Ciclo vital del pulpo marmóreo, Amphioctopus aegina (Gray) (Cephalopoda: Octopodidae) criado en laboratorio

Reproducing small eggs and planktonic hatchlings is a reproductive strategy of many species of benthic octopods although it is considered a pleisiomorphic state. The young in the planktonic and settling phases have a high energy consumption and require live food of specific size range characteristics, causing difficulties in obtaining appropriate food organisms for rearing experiments through the entire life cycle. This study obtained information on details of life cycle characteristics of Amphioctopus aegina (Gray) by resolving these difficulties. The aspects of life cycle of A. aegina were similar to those of other benthic octopus with a similar reproductive strategy. Growth was allometric, consisting of 3 phases in terms of body weight, including a transitional phase for the early settling stage. Feeding and conversion efficiency peaked over a 2-month period prior to reproduction, representing the period of energy storage. Growth from hatching to spawning took approximately 74% of the entire life span and the reproductive phase itself took 34%. Such longevities are similar to those of other benthic cephalopods with planktonic hatchlings. Overall similarities in these cephalopod taxa attest to the fitness of a life-history strategy involving production of planktonic offspring from benthic adults. A. aegina is the second benthic octopus species with planktonic hatchlings for which the life cycle has been completed through rearing in the laboratory.El desove de pequeños huevos que darán origen a plancton constituye la estrategia de reproducción de numerosos octópodos bénticos, aunque se asocia a un estado plesiomórfico. Las nuevas criaturas en fase planctónica y de asentamiento requieren un gran consumo energético y nutrientes vivos con características y dimensiones específicas, lo que dificulta la obtención de organismos que les sirvan de alimento a lo largo de todo el ciclo vital. A partir de este estudio se han obtenido datos sobre las características del ciclo vital del Amphioctopus aegina (Gray) mediante la resolución de estas dificultades. Muchos aspectos del ciclo vital del A. aegina resultaron muy similares a los de otros pulpos bénticos con una estrategia de reproducción parecida. Se produjo un crecimiento alométrico en tres fases, según el peso corporal, que incluía una fase de transición en el periodo de asentamiento inicial. La eficacia en la alimentación y la conversión alcanzó su punto máximo en los 2 meses previos a la reproducción, que representan un periodo de almacenamiento energético. El crecimiento desde la eclosión hasta el desove fue aproximadamente el 74% del ciclo vital completo, y la fase reproductiva en sí supuso un 34%. Tal longevidad es compartida por otros cefalópodos bénticos con desoves planctónicos. Las similitudes generales entre estas categorías taxonómicas de cefalópodos confirman el éxito de esta estrategia de ciclos vitales en la producción de crías planctónicas por parte de adultos bénticos. A. aegina es la segunda especie de pulpo béntico con desove planctónico cuyo ciclo vital ha logrado completarse mediante la cría en laboratorio

Phylogenetic Relationships of the Flying Lizards, Genus Draco (Reptilia, Agamidae)

Phylogenetic relationships among 12 species of the genus Draco were inferred from 779 base pairs of mitochondrial 12S and 16S rRNA genes and allozymes for 20 presumptive loci. Results indicated the presence of at least four distinct lineages within the genus. The first lineage consists of D. volans and D. cornutus, whereas the second only of D. lineatus, which exhibits a great genetic divergence between two subspecies. The third is monotypic with D. dussumieri, the only species distributed in southern India. The fourth included all the remaining species. The third and fourth lineages are supposed to exclusively share a common ancestor. It is likely that the common ancestor of whole Draco originally diverged into three groups, the ancestors of the first, second, and third and fourth lineages, by vicariance. In the fourth lineage, D. blanfordii, D. haematopogon, D. melanopogon, D. obscurus and D. taeniopterus are likely to be exclusively close to each other. The resultant phylogenetic tree contradicts the dichotomous relationships previously hypothesized on the basis of morphological characters

Evolution of Asian and African Lygosomine Skinks of the Mabuya Group (Reptilia: Scincidae): A Molecular Perspective

Phylogenetic relationships among Asian and African lygosomine skinks of the Mabuya group were inferred from 825 base pairs of DNA sequences of mitochondrial 12S and 16S rRNA genes. Results indicated the presence of two distinct lineages within this group, of which one consisted of Lamprolepis and Lygosoma, and the other of Apterygodon, Dasia, and Asian and African Mabuya. Within the latter, African species of Mabuya first diverged from the remainder, leaving the Asian congeners together with the Apterygodon-Dasia clade. Our results, while suggesting the non-monophyly of the genus Mabuya, do not support the currently prevailing phylogeographical hypothesis which assumes the independent origins of Lamprolepis and Lygosoma from the Asian Mabuya-like stock. On the other hand, our results suggest that morphological and karyological similarities between the Apterygodon-Dasia clade and Lamprolepis are attributable to symplesiomorphy, while their ecological similarity to convergence. Morphological and karyological character states unique to Apterygodon are supposed to have evolved from those exhibited by Dasia

Fisheries Co-management: An Experiential Account from Phang Nga Bay, Thailand

Like most other coastal water bodies around the world, this Thailand’s largest bay on the Andaman seaboard has suffered the similar plights that have led to serious deterioration of coastal resources over the years. Despite its natural wealth derived from the fertile watershed and tropical climatic settings, Thailand’s modern economic policies, began in 1960, have partly contributed to heavy exploitation, sometimes with destructive and indiscriminate fishing gears, resulting in a rapid decline in fish and invertebrate standing crops. Under the control of State, all fishing grounds are subject to legal measures issued primarily under the 1947 Fishery Act where fishery patrol workforce has confronted the persistent illegal fishers who have taken control by their sheer number. The government has also implemented the resource restoration measures, e.g. artificial reef placement, closed season, and closed area. The impacts on marine fisheries of marine shrimp farming that has occupied the increasing acreage along the fertile shoreline have been noted, as it closely links to other aquacultural practices, particularly those in and around the Bay. Attempting to take control in this difficult game of number, Thailand adopted community-based fishery management in the 1960s with a design for people to control people. The 1947 Constitution has helped accelerated the administrative devolution and much of the centrally controlled measures have since 2003 come under the provincial administration, headed by the more powerful governor CEO. The speedier countermeasures against illegal fishing, by local communities and governor CEO, have proved to be effective, and Phang Nga Bay in the past two years can be said to recover—almost disappearance of destructive fishing, and reappearance of some fish species, e.g. Hilsa, certain dolphins, and dugong. All these have paved a solid foundation for further co-management where all key stakeholders share decision-making and implementing their plans toward achieving their common goals. The 5-year Coastal Habitats and Coastal Resources Management (CHARM) project, co-funded by Royal Thai Government and the European Union has been devising and implementing this concept since November 2002, fortunately with some promising results. Andaman Triangle Network, a recently established coastal resource conservation group comprising relevant government departments, NGOs, and community leaders, has been active in the three provinces bordering Phang Nga Bay. What the ATN has been advocating is the co-management approach, which is intended to replace the centrally management regime, the failure of which has been evidenced by the widespread deterioration of coastal resources

World squid fisheries

Peer reviewedPublisher PD

Sperm transfer or spermatangia removal: postcopulatory behaviour of picking up spermatangium by female Japanese pygmy squid

In the Japanese pygmy squid Idiosepius paradoxus, females often pick up the spermatangium using their mouth (buccal mass) after copulation. To examine whether the female I. paradoxus directly transfers sperm into the seminal receptacle via this picking behaviour, or removes the spermatangium, we conducted detailed observations of picking behaviour in both virgin and copulated females and compared the sperm storage conditions in the seminal receptacle between females with and without spermatangia picking after copulation in virgin females. In all observations, elongation of the buccal mass occurred within 5 min after copulation. However, sperm volume in the seminal receptacle was not related to spermatangia picking. Observations using slow-motion video revealed that females removed the spermatangia by blowing or eating after picking. These results suggest that picking behaviour is used for sperm removal but not for sperm transfer. Moreover, the frequency of buccal mass elongation was higher in copulated females than in virgin females, consistent with the sequential mate choice theory whereby virgin females secure sperm for fertilisation, while previously copulated females are more selective about their mate. Female I. paradoxus may choose its mate cryptically through postcopulatory picking behaviour

Spermatangium formation and sperm discharge in the Japanese pygmy squid Idiosepius paradoxus

In cephalopods, sperm discharge is an important event not only for sperm transfer but also influencing sperm storage capacity of attached spermatangia (everted spermatophores). To investigate sperm discharge from spermatangia and the condition of naturally attached spermatangia in Japanese pygmy squid (Idiosepius paradoxus) we (i) investigated the morphology of spermatophores and spermatangia, and the process of spermatophore evagination and sperm discharge from spermatangia obtained in vitro; (ii) observed spermatangia that were naturally attached to female squids at 6, 12, 18, 24 and 48. h after copulation to investigate alterations in naturally attached spermatangia with time. The spermatophore of I. paradoxus is slender and cylindrical and consists of a sperm mass, a cement body and an ejaculatory apparatus, which is similar to those of loliginid squids. The spermatangium is fishhook-shaped, its distal end being open and narrow. After the spermatangium is formed, the sperm mass gradually moves to the open end of the spermatangium, from where sperm are released. Sperm discharge is a rapid process immediately after the beginning of sperm release, but within 5. min changes to an intermittent release of sperm. Although the volume of residual spermatozoa differed among spermatangia that were naturally attached to a single individual, the probability that spermatangia would be empty increased with time. Most naturally attached spermatangia discharged almost all of their spermatozoa within 24. h after copulation, and no spermatangia were attached to females 48. h after copulation. These results suggest that sperm transfer from the spermatangium to the seminal receptacle must occur within 24. h, and that the spermatangium functions as a transient sperm storage organ in pygmy squids

The Current State of Cephalopod Science and Perspectives on the Most Critical Challenges Ahead From Three Early-Career Researchers

International audienceHere, three researchers who have recently embarked on careers in cephalopod biology discuss the current state of the field and offer their hopes for the future. Seven major topics are explored genetics, aquaculture, climate change, welfare, behavior, cognition, and neurobiology. Recent developments in each of these fields are reviewed and the potential of emerging technologies to address specific gaps in knowledge about cephalopods are discussed. Throughout, the authors highlight specific challenges that merit particular focus in the near-term. This review and prospectus is also intended to suggest some concrete near-term goals to cephalopod researchers and inspire those working outside the field to consider the revelatory potential of these remarkable creatures

Mass Culture of Cephalopods in Thailand

Cephalopod research in Thailand has been underway since 1978 with the goal of developing successful mass-culture techniques. Results of mass cultivation have demonstrated several favorable aquaculture characteristics of cephalopods, i.e., high growth rates, short life cycle, high fecundity, high hatching rate, and absence of true larval stages. Three species are being cultured: bigfin squid, Sepioteuthis lessoniana; spineless cuttlefish, Sepiella inermis; and pharaoh cuttlefish, Sepia pharaonis. They were listed in declining order of production and suitability for aquaculture. About 2 million cephalopod seed have been produced and released annually since 1990 to enhance natural stock. Biohistory, behavior and water quality requirements are also being studied in order to supply basic information for aquaculture. However, there are also several obstacles, particularly development of cost-effective feeds