The database on neurotransmitter distribution during central nervous system development of cephalopod mollusks is still scarce. We describe the ontogeny of serotonergic (5‐HT‐ir) and FMRFamide‐like immunoreactive (Fa‐lir) neurons in the central nervous system of the benthic Octopus vulgaris and Fa‐lir distribution in the pelagic Argonauta hians. Comparing our data to previous studies, we aim at revealing shared immunochemical domains among coleoid cephalopods, i.e., all cephalopods except nautiluses. During development of O. vulgaris, 5‐HT‐ir and Fa‐lir elements occur relatively late, namely during stage XII, when the brain neuropils are already highly differentiated. In stage XII‐XX individuals, Fa‐lir cell somata are located in the middle and posterior subesophageal mass and in the optic, posterior basal, and superior buccal lobes. 5‐HT is predominately expressed in cell somata of the superior buccal, anterior basal, and optic lobes, as well as in the subesophageal mass. The overall population of Fa‐lir neurons is larger than the one expressing 5‐HT. Fa‐lir elements are distributed throughout homologous brain areas of A. hians and O. vulgaris. We identified neuronal subsets with similar cell number and immunochemical phenotype in coleoids. These are located in corresponding brain regions of developmental stages and adults of O. vulgaris, A. hians, and the decapod squid Idiosepius notoides. O. vulgaris and I. notoides exhibit numerous 5‐HT‐ir cell somata in the superior buccal lobes but none or very few in the inferior buccal lobes. The latter have previously been homologized to the gastropod buccal ganglia, which also lack 5‐HT‐ir cell somata in euthyneuran gastropods. Among coleoids, 5‐HT‐ir neuronal subsets, which are located ventrally to the lateral anterior basal lobes and in the anterior middle subesophageal mass, are candidates for homologous subsets. Contrary to I. notoides, octopods exhibit Fa‐lir cell somata ventrally to the brachial lobes and 5‐HT‐ir cell somata close to the stellate ganglia. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
The catch composition and economic impacts of ghost fishing in the fishing grounds near Suan Son Beach, Rayong province, Thailand, were examined based on interviews of squid fishers and experiments using ghost-fishing squid traps. In the province, 27 fisher families are engaged in squid trap fishing, and each family operates 100-300 squid traps. The catch per unit effort (CPUE) of the traps is 30-40 kg/100 traps/trip. The average price of a squid trap is 135 Thai baht (US$ 4.50), and traps have a lifespan of 1-2 months. Squid traps can ghost fish when they are lost in bad weather conditions, due to gear conflict, or when the trap materials deteriorate. The catches of experimental ghost-fishing traps were examined during two periods in 2017: May-July and August-October. The traps caught cephalopods and other species, both commercial and non-commercial. The commercial species included bigfin reef squid (Sepioteuthis lessoniana), other squids, cuttlefishes, groupers, snappers, and blue swimming crabs. The total number of aquatic animals, total weight, and total economic value of the catches during May-July and August-October 2017 were 51 and 38 specimens; 12 000 g and 7250 g; and 6318.0 baht/27 traps and 5302.5 baht/28 traps, respectively.
The embryonic development, morphology of the eggs, and newly hatched paralarvae of the sandbird octopuses (Amphioctopus aegina) were described using laboratory-reared specimens. Mature octopuses were collected from an artisanal fishery at Baan Salakeaw, Baan Phe District, Rayong Province, Thailand. The spawned eggs were examined. The non-adhesive eggs were attached to a string to form a cluster, and the average egg size was 2.64 ± 0.13 mm in length and 0.94 ± 0.06 mm in width. Females brooded the eggs in their arms until hatching. The embryonic development period was divided into 27 stages. The first embryo inversion occurred at stage 11, and primordia of major body parts, such as the arms, head, and mantle, also appeared. Eyespots appeared at stage 12, chromatophores appeared on the ventral side at stage 18 and on the dorsal side at stage 19, and the external yolk sac decreased in size until it disappeared at stage 27 (hatching stage). The paralarvae hatched after 18-22 days at 28.0 °C and swam to the surface. The average total length of paralarvae was 3.40 ± 0.24 mm. The paralarvae had a stubby oval shape mantle. Their arms were subequal in length with 5 suckers arranged in a single row per arm, and the eyes became conspicuous. The dorsal side of the head had 2-3 rows of large reddish brown chromatophores with 4 chromatophores in each row. On the funnel, there were 5 chromatophores in two rows each with three and two chromatophores. A single row of chromatophores occurred on the ventral mantle margin.
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