El desarrollo larvario de Sabellastarte spectabilis (Grube, 1878) (Polychaeta: Sabellidae) en Hawaii

The sabellid polychaete Sabellastarte spectabilis is common in bays and harbours throughout Hawaii. It has become one of the most harvested marine ornamental species in the State. Collection can be difficult and potentially damaging to the reef community. Understanding the reproduction and life history of this polychaete will benefit the marine ornamental trade by facilitating aquaculture of the species and coral reef conservation by decreasing destructive collecting practices. There is very little known about the biology of this species. Experiments were conducted at the Hawaii Institute of Marine Biology to induce and document spawning and larval development. Oocytes range between 150-200 µm in diameter and sperm have spherical heads. Cell division in fertilized eggs begins approximately twenty minutes after spawning. Developmental stages were documented using light and scanning electron microscopy. Swimming larvae are first seen 7-8 h after spawning. Larvae have a well-developed prototroch and a less conspicuous neurotroch and metatroch. Two chaetigers develop sequentially on days 4 and 5 and settlement occurs 6-7 days after spawning. Metamorphosis occurs gradually from days 6-8. This is the first reported induction of spawning and description of larval development from fertilized egg to settlement and metamorphosis for this species.El poliqueto sabélido Sabellastarte spectabilis es común en bahías y puertos de Hawaii. Este sabélido ha llegado a ser una de las especies ornamentales marinas más recolectadas en el estado, pero su recolección es difícil y en muchos casos ocasiona daño a la comunidad arrecifal. Pese a ello, el conocimiento sobre su biología es escaso. El estudio de la reproducción y ciclo de vida de estos sabélidos facilitará su cultivo y beneficiará al mercado de especies ornamentales, a la vez que la diminución de la recogida destructiva se espera pueda contribuir a la conservación de los arrecifes coralinos. En el Hawaii Institute of Marine Biology se realizaron algunos experimentos con la finalidad de inducir y documentar su reproducción y desarrollo larvario. Los huevos miden entre 150-200 μm de diámetro y los espermatozoos presentan cabezas redondas. La división celular de huevos fertilizados comienza aproximadamente 20 minutos después del desove. Los estadios larvarios se documentaron con microscopios de luz y microscopia electrónico de barrido. Las primeras larvas aparecen 7-8 horas después del desove. Las larvas tienen una prototroca muy bien desarrollada y una neurotroca y metatroca menos conspicua. Entre los días 4 y 5 se desarrollan dos setígeros y el reclutamiento ocurrió 6-7 días después del desove. La metamorfosis ocurre gradualmente entre los días 6-8. Este estudio describe por primera vez la inducción del desove y la descripción del desarrollo larvario desde la fertilización del huevo hasta el establecimiento y metamorfosis de la especie. &nbsp

A Preliminary Study of Microbial Water Quality Related to Food Safety in Recirculating Aquaponic Fish and Vegetable Production Systems

This study examines microbial water quality in recirculating aquaponic systems. The pathogens studied were E. coli and Salmonella, and the levels were compared with existing food safety standards

Speciation and Evolution of Marine Fishes Studied by the Electrophoretic Analysis of Proteins

Electrophoretic analysis of proteins can be utilized to clarify the taxonomic status of species as well as the evolutionary interrelationships of populations, species, and higher taxa. Electrophoretic data for over 50 gene loci in the bonefish Albula "vulpes" (Albulidae) demonstrate the existence of two discrete species in Hawaii and throughout the Indo-West Pacific. Similar studies of lizardfishes (Synodontidae) in the genera Synodus and Saurida reveal that several unreported and/or undescribed species occur in the Hawaiian Islands. Both of these studies emphasize the power of electrophoresis in distinguishing morphologically cryptic species. The interrelationships of species and genera of lizardfishes and of goatfishes (Mullidae) were investigated by using values of genetic distance derived from protein similarities and differences. These comparisons and the analysis of the two bonefish species, provide additional examples of the basic independence of the rates of biochemical and morphological evolution. Published electrophoretic investigations of fish speciation and evolution are reviewed and several guidelines for future applications of the technique are proposed. The importance of sympatric samples, the use of large numbers of gene loci, and the conservative interpretation of genetic distance values are emphasized. The utility of electrophoretic data for (a) identifying species (especially juvenile, larval, and embryonic stages, or isolated animal products such as fillets); (b) identifying F 1 interspecific hybrids; and (c) estimating absolute and relative divergence times between taxa are discussed. Finally, the combined use of electrophoretic data from fresh specimens together with multivariate morphometric analyses of both the fresh specimens and preserved museum type specimens is recommended as a robust approach for sorting out nomenclatural problems

Evidence for Sequential Hermaphroditism in Sabellastarte spectabilis (Polychaeta: Sabellidae) in Hawai‘i.

v. ill. 23 cm.QuarterlyUnderstanding the reproductive characteristics of Sabellastarte spectabilis (Grube, 1878), an economically important polychaete worm collected forthe aquarium trade, is essential to the development of artificial propagation and conservation of coral reefs. The purpose of this study was to determine whether S. spectabilis is hermaphroditic. Using histological techniques, 180 individuals were examined for gametes. Gametes were present only in abdominal segments. Primary oocytes were 7–8 mm in diameter in histologically prepared sections. Sperm appeared as round black dots about 2 mm in diameter on histologically prepared slides. Most individuals sampled had only one type of gamete in the coelom, but both eggs and sperm were seen in the coelom of 15% of individuals, demonstrating the occurrence of hermaphroditism in Hawaiian populations of S. spectabilis. The sex ratio of males to females was skewed significantly toward males in both the small (6–8 mm diameter) and medium (9–10 mm diameter) sized worms. Among the largest worms (11–13 mm diameter), the sex ratio did not diverge significantly from 1: 1. There was a significantly higher proportion of hermaphrodites (30%) in the large size class. Worms of unknown gender, although present in all size classes examined, were most frequent (33%) in the medium size class. Thes

Induced maturation and spawning of milkfish, Chanos chanos Forsskal, by hormone implantation

This research work was supported by a grant from USAID (DAN-4161-A-00-4055-00).The milkfish, Chanos chanos Forsskal, does not reach gonadal maturity easily in captivity. In an attempt to induce maturation, exogenous hormones, LHRH-A and 17α-methyl-testosterone, were implanted into adult milkfish either alone or in combination. The hormones were delivered using cholesterol pellets (LHRH-A) or silastic tubing sealed with elastomer (17α-methyl-testosterone). The fish were implanted three times at monthly intervals between March and May of 1985. The combination of LHRH-A and 17α-methyl-testosterone induced significantly more maturing fish (P < 0.05) than LHRH-A alone or sham controls; 88%, 38%, and 13%, respectively. Fish with average egg diameters between 768 μm and 905 μm, spawned 48 h after hormone implantation. These results indicate that the maturation and spawning of milkfish in tanks can be induced and accelerated 1–2 months earlier than the beginning of the normal spawning season through hormone implantation