The parasitic bopyrid isopod Pseudione tuberculata Richardson, 1904 infests the branchial chamber of species of the family Lithodidae found along the southern tip of South America. It was previously known only as a parasite of Neolithodes... more
The parasitic bopyrid isopod Pseudione tuberculata Richardson, 1904 infests the branchial chamber of species of the family Lithodidae found along the southern tip of South America. It was previously known only as a parasite of Neolithodes off the Chonos Archipelago, Chile, as well as Paralomis granulosa (Jacquinot, 1847) and Lithodes santolla (Molina, 1782) from shallow waters of the Beagle Channel, Argentina. This is the first time the parasite is documented in Chile at the Magellan Strait, located about 640 km north of the Beagle Channel, infesting mainly on juveniles of L. santolla (23.0 to 51.6 mm CL in females and from 24.0 to 48.7 mm in males). Prevalence of the parasite in crabs was 27.9% in females and 21.4% in males. Prevalence was higher than those reported in other Chilean crustaceans parasitized by other Pseudione species. Each king crab carried a single pair of P. tuberculata within the branchial chamber on the left side of the carapace. High rates of parasitism of P. tuberculata on juvenile king crabs in this area could occur in shallow water inhabited by Macrocystis pyrifera kelp due to the plant’s effect on the local hydrodynamic conditions, reducing flow and damping waves, providing habitats for several organisms. It is concluded that P. tuberculata infesting L. santolla at the Magellan strait responds in a similar way when compared with prevalence values from previous studies developed at the Beagle Channel, Argentina, where it has been reported infesting P. granulosa and L. santolla.
Density banding provides a record of performance of coral colonies over time and across environments, and offers 3 measurable variables: skeletal density, extension rate, and calcification rate. Skeleton formation is energetically... more
Density banding provides a record of performance of coral colonies over time and across environments, and offers 3 measurable variables: skeletal density, extension rate, and calcification rate. Skeleton formation is energetically expensive for corals and may be associated with other energy-dependent processes, such as reproduction. Egg production requires more energy expenditure than sperm production. Thus, calcification rate is hypothesized to be different for each gender. To evaluate differences in skeletal growth between males and females, we studied a gonochoric massive coral, Porites panamensis, from 3 regions of the Gulf of California. Colony sex was identified using histology methods, and growth parameters were measured using photo-densitometry of X-radiographs. Extension and calcification rates were significantly higher in male colonies than in females (by 18 to 23%) at 2 of our 3 study sites, while skeletal density was similar in both genders. Our results support the hypothesis of a gender bias in growth characteristics and suggest that environmental conditions may impact coral calcification differently in male and female colonies.
High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a high-latitude reef at Bahía de Los Ángeles in the northern Gulf of California. Porites panamensis corals were infested by 15 to 40 sea snails... more
High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a high-latitude reef at Bahía de Los Ángeles in the northern Gulf of California. Porites panamensis corals were infested by 15 to 40 sea snails per colony (22 ± 7.25 ind/0.1 m of Porites surface). Coral colonies were 20-30 cm tall and the average size of the sea snails were 1.7 cm (SD ± 0.238, N =152). These data indicate a change in the daily pattern of movement and feeding of the gastropod in this reef. Despite high density of J. pustulata on the reef, no soft corals were observed as damaged by the sea snail.
Abstract High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a high-latitude reef at Bahía de Los Ángeles in the northern Gulf of California. Porites panamensis corals were infested by 15 to 40 sea... more
Abstract High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a high-latitude reef at Bahía de Los Ángeles in the northern Gulf of California. Porites panamensis corals were infested by 15 to 40 sea snails per colony (22±7.25 ind 0.1 m–2 of Porites surface). Coral colonies were 20–30 cm tall and the average size of the sea snails were 1.7 cm (SD±0.238, N= 152). These data indicate a change in the daily pattern of movement and feeding of the gastropod in this reef. Despite high density of J. pustulata on ...
Sea urchins play a crucial role in the health and dynamics of reef ecosystems. Diadema mexicanum is a dominant grazer and erosive agent of the substratum in reef environments in the eastern tropical Pacific. Its reported distribution... more
Sea urchins play a crucial role in the health and dynamics of reef ecosystems. Diadema mexicanum is a dominant grazer and erosive agent of the substratum in reef environments in the eastern tropical Pacific. Its reported distribution extends from the middle of the Gulf of California (26° N) to northern Peru (6°23′ S), including oceanic islands. Here, we report the occurrence of Diadema mexicanum in Isla San Jorge (31°0′38.53″ N, 113°14′34.84″ W), the northernmost island in the Gulf of California, which extends its range an additional 600 km northward. Sea urchins, ranging in test size from 4.5 to 12.4 cm, were present at 2–6 m in October 2015. This test size was one of the largest reported for this species in the eastern tropical Pacific. Spine length in sea urchins in the upper gulf ranged from 3.3 to 15.6 cm. Variation in body size of sea urchin may reflect variation in more structurally complex reefs from isolated islands that provide shelter from predation. The reef structure of Isla San Jorge is formed by high coral cover of the scleractinian coral Porites panamensis, with an average colony height of 26.27 cm (standard error, SE ±1.58, n = 60), similar to coral reef communities of the southern Gulf of California. Although D. mexicanum is considered a great force of erosion to the substratum in reef environments in the eastern tropical Pacific, no evidence of erosion was observed at Isla San Jorge, indicating a balanced dynamic between herbivores, macroalgae, and corals.
New material collected from the Kermadec Islands verifies the presence of at least 11 scleractinian coral species and a crown-of-thorns seastar survey suggests a high density of corallivores are present at North Meyer Island (i.e.... more
New material collected from the Kermadec Islands verifies the presence of at least 11 scleractinian coral species and a crown-of-thorns seastar survey suggests a high density of corallivores are present at North Meyer Island (i.e. > 0.008 individuals per m2). Despite not currently being classified as a coral reef, tropical reef-building coral species are present in the coral community and there has been a population of Acanthaster planci present for at least three decades. This marginal coral community represents a valuable opportunity to examine climate-driven coral and coral predator transitions into high latitude locations.
