Canthigaster Rostrata Research Articles

Histological Observations of the Sharpnose Pufferfish, Canthigaster rostrata (Bloch, 1786), Collected Along the Caribbean Coast Affected by Mass Mortality Episodes

Histological Observations of the Sharpnose Pufferfish, Canthigaster rostrata (Bloch, 1786), Collected Along the Caribbean Coast Affected by Mass Mortality Episodes

Caribbean Sharp-nosed Pufferfish (Tetraodontidae: Canthigaster rostrata) Tetrodotoxin Poisoning in Two Dogs in Honduras

We report the details of a case of toxicosis in two four-month-old mixed breed dogs by the Caribbean Sharp-nosed Pufferfish, Canthigaster rostrata, a small but lethally neurotoxic marine fish that contains tetrodotoxin (TTX) as well as potential saxitoxins (SSXs). Following consumption of at least 30 juvenile C. rostrata individuals, one dog showed gastrointestinal and neurological symptoms indicative of presumptive TTX poisoning that endured for four to six hours. The dog recovered within six to 12 hours following treatment with activated charcoal. The second dog consumed five to ten juvenile C. rostrata individuals and exhibited no major side-effects. To our knowledge, this is the first report of dogs poisoned by C. rostrata, which contributes to the present understanding of tetrodotoxin toxicosis and treatment in canines. We document this case to bring awareness of this potential risk to pet-owners and veterinarians working in coastal Neotropical areas.

NOTAS SOBRE LA REPRODUCCIÓN, MORFOLOGÍA Y ECOLOGÍA DE Pareques acuminatus (TELEOSTEI: SCIAENIDAE), EN LA REGIÓN DE SANTA MARTA, CARIBE COLOMBIANO.

Pareques acuminatus (familia Sciaenidae) es una especie carnívora de tamaño pequeño, que se distribuye en el Atlántico occidental: Carolina del Norte y Bermudas hasta Brasil. Los estudios sobre la biología y ecología de P. acuminatus son escasos y en Colombia no se han realizados trabajos concernientes a la especie. El propósito de este estudio fue conocer la biología de la especie y determinar aspectos ecológicos con el fin de ampliar su conocimiento en el Caribe colombiano. Se hicieron capturas de la especie por medio de buceo libre y se realizaron censos visuales del hábitat donde fue observada. La morfometría y merística fue evaluada, se identificaron las fases reproductivas y se estimó la fecundidad parcial mediante el método gravimétrico. Un total de 85 individuos fueron recolectados con una LT entre 33 y 185 mm (123,7±36,3 mm) siendo más frecuentes aquellos entre 121-142 mm (42%) seguidos de los de 143-164 mm (20%). Se distinguieron 39 hembras, 34 machos y 12 fueron indeterminados debido a su pequeño tamaño. La talla de las hembras maduras fue a partir de una LT de 118 mm, siendo una especie asincrónica con dos fases reproductivas (en desarrollo y capaz de desove). La fecundidad parcial estimada fue de 8744 ± 3900 oocitos y la fecundidad relativa con relación a la talla fue de 64,15 ± 25,51 oocitos/mm con un diámetro de 0,53 ± 0,04 mm. Pareques acuminatus es una especie típica de hábitats arrecifales someros y se encontró acompañada principalmente de Myripristis jacobus, Canthigaster rostrata, Haemulon steindachneri, H. flavolineatum, Stegastes partitus y Chromis multilineata.

Saxitoxin Poisoning in Green Turtles (Chelonia mydas) Linked to Scavenging on Mass Mortality of Caribbean Sharpnose Puffer Fish (Canthigaster rostrata-Tetraodontidae).

Fish within the family Tetraodontidae are potential sources of both endogenous tetrodotoxins (TTXs) and dietary derived saxitoxins (STXs). Ingestion of fish tissues containing these toxins by other vertebrates can lead to severe illness and death. The Caribbean sharpnose puffer (Canthigaster rostrata) is a widespread tetraodontid species within the western Atlantic. Mass settlement of juveniles into foraging habitats have been associated with large-scale puffer fish mortality events. In 2013, 2014, and 2017, puffer mortality events on the southern Caribbean coast of Costa Rica were also associated with strandings of green turtles (Chelonia mydas) found to have fed on C. rostrata. Stranded sea turtles were found dead without apparent cause or alive with severe neurological signs that resolved during short periods of captivity. Puffer fish and turtle organ samples were analyzed for both TTXs and STXs. Concentrations of TTXs were extremely low in the fish (0.5–0.7 μg/g) and undetectable in turtle stomach contents. However, concentrations of STXs in whole fish (16.6–47.5 μg STX-eq/g) exceeded the 0.8 μg STX-eq/g human seafood safety threshold for STXs by orders of magnitude. Saxitoxins were also detected in samples of stomach contents (ingested fish), brain, lung, kidney, and serum from three affected turtles. Study results indicate that saxitoxicosis resulting from opportunistic foraging on C. rostrata during fish mortality events may be a significant factor in episodic stranding of green sea turtles in this region.

What are the characteristics of lionfish and other fishes that influence their association in diurnal refuges?

ABSTRACTIn Caribbean reefs, the lionfish Pterois volitans is an invasive species that causes severe negative ecological effects, especially as this crepuscular predator consumes very diverse prey. Lionfish are not active during the day and stay in their refuges, sharing these spaces with various other fishes. The aim of this study is to determine which fishes are associated with the lionfish in their shelters, and what characteristics of both the invasive and native species may influence and explain such coexistence between a predator and its potential prey. Through diving and snorkelling, we visited 141 lionfish refuges, mostly caves, where we observed 204 lionfish and 494 other fish from 16 native species. We recorded species and abundance, as well as lionfish size and abundance. Half of the lionfish were observed in groups and the majority were large-sized. The association with most fish species seems fortuitous, but three species, Gramma loreto, Chromis cyanea and Canthigaster rostrata, were frequently observed in association with lionfish. Numerous fish juveniles, most likely Scarus coeruleus, were also observed together with the invasive predator. The more commonly associated fishes, particularly G. loreto, are mostly associated with large-sized lionfish that were found in groups. The associated fishes are also generally found in groups. Gramma loreto is a potential cleaner of the lionfish; the reasons for the association between these fish species and the invasive lionfish may be more complex than a simple predator-prey relationship and are discussed based on their biological traits and previously reported lionfish trophic ecology and predation behaviour.

Sponge symbioses between Xestospongia deweerdtae and Plakortis spp. are not motivated by shared chemical defense against predators.

The recently described epizoic sponge-sponge symbioses between Xestospongia deweerdtae and two species of Plakortis present an unusual series of sponge interactions. Sponges from the genus Plakortis are fierce allelopathic competitors, rich in cytotoxic secondary metabolites, and yet X. deweerdtae flourishes as an epizoic encrustation on Plakortis deweerdtaephila and Plakortis symbiotica. Our objective in this study was to evaluate the hypothesis that X. deweerdtae grows epizoic to these two species of Plakortis due to a shared chemical defense against predators. We collected free-living individuals of X. deweerdtae and symbiotic pairs from a wide geographical range to generate crude organic extracts and a series of polarity fractions from sponge extract. We tested the deterrency of these extracts against three common coral reef predators: the bluehead wrasse, Thalassoma bifasciatum, the Caribbean sharpnose puffer, Canthigaster rostrata, and the white spotwrist hermit crab, Pagurus criniticornis. While the chemical defenses of P. deweerdtaephila and P. symbiotica are more potent than those of X. deweerdtae, all of the sponge species we tested significantly deterred feeding in all three generalist predators. The free-living form of X. deweerdtae is mostly defended across the region, with a few exceptions. The associated form of X. deweerdtae is always defended, and both species of Plakortis are very strongly defended, with puffers refusing to consume extract-treated pellets until the extract was diluted to 1/256× concentration. Using diode-array high performance liquid chromatography (HPLC) coupled with high-resolution mass spectrometry (LC-MS/IT-TOF), we found two secondary metabolites from P. deweerdtaephila, probably the cyclic endoperoxides plakinic acid I and plakinic acid K, in low concentrations in the associated—but not the free-living—form of X. deweerdtae, suggesting a possible translocation of defensive chemicals from the basibiont to the epibiont. Comparing the immense deterrency of Plakortis spp. extracts to the extracts of X. deweerdtae gives the impression that there may be some sharing of chemical defenses: one partner in the symbiosis is clearly more defended than the other and a small amount of its defensive chemistry may translocate to the partner. However, X. deweerdtae effectively deters predators with its own defensive chemistry. Multiple lines of evidence provide no support for the shared chemical defense hypothesis. Given the diversity of other potential food resources available to predators on coral reefs, it is improbable that the evolution of these specialized sponge-sponge symbioses has been driven by predation pressure.

DIVERSIDAD Y DISTRIBUCIÓN DE PECES EN EL GRADIENTE DE PROFUNDIDAD DE UNA PARED ARRECIFAL CORALINA EN LA ISLA DE SAN ANDRÉS, CARIBE COLOMBIANO

“Blue Wall”, in San Andrés Island (Colombia), is an outer reef slope with an inclination that increases with depth to nearly 90°. Such a steep gradient facilitates the identification of patterns of variation in species abundance and diversity along depth. To document such patterns in fishes associated with this habitat, 30 visual censuses were conducted along 30 x 2 m transects, located at 5 m intervals between 5-30 m depth, in which the abundance and diversity of species was estimated. A total of 2916 individuals belonging to 46 species from 21 families were recorded within transects. Ten additional species were observed outside of transects for a total richness of 56 species. The dominant species were Canthigaster rostrata, Chromis cyanea, Stegastes partitus, Thalassoma bifasciatum and Clepticus parrae, which together with four other species accounted for 92% of the total abundance. Several of these dominant species are planktivorous and abundant throughout the Caribbean and had broad ranges of vertical distribution with abundance peaks in different parts of the depth gradient. In general, there was a positive correlation between average abundance and breadth of depth distribution. Non-metric Multi-Dimensional Scaling analysis revealed distinct assemblages at each depth, which also differed significantly, but weakly, in their diversity and dominance, but not in their species richness and evenness. Shallow assemblages were clearly distinctive from deep ones, with greater differentiation between shallower than between deeper assemblages. We conclude that the fish assemblage at “Blue Wall” exhibits a structural order that can be explained, in part, by depth and that reef walls offer an excellent opportunity to examine processes responsible for patterns of community structure in coral reef fishes.

Reef fish community in presence of the lionfish (Pterois volitans) in Santa Marta, Colombian Caribbean

ABSTRACT Objective. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe) 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m2), but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus) were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9%) and Cinto (27.4%), larger sponge percentages in Morro (32.7%); Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively); corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.

First report of spawning and social organization in Hawai’ian Ambon Toby, Canthigaster amboinensis

Sharpnose puffers (Tetraodontidae: Canthigasterinae) are small demersal fishes found on tropical and subtropical reefs. They are slow moving, often cryptically colored, and typically occur in low population densities (cf. Vail and Sinclair-Taylor 2011 for report of unusual mass schooling). Thus, they have been poorly studied compared with most groups of reef fishes. Indeed, of the 35 described species, spawning in the field has been reported for only 2, with the most recent report being over 2 decades ago. These include Canthigaster valentini in the Indo-Pacific (Gladstone 1987; Gladstone and Westoby 1988), and Canthigaster rostrata of the Caribbean and tropical Atlantic (Sikkel 1990). Spawning has also been reported in captivity but not in the field for Canthigaster rivulata (see Arai and Fujita 1988), and social organization but not spawning has been reported in the field for Canthigaster punctatissima (see Kobayashi 1988).

Hurleytrematoides justinei n. sp. (Digenea: Monorchiidae) from Valentinni’s sharpnose puffer, Canthigaster valentini (Bleeker) (Tetraodontiformes: Tetraodontidae) from Heron Island, Queensland, Australia

A new species, Hurleytrematoides justinei n. sp., is described from Valentinni’s sharpnose puffer, Canthigaster valentini, from Heron Island, Queensland, Australia. It is characterized within the genus by a sinistral genital pore opening anterior to the posterior margin of the ventral sucker, a spiny ejaculatory duct ranging from 34 to 61 µm in length, and vitelline follicles extending from about the anterior margin of the testis to the posterior margin of the ventral sucker. Monorchiids are rare in the tetraodontids. This is the third species reported from the family and the first from the genus Canthigaster.

Structure of and relationships within and between the littoral, rock-substrate fish communities off four islands in the Canarian Archipelago

A total of 577 visual surveys (each of 5 min in duration and 100 m2 in area) were conducted throughout 1990 and 1991 at 32 locations off four Canary islands (i.e., Alegranza, Fuerteventura, Gran Canaria and Tenerife) with the objects of describing the coastal fish community, comparing the differences in the fish fauna within and between these islands, and determining the biotic and abiotic factors related to the structure of the fish communities. A total of 76 species were recorded; the most common were Abudefduf luridus, Canthigaster rostrata, Chromis limbatus, Sparisoma cretense and Thalassoma pavo (94.28, 86.48, 52.34, 73.31, and 94.10% frequency of occurrence, respectively). The abundance and average size of the commercially important species was greater in those locations where there was less fishing pressure. The stepwise linear regression models were capable of explaining only a low amount of variation in the dependent variables (i.e., number of species, number of individuals, average size and species diversity) of the fish community. The independent variables recorded were date, time of day, depth, slope of the substrate, substrate type, percentage of sand, percentage of algae, algal height, number of sea urchins (Diadema antillarum) and the individual islands. An ANOVA, using the islands only as independent variables, indicated that each island contributed significantly to the variation in the four dependent variables and there were significant differences among the islands. Detrended correspondence analysis (DCA) and a two-way indicator species analysis (TWINSPAN) determined associations between species and environmental attributes of the survey locations. The patterns in the TWINSPAN analysis indicated that localities had faunal resemblances based on the island off which where they were located.

Diseases Caused byTrichodina spheroidesiandCryptocaryon irritans(Ciliophora) in Wild Coral Reef Fishes

Very heavy infections of Trichodina spheroidesi apparently killed wild specimens of orange filefish Aluterus schoepfi and whitespotted filefish Cantherhines macrocerus in Puerto Rico. Possibly it is a primary pathogen under some conditions. The hyperparasite Endosphaera engelmanni occurred in this protozoan, and thus the range of both parasites was extended from the temperate zone to the tropics. Sand drums Umbrina coroides, collected off Humacao, Puerto Rico, had heavy infections of Cryptocaryon irritans, which has seldom been shown to injure wild fishes. We have not seen other examples of these diseases in more than 3,000 specimens of 270 species of wild marine fishes examined in Puerto Rico, although Cryptocaryon irritans is common in local marine aquarium fishes. Sharpnose puffers Canthigaster rostrata often cause outbreaks of Cryptocaryon irritans when placed in marine aquaria.

Spawning behavior and early life history of the sharpnose puffer,Canthigaster rivulata, in the aquarium

Spawning behavior and early life history of the sharpnose puffer,Canthigaster rivulata, in the aquarium

The courtship and spawning behaviors ofCanthigaster valentini (Tetraodontidae)

The sharpnose puffer,Canthigaster valentini, occurs in male-dominated harems of territorial females at Lizard Island (Australia). Spawning occurs daily and year-round. Males only spawn with the females of their social group, inside the female's territory. Females signal their readiness to begin courtship with a display that exposes their egg swollen abdomen. Courtship is long and males do not develop specific courtship colors or perform unique displays. Eggs are fertilized in a demersal nest and there is no parental care.

Social organization of the spotted sharpnose puffer, Canthigaster punctatissima (Tetraodontidae)

Tagged individuals of the Eastern Pacific sharpnose puffer, Canthigaster punctatissima, were studied at Punta Santa Inez, Baja California Sur. Territories were maintained by both sexes in this sexually dimorphic fish. Male puffers appear to have harems; one large male interacts with one to four smaller females. Puffers from different harems were not seen to interact except for occasional aggressive contact. Removal of a male puffer resulted in the overnight takeover of his harem by a neighboring male. Harem-forming behavior is discussed, as well as the possible role of predation.