilaria spp. y Sargassum spp. fueron evaluados en tres dosis (1 000, 2 000 y 3 000 ppm) sobre la eclosión de huevecillos y su eficacia en la germinación, longitud de tallo y raíz de plántulas. Se realizó un análisis fitoquimico de las macroalgas que presentaron acción nematicida sobre los huvecillos. Los resultados mostraron que el extracto de Sargassum spp. y U. lactuca bajo las dosis evaluadas generaron el menor número de huevecillos eclosionados. Pero, ninguna macroalga incrementó elporcentaje de germinación, pero si la longitud de tallo. El análisis fitoquímico del extracto de Sargassum spp. registró el mayor contenido de alcaloides, fenoles, fitoesteroles, péptidos y saponinas. Se comprueba la eficacia de algunas macroalgas marinas sobre el control de M. incognita y su acción bioestimulante en la planta, lo cual es de gran interés para la agricultura orgánica y convencional.
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